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[PATCH 1/3] btrfs: Import kernel zstd


From: Nick Terrell
Subject: [PATCH 1/3] btrfs: Import kernel zstd
Date: Mon, 27 Aug 2018 18:36:52 -0700

Import xxhash and zstd from the upstream kernel as-is. This will not
compile. The next patch in the series contains all the changes needed to
make zstd compile in grub. Only the files needed for decompression are
imported from zstd.

The files are copied from these locations:
include/linux/{xxhash,zstd}.h
lib/xxhash.c
lib/zstd/

Signed-off-by: Nick Terrell <address@hidden>
---
 grub-core/lib/zstd/bitstream.h      |  374 ++++++
 grub-core/lib/zstd/decompress.c     | 2528 +++++++++++++++++++++++++++++++++++
 grub-core/lib/zstd/entropy_common.c |  243 ++++
 grub-core/lib/zstd/error_private.h  |   53 +
 grub-core/lib/zstd/fse.h            |  575 ++++++++
 grub-core/lib/zstd/fse_decompress.c |  332 +++++
 grub-core/lib/zstd/huf.h            |  212 +++
 grub-core/lib/zstd/huf_decompress.c |  960 +++++++++++++
 grub-core/lib/zstd/mem.h            |  151 +++
 grub-core/lib/zstd/xxhash.c         |  500 +++++++
 grub-core/lib/zstd/xxhash.h         |  236 ++++
 grub-core/lib/zstd/zstd.h           | 1157 ++++++++++++++++
 grub-core/lib/zstd/zstd_common.c    |   75 ++
 grub-core/lib/zstd/zstd_internal.h  |  263 ++++
 14 files changed, 7659 insertions(+)
 create mode 100644 grub-core/lib/zstd/bitstream.h
 create mode 100644 grub-core/lib/zstd/decompress.c
 create mode 100644 grub-core/lib/zstd/entropy_common.c
 create mode 100644 grub-core/lib/zstd/error_private.h
 create mode 100644 grub-core/lib/zstd/fse.h
 create mode 100644 grub-core/lib/zstd/fse_decompress.c
 create mode 100644 grub-core/lib/zstd/huf.h
 create mode 100644 grub-core/lib/zstd/huf_decompress.c
 create mode 100644 grub-core/lib/zstd/mem.h
 create mode 100644 grub-core/lib/zstd/xxhash.c
 create mode 100644 grub-core/lib/zstd/xxhash.h
 create mode 100644 grub-core/lib/zstd/zstd.h
 create mode 100644 grub-core/lib/zstd/zstd_common.c
 create mode 100644 grub-core/lib/zstd/zstd_internal.h

diff --git a/grub-core/lib/zstd/bitstream.h b/grub-core/lib/zstd/bitstream.h
new file mode 100644
index 000000000..a826b99e1
--- /dev/null
+++ b/grub-core/lib/zstd/bitstream.h
@@ -0,0 +1,374 @@
+/*
+ * bitstream
+ * Part of FSE library
+ * header file (to include)
+ * Copyright (C) 2013-2016, Yann Collet.
+ *
+ * BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *   * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * This program is free software; you can redistribute it and/or modify it 
under
+ * the terms of the GNU General Public License version 2 as published by the
+ * Free Software Foundation. This program is dual-licensed; you may select
+ * either version 2 of the GNU General Public License ("GPL") or BSD license
+ * ("BSD").
+ *
+ * You can contact the author at :
+ * - Source repository : https://github.com/Cyan4973/FiniteStateEntropy
+ */
+#ifndef BITSTREAM_H_MODULE
+#define BITSTREAM_H_MODULE
+
+/*
+*  This API consists of small unitary functions, which must be inlined for 
best performance.
+*  Since link-time-optimization is not available for all compilers,
+*  these functions are defined into a .h to be included.
+*/
+
+/*-****************************************
+*  Dependencies
+******************************************/
+#include "error_private.h" /* error codes and messages */
+#include "mem.h"          /* unaligned access routines */
+
+/*=========================================
+*  Target specific
+=========================================*/
+#define STREAM_ACCUMULATOR_MIN_32 25
+#define STREAM_ACCUMULATOR_MIN_64 57
+#define STREAM_ACCUMULATOR_MIN ((U32)(ZSTD_32bits() ? 
STREAM_ACCUMULATOR_MIN_32 : STREAM_ACCUMULATOR_MIN_64))
+
+/*-******************************************
+*  bitStream encoding API (write forward)
+********************************************/
+/* bitStream can mix input from multiple sources.
+*  A critical property of these streams is that they encode and decode in 
**reverse** direction.
+*  So the first bit sequence you add will be the last to be read, like a LIFO 
stack.
+*/
+typedef struct {
+       size_t bitContainer;
+       int bitPos;
+       char *startPtr;
+       char *ptr;
+       char *endPtr;
+} BIT_CStream_t;
+
+ZSTD_STATIC size_t BIT_initCStream(BIT_CStream_t *bitC, void *dstBuffer, 
size_t dstCapacity);
+ZSTD_STATIC void BIT_addBits(BIT_CStream_t *bitC, size_t value, unsigned 
nbBits);
+ZSTD_STATIC void BIT_flushBits(BIT_CStream_t *bitC);
+ZSTD_STATIC size_t BIT_closeCStream(BIT_CStream_t *bitC);
+
+/* Start with initCStream, providing the size of buffer to write into.
+*  bitStream will never write outside of this buffer.
+*  `dstCapacity` must be >= sizeof(bitD->bitContainer), otherwise @return will 
be an error code.
+*
+*  bits are first added to a local register.
+*  Local register is size_t, hence 64-bits on 64-bits systems, or 32-bits on 
32-bits systems.
+*  Writing data into memory is an explicit operation, performed by the 
flushBits function.
+*  Hence keep track how many bits are potentially stored into local register 
to avoid register overflow.
+*  After a flushBits, a maximum of 7 bits might still be stored into local 
register.
+*
+*  Avoid storing elements of more than 24 bits if you want compatibility with 
32-bits bitstream readers.
+*
+*  Last operation is to close the bitStream.
+*  The function returns the final size of CStream in bytes.
+*  If data couldn't fit into `dstBuffer`, it will return a 0 ( == not storable)
+*/
+
+/*-********************************************
+*  bitStream decoding API (read backward)
+**********************************************/
+typedef struct {
+       size_t bitContainer;
+       unsigned bitsConsumed;
+       const char *ptr;
+       const char *start;
+} BIT_DStream_t;
+
+typedef enum {
+       BIT_DStream_unfinished = 0,
+       BIT_DStream_endOfBuffer = 1,
+       BIT_DStream_completed = 2,
+       BIT_DStream_overflow = 3
+} BIT_DStream_status; /* result of BIT_reloadDStream() */
+/* 1,2,4,8 would be better for bitmap combinations, but slows down performance 
a bit ... :( */
+
+ZSTD_STATIC size_t BIT_initDStream(BIT_DStream_t *bitD, const void *srcBuffer, 
size_t srcSize);
+ZSTD_STATIC size_t BIT_readBits(BIT_DStream_t *bitD, unsigned nbBits);
+ZSTD_STATIC BIT_DStream_status BIT_reloadDStream(BIT_DStream_t *bitD);
+ZSTD_STATIC unsigned BIT_endOfDStream(const BIT_DStream_t *bitD);
+
+/* Start by invoking BIT_initDStream().
+*  A chunk of the bitStream is then stored into a local register.
+*  Local register size is 64-bits on 64-bits systems, 32-bits on 32-bits 
systems (size_t).
+*  You can then retrieve bitFields stored into the local register, **in 
reverse order**.
+*  Local register is explicitly reloaded from memory by the 
BIT_reloadDStream() method.
+*  A reload guarantee a minimum of ((8*sizeof(bitD->bitContainer))-7) bits 
when its result is BIT_DStream_unfinished.
+*  Otherwise, it can be less than that, so proceed accordingly.
+*  Checking if DStream has reached its end can be performed with 
BIT_endOfDStream().
+*/
+
+/*-****************************************
+*  unsafe API
+******************************************/
+ZSTD_STATIC void BIT_addBitsFast(BIT_CStream_t *bitC, size_t value, unsigned 
nbBits);
+/* faster, but works only if value is "clean", meaning all high bits above 
nbBits are 0 */
+
+ZSTD_STATIC void BIT_flushBitsFast(BIT_CStream_t *bitC);
+/* unsafe version; does not check buffer overflow */
+
+ZSTD_STATIC size_t BIT_readBitsFast(BIT_DStream_t *bitD, unsigned nbBits);
+/* faster, but works only if nbBits >= 1 */
+
+/*-**************************************************************
+*  Internal functions
+****************************************************************/
+ZSTD_STATIC unsigned BIT_highbit32(register U32 val) { return 31 - 
__builtin_clz(val); }
+
+/*=====    Local Constants   =====*/
+static const unsigned BIT_mask[] = {0,       1,       3,       7,      0xF,    
  0x1F,     0x3F,     0x7F,      0xFF,
+                                   0x1FF,   0x3FF,   0x7FF,   0xFFF,    
0x1FFF,   0x3FFF,   0x7FFF,   0xFFFF,    0x1FFFF,
+                                   0x3FFFF, 0x7FFFF, 0xFFFFF, 0x1FFFFF, 
0x3FFFFF, 0x7FFFFF, 0xFFFFFF, 0x1FFFFFF, 0x3FFFFFF}; /* up to 26 bits */
+
+/*-**************************************************************
+*  bitStream encoding
+****************************************************************/
+/*! BIT_initCStream() :
+ *  `dstCapacity` must be > sizeof(void*)
+ *  @return : 0 if success,
+                         otherwise an error code (can be tested using 
ERR_isError() ) */
+ZSTD_STATIC size_t BIT_initCStream(BIT_CStream_t *bitC, void *startPtr, size_t 
dstCapacity)
+{
+       bitC->bitContainer = 0;
+       bitC->bitPos = 0;
+       bitC->startPtr = (char *)startPtr;
+       bitC->ptr = bitC->startPtr;
+       bitC->endPtr = bitC->startPtr + dstCapacity - sizeof(bitC->ptr);
+       if (dstCapacity <= sizeof(bitC->ptr))
+               return ERROR(dstSize_tooSmall);
+       return 0;
+}
+
+/*! BIT_addBits() :
+       can add up to 26 bits into `bitC`.
+       Does not check for register overflow ! */
+ZSTD_STATIC void BIT_addBits(BIT_CStream_t *bitC, size_t value, unsigned 
nbBits)
+{
+       bitC->bitContainer |= (value & BIT_mask[nbBits]) << bitC->bitPos;
+       bitC->bitPos += nbBits;
+}
+
+/*! BIT_addBitsFast() :
+ *  works only if `value` is _clean_, meaning all high bits above nbBits are 0 
*/
+ZSTD_STATIC void BIT_addBitsFast(BIT_CStream_t *bitC, size_t value, unsigned 
nbBits)
+{
+       bitC->bitContainer |= value << bitC->bitPos;
+       bitC->bitPos += nbBits;
+}
+
+/*! BIT_flushBitsFast() :
+ *  unsafe version; does not check buffer overflow */
+ZSTD_STATIC void BIT_flushBitsFast(BIT_CStream_t *bitC)
+{
+       size_t const nbBytes = bitC->bitPos >> 3;
+       ZSTD_writeLEST(bitC->ptr, bitC->bitContainer);
+       bitC->ptr += nbBytes;
+       bitC->bitPos &= 7;
+       bitC->bitContainer >>= nbBytes * 8; /* if bitPos >= 
sizeof(bitContainer)*8 --> undefined behavior */
+}
+
+/*! BIT_flushBits() :
+ *  safe version; check for buffer overflow, and prevents it.
+ *  note : does not signal buffer overflow. This will be revealed later on 
using BIT_closeCStream() */
+ZSTD_STATIC void BIT_flushBits(BIT_CStream_t *bitC)
+{
+       size_t const nbBytes = bitC->bitPos >> 3;
+       ZSTD_writeLEST(bitC->ptr, bitC->bitContainer);
+       bitC->ptr += nbBytes;
+       if (bitC->ptr > bitC->endPtr)
+               bitC->ptr = bitC->endPtr;
+       bitC->bitPos &= 7;
+       bitC->bitContainer >>= nbBytes * 8; /* if bitPos >= 
sizeof(bitContainer)*8 --> undefined behavior */
+}
+
+/*! BIT_closeCStream() :
+ *  @return : size of CStream, in bytes,
+                         or 0 if it could not fit into dstBuffer */
+ZSTD_STATIC size_t BIT_closeCStream(BIT_CStream_t *bitC)
+{
+       BIT_addBitsFast(bitC, 1, 1); /* endMark */
+       BIT_flushBits(bitC);
+
+       if (bitC->ptr >= bitC->endPtr)
+               return 0; /* doesn't fit within authorized budget : cancel */
+
+       return (bitC->ptr - bitC->startPtr) + (bitC->bitPos > 0);
+}
+
+/*-********************************************************
+* bitStream decoding
+**********************************************************/
+/*! BIT_initDStream() :
+*   Initialize a BIT_DStream_t.
+*   `bitD` : a pointer to an already allocated BIT_DStream_t structure.
+*   `srcSize` must be the *exact* size of the bitStream, in bytes.
+*   @return : size of stream (== srcSize) or an errorCode if a problem is 
detected
+*/
+ZSTD_STATIC size_t BIT_initDStream(BIT_DStream_t *bitD, const void *srcBuffer, 
size_t srcSize)
+{
+       if (srcSize < 1) {
+               memset(bitD, 0, sizeof(*bitD));
+               return ERROR(srcSize_wrong);
+       }
+
+       if (srcSize >= sizeof(bitD->bitContainer)) { /* normal case */
+               bitD->start = (const char *)srcBuffer;
+               bitD->ptr = (const char *)srcBuffer + srcSize - 
sizeof(bitD->bitContainer);
+               bitD->bitContainer = ZSTD_readLEST(bitD->ptr);
+               {
+                       BYTE const lastByte = ((const BYTE *)srcBuffer)[srcSize 
- 1];
+                       bitD->bitsConsumed = lastByte ? 8 - 
BIT_highbit32(lastByte) : 0; /* ensures bitsConsumed is always set */
+                       if (lastByte == 0)
+                               return ERROR(GENERIC); /* endMark not present */
+               }
+       } else {
+               bitD->start = (const char *)srcBuffer;
+               bitD->ptr = bitD->start;
+               bitD->bitContainer = *(const BYTE *)(bitD->start);
+               switch (srcSize) {
+               case 7: bitD->bitContainer += (size_t)(((const BYTE 
*)(srcBuffer))[6]) << (sizeof(bitD->bitContainer) * 8 - 16);
+               case 6: bitD->bitContainer += (size_t)(((const BYTE 
*)(srcBuffer))[5]) << (sizeof(bitD->bitContainer) * 8 - 24);
+               case 5: bitD->bitContainer += (size_t)(((const BYTE 
*)(srcBuffer))[4]) << (sizeof(bitD->bitContainer) * 8 - 32);
+               case 4: bitD->bitContainer += (size_t)(((const BYTE 
*)(srcBuffer))[3]) << 24;
+               case 3: bitD->bitContainer += (size_t)(((const BYTE 
*)(srcBuffer))[2]) << 16;
+               case 2: bitD->bitContainer += (size_t)(((const BYTE 
*)(srcBuffer))[1]) << 8;
+               default:;
+               }
+               {
+                       BYTE const lastByte = ((const BYTE *)srcBuffer)[srcSize 
- 1];
+                       bitD->bitsConsumed = lastByte ? 8 - 
BIT_highbit32(lastByte) : 0;
+                       if (lastByte == 0)
+                               return ERROR(GENERIC); /* endMark not present */
+               }
+               bitD->bitsConsumed += (U32)(sizeof(bitD->bitContainer) - 
srcSize) * 8;
+       }
+
+       return srcSize;
+}
+
+ZSTD_STATIC size_t BIT_getUpperBits(size_t bitContainer, U32 const start) { 
return bitContainer >> start; }
+
+ZSTD_STATIC size_t BIT_getMiddleBits(size_t bitContainer, U32 const start, U32 
const nbBits) { return (bitContainer >> start) & BIT_mask[nbBits]; }
+
+ZSTD_STATIC size_t BIT_getLowerBits(size_t bitContainer, U32 const nbBits) { 
return bitContainer & BIT_mask[nbBits]; }
+
+/*! BIT_lookBits() :
+ *  Provides next n bits from local register.
+ *  local register is not modified.
+ *  On 32-bits, maxNbBits==24.
+ *  On 64-bits, maxNbBits==56.
+ *  @return : value extracted
+ */
+ZSTD_STATIC size_t BIT_lookBits(const BIT_DStream_t *bitD, U32 nbBits)
+{
+       U32 const bitMask = sizeof(bitD->bitContainer) * 8 - 1;
+       return ((bitD->bitContainer << (bitD->bitsConsumed & bitMask)) >> 1) >> 
((bitMask - nbBits) & bitMask);
+}
+
+/*! BIT_lookBitsFast() :
+*   unsafe version; only works only if nbBits >= 1 */
+ZSTD_STATIC size_t BIT_lookBitsFast(const BIT_DStream_t *bitD, U32 nbBits)
+{
+       U32 const bitMask = sizeof(bitD->bitContainer) * 8 - 1;
+       return (bitD->bitContainer << (bitD->bitsConsumed & bitMask)) >> 
(((bitMask + 1) - nbBits) & bitMask);
+}
+
+ZSTD_STATIC void BIT_skipBits(BIT_DStream_t *bitD, U32 nbBits) { 
bitD->bitsConsumed += nbBits; }
+
+/*! BIT_readBits() :
+ *  Read (consume) next n bits from local register and update.
+ *  Pay attention to not read more than nbBits contained into local register.
+ *  @return : extracted value.
+ */
+ZSTD_STATIC size_t BIT_readBits(BIT_DStream_t *bitD, U32 nbBits)
+{
+       size_t const value = BIT_lookBits(bitD, nbBits);
+       BIT_skipBits(bitD, nbBits);
+       return value;
+}
+
+/*! BIT_readBitsFast() :
+*   unsafe version; only works only if nbBits >= 1 */
+ZSTD_STATIC size_t BIT_readBitsFast(BIT_DStream_t *bitD, U32 nbBits)
+{
+       size_t const value = BIT_lookBitsFast(bitD, nbBits);
+       BIT_skipBits(bitD, nbBits);
+       return value;
+}
+
+/*! BIT_reloadDStream() :
+*   Refill `bitD` from buffer previously set in BIT_initDStream() .
+*   This function is safe, it guarantees it will not read beyond src buffer.
+*   @return : status of `BIT_DStream_t` internal register.
+                         if status == BIT_DStream_unfinished, internal 
register is filled with >= (sizeof(bitD->bitContainer)*8 - 7) bits */
+ZSTD_STATIC BIT_DStream_status BIT_reloadDStream(BIT_DStream_t *bitD)
+{
+       if (bitD->bitsConsumed > (sizeof(bitD->bitContainer) * 8)) /* should 
not happen => corruption detected */
+               return BIT_DStream_overflow;
+
+       if (bitD->ptr >= bitD->start + sizeof(bitD->bitContainer)) {
+               bitD->ptr -= bitD->bitsConsumed >> 3;
+               bitD->bitsConsumed &= 7;
+               bitD->bitContainer = ZSTD_readLEST(bitD->ptr);
+               return BIT_DStream_unfinished;
+       }
+       if (bitD->ptr == bitD->start) {
+               if (bitD->bitsConsumed < sizeof(bitD->bitContainer) * 8)
+                       return BIT_DStream_endOfBuffer;
+               return BIT_DStream_completed;
+       }
+       {
+               U32 nbBytes = bitD->bitsConsumed >> 3;
+               BIT_DStream_status result = BIT_DStream_unfinished;
+               if (bitD->ptr - nbBytes < bitD->start) {
+                       nbBytes = (U32)(bitD->ptr - bitD->start); /* ptr > 
start */
+                       result = BIT_DStream_endOfBuffer;
+               }
+               bitD->ptr -= nbBytes;
+               bitD->bitsConsumed -= nbBytes * 8;
+               bitD->bitContainer = ZSTD_readLEST(bitD->ptr); /* reminder : 
srcSize > sizeof(bitD) */
+               return result;
+       }
+}
+
+/*! BIT_endOfDStream() :
+*   @return Tells if DStream has exactly reached its end (all bits consumed).
+*/
+ZSTD_STATIC unsigned BIT_endOfDStream(const BIT_DStream_t *DStream)
+{
+       return ((DStream->ptr == DStream->start) && (DStream->bitsConsumed == 
sizeof(DStream->bitContainer) * 8));
+}
+
+#endif /* BITSTREAM_H_MODULE */
diff --git a/grub-core/lib/zstd/decompress.c b/grub-core/lib/zstd/decompress.c
new file mode 100644
index 000000000..b17846725
--- /dev/null
+++ b/grub-core/lib/zstd/decompress.c
@@ -0,0 +1,2528 @@
+/**
+ * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of https://github.com/facebook/zstd.
+ * An additional grant of patent rights can be found in the PATENTS file in the
+ * same directory.
+ *
+ * This program is free software; you can redistribute it and/or modify it 
under
+ * the terms of the GNU General Public License version 2 as published by the
+ * Free Software Foundation. This program is dual-licensed; you may select
+ * either version 2 of the GNU General Public License ("GPL") or BSD license
+ * ("BSD").
+ */
+
+/* ***************************************************************
+*  Tuning parameters
+*****************************************************************/
+/*!
+*  MAXWINDOWSIZE_DEFAULT :
+*  maximum window size accepted by DStream, by default.
+*  Frames requiring more memory will be rejected.
+*/
+#ifndef ZSTD_MAXWINDOWSIZE_DEFAULT
+#define ZSTD_MAXWINDOWSIZE_DEFAULT ((1 << ZSTD_WINDOWLOG_MAX) + 1) /* defined 
within zstd.h */
+#endif
+
+/*-*******************************************************
+*  Dependencies
+*********************************************************/
+#include "fse.h"
+#include "huf.h"
+#include "mem.h" /* low level memory routines */
+#include "zstd_internal.h"
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/string.h> /* memcpy, memmove, memset */
+
+#define ZSTD_PREFETCH(ptr) __builtin_prefetch(ptr, 0, 0)
+
+/*-*************************************
+*  Macros
+***************************************/
+#define ZSTD_isError ERR_isError /* for inlining */
+#define FSE_isError ERR_isError
+#define HUF_isError ERR_isError
+
+/*_*******************************************************
+*  Memory operations
+**********************************************************/
+static void ZSTD_copy4(void *dst, const void *src) { memcpy(dst, src, 4); }
+
+/*-*************************************************************
+*   Context management
+***************************************************************/
+typedef enum {
+       ZSTDds_getFrameHeaderSize,
+       ZSTDds_decodeFrameHeader,
+       ZSTDds_decodeBlockHeader,
+       ZSTDds_decompressBlock,
+       ZSTDds_decompressLastBlock,
+       ZSTDds_checkChecksum,
+       ZSTDds_decodeSkippableHeader,
+       ZSTDds_skipFrame
+} ZSTD_dStage;
+
+typedef struct {
+       FSE_DTable LLTable[FSE_DTABLE_SIZE_U32(LLFSELog)];
+       FSE_DTable OFTable[FSE_DTABLE_SIZE_U32(OffFSELog)];
+       FSE_DTable MLTable[FSE_DTABLE_SIZE_U32(MLFSELog)];
+       HUF_DTable hufTable[HUF_DTABLE_SIZE(HufLog)]; /* can accommodate 
HUF_decompress4X */
+       U64 workspace[HUF_DECOMPRESS_WORKSPACE_SIZE_U32 / 2];
+       U32 rep[ZSTD_REP_NUM];
+} ZSTD_entropyTables_t;
+
+struct ZSTD_DCtx_s {
+       const FSE_DTable *LLTptr;
+       const FSE_DTable *MLTptr;
+       const FSE_DTable *OFTptr;
+       const HUF_DTable *HUFptr;
+       ZSTD_entropyTables_t entropy;
+       const void *previousDstEnd; /* detect continuity */
+       const void *base;          /* start of curr segment */
+       const void *vBase;        /* virtual start of previous segment if it 
was just before curr one */
+       const void *dictEnd;    /* end of previous segment */
+       size_t expected;
+       ZSTD_frameParams fParams;
+       blockType_e bType; /* used in ZSTD_decompressContinue(), to transfer 
blockType between header decoding and block decoding stages */
+       ZSTD_dStage stage;
+       U32 litEntropy;
+       U32 fseEntropy;
+       struct xxh64_state xxhState;
+       size_t headerSize;
+       U32 dictID;
+       const BYTE *litPtr;
+       ZSTD_customMem customMem;
+       size_t litSize;
+       size_t rleSize;
+       BYTE litBuffer[ZSTD_BLOCKSIZE_ABSOLUTEMAX + WILDCOPY_OVERLENGTH];
+       BYTE headerBuffer[ZSTD_FRAMEHEADERSIZE_MAX];
+}; /* typedef'd to ZSTD_DCtx within "zstd.h" */
+
+size_t ZSTD_DCtxWorkspaceBound(void) { return ZSTD_ALIGN(sizeof(ZSTD_stack)) + 
ZSTD_ALIGN(sizeof(ZSTD_DCtx)); }
+
+size_t ZSTD_decompressBegin(ZSTD_DCtx *dctx)
+{
+       dctx->expected = ZSTD_frameHeaderSize_prefix;
+       dctx->stage = ZSTDds_getFrameHeaderSize;
+       dctx->previousDstEnd = NULL;
+       dctx->base = NULL;
+       dctx->vBase = NULL;
+       dctx->dictEnd = NULL;
+       dctx->entropy.hufTable[0] = (HUF_DTable)((HufLog)*0x1000001); /* cover 
both little and big endian */
+       dctx->litEntropy = dctx->fseEntropy = 0;
+       dctx->dictID = 0;
+       ZSTD_STATIC_ASSERT(sizeof(dctx->entropy.rep) == sizeof(repStartValue));
+       memcpy(dctx->entropy.rep, repStartValue, sizeof(repStartValue)); /* 
initial repcodes */
+       dctx->LLTptr = dctx->entropy.LLTable;
+       dctx->MLTptr = dctx->entropy.MLTable;
+       dctx->OFTptr = dctx->entropy.OFTable;
+       dctx->HUFptr = dctx->entropy.hufTable;
+       return 0;
+}
+
+ZSTD_DCtx *ZSTD_createDCtx_advanced(ZSTD_customMem customMem)
+{
+       ZSTD_DCtx *dctx;
+
+       if (!customMem.customAlloc || !customMem.customFree)
+               return NULL;
+
+       dctx = (ZSTD_DCtx *)ZSTD_malloc(sizeof(ZSTD_DCtx), customMem);
+       if (!dctx)
+               return NULL;
+       memcpy(&dctx->customMem, &customMem, sizeof(customMem));
+       ZSTD_decompressBegin(dctx);
+       return dctx;
+}
+
+ZSTD_DCtx *ZSTD_initDCtx(void *workspace, size_t workspaceSize)
+{
+       ZSTD_customMem const stackMem = ZSTD_initStack(workspace, 
workspaceSize);
+       return ZSTD_createDCtx_advanced(stackMem);
+}
+
+size_t ZSTD_freeDCtx(ZSTD_DCtx *dctx)
+{
+       if (dctx == NULL)
+               return 0; /* support free on NULL */
+       ZSTD_free(dctx, dctx->customMem);
+       return 0; /* reserved as a potential error code in the future */
+}
+
+void ZSTD_copyDCtx(ZSTD_DCtx *dstDCtx, const ZSTD_DCtx *srcDCtx)
+{
+       size_t const workSpaceSize = (ZSTD_BLOCKSIZE_ABSOLUTEMAX + 
WILDCOPY_OVERLENGTH) + ZSTD_frameHeaderSize_max;
+       memcpy(dstDCtx, srcDCtx, sizeof(ZSTD_DCtx) - workSpaceSize); /* no need 
to copy workspace */
+}
+
+static void ZSTD_refDDict(ZSTD_DCtx *dstDCtx, const ZSTD_DDict *ddict);
+
+/*-*************************************************************
+*   Decompression section
+***************************************************************/
+
+/*! ZSTD_isFrame() :
+ *  Tells if the content of `buffer` starts with a valid Frame Identifier.
+ *  Note : Frame Identifier is 4 bytes. If `size < 4`, @return will always be 
0.
+ *  Note 2 : Legacy Frame Identifiers are considered valid only if Legacy 
Support is enabled.
+ *  Note 3 : Skippable Frame Identifiers are considered valid. */
+unsigned ZSTD_isFrame(const void *buffer, size_t size)
+{
+       if (size < 4)
+               return 0;
+       {
+               U32 const magic = ZSTD_readLE32(buffer);
+               if (magic == ZSTD_MAGICNUMBER)
+                       return 1;
+               if ((magic & 0xFFFFFFF0U) == ZSTD_MAGIC_SKIPPABLE_START)
+                       return 1;
+       }
+       return 0;
+}
+
+/** ZSTD_frameHeaderSize() :
+*   srcSize must be >= ZSTD_frameHeaderSize_prefix.
+*   @return : size of the Frame Header */
+static size_t ZSTD_frameHeaderSize(const void *src, size_t srcSize)
+{
+       if (srcSize < ZSTD_frameHeaderSize_prefix)
+               return ERROR(srcSize_wrong);
+       {
+               BYTE const fhd = ((const BYTE *)src)[4];
+               U32 const dictID = fhd & 3;
+               U32 const singleSegment = (fhd >> 5) & 1;
+               U32 const fcsId = fhd >> 6;
+               return ZSTD_frameHeaderSize_prefix + !singleSegment + 
ZSTD_did_fieldSize[dictID] + ZSTD_fcs_fieldSize[fcsId] + (singleSegment && 
!fcsId);
+       }
+}
+
+/** ZSTD_getFrameParams() :
+*   decode Frame Header, or require larger `srcSize`.
+*   @return : 0, `fparamsPtr` is correctly filled,
+*            >0, `srcSize` is too small, result is expected `srcSize`,
+*             or an error code, which can be tested using ZSTD_isError() */
+size_t ZSTD_getFrameParams(ZSTD_frameParams *fparamsPtr, const void *src, 
size_t srcSize)
+{
+       const BYTE *ip = (const BYTE *)src;
+
+       if (srcSize < ZSTD_frameHeaderSize_prefix)
+               return ZSTD_frameHeaderSize_prefix;
+       if (ZSTD_readLE32(src) != ZSTD_MAGICNUMBER) {
+               if ((ZSTD_readLE32(src) & 0xFFFFFFF0U) == 
ZSTD_MAGIC_SKIPPABLE_START) {
+                       if (srcSize < ZSTD_skippableHeaderSize)
+                               return ZSTD_skippableHeaderSize; /* magic 
number + skippable frame length */
+                       memset(fparamsPtr, 0, sizeof(*fparamsPtr));
+                       fparamsPtr->frameContentSize = ZSTD_readLE32((const 
char *)src + 4);
+                       fparamsPtr->windowSize = 0; /* windowSize==0 means a 
frame is skippable */
+                       return 0;
+               }
+               return ERROR(prefix_unknown);
+       }
+
+       /* ensure there is enough `srcSize` to fully read/decode frame header */
+       {
+               size_t const fhsize = ZSTD_frameHeaderSize(src, srcSize);
+               if (srcSize < fhsize)
+                       return fhsize;
+       }
+
+       {
+               BYTE const fhdByte = ip[4];
+               size_t pos = 5;
+               U32 const dictIDSizeCode = fhdByte & 3;
+               U32 const checksumFlag = (fhdByte >> 2) & 1;
+               U32 const singleSegment = (fhdByte >> 5) & 1;
+               U32 const fcsID = fhdByte >> 6;
+               U32 const windowSizeMax = 1U << ZSTD_WINDOWLOG_MAX;
+               U32 windowSize = 0;
+               U32 dictID = 0;
+               U64 frameContentSize = 0;
+               if ((fhdByte & 0x08) != 0)
+                       return ERROR(frameParameter_unsupported); /* reserved 
bits, which must be zero */
+               if (!singleSegment) {
+                       BYTE const wlByte = ip[pos++];
+                       U32 const windowLog = (wlByte >> 3) + 
ZSTD_WINDOWLOG_ABSOLUTEMIN;
+                       if (windowLog > ZSTD_WINDOWLOG_MAX)
+                               return ERROR(frameParameter_windowTooLarge); /* 
avoids issue with 1 << windowLog */
+                       windowSize = (1U << windowLog);
+                       windowSize += (windowSize >> 3) * (wlByte & 7);
+               }
+
+               switch (dictIDSizeCode) {
+               default: /* impossible */
+               case 0: break;
+               case 1:
+                       dictID = ip[pos];
+                       pos++;
+                       break;
+               case 2:
+                       dictID = ZSTD_readLE16(ip + pos);
+                       pos += 2;
+                       break;
+               case 3:
+                       dictID = ZSTD_readLE32(ip + pos);
+                       pos += 4;
+                       break;
+               }
+               switch (fcsID) {
+               default: /* impossible */
+               case 0:
+                       if (singleSegment)
+                               frameContentSize = ip[pos];
+                       break;
+               case 1: frameContentSize = ZSTD_readLE16(ip + pos) + 256; break;
+               case 2: frameContentSize = ZSTD_readLE32(ip + pos); break;
+               case 3: frameContentSize = ZSTD_readLE64(ip + pos); break;
+               }
+               if (!windowSize)
+                       windowSize = (U32)frameContentSize;
+               if (windowSize > windowSizeMax)
+                       return ERROR(frameParameter_windowTooLarge);
+               fparamsPtr->frameContentSize = frameContentSize;
+               fparamsPtr->windowSize = windowSize;
+               fparamsPtr->dictID = dictID;
+               fparamsPtr->checksumFlag = checksumFlag;
+       }
+       return 0;
+}
+
+/** ZSTD_getFrameContentSize() :
+*   compatible with legacy mode
+*   @return : decompressed size of the single frame pointed to be `src` if 
known, otherwise
+*             - ZSTD_CONTENTSIZE_UNKNOWN if the size cannot be determined
+*             - ZSTD_CONTENTSIZE_ERROR if an error occurred (e.g. invalid 
magic number, srcSize too small) */
+unsigned long long ZSTD_getFrameContentSize(const void *src, size_t srcSize)
+{
+       {
+               ZSTD_frameParams fParams;
+               if (ZSTD_getFrameParams(&fParams, src, srcSize) != 0)
+                       return ZSTD_CONTENTSIZE_ERROR;
+               if (fParams.windowSize == 0) {
+                       /* Either skippable or empty frame, size == 0 either 
way */
+                       return 0;
+               } else if (fParams.frameContentSize != 0) {
+                       return fParams.frameContentSize;
+               } else {
+                       return ZSTD_CONTENTSIZE_UNKNOWN;
+               }
+       }
+}
+
+/** ZSTD_findDecompressedSize() :
+ *  compatible with legacy mode
+ *  `srcSize` must be the exact length of some number of ZSTD compressed and/or
+ *      skippable frames
+ *  @return : decompressed size of the frames contained */
+unsigned long long ZSTD_findDecompressedSize(const void *src, size_t srcSize)
+{
+       {
+               unsigned long long totalDstSize = 0;
+               while (srcSize >= ZSTD_frameHeaderSize_prefix) {
+                       const U32 magicNumber = ZSTD_readLE32(src);
+
+                       if ((magicNumber & 0xFFFFFFF0U) == 
ZSTD_MAGIC_SKIPPABLE_START) {
+                               size_t skippableSize;
+                               if (srcSize < ZSTD_skippableHeaderSize)
+                                       return ERROR(srcSize_wrong);
+                               skippableSize = ZSTD_readLE32((const BYTE *)src 
+ 4) + ZSTD_skippableHeaderSize;
+                               if (srcSize < skippableSize) {
+                                       return ZSTD_CONTENTSIZE_ERROR;
+                               }
+
+                               src = (const BYTE *)src + skippableSize;
+                               srcSize -= skippableSize;
+                               continue;
+                       }
+
+                       {
+                               unsigned long long const ret = 
ZSTD_getFrameContentSize(src, srcSize);
+                               if (ret >= ZSTD_CONTENTSIZE_ERROR)
+                                       return ret;
+
+                               /* check for overflow */
+                               if (totalDstSize + ret < totalDstSize)
+                                       return ZSTD_CONTENTSIZE_ERROR;
+                               totalDstSize += ret;
+                       }
+                       {
+                               size_t const frameSrcSize = 
ZSTD_findFrameCompressedSize(src, srcSize);
+                               if (ZSTD_isError(frameSrcSize)) {
+                                       return ZSTD_CONTENTSIZE_ERROR;
+                               }
+
+                               src = (const BYTE *)src + frameSrcSize;
+                               srcSize -= frameSrcSize;
+                       }
+               }
+
+               if (srcSize) {
+                       return ZSTD_CONTENTSIZE_ERROR;
+               }
+
+               return totalDstSize;
+       }
+}
+
+/** ZSTD_decodeFrameHeader() :
+*   `headerSize` must be the size provided by ZSTD_frameHeaderSize().
+*   @return : 0 if success, or an error code, which can be tested using 
ZSTD_isError() */
+static size_t ZSTD_decodeFrameHeader(ZSTD_DCtx *dctx, const void *src, size_t 
headerSize)
+{
+       size_t const result = ZSTD_getFrameParams(&(dctx->fParams), src, 
headerSize);
+       if (ZSTD_isError(result))
+               return result; /* invalid header */
+       if (result > 0)
+               return ERROR(srcSize_wrong); /* headerSize too small */
+       if (dctx->fParams.dictID && (dctx->dictID != dctx->fParams.dictID))
+               return ERROR(dictionary_wrong);
+       if (dctx->fParams.checksumFlag)
+               xxh64_reset(&dctx->xxhState, 0);
+       return 0;
+}
+
+typedef struct {
+       blockType_e blockType;
+       U32 lastBlock;
+       U32 origSize;
+} blockProperties_t;
+
+/*! ZSTD_getcBlockSize() :
+*   Provides the size of compressed block from block header `src` */
+size_t ZSTD_getcBlockSize(const void *src, size_t srcSize, blockProperties_t 
*bpPtr)
+{
+       if (srcSize < ZSTD_blockHeaderSize)
+               return ERROR(srcSize_wrong);
+       {
+               U32 const cBlockHeader = ZSTD_readLE24(src);
+               U32 const cSize = cBlockHeader >> 3;
+               bpPtr->lastBlock = cBlockHeader & 1;
+               bpPtr->blockType = (blockType_e)((cBlockHeader >> 1) & 3);
+               bpPtr->origSize = cSize; /* only useful for RLE */
+               if (bpPtr->blockType == bt_rle)
+                       return 1;
+               if (bpPtr->blockType == bt_reserved)
+                       return ERROR(corruption_detected);
+               return cSize;
+       }
+}
+
+static size_t ZSTD_copyRawBlock(void *dst, size_t dstCapacity, const void 
*src, size_t srcSize)
+{
+       if (srcSize > dstCapacity)
+               return ERROR(dstSize_tooSmall);
+       memcpy(dst, src, srcSize);
+       return srcSize;
+}
+
+static size_t ZSTD_setRleBlock(void *dst, size_t dstCapacity, const void *src, 
size_t srcSize, size_t regenSize)
+{
+       if (srcSize != 1)
+               return ERROR(srcSize_wrong);
+       if (regenSize > dstCapacity)
+               return ERROR(dstSize_tooSmall);
+       memset(dst, *(const BYTE *)src, regenSize);
+       return regenSize;
+}
+
+/*! ZSTD_decodeLiteralsBlock() :
+       @return : nb of bytes read from src (< srcSize ) */
+size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx *dctx, const void *src, size_t 
srcSize) /* note : srcSize < BLOCKSIZE */
+{
+       if (srcSize < MIN_CBLOCK_SIZE)
+               return ERROR(corruption_detected);
+
+       {
+               const BYTE *const istart = (const BYTE *)src;
+               symbolEncodingType_e const litEncType = 
(symbolEncodingType_e)(istart[0] & 3);
+
+               switch (litEncType) {
+               case set_repeat:
+                       if (dctx->litEntropy == 0)
+                               return ERROR(dictionary_corrupted);
+               /* fall-through */
+               case set_compressed:
+                       if (srcSize < 5)
+                               return ERROR(corruption_detected); /* srcSize 
>= MIN_CBLOCK_SIZE == 3; here we need up to 5 for case 3 */
+                       {
+                               size_t lhSize, litSize, litCSize;
+                               U32 singleStream = 0;
+                               U32 const lhlCode = (istart[0] >> 2) & 3;
+                               U32 const lhc = ZSTD_readLE32(istart);
+                               switch (lhlCode) {
+                               case 0:
+                               case 1:
+                               default: /* note : default is impossible, since 
lhlCode into [0..3] */
+                                       /* 2 - 2 - 10 - 10 */
+                                       singleStream = !lhlCode;
+                                       lhSize = 3;
+                                       litSize = (lhc >> 4) & 0x3FF;
+                                       litCSize = (lhc >> 14) & 0x3FF;
+                                       break;
+                               case 2:
+                                       /* 2 - 2 - 14 - 14 */
+                                       lhSize = 4;
+                                       litSize = (lhc >> 4) & 0x3FFF;
+                                       litCSize = lhc >> 18;
+                                       break;
+                               case 3:
+                                       /* 2 - 2 - 18 - 18 */
+                                       lhSize = 5;
+                                       litSize = (lhc >> 4) & 0x3FFFF;
+                                       litCSize = (lhc >> 22) + (istart[4] << 
10);
+                                       break;
+                               }
+                               if (litSize > ZSTD_BLOCKSIZE_ABSOLUTEMAX)
+                                       return ERROR(corruption_detected);
+                               if (litCSize + lhSize > srcSize)
+                                       return ERROR(corruption_detected);
+
+                               if (HUF_isError(
+                                       (litEncType == set_repeat)
+                                           ? (singleStream ? 
HUF_decompress1X_usingDTable(dctx->litBuffer, litSize, istart + lhSize, 
litCSize, dctx->HUFptr)
+                                                           : 
HUF_decompress4X_usingDTable(dctx->litBuffer, litSize, istart + lhSize, 
litCSize, dctx->HUFptr))
+                                           : (singleStream
+                                                  ? 
HUF_decompress1X2_DCtx_wksp(dctx->entropy.hufTable, dctx->litBuffer, litSize, 
istart + lhSize, litCSize,
+                                                                               
 dctx->entropy.workspace, sizeof(dctx->entropy.workspace))
+                                                  : 
HUF_decompress4X_hufOnly_wksp(dctx->entropy.hufTable, dctx->litBuffer, litSize, 
istart + lhSize, litCSize,
+                                                                               
   dctx->entropy.workspace, sizeof(dctx->entropy.workspace)))))
+                                       return ERROR(corruption_detected);
+
+                               dctx->litPtr = dctx->litBuffer;
+                               dctx->litSize = litSize;
+                               dctx->litEntropy = 1;
+                               if (litEncType == set_compressed)
+                                       dctx->HUFptr = dctx->entropy.hufTable;
+                               memset(dctx->litBuffer + dctx->litSize, 0, 
WILDCOPY_OVERLENGTH);
+                               return litCSize + lhSize;
+                       }
+
+               case set_basic: {
+                       size_t litSize, lhSize;
+                       U32 const lhlCode = ((istart[0]) >> 2) & 3;
+                       switch (lhlCode) {
+                       case 0:
+                       case 2:
+                       default: /* note : default is impossible, since lhlCode 
into [0..3] */
+                               lhSize = 1;
+                               litSize = istart[0] >> 3;
+                               break;
+                       case 1:
+                               lhSize = 2;
+                               litSize = ZSTD_readLE16(istart) >> 4;
+                               break;
+                       case 3:
+                               lhSize = 3;
+                               litSize = ZSTD_readLE24(istart) >> 4;
+                               break;
+                       }
+
+                       if (lhSize + litSize + WILDCOPY_OVERLENGTH > srcSize) { 
/* risk reading beyond src buffer with wildcopy */
+                               if (litSize + lhSize > srcSize)
+                                       return ERROR(corruption_detected);
+                               memcpy(dctx->litBuffer, istart + lhSize, 
litSize);
+                               dctx->litPtr = dctx->litBuffer;
+                               dctx->litSize = litSize;
+                               memset(dctx->litBuffer + dctx->litSize, 0, 
WILDCOPY_OVERLENGTH);
+                               return lhSize + litSize;
+                       }
+                       /* direct reference into compressed stream */
+                       dctx->litPtr = istart + lhSize;
+                       dctx->litSize = litSize;
+                       return lhSize + litSize;
+               }
+
+               case set_rle: {
+                       U32 const lhlCode = ((istart[0]) >> 2) & 3;
+                       size_t litSize, lhSize;
+                       switch (lhlCode) {
+                       case 0:
+                       case 2:
+                       default: /* note : default is impossible, since lhlCode 
into [0..3] */
+                               lhSize = 1;
+                               litSize = istart[0] >> 3;
+                               break;
+                       case 1:
+                               lhSize = 2;
+                               litSize = ZSTD_readLE16(istart) >> 4;
+                               break;
+                       case 3:
+                               lhSize = 3;
+                               litSize = ZSTD_readLE24(istart) >> 4;
+                               if (srcSize < 4)
+                                       return ERROR(corruption_detected); /* 
srcSize >= MIN_CBLOCK_SIZE == 3; here we need lhSize+1 = 4 */
+                               break;
+                       }
+                       if (litSize > ZSTD_BLOCKSIZE_ABSOLUTEMAX)
+                               return ERROR(corruption_detected);
+                       memset(dctx->litBuffer, istart[lhSize], litSize + 
WILDCOPY_OVERLENGTH);
+                       dctx->litPtr = dctx->litBuffer;
+                       dctx->litSize = litSize;
+                       return lhSize + 1;
+               }
+               default:
+                       return ERROR(corruption_detected); /* impossible */
+               }
+       }
+}
+
+typedef union {
+       FSE_decode_t realData;
+       U32 alignedBy4;
+} FSE_decode_t4;
+
+static const FSE_decode_t4 LL_defaultDTable[(1 << LL_DEFAULTNORMLOG) + 1] = {
+    {{LL_DEFAULTNORMLOG, 1, 1}}, /* header : tableLog, fastMode, fastMode */
+    {{0, 0, 4}},                /* 0 : base, symbol, bits */
+    {{16, 0, 4}},
+    {{32, 1, 5}},
+    {{0, 3, 5}},
+    {{0, 4, 5}},
+    {{0, 6, 5}},
+    {{0, 7, 5}},
+    {{0, 9, 5}},
+    {{0, 10, 5}},
+    {{0, 12, 5}},
+    {{0, 14, 6}},
+    {{0, 16, 5}},
+    {{0, 18, 5}},
+    {{0, 19, 5}},
+    {{0, 21, 5}},
+    {{0, 22, 5}},
+    {{0, 24, 5}},
+    {{32, 25, 5}},
+    {{0, 26, 5}},
+    {{0, 27, 6}},
+    {{0, 29, 6}},
+    {{0, 31, 6}},
+    {{32, 0, 4}},
+    {{0, 1, 4}},
+    {{0, 2, 5}},
+    {{32, 4, 5}},
+    {{0, 5, 5}},
+    {{32, 7, 5}},
+    {{0, 8, 5}},
+    {{32, 10, 5}},
+    {{0, 11, 5}},
+    {{0, 13, 6}},
+    {{32, 16, 5}},
+    {{0, 17, 5}},
+    {{32, 19, 5}},
+    {{0, 20, 5}},
+    {{32, 22, 5}},
+    {{0, 23, 5}},
+    {{0, 25, 4}},
+    {{16, 25, 4}},
+    {{32, 26, 5}},
+    {{0, 28, 6}},
+    {{0, 30, 6}},
+    {{48, 0, 4}},
+    {{16, 1, 4}},
+    {{32, 2, 5}},
+    {{32, 3, 5}},
+    {{32, 5, 5}},
+    {{32, 6, 5}},
+    {{32, 8, 5}},
+    {{32, 9, 5}},
+    {{32, 11, 5}},
+    {{32, 12, 5}},
+    {{0, 15, 6}},
+    {{32, 17, 5}},
+    {{32, 18, 5}},
+    {{32, 20, 5}},
+    {{32, 21, 5}},
+    {{32, 23, 5}},
+    {{32, 24, 5}},
+    {{0, 35, 6}},
+    {{0, 34, 6}},
+    {{0, 33, 6}},
+    {{0, 32, 6}},
+}; /* LL_defaultDTable */
+
+static const FSE_decode_t4 ML_defaultDTable[(1 << ML_DEFAULTNORMLOG) + 1] = {
+    {{ML_DEFAULTNORMLOG, 1, 1}}, /* header : tableLog, fastMode, fastMode */
+    {{0, 0, 6}},                /* 0 : base, symbol, bits */
+    {{0, 1, 4}},
+    {{32, 2, 5}},
+    {{0, 3, 5}},
+    {{0, 5, 5}},
+    {{0, 6, 5}},
+    {{0, 8, 5}},
+    {{0, 10, 6}},
+    {{0, 13, 6}},
+    {{0, 16, 6}},
+    {{0, 19, 6}},
+    {{0, 22, 6}},
+    {{0, 25, 6}},
+    {{0, 28, 6}},
+    {{0, 31, 6}},
+    {{0, 33, 6}},
+    {{0, 35, 6}},
+    {{0, 37, 6}},
+    {{0, 39, 6}},
+    {{0, 41, 6}},
+    {{0, 43, 6}},
+    {{0, 45, 6}},
+    {{16, 1, 4}},
+    {{0, 2, 4}},
+    {{32, 3, 5}},
+    {{0, 4, 5}},
+    {{32, 6, 5}},
+    {{0, 7, 5}},
+    {{0, 9, 6}},
+    {{0, 12, 6}},
+    {{0, 15, 6}},
+    {{0, 18, 6}},
+    {{0, 21, 6}},
+    {{0, 24, 6}},
+    {{0, 27, 6}},
+    {{0, 30, 6}},
+    {{0, 32, 6}},
+    {{0, 34, 6}},
+    {{0, 36, 6}},
+    {{0, 38, 6}},
+    {{0, 40, 6}},
+    {{0, 42, 6}},
+    {{0, 44, 6}},
+    {{32, 1, 4}},
+    {{48, 1, 4}},
+    {{16, 2, 4}},
+    {{32, 4, 5}},
+    {{32, 5, 5}},
+    {{32, 7, 5}},
+    {{32, 8, 5}},
+    {{0, 11, 6}},
+    {{0, 14, 6}},
+    {{0, 17, 6}},
+    {{0, 20, 6}},
+    {{0, 23, 6}},
+    {{0, 26, 6}},
+    {{0, 29, 6}},
+    {{0, 52, 6}},
+    {{0, 51, 6}},
+    {{0, 50, 6}},
+    {{0, 49, 6}},
+    {{0, 48, 6}},
+    {{0, 47, 6}},
+    {{0, 46, 6}},
+}; /* ML_defaultDTable */
+
+static const FSE_decode_t4 OF_defaultDTable[(1 << OF_DEFAULTNORMLOG) + 1] = {
+    {{OF_DEFAULTNORMLOG, 1, 1}}, /* header : tableLog, fastMode, fastMode */
+    {{0, 0, 5}},                /* 0 : base, symbol, bits */
+    {{0, 6, 4}},
+    {{0, 9, 5}},
+    {{0, 15, 5}},
+    {{0, 21, 5}},
+    {{0, 3, 5}},
+    {{0, 7, 4}},
+    {{0, 12, 5}},
+    {{0, 18, 5}},
+    {{0, 23, 5}},
+    {{0, 5, 5}},
+    {{0, 8, 4}},
+    {{0, 14, 5}},
+    {{0, 20, 5}},
+    {{0, 2, 5}},
+    {{16, 7, 4}},
+    {{0, 11, 5}},
+    {{0, 17, 5}},
+    {{0, 22, 5}},
+    {{0, 4, 5}},
+    {{16, 8, 4}},
+    {{0, 13, 5}},
+    {{0, 19, 5}},
+    {{0, 1, 5}},
+    {{16, 6, 4}},
+    {{0, 10, 5}},
+    {{0, 16, 5}},
+    {{0, 28, 5}},
+    {{0, 27, 5}},
+    {{0, 26, 5}},
+    {{0, 25, 5}},
+    {{0, 24, 5}},
+}; /* OF_defaultDTable */
+
+/*! ZSTD_buildSeqTable() :
+       @return : nb bytes read from src,
+                         or an error code if it fails, testable with 
ZSTD_isError()
+*/
+static size_t ZSTD_buildSeqTable(FSE_DTable *DTableSpace, const FSE_DTable 
**DTablePtr, symbolEncodingType_e type, U32 max, U32 maxLog, const void *src,
+                                size_t srcSize, const FSE_decode_t4 
*defaultTable, U32 flagRepeatTable, void *workspace, size_t workspaceSize)
+{
+       const void *const tmpPtr = defaultTable; /* bypass strict aliasing */
+       switch (type) {
+       case set_rle:
+               if (!srcSize)
+                       return ERROR(srcSize_wrong);
+               if ((*(const BYTE *)src) > max)
+                       return ERROR(corruption_detected);
+               FSE_buildDTable_rle(DTableSpace, *(const BYTE *)src);
+               *DTablePtr = DTableSpace;
+               return 1;
+       case set_basic: *DTablePtr = (const FSE_DTable *)tmpPtr; return 0;
+       case set_repeat:
+               if (!flagRepeatTable)
+                       return ERROR(corruption_detected);
+               return 0;
+       default: /* impossible */
+       case set_compressed: {
+               U32 tableLog;
+               S16 *norm = (S16 *)workspace;
+               size_t const spaceUsed32 = ALIGN(sizeof(S16) * (MaxSeq + 1), 
sizeof(U32)) >> 2;
+
+               if ((spaceUsed32 << 2) > workspaceSize)
+                       return ERROR(GENERIC);
+               workspace = (U32 *)workspace + spaceUsed32;
+               workspaceSize -= (spaceUsed32 << 2);
+               {
+                       size_t const headerSize = FSE_readNCount(norm, &max, 
&tableLog, src, srcSize);
+                       if (FSE_isError(headerSize))
+                               return ERROR(corruption_detected);
+                       if (tableLog > maxLog)
+                               return ERROR(corruption_detected);
+                       FSE_buildDTable_wksp(DTableSpace, norm, max, tableLog, 
workspace, workspaceSize);
+                       *DTablePtr = DTableSpace;
+                       return headerSize;
+               }
+       }
+       }
+}
+
+size_t ZSTD_decodeSeqHeaders(ZSTD_DCtx *dctx, int *nbSeqPtr, const void *src, 
size_t srcSize)
+{
+       const BYTE *const istart = (const BYTE *const)src;
+       const BYTE *const iend = istart + srcSize;
+       const BYTE *ip = istart;
+
+       /* check */
+       if (srcSize < MIN_SEQUENCES_SIZE)
+               return ERROR(srcSize_wrong);
+
+       /* SeqHead */
+       {
+               int nbSeq = *ip++;
+               if (!nbSeq) {
+                       *nbSeqPtr = 0;
+                       return 1;
+               }
+               if (nbSeq > 0x7F) {
+                       if (nbSeq == 0xFF) {
+                               if (ip + 2 > iend)
+                                       return ERROR(srcSize_wrong);
+                               nbSeq = ZSTD_readLE16(ip) + LONGNBSEQ, ip += 2;
+                       } else {
+                               if (ip >= iend)
+                                       return ERROR(srcSize_wrong);
+                               nbSeq = ((nbSeq - 0x80) << 8) + *ip++;
+                       }
+               }
+               *nbSeqPtr = nbSeq;
+       }
+
+       /* FSE table descriptors */
+       if (ip + 4 > iend)
+               return ERROR(srcSize_wrong); /* minimum possible size */
+       {
+               symbolEncodingType_e const LLtype = (symbolEncodingType_e)(*ip 
>> 6);
+               symbolEncodingType_e const OFtype = (symbolEncodingType_e)((*ip 
>> 4) & 3);
+               symbolEncodingType_e const MLtype = (symbolEncodingType_e)((*ip 
>> 2) & 3);
+               ip++;
+
+               /* Build DTables */
+               {
+                       size_t const llhSize = 
ZSTD_buildSeqTable(dctx->entropy.LLTable, &dctx->LLTptr, LLtype, MaxLL, 
LLFSELog, ip, iend - ip,
+                                                                 
LL_defaultDTable, dctx->fseEntropy, dctx->entropy.workspace, 
sizeof(dctx->entropy.workspace));
+                       if (ZSTD_isError(llhSize))
+                               return ERROR(corruption_detected);
+                       ip += llhSize;
+               }
+               {
+                       size_t const ofhSize = 
ZSTD_buildSeqTable(dctx->entropy.OFTable, &dctx->OFTptr, OFtype, MaxOff, 
OffFSELog, ip, iend - ip,
+                                                                 
OF_defaultDTable, dctx->fseEntropy, dctx->entropy.workspace, 
sizeof(dctx->entropy.workspace));
+                       if (ZSTD_isError(ofhSize))
+                               return ERROR(corruption_detected);
+                       ip += ofhSize;
+               }
+               {
+                       size_t const mlhSize = 
ZSTD_buildSeqTable(dctx->entropy.MLTable, &dctx->MLTptr, MLtype, MaxML, 
MLFSELog, ip, iend - ip,
+                                                                 
ML_defaultDTable, dctx->fseEntropy, dctx->entropy.workspace, 
sizeof(dctx->entropy.workspace));
+                       if (ZSTD_isError(mlhSize))
+                               return ERROR(corruption_detected);
+                       ip += mlhSize;
+               }
+       }
+
+       return ip - istart;
+}
+
+typedef struct {
+       size_t litLength;
+       size_t matchLength;
+       size_t offset;
+       const BYTE *match;
+} seq_t;
+
+typedef struct {
+       BIT_DStream_t DStream;
+       FSE_DState_t stateLL;
+       FSE_DState_t stateOffb;
+       FSE_DState_t stateML;
+       size_t prevOffset[ZSTD_REP_NUM];
+       const BYTE *base;
+       size_t pos;
+       uPtrDiff gotoDict;
+} seqState_t;
+
+FORCE_NOINLINE
+size_t ZSTD_execSequenceLast7(BYTE *op, BYTE *const oend, seq_t sequence, 
const BYTE **litPtr, const BYTE *const litLimit, const BYTE *const base,
+                             const BYTE *const vBase, const BYTE *const 
dictEnd)
+{
+       BYTE *const oLitEnd = op + sequence.litLength;
+       size_t const sequenceLength = sequence.litLength + sequence.matchLength;
+       BYTE *const oMatchEnd = op + sequenceLength; /* risk : address space 
overflow (32-bits) */
+       BYTE *const oend_w = oend - WILDCOPY_OVERLENGTH;
+       const BYTE *const iLitEnd = *litPtr + sequence.litLength;
+       const BYTE *match = oLitEnd - sequence.offset;
+
+       /* check */
+       if (oMatchEnd > oend)
+               return ERROR(dstSize_tooSmall); /* last match must start at a 
minimum distance of WILDCOPY_OVERLENGTH from oend */
+       if (iLitEnd > litLimit)
+               return ERROR(corruption_detected); /* over-read beyond lit 
buffer */
+       if (oLitEnd <= oend_w)
+               return ERROR(GENERIC); /* Precondition */
+
+       /* copy literals */
+       if (op < oend_w) {
+               ZSTD_wildcopy(op, *litPtr, oend_w - op);
+               *litPtr += oend_w - op;
+               op = oend_w;
+       }
+       while (op < oLitEnd)
+               *op++ = *(*litPtr)++;
+
+       /* copy Match */
+       if (sequence.offset > (size_t)(oLitEnd - base)) {
+               /* offset beyond prefix */
+               if (sequence.offset > (size_t)(oLitEnd - vBase))
+                       return ERROR(corruption_detected);
+               match = dictEnd - (base - match);
+               if (match + sequence.matchLength <= dictEnd) {
+                       memmove(oLitEnd, match, sequence.matchLength);
+                       return sequenceLength;
+               }
+               /* span extDict & currPrefixSegment */
+               {
+                       size_t const length1 = dictEnd - match;
+                       memmove(oLitEnd, match, length1);
+                       op = oLitEnd + length1;
+                       sequence.matchLength -= length1;
+                       match = base;
+               }
+       }
+       while (op < oMatchEnd)
+               *op++ = *match++;
+       return sequenceLength;
+}
+
+static seq_t ZSTD_decodeSequence(seqState_t *seqState)
+{
+       seq_t seq;
+
+       U32 const llCode = FSE_peekSymbol(&seqState->stateLL);
+       U32 const mlCode = FSE_peekSymbol(&seqState->stateML);
+       U32 const ofCode = FSE_peekSymbol(&seqState->stateOffb); /* <= maxOff, 
by table construction */
+
+       U32 const llBits = LL_bits[llCode];
+       U32 const mlBits = ML_bits[mlCode];
+       U32 const ofBits = ofCode;
+       U32 const totalBits = llBits + mlBits + ofBits;
+
+       static const U32 LL_base[MaxLL + 1] = {0,  1,  2,  3,  4,  5,  6,  7,  
8,    9,     10,    11,    12,    13,     14,     15,     16,     18,
+                                              20, 22, 24, 28, 32, 40, 48, 64, 
0x80, 0x100, 0x200, 0x400, 0x800, 0x1000, 0x2000, 0x4000, 0x8000, 0x10000};
+
+       static const U32 ML_base[MaxML + 1] = {3,  4,  5,  6,  7,  8,  9,  10,  
 11,    12,    13,    14,    15,     16,     17,     18,     19,     20,
+                                              21, 22, 23, 24, 25, 26, 27, 28,  
 29,    30,    31,    32,    33,     34,     35,     37,     39,     41,
+                                              43, 47, 51, 59, 67, 83, 99, 
0x83, 0x103, 0x203, 0x403, 0x803, 0x1003, 0x2003, 0x4003, 0x8003, 0x10003};
+
+       static const U32 OF_base[MaxOff + 1] = {0,       1,     1,      5,      
0xD,      0x1D,      0x3D,      0x7D,      0xFD,     0x1FD,
+                                               0x3FD,   0x7FD,    0xFFD,    
0x1FFD,   0x3FFD,   0x7FFD,    0xFFFD,    0x1FFFD,   0x3FFFD,  0x7FFFD,
+                                               0xFFFFD, 0x1FFFFD, 0x3FFFFD, 
0x7FFFFD, 0xFFFFFD, 0x1FFFFFD, 0x3FFFFFD, 0x7FFFFFD, 0xFFFFFFD};
+
+       /* sequence */
+       {
+               size_t offset;
+               if (!ofCode)
+                       offset = 0;
+               else {
+                       offset = OF_base[ofCode] + 
BIT_readBitsFast(&seqState->DStream, ofBits); /* <=  (ZSTD_WINDOWLOG_MAX-1) 
bits */
+                       if (ZSTD_32bits())
+                               BIT_reloadDStream(&seqState->DStream);
+               }
+
+               if (ofCode <= 1) {
+                       offset += (llCode == 0);
+                       if (offset) {
+                               size_t temp = (offset == 3) ? 
seqState->prevOffset[0] - 1 : seqState->prevOffset[offset];
+                               temp += !temp; /* 0 is not valid; input is 
corrupted; force offset to 1 */
+                               if (offset != 1)
+                                       seqState->prevOffset[2] = 
seqState->prevOffset[1];
+                               seqState->prevOffset[1] = 
seqState->prevOffset[0];
+                               seqState->prevOffset[0] = offset = temp;
+                       } else {
+                               offset = seqState->prevOffset[0];
+                       }
+               } else {
+                       seqState->prevOffset[2] = seqState->prevOffset[1];
+                       seqState->prevOffset[1] = seqState->prevOffset[0];
+                       seqState->prevOffset[0] = offset;
+               }
+               seq.offset = offset;
+       }
+
+       seq.matchLength = ML_base[mlCode] + ((mlCode > 31) ? 
BIT_readBitsFast(&seqState->DStream, mlBits) : 0); /* <=  16 bits */
+       if (ZSTD_32bits() && (mlBits + llBits > 24))
+               BIT_reloadDStream(&seqState->DStream);
+
+       seq.litLength = LL_base[llCode] + ((llCode > 15) ? 
BIT_readBitsFast(&seqState->DStream, llBits) : 0); /* <=  16 bits */
+       if (ZSTD_32bits() || (totalBits > 64 - 7 - (LLFSELog + MLFSELog + 
OffFSELog)))
+               BIT_reloadDStream(&seqState->DStream);
+
+       /* ANS state update */
+       FSE_updateState(&seqState->stateLL, &seqState->DStream); /* <=  9 bits 
*/
+       FSE_updateState(&seqState->stateML, &seqState->DStream); /* <=  9 bits 
*/
+       if (ZSTD_32bits())
+               BIT_reloadDStream(&seqState->DStream);             /* <= 18 
bits */
+       FSE_updateState(&seqState->stateOffb, &seqState->DStream); /* <=  8 
bits */
+
+       seq.match = NULL;
+
+       return seq;
+}
+
+FORCE_INLINE
+size_t ZSTD_execSequence(BYTE *op, BYTE *const oend, seq_t sequence, const 
BYTE **litPtr, const BYTE *const litLimit, const BYTE *const base,
+                        const BYTE *const vBase, const BYTE *const dictEnd)
+{
+       BYTE *const oLitEnd = op + sequence.litLength;
+       size_t const sequenceLength = sequence.litLength + sequence.matchLength;
+       BYTE *const oMatchEnd = op + sequenceLength; /* risk : address space 
overflow (32-bits) */
+       BYTE *const oend_w = oend - WILDCOPY_OVERLENGTH;
+       const BYTE *const iLitEnd = *litPtr + sequence.litLength;
+       const BYTE *match = oLitEnd - sequence.offset;
+
+       /* check */
+       if (oMatchEnd > oend)
+               return ERROR(dstSize_tooSmall); /* last match must start at a 
minimum distance of WILDCOPY_OVERLENGTH from oend */
+       if (iLitEnd > litLimit)
+               return ERROR(corruption_detected); /* over-read beyond lit 
buffer */
+       if (oLitEnd > oend_w)
+               return ZSTD_execSequenceLast7(op, oend, sequence, litPtr, 
litLimit, base, vBase, dictEnd);
+
+       /* copy Literals */
+       ZSTD_copy8(op, *litPtr);
+       if (sequence.litLength > 8)
+               ZSTD_wildcopy(op + 8, (*litPtr) + 8,
+                             sequence.litLength - 8); /* note : since oLitEnd 
<= oend-WILDCOPY_OVERLENGTH, no risk of overwrite beyond oend */
+       op = oLitEnd;
+       *litPtr = iLitEnd; /* update for next sequence */
+
+       /* copy Match */
+       if (sequence.offset > (size_t)(oLitEnd - base)) {
+               /* offset beyond prefix */
+               if (sequence.offset > (size_t)(oLitEnd - vBase))
+                       return ERROR(corruption_detected);
+               match = dictEnd + (match - base);
+               if (match + sequence.matchLength <= dictEnd) {
+                       memmove(oLitEnd, match, sequence.matchLength);
+                       return sequenceLength;
+               }
+               /* span extDict & currPrefixSegment */
+               {
+                       size_t const length1 = dictEnd - match;
+                       memmove(oLitEnd, match, length1);
+                       op = oLitEnd + length1;
+                       sequence.matchLength -= length1;
+                       match = base;
+                       if (op > oend_w || sequence.matchLength < MINMATCH) {
+                               U32 i;
+                               for (i = 0; i < sequence.matchLength; ++i)
+                                       op[i] = match[i];
+                               return sequenceLength;
+                       }
+               }
+       }
+       /* Requirement: op <= oend_w && sequence.matchLength >= MINMATCH */
+
+       /* match within prefix */
+       if (sequence.offset < 8) {
+               /* close range match, overlap */
+               static const U32 dec32table[] = {0, 1, 2, 1, 4, 4, 4, 4};   /* 
added */
+               static const int dec64table[] = {8, 8, 8, 7, 8, 9, 10, 11}; /* 
subtracted */
+               int const sub2 = dec64table[sequence.offset];
+               op[0] = match[0];
+               op[1] = match[1];
+               op[2] = match[2];
+               op[3] = match[3];
+               match += dec32table[sequence.offset];
+               ZSTD_copy4(op + 4, match);
+               match -= sub2;
+       } else {
+               ZSTD_copy8(op, match);
+       }
+       op += 8;
+       match += 8;
+
+       if (oMatchEnd > oend - (16 - MINMATCH)) {
+               if (op < oend_w) {
+                       ZSTD_wildcopy(op, match, oend_w - op);
+                       match += oend_w - op;
+                       op = oend_w;
+               }
+               while (op < oMatchEnd)
+                       *op++ = *match++;
+       } else {
+               ZSTD_wildcopy(op, match, (ptrdiff_t)sequence.matchLength - 8); 
/* works even if matchLength < 8 */
+       }
+       return sequenceLength;
+}
+
+static size_t ZSTD_decompressSequences(ZSTD_DCtx *dctx, void *dst, size_t 
maxDstSize, const void *seqStart, size_t seqSize)
+{
+       const BYTE *ip = (const BYTE *)seqStart;
+       const BYTE *const iend = ip + seqSize;
+       BYTE *const ostart = (BYTE * const)dst;
+       BYTE *const oend = ostart + maxDstSize;
+       BYTE *op = ostart;
+       const BYTE *litPtr = dctx->litPtr;
+       const BYTE *const litEnd = litPtr + dctx->litSize;
+       const BYTE *const base = (const BYTE *)(dctx->base);
+       const BYTE *const vBase = (const BYTE *)(dctx->vBase);
+       const BYTE *const dictEnd = (const BYTE *)(dctx->dictEnd);
+       int nbSeq;
+
+       /* Build Decoding Tables */
+       {
+               size_t const seqHSize = ZSTD_decodeSeqHeaders(dctx, &nbSeq, ip, 
seqSize);
+               if (ZSTD_isError(seqHSize))
+                       return seqHSize;
+               ip += seqHSize;
+       }
+
+       /* Regen sequences */
+       if (nbSeq) {
+               seqState_t seqState;
+               dctx->fseEntropy = 1;
+               {
+                       U32 i;
+                       for (i = 0; i < ZSTD_REP_NUM; i++)
+                               seqState.prevOffset[i] = dctx->entropy.rep[i];
+               }
+               CHECK_E(BIT_initDStream(&seqState.DStream, ip, iend - ip), 
corruption_detected);
+               FSE_initDState(&seqState.stateLL, &seqState.DStream, 
dctx->LLTptr);
+               FSE_initDState(&seqState.stateOffb, &seqState.DStream, 
dctx->OFTptr);
+               FSE_initDState(&seqState.stateML, &seqState.DStream, 
dctx->MLTptr);
+
+               for (; (BIT_reloadDStream(&(seqState.DStream)) <= 
BIT_DStream_completed) && nbSeq;) {
+                       nbSeq--;
+                       {
+                               seq_t const sequence = 
ZSTD_decodeSequence(&seqState);
+                               size_t const oneSeqSize = ZSTD_execSequence(op, 
oend, sequence, &litPtr, litEnd, base, vBase, dictEnd);
+                               if (ZSTD_isError(oneSeqSize))
+                                       return oneSeqSize;
+                               op += oneSeqSize;
+                       }
+               }
+
+               /* check if reached exact end */
+               if (nbSeq)
+                       return ERROR(corruption_detected);
+               /* save reps for next block */
+               {
+                       U32 i;
+                       for (i = 0; i < ZSTD_REP_NUM; i++)
+                               dctx->entropy.rep[i] = 
(U32)(seqState.prevOffset[i]);
+               }
+       }
+
+       /* last literal segment */
+       {
+               size_t const lastLLSize = litEnd - litPtr;
+               if (lastLLSize > (size_t)(oend - op))
+                       return ERROR(dstSize_tooSmall);
+               memcpy(op, litPtr, lastLLSize);
+               op += lastLLSize;
+       }
+
+       return op - ostart;
+}
+
+FORCE_INLINE seq_t ZSTD_decodeSequenceLong_generic(seqState_t *seqState, int 
const longOffsets)
+{
+       seq_t seq;
+
+       U32 const llCode = FSE_peekSymbol(&seqState->stateLL);
+       U32 const mlCode = FSE_peekSymbol(&seqState->stateML);
+       U32 const ofCode = FSE_peekSymbol(&seqState->stateOffb); /* <= maxOff, 
by table construction */
+
+       U32 const llBits = LL_bits[llCode];
+       U32 const mlBits = ML_bits[mlCode];
+       U32 const ofBits = ofCode;
+       U32 const totalBits = llBits + mlBits + ofBits;
+
+       static const U32 LL_base[MaxLL + 1] = {0,  1,  2,  3,  4,  5,  6,  7,  
8,    9,     10,    11,    12,    13,     14,     15,     16,     18,
+                                              20, 22, 24, 28, 32, 40, 48, 64, 
0x80, 0x100, 0x200, 0x400, 0x800, 0x1000, 0x2000, 0x4000, 0x8000, 0x10000};
+
+       static const U32 ML_base[MaxML + 1] = {3,  4,  5,  6,  7,  8,  9,  10,  
 11,    12,    13,    14,    15,     16,     17,     18,     19,     20,
+                                              21, 22, 23, 24, 25, 26, 27, 28,  
 29,    30,    31,    32,    33,     34,     35,     37,     39,     41,
+                                              43, 47, 51, 59, 67, 83, 99, 
0x83, 0x103, 0x203, 0x403, 0x803, 0x1003, 0x2003, 0x4003, 0x8003, 0x10003};
+
+       static const U32 OF_base[MaxOff + 1] = {0,       1,     1,      5,      
0xD,      0x1D,      0x3D,      0x7D,      0xFD,     0x1FD,
+                                               0x3FD,   0x7FD,    0xFFD,    
0x1FFD,   0x3FFD,   0x7FFD,    0xFFFD,    0x1FFFD,   0x3FFFD,  0x7FFFD,
+                                               0xFFFFD, 0x1FFFFD, 0x3FFFFD, 
0x7FFFFD, 0xFFFFFD, 0x1FFFFFD, 0x3FFFFFD, 0x7FFFFFD, 0xFFFFFFD};
+
+       /* sequence */
+       {
+               size_t offset;
+               if (!ofCode)
+                       offset = 0;
+               else {
+                       if (longOffsets) {
+                               int const extraBits = ofBits - MIN(ofBits, 
STREAM_ACCUMULATOR_MIN);
+                               offset = OF_base[ofCode] + 
(BIT_readBitsFast(&seqState->DStream, ofBits - extraBits) << extraBits);
+                               if (ZSTD_32bits() || extraBits)
+                                       BIT_reloadDStream(&seqState->DStream);
+                               if (extraBits)
+                                       offset += 
BIT_readBitsFast(&seqState->DStream, extraBits);
+                       } else {
+                               offset = OF_base[ofCode] + 
BIT_readBitsFast(&seqState->DStream, ofBits); /* <=  (ZSTD_WINDOWLOG_MAX-1) 
bits */
+                               if (ZSTD_32bits())
+                                       BIT_reloadDStream(&seqState->DStream);
+                       }
+               }
+
+               if (ofCode <= 1) {
+                       offset += (llCode == 0);
+                       if (offset) {
+                               size_t temp = (offset == 3) ? 
seqState->prevOffset[0] - 1 : seqState->prevOffset[offset];
+                               temp += !temp; /* 0 is not valid; input is 
corrupted; force offset to 1 */
+                               if (offset != 1)
+                                       seqState->prevOffset[2] = 
seqState->prevOffset[1];
+                               seqState->prevOffset[1] = 
seqState->prevOffset[0];
+                               seqState->prevOffset[0] = offset = temp;
+                       } else {
+                               offset = seqState->prevOffset[0];
+                       }
+               } else {
+                       seqState->prevOffset[2] = seqState->prevOffset[1];
+                       seqState->prevOffset[1] = seqState->prevOffset[0];
+                       seqState->prevOffset[0] = offset;
+               }
+               seq.offset = offset;
+       }
+
+       seq.matchLength = ML_base[mlCode] + ((mlCode > 31) ? 
BIT_readBitsFast(&seqState->DStream, mlBits) : 0); /* <=  16 bits */
+       if (ZSTD_32bits() && (mlBits + llBits > 24))
+               BIT_reloadDStream(&seqState->DStream);
+
+       seq.litLength = LL_base[llCode] + ((llCode > 15) ? 
BIT_readBitsFast(&seqState->DStream, llBits) : 0); /* <=  16 bits */
+       if (ZSTD_32bits() || (totalBits > 64 - 7 - (LLFSELog + MLFSELog + 
OffFSELog)))
+               BIT_reloadDStream(&seqState->DStream);
+
+       {
+               size_t const pos = seqState->pos + seq.litLength;
+               seq.match = seqState->base + pos - seq.offset; /* single memory 
segment */
+               if (seq.offset > pos)
+                       seq.match += seqState->gotoDict; /* separate memory 
segment */
+               seqState->pos = pos + seq.matchLength;
+       }
+
+       /* ANS state update */
+       FSE_updateState(&seqState->stateLL, &seqState->DStream); /* <=  9 bits 
*/
+       FSE_updateState(&seqState->stateML, &seqState->DStream); /* <=  9 bits 
*/
+       if (ZSTD_32bits())
+               BIT_reloadDStream(&seqState->DStream);             /* <= 18 
bits */
+       FSE_updateState(&seqState->stateOffb, &seqState->DStream); /* <=  8 
bits */
+
+       return seq;
+}
+
+static seq_t ZSTD_decodeSequenceLong(seqState_t *seqState, unsigned const 
windowSize)
+{
+       if (ZSTD_highbit32(windowSize) > STREAM_ACCUMULATOR_MIN) {
+               return ZSTD_decodeSequenceLong_generic(seqState, 1);
+       } else {
+               return ZSTD_decodeSequenceLong_generic(seqState, 0);
+       }
+}
+
+FORCE_INLINE
+size_t ZSTD_execSequenceLong(BYTE *op, BYTE *const oend, seq_t sequence, const 
BYTE **litPtr, const BYTE *const litLimit, const BYTE *const base,
+                            const BYTE *const vBase, const BYTE *const dictEnd)
+{
+       BYTE *const oLitEnd = op + sequence.litLength;
+       size_t const sequenceLength = sequence.litLength + sequence.matchLength;
+       BYTE *const oMatchEnd = op + sequenceLength; /* risk : address space 
overflow (32-bits) */
+       BYTE *const oend_w = oend - WILDCOPY_OVERLENGTH;
+       const BYTE *const iLitEnd = *litPtr + sequence.litLength;
+       const BYTE *match = sequence.match;
+
+       /* check */
+       if (oMatchEnd > oend)
+               return ERROR(dstSize_tooSmall); /* last match must start at a 
minimum distance of WILDCOPY_OVERLENGTH from oend */
+       if (iLitEnd > litLimit)
+               return ERROR(corruption_detected); /* over-read beyond lit 
buffer */
+       if (oLitEnd > oend_w)
+               return ZSTD_execSequenceLast7(op, oend, sequence, litPtr, 
litLimit, base, vBase, dictEnd);
+
+       /* copy Literals */
+       ZSTD_copy8(op, *litPtr);
+       if (sequence.litLength > 8)
+               ZSTD_wildcopy(op + 8, (*litPtr) + 8,
+                             sequence.litLength - 8); /* note : since oLitEnd 
<= oend-WILDCOPY_OVERLENGTH, no risk of overwrite beyond oend */
+       op = oLitEnd;
+       *litPtr = iLitEnd; /* update for next sequence */
+
+       /* copy Match */
+       if (sequence.offset > (size_t)(oLitEnd - base)) {
+               /* offset beyond prefix */
+               if (sequence.offset > (size_t)(oLitEnd - vBase))
+                       return ERROR(corruption_detected);
+               if (match + sequence.matchLength <= dictEnd) {
+                       memmove(oLitEnd, match, sequence.matchLength);
+                       return sequenceLength;
+               }
+               /* span extDict & currPrefixSegment */
+               {
+                       size_t const length1 = dictEnd - match;
+                       memmove(oLitEnd, match, length1);
+                       op = oLitEnd + length1;
+                       sequence.matchLength -= length1;
+                       match = base;
+                       if (op > oend_w || sequence.matchLength < MINMATCH) {
+                               U32 i;
+                               for (i = 0; i < sequence.matchLength; ++i)
+                                       op[i] = match[i];
+                               return sequenceLength;
+                       }
+               }
+       }
+       /* Requirement: op <= oend_w && sequence.matchLength >= MINMATCH */
+
+       /* match within prefix */
+       if (sequence.offset < 8) {
+               /* close range match, overlap */
+               static const U32 dec32table[] = {0, 1, 2, 1, 4, 4, 4, 4};   /* 
added */
+               static const int dec64table[] = {8, 8, 8, 7, 8, 9, 10, 11}; /* 
subtracted */
+               int const sub2 = dec64table[sequence.offset];
+               op[0] = match[0];
+               op[1] = match[1];
+               op[2] = match[2];
+               op[3] = match[3];
+               match += dec32table[sequence.offset];
+               ZSTD_copy4(op + 4, match);
+               match -= sub2;
+       } else {
+               ZSTD_copy8(op, match);
+       }
+       op += 8;
+       match += 8;
+
+       if (oMatchEnd > oend - (16 - MINMATCH)) {
+               if (op < oend_w) {
+                       ZSTD_wildcopy(op, match, oend_w - op);
+                       match += oend_w - op;
+                       op = oend_w;
+               }
+               while (op < oMatchEnd)
+                       *op++ = *match++;
+       } else {
+               ZSTD_wildcopy(op, match, (ptrdiff_t)sequence.matchLength - 8); 
/* works even if matchLength < 8 */
+       }
+       return sequenceLength;
+}
+
+static size_t ZSTD_decompressSequencesLong(ZSTD_DCtx *dctx, void *dst, size_t 
maxDstSize, const void *seqStart, size_t seqSize)
+{
+       const BYTE *ip = (const BYTE *)seqStart;
+       const BYTE *const iend = ip + seqSize;
+       BYTE *const ostart = (BYTE * const)dst;
+       BYTE *const oend = ostart + maxDstSize;
+       BYTE *op = ostart;
+       const BYTE *litPtr = dctx->litPtr;
+       const BYTE *const litEnd = litPtr + dctx->litSize;
+       const BYTE *const base = (const BYTE *)(dctx->base);
+       const BYTE *const vBase = (const BYTE *)(dctx->vBase);
+       const BYTE *const dictEnd = (const BYTE *)(dctx->dictEnd);
+       unsigned const windowSize = dctx->fParams.windowSize;
+       int nbSeq;
+
+       /* Build Decoding Tables */
+       {
+               size_t const seqHSize = ZSTD_decodeSeqHeaders(dctx, &nbSeq, ip, 
seqSize);
+               if (ZSTD_isError(seqHSize))
+                       return seqHSize;
+               ip += seqHSize;
+       }
+
+       /* Regen sequences */
+       if (nbSeq) {
+#define STORED_SEQS 4
+#define STOSEQ_MASK (STORED_SEQS - 1)
+#define ADVANCED_SEQS 4
+               seq_t *sequences = (seq_t *)dctx->entropy.workspace;
+               int const seqAdvance = MIN(nbSeq, ADVANCED_SEQS);
+               seqState_t seqState;
+               int seqNb;
+               ZSTD_STATIC_ASSERT(sizeof(dctx->entropy.workspace) >= 
sizeof(seq_t) * STORED_SEQS);
+               dctx->fseEntropy = 1;
+               {
+                       U32 i;
+                       for (i = 0; i < ZSTD_REP_NUM; i++)
+                               seqState.prevOffset[i] = dctx->entropy.rep[i];
+               }
+               seqState.base = base;
+               seqState.pos = (size_t)(op - base);
+               seqState.gotoDict = (uPtrDiff)dictEnd - (uPtrDiff)base; /* cast 
to avoid undefined behaviour */
+               CHECK_E(BIT_initDStream(&seqState.DStream, ip, iend - ip), 
corruption_detected);
+               FSE_initDState(&seqState.stateLL, &seqState.DStream, 
dctx->LLTptr);
+               FSE_initDState(&seqState.stateOffb, &seqState.DStream, 
dctx->OFTptr);
+               FSE_initDState(&seqState.stateML, &seqState.DStream, 
dctx->MLTptr);
+
+               /* prepare in advance */
+               for (seqNb = 0; (BIT_reloadDStream(&seqState.DStream) <= 
BIT_DStream_completed) && seqNb < seqAdvance; seqNb++) {
+                       sequences[seqNb] = ZSTD_decodeSequenceLong(&seqState, 
windowSize);
+               }
+               if (seqNb < seqAdvance)
+                       return ERROR(corruption_detected);
+
+               /* decode and decompress */
+               for (; (BIT_reloadDStream(&(seqState.DStream)) <= 
BIT_DStream_completed) && seqNb < nbSeq; seqNb++) {
+                       seq_t const sequence = 
ZSTD_decodeSequenceLong(&seqState, windowSize);
+                       size_t const oneSeqSize =
+                           ZSTD_execSequenceLong(op, oend, sequences[(seqNb - 
ADVANCED_SEQS) & STOSEQ_MASK], &litPtr, litEnd, base, vBase, dictEnd);
+                       if (ZSTD_isError(oneSeqSize))
+                               return oneSeqSize;
+                       ZSTD_PREFETCH(sequence.match);
+                       sequences[seqNb & STOSEQ_MASK] = sequence;
+                       op += oneSeqSize;
+               }
+               if (seqNb < nbSeq)
+                       return ERROR(corruption_detected);
+
+               /* finish queue */
+               seqNb -= seqAdvance;
+               for (; seqNb < nbSeq; seqNb++) {
+                       size_t const oneSeqSize = ZSTD_execSequenceLong(op, 
oend, sequences[seqNb & STOSEQ_MASK], &litPtr, litEnd, base, vBase, dictEnd);
+                       if (ZSTD_isError(oneSeqSize))
+                               return oneSeqSize;
+                       op += oneSeqSize;
+               }
+
+               /* save reps for next block */
+               {
+                       U32 i;
+                       for (i = 0; i < ZSTD_REP_NUM; i++)
+                               dctx->entropy.rep[i] = 
(U32)(seqState.prevOffset[i]);
+               }
+       }
+
+       /* last literal segment */
+       {
+               size_t const lastLLSize = litEnd - litPtr;
+               if (lastLLSize > (size_t)(oend - op))
+                       return ERROR(dstSize_tooSmall);
+               memcpy(op, litPtr, lastLLSize);
+               op += lastLLSize;
+       }
+
+       return op - ostart;
+}
+
+static size_t ZSTD_decompressBlock_internal(ZSTD_DCtx *dctx, void *dst, size_t 
dstCapacity, const void *src, size_t srcSize)
+{ /* blockType == blockCompressed */
+       const BYTE *ip = (const BYTE *)src;
+
+       if (srcSize >= ZSTD_BLOCKSIZE_ABSOLUTEMAX)
+               return ERROR(srcSize_wrong);
+
+       /* Decode literals section */
+       {
+               size_t const litCSize = ZSTD_decodeLiteralsBlock(dctx, src, 
srcSize);
+               if (ZSTD_isError(litCSize))
+                       return litCSize;
+               ip += litCSize;
+               srcSize -= litCSize;
+       }
+       if (sizeof(size_t) > 4) /* do not enable prefetching on 32-bits x86, as 
it's performance detrimental */
+                               /* likely because of register pressure */
+                               /* if that's the correct cause, then 32-bits 
ARM should be affected differently */
+                               /* it would be good to test this on ARM real 
hardware, to see if prefetch version improves speed */
+               if (dctx->fParams.windowSize > (1 << 23))
+                       return ZSTD_decompressSequencesLong(dctx, dst, 
dstCapacity, ip, srcSize);
+       return ZSTD_decompressSequences(dctx, dst, dstCapacity, ip, srcSize);
+}
+
+static void ZSTD_checkContinuity(ZSTD_DCtx *dctx, const void *dst)
+{
+       if (dst != dctx->previousDstEnd) { /* not contiguous */
+               dctx->dictEnd = dctx->previousDstEnd;
+               dctx->vBase = (const char *)dst - ((const char 
*)(dctx->previousDstEnd) - (const char *)(dctx->base));
+               dctx->base = dst;
+               dctx->previousDstEnd = dst;
+       }
+}
+
+size_t ZSTD_decompressBlock(ZSTD_DCtx *dctx, void *dst, size_t dstCapacity, 
const void *src, size_t srcSize)
+{
+       size_t dSize;
+       ZSTD_checkContinuity(dctx, dst);
+       dSize = ZSTD_decompressBlock_internal(dctx, dst, dstCapacity, src, 
srcSize);
+       dctx->previousDstEnd = (char *)dst + dSize;
+       return dSize;
+}
+
+/** ZSTD_insertBlock() :
+       insert `src` block into `dctx` history. Useful to track uncompressed 
blocks. */
+size_t ZSTD_insertBlock(ZSTD_DCtx *dctx, const void *blockStart, size_t 
blockSize)
+{
+       ZSTD_checkContinuity(dctx, blockStart);
+       dctx->previousDstEnd = (const char *)blockStart + blockSize;
+       return blockSize;
+}
+
+size_t ZSTD_generateNxBytes(void *dst, size_t dstCapacity, BYTE byte, size_t 
length)
+{
+       if (length > dstCapacity)
+               return ERROR(dstSize_tooSmall);
+       memset(dst, byte, length);
+       return length;
+}
+
+/** ZSTD_findFrameCompressedSize() :
+ *  compatible with legacy mode
+ *  `src` must point to the start of a ZSTD frame, ZSTD legacy frame, or 
skippable frame
+ *  `srcSize` must be at least as large as the frame contained
+ *  @return : the compressed size of the frame starting at `src` */
+size_t ZSTD_findFrameCompressedSize(const void *src, size_t srcSize)
+{
+       if (srcSize >= ZSTD_skippableHeaderSize && (ZSTD_readLE32(src) & 
0xFFFFFFF0U) == ZSTD_MAGIC_SKIPPABLE_START) {
+               return ZSTD_skippableHeaderSize + ZSTD_readLE32((const BYTE 
*)src + 4);
+       } else {
+               const BYTE *ip = (const BYTE *)src;
+               const BYTE *const ipstart = ip;
+               size_t remainingSize = srcSize;
+               ZSTD_frameParams fParams;
+
+               size_t const headerSize = ZSTD_frameHeaderSize(ip, 
remainingSize);
+               if (ZSTD_isError(headerSize))
+                       return headerSize;
+
+               /* Frame Header */
+               {
+                       size_t const ret = ZSTD_getFrameParams(&fParams, ip, 
remainingSize);
+                       if (ZSTD_isError(ret))
+                               return ret;
+                       if (ret > 0)
+                               return ERROR(srcSize_wrong);
+               }
+
+               ip += headerSize;
+               remainingSize -= headerSize;
+
+               /* Loop on each block */
+               while (1) {
+                       blockProperties_t blockProperties;
+                       size_t const cBlockSize = ZSTD_getcBlockSize(ip, 
remainingSize, &blockProperties);
+                       if (ZSTD_isError(cBlockSize))
+                               return cBlockSize;
+
+                       if (ZSTD_blockHeaderSize + cBlockSize > remainingSize)
+                               return ERROR(srcSize_wrong);
+
+                       ip += ZSTD_blockHeaderSize + cBlockSize;
+                       remainingSize -= ZSTD_blockHeaderSize + cBlockSize;
+
+                       if (blockProperties.lastBlock)
+                               break;
+               }
+
+               if (fParams.checksumFlag) { /* Frame content checksum */
+                       if (remainingSize < 4)
+                               return ERROR(srcSize_wrong);
+                       ip += 4;
+                       remainingSize -= 4;
+               }
+
+               return ip - ipstart;
+       }
+}
+
+/*! ZSTD_decompressFrame() :
+*   @dctx must be properly initialized */
+static size_t ZSTD_decompressFrame(ZSTD_DCtx *dctx, void *dst, size_t 
dstCapacity, const void **srcPtr, size_t *srcSizePtr)
+{
+       const BYTE *ip = (const BYTE *)(*srcPtr);
+       BYTE *const ostart = (BYTE * const)dst;
+       BYTE *const oend = ostart + dstCapacity;
+       BYTE *op = ostart;
+       size_t remainingSize = *srcSizePtr;
+
+       /* check */
+       if (remainingSize < ZSTD_frameHeaderSize_min + ZSTD_blockHeaderSize)
+               return ERROR(srcSize_wrong);
+
+       /* Frame Header */
+       {
+               size_t const frameHeaderSize = ZSTD_frameHeaderSize(ip, 
ZSTD_frameHeaderSize_prefix);
+               if (ZSTD_isError(frameHeaderSize))
+                       return frameHeaderSize;
+               if (remainingSize < frameHeaderSize + ZSTD_blockHeaderSize)
+                       return ERROR(srcSize_wrong);
+               CHECK_F(ZSTD_decodeFrameHeader(dctx, ip, frameHeaderSize));
+               ip += frameHeaderSize;
+               remainingSize -= frameHeaderSize;
+       }
+
+       /* Loop on each block */
+       while (1) {
+               size_t decodedSize;
+               blockProperties_t blockProperties;
+               size_t const cBlockSize = ZSTD_getcBlockSize(ip, remainingSize, 
&blockProperties);
+               if (ZSTD_isError(cBlockSize))
+                       return cBlockSize;
+
+               ip += ZSTD_blockHeaderSize;
+               remainingSize -= ZSTD_blockHeaderSize;
+               if (cBlockSize > remainingSize)
+                       return ERROR(srcSize_wrong);
+
+               switch (blockProperties.blockType) {
+               case bt_compressed: decodedSize = 
ZSTD_decompressBlock_internal(dctx, op, oend - op, ip, cBlockSize); break;
+               case bt_raw: decodedSize = ZSTD_copyRawBlock(op, oend - op, ip, 
cBlockSize); break;
+               case bt_rle: decodedSize = ZSTD_generateNxBytes(op, oend - op, 
*ip, blockProperties.origSize); break;
+               case bt_reserved:
+               default: return ERROR(corruption_detected);
+               }
+
+               if (ZSTD_isError(decodedSize))
+                       return decodedSize;
+               if (dctx->fParams.checksumFlag)
+                       xxh64_update(&dctx->xxhState, op, decodedSize);
+               op += decodedSize;
+               ip += cBlockSize;
+               remainingSize -= cBlockSize;
+               if (blockProperties.lastBlock)
+                       break;
+       }
+
+       if (dctx->fParams.checksumFlag) { /* Frame content checksum 
verification */
+               U32 const checkCalc = (U32)xxh64_digest(&dctx->xxhState);
+               U32 checkRead;
+               if (remainingSize < 4)
+                       return ERROR(checksum_wrong);
+               checkRead = ZSTD_readLE32(ip);
+               if (checkRead != checkCalc)
+                       return ERROR(checksum_wrong);
+               ip += 4;
+               remainingSize -= 4;
+       }
+
+       /* Allow caller to get size read */
+       *srcPtr = ip;
+       *srcSizePtr = remainingSize;
+       return op - ostart;
+}
+
+static const void *ZSTD_DDictDictContent(const ZSTD_DDict *ddict);
+static size_t ZSTD_DDictDictSize(const ZSTD_DDict *ddict);
+
+static size_t ZSTD_decompressMultiFrame(ZSTD_DCtx *dctx, void *dst, size_t 
dstCapacity, const void *src, size_t srcSize, const void *dict, size_t dictSize,
+                                       const ZSTD_DDict *ddict)
+{
+       void *const dststart = dst;
+
+       if (ddict) {
+               if (dict) {
+                       /* programmer error, these two cases should be mutually 
exclusive */
+                       return ERROR(GENERIC);
+               }
+
+               dict = ZSTD_DDictDictContent(ddict);
+               dictSize = ZSTD_DDictDictSize(ddict);
+       }
+
+       while (srcSize >= ZSTD_frameHeaderSize_prefix) {
+               U32 magicNumber;
+
+               magicNumber = ZSTD_readLE32(src);
+               if (magicNumber != ZSTD_MAGICNUMBER) {
+                       if ((magicNumber & 0xFFFFFFF0U) == 
ZSTD_MAGIC_SKIPPABLE_START) {
+                               size_t skippableSize;
+                               if (srcSize < ZSTD_skippableHeaderSize)
+                                       return ERROR(srcSize_wrong);
+                               skippableSize = ZSTD_readLE32((const BYTE *)src 
+ 4) + ZSTD_skippableHeaderSize;
+                               if (srcSize < skippableSize) {
+                                       return ERROR(srcSize_wrong);
+                               }
+
+                               src = (const BYTE *)src + skippableSize;
+                               srcSize -= skippableSize;
+                               continue;
+                       } else {
+                               return ERROR(prefix_unknown);
+                       }
+               }
+
+               if (ddict) {
+                       /* we were called from ZSTD_decompress_usingDDict */
+                       ZSTD_refDDict(dctx, ddict);
+               } else {
+                       /* this will initialize correctly with no dict if dict 
== NULL, so
+                        * use this in all cases but ddict */
+                       CHECK_F(ZSTD_decompressBegin_usingDict(dctx, dict, 
dictSize));
+               }
+               ZSTD_checkContinuity(dctx, dst);
+
+               {
+                       const size_t res = ZSTD_decompressFrame(dctx, dst, 
dstCapacity, &src, &srcSize);
+                       if (ZSTD_isError(res))
+                               return res;
+                       /* don't need to bounds check this, 
ZSTD_decompressFrame will have
+                        * already */
+                       dst = (BYTE *)dst + res;
+                       dstCapacity -= res;
+               }
+       }
+
+       if (srcSize)
+               return ERROR(srcSize_wrong); /* input not entirely consumed */
+
+       return (BYTE *)dst - (BYTE *)dststart;
+}
+
+size_t ZSTD_decompress_usingDict(ZSTD_DCtx *dctx, void *dst, size_t 
dstCapacity, const void *src, size_t srcSize, const void *dict, size_t dictSize)
+{
+       return ZSTD_decompressMultiFrame(dctx, dst, dstCapacity, src, srcSize, 
dict, dictSize, NULL);
+}
+
+size_t ZSTD_decompressDCtx(ZSTD_DCtx *dctx, void *dst, size_t dstCapacity, 
const void *src, size_t srcSize)
+{
+       return ZSTD_decompress_usingDict(dctx, dst, dstCapacity, src, srcSize, 
NULL, 0);
+}
+
+/*-**************************************
+*   Advanced Streaming Decompression API
+*   Bufferless and synchronous
+****************************************/
+size_t ZSTD_nextSrcSizeToDecompress(ZSTD_DCtx *dctx) { return dctx->expected; }
+
+ZSTD_nextInputType_e ZSTD_nextInputType(ZSTD_DCtx *dctx)
+{
+       switch (dctx->stage) {
+       default: /* should not happen */
+       case ZSTDds_getFrameHeaderSize:
+       case ZSTDds_decodeFrameHeader: return ZSTDnit_frameHeader;
+       case ZSTDds_decodeBlockHeader: return ZSTDnit_blockHeader;
+       case ZSTDds_decompressBlock: return ZSTDnit_block;
+       case ZSTDds_decompressLastBlock: return ZSTDnit_lastBlock;
+       case ZSTDds_checkChecksum: return ZSTDnit_checksum;
+       case ZSTDds_decodeSkippableHeader:
+       case ZSTDds_skipFrame: return ZSTDnit_skippableFrame;
+       }
+}
+
+int ZSTD_isSkipFrame(ZSTD_DCtx *dctx) { return dctx->stage == 
ZSTDds_skipFrame; } /* for zbuff */
+
+/** ZSTD_decompressContinue() :
+*   @return : nb of bytes generated into `dst` (necessarily <= `dstCapacity)
+*             or an error code, which can be tested using ZSTD_isError() */
+size_t ZSTD_decompressContinue(ZSTD_DCtx *dctx, void *dst, size_t dstCapacity, 
const void *src, size_t srcSize)
+{
+       /* Sanity check */
+       if (srcSize != dctx->expected)
+               return ERROR(srcSize_wrong);
+       if (dstCapacity)
+               ZSTD_checkContinuity(dctx, dst);
+
+       switch (dctx->stage) {
+       case ZSTDds_getFrameHeaderSize:
+               if (srcSize != ZSTD_frameHeaderSize_prefix)
+                       return ERROR(srcSize_wrong);                            
        /* impossible */
+               if ((ZSTD_readLE32(src) & 0xFFFFFFF0U) == 
ZSTD_MAGIC_SKIPPABLE_START) { /* skippable frame */
+                       memcpy(dctx->headerBuffer, src, 
ZSTD_frameHeaderSize_prefix);
+                       dctx->expected = ZSTD_skippableHeaderSize - 
ZSTD_frameHeaderSize_prefix; /* magic number + skippable frame length */
+                       dctx->stage = ZSTDds_decodeSkippableHeader;
+                       return 0;
+               }
+               dctx->headerSize = ZSTD_frameHeaderSize(src, 
ZSTD_frameHeaderSize_prefix);
+               if (ZSTD_isError(dctx->headerSize))
+                       return dctx->headerSize;
+               memcpy(dctx->headerBuffer, src, ZSTD_frameHeaderSize_prefix);
+               if (dctx->headerSize > ZSTD_frameHeaderSize_prefix) {
+                       dctx->expected = dctx->headerSize - 
ZSTD_frameHeaderSize_prefix;
+                       dctx->stage = ZSTDds_decodeFrameHeader;
+                       return 0;
+               }
+               dctx->expected = 0; /* not necessary to copy more */
+
+       case ZSTDds_decodeFrameHeader:
+               memcpy(dctx->headerBuffer + ZSTD_frameHeaderSize_prefix, src, 
dctx->expected);
+               CHECK_F(ZSTD_decodeFrameHeader(dctx, dctx->headerBuffer, 
dctx->headerSize));
+               dctx->expected = ZSTD_blockHeaderSize;
+               dctx->stage = ZSTDds_decodeBlockHeader;
+               return 0;
+
+       case ZSTDds_decodeBlockHeader: {
+               blockProperties_t bp;
+               size_t const cBlockSize = ZSTD_getcBlockSize(src, 
ZSTD_blockHeaderSize, &bp);
+               if (ZSTD_isError(cBlockSize))
+                       return cBlockSize;
+               dctx->expected = cBlockSize;
+               dctx->bType = bp.blockType;
+               dctx->rleSize = bp.origSize;
+               if (cBlockSize) {
+                       dctx->stage = bp.lastBlock ? ZSTDds_decompressLastBlock 
: ZSTDds_decompressBlock;
+                       return 0;
+               }
+               /* empty block */
+               if (bp.lastBlock) {
+                       if (dctx->fParams.checksumFlag) {
+                               dctx->expected = 4;
+                               dctx->stage = ZSTDds_checkChecksum;
+                       } else {
+                               dctx->expected = 0; /* end of frame */
+                               dctx->stage = ZSTDds_getFrameHeaderSize;
+                       }
+               } else {
+                       dctx->expected = 3; /* go directly to next header */
+                       dctx->stage = ZSTDds_decodeBlockHeader;
+               }
+               return 0;
+       }
+       case ZSTDds_decompressLastBlock:
+       case ZSTDds_decompressBlock: {
+               size_t rSize;
+               switch (dctx->bType) {
+               case bt_compressed: rSize = ZSTD_decompressBlock_internal(dctx, 
dst, dstCapacity, src, srcSize); break;
+               case bt_raw: rSize = ZSTD_copyRawBlock(dst, dstCapacity, src, 
srcSize); break;
+               case bt_rle: rSize = ZSTD_setRleBlock(dst, dstCapacity, src, 
srcSize, dctx->rleSize); break;
+               case bt_reserved: /* should never happen */
+               default: return ERROR(corruption_detected);
+               }
+               if (ZSTD_isError(rSize))
+                       return rSize;
+               if (dctx->fParams.checksumFlag)
+                       xxh64_update(&dctx->xxhState, dst, rSize);
+
+               if (dctx->stage == ZSTDds_decompressLastBlock) { /* end of 
frame */
+                       if (dctx->fParams.checksumFlag) {       /* another 
round for frame checksum */
+                               dctx->expected = 4;
+                               dctx->stage = ZSTDds_checkChecksum;
+                       } else {
+                               dctx->expected = 0; /* ends here */
+                               dctx->stage = ZSTDds_getFrameHeaderSize;
+                       }
+               } else {
+                       dctx->stage = ZSTDds_decodeBlockHeader;
+                       dctx->expected = ZSTD_blockHeaderSize;
+                       dctx->previousDstEnd = (char *)dst + rSize;
+               }
+               return rSize;
+       }
+       case ZSTDds_checkChecksum: {
+               U32 const h32 = (U32)xxh64_digest(&dctx->xxhState);
+               U32 const check32 = ZSTD_readLE32(src); /* srcSize == 4, 
guaranteed by dctx->expected */
+               if (check32 != h32)
+                       return ERROR(checksum_wrong);
+               dctx->expected = 0;
+               dctx->stage = ZSTDds_getFrameHeaderSize;
+               return 0;
+       }
+       case ZSTDds_decodeSkippableHeader: {
+               memcpy(dctx->headerBuffer + ZSTD_frameHeaderSize_prefix, src, 
dctx->expected);
+               dctx->expected = ZSTD_readLE32(dctx->headerBuffer + 4);
+               dctx->stage = ZSTDds_skipFrame;
+               return 0;
+       }
+       case ZSTDds_skipFrame: {
+               dctx->expected = 0;
+               dctx->stage = ZSTDds_getFrameHeaderSize;
+               return 0;
+       }
+       default:
+               return ERROR(GENERIC); /* impossible */
+       }
+}
+
+static size_t ZSTD_refDictContent(ZSTD_DCtx *dctx, const void *dict, size_t 
dictSize)
+{
+       dctx->dictEnd = dctx->previousDstEnd;
+       dctx->vBase = (const char *)dict - ((const char 
*)(dctx->previousDstEnd) - (const char *)(dctx->base));
+       dctx->base = dict;
+       dctx->previousDstEnd = (const char *)dict + dictSize;
+       return 0;
+}
+
+/* ZSTD_loadEntropy() :
+ * dict : must point at beginning of a valid zstd dictionary
+ * @return : size of entropy tables read */
+static size_t ZSTD_loadEntropy(ZSTD_entropyTables_t *entropy, const void 
*const dict, size_t const dictSize)
+{
+       const BYTE *dictPtr = (const BYTE *)dict;
+       const BYTE *const dictEnd = dictPtr + dictSize;
+
+       if (dictSize <= 8)
+               return ERROR(dictionary_corrupted);
+       dictPtr += 8; /* skip header = magic + dictID */
+
+       {
+               size_t const hSize = HUF_readDTableX4_wksp(entropy->hufTable, 
dictPtr, dictEnd - dictPtr, entropy->workspace, sizeof(entropy->workspace));
+               if (HUF_isError(hSize))
+                       return ERROR(dictionary_corrupted);
+               dictPtr += hSize;
+       }
+
+       {
+               short offcodeNCount[MaxOff + 1];
+               U32 offcodeMaxValue = MaxOff, offcodeLog;
+               size_t const offcodeHeaderSize = FSE_readNCount(offcodeNCount, 
&offcodeMaxValue, &offcodeLog, dictPtr, dictEnd - dictPtr);
+               if (FSE_isError(offcodeHeaderSize))
+                       return ERROR(dictionary_corrupted);
+               if (offcodeLog > OffFSELog)
+                       return ERROR(dictionary_corrupted);
+               CHECK_E(FSE_buildDTable_wksp(entropy->OFTable, offcodeNCount, 
offcodeMaxValue, offcodeLog, entropy->workspace, sizeof(entropy->workspace)), 
dictionary_corrupted);
+               dictPtr += offcodeHeaderSize;
+       }
+
+       {
+               short matchlengthNCount[MaxML + 1];
+               unsigned matchlengthMaxValue = MaxML, matchlengthLog;
+               size_t const matchlengthHeaderSize = 
FSE_readNCount(matchlengthNCount, &matchlengthMaxValue, &matchlengthLog, 
dictPtr, dictEnd - dictPtr);
+               if (FSE_isError(matchlengthHeaderSize))
+                       return ERROR(dictionary_corrupted);
+               if (matchlengthLog > MLFSELog)
+                       return ERROR(dictionary_corrupted);
+               CHECK_E(FSE_buildDTable_wksp(entropy->MLTable, 
matchlengthNCount, matchlengthMaxValue, matchlengthLog, entropy->workspace, 
sizeof(entropy->workspace)), dictionary_corrupted);
+               dictPtr += matchlengthHeaderSize;
+       }
+
+       {
+               short litlengthNCount[MaxLL + 1];
+               unsigned litlengthMaxValue = MaxLL, litlengthLog;
+               size_t const litlengthHeaderSize = 
FSE_readNCount(litlengthNCount, &litlengthMaxValue, &litlengthLog, dictPtr, 
dictEnd - dictPtr);
+               if (FSE_isError(litlengthHeaderSize))
+                       return ERROR(dictionary_corrupted);
+               if (litlengthLog > LLFSELog)
+                       return ERROR(dictionary_corrupted);
+               CHECK_E(FSE_buildDTable_wksp(entropy->LLTable, litlengthNCount, 
litlengthMaxValue, litlengthLog, entropy->workspace, 
sizeof(entropy->workspace)), dictionary_corrupted);
+               dictPtr += litlengthHeaderSize;
+       }
+
+       if (dictPtr + 12 > dictEnd)
+               return ERROR(dictionary_corrupted);
+       {
+               int i;
+               size_t const dictContentSize = (size_t)(dictEnd - (dictPtr + 
12));
+               for (i = 0; i < 3; i++) {
+                       U32 const rep = ZSTD_readLE32(dictPtr);
+                       dictPtr += 4;
+                       if (rep == 0 || rep >= dictContentSize)
+                               return ERROR(dictionary_corrupted);
+                       entropy->rep[i] = rep;
+               }
+       }
+
+       return dictPtr - (const BYTE *)dict;
+}
+
+static size_t ZSTD_decompress_insertDictionary(ZSTD_DCtx *dctx, const void 
*dict, size_t dictSize)
+{
+       if (dictSize < 8)
+               return ZSTD_refDictContent(dctx, dict, dictSize);
+       {
+               U32 const magic = ZSTD_readLE32(dict);
+               if (magic != ZSTD_DICT_MAGIC) {
+                       return ZSTD_refDictContent(dctx, dict, dictSize); /* 
pure content mode */
+               }
+       }
+       dctx->dictID = ZSTD_readLE32((const char *)dict + 4);
+
+       /* load entropy tables */
+       {
+               size_t const eSize = ZSTD_loadEntropy(&dctx->entropy, dict, 
dictSize);
+               if (ZSTD_isError(eSize))
+                       return ERROR(dictionary_corrupted);
+               dict = (const char *)dict + eSize;
+               dictSize -= eSize;
+       }
+       dctx->litEntropy = dctx->fseEntropy = 1;
+
+       /* reference dictionary content */
+       return ZSTD_refDictContent(dctx, dict, dictSize);
+}
+
+size_t ZSTD_decompressBegin_usingDict(ZSTD_DCtx *dctx, const void *dict, 
size_t dictSize)
+{
+       CHECK_F(ZSTD_decompressBegin(dctx));
+       if (dict && dictSize)
+               CHECK_E(ZSTD_decompress_insertDictionary(dctx, dict, dictSize), 
dictionary_corrupted);
+       return 0;
+}
+
+/* ======   ZSTD_DDict   ====== */
+
+struct ZSTD_DDict_s {
+       void *dictBuffer;
+       const void *dictContent;
+       size_t dictSize;
+       ZSTD_entropyTables_t entropy;
+       U32 dictID;
+       U32 entropyPresent;
+       ZSTD_customMem cMem;
+}; /* typedef'd to ZSTD_DDict within "zstd.h" */
+
+size_t ZSTD_DDictWorkspaceBound(void) { return ZSTD_ALIGN(sizeof(ZSTD_stack)) 
+ ZSTD_ALIGN(sizeof(ZSTD_DDict)); }
+
+static const void *ZSTD_DDictDictContent(const ZSTD_DDict *ddict) { return 
ddict->dictContent; }
+
+static size_t ZSTD_DDictDictSize(const ZSTD_DDict *ddict) { return 
ddict->dictSize; }
+
+static void ZSTD_refDDict(ZSTD_DCtx *dstDCtx, const ZSTD_DDict *ddict)
+{
+       ZSTD_decompressBegin(dstDCtx); /* init */
+       if (ddict) {                   /* support refDDict on NULL */
+               dstDCtx->dictID = ddict->dictID;
+               dstDCtx->base = ddict->dictContent;
+               dstDCtx->vBase = ddict->dictContent;
+               dstDCtx->dictEnd = (const BYTE *)ddict->dictContent + 
ddict->dictSize;
+               dstDCtx->previousDstEnd = dstDCtx->dictEnd;
+               if (ddict->entropyPresent) {
+                       dstDCtx->litEntropy = 1;
+                       dstDCtx->fseEntropy = 1;
+                       dstDCtx->LLTptr = ddict->entropy.LLTable;
+                       dstDCtx->MLTptr = ddict->entropy.MLTable;
+                       dstDCtx->OFTptr = ddict->entropy.OFTable;
+                       dstDCtx->HUFptr = ddict->entropy.hufTable;
+                       dstDCtx->entropy.rep[0] = ddict->entropy.rep[0];
+                       dstDCtx->entropy.rep[1] = ddict->entropy.rep[1];
+                       dstDCtx->entropy.rep[2] = ddict->entropy.rep[2];
+               } else {
+                       dstDCtx->litEntropy = 0;
+                       dstDCtx->fseEntropy = 0;
+               }
+       }
+}
+
+static size_t ZSTD_loadEntropy_inDDict(ZSTD_DDict *ddict)
+{
+       ddict->dictID = 0;
+       ddict->entropyPresent = 0;
+       if (ddict->dictSize < 8)
+               return 0;
+       {
+               U32 const magic = ZSTD_readLE32(ddict->dictContent);
+               if (magic != ZSTD_DICT_MAGIC)
+                       return 0; /* pure content mode */
+       }
+       ddict->dictID = ZSTD_readLE32((const char *)ddict->dictContent + 4);
+
+       /* load entropy tables */
+       CHECK_E(ZSTD_loadEntropy(&ddict->entropy, ddict->dictContent, 
ddict->dictSize), dictionary_corrupted);
+       ddict->entropyPresent = 1;
+       return 0;
+}
+
+static ZSTD_DDict *ZSTD_createDDict_advanced(const void *dict, size_t 
dictSize, unsigned byReference, ZSTD_customMem customMem)
+{
+       if (!customMem.customAlloc || !customMem.customFree)
+               return NULL;
+
+       {
+               ZSTD_DDict *const ddict = (ZSTD_DDict 
*)ZSTD_malloc(sizeof(ZSTD_DDict), customMem);
+               if (!ddict)
+                       return NULL;
+               ddict->cMem = customMem;
+
+               if ((byReference) || (!dict) || (!dictSize)) {
+                       ddict->dictBuffer = NULL;
+                       ddict->dictContent = dict;
+               } else {
+                       void *const internalBuffer = ZSTD_malloc(dictSize, 
customMem);
+                       if (!internalBuffer) {
+                               ZSTD_freeDDict(ddict);
+                               return NULL;
+                       }
+                       memcpy(internalBuffer, dict, dictSize);
+                       ddict->dictBuffer = internalBuffer;
+                       ddict->dictContent = internalBuffer;
+               }
+               ddict->dictSize = dictSize;
+               ddict->entropy.hufTable[0] = (HUF_DTable)((HufLog)*0x1000001); 
/* cover both little and big endian */
+               /* parse dictionary content */
+               {
+                       size_t const errorCode = 
ZSTD_loadEntropy_inDDict(ddict);
+                       if (ZSTD_isError(errorCode)) {
+                               ZSTD_freeDDict(ddict);
+                               return NULL;
+                       }
+               }
+
+               return ddict;
+       }
+}
+
+/*! ZSTD_initDDict() :
+*   Create a digested dictionary, to start decompression without startup delay.
+*   `dict` content is copied inside DDict.
+*   Consequently, `dict` can be released after `ZSTD_DDict` creation */
+ZSTD_DDict *ZSTD_initDDict(const void *dict, size_t dictSize, void *workspace, 
size_t workspaceSize)
+{
+       ZSTD_customMem const stackMem = ZSTD_initStack(workspace, 
workspaceSize);
+       return ZSTD_createDDict_advanced(dict, dictSize, 1, stackMem);
+}
+
+size_t ZSTD_freeDDict(ZSTD_DDict *ddict)
+{
+       if (ddict == NULL)
+               return 0; /* support free on NULL */
+       {
+               ZSTD_customMem const cMem = ddict->cMem;
+               ZSTD_free(ddict->dictBuffer, cMem);
+               ZSTD_free(ddict, cMem);
+               return 0;
+       }
+}
+
+/*! ZSTD_getDictID_fromDict() :
+ *  Provides the dictID stored within dictionary.
+ *  if @return == 0, the dictionary is not conformant with Zstandard 
specification.
+ *  It can still be loaded, but as a content-only dictionary. */
+unsigned ZSTD_getDictID_fromDict(const void *dict, size_t dictSize)
+{
+       if (dictSize < 8)
+               return 0;
+       if (ZSTD_readLE32(dict) != ZSTD_DICT_MAGIC)
+               return 0;
+       return ZSTD_readLE32((const char *)dict + 4);
+}
+
+/*! ZSTD_getDictID_fromDDict() :
+ *  Provides the dictID of the dictionary loaded into `ddict`.
+ *  If @return == 0, the dictionary is not conformant to Zstandard 
specification, or empty.
+ *  Non-conformant dictionaries can still be loaded, but as content-only 
dictionaries. */
+unsigned ZSTD_getDictID_fromDDict(const ZSTD_DDict *ddict)
+{
+       if (ddict == NULL)
+               return 0;
+       return ZSTD_getDictID_fromDict(ddict->dictContent, ddict->dictSize);
+}
+
+/*! ZSTD_getDictID_fromFrame() :
+ *  Provides the dictID required to decompressed the frame stored within `src`.
+ *  If @return == 0, the dictID could not be decoded.
+ *  This could for one of the following reasons :
+ *  - The frame does not require a dictionary to be decoded (most common case).
+ *  - The frame was built with dictID intentionally removed. Whatever 
dictionary is necessary is a hidden information.
+ *    Note : this use case also happens when using a non-conformant dictionary.
+ *  - `srcSize` is too small, and as a result, the frame header could not be 
decoded (only possible if `srcSize < ZSTD_FRAMEHEADERSIZE_MAX`).
+ *  - This is not a Zstandard frame.
+ *  When identifying the exact failure cause, it's possible to used 
ZSTD_getFrameParams(), which will provide a more precise error code. */
+unsigned ZSTD_getDictID_fromFrame(const void *src, size_t srcSize)
+{
+       ZSTD_frameParams zfp = {0, 0, 0, 0};
+       size_t const hError = ZSTD_getFrameParams(&zfp, src, srcSize);
+       if (ZSTD_isError(hError))
+               return 0;
+       return zfp.dictID;
+}
+
+/*! ZSTD_decompress_usingDDict() :
+*   Decompression using a pre-digested Dictionary
+*   Use dictionary without significant overhead. */
+size_t ZSTD_decompress_usingDDict(ZSTD_DCtx *dctx, void *dst, size_t 
dstCapacity, const void *src, size_t srcSize, const ZSTD_DDict *ddict)
+{
+       /* pass content and size in case legacy frames are encountered */
+       return ZSTD_decompressMultiFrame(dctx, dst, dstCapacity, src, srcSize, 
NULL, 0, ddict);
+}
+
+/*=====================================
+*   Streaming decompression
+*====================================*/
+
+typedef enum { zdss_init, zdss_loadHeader, zdss_read, zdss_load, zdss_flush } 
ZSTD_dStreamStage;
+
+/* *** Resource management *** */
+struct ZSTD_DStream_s {
+       ZSTD_DCtx *dctx;
+       ZSTD_DDict *ddictLocal;
+       const ZSTD_DDict *ddict;
+       ZSTD_frameParams fParams;
+       ZSTD_dStreamStage stage;
+       char *inBuff;
+       size_t inBuffSize;
+       size_t inPos;
+       size_t maxWindowSize;
+       char *outBuff;
+       size_t outBuffSize;
+       size_t outStart;
+       size_t outEnd;
+       size_t blockSize;
+       BYTE headerBuffer[ZSTD_FRAMEHEADERSIZE_MAX]; /* tmp buffer to store 
frame header */
+       size_t lhSize;
+       ZSTD_customMem customMem;
+       void *legacyContext;
+       U32 previousLegacyVersion;
+       U32 legacyVersion;
+       U32 hostageByte;
+}; /* typedef'd to ZSTD_DStream within "zstd.h" */
+
+size_t ZSTD_DStreamWorkspaceBound(size_t maxWindowSize)
+{
+       size_t const blockSize = MIN(maxWindowSize, ZSTD_BLOCKSIZE_ABSOLUTEMAX);
+       size_t const inBuffSize = blockSize;
+       size_t const outBuffSize = maxWindowSize + blockSize + 
WILDCOPY_OVERLENGTH * 2;
+       return ZSTD_DCtxWorkspaceBound() + ZSTD_ALIGN(sizeof(ZSTD_DStream)) + 
ZSTD_ALIGN(inBuffSize) + ZSTD_ALIGN(outBuffSize);
+}
+
+static ZSTD_DStream *ZSTD_createDStream_advanced(ZSTD_customMem customMem)
+{
+       ZSTD_DStream *zds;
+
+       if (!customMem.customAlloc || !customMem.customFree)
+               return NULL;
+
+       zds = (ZSTD_DStream *)ZSTD_malloc(sizeof(ZSTD_DStream), customMem);
+       if (zds == NULL)
+               return NULL;
+       memset(zds, 0, sizeof(ZSTD_DStream));
+       memcpy(&zds->customMem, &customMem, sizeof(ZSTD_customMem));
+       zds->dctx = ZSTD_createDCtx_advanced(customMem);
+       if (zds->dctx == NULL) {
+               ZSTD_freeDStream(zds);
+               return NULL;
+       }
+       zds->stage = zdss_init;
+       zds->maxWindowSize = ZSTD_MAXWINDOWSIZE_DEFAULT;
+       return zds;
+}
+
+ZSTD_DStream *ZSTD_initDStream(size_t maxWindowSize, void *workspace, size_t 
workspaceSize)
+{
+       ZSTD_customMem const stackMem = ZSTD_initStack(workspace, 
workspaceSize);
+       ZSTD_DStream *zds = ZSTD_createDStream_advanced(stackMem);
+       if (!zds) {
+               return NULL;
+       }
+
+       zds->maxWindowSize = maxWindowSize;
+       zds->stage = zdss_loadHeader;
+       zds->lhSize = zds->inPos = zds->outStart = zds->outEnd = 0;
+       ZSTD_freeDDict(zds->ddictLocal);
+       zds->ddictLocal = NULL;
+       zds->ddict = zds->ddictLocal;
+       zds->legacyVersion = 0;
+       zds->hostageByte = 0;
+
+       {
+               size_t const blockSize = MIN(zds->maxWindowSize, 
ZSTD_BLOCKSIZE_ABSOLUTEMAX);
+               size_t const neededOutSize = zds->maxWindowSize + blockSize + 
WILDCOPY_OVERLENGTH * 2;
+
+               zds->inBuff = (char *)ZSTD_malloc(blockSize, zds->customMem);
+               zds->inBuffSize = blockSize;
+               zds->outBuff = (char *)ZSTD_malloc(neededOutSize, 
zds->customMem);
+               zds->outBuffSize = neededOutSize;
+               if (zds->inBuff == NULL || zds->outBuff == NULL) {
+                       ZSTD_freeDStream(zds);
+                       return NULL;
+               }
+       }
+       return zds;
+}
+
+ZSTD_DStream *ZSTD_initDStream_usingDDict(size_t maxWindowSize, const 
ZSTD_DDict *ddict, void *workspace, size_t workspaceSize)
+{
+       ZSTD_DStream *zds = ZSTD_initDStream(maxWindowSize, workspace, 
workspaceSize);
+       if (zds) {
+               zds->ddict = ddict;
+       }
+       return zds;
+}
+
+size_t ZSTD_freeDStream(ZSTD_DStream *zds)
+{
+       if (zds == NULL)
+               return 0; /* support free on null */
+       {
+               ZSTD_customMem const cMem = zds->customMem;
+               ZSTD_freeDCtx(zds->dctx);
+               zds->dctx = NULL;
+               ZSTD_freeDDict(zds->ddictLocal);
+               zds->ddictLocal = NULL;
+               ZSTD_free(zds->inBuff, cMem);
+               zds->inBuff = NULL;
+               ZSTD_free(zds->outBuff, cMem);
+               zds->outBuff = NULL;
+               ZSTD_free(zds, cMem);
+               return 0;
+       }
+}
+
+/* *** Initialization *** */
+
+size_t ZSTD_DStreamInSize(void) { return ZSTD_BLOCKSIZE_ABSOLUTEMAX + 
ZSTD_blockHeaderSize; }
+size_t ZSTD_DStreamOutSize(void) { return ZSTD_BLOCKSIZE_ABSOLUTEMAX; }
+
+size_t ZSTD_resetDStream(ZSTD_DStream *zds)
+{
+       zds->stage = zdss_loadHeader;
+       zds->lhSize = zds->inPos = zds->outStart = zds->outEnd = 0;
+       zds->legacyVersion = 0;
+       zds->hostageByte = 0;
+       return ZSTD_frameHeaderSize_prefix;
+}
+
+/* *****   Decompression   ***** */
+
+ZSTD_STATIC size_t ZSTD_limitCopy(void *dst, size_t dstCapacity, const void 
*src, size_t srcSize)
+{
+       size_t const length = MIN(dstCapacity, srcSize);
+       memcpy(dst, src, length);
+       return length;
+}
+
+size_t ZSTD_decompressStream(ZSTD_DStream *zds, ZSTD_outBuffer *output, 
ZSTD_inBuffer *input)
+{
+       const char *const istart = (const char *)(input->src) + input->pos;
+       const char *const iend = (const char *)(input->src) + input->size;
+       const char *ip = istart;
+       char *const ostart = (char *)(output->dst) + output->pos;
+       char *const oend = (char *)(output->dst) + output->size;
+       char *op = ostart;
+       U32 someMoreWork = 1;
+
+       while (someMoreWork) {
+               switch (zds->stage) {
+               case zdss_init:
+                       ZSTD_resetDStream(zds); /* transparent reset on 
starting decoding a new frame */
+                                               /* fall-through */
+
+               case zdss_loadHeader: {
+                       size_t const hSize = ZSTD_getFrameParams(&zds->fParams, 
zds->headerBuffer, zds->lhSize);
+                       if (ZSTD_isError(hSize))
+                               return hSize;
+                       if (hSize != 0) {                                  /* 
need more input */
+                               size_t const toLoad = hSize - zds->lhSize; /* 
if hSize!=0, hSize > zds->lhSize */
+                               if (toLoad > (size_t)(iend - ip)) {     /* not 
enough input to load full header */
+                                       memcpy(zds->headerBuffer + zds->lhSize, 
ip, iend - ip);
+                                       zds->lhSize += iend - ip;
+                                       input->pos = input->size;
+                                       return (MAX(ZSTD_frameHeaderSize_min, 
hSize) - zds->lhSize) +
+                                              ZSTD_blockHeaderSize; /* 
remaining header bytes + next block header */
+                               }
+                               memcpy(zds->headerBuffer + zds->lhSize, ip, 
toLoad);
+                               zds->lhSize = hSize;
+                               ip += toLoad;
+                               break;
+                       }
+
+                       /* check for single-pass mode opportunity */
+                       if (zds->fParams.frameContentSize && 
zds->fParams.windowSize /* skippable frame if == 0 */
+                           && (U64)(size_t)(oend - op) >= 
zds->fParams.frameContentSize) {
+                               size_t const cSize = 
ZSTD_findFrameCompressedSize(istart, iend - istart);
+                               if (cSize <= (size_t)(iend - istart)) {
+                                       size_t const decompressedSize = 
ZSTD_decompress_usingDDict(zds->dctx, op, oend - op, istart, cSize, zds->ddict);
+                                       if (ZSTD_isError(decompressedSize))
+                                               return decompressedSize;
+                                       ip = istart + cSize;
+                                       op += decompressedSize;
+                                       zds->dctx->expected = 0;
+                                       zds->stage = zdss_init;
+                                       someMoreWork = 0;
+                                       break;
+                               }
+                       }
+
+                       /* Consume header */
+                       ZSTD_refDDict(zds->dctx, zds->ddict);
+                       {
+                               size_t const h1Size = 
ZSTD_nextSrcSizeToDecompress(zds->dctx); /* == ZSTD_frameHeaderSize_prefix */
+                               CHECK_F(ZSTD_decompressContinue(zds->dctx, 
NULL, 0, zds->headerBuffer, h1Size));
+                               {
+                                       size_t const h2Size = 
ZSTD_nextSrcSizeToDecompress(zds->dctx);
+                                       
CHECK_F(ZSTD_decompressContinue(zds->dctx, NULL, 0, zds->headerBuffer + h1Size, 
h2Size));
+                               }
+                       }
+
+                       zds->fParams.windowSize = MAX(zds->fParams.windowSize, 
1U << ZSTD_WINDOWLOG_ABSOLUTEMIN);
+                       if (zds->fParams.windowSize > zds->maxWindowSize)
+                               return ERROR(frameParameter_windowTooLarge);
+
+                       /* Buffers are preallocated, but double check */
+                       {
+                               size_t const blockSize = 
MIN(zds->maxWindowSize, ZSTD_BLOCKSIZE_ABSOLUTEMAX);
+                               size_t const neededOutSize = zds->maxWindowSize 
+ blockSize + WILDCOPY_OVERLENGTH * 2;
+                               if (zds->inBuffSize < blockSize) {
+                                       return ERROR(GENERIC);
+                               }
+                               if (zds->outBuffSize < neededOutSize) {
+                                       return ERROR(GENERIC);
+                               }
+                               zds->blockSize = blockSize;
+                       }
+                       zds->stage = zdss_read;
+               }
+               /* pass-through */
+
+               case zdss_read: {
+                       size_t const neededInSize = 
ZSTD_nextSrcSizeToDecompress(zds->dctx);
+                       if (neededInSize == 0) { /* end of frame */
+                               zds->stage = zdss_init;
+                               someMoreWork = 0;
+                               break;
+                       }
+                       if ((size_t)(iend - ip) >= neededInSize) { /* decode 
directly from src */
+                               const int isSkipFrame = 
ZSTD_isSkipFrame(zds->dctx);
+                               size_t const decodedSize = 
ZSTD_decompressContinue(zds->dctx, zds->outBuff + zds->outStart,
+                                                                               
   (isSkipFrame ? 0 : zds->outBuffSize - zds->outStart), ip, neededInSize);
+                               if (ZSTD_isError(decodedSize))
+                                       return decodedSize;
+                               ip += neededInSize;
+                               if (!decodedSize && !isSkipFrame)
+                                       break; /* this was just a header */
+                               zds->outEnd = zds->outStart + decodedSize;
+                               zds->stage = zdss_flush;
+                               break;
+                       }
+                       if (ip == iend) {
+                               someMoreWork = 0;
+                               break;
+                       } /* no more input */
+                       zds->stage = zdss_load;
+                       /* pass-through */
+               }
+
+               case zdss_load: {
+                       size_t const neededInSize = 
ZSTD_nextSrcSizeToDecompress(zds->dctx);
+                       size_t const toLoad = neededInSize - zds->inPos; /* 
should always be <= remaining space within inBuff */
+                       size_t loadedSize;
+                       if (toLoad > zds->inBuffSize - zds->inPos)
+                               return ERROR(corruption_detected); /* should 
never happen */
+                       loadedSize = ZSTD_limitCopy(zds->inBuff + zds->inPos, 
toLoad, ip, iend - ip);
+                       ip += loadedSize;
+                       zds->inPos += loadedSize;
+                       if (loadedSize < toLoad) {
+                               someMoreWork = 0;
+                               break;
+                       } /* not enough input, wait for more */
+
+                       /* decode loaded input */
+                       {
+                               const int isSkipFrame = 
ZSTD_isSkipFrame(zds->dctx);
+                               size_t const decodedSize = 
ZSTD_decompressContinue(zds->dctx, zds->outBuff + zds->outStart, 
zds->outBuffSize - zds->outStart,
+                                                                               
   zds->inBuff, neededInSize);
+                               if (ZSTD_isError(decodedSize))
+                                       return decodedSize;
+                               zds->inPos = 0; /* input is consumed */
+                               if (!decodedSize && !isSkipFrame) {
+                                       zds->stage = zdss_read;
+                                       break;
+                               } /* this was just a header */
+                               zds->outEnd = zds->outStart + decodedSize;
+                               zds->stage = zdss_flush;
+                               /* pass-through */
+                       }
+               }
+
+               case zdss_flush: {
+                       size_t const toFlushSize = zds->outEnd - zds->outStart;
+                       size_t const flushedSize = ZSTD_limitCopy(op, oend - 
op, zds->outBuff + zds->outStart, toFlushSize);
+                       op += flushedSize;
+                       zds->outStart += flushedSize;
+                       if (flushedSize == toFlushSize) { /* flush completed */
+                               zds->stage = zdss_read;
+                               if (zds->outStart + zds->blockSize > 
zds->outBuffSize)
+                                       zds->outStart = zds->outEnd = 0;
+                               break;
+                       }
+                       /* cannot complete flush */
+                       someMoreWork = 0;
+                       break;
+               }
+               default:
+                       return ERROR(GENERIC); /* impossible */
+               }
+       }
+
+       /* result */
+       input->pos += (size_t)(ip - istart);
+       output->pos += (size_t)(op - ostart);
+       {
+               size_t nextSrcSizeHint = 
ZSTD_nextSrcSizeToDecompress(zds->dctx);
+               if (!nextSrcSizeHint) {                     /* frame fully 
decoded */
+                       if (zds->outEnd == zds->outStart) { /* output fully 
flushed */
+                               if (zds->hostageByte) {
+                                       if (input->pos >= input->size) {
+                                               zds->stage = zdss_read;
+                                               return 1;
+                                       }            /* can't release hostage 
(not present) */
+                                       input->pos++; /* release hostage */
+                               }
+                               return 0;
+                       }
+                       if (!zds->hostageByte) { /* output not fully flushed; 
keep last byte as hostage; will be released when all output is flushed */
+                               input->pos--;    /* note : pos > 0, otherwise, 
impossible to finish reading last block */
+                               zds->hostageByte = 1;
+                       }
+                       return 1;
+               }
+               nextSrcSizeHint += ZSTD_blockHeaderSize * 
(ZSTD_nextInputType(zds->dctx) == ZSTDnit_block); /* preload header of next 
block */
+               if (zds->inPos > nextSrcSizeHint)
+                       return ERROR(GENERIC); /* should never happen */
+               nextSrcSizeHint -= zds->inPos; /* already loaded*/
+               return nextSrcSizeHint;
+       }
+}
+
+EXPORT_SYMBOL(ZSTD_DCtxWorkspaceBound);
+EXPORT_SYMBOL(ZSTD_initDCtx);
+EXPORT_SYMBOL(ZSTD_decompressDCtx);
+EXPORT_SYMBOL(ZSTD_decompress_usingDict);
+
+EXPORT_SYMBOL(ZSTD_DDictWorkspaceBound);
+EXPORT_SYMBOL(ZSTD_initDDict);
+EXPORT_SYMBOL(ZSTD_decompress_usingDDict);
+
+EXPORT_SYMBOL(ZSTD_DStreamWorkspaceBound);
+EXPORT_SYMBOL(ZSTD_initDStream);
+EXPORT_SYMBOL(ZSTD_initDStream_usingDDict);
+EXPORT_SYMBOL(ZSTD_resetDStream);
+EXPORT_SYMBOL(ZSTD_decompressStream);
+EXPORT_SYMBOL(ZSTD_DStreamInSize);
+EXPORT_SYMBOL(ZSTD_DStreamOutSize);
+
+EXPORT_SYMBOL(ZSTD_findFrameCompressedSize);
+EXPORT_SYMBOL(ZSTD_getFrameContentSize);
+EXPORT_SYMBOL(ZSTD_findDecompressedSize);
+
+EXPORT_SYMBOL(ZSTD_isFrame);
+EXPORT_SYMBOL(ZSTD_getDictID_fromDict);
+EXPORT_SYMBOL(ZSTD_getDictID_fromDDict);
+EXPORT_SYMBOL(ZSTD_getDictID_fromFrame);
+
+EXPORT_SYMBOL(ZSTD_getFrameParams);
+EXPORT_SYMBOL(ZSTD_decompressBegin);
+EXPORT_SYMBOL(ZSTD_decompressBegin_usingDict);
+EXPORT_SYMBOL(ZSTD_copyDCtx);
+EXPORT_SYMBOL(ZSTD_nextSrcSizeToDecompress);
+EXPORT_SYMBOL(ZSTD_decompressContinue);
+EXPORT_SYMBOL(ZSTD_nextInputType);
+
+EXPORT_SYMBOL(ZSTD_decompressBlock);
+EXPORT_SYMBOL(ZSTD_insertBlock);
+
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_DESCRIPTION("Zstd Decompressor");
diff --git a/grub-core/lib/zstd/entropy_common.c 
b/grub-core/lib/zstd/entropy_common.c
new file mode 100644
index 000000000..2b0a643c3
--- /dev/null
+++ b/grub-core/lib/zstd/entropy_common.c
@@ -0,0 +1,243 @@
+/*
+ * Common functions of New Generation Entropy library
+ * Copyright (C) 2016, Yann Collet.
+ *
+ * BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *   * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * This program is free software; you can redistribute it and/or modify it 
under
+ * the terms of the GNU General Public License version 2 as published by the
+ * Free Software Foundation. This program is dual-licensed; you may select
+ * either version 2 of the GNU General Public License ("GPL") or BSD license
+ * ("BSD").
+ *
+ * You can contact the author at :
+ * - Source repository : https://github.com/Cyan4973/FiniteStateEntropy
+ */
+
+/* *************************************
+*  Dependencies
+***************************************/
+#include "error_private.h" /* ERR_*, ERROR */
+#include "fse.h"
+#include "huf.h"
+#include "mem.h"
+
+/*===   Version   ===*/
+unsigned FSE_versionNumber(void) { return FSE_VERSION_NUMBER; }
+
+/*===   Error Management   ===*/
+unsigned FSE_isError(size_t code) { return ERR_isError(code); }
+
+unsigned HUF_isError(size_t code) { return ERR_isError(code); }
+
+/*-**************************************************************
+*  FSE NCount encoding-decoding
+****************************************************************/
+size_t FSE_readNCount(short *normalizedCounter, unsigned *maxSVPtr, unsigned 
*tableLogPtr, const void *headerBuffer, size_t hbSize)
+{
+       const BYTE *const istart = (const BYTE *)headerBuffer;
+       const BYTE *const iend = istart + hbSize;
+       const BYTE *ip = istart;
+       int nbBits;
+       int remaining;
+       int threshold;
+       U32 bitStream;
+       int bitCount;
+       unsigned charnum = 0;
+       int previous0 = 0;
+
+       if (hbSize < 4)
+               return ERROR(srcSize_wrong);
+       bitStream = ZSTD_readLE32(ip);
+       nbBits = (bitStream & 0xF) + FSE_MIN_TABLELOG; /* extract tableLog */
+       if (nbBits > FSE_TABLELOG_ABSOLUTE_MAX)
+               return ERROR(tableLog_tooLarge);
+       bitStream >>= 4;
+       bitCount = 4;
+       *tableLogPtr = nbBits;
+       remaining = (1 << nbBits) + 1;
+       threshold = 1 << nbBits;
+       nbBits++;
+
+       while ((remaining > 1) & (charnum <= *maxSVPtr)) {
+               if (previous0) {
+                       unsigned n0 = charnum;
+                       while ((bitStream & 0xFFFF) == 0xFFFF) {
+                               n0 += 24;
+                               if (ip < iend - 5) {
+                                       ip += 2;
+                                       bitStream = ZSTD_readLE32(ip) >> 
bitCount;
+                               } else {
+                                       bitStream >>= 16;
+                                       bitCount += 16;
+                               }
+                       }
+                       while ((bitStream & 3) == 3) {
+                               n0 += 3;
+                               bitStream >>= 2;
+                               bitCount += 2;
+                       }
+                       n0 += bitStream & 3;
+                       bitCount += 2;
+                       if (n0 > *maxSVPtr)
+                               return ERROR(maxSymbolValue_tooSmall);
+                       while (charnum < n0)
+                               normalizedCounter[charnum++] = 0;
+                       if ((ip <= iend - 7) || (ip + (bitCount >> 3) <= iend - 
4)) {
+                               ip += bitCount >> 3;
+                               bitCount &= 7;
+                               bitStream = ZSTD_readLE32(ip) >> bitCount;
+                       } else {
+                               bitStream >>= 2;
+                       }
+               }
+               {
+                       int const max = (2 * threshold - 1) - remaining;
+                       int count;
+
+                       if ((bitStream & (threshold - 1)) < (U32)max) {
+                               count = bitStream & (threshold - 1);
+                               bitCount += nbBits - 1;
+                       } else {
+                               count = bitStream & (2 * threshold - 1);
+                               if (count >= threshold)
+                                       count -= max;
+                               bitCount += nbBits;
+                       }
+
+                       count--;                                 /* extra 
accuracy */
+                       remaining -= count < 0 ? -count : count; /* -1 means +1 
*/
+                       normalizedCounter[charnum++] = (short)count;
+                       previous0 = !count;
+                       while (remaining < threshold) {
+                               nbBits--;
+                               threshold >>= 1;
+                       }
+
+                       if ((ip <= iend - 7) || (ip + (bitCount >> 3) <= iend - 
4)) {
+                               ip += bitCount >> 3;
+                               bitCount &= 7;
+                       } else {
+                               bitCount -= (int)(8 * (iend - 4 - ip));
+                               ip = iend - 4;
+                       }
+                       bitStream = ZSTD_readLE32(ip) >> (bitCount & 31);
+               }
+       } /* while ((remaining>1) & (charnum<=*maxSVPtr)) */
+       if (remaining != 1)
+               return ERROR(corruption_detected);
+       if (bitCount > 32)
+               return ERROR(corruption_detected);
+       *maxSVPtr = charnum - 1;
+
+       ip += (bitCount + 7) >> 3;
+       return ip - istart;
+}
+
+/*! HUF_readStats() :
+       Read compact Huffman tree, saved by HUF_writeCTable().
+       `huffWeight` is destination buffer.
+       `rankStats` is assumed to be a table of at least HUF_TABLELOG_MAX U32.
+       @return : size read from `src` , or an error Code .
+       Note : Needed by HUF_readCTable() and HUF_readDTableX?() .
+*/
+size_t HUF_readStats_wksp(BYTE *huffWeight, size_t hwSize, U32 *rankStats, U32 
*nbSymbolsPtr, U32 *tableLogPtr, const void *src, size_t srcSize, void 
*workspace, size_t workspaceSize)
+{
+       U32 weightTotal;
+       const BYTE *ip = (const BYTE *)src;
+       size_t iSize;
+       size_t oSize;
+
+       if (!srcSize)
+               return ERROR(srcSize_wrong);
+       iSize = ip[0];
+       /* memset(huffWeight, 0, hwSize);   */ /* is not necessary, even though 
some analyzer complain ... */
+
+       if (iSize >= 128) { /* special header */
+               oSize = iSize - 127;
+               iSize = ((oSize + 1) / 2);
+               if (iSize + 1 > srcSize)
+                       return ERROR(srcSize_wrong);
+               if (oSize >= hwSize)
+                       return ERROR(corruption_detected);
+               ip += 1;
+               {
+                       U32 n;
+                       for (n = 0; n < oSize; n += 2) {
+                               huffWeight[n] = ip[n / 2] >> 4;
+                               huffWeight[n + 1] = ip[n / 2] & 15;
+                       }
+               }
+       } else {                                                 /* header 
compressed with FSE (normal case) */
+               if (iSize + 1 > srcSize)
+                       return ERROR(srcSize_wrong);
+               oSize = FSE_decompress_wksp(huffWeight, hwSize - 1, ip + 1, 
iSize, 6, workspace, workspaceSize); /* max (hwSize-1) values decoded, as last 
one is implied */
+               if (FSE_isError(oSize))
+                       return oSize;
+       }
+
+       /* collect weight stats */
+       memset(rankStats, 0, (HUF_TABLELOG_MAX + 1) * sizeof(U32));
+       weightTotal = 0;
+       {
+               U32 n;
+               for (n = 0; n < oSize; n++) {
+                       if (huffWeight[n] >= HUF_TABLELOG_MAX)
+                               return ERROR(corruption_detected);
+                       rankStats[huffWeight[n]]++;
+                       weightTotal += (1 << huffWeight[n]) >> 1;
+               }
+       }
+       if (weightTotal == 0)
+               return ERROR(corruption_detected);
+
+       /* get last non-null symbol weight (implied, total must be 2^n) */
+       {
+               U32 const tableLog = BIT_highbit32(weightTotal) + 1;
+               if (tableLog > HUF_TABLELOG_MAX)
+                       return ERROR(corruption_detected);
+               *tableLogPtr = tableLog;
+               /* determine last weight */
+               {
+                       U32 const total = 1 << tableLog;
+                       U32 const rest = total - weightTotal;
+                       U32 const verif = 1 << BIT_highbit32(rest);
+                       U32 const lastWeight = BIT_highbit32(rest) + 1;
+                       if (verif != rest)
+                               return ERROR(corruption_detected); /* last 
value must be a clean power of 2 */
+                       huffWeight[oSize] = (BYTE)lastWeight;
+                       rankStats[lastWeight]++;
+               }
+       }
+
+       /* check tree construction validity */
+       if ((rankStats[1] < 2) || (rankStats[1] & 1))
+               return ERROR(corruption_detected); /* by construction : at 
least 2 elts of rank 1, must be even */
+
+       /* results */
+       *nbSymbolsPtr = (U32)(oSize + 1);
+       return iSize + 1;
+}
diff --git a/grub-core/lib/zstd/error_private.h 
b/grub-core/lib/zstd/error_private.h
new file mode 100644
index 000000000..1a60b31f7
--- /dev/null
+++ b/grub-core/lib/zstd/error_private.h
@@ -0,0 +1,53 @@
+/**
+ * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of https://github.com/facebook/zstd.
+ * An additional grant of patent rights can be found in the PATENTS file in the
+ * same directory.
+ *
+ * This program is free software; you can redistribute it and/or modify it 
under
+ * the terms of the GNU General Public License version 2 as published by the
+ * Free Software Foundation. This program is dual-licensed; you may select
+ * either version 2 of the GNU General Public License ("GPL") or BSD license
+ * ("BSD").
+ */
+
+/* Note : this module is expected to remain private, do not expose it */
+
+#ifndef ERROR_H_MODULE
+#define ERROR_H_MODULE
+
+/* ****************************************
+*  Dependencies
+******************************************/
+#include <linux/types.h> /* size_t */
+#include <linux/zstd.h>  /* enum list */
+
+/* ****************************************
+*  Compiler-specific
+******************************************/
+#define ERR_STATIC static __attribute__((unused))
+
+/*-****************************************
+*  Customization (error_public.h)
+******************************************/
+typedef ZSTD_ErrorCode ERR_enum;
+#define PREFIX(name) ZSTD_error_##name
+
+/*-****************************************
+*  Error codes handling
+******************************************/
+#define ERROR(name) ((size_t)-PREFIX(name))
+
+ERR_STATIC unsigned ERR_isError(size_t code) { return (code > ERROR(maxCode)); 
}
+
+ERR_STATIC ERR_enum ERR_getErrorCode(size_t code)
+{
+       if (!ERR_isError(code))
+               return (ERR_enum)0;
+       return (ERR_enum)(0 - code);
+}
+
+#endif /* ERROR_H_MODULE */
diff --git a/grub-core/lib/zstd/fse.h b/grub-core/lib/zstd/fse.h
new file mode 100644
index 000000000..7460ab04b
--- /dev/null
+++ b/grub-core/lib/zstd/fse.h
@@ -0,0 +1,575 @@
+/*
+ * FSE : Finite State Entropy codec
+ * Public Prototypes declaration
+ * Copyright (C) 2013-2016, Yann Collet.
+ *
+ * BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *   * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * This program is free software; you can redistribute it and/or modify it 
under
+ * the terms of the GNU General Public License version 2 as published by the
+ * Free Software Foundation. This program is dual-licensed; you may select
+ * either version 2 of the GNU General Public License ("GPL") or BSD license
+ * ("BSD").
+ *
+ * You can contact the author at :
+ * - Source repository : https://github.com/Cyan4973/FiniteStateEntropy
+ */
+#ifndef FSE_H
+#define FSE_H
+
+/*-*****************************************
+*  Dependencies
+******************************************/
+#include <linux/types.h> /* size_t, ptrdiff_t */
+
+/*-*****************************************
+*  FSE_PUBLIC_API : control library symbols visibility
+******************************************/
+#define FSE_PUBLIC_API
+
+/*------   Version   ------*/
+#define FSE_VERSION_MAJOR 0
+#define FSE_VERSION_MINOR 9
+#define FSE_VERSION_RELEASE 0
+
+#define FSE_LIB_VERSION FSE_VERSION_MAJOR.FSE_VERSION_MINOR.FSE_VERSION_RELEASE
+#define FSE_QUOTE(str) #str
+#define FSE_EXPAND_AND_QUOTE(str) FSE_QUOTE(str)
+#define FSE_VERSION_STRING FSE_EXPAND_AND_QUOTE(FSE_LIB_VERSION)
+
+#define FSE_VERSION_NUMBER (FSE_VERSION_MAJOR * 100 * 100 + FSE_VERSION_MINOR 
* 100 + FSE_VERSION_RELEASE)
+FSE_PUBLIC_API unsigned FSE_versionNumber(void); /**< library version number; 
to be used when checking dll version */
+
+/*-*****************************************
+*  Tool functions
+******************************************/
+FSE_PUBLIC_API size_t FSE_compressBound(size_t size); /* maximum compressed 
size */
+
+/* Error Management */
+FSE_PUBLIC_API unsigned FSE_isError(size_t code); /* tells if a return value 
is an error code */
+
+/*-*****************************************
+*  FSE detailed API
+******************************************/
+/*!
+FSE_compress() does the following:
+1. count symbol occurrence from source[] into table count[]
+2. normalize counters so that sum(count[]) == Power_of_2 (2^tableLog)
+3. save normalized counters to memory buffer using writeNCount()
+4. build encoding table 'CTable' from normalized counters
+5. encode the data stream using encoding table 'CTable'
+
+FSE_decompress() does the following:
+1. read normalized counters with readNCount()
+2. build decoding table 'DTable' from normalized counters
+3. decode the data stream using decoding table 'DTable'
+
+The following API allows targeting specific sub-functions for advanced tasks.
+For example, it's possible to compress several blocks using the same 'CTable',
+or to save and provide normalized distribution using external method.
+*/
+
+/* *** COMPRESSION *** */
+/*! FSE_optimalTableLog():
+       dynamically downsize 'tableLog' when conditions are met.
+       It saves CPU time, by using smaller tables, while preserving or even 
improving compression ratio.
+       @return : recommended tableLog (necessarily <= 'maxTableLog') */
+FSE_PUBLIC_API unsigned FSE_optimalTableLog(unsigned maxTableLog, size_t 
srcSize, unsigned maxSymbolValue);
+
+/*! FSE_normalizeCount():
+       normalize counts so that sum(count[]) == Power_of_2 (2^tableLog)
+       'normalizedCounter' is a table of short, of minimum size 
(maxSymbolValue+1).
+       @return : tableLog,
+                         or an errorCode, which can be tested using 
FSE_isError() */
+FSE_PUBLIC_API size_t FSE_normalizeCount(short *normalizedCounter, unsigned 
tableLog, const unsigned *count, size_t srcSize, unsigned maxSymbolValue);
+
+/*! FSE_NCountWriteBound():
+       Provides the maximum possible size of an FSE normalized table, given 
'maxSymbolValue' and 'tableLog'.
+       Typically useful for allocation purpose. */
+FSE_PUBLIC_API size_t FSE_NCountWriteBound(unsigned maxSymbolValue, unsigned 
tableLog);
+
+/*! FSE_writeNCount():
+       Compactly save 'normalizedCounter' into 'buffer'.
+       @return : size of the compressed table,
+                         or an errorCode, which can be tested using 
FSE_isError(). */
+FSE_PUBLIC_API size_t FSE_writeNCount(void *buffer, size_t bufferSize, const 
short *normalizedCounter, unsigned maxSymbolValue, unsigned tableLog);
+
+/*! Constructor and Destructor of FSE_CTable.
+       Note that FSE_CTable size depends on 'tableLog' and 'maxSymbolValue' */
+typedef unsigned FSE_CTable; /* don't allocate that. It's only meant to be 
more restrictive than void* */
+
+/*! FSE_compress_usingCTable():
+       Compress `src` using `ct` into `dst` which must be already allocated.
+       @return : size of compressed data (<= `dstCapacity`),
+                         or 0 if compressed data could not fit into `dst`,
+                         or an errorCode, which can be tested using 
FSE_isError() */
+FSE_PUBLIC_API size_t FSE_compress_usingCTable(void *dst, size_t dstCapacity, 
const void *src, size_t srcSize, const FSE_CTable *ct);
+
+/*!
+Tutorial :
+----------
+The first step is to count all symbols. FSE_count() does this job very fast.
+Result will be saved into 'count', a table of unsigned int, which must be 
already allocated, and have 'maxSymbolValuePtr[0]+1' cells.
+'src' is a table of bytes of size 'srcSize'. All values within 'src' MUST be 
<= maxSymbolValuePtr[0]
+maxSymbolValuePtr[0] will be updated, with its real value (necessarily <= 
original value)
+FSE_count() will return the number of occurrence of the most frequent symbol.
+This can be used to know if there is a single symbol within 'src', and to 
quickly evaluate its compressibility.
+If there is an error, the function will return an ErrorCode (which can be 
tested using FSE_isError()).
+
+The next step is to normalize the frequencies.
+FSE_normalizeCount() will ensure that sum of frequencies is == 2 ^'tableLog'.
+It also guarantees a minimum of 1 to any Symbol with frequency >= 1.
+You can use 'tableLog'==0 to mean "use default tableLog value".
+If you are unsure of which tableLog value to use, you can ask 
FSE_optimalTableLog(),
+which will provide the optimal valid tableLog given sourceSize, 
maxSymbolValue, and a user-defined maximum (0 means "default").
+
+The result of FSE_normalizeCount() will be saved into a table,
+called 'normalizedCounter', which is a table of signed short.
+'normalizedCounter' must be already allocated, and have at least 
'maxSymbolValue+1' cells.
+The return value is tableLog if everything proceeded as expected.
+It is 0 if there is a single symbol within distribution.
+If there is an error (ex: invalid tableLog value), the function will return an 
ErrorCode (which can be tested using FSE_isError()).
+
+'normalizedCounter' can be saved in a compact manner to a memory area using 
FSE_writeNCount().
+'buffer' must be already allocated.
+For guaranteed success, buffer size must be at least FSE_headerBound().
+The result of the function is the number of bytes written into 'buffer'.
+If there is an error, the function will return an ErrorCode (which can be 
tested using FSE_isError(); ex : buffer size too small).
+
+'normalizedCounter' can then be used to create the compression table 'CTable'.
+The space required by 'CTable' must be already allocated, using 
FSE_createCTable().
+You can then use FSE_buildCTable() to fill 'CTable'.
+If there is an error, both functions will return an ErrorCode (which can be 
tested using FSE_isError()).
+
+'CTable' can then be used to compress 'src', with FSE_compress_usingCTable().
+Similar to FSE_count(), the convention is that 'src' is assumed to be a table 
of char of size 'srcSize'
+The function returns the size of compressed data (without header), necessarily 
<= `dstCapacity`.
+If it returns '0', compressed data could not fit into 'dst'.
+If there is an error, the function will return an ErrorCode (which can be 
tested using FSE_isError()).
+*/
+
+/* *** DECOMPRESSION *** */
+
+/*! FSE_readNCount():
+       Read compactly saved 'normalizedCounter' from 'rBuffer'.
+       @return : size read from 'rBuffer',
+                         or an errorCode, which can be tested using 
FSE_isError().
+                         maxSymbolValuePtr[0] and tableLogPtr[0] will also be 
updated with their respective values */
+FSE_PUBLIC_API size_t FSE_readNCount(short *normalizedCounter, unsigned 
*maxSymbolValuePtr, unsigned *tableLogPtr, const void *rBuffer, size_t 
rBuffSize);
+
+/*! Constructor and Destructor of FSE_DTable.
+       Note that its size depends on 'tableLog' */
+typedef unsigned FSE_DTable; /* don't allocate that. It's just a way to be 
more restrictive than void* */
+
+/*! FSE_buildDTable():
+       Builds 'dt', which must be already allocated, using FSE_createDTable().
+       return : 0, or an errorCode, which can be tested using FSE_isError() */
+FSE_PUBLIC_API size_t FSE_buildDTable_wksp(FSE_DTable *dt, const short 
*normalizedCounter, unsigned maxSymbolValue, unsigned tableLog, void 
*workspace, size_t workspaceSize);
+
+/*! FSE_decompress_usingDTable():
+       Decompress compressed source `cSrc` of size `cSrcSize` using `dt`
+       into `dst` which must be already allocated.
+       @return : size of regenerated data (necessarily <= `dstCapacity`),
+                         or an errorCode, which can be tested using 
FSE_isError() */
+FSE_PUBLIC_API size_t FSE_decompress_usingDTable(void *dst, size_t 
dstCapacity, const void *cSrc, size_t cSrcSize, const FSE_DTable *dt);
+
+/*!
+Tutorial :
+----------
+(Note : these functions only decompress FSE-compressed blocks.
+ If block is uncompressed, use memcpy() instead
+ If block is a single repeated byte, use memset() instead )
+
+The first step is to obtain the normalized frequencies of symbols.
+This can be performed by FSE_readNCount() if it was saved using 
FSE_writeNCount().
+'normalizedCounter' must be already allocated, and have at least 
'maxSymbolValuePtr[0]+1' cells of signed short.
+In practice, that means it's necessary to know 'maxSymbolValue' beforehand,
+or size the table to handle worst case situations (typically 256).
+FSE_readNCount() will provide 'tableLog' and 'maxSymbolValue'.
+The result of FSE_readNCount() is the number of bytes read from 'rBuffer'.
+Note that 'rBufferSize' must be at least 4 bytes, even if useful information 
is less than that.
+If there is an error, the function will return an error code, which can be 
tested using FSE_isError().
+
+The next step is to build the decompression tables 'FSE_DTable' from 
'normalizedCounter'.
+This is performed by the function FSE_buildDTable().
+The space required by 'FSE_DTable' must be already allocated using 
FSE_createDTable().
+If there is an error, the function will return an error code, which can be 
tested using FSE_isError().
+
+`FSE_DTable` can then be used to decompress `cSrc`, with 
FSE_decompress_usingDTable().
+`cSrcSize` must be strictly correct, otherwise decompression will fail.
+FSE_decompress_usingDTable() result will tell how many bytes were regenerated 
(<=`dstCapacity`).
+If there is an error, the function will return an error code, which can be 
tested using FSE_isError(). (ex: dst buffer too small)
+*/
+
+/* *** Dependency *** */
+#include "bitstream.h"
+
+/* *****************************************
+*  Static allocation
+*******************************************/
+/* FSE buffer bounds */
+#define FSE_NCOUNTBOUND 512
+#define FSE_BLOCKBOUND(size) (size + (size >> 7))
+#define FSE_COMPRESSBOUND(size) (FSE_NCOUNTBOUND + FSE_BLOCKBOUND(size)) /* 
Macro version, useful for static allocation */
+
+/* It is possible to statically allocate FSE CTable/DTable as a table of 
FSE_CTable/FSE_DTable using below macros */
+#define FSE_CTABLE_SIZE_U32(maxTableLog, maxSymbolValue) (1 + (1 << 
(maxTableLog - 1)) + ((maxSymbolValue + 1) * 2))
+#define FSE_DTABLE_SIZE_U32(maxTableLog) (1 + (1 << maxTableLog))
+
+/* *****************************************
+*  FSE advanced API
+*******************************************/
+/* FSE_count_wksp() :
+ * Same as FSE_count(), but using an externally provided scratch buffer.
+ * `workSpace` size must be table of >= `1024` unsigned
+ */
+size_t FSE_count_wksp(unsigned *count, unsigned *maxSymbolValuePtr, const void 
*source, size_t sourceSize, unsigned *workSpace);
+
+/* FSE_countFast_wksp() :
+ * Same as FSE_countFast(), but using an externally provided scratch buffer.
+ * `workSpace` must be a table of minimum `1024` unsigned
+ */
+size_t FSE_countFast_wksp(unsigned *count, unsigned *maxSymbolValuePtr, const 
void *src, size_t srcSize, unsigned *workSpace);
+
+/*! FSE_count_simple
+ * Same as FSE_countFast(), but does not use any additional memory (not even 
on stack).
+ * This function is unsafe, and will segfault if any value within `src` is `> 
*maxSymbolValuePtr` (presuming it's also the size of `count`).
+*/
+size_t FSE_count_simple(unsigned *count, unsigned *maxSymbolValuePtr, const 
void *src, size_t srcSize);
+
+unsigned FSE_optimalTableLog_internal(unsigned maxTableLog, size_t srcSize, 
unsigned maxSymbolValue, unsigned minus);
+/**< same as FSE_optimalTableLog(), which used `minus==2` */
+
+size_t FSE_buildCTable_raw(FSE_CTable *ct, unsigned nbBits);
+/**< build a fake FSE_CTable, designed for a flat distribution, where each 
symbol uses nbBits */
+
+size_t FSE_buildCTable_rle(FSE_CTable *ct, unsigned char symbolValue);
+/**< build a fake FSE_CTable, designed to compress always the same symbolValue 
*/
+
+/* FSE_buildCTable_wksp() :
+ * Same as FSE_buildCTable(), but using an externally allocated scratch buffer 
(`workSpace`).
+ * `wkspSize` must be >= `(1<<tableLog)`.
+ */
+size_t FSE_buildCTable_wksp(FSE_CTable *ct, const short *normalizedCounter, 
unsigned maxSymbolValue, unsigned tableLog, void *workSpace, size_t wkspSize);
+
+size_t FSE_buildDTable_raw(FSE_DTable *dt, unsigned nbBits);
+/**< build a fake FSE_DTable, designed to read a flat distribution where each 
symbol uses nbBits */
+
+size_t FSE_buildDTable_rle(FSE_DTable *dt, unsigned char symbolValue);
+/**< build a fake FSE_DTable, designed to always generate the same symbolValue 
*/
+
+size_t FSE_decompress_wksp(void *dst, size_t dstCapacity, const void *cSrc, 
size_t cSrcSize, unsigned maxLog, void *workspace, size_t workspaceSize);
+/**< same as FSE_decompress(), using an externally allocated `workSpace` 
produced with `FSE_DTABLE_SIZE_U32(maxLog)` */
+
+/* *****************************************
+*  FSE symbol compression API
+*******************************************/
+/*!
+   This API consists of small unitary functions, which highly benefit from 
being inlined.
+   Hence their body are included in next section.
+*/
+typedef struct {
+       ptrdiff_t value;
+       const void *stateTable;
+       const void *symbolTT;
+       unsigned stateLog;
+} FSE_CState_t;
+
+static void FSE_initCState(FSE_CState_t *CStatePtr, const FSE_CTable *ct);
+
+static void FSE_encodeSymbol(BIT_CStream_t *bitC, FSE_CState_t *CStatePtr, 
unsigned symbol);
+
+static void FSE_flushCState(BIT_CStream_t *bitC, const FSE_CState_t 
*CStatePtr);
+
+/**<
+These functions are inner components of FSE_compress_usingCTable().
+They allow the creation of custom streams, mixing multiple tables and bit 
sources.
+
+A key property to keep in mind is that encoding and decoding are done **in 
reverse direction**.
+So the first symbol you will encode is the last you will decode, like a LIFO 
stack.
+
+You will need a few variables to track your CStream. They are :
+
+FSE_CTable    ct;         // Provided by FSE_buildCTable()
+BIT_CStream_t bitStream;  // bitStream tracking structure
+FSE_CState_t  state;      // State tracking structure (can have several)
+
+
+The first thing to do is to init bitStream and state.
+       size_t errorCode = BIT_initCStream(&bitStream, dstBuffer, maxDstSize);
+       FSE_initCState(&state, ct);
+
+Note that BIT_initCStream() can produce an error code, so its result should be 
tested, using FSE_isError();
+You can then encode your input data, byte after byte.
+FSE_encodeSymbol() outputs a maximum of 'tableLog' bits at a time.
+Remember decoding will be done in reverse direction.
+       FSE_encodeByte(&bitStream, &state, symbol);
+
+At any time, you can also add any bit sequence.
+Note : maximum allowed nbBits is 25, for compatibility with 32-bits decoders
+       BIT_addBits(&bitStream, bitField, nbBits);
+
+The above methods don't commit data to memory, they just store it into local 
register, for speed.
+Local register size is 64-bits on 64-bits systems, 32-bits on 32-bits systems 
(size_t).
+Writing data to memory is a manual operation, performed by the flushBits 
function.
+       BIT_flushBits(&bitStream);
+
+Your last FSE encoding operation shall be to flush your last state value(s).
+       FSE_flushState(&bitStream, &state);
+
+Finally, you must close the bitStream.
+The function returns the size of CStream in bytes.
+If data couldn't fit into dstBuffer, it will return a 0 ( == not compressible)
+If there is an error, it returns an errorCode (which can be tested using 
FSE_isError()).
+       size_t size = BIT_closeCStream(&bitStream);
+*/
+
+/* *****************************************
+*  FSE symbol decompression API
+*******************************************/
+typedef struct {
+       size_t state;
+       const void *table; /* precise table may vary, depending on U16 */
+} FSE_DState_t;
+
+static void FSE_initDState(FSE_DState_t *DStatePtr, BIT_DStream_t *bitD, const 
FSE_DTable *dt);
+
+static unsigned char FSE_decodeSymbol(FSE_DState_t *DStatePtr, BIT_DStream_t 
*bitD);
+
+static unsigned FSE_endOfDState(const FSE_DState_t *DStatePtr);
+
+/**<
+Let's now decompose FSE_decompress_usingDTable() into its unitary components.
+You will decode FSE-encoded symbols from the bitStream,
+and also any other bitFields you put in, **in reverse order**.
+
+You will need a few variables to track your bitStream. They are :
+
+BIT_DStream_t DStream;    // Stream context
+FSE_DState_t  DState;     // State context. Multiple ones are possible
+FSE_DTable*   DTablePtr;  // Decoding table, provided by FSE_buildDTable()
+
+The first thing to do is to init the bitStream.
+       errorCode = BIT_initDStream(&DStream, srcBuffer, srcSize);
+
+You should then retrieve your initial state(s)
+(in reverse flushing order if you have several ones) :
+       errorCode = FSE_initDState(&DState, &DStream, DTablePtr);
+
+You can then decode your data, symbol after symbol.
+For information the maximum number of bits read by FSE_decodeSymbol() is 
'tableLog'.
+Keep in mind that symbols are decoded in reverse order, like a LIFO stack 
(last in, first out).
+       unsigned char symbol = FSE_decodeSymbol(&DState, &DStream);
+
+You can retrieve any bitfield you eventually stored into the bitStream (in 
reverse order)
+Note : maximum allowed nbBits is 25, for 32-bits compatibility
+       size_t bitField = BIT_readBits(&DStream, nbBits);
+
+All above operations only read from local register (which size depends on 
size_t).
+Refueling the register from memory is manually performed by the reload method.
+       endSignal = FSE_reloadDStream(&DStream);
+
+BIT_reloadDStream() result tells if there is still some more data to read from 
DStream.
+BIT_DStream_unfinished : there is still some data left into the DStream.
+BIT_DStream_endOfBuffer : Dstream reached end of buffer. Its container may no 
longer be completely filled.
+BIT_DStream_completed : Dstream reached its exact end, corresponding in 
general to decompression completed.
+BIT_DStream_tooFar : Dstream went too far. Decompression result is corrupted.
+
+When reaching end of buffer (BIT_DStream_endOfBuffer), progress slowly, 
notably if you decode multiple symbols per loop,
+to properly detect the exact end of stream.
+After each decoded symbol, check if DStream is fully consumed using this 
simple test :
+       BIT_reloadDStream(&DStream) >= BIT_DStream_completed
+
+When it's done, verify decompression is fully completed, by checking both 
DStream and the relevant states.
+Checking if DStream has reached its end is performed by :
+       BIT_endOfDStream(&DStream);
+Check also the states. There might be some symbols left there, if some high 
probability ones (>50%) are possible.
+       FSE_endOfDState(&DState);
+*/
+
+/* *****************************************
+*  FSE unsafe API
+*******************************************/
+static unsigned char FSE_decodeSymbolFast(FSE_DState_t *DStatePtr, 
BIT_DStream_t *bitD);
+/* faster, but works only if nbBits is always >= 1 (otherwise, result will be 
corrupted) */
+
+/* *****************************************
+*  Implementation of inlined functions
+*******************************************/
+typedef struct {
+       int deltaFindState;
+       U32 deltaNbBits;
+} FSE_symbolCompressionTransform; /* total 8 bytes */
+
+ZSTD_STATIC void FSE_initCState(FSE_CState_t *statePtr, const FSE_CTable *ct)
+{
+       const void *ptr = ct;
+       const U16 *u16ptr = (const U16 *)ptr;
+       const U32 tableLog = ZSTD_read16(ptr);
+       statePtr->value = (ptrdiff_t)1 << tableLog;
+       statePtr->stateTable = u16ptr + 2;
+       statePtr->symbolTT = ((const U32 *)ct + 1 + (tableLog ? (1 << (tableLog 
- 1)) : 1));
+       statePtr->stateLog = tableLog;
+}
+
+/*! FSE_initCState2() :
+*   Same as FSE_initCState(), but the first symbol to include (which will be 
the last to be read)
+*   uses the smallest state value possible, saving the cost of this symbol */
+ZSTD_STATIC void FSE_initCState2(FSE_CState_t *statePtr, const FSE_CTable *ct, 
U32 symbol)
+{
+       FSE_initCState(statePtr, ct);
+       {
+               const FSE_symbolCompressionTransform symbolTT = ((const 
FSE_symbolCompressionTransform *)(statePtr->symbolTT))[symbol];
+               const U16 *stateTable = (const U16 *)(statePtr->stateTable);
+               U32 nbBitsOut = (U32)((symbolTT.deltaNbBits + (1 << 15)) >> 16);
+               statePtr->value = (nbBitsOut << 16) - symbolTT.deltaNbBits;
+               statePtr->value = stateTable[(statePtr->value >> nbBitsOut) + 
symbolTT.deltaFindState];
+       }
+}
+
+ZSTD_STATIC void FSE_encodeSymbol(BIT_CStream_t *bitC, FSE_CState_t *statePtr, 
U32 symbol)
+{
+       const FSE_symbolCompressionTransform symbolTT = ((const 
FSE_symbolCompressionTransform *)(statePtr->symbolTT))[symbol];
+       const U16 *const stateTable = (const U16 *)(statePtr->stateTable);
+       U32 nbBitsOut = (U32)((statePtr->value + symbolTT.deltaNbBits) >> 16);
+       BIT_addBits(bitC, statePtr->value, nbBitsOut);
+       statePtr->value = stateTable[(statePtr->value >> nbBitsOut) + 
symbolTT.deltaFindState];
+}
+
+ZSTD_STATIC void FSE_flushCState(BIT_CStream_t *bitC, const FSE_CState_t 
*statePtr)
+{
+       BIT_addBits(bitC, statePtr->value, statePtr->stateLog);
+       BIT_flushBits(bitC);
+}
+
+/* ======    Decompression    ====== */
+
+typedef struct {
+       U16 tableLog;
+       U16 fastMode;
+} FSE_DTableHeader; /* sizeof U32 */
+
+typedef struct {
+       unsigned short newState;
+       unsigned char symbol;
+       unsigned char nbBits;
+} FSE_decode_t; /* size == U32 */
+
+ZSTD_STATIC void FSE_initDState(FSE_DState_t *DStatePtr, BIT_DStream_t *bitD, 
const FSE_DTable *dt)
+{
+       const void *ptr = dt;
+       const FSE_DTableHeader *const DTableH = (const FSE_DTableHeader *)ptr;
+       DStatePtr->state = BIT_readBits(bitD, DTableH->tableLog);
+       BIT_reloadDStream(bitD);
+       DStatePtr->table = dt + 1;
+}
+
+ZSTD_STATIC BYTE FSE_peekSymbol(const FSE_DState_t *DStatePtr)
+{
+       FSE_decode_t const DInfo = ((const FSE_decode_t 
*)(DStatePtr->table))[DStatePtr->state];
+       return DInfo.symbol;
+}
+
+ZSTD_STATIC void FSE_updateState(FSE_DState_t *DStatePtr, BIT_DStream_t *bitD)
+{
+       FSE_decode_t const DInfo = ((const FSE_decode_t 
*)(DStatePtr->table))[DStatePtr->state];
+       U32 const nbBits = DInfo.nbBits;
+       size_t const lowBits = BIT_readBits(bitD, nbBits);
+       DStatePtr->state = DInfo.newState + lowBits;
+}
+
+ZSTD_STATIC BYTE FSE_decodeSymbol(FSE_DState_t *DStatePtr, BIT_DStream_t *bitD)
+{
+       FSE_decode_t const DInfo = ((const FSE_decode_t 
*)(DStatePtr->table))[DStatePtr->state];
+       U32 const nbBits = DInfo.nbBits;
+       BYTE const symbol = DInfo.symbol;
+       size_t const lowBits = BIT_readBits(bitD, nbBits);
+
+       DStatePtr->state = DInfo.newState + lowBits;
+       return symbol;
+}
+
+/*! FSE_decodeSymbolFast() :
+       unsafe, only works if no symbol has a probability > 50% */
+ZSTD_STATIC BYTE FSE_decodeSymbolFast(FSE_DState_t *DStatePtr, BIT_DStream_t 
*bitD)
+{
+       FSE_decode_t const DInfo = ((const FSE_decode_t 
*)(DStatePtr->table))[DStatePtr->state];
+       U32 const nbBits = DInfo.nbBits;
+       BYTE const symbol = DInfo.symbol;
+       size_t const lowBits = BIT_readBitsFast(bitD, nbBits);
+
+       DStatePtr->state = DInfo.newState + lowBits;
+       return symbol;
+}
+
+ZSTD_STATIC unsigned FSE_endOfDState(const FSE_DState_t *DStatePtr) { return 
DStatePtr->state == 0; }
+
+/* **************************************************************
+*  Tuning parameters
+****************************************************************/
+/*!MEMORY_USAGE :
+*  Memory usage formula : N->2^N Bytes (examples : 10 -> 1KB; 12 -> 4KB ; 16 
-> 64KB; 20 -> 1MB; etc.)
+*  Increasing memory usage improves compression ratio
+*  Reduced memory usage can improve speed, due to cache effect
+*  Recommended max value is 14, for 16KB, which nicely fits into Intel x86 L1 
cache */
+#ifndef FSE_MAX_MEMORY_USAGE
+#define FSE_MAX_MEMORY_USAGE 14
+#endif
+#ifndef FSE_DEFAULT_MEMORY_USAGE
+#define FSE_DEFAULT_MEMORY_USAGE 13
+#endif
+
+/*!FSE_MAX_SYMBOL_VALUE :
+*  Maximum symbol value authorized.
+*  Required for proper stack allocation */
+#ifndef FSE_MAX_SYMBOL_VALUE
+#define FSE_MAX_SYMBOL_VALUE 255
+#endif
+
+/* **************************************************************
+*  template functions type & suffix
+****************************************************************/
+#define FSE_FUNCTION_TYPE BYTE
+#define FSE_FUNCTION_EXTENSION
+#define FSE_DECODE_TYPE FSE_decode_t
+
+/* ***************************************************************
+*  Constants
+*****************************************************************/
+#define FSE_MAX_TABLELOG (FSE_MAX_MEMORY_USAGE - 2)
+#define FSE_MAX_TABLESIZE (1U << FSE_MAX_TABLELOG)
+#define FSE_MAXTABLESIZE_MASK (FSE_MAX_TABLESIZE - 1)
+#define FSE_DEFAULT_TABLELOG (FSE_DEFAULT_MEMORY_USAGE - 2)
+#define FSE_MIN_TABLELOG 5
+
+#define FSE_TABLELOG_ABSOLUTE_MAX 15
+#if FSE_MAX_TABLELOG > FSE_TABLELOG_ABSOLUTE_MAX
+#error "FSE_MAX_TABLELOG > FSE_TABLELOG_ABSOLUTE_MAX is not supported"
+#endif
+
+#define FSE_TABLESTEP(tableSize) ((tableSize >> 1) + (tableSize >> 3) + 3)
+
+#endif /* FSE_H */
diff --git a/grub-core/lib/zstd/fse_decompress.c 
b/grub-core/lib/zstd/fse_decompress.c
new file mode 100644
index 000000000..a84300e5a
--- /dev/null
+++ b/grub-core/lib/zstd/fse_decompress.c
@@ -0,0 +1,332 @@
+/*
+ * FSE : Finite State Entropy decoder
+ * Copyright (C) 2013-2015, Yann Collet.
+ *
+ * BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *   * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * This program is free software; you can redistribute it and/or modify it 
under
+ * the terms of the GNU General Public License version 2 as published by the
+ * Free Software Foundation. This program is dual-licensed; you may select
+ * either version 2 of the GNU General Public License ("GPL") or BSD license
+ * ("BSD").
+ *
+ * You can contact the author at :
+ * - Source repository : https://github.com/Cyan4973/FiniteStateEntropy
+ */
+
+/* **************************************************************
+*  Compiler specifics
+****************************************************************/
+#define FORCE_INLINE static __always_inline
+
+/* **************************************************************
+*  Includes
+****************************************************************/
+#include "bitstream.h"
+#include "fse.h"
+#include <linux/compiler.h>
+#include <linux/kernel.h>
+#include <linux/string.h> /* memcpy, memset */
+
+/* **************************************************************
+*  Error Management
+****************************************************************/
+#define FSE_isError ERR_isError
+#define FSE_STATIC_ASSERT(c)                                   \
+       {                                                      \
+               enum { FSE_static_assert = 1 / (int)(!!(c)) }; \
+       } /* use only *after* variable declarations */
+
+/* check and forward error code */
+#define CHECK_F(f)                  \
+       {                           \
+               size_t const e = f; \
+               if (FSE_isError(e)) \
+                       return e;   \
+       }
+
+/* **************************************************************
+*  Templates
+****************************************************************/
+/*
+  designed to be included
+  for type-specific functions (template emulation in C)
+  Objective is to write these functions only once, for improved maintenance
+*/
+
+/* safety checks */
+#ifndef FSE_FUNCTION_EXTENSION
+#error "FSE_FUNCTION_EXTENSION must be defined"
+#endif
+#ifndef FSE_FUNCTION_TYPE
+#error "FSE_FUNCTION_TYPE must be defined"
+#endif
+
+/* Function names */
+#define FSE_CAT(X, Y) X##Y
+#define FSE_FUNCTION_NAME(X, Y) FSE_CAT(X, Y)
+#define FSE_TYPE_NAME(X, Y) FSE_CAT(X, Y)
+
+/* Function templates */
+
+size_t FSE_buildDTable_wksp(FSE_DTable *dt, const short *normalizedCounter, 
unsigned maxSymbolValue, unsigned tableLog, void *workspace, size_t 
workspaceSize)
+{
+       void *const tdPtr = dt + 1; /* because *dt is unsigned, 32-bits aligned 
on 32-bits */
+       FSE_DECODE_TYPE *const tableDecode = (FSE_DECODE_TYPE *)(tdPtr);
+       U16 *symbolNext = (U16 *)workspace;
+
+       U32 const maxSV1 = maxSymbolValue + 1;
+       U32 const tableSize = 1 << tableLog;
+       U32 highThreshold = tableSize - 1;
+
+       /* Sanity Checks */
+       if (workspaceSize < sizeof(U16) * (FSE_MAX_SYMBOL_VALUE + 1))
+               return ERROR(tableLog_tooLarge);
+       if (maxSymbolValue > FSE_MAX_SYMBOL_VALUE)
+               return ERROR(maxSymbolValue_tooLarge);
+       if (tableLog > FSE_MAX_TABLELOG)
+               return ERROR(tableLog_tooLarge);
+
+       /* Init, lay down lowprob symbols */
+       {
+               FSE_DTableHeader DTableH;
+               DTableH.tableLog = (U16)tableLog;
+               DTableH.fastMode = 1;
+               {
+                       S16 const largeLimit = (S16)(1 << (tableLog - 1));
+                       U32 s;
+                       for (s = 0; s < maxSV1; s++) {
+                               if (normalizedCounter[s] == -1) {
+                                       tableDecode[highThreshold--].symbol = 
(FSE_FUNCTION_TYPE)s;
+                                       symbolNext[s] = 1;
+                               } else {
+                                       if (normalizedCounter[s] >= largeLimit)
+                                               DTableH.fastMode = 0;
+                                       symbolNext[s] = normalizedCounter[s];
+                               }
+                       }
+               }
+               memcpy(dt, &DTableH, sizeof(DTableH));
+       }
+
+       /* Spread symbols */
+       {
+               U32 const tableMask = tableSize - 1;
+               U32 const step = FSE_TABLESTEP(tableSize);
+               U32 s, position = 0;
+               for (s = 0; s < maxSV1; s++) {
+                       int i;
+                       for (i = 0; i < normalizedCounter[s]; i++) {
+                               tableDecode[position].symbol = 
(FSE_FUNCTION_TYPE)s;
+                               position = (position + step) & tableMask;
+                               while (position > highThreshold)
+                                       position = (position + step) & 
tableMask; /* lowprob area */
+                       }
+               }
+               if (position != 0)
+                       return ERROR(GENERIC); /* position must reach all cells 
once, otherwise normalizedCounter is incorrect */
+       }
+
+       /* Build Decoding table */
+       {
+               U32 u;
+               for (u = 0; u < tableSize; u++) {
+                       FSE_FUNCTION_TYPE const symbol = 
(FSE_FUNCTION_TYPE)(tableDecode[u].symbol);
+                       U16 nextState = symbolNext[symbol]++;
+                       tableDecode[u].nbBits = (BYTE)(tableLog - 
BIT_highbit32((U32)nextState));
+                       tableDecode[u].newState = (U16)((nextState << 
tableDecode[u].nbBits) - tableSize);
+               }
+       }
+
+       return 0;
+}
+
+/*-*******************************************************
+*  Decompression (Byte symbols)
+*********************************************************/
+size_t FSE_buildDTable_rle(FSE_DTable *dt, BYTE symbolValue)
+{
+       void *ptr = dt;
+       FSE_DTableHeader *const DTableH = (FSE_DTableHeader *)ptr;
+       void *dPtr = dt + 1;
+       FSE_decode_t *const cell = (FSE_decode_t *)dPtr;
+
+       DTableH->tableLog = 0;
+       DTableH->fastMode = 0;
+
+       cell->newState = 0;
+       cell->symbol = symbolValue;
+       cell->nbBits = 0;
+
+       return 0;
+}
+
+size_t FSE_buildDTable_raw(FSE_DTable *dt, unsigned nbBits)
+{
+       void *ptr = dt;
+       FSE_DTableHeader *const DTableH = (FSE_DTableHeader *)ptr;
+       void *dPtr = dt + 1;
+       FSE_decode_t *const dinfo = (FSE_decode_t *)dPtr;
+       const unsigned tableSize = 1 << nbBits;
+       const unsigned tableMask = tableSize - 1;
+       const unsigned maxSV1 = tableMask + 1;
+       unsigned s;
+
+       /* Sanity checks */
+       if (nbBits < 1)
+               return ERROR(GENERIC); /* min size */
+
+       /* Build Decoding Table */
+       DTableH->tableLog = (U16)nbBits;
+       DTableH->fastMode = 1;
+       for (s = 0; s < maxSV1; s++) {
+               dinfo[s].newState = 0;
+               dinfo[s].symbol = (BYTE)s;
+               dinfo[s].nbBits = (BYTE)nbBits;
+       }
+
+       return 0;
+}
+
+FORCE_INLINE size_t FSE_decompress_usingDTable_generic(void *dst, size_t 
maxDstSize, const void *cSrc, size_t cSrcSize, const FSE_DTable *dt,
+                                                      const unsigned fast)
+{
+       BYTE *const ostart = (BYTE *)dst;
+       BYTE *op = ostart;
+       BYTE *const omax = op + maxDstSize;
+       BYTE *const olimit = omax - 3;
+
+       BIT_DStream_t bitD;
+       FSE_DState_t state1;
+       FSE_DState_t state2;
+
+       /* Init */
+       CHECK_F(BIT_initDStream(&bitD, cSrc, cSrcSize));
+
+       FSE_initDState(&state1, &bitD, dt);
+       FSE_initDState(&state2, &bitD, dt);
+
+#define FSE_GETSYMBOL(statePtr) fast ? FSE_decodeSymbolFast(statePtr, &bitD) : 
FSE_decodeSymbol(statePtr, &bitD)
+
+       /* 4 symbols per loop */
+       for (; (BIT_reloadDStream(&bitD) == BIT_DStream_unfinished) & (op < 
olimit); op += 4) {
+               op[0] = FSE_GETSYMBOL(&state1);
+
+               if (FSE_MAX_TABLELOG * 2 + 7 > sizeof(bitD.bitContainer) * 8) 
/* This test must be static */
+                       BIT_reloadDStream(&bitD);
+
+               op[1] = FSE_GETSYMBOL(&state2);
+
+               if (FSE_MAX_TABLELOG * 4 + 7 > sizeof(bitD.bitContainer) * 8) 
/* This test must be static */
+               {
+                       if (BIT_reloadDStream(&bitD) > BIT_DStream_unfinished) {
+                               op += 2;
+                               break;
+                       }
+               }
+
+               op[2] = FSE_GETSYMBOL(&state1);
+
+               if (FSE_MAX_TABLELOG * 2 + 7 > sizeof(bitD.bitContainer) * 8) 
/* This test must be static */
+                       BIT_reloadDStream(&bitD);
+
+               op[3] = FSE_GETSYMBOL(&state2);
+       }
+
+       /* tail */
+       /* note : BIT_reloadDStream(&bitD) >= FSE_DStream_partiallyFilled; Ends 
at exactly BIT_DStream_completed */
+       while (1) {
+               if (op > (omax - 2))
+                       return ERROR(dstSize_tooSmall);
+               *op++ = FSE_GETSYMBOL(&state1);
+               if (BIT_reloadDStream(&bitD) == BIT_DStream_overflow) {
+                       *op++ = FSE_GETSYMBOL(&state2);
+                       break;
+               }
+
+               if (op > (omax - 2))
+                       return ERROR(dstSize_tooSmall);
+               *op++ = FSE_GETSYMBOL(&state2);
+               if (BIT_reloadDStream(&bitD) == BIT_DStream_overflow) {
+                       *op++ = FSE_GETSYMBOL(&state1);
+                       break;
+               }
+       }
+
+       return op - ostart;
+}
+
+size_t FSE_decompress_usingDTable(void *dst, size_t originalSize, const void 
*cSrc, size_t cSrcSize, const FSE_DTable *dt)
+{
+       const void *ptr = dt;
+       const FSE_DTableHeader *DTableH = (const FSE_DTableHeader *)ptr;
+       const U32 fastMode = DTableH->fastMode;
+
+       /* select fast mode (static) */
+       if (fastMode)
+               return FSE_decompress_usingDTable_generic(dst, originalSize, 
cSrc, cSrcSize, dt, 1);
+       return FSE_decompress_usingDTable_generic(dst, originalSize, cSrc, 
cSrcSize, dt, 0);
+}
+
+size_t FSE_decompress_wksp(void *dst, size_t dstCapacity, const void *cSrc, 
size_t cSrcSize, unsigned maxLog, void *workspace, size_t workspaceSize)
+{
+       const BYTE *const istart = (const BYTE *)cSrc;
+       const BYTE *ip = istart;
+       unsigned tableLog;
+       unsigned maxSymbolValue = FSE_MAX_SYMBOL_VALUE;
+       size_t NCountLength;
+
+       FSE_DTable *dt;
+       short *counting;
+       size_t spaceUsed32 = 0;
+
+       FSE_STATIC_ASSERT(sizeof(FSE_DTable) == sizeof(U32));
+
+       dt = (FSE_DTable *)((U32 *)workspace + spaceUsed32);
+       spaceUsed32 += FSE_DTABLE_SIZE_U32(maxLog);
+       counting = (short *)((U32 *)workspace + spaceUsed32);
+       spaceUsed32 += ALIGN(sizeof(short) * (FSE_MAX_SYMBOL_VALUE + 1), 
sizeof(U32)) >> 2;
+
+       if ((spaceUsed32 << 2) > workspaceSize)
+               return ERROR(tableLog_tooLarge);
+       workspace = (U32 *)workspace + spaceUsed32;
+       workspaceSize -= (spaceUsed32 << 2);
+
+       /* normal FSE decoding mode */
+       NCountLength = FSE_readNCount(counting, &maxSymbolValue, &tableLog, 
istart, cSrcSize);
+       if (FSE_isError(NCountLength))
+               return NCountLength;
+       // if (NCountLength >= cSrcSize) return ERROR(srcSize_wrong);   /* too 
small input size; supposed to be already checked in NCountLength, only remaining
+       // case : NCountLength==cSrcSize */
+       if (tableLog > maxLog)
+               return ERROR(tableLog_tooLarge);
+       ip += NCountLength;
+       cSrcSize -= NCountLength;
+
+       CHECK_F(FSE_buildDTable_wksp(dt, counting, maxSymbolValue, tableLog, 
workspace, workspaceSize));
+
+       return FSE_decompress_usingDTable(dst, dstCapacity, ip, cSrcSize, dt); 
/* always return, even if it is an error code */
+}
diff --git a/grub-core/lib/zstd/huf.h b/grub-core/lib/zstd/huf.h
new file mode 100644
index 000000000..2143da28d
--- /dev/null
+++ b/grub-core/lib/zstd/huf.h
@@ -0,0 +1,212 @@
+/*
+ * Huffman coder, part of New Generation Entropy library
+ * header file
+ * Copyright (C) 2013-2016, Yann Collet.
+ *
+ * BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *   * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * This program is free software; you can redistribute it and/or modify it 
under
+ * the terms of the GNU General Public License version 2 as published by the
+ * Free Software Foundation. This program is dual-licensed; you may select
+ * either version 2 of the GNU General Public License ("GPL") or BSD license
+ * ("BSD").
+ *
+ * You can contact the author at :
+ * - Source repository : https://github.com/Cyan4973/FiniteStateEntropy
+ */
+#ifndef HUF_H_298734234
+#define HUF_H_298734234
+
+/* *** Dependencies *** */
+#include <linux/types.h> /* size_t */
+
+/* ***   Tool functions *** */
+#define HUF_BLOCKSIZE_MAX (128 * 1024) /**< maximum input size for a single 
block compressed with HUF_compress */
+size_t HUF_compressBound(size_t size); /**< maximum compressed size (worst 
case) */
+
+/* Error Management */
+unsigned HUF_isError(size_t code); /**< tells if a return value is an error 
code */
+
+/* ***   Advanced function   *** */
+
+/** HUF_compress4X_wksp() :
+*   Same as HUF_compress2(), but uses externally allocated `workSpace`, which 
must be a table of >= 1024 unsigned */
+size_t HUF_compress4X_wksp(void *dst, size_t dstSize, const void *src, size_t 
srcSize, unsigned maxSymbolValue, unsigned tableLog, void *workSpace,
+                          size_t wkspSize); /**< `workSpace` must be a table 
of at least HUF_COMPRESS_WORKSPACE_SIZE_U32 unsigned */
+
+/* *** Dependencies *** */
+#include "mem.h" /* U32 */
+
+/* *** Constants *** */
+#define HUF_TABLELOG_MAX 12     /* max configured tableLog (for static 
allocation); can be modified up to HUF_ABSOLUTEMAX_TABLELOG */
+#define HUF_TABLELOG_DEFAULT 11 /* tableLog by default, when not specified */
+#define HUF_SYMBOLVALUE_MAX 255
+
+#define HUF_TABLELOG_ABSOLUTEMAX 15 /* absolute limit of HUF_MAX_TABLELOG. 
Beyond that value, code does not work */
+#if (HUF_TABLELOG_MAX > HUF_TABLELOG_ABSOLUTEMAX)
+#error "HUF_TABLELOG_MAX is too large !"
+#endif
+
+/* ****************************************
+*  Static allocation
+******************************************/
+/* HUF buffer bounds */
+#define HUF_CTABLEBOUND 129
+#define HUF_BLOCKBOUND(size) (size + (size >> 8) + 8)                   /* 
only true if incompressible pre-filtered with fast heuristic */
+#define HUF_COMPRESSBOUND(size) (HUF_CTABLEBOUND + HUF_BLOCKBOUND(size)) /* 
Macro version, useful for static allocation */
+
+/* static allocation of HUF's Compression Table */
+#define HUF_CREATE_STATIC_CTABLE(name, maxSymbolValue) \
+       U32 name##hb[maxSymbolValue + 1];              \
+       void *name##hv = &(name##hb);                  \
+       HUF_CElt *name = (HUF_CElt *)(name##hv) /* no final ; */
+
+/* static allocation of HUF's DTable */
+typedef U32 HUF_DTable;
+#define HUF_DTABLE_SIZE(maxTableLog) (1 + (1 << (maxTableLog)))
+#define HUF_CREATE_STATIC_DTABLEX2(DTable, maxTableLog) HUF_DTable 
DTable[HUF_DTABLE_SIZE((maxTableLog)-1)] = {((U32)((maxTableLog)-1) * 
0x01000001)}
+#define HUF_CREATE_STATIC_DTABLEX4(DTable, maxTableLog) HUF_DTable 
DTable[HUF_DTABLE_SIZE(maxTableLog)] = {((U32)(maxTableLog)*0x01000001)}
+
+/* The workspace must have alignment at least 4 and be at least this large */
+#define HUF_COMPRESS_WORKSPACE_SIZE (6 << 10)
+#define HUF_COMPRESS_WORKSPACE_SIZE_U32 (HUF_COMPRESS_WORKSPACE_SIZE / 
sizeof(U32))
+
+/* The workspace must have alignment at least 4 and be at least this large */
+#define HUF_DECOMPRESS_WORKSPACE_SIZE (3 << 10)
+#define HUF_DECOMPRESS_WORKSPACE_SIZE_U32 (HUF_DECOMPRESS_WORKSPACE_SIZE / 
sizeof(U32))
+
+/* ****************************************
+*  Advanced decompression functions
+******************************************/
+size_t HUF_decompress4X_DCtx_wksp(HUF_DTable *dctx, void *dst, size_t dstSize, 
const void *cSrc, size_t cSrcSize, void *workspace, size_t workspaceSize); /**< 
decodes RLE and uncompressed */
+size_t HUF_decompress4X_hufOnly_wksp(HUF_DTable *dctx, void *dst, size_t 
dstSize, const void *cSrc, size_t cSrcSize, void *workspace,
+                               size_t workspaceSize);                          
                               /**< considers RLE and uncompressed as errors */
+size_t HUF_decompress4X2_DCtx_wksp(HUF_DTable *dctx, void *dst, size_t 
dstSize, const void *cSrc, size_t cSrcSize, void *workspace,
+                                  size_t workspaceSize); /**< single-symbol 
decoder */
+size_t HUF_decompress4X4_DCtx_wksp(HUF_DTable *dctx, void *dst, size_t 
dstSize, const void *cSrc, size_t cSrcSize, void *workspace,
+                                  size_t workspaceSize); /**< double-symbols 
decoder */
+
+/* ****************************************
+*  HUF detailed API
+******************************************/
+/*!
+HUF_compress() does the following:
+1. count symbol occurrence from source[] into table count[] using FSE_count()
+2. (optional) refine tableLog using HUF_optimalTableLog()
+3. build Huffman table from count using HUF_buildCTable()
+4. save Huffman table to memory buffer using HUF_writeCTable_wksp()
+5. encode the data stream using HUF_compress4X_usingCTable()
+
+The following API allows targeting specific sub-functions for advanced tasks.
+For example, it's possible to compress several blocks using the same 'CTable',
+or to save and regenerate 'CTable' using external methods.
+*/
+/* FSE_count() : find it within "fse.h" */
+unsigned HUF_optimalTableLog(unsigned maxTableLog, size_t srcSize, unsigned 
maxSymbolValue);
+typedef struct HUF_CElt_s HUF_CElt; /* incomplete type */
+size_t HUF_writeCTable_wksp(void *dst, size_t maxDstSize, const HUF_CElt 
*CTable, unsigned maxSymbolValue, unsigned huffLog, void *workspace, size_t 
workspaceSize);
+size_t HUF_compress4X_usingCTable(void *dst, size_t dstSize, const void *src, 
size_t srcSize, const HUF_CElt *CTable);
+
+typedef enum {
+       HUF_repeat_none,  /**< Cannot use the previous table */
+       HUF_repeat_check, /**< Can use the previous table but it must be 
checked. Note : The previous table must have been constructed by HUF_compress{1,
+                            4}X_repeat */
+       HUF_repeat_valid  /**< Can use the previous table and it is asumed to 
be valid */
+} HUF_repeat;
+/** HUF_compress4X_repeat() :
+*   Same as HUF_compress4X_wksp(), but considers using hufTable if *repeat != 
HUF_repeat_none.
+*   If it uses hufTable it does not modify hufTable or repeat.
+*   If it doesn't, it sets *repeat = HUF_repeat_none, and it sets hufTable to 
the table used.
+*   If preferRepeat then the old table will always be used if valid. */
+size_t HUF_compress4X_repeat(void *dst, size_t dstSize, const void *src, 
size_t srcSize, unsigned maxSymbolValue, unsigned tableLog, void *workSpace,
+                            size_t wkspSize, HUF_CElt *hufTable, HUF_repeat 
*repeat,
+                            int preferRepeat); /**< `workSpace` must be a 
table of at least HUF_COMPRESS_WORKSPACE_SIZE_U32 unsigned */
+
+/** HUF_buildCTable_wksp() :
+ *  Same as HUF_buildCTable(), but using externally allocated scratch buffer.
+ *  `workSpace` must be aligned on 4-bytes boundaries, and be at least as 
large as a table of 1024 unsigned.
+ */
+size_t HUF_buildCTable_wksp(HUF_CElt *tree, const U32 *count, U32 
maxSymbolValue, U32 maxNbBits, void *workSpace, size_t wkspSize);
+
+/*! HUF_readStats() :
+       Read compact Huffman tree, saved by HUF_writeCTable().
+       `huffWeight` is destination buffer.
+       @return : size read from `src` , or an error Code .
+       Note : Needed by HUF_readCTable() and HUF_readDTableXn() . */
+size_t HUF_readStats_wksp(BYTE *huffWeight, size_t hwSize, U32 *rankStats, U32 
*nbSymbolsPtr, U32 *tableLogPtr, const void *src, size_t srcSize,
+                         void *workspace, size_t workspaceSize);
+
+/** HUF_readCTable() :
+*   Loading a CTable saved with HUF_writeCTable() */
+size_t HUF_readCTable_wksp(HUF_CElt *CTable, unsigned maxSymbolValue, const 
void *src, size_t srcSize, void *workspace, size_t workspaceSize);
+
+/*
+HUF_decompress() does the following:
+1. select the decompression algorithm (X2, X4) based on pre-computed heuristics
+2. build Huffman table from save, using HUF_readDTableXn()
+3. decode 1 or 4 segments in parallel using HUF_decompressSXn_usingDTable
+*/
+
+/** HUF_selectDecoder() :
+*   Tells which decoder is likely to decode faster,
+*   based on a set of pre-determined metrics.
+*   @return : 0==HUF_decompress4X2, 1==HUF_decompress4X4 .
+*   Assumption : 0 < cSrcSize < dstSize <= 128 KB */
+U32 HUF_selectDecoder(size_t dstSize, size_t cSrcSize);
+
+size_t HUF_readDTableX2_wksp(HUF_DTable *DTable, const void *src, size_t 
srcSize, void *workspace, size_t workspaceSize);
+size_t HUF_readDTableX4_wksp(HUF_DTable *DTable, const void *src, size_t 
srcSize, void *workspace, size_t workspaceSize);
+
+size_t HUF_decompress4X_usingDTable(void *dst, size_t maxDstSize, const void 
*cSrc, size_t cSrcSize, const HUF_DTable *DTable);
+size_t HUF_decompress4X2_usingDTable(void *dst, size_t maxDstSize, const void 
*cSrc, size_t cSrcSize, const HUF_DTable *DTable);
+size_t HUF_decompress4X4_usingDTable(void *dst, size_t maxDstSize, const void 
*cSrc, size_t cSrcSize, const HUF_DTable *DTable);
+
+/* single stream variants */
+
+size_t HUF_compress1X_wksp(void *dst, size_t dstSize, const void *src, size_t 
srcSize, unsigned maxSymbolValue, unsigned tableLog, void *workSpace,
+                          size_t wkspSize); /**< `workSpace` must be a table 
of at least HUF_COMPRESS_WORKSPACE_SIZE_U32 unsigned */
+size_t HUF_compress1X_usingCTable(void *dst, size_t dstSize, const void *src, 
size_t srcSize, const HUF_CElt *CTable);
+/** HUF_compress1X_repeat() :
+*   Same as HUF_compress1X_wksp(), but considers using hufTable if *repeat != 
HUF_repeat_none.
+*   If it uses hufTable it does not modify hufTable or repeat.
+*   If it doesn't, it sets *repeat = HUF_repeat_none, and it sets hufTable to 
the table used.
+*   If preferRepeat then the old table will always be used if valid. */
+size_t HUF_compress1X_repeat(void *dst, size_t dstSize, const void *src, 
size_t srcSize, unsigned maxSymbolValue, unsigned tableLog, void *workSpace,
+                            size_t wkspSize, HUF_CElt *hufTable, HUF_repeat 
*repeat,
+                            int preferRepeat); /**< `workSpace` must be a 
table of at least HUF_COMPRESS_WORKSPACE_SIZE_U32 unsigned */
+
+size_t HUF_decompress1X_DCtx_wksp(HUF_DTable *dctx, void *dst, size_t dstSize, 
const void *cSrc, size_t cSrcSize, void *workspace, size_t workspaceSize);
+size_t HUF_decompress1X2_DCtx_wksp(HUF_DTable *dctx, void *dst, size_t 
dstSize, const void *cSrc, size_t cSrcSize, void *workspace,
+                                  size_t workspaceSize); /**< single-symbol 
decoder */
+size_t HUF_decompress1X4_DCtx_wksp(HUF_DTable *dctx, void *dst, size_t 
dstSize, const void *cSrc, size_t cSrcSize, void *workspace,
+                                  size_t workspaceSize); /**< double-symbols 
decoder */
+
+size_t HUF_decompress1X_usingDTable(void *dst, size_t maxDstSize, const void 
*cSrc, size_t cSrcSize,
+                                   const HUF_DTable *DTable); /**< automatic 
selection of sing or double symbol decoder, based on DTable */
+size_t HUF_decompress1X2_usingDTable(void *dst, size_t maxDstSize, const void 
*cSrc, size_t cSrcSize, const HUF_DTable *DTable);
+size_t HUF_decompress1X4_usingDTable(void *dst, size_t maxDstSize, const void 
*cSrc, size_t cSrcSize, const HUF_DTable *DTable);
+
+#endif /* HUF_H_298734234 */
diff --git a/grub-core/lib/zstd/huf_decompress.c 
b/grub-core/lib/zstd/huf_decompress.c
new file mode 100644
index 000000000..652648204
--- /dev/null
+++ b/grub-core/lib/zstd/huf_decompress.c
@@ -0,0 +1,960 @@
+/*
+ * Huffman decoder, part of New Generation Entropy library
+ * Copyright (C) 2013-2016, Yann Collet.
+ *
+ * BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *   * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * This program is free software; you can redistribute it and/or modify it 
under
+ * the terms of the GNU General Public License version 2 as published by the
+ * Free Software Foundation. This program is dual-licensed; you may select
+ * either version 2 of the GNU General Public License ("GPL") or BSD license
+ * ("BSD").
+ *
+ * You can contact the author at :
+ * - Source repository : https://github.com/Cyan4973/FiniteStateEntropy
+ */
+
+/* **************************************************************
+*  Compiler specifics
+****************************************************************/
+#define FORCE_INLINE static __always_inline
+
+/* **************************************************************
+*  Dependencies
+****************************************************************/
+#include "bitstream.h" /* BIT_* */
+#include "fse.h"       /* header compression */
+#include "huf.h"
+#include <linux/compiler.h>
+#include <linux/kernel.h>
+#include <linux/string.h> /* memcpy, memset */
+
+/* **************************************************************
+*  Error Management
+****************************************************************/
+#define HUF_STATIC_ASSERT(c)                                   \
+       {                                                      \
+               enum { HUF_static_assert = 1 / (int)(!!(c)) }; \
+       } /* use only *after* variable declarations */
+
+/*-***************************/
+/*  generic DTableDesc       */
+/*-***************************/
+
+typedef struct {
+       BYTE maxTableLog;
+       BYTE tableType;
+       BYTE tableLog;
+       BYTE reserved;
+} DTableDesc;
+
+static DTableDesc HUF_getDTableDesc(const HUF_DTable *table)
+{
+       DTableDesc dtd;
+       memcpy(&dtd, table, sizeof(dtd));
+       return dtd;
+}
+
+/*-***************************/
+/*  single-symbol decoding   */
+/*-***************************/
+
+typedef struct {
+       BYTE byte;
+       BYTE nbBits;
+} HUF_DEltX2; /* single-symbol decoding */
+
+size_t HUF_readDTableX2_wksp(HUF_DTable *DTable, const void *src, size_t 
srcSize, void *workspace, size_t workspaceSize)
+{
+       U32 tableLog = 0;
+       U32 nbSymbols = 0;
+       size_t iSize;
+       void *const dtPtr = DTable + 1;
+       HUF_DEltX2 *const dt = (HUF_DEltX2 *)dtPtr;
+
+       U32 *rankVal;
+       BYTE *huffWeight;
+       size_t spaceUsed32 = 0;
+
+       rankVal = (U32 *)workspace + spaceUsed32;
+       spaceUsed32 += HUF_TABLELOG_ABSOLUTEMAX + 1;
+       huffWeight = (BYTE *)((U32 *)workspace + spaceUsed32);
+       spaceUsed32 += ALIGN(HUF_SYMBOLVALUE_MAX + 1, sizeof(U32)) >> 2;
+
+       if ((spaceUsed32 << 2) > workspaceSize)
+               return ERROR(tableLog_tooLarge);
+       workspace = (U32 *)workspace + spaceUsed32;
+       workspaceSize -= (spaceUsed32 << 2);
+
+       HUF_STATIC_ASSERT(sizeof(DTableDesc) == sizeof(HUF_DTable));
+       /* memset(huffWeight, 0, sizeof(huffWeight)); */ /* is not necessary, 
even though some analyzer complain ... */
+
+       iSize = HUF_readStats_wksp(huffWeight, HUF_SYMBOLVALUE_MAX + 1, 
rankVal, &nbSymbols, &tableLog, src, srcSize, workspace, workspaceSize);
+       if (HUF_isError(iSize))
+               return iSize;
+
+       /* Table header */
+       {
+               DTableDesc dtd = HUF_getDTableDesc(DTable);
+               if (tableLog > (U32)(dtd.maxTableLog + 1))
+                       return ERROR(tableLog_tooLarge); /* DTable too small, 
Huffman tree cannot fit in */
+               dtd.tableType = 0;
+               dtd.tableLog = (BYTE)tableLog;
+               memcpy(DTable, &dtd, sizeof(dtd));
+       }
+
+       /* Calculate starting value for each rank */
+       {
+               U32 n, nextRankStart = 0;
+               for (n = 1; n < tableLog + 1; n++) {
+                       U32 const curr = nextRankStart;
+                       nextRankStart += (rankVal[n] << (n - 1));
+                       rankVal[n] = curr;
+               }
+       }
+
+       /* fill DTable */
+       {
+               U32 n;
+               for (n = 0; n < nbSymbols; n++) {
+                       U32 const w = huffWeight[n];
+                       U32 const length = (1 << w) >> 1;
+                       U32 u;
+                       HUF_DEltX2 D;
+                       D.byte = (BYTE)n;
+                       D.nbBits = (BYTE)(tableLog + 1 - w);
+                       for (u = rankVal[w]; u < rankVal[w] + length; u++)
+                               dt[u] = D;
+                       rankVal[w] += length;
+               }
+       }
+
+       return iSize;
+}
+
+static BYTE HUF_decodeSymbolX2(BIT_DStream_t *Dstream, const HUF_DEltX2 *dt, 
const U32 dtLog)
+{
+       size_t const val = BIT_lookBitsFast(Dstream, dtLog); /* note : dtLog >= 
1 */
+       BYTE const c = dt[val].byte;
+       BIT_skipBits(Dstream, dt[val].nbBits);
+       return c;
+}
+
+#define HUF_DECODE_SYMBOLX2_0(ptr, DStreamPtr) *ptr++ = 
HUF_decodeSymbolX2(DStreamPtr, dt, dtLog)
+
+#define HUF_DECODE_SYMBOLX2_1(ptr, DStreamPtr)         \
+       if (ZSTD_64bits() || (HUF_TABLELOG_MAX <= 12)) \
+       HUF_DECODE_SYMBOLX2_0(ptr, DStreamPtr)
+
+#define HUF_DECODE_SYMBOLX2_2(ptr, DStreamPtr) \
+       if (ZSTD_64bits())                     \
+       HUF_DECODE_SYMBOLX2_0(ptr, DStreamPtr)
+
+FORCE_INLINE size_t HUF_decodeStreamX2(BYTE *p, BIT_DStream_t *const bitDPtr, 
BYTE *const pEnd, const HUF_DEltX2 *const dt, const U32 dtLog)
+{
+       BYTE *const pStart = p;
+
+       /* up to 4 symbols at a time */
+       while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) && (p <= 
pEnd - 4)) {
+               HUF_DECODE_SYMBOLX2_2(p, bitDPtr);
+               HUF_DECODE_SYMBOLX2_1(p, bitDPtr);
+               HUF_DECODE_SYMBOLX2_2(p, bitDPtr);
+               HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
+       }
+
+       /* closer to the end */
+       while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) && (p < 
pEnd))
+               HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
+
+       /* no more data to retrieve from bitstream, hence no need to reload */
+       while (p < pEnd)
+               HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
+
+       return pEnd - pStart;
+}
+
+static size_t HUF_decompress1X2_usingDTable_internal(void *dst, size_t 
dstSize, const void *cSrc, size_t cSrcSize, const HUF_DTable *DTable)
+{
+       BYTE *op = (BYTE *)dst;
+       BYTE *const oend = op + dstSize;
+       const void *dtPtr = DTable + 1;
+       const HUF_DEltX2 *const dt = (const HUF_DEltX2 *)dtPtr;
+       BIT_DStream_t bitD;
+       DTableDesc const dtd = HUF_getDTableDesc(DTable);
+       U32 const dtLog = dtd.tableLog;
+
+       {
+               size_t const errorCode = BIT_initDStream(&bitD, cSrc, cSrcSize);
+               if (HUF_isError(errorCode))
+                       return errorCode;
+       }
+
+       HUF_decodeStreamX2(op, &bitD, oend, dt, dtLog);
+
+       /* check */
+       if (!BIT_endOfDStream(&bitD))
+               return ERROR(corruption_detected);
+
+       return dstSize;
+}
+
+size_t HUF_decompress1X2_usingDTable(void *dst, size_t dstSize, const void 
*cSrc, size_t cSrcSize, const HUF_DTable *DTable)
+{
+       DTableDesc dtd = HUF_getDTableDesc(DTable);
+       if (dtd.tableType != 0)
+               return ERROR(GENERIC);
+       return HUF_decompress1X2_usingDTable_internal(dst, dstSize, cSrc, 
cSrcSize, DTable);
+}
+
+size_t HUF_decompress1X2_DCtx_wksp(HUF_DTable *DCtx, void *dst, size_t 
dstSize, const void *cSrc, size_t cSrcSize, void *workspace, size_t 
workspaceSize)
+{
+       const BYTE *ip = (const BYTE *)cSrc;
+
+       size_t const hSize = HUF_readDTableX2_wksp(DCtx, cSrc, cSrcSize, 
workspace, workspaceSize);
+       if (HUF_isError(hSize))
+               return hSize;
+       if (hSize >= cSrcSize)
+               return ERROR(srcSize_wrong);
+       ip += hSize;
+       cSrcSize -= hSize;
+
+       return HUF_decompress1X2_usingDTable_internal(dst, dstSize, ip, 
cSrcSize, DCtx);
+}
+
+static size_t HUF_decompress4X2_usingDTable_internal(void *dst, size_t 
dstSize, const void *cSrc, size_t cSrcSize, const HUF_DTable *DTable)
+{
+       /* Check */
+       if (cSrcSize < 10)
+               return ERROR(corruption_detected); /* strict minimum : jump 
table + 1 byte per stream */
+
+       {
+               const BYTE *const istart = (const BYTE *)cSrc;
+               BYTE *const ostart = (BYTE *)dst;
+               BYTE *const oend = ostart + dstSize;
+               const void *const dtPtr = DTable + 1;
+               const HUF_DEltX2 *const dt = (const HUF_DEltX2 *)dtPtr;
+
+               /* Init */
+               BIT_DStream_t bitD1;
+               BIT_DStream_t bitD2;
+               BIT_DStream_t bitD3;
+               BIT_DStream_t bitD4;
+               size_t const length1 = ZSTD_readLE16(istart);
+               size_t const length2 = ZSTD_readLE16(istart + 2);
+               size_t const length3 = ZSTD_readLE16(istart + 4);
+               size_t const length4 = cSrcSize - (length1 + length2 + length3 
+ 6);
+               const BYTE *const istart1 = istart + 6; /* jumpTable */
+               const BYTE *const istart2 = istart1 + length1;
+               const BYTE *const istart3 = istart2 + length2;
+               const BYTE *const istart4 = istart3 + length3;
+               const size_t segmentSize = (dstSize + 3) / 4;
+               BYTE *const opStart2 = ostart + segmentSize;
+               BYTE *const opStart3 = opStart2 + segmentSize;
+               BYTE *const opStart4 = opStart3 + segmentSize;
+               BYTE *op1 = ostart;
+               BYTE *op2 = opStart2;
+               BYTE *op3 = opStart3;
+               BYTE *op4 = opStart4;
+               U32 endSignal;
+               DTableDesc const dtd = HUF_getDTableDesc(DTable);
+               U32 const dtLog = dtd.tableLog;
+
+               if (length4 > cSrcSize)
+                       return ERROR(corruption_detected); /* overflow */
+               {
+                       size_t const errorCode = BIT_initDStream(&bitD1, 
istart1, length1);
+                       if (HUF_isError(errorCode))
+                               return errorCode;
+               }
+               {
+                       size_t const errorCode = BIT_initDStream(&bitD2, 
istart2, length2);
+                       if (HUF_isError(errorCode))
+                               return errorCode;
+               }
+               {
+                       size_t const errorCode = BIT_initDStream(&bitD3, 
istart3, length3);
+                       if (HUF_isError(errorCode))
+                               return errorCode;
+               }
+               {
+                       size_t const errorCode = BIT_initDStream(&bitD4, 
istart4, length4);
+                       if (HUF_isError(errorCode))
+                               return errorCode;
+               }
+
+               /* 16-32 symbols per loop (4-8 symbols per stream) */
+               endSignal = BIT_reloadDStream(&bitD1) | 
BIT_reloadDStream(&bitD2) | BIT_reloadDStream(&bitD3) | 
BIT_reloadDStream(&bitD4);
+               for (; (endSignal == BIT_DStream_unfinished) && (op4 < (oend - 
7));) {
+                       HUF_DECODE_SYMBOLX2_2(op1, &bitD1);
+                       HUF_DECODE_SYMBOLX2_2(op2, &bitD2);
+                       HUF_DECODE_SYMBOLX2_2(op3, &bitD3);
+                       HUF_DECODE_SYMBOLX2_2(op4, &bitD4);
+                       HUF_DECODE_SYMBOLX2_1(op1, &bitD1);
+                       HUF_DECODE_SYMBOLX2_1(op2, &bitD2);
+                       HUF_DECODE_SYMBOLX2_1(op3, &bitD3);
+                       HUF_DECODE_SYMBOLX2_1(op4, &bitD4);
+                       HUF_DECODE_SYMBOLX2_2(op1, &bitD1);
+                       HUF_DECODE_SYMBOLX2_2(op2, &bitD2);
+                       HUF_DECODE_SYMBOLX2_2(op3, &bitD3);
+                       HUF_DECODE_SYMBOLX2_2(op4, &bitD4);
+                       HUF_DECODE_SYMBOLX2_0(op1, &bitD1);
+                       HUF_DECODE_SYMBOLX2_0(op2, &bitD2);
+                       HUF_DECODE_SYMBOLX2_0(op3, &bitD3);
+                       HUF_DECODE_SYMBOLX2_0(op4, &bitD4);
+                       endSignal = BIT_reloadDStream(&bitD1) | 
BIT_reloadDStream(&bitD2) | BIT_reloadDStream(&bitD3) | 
BIT_reloadDStream(&bitD4);
+               }
+
+               /* check corruption */
+               if (op1 > opStart2)
+                       return ERROR(corruption_detected);
+               if (op2 > opStart3)
+                       return ERROR(corruption_detected);
+               if (op3 > opStart4)
+                       return ERROR(corruption_detected);
+               /* note : op4 supposed already verified within main loop */
+
+               /* finish bitStreams one by one */
+               HUF_decodeStreamX2(op1, &bitD1, opStart2, dt, dtLog);
+               HUF_decodeStreamX2(op2, &bitD2, opStart3, dt, dtLog);
+               HUF_decodeStreamX2(op3, &bitD3, opStart4, dt, dtLog);
+               HUF_decodeStreamX2(op4, &bitD4, oend, dt, dtLog);
+
+               /* check */
+               endSignal = BIT_endOfDStream(&bitD1) & BIT_endOfDStream(&bitD2) 
& BIT_endOfDStream(&bitD3) & BIT_endOfDStream(&bitD4);
+               if (!endSignal)
+                       return ERROR(corruption_detected);
+
+               /* decoded size */
+               return dstSize;
+       }
+}
+
+size_t HUF_decompress4X2_usingDTable(void *dst, size_t dstSize, const void 
*cSrc, size_t cSrcSize, const HUF_DTable *DTable)
+{
+       DTableDesc dtd = HUF_getDTableDesc(DTable);
+       if (dtd.tableType != 0)
+               return ERROR(GENERIC);
+       return HUF_decompress4X2_usingDTable_internal(dst, dstSize, cSrc, 
cSrcSize, DTable);
+}
+
+size_t HUF_decompress4X2_DCtx_wksp(HUF_DTable *dctx, void *dst, size_t 
dstSize, const void *cSrc, size_t cSrcSize, void *workspace, size_t 
workspaceSize)
+{
+       const BYTE *ip = (const BYTE *)cSrc;
+
+       size_t const hSize = HUF_readDTableX2_wksp(dctx, cSrc, cSrcSize, 
workspace, workspaceSize);
+       if (HUF_isError(hSize))
+               return hSize;
+       if (hSize >= cSrcSize)
+               return ERROR(srcSize_wrong);
+       ip += hSize;
+       cSrcSize -= hSize;
+
+       return HUF_decompress4X2_usingDTable_internal(dst, dstSize, ip, 
cSrcSize, dctx);
+}
+
+/* *************************/
+/* double-symbols decoding */
+/* *************************/
+typedef struct {
+       U16 sequence;
+       BYTE nbBits;
+       BYTE length;
+} HUF_DEltX4; /* double-symbols decoding */
+
+typedef struct {
+       BYTE symbol;
+       BYTE weight;
+} sortedSymbol_t;
+
+/* HUF_fillDTableX4Level2() :
+ * `rankValOrigin` must be a table of at least (HUF_TABLELOG_MAX + 1) U32 */
+static void HUF_fillDTableX4Level2(HUF_DEltX4 *DTable, U32 sizeLog, const U32 
consumed, const U32 *rankValOrigin, const int minWeight,
+                                  const sortedSymbol_t *sortedSymbols, const 
U32 sortedListSize, U32 nbBitsBaseline, U16 baseSeq)
+{
+       HUF_DEltX4 DElt;
+       U32 rankVal[HUF_TABLELOG_MAX + 1];
+
+       /* get pre-calculated rankVal */
+       memcpy(rankVal, rankValOrigin, sizeof(rankVal));
+
+       /* fill skipped values */
+       if (minWeight > 1) {
+               U32 i, skipSize = rankVal[minWeight];
+               ZSTD_writeLE16(&(DElt.sequence), baseSeq);
+               DElt.nbBits = (BYTE)(consumed);
+               DElt.length = 1;
+               for (i = 0; i < skipSize; i++)
+                       DTable[i] = DElt;
+       }
+
+       /* fill DTable */
+       {
+               U32 s;
+               for (s = 0; s < sortedListSize; s++) { /* note : sortedSymbols 
already skipped */
+                       const U32 symbol = sortedSymbols[s].symbol;
+                       const U32 weight = sortedSymbols[s].weight;
+                       const U32 nbBits = nbBitsBaseline - weight;
+                       const U32 length = 1 << (sizeLog - nbBits);
+                       const U32 start = rankVal[weight];
+                       U32 i = start;
+                       const U32 end = start + length;
+
+                       ZSTD_writeLE16(&(DElt.sequence), (U16)(baseSeq + 
(symbol << 8)));
+                       DElt.nbBits = (BYTE)(nbBits + consumed);
+                       DElt.length = 2;
+                       do {
+                               DTable[i++] = DElt;
+                       } while (i < end); /* since length >= 1 */
+
+                       rankVal[weight] += length;
+               }
+       }
+}
+
+typedef U32 rankVal_t[HUF_TABLELOG_MAX][HUF_TABLELOG_MAX + 1];
+typedef U32 rankValCol_t[HUF_TABLELOG_MAX + 1];
+
+static void HUF_fillDTableX4(HUF_DEltX4 *DTable, const U32 targetLog, const 
sortedSymbol_t *sortedList, const U32 sortedListSize, const U32 *rankStart,
+                            rankVal_t rankValOrigin, const U32 maxWeight, 
const U32 nbBitsBaseline)
+{
+       U32 rankVal[HUF_TABLELOG_MAX + 1];
+       const int scaleLog = nbBitsBaseline - targetLog; /* note : targetLog >= 
srcLog, hence scaleLog <= 1 */
+       const U32 minBits = nbBitsBaseline - maxWeight;
+       U32 s;
+
+       memcpy(rankVal, rankValOrigin, sizeof(rankVal));
+
+       /* fill DTable */
+       for (s = 0; s < sortedListSize; s++) {
+               const U16 symbol = sortedList[s].symbol;
+               const U32 weight = sortedList[s].weight;
+               const U32 nbBits = nbBitsBaseline - weight;
+               const U32 start = rankVal[weight];
+               const U32 length = 1 << (targetLog - nbBits);
+
+               if (targetLog - nbBits >= minBits) { /* enough room for a 
second symbol */
+                       U32 sortedRank;
+                       int minWeight = nbBits + scaleLog;
+                       if (minWeight < 1)
+                               minWeight = 1;
+                       sortedRank = rankStart[minWeight];
+                       HUF_fillDTableX4Level2(DTable + start, targetLog - 
nbBits, nbBits, rankValOrigin[nbBits], minWeight, sortedList + sortedRank,
+                                              sortedListSize - sortedRank, 
nbBitsBaseline, symbol);
+               } else {
+                       HUF_DEltX4 DElt;
+                       ZSTD_writeLE16(&(DElt.sequence), symbol);
+                       DElt.nbBits = (BYTE)(nbBits);
+                       DElt.length = 1;
+                       {
+                               U32 const end = start + length;
+                               U32 u;
+                               for (u = start; u < end; u++)
+                                       DTable[u] = DElt;
+                       }
+               }
+               rankVal[weight] += length;
+       }
+}
+
+size_t HUF_readDTableX4_wksp(HUF_DTable *DTable, const void *src, size_t 
srcSize, void *workspace, size_t workspaceSize)
+{
+       U32 tableLog, maxW, sizeOfSort, nbSymbols;
+       DTableDesc dtd = HUF_getDTableDesc(DTable);
+       U32 const maxTableLog = dtd.maxTableLog;
+       size_t iSize;
+       void *dtPtr = DTable + 1; /* force compiler to avoid strict-aliasing */
+       HUF_DEltX4 *const dt = (HUF_DEltX4 *)dtPtr;
+       U32 *rankStart;
+
+       rankValCol_t *rankVal;
+       U32 *rankStats;
+       U32 *rankStart0;
+       sortedSymbol_t *sortedSymbol;
+       BYTE *weightList;
+       size_t spaceUsed32 = 0;
+
+       HUF_STATIC_ASSERT((sizeof(rankValCol_t) & 3) == 0);
+
+       rankVal = (rankValCol_t *)((U32 *)workspace + spaceUsed32);
+       spaceUsed32 += (sizeof(rankValCol_t) * HUF_TABLELOG_MAX) >> 2;
+       rankStats = (U32 *)workspace + spaceUsed32;
+       spaceUsed32 += HUF_TABLELOG_MAX + 1;
+       rankStart0 = (U32 *)workspace + spaceUsed32;
+       spaceUsed32 += HUF_TABLELOG_MAX + 2;
+       sortedSymbol = (sortedSymbol_t *)((U32 *)workspace + spaceUsed32);
+       spaceUsed32 += ALIGN(sizeof(sortedSymbol_t) * (HUF_SYMBOLVALUE_MAX + 
1), sizeof(U32)) >> 2;
+       weightList = (BYTE *)((U32 *)workspace + spaceUsed32);
+       spaceUsed32 += ALIGN(HUF_SYMBOLVALUE_MAX + 1, sizeof(U32)) >> 2;
+
+       if ((spaceUsed32 << 2) > workspaceSize)
+               return ERROR(tableLog_tooLarge);
+       workspace = (U32 *)workspace + spaceUsed32;
+       workspaceSize -= (spaceUsed32 << 2);
+
+       rankStart = rankStart0 + 1;
+       memset(rankStats, 0, sizeof(U32) * (2 * HUF_TABLELOG_MAX + 2 + 1));
+
+       HUF_STATIC_ASSERT(sizeof(HUF_DEltX4) == sizeof(HUF_DTable)); /* if 
compiler fails here, assertion is wrong */
+       if (maxTableLog > HUF_TABLELOG_MAX)
+               return ERROR(tableLog_tooLarge);
+       /* memset(weightList, 0, sizeof(weightList)); */ /* is not necessary, 
even though some analyzer complain ... */
+
+       iSize = HUF_readStats_wksp(weightList, HUF_SYMBOLVALUE_MAX + 1, 
rankStats, &nbSymbols, &tableLog, src, srcSize, workspace, workspaceSize);
+       if (HUF_isError(iSize))
+               return iSize;
+
+       /* check result */
+       if (tableLog > maxTableLog)
+               return ERROR(tableLog_tooLarge); /* DTable can't fit code depth 
*/
+
+       /* find maxWeight */
+       for (maxW = tableLog; rankStats[maxW] == 0; maxW--) {
+       } /* necessarily finds a solution before 0 */
+
+       /* Get start index of each weight */
+       {
+               U32 w, nextRankStart = 0;
+               for (w = 1; w < maxW + 1; w++) {
+                       U32 curr = nextRankStart;
+                       nextRankStart += rankStats[w];
+                       rankStart[w] = curr;
+               }
+               rankStart[0] = nextRankStart; /* put all 0w symbols at the end 
of sorted list*/
+               sizeOfSort = nextRankStart;
+       }
+
+       /* sort symbols by weight */
+       {
+               U32 s;
+               for (s = 0; s < nbSymbols; s++) {
+                       U32 const w = weightList[s];
+                       U32 const r = rankStart[w]++;
+                       sortedSymbol[r].symbol = (BYTE)s;
+                       sortedSymbol[r].weight = (BYTE)w;
+               }
+               rankStart[0] = 0; /* forget 0w symbols; this is beginning of 
weight(1) */
+       }
+
+       /* Build rankVal */
+       {
+               U32 *const rankVal0 = rankVal[0];
+               {
+                       int const rescale = (maxTableLog - tableLog) - 1; /* 
tableLog <= maxTableLog */
+                       U32 nextRankVal = 0;
+                       U32 w;
+                       for (w = 1; w < maxW + 1; w++) {
+                               U32 curr = nextRankVal;
+                               nextRankVal += rankStats[w] << (w + rescale);
+                               rankVal0[w] = curr;
+                       }
+               }
+               {
+                       U32 const minBits = tableLog + 1 - maxW;
+                       U32 consumed;
+                       for (consumed = minBits; consumed < maxTableLog - 
minBits + 1; consumed++) {
+                               U32 *const rankValPtr = rankVal[consumed];
+                               U32 w;
+                               for (w = 1; w < maxW + 1; w++) {
+                                       rankValPtr[w] = rankVal0[w] >> consumed;
+                               }
+                       }
+               }
+       }
+
+       HUF_fillDTableX4(dt, maxTableLog, sortedSymbol, sizeOfSort, rankStart0, 
rankVal, maxW, tableLog + 1);
+
+       dtd.tableLog = (BYTE)maxTableLog;
+       dtd.tableType = 1;
+       memcpy(DTable, &dtd, sizeof(dtd));
+       return iSize;
+}
+
+static U32 HUF_decodeSymbolX4(void *op, BIT_DStream_t *DStream, const 
HUF_DEltX4 *dt, const U32 dtLog)
+{
+       size_t const val = BIT_lookBitsFast(DStream, dtLog); /* note : dtLog >= 
1 */
+       memcpy(op, dt + val, 2);
+       BIT_skipBits(DStream, dt[val].nbBits);
+       return dt[val].length;
+}
+
+static U32 HUF_decodeLastSymbolX4(void *op, BIT_DStream_t *DStream, const 
HUF_DEltX4 *dt, const U32 dtLog)
+{
+       size_t const val = BIT_lookBitsFast(DStream, dtLog); /* note : dtLog >= 
1 */
+       memcpy(op, dt + val, 1);
+       if (dt[val].length == 1)
+               BIT_skipBits(DStream, dt[val].nbBits);
+       else {
+               if (DStream->bitsConsumed < (sizeof(DStream->bitContainer) * 
8)) {
+                       BIT_skipBits(DStream, dt[val].nbBits);
+                       if (DStream->bitsConsumed > 
(sizeof(DStream->bitContainer) * 8))
+                               /* ugly hack; works only because it's the last 
symbol. Note : can't easily extract nbBits from just this symbol */
+                               DStream->bitsConsumed = 
(sizeof(DStream->bitContainer) * 8);
+               }
+       }
+       return 1;
+}
+
+#define HUF_DECODE_SYMBOLX4_0(ptr, DStreamPtr) ptr += HUF_decodeSymbolX4(ptr, 
DStreamPtr, dt, dtLog)
+
+#define HUF_DECODE_SYMBOLX4_1(ptr, DStreamPtr)         \
+       if (ZSTD_64bits() || (HUF_TABLELOG_MAX <= 12)) \
+       ptr += HUF_decodeSymbolX4(ptr, DStreamPtr, dt, dtLog)
+
+#define HUF_DECODE_SYMBOLX4_2(ptr, DStreamPtr) \
+       if (ZSTD_64bits())                     \
+       ptr += HUF_decodeSymbolX4(ptr, DStreamPtr, dt, dtLog)
+
+FORCE_INLINE size_t HUF_decodeStreamX4(BYTE *p, BIT_DStream_t *bitDPtr, BYTE 
*const pEnd, const HUF_DEltX4 *const dt, const U32 dtLog)
+{
+       BYTE *const pStart = p;
+
+       /* up to 8 symbols at a time */
+       while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) & (p < 
pEnd - (sizeof(bitDPtr->bitContainer) - 1))) {
+               HUF_DECODE_SYMBOLX4_2(p, bitDPtr);
+               HUF_DECODE_SYMBOLX4_1(p, bitDPtr);
+               HUF_DECODE_SYMBOLX4_2(p, bitDPtr);
+               HUF_DECODE_SYMBOLX4_0(p, bitDPtr);
+       }
+
+       /* closer to end : up to 2 symbols at a time */
+       while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) & (p <= 
pEnd - 2))
+               HUF_DECODE_SYMBOLX4_0(p, bitDPtr);
+
+       while (p <= pEnd - 2)
+               HUF_DECODE_SYMBOLX4_0(p, bitDPtr); /* no need to reload : 
reached the end of DStream */
+
+       if (p < pEnd)
+               p += HUF_decodeLastSymbolX4(p, bitDPtr, dt, dtLog);
+
+       return p - pStart;
+}
+
+static size_t HUF_decompress1X4_usingDTable_internal(void *dst, size_t 
dstSize, const void *cSrc, size_t cSrcSize, const HUF_DTable *DTable)
+{
+       BIT_DStream_t bitD;
+
+       /* Init */
+       {
+               size_t const errorCode = BIT_initDStream(&bitD, cSrc, cSrcSize);
+               if (HUF_isError(errorCode))
+                       return errorCode;
+       }
+
+       /* decode */
+       {
+               BYTE *const ostart = (BYTE *)dst;
+               BYTE *const oend = ostart + dstSize;
+               const void *const dtPtr = DTable + 1; /* force compiler to not 
use strict-aliasing */
+               const HUF_DEltX4 *const dt = (const HUF_DEltX4 *)dtPtr;
+               DTableDesc const dtd = HUF_getDTableDesc(DTable);
+               HUF_decodeStreamX4(ostart, &bitD, oend, dt, dtd.tableLog);
+       }
+
+       /* check */
+       if (!BIT_endOfDStream(&bitD))
+               return ERROR(corruption_detected);
+
+       /* decoded size */
+       return dstSize;
+}
+
+size_t HUF_decompress1X4_usingDTable(void *dst, size_t dstSize, const void 
*cSrc, size_t cSrcSize, const HUF_DTable *DTable)
+{
+       DTableDesc dtd = HUF_getDTableDesc(DTable);
+       if (dtd.tableType != 1)
+               return ERROR(GENERIC);
+       return HUF_decompress1X4_usingDTable_internal(dst, dstSize, cSrc, 
cSrcSize, DTable);
+}
+
+size_t HUF_decompress1X4_DCtx_wksp(HUF_DTable *DCtx, void *dst, size_t 
dstSize, const void *cSrc, size_t cSrcSize, void *workspace, size_t 
workspaceSize)
+{
+       const BYTE *ip = (const BYTE *)cSrc;
+
+       size_t const hSize = HUF_readDTableX4_wksp(DCtx, cSrc, cSrcSize, 
workspace, workspaceSize);
+       if (HUF_isError(hSize))
+               return hSize;
+       if (hSize >= cSrcSize)
+               return ERROR(srcSize_wrong);
+       ip += hSize;
+       cSrcSize -= hSize;
+
+       return HUF_decompress1X4_usingDTable_internal(dst, dstSize, ip, 
cSrcSize, DCtx);
+}
+
+static size_t HUF_decompress4X4_usingDTable_internal(void *dst, size_t 
dstSize, const void *cSrc, size_t cSrcSize, const HUF_DTable *DTable)
+{
+       if (cSrcSize < 10)
+               return ERROR(corruption_detected); /* strict minimum : jump 
table + 1 byte per stream */
+
+       {
+               const BYTE *const istart = (const BYTE *)cSrc;
+               BYTE *const ostart = (BYTE *)dst;
+               BYTE *const oend = ostart + dstSize;
+               const void *const dtPtr = DTable + 1;
+               const HUF_DEltX4 *const dt = (const HUF_DEltX4 *)dtPtr;
+
+               /* Init */
+               BIT_DStream_t bitD1;
+               BIT_DStream_t bitD2;
+               BIT_DStream_t bitD3;
+               BIT_DStream_t bitD4;
+               size_t const length1 = ZSTD_readLE16(istart);
+               size_t const length2 = ZSTD_readLE16(istart + 2);
+               size_t const length3 = ZSTD_readLE16(istart + 4);
+               size_t const length4 = cSrcSize - (length1 + length2 + length3 
+ 6);
+               const BYTE *const istart1 = istart + 6; /* jumpTable */
+               const BYTE *const istart2 = istart1 + length1;
+               const BYTE *const istart3 = istart2 + length2;
+               const BYTE *const istart4 = istart3 + length3;
+               size_t const segmentSize = (dstSize + 3) / 4;
+               BYTE *const opStart2 = ostart + segmentSize;
+               BYTE *const opStart3 = opStart2 + segmentSize;
+               BYTE *const opStart4 = opStart3 + segmentSize;
+               BYTE *op1 = ostart;
+               BYTE *op2 = opStart2;
+               BYTE *op3 = opStart3;
+               BYTE *op4 = opStart4;
+               U32 endSignal;
+               DTableDesc const dtd = HUF_getDTableDesc(DTable);
+               U32 const dtLog = dtd.tableLog;
+
+               if (length4 > cSrcSize)
+                       return ERROR(corruption_detected); /* overflow */
+               {
+                       size_t const errorCode = BIT_initDStream(&bitD1, 
istart1, length1);
+                       if (HUF_isError(errorCode))
+                               return errorCode;
+               }
+               {
+                       size_t const errorCode = BIT_initDStream(&bitD2, 
istart2, length2);
+                       if (HUF_isError(errorCode))
+                               return errorCode;
+               }
+               {
+                       size_t const errorCode = BIT_initDStream(&bitD3, 
istart3, length3);
+                       if (HUF_isError(errorCode))
+                               return errorCode;
+               }
+               {
+                       size_t const errorCode = BIT_initDStream(&bitD4, 
istart4, length4);
+                       if (HUF_isError(errorCode))
+                               return errorCode;
+               }
+
+               /* 16-32 symbols per loop (4-8 symbols per stream) */
+               endSignal = BIT_reloadDStream(&bitD1) | 
BIT_reloadDStream(&bitD2) | BIT_reloadDStream(&bitD3) | 
BIT_reloadDStream(&bitD4);
+               for (; (endSignal == BIT_DStream_unfinished) & (op4 < (oend - 
(sizeof(bitD4.bitContainer) - 1)));) {
+                       HUF_DECODE_SYMBOLX4_2(op1, &bitD1);
+                       HUF_DECODE_SYMBOLX4_2(op2, &bitD2);
+                       HUF_DECODE_SYMBOLX4_2(op3, &bitD3);
+                       HUF_DECODE_SYMBOLX4_2(op4, &bitD4);
+                       HUF_DECODE_SYMBOLX4_1(op1, &bitD1);
+                       HUF_DECODE_SYMBOLX4_1(op2, &bitD2);
+                       HUF_DECODE_SYMBOLX4_1(op3, &bitD3);
+                       HUF_DECODE_SYMBOLX4_1(op4, &bitD4);
+                       HUF_DECODE_SYMBOLX4_2(op1, &bitD1);
+                       HUF_DECODE_SYMBOLX4_2(op2, &bitD2);
+                       HUF_DECODE_SYMBOLX4_2(op3, &bitD3);
+                       HUF_DECODE_SYMBOLX4_2(op4, &bitD4);
+                       HUF_DECODE_SYMBOLX4_0(op1, &bitD1);
+                       HUF_DECODE_SYMBOLX4_0(op2, &bitD2);
+                       HUF_DECODE_SYMBOLX4_0(op3, &bitD3);
+                       HUF_DECODE_SYMBOLX4_0(op4, &bitD4);
+
+                       endSignal = BIT_reloadDStream(&bitD1) | 
BIT_reloadDStream(&bitD2) | BIT_reloadDStream(&bitD3) | 
BIT_reloadDStream(&bitD4);
+               }
+
+               /* check corruption */
+               if (op1 > opStart2)
+                       return ERROR(corruption_detected);
+               if (op2 > opStart3)
+                       return ERROR(corruption_detected);
+               if (op3 > opStart4)
+                       return ERROR(corruption_detected);
+               /* note : op4 already verified within main loop */
+
+               /* finish bitStreams one by one */
+               HUF_decodeStreamX4(op1, &bitD1, opStart2, dt, dtLog);
+               HUF_decodeStreamX4(op2, &bitD2, opStart3, dt, dtLog);
+               HUF_decodeStreamX4(op3, &bitD3, opStart4, dt, dtLog);
+               HUF_decodeStreamX4(op4, &bitD4, oend, dt, dtLog);
+
+               /* check */
+               {
+                       U32 const endCheck = BIT_endOfDStream(&bitD1) & 
BIT_endOfDStream(&bitD2) & BIT_endOfDStream(&bitD3) & BIT_endOfDStream(&bitD4);
+                       if (!endCheck)
+                               return ERROR(corruption_detected);
+               }
+
+               /* decoded size */
+               return dstSize;
+       }
+}
+
+size_t HUF_decompress4X4_usingDTable(void *dst, size_t dstSize, const void 
*cSrc, size_t cSrcSize, const HUF_DTable *DTable)
+{
+       DTableDesc dtd = HUF_getDTableDesc(DTable);
+       if (dtd.tableType != 1)
+               return ERROR(GENERIC);
+       return HUF_decompress4X4_usingDTable_internal(dst, dstSize, cSrc, 
cSrcSize, DTable);
+}
+
+size_t HUF_decompress4X4_DCtx_wksp(HUF_DTable *dctx, void *dst, size_t 
dstSize, const void *cSrc, size_t cSrcSize, void *workspace, size_t 
workspaceSize)
+{
+       const BYTE *ip = (const BYTE *)cSrc;
+
+       size_t hSize = HUF_readDTableX4_wksp(dctx, cSrc, cSrcSize, workspace, 
workspaceSize);
+       if (HUF_isError(hSize))
+               return hSize;
+       if (hSize >= cSrcSize)
+               return ERROR(srcSize_wrong);
+       ip += hSize;
+       cSrcSize -= hSize;
+
+       return HUF_decompress4X4_usingDTable_internal(dst, dstSize, ip, 
cSrcSize, dctx);
+}
+
+/* ********************************/
+/* Generic decompression selector */
+/* ********************************/
+
+size_t HUF_decompress1X_usingDTable(void *dst, size_t maxDstSize, const void 
*cSrc, size_t cSrcSize, const HUF_DTable *DTable)
+{
+       DTableDesc const dtd = HUF_getDTableDesc(DTable);
+       return dtd.tableType ? HUF_decompress1X4_usingDTable_internal(dst, 
maxDstSize, cSrc, cSrcSize, DTable)
+                            : HUF_decompress1X2_usingDTable_internal(dst, 
maxDstSize, cSrc, cSrcSize, DTable);
+}
+
+size_t HUF_decompress4X_usingDTable(void *dst, size_t maxDstSize, const void 
*cSrc, size_t cSrcSize, const HUF_DTable *DTable)
+{
+       DTableDesc const dtd = HUF_getDTableDesc(DTable);
+       return dtd.tableType ? HUF_decompress4X4_usingDTable_internal(dst, 
maxDstSize, cSrc, cSrcSize, DTable)
+                            : HUF_decompress4X2_usingDTable_internal(dst, 
maxDstSize, cSrc, cSrcSize, DTable);
+}
+
+typedef struct {
+       U32 tableTime;
+       U32 decode256Time;
+} algo_time_t;
+static const algo_time_t algoTime[16 /* Quantization */][3 /* single, double, 
quad */] = {
+    /* single, double, quad */
+    {{0, 0}, {1, 1}, {2, 2}},               /* Q==0 : impossible */
+    {{0, 0}, {1, 1}, {2, 2}},               /* Q==1 : impossible */
+    {{38, 130}, {1313, 74}, {2151, 38}},     /* Q == 2 : 12-18% */
+    {{448, 128}, {1353, 74}, {2238, 41}},    /* Q == 3 : 18-25% */
+    {{556, 128}, {1353, 74}, {2238, 47}},    /* Q == 4 : 25-32% */
+    {{714, 128}, {1418, 74}, {2436, 53}},    /* Q == 5 : 32-38% */
+    {{883, 128}, {1437, 74}, {2464, 61}},    /* Q == 6 : 38-44% */
+    {{897, 128}, {1515, 75}, {2622, 68}},    /* Q == 7 : 44-50% */
+    {{926, 128}, {1613, 75}, {2730, 75}},    /* Q == 8 : 50-56% */
+    {{947, 128}, {1729, 77}, {3359, 77}},    /* Q == 9 : 56-62% */
+    {{1107, 128}, {2083, 81}, {4006, 84}},   /* Q ==10 : 62-69% */
+    {{1177, 128}, {2379, 87}, {4785, 88}},   /* Q ==11 : 69-75% */
+    {{1242, 128}, {2415, 93}, {5155, 84}},   /* Q ==12 : 75-81% */
+    {{1349, 128}, {2644, 106}, {5260, 106}}, /* Q ==13 : 81-87% */
+    {{1455, 128}, {2422, 124}, {4174, 124}}, /* Q ==14 : 87-93% */
+    {{722, 128}, {1891, 145}, {1936, 146}},  /* Q ==15 : 93-99% */
+};
+
+/** HUF_selectDecoder() :
+*   Tells which decoder is likely to decode faster,
+*   based on a set of pre-determined metrics.
+*   @return : 0==HUF_decompress4X2, 1==HUF_decompress4X4 .
+*   Assumption : 0 < cSrcSize < dstSize <= 128 KB */
+U32 HUF_selectDecoder(size_t dstSize, size_t cSrcSize)
+{
+       /* decoder timing evaluation */
+       U32 const Q = (U32)(cSrcSize * 16 / dstSize); /* Q < 16 since dstSize > 
cSrcSize */
+       U32 const D256 = (U32)(dstSize >> 8);
+       U32 const DTime0 = algoTime[Q][0].tableTime + 
(algoTime[Q][0].decode256Time * D256);
+       U32 DTime1 = algoTime[Q][1].tableTime + (algoTime[Q][1].decode256Time * 
D256);
+       DTime1 += DTime1 >> 3; /* advantage to algorithm using less memory, for 
cache eviction */
+
+       return DTime1 < DTime0;
+}
+
+typedef size_t (*decompressionAlgo)(void *dst, size_t dstSize, const void 
*cSrc, size_t cSrcSize);
+
+size_t HUF_decompress4X_DCtx_wksp(HUF_DTable *dctx, void *dst, size_t dstSize, 
const void *cSrc, size_t cSrcSize, void *workspace, size_t workspaceSize)
+{
+       /* validation checks */
+       if (dstSize == 0)
+               return ERROR(dstSize_tooSmall);
+       if (cSrcSize > dstSize)
+               return ERROR(corruption_detected); /* invalid */
+       if (cSrcSize == dstSize) {
+               memcpy(dst, cSrc, dstSize);
+               return dstSize;
+       } /* not compressed */
+       if (cSrcSize == 1) {
+               memset(dst, *(const BYTE *)cSrc, dstSize);
+               return dstSize;
+       } /* RLE */
+
+       {
+               U32 const algoNb = HUF_selectDecoder(dstSize, cSrcSize);
+               return algoNb ? HUF_decompress4X4_DCtx_wksp(dctx, dst, dstSize, 
cSrc, cSrcSize, workspace, workspaceSize)
+                             : HUF_decompress4X2_DCtx_wksp(dctx, dst, dstSize, 
cSrc, cSrcSize, workspace, workspaceSize);
+       }
+}
+
+size_t HUF_decompress4X_hufOnly_wksp(HUF_DTable *dctx, void *dst, size_t 
dstSize, const void *cSrc, size_t cSrcSize, void *workspace, size_t 
workspaceSize)
+{
+       /* validation checks */
+       if (dstSize == 0)
+               return ERROR(dstSize_tooSmall);
+       if ((cSrcSize >= dstSize) || (cSrcSize <= 1))
+               return ERROR(corruption_detected); /* invalid */
+
+       {
+               U32 const algoNb = HUF_selectDecoder(dstSize, cSrcSize);
+               return algoNb ? HUF_decompress4X4_DCtx_wksp(dctx, dst, dstSize, 
cSrc, cSrcSize, workspace, workspaceSize)
+                             : HUF_decompress4X2_DCtx_wksp(dctx, dst, dstSize, 
cSrc, cSrcSize, workspace, workspaceSize);
+       }
+}
+
+size_t HUF_decompress1X_DCtx_wksp(HUF_DTable *dctx, void *dst, size_t dstSize, 
const void *cSrc, size_t cSrcSize, void *workspace, size_t workspaceSize)
+{
+       /* validation checks */
+       if (dstSize == 0)
+               return ERROR(dstSize_tooSmall);
+       if (cSrcSize > dstSize)
+               return ERROR(corruption_detected); /* invalid */
+       if (cSrcSize == dstSize) {
+               memcpy(dst, cSrc, dstSize);
+               return dstSize;
+       } /* not compressed */
+       if (cSrcSize == 1) {
+               memset(dst, *(const BYTE *)cSrc, dstSize);
+               return dstSize;
+       } /* RLE */
+
+       {
+               U32 const algoNb = HUF_selectDecoder(dstSize, cSrcSize);
+               return algoNb ? HUF_decompress1X4_DCtx_wksp(dctx, dst, dstSize, 
cSrc, cSrcSize, workspace, workspaceSize)
+                             : HUF_decompress1X2_DCtx_wksp(dctx, dst, dstSize, 
cSrc, cSrcSize, workspace, workspaceSize);
+       }
+}
diff --git a/grub-core/lib/zstd/mem.h b/grub-core/lib/zstd/mem.h
new file mode 100644
index 000000000..3a0f34c87
--- /dev/null
+++ b/grub-core/lib/zstd/mem.h
@@ -0,0 +1,151 @@
+/**
+ * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of https://github.com/facebook/zstd.
+ * An additional grant of patent rights can be found in the PATENTS file in the
+ * same directory.
+ *
+ * This program is free software; you can redistribute it and/or modify it 
under
+ * the terms of the GNU General Public License version 2 as published by the
+ * Free Software Foundation. This program is dual-licensed; you may select
+ * either version 2 of the GNU General Public License ("GPL") or BSD license
+ * ("BSD").
+ */
+
+#ifndef MEM_H_MODULE
+#define MEM_H_MODULE
+
+/*-****************************************
+*  Dependencies
+******************************************/
+#include <asm/unaligned.h>
+#include <linux/string.h> /* memcpy */
+#include <linux/types.h>  /* size_t, ptrdiff_t */
+
+/*-****************************************
+*  Compiler specifics
+******************************************/
+#define ZSTD_STATIC static __inline __attribute__((unused))
+
+/*-**************************************************************
+*  Basic Types
+*****************************************************************/
+typedef uint8_t BYTE;
+typedef uint16_t U16;
+typedef int16_t S16;
+typedef uint32_t U32;
+typedef int32_t S32;
+typedef uint64_t U64;
+typedef int64_t S64;
+typedef ptrdiff_t iPtrDiff;
+typedef uintptr_t uPtrDiff;
+
+/*-**************************************************************
+*  Memory I/O
+*****************************************************************/
+ZSTD_STATIC unsigned ZSTD_32bits(void) { return sizeof(size_t) == 4; }
+ZSTD_STATIC unsigned ZSTD_64bits(void) { return sizeof(size_t) == 8; }
+
+#if defined(__LITTLE_ENDIAN)
+#define ZSTD_LITTLE_ENDIAN 1
+#else
+#define ZSTD_LITTLE_ENDIAN 0
+#endif
+
+ZSTD_STATIC unsigned ZSTD_isLittleEndian(void) { return ZSTD_LITTLE_ENDIAN; }
+
+ZSTD_STATIC U16 ZSTD_read16(const void *memPtr) { return get_unaligned((const 
U16 *)memPtr); }
+
+ZSTD_STATIC U32 ZSTD_read32(const void *memPtr) { return get_unaligned((const 
U32 *)memPtr); }
+
+ZSTD_STATIC U64 ZSTD_read64(const void *memPtr) { return get_unaligned((const 
U64 *)memPtr); }
+
+ZSTD_STATIC size_t ZSTD_readST(const void *memPtr) { return 
get_unaligned((const size_t *)memPtr); }
+
+ZSTD_STATIC void ZSTD_write16(void *memPtr, U16 value) { put_unaligned(value, 
(U16 *)memPtr); }
+
+ZSTD_STATIC void ZSTD_write32(void *memPtr, U32 value) { put_unaligned(value, 
(U32 *)memPtr); }
+
+ZSTD_STATIC void ZSTD_write64(void *memPtr, U64 value) { put_unaligned(value, 
(U64 *)memPtr); }
+
+/*=== Little endian r/w ===*/
+
+ZSTD_STATIC U16 ZSTD_readLE16(const void *memPtr) { return 
get_unaligned_le16(memPtr); }
+
+ZSTD_STATIC void ZSTD_writeLE16(void *memPtr, U16 val) { 
put_unaligned_le16(val, memPtr); }
+
+ZSTD_STATIC U32 ZSTD_readLE24(const void *memPtr) { return 
ZSTD_readLE16(memPtr) + (((const BYTE *)memPtr)[2] << 16); }
+
+ZSTD_STATIC void ZSTD_writeLE24(void *memPtr, U32 val)
+{
+       ZSTD_writeLE16(memPtr, (U16)val);
+       ((BYTE *)memPtr)[2] = (BYTE)(val >> 16);
+}
+
+ZSTD_STATIC U32 ZSTD_readLE32(const void *memPtr) { return 
get_unaligned_le32(memPtr); }
+
+ZSTD_STATIC void ZSTD_writeLE32(void *memPtr, U32 val32) { 
put_unaligned_le32(val32, memPtr); }
+
+ZSTD_STATIC U64 ZSTD_readLE64(const void *memPtr) { return 
get_unaligned_le64(memPtr); }
+
+ZSTD_STATIC void ZSTD_writeLE64(void *memPtr, U64 val64) { 
put_unaligned_le64(val64, memPtr); }
+
+ZSTD_STATIC size_t ZSTD_readLEST(const void *memPtr)
+{
+       if (ZSTD_32bits())
+               return (size_t)ZSTD_readLE32(memPtr);
+       else
+               return (size_t)ZSTD_readLE64(memPtr);
+}
+
+ZSTD_STATIC void ZSTD_writeLEST(void *memPtr, size_t val)
+{
+       if (ZSTD_32bits())
+               ZSTD_writeLE32(memPtr, (U32)val);
+       else
+               ZSTD_writeLE64(memPtr, (U64)val);
+}
+
+/*=== Big endian r/w ===*/
+
+ZSTD_STATIC U32 ZSTD_readBE32(const void *memPtr) { return 
get_unaligned_be32(memPtr); }
+
+ZSTD_STATIC void ZSTD_writeBE32(void *memPtr, U32 val32) { 
put_unaligned_be32(val32, memPtr); }
+
+ZSTD_STATIC U64 ZSTD_readBE64(const void *memPtr) { return 
get_unaligned_be64(memPtr); }
+
+ZSTD_STATIC void ZSTD_writeBE64(void *memPtr, U64 val64) { 
put_unaligned_be64(val64, memPtr); }
+
+ZSTD_STATIC size_t ZSTD_readBEST(const void *memPtr)
+{
+       if (ZSTD_32bits())
+               return (size_t)ZSTD_readBE32(memPtr);
+       else
+               return (size_t)ZSTD_readBE64(memPtr);
+}
+
+ZSTD_STATIC void ZSTD_writeBEST(void *memPtr, size_t val)
+{
+       if (ZSTD_32bits())
+               ZSTD_writeBE32(memPtr, (U32)val);
+       else
+               ZSTD_writeBE64(memPtr, (U64)val);
+}
+
+/* function safe only for comparisons */
+ZSTD_STATIC U32 ZSTD_readMINMATCH(const void *memPtr, U32 length)
+{
+       switch (length) {
+       default:
+       case 4: return ZSTD_read32(memPtr);
+       case 3:
+               if (ZSTD_isLittleEndian())
+                       return ZSTD_read32(memPtr) << 8;
+               else
+                       return ZSTD_read32(memPtr) >> 8;
+       }
+}
+
+#endif /* MEM_H_MODULE */
diff --git a/grub-core/lib/zstd/xxhash.c b/grub-core/lib/zstd/xxhash.c
new file mode 100644
index 000000000..aa61e2a38
--- /dev/null
+++ b/grub-core/lib/zstd/xxhash.c
@@ -0,0 +1,500 @@
+/*
+ * xxHash - Extremely Fast Hash algorithm
+ * Copyright (C) 2012-2016, Yann Collet.
+ *
+ * BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *   * Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above
+ *     copyright notice, this list of conditions and the following disclaimer
+ *     in the documentation and/or other materials provided with the
+ *     distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * This program is free software; you can redistribute it and/or modify it 
under
+ * the terms of the GNU General Public License version 2 as published by the
+ * Free Software Foundation. This program is dual-licensed; you may select
+ * either version 2 of the GNU General Public License ("GPL") or BSD license
+ * ("BSD").
+ *
+ * You can contact the author at:
+ * - xxHash homepage: http://cyan4973.github.io/xxHash/
+ * - xxHash source repository: https://github.com/Cyan4973/xxHash
+ */
+
+#include <asm/unaligned.h>
+#include <linux/errno.h>
+#include <linux/compiler.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/xxhash.h>
+
+/*-*************************************
+ * Macros
+ **************************************/
+#define xxh_rotl32(x, r) ((x << r) | (x >> (32 - r)))
+#define xxh_rotl64(x, r) ((x << r) | (x >> (64 - r)))
+
+#ifdef __LITTLE_ENDIAN
+# define XXH_CPU_LITTLE_ENDIAN 1
+#else
+# define XXH_CPU_LITTLE_ENDIAN 0
+#endif
+
+/*-*************************************
+ * Constants
+ **************************************/
+static const uint32_t PRIME32_1 = 2654435761U;
+static const uint32_t PRIME32_2 = 2246822519U;
+static const uint32_t PRIME32_3 = 3266489917U;
+static const uint32_t PRIME32_4 =  668265263U;
+static const uint32_t PRIME32_5 =  374761393U;
+
+static const uint64_t PRIME64_1 = 11400714785074694791ULL;
+static const uint64_t PRIME64_2 = 14029467366897019727ULL;
+static const uint64_t PRIME64_3 =  1609587929392839161ULL;
+static const uint64_t PRIME64_4 =  9650029242287828579ULL;
+static const uint64_t PRIME64_5 =  2870177450012600261ULL;
+
+/*-**************************
+ *  Utils
+ ***************************/
+void xxh32_copy_state(struct xxh32_state *dst, const struct xxh32_state *src)
+{
+       memcpy(dst, src, sizeof(*dst));
+}
+EXPORT_SYMBOL(xxh32_copy_state);
+
+void xxh64_copy_state(struct xxh64_state *dst, const struct xxh64_state *src)
+{
+       memcpy(dst, src, sizeof(*dst));
+}
+EXPORT_SYMBOL(xxh64_copy_state);
+
+/*-***************************
+ * Simple Hash Functions
+ ****************************/
+static uint32_t xxh32_round(uint32_t seed, const uint32_t input)
+{
+       seed += input * PRIME32_2;
+       seed = xxh_rotl32(seed, 13);
+       seed *= PRIME32_1;
+       return seed;
+}
+
+uint32_t xxh32(const void *input, const size_t len, const uint32_t seed)
+{
+       const uint8_t *p = (const uint8_t *)input;
+       const uint8_t *b_end = p + len;
+       uint32_t h32;
+
+       if (len >= 16) {
+               const uint8_t *const limit = b_end - 16;
+               uint32_t v1 = seed + PRIME32_1 + PRIME32_2;
+               uint32_t v2 = seed + PRIME32_2;
+               uint32_t v3 = seed + 0;
+               uint32_t v4 = seed - PRIME32_1;
+
+               do {
+                       v1 = xxh32_round(v1, get_unaligned_le32(p));
+                       p += 4;
+                       v2 = xxh32_round(v2, get_unaligned_le32(p));
+                       p += 4;
+                       v3 = xxh32_round(v3, get_unaligned_le32(p));
+                       p += 4;
+                       v4 = xxh32_round(v4, get_unaligned_le32(p));
+                       p += 4;
+               } while (p <= limit);
+
+               h32 = xxh_rotl32(v1, 1) + xxh_rotl32(v2, 7) +
+                       xxh_rotl32(v3, 12) + xxh_rotl32(v4, 18);
+       } else {
+               h32 = seed + PRIME32_5;
+       }
+
+       h32 += (uint32_t)len;
+
+       while (p + 4 <= b_end) {
+               h32 += get_unaligned_le32(p) * PRIME32_3;
+               h32 = xxh_rotl32(h32, 17) * PRIME32_4;
+               p += 4;
+       }
+
+       while (p < b_end) {
+               h32 += (*p) * PRIME32_5;
+               h32 = xxh_rotl32(h32, 11) * PRIME32_1;
+               p++;
+       }
+
+       h32 ^= h32 >> 15;
+       h32 *= PRIME32_2;
+       h32 ^= h32 >> 13;
+       h32 *= PRIME32_3;
+       h32 ^= h32 >> 16;
+
+       return h32;
+}
+EXPORT_SYMBOL(xxh32);
+
+static uint64_t xxh64_round(uint64_t acc, const uint64_t input)
+{
+       acc += input * PRIME64_2;
+       acc = xxh_rotl64(acc, 31);
+       acc *= PRIME64_1;
+       return acc;
+}
+
+static uint64_t xxh64_merge_round(uint64_t acc, uint64_t val)
+{
+       val = xxh64_round(0, val);
+       acc ^= val;
+       acc = acc * PRIME64_1 + PRIME64_4;
+       return acc;
+}
+
+uint64_t xxh64(const void *input, const size_t len, const uint64_t seed)
+{
+       const uint8_t *p = (const uint8_t *)input;
+       const uint8_t *const b_end = p + len;
+       uint64_t h64;
+
+       if (len >= 32) {
+               const uint8_t *const limit = b_end - 32;
+               uint64_t v1 = seed + PRIME64_1 + PRIME64_2;
+               uint64_t v2 = seed + PRIME64_2;
+               uint64_t v3 = seed + 0;
+               uint64_t v4 = seed - PRIME64_1;
+
+               do {
+                       v1 = xxh64_round(v1, get_unaligned_le64(p));
+                       p += 8;
+                       v2 = xxh64_round(v2, get_unaligned_le64(p));
+                       p += 8;
+                       v3 = xxh64_round(v3, get_unaligned_le64(p));
+                       p += 8;
+                       v4 = xxh64_round(v4, get_unaligned_le64(p));
+                       p += 8;
+               } while (p <= limit);
+
+               h64 = xxh_rotl64(v1, 1) + xxh_rotl64(v2, 7) +
+                       xxh_rotl64(v3, 12) + xxh_rotl64(v4, 18);
+               h64 = xxh64_merge_round(h64, v1);
+               h64 = xxh64_merge_round(h64, v2);
+               h64 = xxh64_merge_round(h64, v3);
+               h64 = xxh64_merge_round(h64, v4);
+
+       } else {
+               h64  = seed + PRIME64_5;
+       }
+
+       h64 += (uint64_t)len;
+
+       while (p + 8 <= b_end) {
+               const uint64_t k1 = xxh64_round(0, get_unaligned_le64(p));
+
+               h64 ^= k1;
+               h64 = xxh_rotl64(h64, 27) * PRIME64_1 + PRIME64_4;
+               p += 8;
+       }
+
+       if (p + 4 <= b_end) {
+               h64 ^= (uint64_t)(get_unaligned_le32(p)) * PRIME64_1;
+               h64 = xxh_rotl64(h64, 23) * PRIME64_2 + PRIME64_3;
+               p += 4;
+       }
+
+       while (p < b_end) {
+               h64 ^= (*p) * PRIME64_5;
+               h64 = xxh_rotl64(h64, 11) * PRIME64_1;
+               p++;
+       }
+
+       h64 ^= h64 >> 33;
+       h64 *= PRIME64_2;
+       h64 ^= h64 >> 29;
+       h64 *= PRIME64_3;
+       h64 ^= h64 >> 32;
+
+       return h64;
+}
+EXPORT_SYMBOL(xxh64);
+
+/*-**************************************************
+ * Advanced Hash Functions
+ ***************************************************/
+void xxh32_reset(struct xxh32_state *statePtr, const uint32_t seed)
+{
+       /* use a local state for memcpy() to avoid strict-aliasing warnings */
+       struct xxh32_state state;
+
+       memset(&state, 0, sizeof(state));
+       state.v1 = seed + PRIME32_1 + PRIME32_2;
+       state.v2 = seed + PRIME32_2;
+       state.v3 = seed + 0;
+       state.v4 = seed - PRIME32_1;
+       memcpy(statePtr, &state, sizeof(state));
+}
+EXPORT_SYMBOL(xxh32_reset);
+
+void xxh64_reset(struct xxh64_state *statePtr, const uint64_t seed)
+{
+       /* use a local state for memcpy() to avoid strict-aliasing warnings */
+       struct xxh64_state state;
+
+       memset(&state, 0, sizeof(state));
+       state.v1 = seed + PRIME64_1 + PRIME64_2;
+       state.v2 = seed + PRIME64_2;
+       state.v3 = seed + 0;
+       state.v4 = seed - PRIME64_1;
+       memcpy(statePtr, &state, sizeof(state));
+}
+EXPORT_SYMBOL(xxh64_reset);
+
+int xxh32_update(struct xxh32_state *state, const void *input, const size_t 
len)
+{
+       const uint8_t *p = (const uint8_t *)input;
+       const uint8_t *const b_end = p + len;
+
+       if (input == NULL)
+               return -EINVAL;
+
+       state->total_len_32 += (uint32_t)len;
+       state->large_len |= (len >= 16) | (state->total_len_32 >= 16);
+
+       if (state->memsize + len < 16) { /* fill in tmp buffer */
+               memcpy((uint8_t *)(state->mem32) + state->memsize, input, len);
+               state->memsize += (uint32_t)len;
+               return 0;
+       }
+
+       if (state->memsize) { /* some data left from previous update */
+               const uint32_t *p32 = state->mem32;
+
+               memcpy((uint8_t *)(state->mem32) + state->memsize, input,
+                       16 - state->memsize);
+
+               state->v1 = xxh32_round(state->v1, get_unaligned_le32(p32));
+               p32++;
+               state->v2 = xxh32_round(state->v2, get_unaligned_le32(p32));
+               p32++;
+               state->v3 = xxh32_round(state->v3, get_unaligned_le32(p32));
+               p32++;
+               state->v4 = xxh32_round(state->v4, get_unaligned_le32(p32));
+               p32++;
+
+               p += 16-state->memsize;
+               state->memsize = 0;
+       }
+
+       if (p <= b_end - 16) {
+               const uint8_t *const limit = b_end - 16;
+               uint32_t v1 = state->v1;
+               uint32_t v2 = state->v2;
+               uint32_t v3 = state->v3;
+               uint32_t v4 = state->v4;
+
+               do {
+                       v1 = xxh32_round(v1, get_unaligned_le32(p));
+                       p += 4;
+                       v2 = xxh32_round(v2, get_unaligned_le32(p));
+                       p += 4;
+                       v3 = xxh32_round(v3, get_unaligned_le32(p));
+                       p += 4;
+                       v4 = xxh32_round(v4, get_unaligned_le32(p));
+                       p += 4;
+               } while (p <= limit);
+
+               state->v1 = v1;
+               state->v2 = v2;
+               state->v3 = v3;
+               state->v4 = v4;
+       }
+
+       if (p < b_end) {
+               memcpy(state->mem32, p, (size_t)(b_end-p));
+               state->memsize = (uint32_t)(b_end-p);
+       }
+
+       return 0;
+}
+EXPORT_SYMBOL(xxh32_update);
+
+uint32_t xxh32_digest(const struct xxh32_state *state)
+{
+       const uint8_t *p = (const uint8_t *)state->mem32;
+       const uint8_t *const b_end = (const uint8_t *)(state->mem32) +
+               state->memsize;
+       uint32_t h32;
+
+       if (state->large_len) {
+               h32 = xxh_rotl32(state->v1, 1) + xxh_rotl32(state->v2, 7) +
+                       xxh_rotl32(state->v3, 12) + xxh_rotl32(state->v4, 18);
+       } else {
+               h32 = state->v3 /* == seed */ + PRIME32_5;
+       }
+
+       h32 += state->total_len_32;
+
+       while (p + 4 <= b_end) {
+               h32 += get_unaligned_le32(p) * PRIME32_3;
+               h32 = xxh_rotl32(h32, 17) * PRIME32_4;
+               p += 4;
+       }
+
+       while (p < b_end) {
+               h32 += (*p) * PRIME32_5;
+               h32 = xxh_rotl32(h32, 11) * PRIME32_1;
+               p++;
+       }
+
+       h32 ^= h32 >> 15;
+       h32 *= PRIME32_2;
+       h32 ^= h32 >> 13;
+       h32 *= PRIME32_3;
+       h32 ^= h32 >> 16;
+
+       return h32;
+}
+EXPORT_SYMBOL(xxh32_digest);
+
+int xxh64_update(struct xxh64_state *state, const void *input, const size_t 
len)
+{
+       const uint8_t *p = (const uint8_t *)input;
+       const uint8_t *const b_end = p + len;
+
+       if (input == NULL)
+               return -EINVAL;
+
+       state->total_len += len;
+
+       if (state->memsize + len < 32) { /* fill in tmp buffer */
+               memcpy(((uint8_t *)state->mem64) + state->memsize, input, len);
+               state->memsize += (uint32_t)len;
+               return 0;
+       }
+
+       if (state->memsize) { /* tmp buffer is full */
+               uint64_t *p64 = state->mem64;
+
+               memcpy(((uint8_t *)p64) + state->memsize, input,
+                       32 - state->memsize);
+
+               state->v1 = xxh64_round(state->v1, get_unaligned_le64(p64));
+               p64++;
+               state->v2 = xxh64_round(state->v2, get_unaligned_le64(p64));
+               p64++;
+               state->v3 = xxh64_round(state->v3, get_unaligned_le64(p64));
+               p64++;
+               state->v4 = xxh64_round(state->v4, get_unaligned_le64(p64));
+
+               p += 32 - state->memsize;
+               state->memsize = 0;
+       }
+
+       if (p + 32 <= b_end) {
+               const uint8_t *const limit = b_end - 32;
+               uint64_t v1 = state->v1;
+               uint64_t v2 = state->v2;
+               uint64_t v3 = state->v3;
+               uint64_t v4 = state->v4;
+
+               do {
+                       v1 = xxh64_round(v1, get_unaligned_le64(p));
+                       p += 8;
+                       v2 = xxh64_round(v2, get_unaligned_le64(p));
+                       p += 8;
+                       v3 = xxh64_round(v3, get_unaligned_le64(p));
+                       p += 8;
+                       v4 = xxh64_round(v4, get_unaligned_le64(p));
+                       p += 8;
+               } while (p <= limit);
+
+               state->v1 = v1;
+               state->v2 = v2;
+               state->v3 = v3;
+               state->v4 = v4;
+       }
+
+       if (p < b_end) {
+               memcpy(state->mem64, p, (size_t)(b_end-p));
+               state->memsize = (uint32_t)(b_end - p);
+       }
+
+       return 0;
+}
+EXPORT_SYMBOL(xxh64_update);
+
+uint64_t xxh64_digest(const struct xxh64_state *state)
+{
+       const uint8_t *p = (const uint8_t *)state->mem64;
+       const uint8_t *const b_end = (const uint8_t *)state->mem64 +
+               state->memsize;
+       uint64_t h64;
+
+       if (state->total_len >= 32) {
+               const uint64_t v1 = state->v1;
+               const uint64_t v2 = state->v2;
+               const uint64_t v3 = state->v3;
+               const uint64_t v4 = state->v4;
+
+               h64 = xxh_rotl64(v1, 1) + xxh_rotl64(v2, 7) +
+                       xxh_rotl64(v3, 12) + xxh_rotl64(v4, 18);
+               h64 = xxh64_merge_round(h64, v1);
+               h64 = xxh64_merge_round(h64, v2);
+               h64 = xxh64_merge_round(h64, v3);
+               h64 = xxh64_merge_round(h64, v4);
+       } else {
+               h64  = state->v3 + PRIME64_5;
+       }
+
+       h64 += (uint64_t)state->total_len;
+
+       while (p + 8 <= b_end) {
+               const uint64_t k1 = xxh64_round(0, get_unaligned_le64(p));
+
+               h64 ^= k1;
+               h64 = xxh_rotl64(h64, 27) * PRIME64_1 + PRIME64_4;
+               p += 8;
+       }
+
+       if (p + 4 <= b_end) {
+               h64 ^= (uint64_t)(get_unaligned_le32(p)) * PRIME64_1;
+               h64 = xxh_rotl64(h64, 23) * PRIME64_2 + PRIME64_3;
+               p += 4;
+       }
+
+       while (p < b_end) {
+               h64 ^= (*p) * PRIME64_5;
+               h64 = xxh_rotl64(h64, 11) * PRIME64_1;
+               p++;
+       }
+
+       h64 ^= h64 >> 33;
+       h64 *= PRIME64_2;
+       h64 ^= h64 >> 29;
+       h64 *= PRIME64_3;
+       h64 ^= h64 >> 32;
+
+       return h64;
+}
+EXPORT_SYMBOL(xxh64_digest);
+
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_DESCRIPTION("xxHash");
diff --git a/grub-core/lib/zstd/xxhash.h b/grub-core/lib/zstd/xxhash.h
new file mode 100644
index 000000000..9e1f42cb5
--- /dev/null
+++ b/grub-core/lib/zstd/xxhash.h
@@ -0,0 +1,236 @@
+/*
+ * xxHash - Extremely Fast Hash algorithm
+ * Copyright (C) 2012-2016, Yann Collet.
+ *
+ * BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *   * Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above
+ *     copyright notice, this list of conditions and the following disclaimer
+ *     in the documentation and/or other materials provided with the
+ *     distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * This program is free software; you can redistribute it and/or modify it 
under
+ * the terms of the GNU General Public License version 2 as published by the
+ * Free Software Foundation. This program is dual-licensed; you may select
+ * either version 2 of the GNU General Public License ("GPL") or BSD license
+ * ("BSD").
+ *
+ * You can contact the author at:
+ * - xxHash homepage: http://cyan4973.github.io/xxHash/
+ * - xxHash source repository: https://github.com/Cyan4973/xxHash
+ */
+
+/*
+ * Notice extracted from xxHash homepage:
+ *
+ * xxHash is an extremely fast Hash algorithm, running at RAM speed limits.
+ * It also successfully passes all tests from the SMHasher suite.
+ *
+ * Comparison (single thread, Windows Seven 32 bits, using SMHasher on a Core 2
+ * Duo @3GHz)
+ *
+ * Name            Speed       Q.Score   Author
+ * xxHash          5.4 GB/s     10
+ * CrapWow         3.2 GB/s      2       Andrew
+ * MumurHash 3a    2.7 GB/s     10       Austin Appleby
+ * SpookyHash      2.0 GB/s     10       Bob Jenkins
+ * SBox            1.4 GB/s      9       Bret Mulvey
+ * Lookup3         1.2 GB/s      9       Bob Jenkins
+ * SuperFastHash   1.2 GB/s      1       Paul Hsieh
+ * CityHash64      1.05 GB/s    10       Pike & Alakuijala
+ * FNV             0.55 GB/s     5       Fowler, Noll, Vo
+ * CRC32           0.43 GB/s     9
+ * MD5-32          0.33 GB/s    10       Ronald L. Rivest
+ * SHA1-32         0.28 GB/s    10
+ *
+ * Q.Score is a measure of quality of the hash function.
+ * It depends on successfully passing SMHasher test set.
+ * 10 is a perfect score.
+ *
+ * A 64-bits version, named xxh64 offers much better speed,
+ * but for 64-bits applications only.
+ * Name     Speed on 64 bits    Speed on 32 bits
+ * xxh64       13.8 GB/s            1.9 GB/s
+ * xxh32        6.8 GB/s            6.0 GB/s
+ */
+
+#ifndef XXHASH_H
+#define XXHASH_H
+
+#include <linux/types.h>
+
+/*-****************************
+ * Simple Hash Functions
+ *****************************/
+
+/**
+ * xxh32() - calculate the 32-bit hash of the input with a given seed.
+ *
+ * @input:  The data to hash.
+ * @length: The length of the data to hash.
+ * @seed:   The seed can be used to alter the result predictably.
+ *
+ * Speed on Core 2 Duo @ 3 GHz (single thread, SMHasher benchmark) : 5.4 GB/s
+ *
+ * Return:  The 32-bit hash of the data.
+ */
+uint32_t xxh32(const void *input, size_t length, uint32_t seed);
+
+/**
+ * xxh64() - calculate the 64-bit hash of the input with a given seed.
+ *
+ * @input:  The data to hash.
+ * @length: The length of the data to hash.
+ * @seed:   The seed can be used to alter the result predictably.
+ *
+ * This function runs 2x faster on 64-bit systems, but slower on 32-bit 
systems.
+ *
+ * Return:  The 64-bit hash of the data.
+ */
+uint64_t xxh64(const void *input, size_t length, uint64_t seed);
+
+/*-****************************
+ * Streaming Hash Functions
+ *****************************/
+
+/*
+ * These definitions are only meant to allow allocation of XXH state
+ * statically, on stack, or in a struct for example.
+ * Do not use members directly.
+ */
+
+/**
+ * struct xxh32_state - private xxh32 state, do not use members directly
+ */
+struct xxh32_state {
+       uint32_t total_len_32;
+       uint32_t large_len;
+       uint32_t v1;
+       uint32_t v2;
+       uint32_t v3;
+       uint32_t v4;
+       uint32_t mem32[4];
+       uint32_t memsize;
+};
+
+/**
+ * struct xxh32_state - private xxh64 state, do not use members directly
+ */
+struct xxh64_state {
+       uint64_t total_len;
+       uint64_t v1;
+       uint64_t v2;
+       uint64_t v3;
+       uint64_t v4;
+       uint64_t mem64[4];
+       uint32_t memsize;
+};
+
+/**
+ * xxh32_reset() - reset the xxh32 state to start a new hashing operation
+ *
+ * @state: The xxh32 state to reset.
+ * @seed:  Initialize the hash state with this seed.
+ *
+ * Call this function on any xxh32_state to prepare for a new hashing 
operation.
+ */
+void xxh32_reset(struct xxh32_state *state, uint32_t seed);
+
+/**
+ * xxh32_update() - hash the data given and update the xxh32 state
+ *
+ * @state:  The xxh32 state to update.
+ * @input:  The data to hash.
+ * @length: The length of the data to hash.
+ *
+ * After calling xxh32_reset() call xxh32_update() as many times as necessary.
+ *
+ * Return:  Zero on success, otherwise an error code.
+ */
+int xxh32_update(struct xxh32_state *state, const void *input, size_t length);
+
+/**
+ * xxh32_digest() - produce the current xxh32 hash
+ *
+ * @state: Produce the current xxh32 hash of this state.
+ *
+ * A hash value can be produced at any time. It is still possible to continue
+ * inserting input into the hash state after a call to xxh32_digest(), and
+ * generate new hashes later on, by calling xxh32_digest() again.
+ *
+ * Return: The xxh32 hash stored in the state.
+ */
+uint32_t xxh32_digest(const struct xxh32_state *state);
+
+/**
+ * xxh64_reset() - reset the xxh64 state to start a new hashing operation
+ *
+ * @state: The xxh64 state to reset.
+ * @seed:  Initialize the hash state with this seed.
+ */
+void xxh64_reset(struct xxh64_state *state, uint64_t seed);
+
+/**
+ * xxh64_update() - hash the data given and update the xxh64 state
+ * @state:  The xxh64 state to update.
+ * @input:  The data to hash.
+ * @length: The length of the data to hash.
+ *
+ * After calling xxh64_reset() call xxh64_update() as many times as necessary.
+ *
+ * Return:  Zero on success, otherwise an error code.
+ */
+int xxh64_update(struct xxh64_state *state, const void *input, size_t length);
+
+/**
+ * xxh64_digest() - produce the current xxh64 hash
+ *
+ * @state: Produce the current xxh64 hash of this state.
+ *
+ * A hash value can be produced at any time. It is still possible to continue
+ * inserting input into the hash state after a call to xxh64_digest(), and
+ * generate new hashes later on, by calling xxh64_digest() again.
+ *
+ * Return: The xxh64 hash stored in the state.
+ */
+uint64_t xxh64_digest(const struct xxh64_state *state);
+
+/*-**************************
+ * Utils
+ ***************************/
+
+/**
+ * xxh32_copy_state() - copy the source state into the destination state
+ *
+ * @src: The source xxh32 state.
+ * @dst: The destination xxh32 state.
+ */
+void xxh32_copy_state(struct xxh32_state *dst, const struct xxh32_state *src);
+
+/**
+ * xxh64_copy_state() - copy the source state into the destination state
+ *
+ * @src: The source xxh64 state.
+ * @dst: The destination xxh64 state.
+ */
+void xxh64_copy_state(struct xxh64_state *dst, const struct xxh64_state *src);
+
+#endif /* XXHASH_H */
diff --git a/grub-core/lib/zstd/zstd.h b/grub-core/lib/zstd/zstd.h
new file mode 100644
index 000000000..249575e24
--- /dev/null
+++ b/grub-core/lib/zstd/zstd.h
@@ -0,0 +1,1157 @@
+/*
+ * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of https://github.com/facebook/zstd.
+ * An additional grant of patent rights can be found in the PATENTS file in the
+ * same directory.
+ *
+ * This program is free software; you can redistribute it and/or modify it 
under
+ * the terms of the GNU General Public License version 2 as published by the
+ * Free Software Foundation. This program is dual-licensed; you may select
+ * either version 2 of the GNU General Public License ("GPL") or BSD license
+ * ("BSD").
+ */
+
+#ifndef ZSTD_H
+#define ZSTD_H
+
+/* ======   Dependency   ======*/
+#include <linux/types.h>   /* size_t */
+
+
+/*-*****************************************************************************
+ * Introduction
+ *
+ * zstd, short for Zstandard, is a fast lossless compression algorithm,
+ * targeting real-time compression scenarios at zlib-level and better
+ * compression ratios. The zstd compression library provides in-memory
+ * compression and decompression functions. The library supports compression
+ * levels from 1 up to ZSTD_maxCLevel() which is 22. Levels >= 20, labeled
+ * ultra, should be used with caution, as they require more memory.
+ * Compression can be done in:
+ *  - a single step, reusing a context (described as Explicit memory 
management)
+ *  - unbounded multiple steps (described as Streaming compression)
+ * The compression ratio achievable on small data can be highly improved using
+ * compression with a dictionary in:
+ *  - a single step (described as Simple dictionary API)
+ *  - a single step, reusing a dictionary (described as Fast dictionary API)
+ 
******************************************************************************/
+
+/*======  Helper functions  ======*/
+
+/**
+ * enum ZSTD_ErrorCode - zstd error codes
+ *
+ * Functions that return size_t can be checked for errors using ZSTD_isError()
+ * and the ZSTD_ErrorCode can be extracted using ZSTD_getErrorCode().
+ */
+typedef enum {
+       ZSTD_error_no_error,
+       ZSTD_error_GENERIC,
+       ZSTD_error_prefix_unknown,
+       ZSTD_error_version_unsupported,
+       ZSTD_error_parameter_unknown,
+       ZSTD_error_frameParameter_unsupported,
+       ZSTD_error_frameParameter_unsupportedBy32bits,
+       ZSTD_error_frameParameter_windowTooLarge,
+       ZSTD_error_compressionParameter_unsupported,
+       ZSTD_error_init_missing,
+       ZSTD_error_memory_allocation,
+       ZSTD_error_stage_wrong,
+       ZSTD_error_dstSize_tooSmall,
+       ZSTD_error_srcSize_wrong,
+       ZSTD_error_corruption_detected,
+       ZSTD_error_checksum_wrong,
+       ZSTD_error_tableLog_tooLarge,
+       ZSTD_error_maxSymbolValue_tooLarge,
+       ZSTD_error_maxSymbolValue_tooSmall,
+       ZSTD_error_dictionary_corrupted,
+       ZSTD_error_dictionary_wrong,
+       ZSTD_error_dictionaryCreation_failed,
+       ZSTD_error_maxCode
+} ZSTD_ErrorCode;
+
+/**
+ * ZSTD_maxCLevel() - maximum compression level available
+ *
+ * Return: Maximum compression level available.
+ */
+int ZSTD_maxCLevel(void);
+/**
+ * ZSTD_compressBound() - maximum compressed size in worst case scenario
+ * @srcSize: The size of the data to compress.
+ *
+ * Return:   The maximum compressed size in the worst case scenario.
+ */
+size_t ZSTD_compressBound(size_t srcSize);
+/**
+ * ZSTD_isError() - tells if a size_t function result is an error code
+ * @code:  The function result to check for error.
+ *
+ * Return: Non-zero iff the code is an error.
+ */
+static __attribute__((unused)) unsigned int ZSTD_isError(size_t code)
+{
+       return code > (size_t)-ZSTD_error_maxCode;
+}
+/**
+ * ZSTD_getErrorCode() - translates an error function result to a 
ZSTD_ErrorCode
+ * @functionResult: The result of a function for which ZSTD_isError() is true.
+ *
+ * Return:          The ZSTD_ErrorCode corresponding to the functionResult or 0
+ *                  if the functionResult isn't an error.
+ */
+static __attribute__((unused)) ZSTD_ErrorCode ZSTD_getErrorCode(
+       size_t functionResult)
+{
+       if (!ZSTD_isError(functionResult))
+               return (ZSTD_ErrorCode)0;
+       return (ZSTD_ErrorCode)(0 - functionResult);
+}
+
+/**
+ * enum ZSTD_strategy - zstd compression search strategy
+ *
+ * From faster to stronger.
+ */
+typedef enum {
+       ZSTD_fast,
+       ZSTD_dfast,
+       ZSTD_greedy,
+       ZSTD_lazy,
+       ZSTD_lazy2,
+       ZSTD_btlazy2,
+       ZSTD_btopt,
+       ZSTD_btopt2
+} ZSTD_strategy;
+
+/**
+ * struct ZSTD_compressionParameters - zstd compression parameters
+ * @windowLog:    Log of the largest match distance. Larger means more
+ *                compression, and more memory needed during decompression.
+ * @chainLog:     Fully searched segment. Larger means more compression, 
slower,
+ *                and more memory (useless for fast).
+ * @hashLog:      Dispatch table. Larger means more compression,
+ *                slower, and more memory.
+ * @searchLog:    Number of searches. Larger means more compression and slower.
+ * @searchLength: Match length searched. Larger means faster decompression,
+ *                sometimes less compression.
+ * @targetLength: Acceptable match size for optimal parser (only). Larger means
+ *                more compression, and slower.
+ * @strategy:     The zstd compression strategy.
+ */
+typedef struct {
+       unsigned int windowLog;
+       unsigned int chainLog;
+       unsigned int hashLog;
+       unsigned int searchLog;
+       unsigned int searchLength;
+       unsigned int targetLength;
+       ZSTD_strategy strategy;
+} ZSTD_compressionParameters;
+
+/**
+ * struct ZSTD_frameParameters - zstd frame parameters
+ * @contentSizeFlag: Controls whether content size will be present in the frame
+ *                   header (when known).
+ * @checksumFlag:    Controls whether a 32-bit checksum is generated at the end
+ *                   of the frame for error detection.
+ * @noDictIDFlag:    Controls whether dictID will be saved into the frame 
header
+ *                   when using dictionary compression.
+ *
+ * The default value is all fields set to 0.
+ */
+typedef struct {
+       unsigned int contentSizeFlag;
+       unsigned int checksumFlag;
+       unsigned int noDictIDFlag;
+} ZSTD_frameParameters;
+
+/**
+ * struct ZSTD_parameters - zstd parameters
+ * @cParams: The compression parameters.
+ * @fParams: The frame parameters.
+ */
+typedef struct {
+       ZSTD_compressionParameters cParams;
+       ZSTD_frameParameters fParams;
+} ZSTD_parameters;
+
+/**
+ * ZSTD_getCParams() - returns ZSTD_compressionParameters for selected level
+ * @compressionLevel: The compression level from 1 to ZSTD_maxCLevel().
+ * @estimatedSrcSize: The estimated source size to compress or 0 if unknown.
+ * @dictSize:         The dictionary size or 0 if a dictionary isn't being 
used.
+ *
+ * Return:            The selected ZSTD_compressionParameters.
+ */
+ZSTD_compressionParameters ZSTD_getCParams(int compressionLevel,
+       unsigned long long estimatedSrcSize, size_t dictSize);
+
+/**
+ * ZSTD_getParams() - returns ZSTD_parameters for selected level
+ * @compressionLevel: The compression level from 1 to ZSTD_maxCLevel().
+ * @estimatedSrcSize: The estimated source size to compress or 0 if unknown.
+ * @dictSize:         The dictionary size or 0 if a dictionary isn't being 
used.
+ *
+ * The same as ZSTD_getCParams() except also selects the default frame
+ * parameters (all zero).
+ *
+ * Return:            The selected ZSTD_parameters.
+ */
+ZSTD_parameters ZSTD_getParams(int compressionLevel,
+       unsigned long long estimatedSrcSize, size_t dictSize);
+
+/*-*************************************
+ * Explicit memory management
+ **************************************/
+
+/**
+ * ZSTD_CCtxWorkspaceBound() - amount of memory needed to initialize a 
ZSTD_CCtx
+ * @cParams: The compression parameters to be used for compression.
+ *
+ * If multiple compression parameters might be used, the caller must call
+ * ZSTD_CCtxWorkspaceBound() for each set of parameters and use the maximum
+ * size.
+ *
+ * Return:   A lower bound on the size of the workspace that is passed to
+ *           ZSTD_initCCtx().
+ */
+size_t ZSTD_CCtxWorkspaceBound(ZSTD_compressionParameters cParams);
+
+/**
+ * struct ZSTD_CCtx - the zstd compression context
+ *
+ * When compressing many times it is recommended to allocate a context just 
once
+ * and reuse it for each successive compression operation.
+ */
+typedef struct ZSTD_CCtx_s ZSTD_CCtx;
+/**
+ * ZSTD_initCCtx() - initialize a zstd compression context
+ * @workspace:     The workspace to emplace the context into. It must outlive
+ *                 the returned context.
+ * @workspaceSize: The size of workspace. Use ZSTD_CCtxWorkspaceBound() to
+ *                 determine how large the workspace must be.
+ *
+ * Return:         A compression context emplaced into workspace.
+ */
+ZSTD_CCtx *ZSTD_initCCtx(void *workspace, size_t workspaceSize);
+
+/**
+ * ZSTD_compressCCtx() - compress src into dst
+ * @ctx:         The context. Must have been initialized with a workspace at
+ *               least as large as ZSTD_CCtxWorkspaceBound(params.cParams).
+ * @dst:         The buffer to compress src into.
+ * @dstCapacity: The size of the destination buffer. May be any size, but
+ *               ZSTD_compressBound(srcSize) is guaranteed to be large enough.
+ * @src:         The data to compress.
+ * @srcSize:     The size of the data to compress.
+ * @params:      The parameters to use for compression. See ZSTD_getParams().
+ *
+ * Return:       The compressed size or an error, which can be checked using
+ *               ZSTD_isError().
+ */
+size_t ZSTD_compressCCtx(ZSTD_CCtx *ctx, void *dst, size_t dstCapacity,
+       const void *src, size_t srcSize, ZSTD_parameters params);
+
+/**
+ * ZSTD_DCtxWorkspaceBound() - amount of memory needed to initialize a 
ZSTD_DCtx
+ *
+ * Return: A lower bound on the size of the workspace that is passed to
+ *         ZSTD_initDCtx().
+ */
+size_t ZSTD_DCtxWorkspaceBound(void);
+
+/**
+ * struct ZSTD_DCtx - the zstd decompression context
+ *
+ * When decompressing many times it is recommended to allocate a context just
+ * once and reuse it for each successive decompression operation.
+ */
+typedef struct ZSTD_DCtx_s ZSTD_DCtx;
+/**
+ * ZSTD_initDCtx() - initialize a zstd decompression context
+ * @workspace:     The workspace to emplace the context into. It must outlive
+ *                 the returned context.
+ * @workspaceSize: The size of workspace. Use ZSTD_DCtxWorkspaceBound() to
+ *                 determine how large the workspace must be.
+ *
+ * Return:         A decompression context emplaced into workspace.
+ */
+ZSTD_DCtx *ZSTD_initDCtx(void *workspace, size_t workspaceSize);
+
+/**
+ * ZSTD_decompressDCtx() - decompress zstd compressed src into dst
+ * @ctx:         The decompression context.
+ * @dst:         The buffer to decompress src into.
+ * @dstCapacity: The size of the destination buffer. Must be at least as large
+ *               as the decompressed size. If the caller cannot upper bound the
+ *               decompressed size, then it's better to use the streaming API.
+ * @src:         The zstd compressed data to decompress. Multiple concatenated
+ *               frames and skippable frames are allowed.
+ * @srcSize:     The exact size of the data to decompress.
+ *
+ * Return:       The decompressed size or an error, which can be checked using
+ *               ZSTD_isError().
+ */
+size_t ZSTD_decompressDCtx(ZSTD_DCtx *ctx, void *dst, size_t dstCapacity,
+       const void *src, size_t srcSize);
+
+/*-************************
+ * Simple dictionary API
+ **************************/
+
+/**
+ * ZSTD_compress_usingDict() - compress src into dst using a dictionary
+ * @ctx:         The context. Must have been initialized with a workspace at
+ *               least as large as ZSTD_CCtxWorkspaceBound(params.cParams).
+ * @dst:         The buffer to compress src into.
+ * @dstCapacity: The size of the destination buffer. May be any size, but
+ *               ZSTD_compressBound(srcSize) is guaranteed to be large enough.
+ * @src:         The data to compress.
+ * @srcSize:     The size of the data to compress.
+ * @dict:        The dictionary to use for compression.
+ * @dictSize:    The size of the dictionary.
+ * @params:      The parameters to use for compression. See ZSTD_getParams().
+ *
+ * Compression using a predefined dictionary. The same dictionary must be used
+ * during decompression.
+ *
+ * Return:       The compressed size or an error, which can be checked using
+ *               ZSTD_isError().
+ */
+size_t ZSTD_compress_usingDict(ZSTD_CCtx *ctx, void *dst, size_t dstCapacity,
+       const void *src, size_t srcSize, const void *dict, size_t dictSize,
+       ZSTD_parameters params);
+
+/**
+ * ZSTD_decompress_usingDict() - decompress src into dst using a dictionary
+ * @ctx:         The decompression context.
+ * @dst:         The buffer to decompress src into.
+ * @dstCapacity: The size of the destination buffer. Must be at least as large
+ *               as the decompressed size. If the caller cannot upper bound the
+ *               decompressed size, then it's better to use the streaming API.
+ * @src:         The zstd compressed data to decompress. Multiple concatenated
+ *               frames and skippable frames are allowed.
+ * @srcSize:     The exact size of the data to decompress.
+ * @dict:        The dictionary to use for decompression. The same dictionary
+ *               must've been used to compress the data.
+ * @dictSize:    The size of the dictionary.
+ *
+ * Return:       The decompressed size or an error, which can be checked using
+ *               ZSTD_isError().
+ */
+size_t ZSTD_decompress_usingDict(ZSTD_DCtx *ctx, void *dst, size_t dstCapacity,
+       const void *src, size_t srcSize, const void *dict, size_t dictSize);
+
+/*-**************************
+ * Fast dictionary API
+ ***************************/
+
+/**
+ * ZSTD_CDictWorkspaceBound() - memory needed to initialize a ZSTD_CDict
+ * @cParams: The compression parameters to be used for compression.
+ *
+ * Return:   A lower bound on the size of the workspace that is passed to
+ *           ZSTD_initCDict().
+ */
+size_t ZSTD_CDictWorkspaceBound(ZSTD_compressionParameters cParams);
+
+/**
+ * struct ZSTD_CDict - a digested dictionary to be used for compression
+ */
+typedef struct ZSTD_CDict_s ZSTD_CDict;
+
+/**
+ * ZSTD_initCDict() - initialize a digested dictionary for compression
+ * @dictBuffer:    The dictionary to digest. The buffer is referenced by the
+ *                 ZSTD_CDict so it must outlive the returned ZSTD_CDict.
+ * @dictSize:      The size of the dictionary.
+ * @params:        The parameters to use for compression. See ZSTD_getParams().
+ * @workspace:     The workspace. It must outlive the returned ZSTD_CDict.
+ * @workspaceSize: The workspace size. Must be at least
+ *                 ZSTD_CDictWorkspaceBound(params.cParams).
+ *
+ * When compressing multiple messages / blocks with the same dictionary it is
+ * recommended to load it just once. The ZSTD_CDict merely references the
+ * dictBuffer, so it must outlive the returned ZSTD_CDict.
+ *
+ * Return:         The digested dictionary emplaced into workspace.
+ */
+ZSTD_CDict *ZSTD_initCDict(const void *dictBuffer, size_t dictSize,
+       ZSTD_parameters params, void *workspace, size_t workspaceSize);
+
+/**
+ * ZSTD_compress_usingCDict() - compress src into dst using a ZSTD_CDict
+ * @ctx:         The context. Must have been initialized with a workspace at
+ *               least as large as ZSTD_CCtxWorkspaceBound(cParams) where
+ *               cParams are the compression parameters used to initialize the
+ *               cdict.
+ * @dst:         The buffer to compress src into.
+ * @dstCapacity: The size of the destination buffer. May be any size, but
+ *               ZSTD_compressBound(srcSize) is guaranteed to be large enough.
+ * @src:         The data to compress.
+ * @srcSize:     The size of the data to compress.
+ * @cdict:       The digested dictionary to use for compression.
+ * @params:      The parameters to use for compression. See ZSTD_getParams().
+ *
+ * Compression using a digested dictionary. The same dictionary must be used
+ * during decompression.
+ *
+ * Return:       The compressed size or an error, which can be checked using
+ *               ZSTD_isError().
+ */
+size_t ZSTD_compress_usingCDict(ZSTD_CCtx *cctx, void *dst, size_t dstCapacity,
+       const void *src, size_t srcSize, const ZSTD_CDict *cdict);
+
+
+/**
+ * ZSTD_DDictWorkspaceBound() - memory needed to initialize a ZSTD_DDict
+ *
+ * Return:  A lower bound on the size of the workspace that is passed to
+ *          ZSTD_initDDict().
+ */
+size_t ZSTD_DDictWorkspaceBound(void);
+
+/**
+ * struct ZSTD_DDict - a digested dictionary to be used for decompression
+ */
+typedef struct ZSTD_DDict_s ZSTD_DDict;
+
+/**
+ * ZSTD_initDDict() - initialize a digested dictionary for decompression
+ * @dictBuffer:    The dictionary to digest. The buffer is referenced by the
+ *                 ZSTD_DDict so it must outlive the returned ZSTD_DDict.
+ * @dictSize:      The size of the dictionary.
+ * @workspace:     The workspace. It must outlive the returned ZSTD_DDict.
+ * @workspaceSize: The workspace size. Must be at least
+ *                 ZSTD_DDictWorkspaceBound().
+ *
+ * When decompressing multiple messages / blocks with the same dictionary it is
+ * recommended to load it just once. The ZSTD_DDict merely references the
+ * dictBuffer, so it must outlive the returned ZSTD_DDict.
+ *
+ * Return:         The digested dictionary emplaced into workspace.
+ */
+ZSTD_DDict *ZSTD_initDDict(const void *dictBuffer, size_t dictSize,
+       void *workspace, size_t workspaceSize);
+
+/**
+ * ZSTD_decompress_usingDDict() - decompress src into dst using a ZSTD_DDict
+ * @ctx:         The decompression context.
+ * @dst:         The buffer to decompress src into.
+ * @dstCapacity: The size of the destination buffer. Must be at least as large
+ *               as the decompressed size. If the caller cannot upper bound the
+ *               decompressed size, then it's better to use the streaming API.
+ * @src:         The zstd compressed data to decompress. Multiple concatenated
+ *               frames and skippable frames are allowed.
+ * @srcSize:     The exact size of the data to decompress.
+ * @ddict:       The digested dictionary to use for decompression. The same
+ *               dictionary must've been used to compress the data.
+ *
+ * Return:       The decompressed size or an error, which can be checked using
+ *               ZSTD_isError().
+ */
+size_t ZSTD_decompress_usingDDict(ZSTD_DCtx *dctx, void *dst,
+       size_t dstCapacity, const void *src, size_t srcSize,
+       const ZSTD_DDict *ddict);
+
+
+/*-**************************
+ * Streaming
+ ***************************/
+
+/**
+ * struct ZSTD_inBuffer - input buffer for streaming
+ * @src:  Start of the input buffer.
+ * @size: Size of the input buffer.
+ * @pos:  Position where reading stopped. Will be updated.
+ *        Necessarily 0 <= pos <= size.
+ */
+typedef struct ZSTD_inBuffer_s {
+       const void *src;
+       size_t size;
+       size_t pos;
+} ZSTD_inBuffer;
+
+/**
+ * struct ZSTD_outBuffer - output buffer for streaming
+ * @dst:  Start of the output buffer.
+ * @size: Size of the output buffer.
+ * @pos:  Position where writing stopped. Will be updated.
+ *        Necessarily 0 <= pos <= size.
+ */
+typedef struct ZSTD_outBuffer_s {
+       void *dst;
+       size_t size;
+       size_t pos;
+} ZSTD_outBuffer;
+
+
+
+/*-*****************************************************************************
+ * Streaming compression - HowTo
+ *
+ * A ZSTD_CStream object is required to track streaming operation.
+ * Use ZSTD_initCStream() to initialize a ZSTD_CStream object.
+ * ZSTD_CStream objects can be reused multiple times on consecutive compression
+ * operations. It is recommended to re-use ZSTD_CStream in situations where 
many
+ * streaming operations will be achieved consecutively. Use one separate
+ * ZSTD_CStream per thread for parallel execution.
+ *
+ * Use ZSTD_compressStream() repetitively to consume input stream.
+ * The function will automatically update both `pos` fields.
+ * Note that it may not consume the entire input, in which case `pos < size`,
+ * and it's up to the caller to present again remaining data.
+ * It returns a hint for the preferred number of bytes to use as an input for
+ * the next function call.
+ *
+ * At any moment, it's possible to flush whatever data remains within internal
+ * buffer, using ZSTD_flushStream(). `output->pos` will be updated. There might
+ * still be some content left within the internal buffer if `output->size` is
+ * too small. It returns the number of bytes left in the internal buffer and
+ * must be called until it returns 0.
+ *
+ * ZSTD_endStream() instructs to finish a frame. It will perform a flush and
+ * write frame epilogue. The epilogue is required for decoders to consider a
+ * frame completed. Similar to ZSTD_flushStream(), it may not be able to flush
+ * the full content if `output->size` is too small. In which case, call again
+ * ZSTD_endStream() to complete the flush. It returns the number of bytes left
+ * in the internal buffer and must be called until it returns 0.
+ 
******************************************************************************/
+
+/**
+ * ZSTD_CStreamWorkspaceBound() - memory needed to initialize a ZSTD_CStream
+ * @cParams: The compression parameters to be used for compression.
+ *
+ * Return:   A lower bound on the size of the workspace that is passed to
+ *           ZSTD_initCStream() and ZSTD_initCStream_usingCDict().
+ */
+size_t ZSTD_CStreamWorkspaceBound(ZSTD_compressionParameters cParams);
+
+/**
+ * struct ZSTD_CStream - the zstd streaming compression context
+ */
+typedef struct ZSTD_CStream_s ZSTD_CStream;
+
+/*===== ZSTD_CStream management functions =====*/
+/**
+ * ZSTD_initCStream() - initialize a zstd streaming compression context
+ * @params:         The zstd compression parameters.
+ * @pledgedSrcSize: If params.fParams.contentSizeFlag == 1 then the caller must
+ *                  pass the source size (zero means empty source). Otherwise,
+ *                  the caller may optionally pass the source size, or zero if
+ *                  unknown.
+ * @workspace:      The workspace to emplace the context into. It must outlive
+ *                  the returned context.
+ * @workspaceSize:  The size of workspace.
+ *                  Use ZSTD_CStreamWorkspaceBound(params.cParams) to determine
+ *                  how large the workspace must be.
+ *
+ * Return:          The zstd streaming compression context.
+ */
+ZSTD_CStream *ZSTD_initCStream(ZSTD_parameters params,
+       unsigned long long pledgedSrcSize, void *workspace,
+       size_t workspaceSize);
+
+/**
+ * ZSTD_initCStream_usingCDict() - initialize a streaming compression context
+ * @cdict:          The digested dictionary to use for compression.
+ * @pledgedSrcSize: Optionally the source size, or zero if unknown.
+ * @workspace:      The workspace to emplace the context into. It must outlive
+ *                  the returned context.
+ * @workspaceSize:  The size of workspace. Call ZSTD_CStreamWorkspaceBound()
+ *                  with the cParams used to initialize the cdict to determine
+ *                  how large the workspace must be.
+ *
+ * Return:          The zstd streaming compression context.
+ */
+ZSTD_CStream *ZSTD_initCStream_usingCDict(const ZSTD_CDict *cdict,
+       unsigned long long pledgedSrcSize, void *workspace,
+       size_t workspaceSize);
+
+/*===== Streaming compression functions =====*/
+/**
+ * ZSTD_resetCStream() - reset the context using parameters from creation
+ * @zcs:            The zstd streaming compression context to reset.
+ * @pledgedSrcSize: Optionally the source size, or zero if unknown.
+ *
+ * Resets the context using the parameters from creation. Skips dictionary
+ * loading, since it can be reused. If `pledgedSrcSize` is non-zero the frame
+ * content size is always written into the frame header.
+ *
+ * Return:          Zero or an error, which can be checked using 
ZSTD_isError().
+ */
+size_t ZSTD_resetCStream(ZSTD_CStream *zcs, unsigned long long pledgedSrcSize);
+/**
+ * ZSTD_compressStream() - streaming compress some of input into output
+ * @zcs:    The zstd streaming compression context.
+ * @output: Destination buffer. `output->pos` is updated to indicate how much
+ *          compressed data was written.
+ * @input:  Source buffer. `input->pos` is updated to indicate how much data 
was
+ *          read. Note that it may not consume the entire input, in which case
+ *          `input->pos < input->size`, and it's up to the caller to present
+ *          remaining data again.
+ *
+ * The `input` and `output` buffers may be any size. Guaranteed to make some
+ * forward progress if `input` and `output` are not empty.
+ *
+ * Return:  A hint for the number of bytes to use as the input for the next
+ *          function call or an error, which can be checked using
+ *          ZSTD_isError().
+ */
+size_t ZSTD_compressStream(ZSTD_CStream *zcs, ZSTD_outBuffer *output,
+       ZSTD_inBuffer *input);
+/**
+ * ZSTD_flushStream() - flush internal buffers into output
+ * @zcs:    The zstd streaming compression context.
+ * @output: Destination buffer. `output->pos` is updated to indicate how much
+ *          compressed data was written.
+ *
+ * ZSTD_flushStream() must be called until it returns 0, meaning all the data
+ * has been flushed. Since ZSTD_flushStream() causes a block to be ended,
+ * calling it too often will degrade the compression ratio.
+ *
+ * Return:  The number of bytes still present within internal buffers or an
+ *          error, which can be checked using ZSTD_isError().
+ */
+size_t ZSTD_flushStream(ZSTD_CStream *zcs, ZSTD_outBuffer *output);
+/**
+ * ZSTD_endStream() - flush internal buffers into output and end the frame
+ * @zcs:    The zstd streaming compression context.
+ * @output: Destination buffer. `output->pos` is updated to indicate how much
+ *          compressed data was written.
+ *
+ * ZSTD_endStream() must be called until it returns 0, meaning all the data has
+ * been flushed and the frame epilogue has been written.
+ *
+ * Return:  The number of bytes still present within internal buffers or an
+ *          error, which can be checked using ZSTD_isError().
+ */
+size_t ZSTD_endStream(ZSTD_CStream *zcs, ZSTD_outBuffer *output);
+
+/**
+ * ZSTD_CStreamInSize() - recommended size for the input buffer
+ *
+ * Return: The recommended size for the input buffer.
+ */
+size_t ZSTD_CStreamInSize(void);
+/**
+ * ZSTD_CStreamOutSize() - recommended size for the output buffer
+ *
+ * When the output buffer is at least this large, it is guaranteed to be large
+ * enough to flush at least one complete compressed block.
+ *
+ * Return: The recommended size for the output buffer.
+ */
+size_t ZSTD_CStreamOutSize(void);
+
+
+
+/*-*****************************************************************************
+ * Streaming decompression - HowTo
+ *
+ * A ZSTD_DStream object is required to track streaming operations.
+ * Use ZSTD_initDStream() to initialize a ZSTD_DStream object.
+ * ZSTD_DStream objects can be re-used multiple times.
+ *
+ * Use ZSTD_decompressStream() repetitively to consume your input.
+ * The function will update both `pos` fields.
+ * If `input->pos < input->size`, some input has not been consumed.
+ * It's up to the caller to present again remaining data.
+ * If `output->pos < output->size`, decoder has flushed everything it could.
+ * Returns 0 iff a frame is completely decoded and fully flushed.
+ * Otherwise it returns a suggested next input size that will never load more
+ * than the current frame.
+ 
******************************************************************************/
+
+/**
+ * ZSTD_DStreamWorkspaceBound() - memory needed to initialize a ZSTD_DStream
+ * @maxWindowSize: The maximum window size allowed for compressed frames.
+ *
+ * Return:         A lower bound on the size of the workspace that is passed to
+ *                 ZSTD_initDStream() and ZSTD_initDStream_usingDDict().
+ */
+size_t ZSTD_DStreamWorkspaceBound(size_t maxWindowSize);
+
+/**
+ * struct ZSTD_DStream - the zstd streaming decompression context
+ */
+typedef struct ZSTD_DStream_s ZSTD_DStream;
+/*===== ZSTD_DStream management functions =====*/
+/**
+ * ZSTD_initDStream() - initialize a zstd streaming decompression context
+ * @maxWindowSize: The maximum window size allowed for compressed frames.
+ * @workspace:     The workspace to emplace the context into. It must outlive
+ *                 the returned context.
+ * @workspaceSize: The size of workspace.
+ *                 Use ZSTD_DStreamWorkspaceBound(maxWindowSize) to determine
+ *                 how large the workspace must be.
+ *
+ * Return:         The zstd streaming decompression context.
+ */
+ZSTD_DStream *ZSTD_initDStream(size_t maxWindowSize, void *workspace,
+       size_t workspaceSize);
+/**
+ * ZSTD_initDStream_usingDDict() - initialize streaming decompression context
+ * @maxWindowSize: The maximum window size allowed for compressed frames.
+ * @ddict:         The digested dictionary to use for decompression.
+ * @workspace:     The workspace to emplace the context into. It must outlive
+ *                 the returned context.
+ * @workspaceSize: The size of workspace.
+ *                 Use ZSTD_DStreamWorkspaceBound(maxWindowSize) to determine
+ *                 how large the workspace must be.
+ *
+ * Return:         The zstd streaming decompression context.
+ */
+ZSTD_DStream *ZSTD_initDStream_usingDDict(size_t maxWindowSize,
+       const ZSTD_DDict *ddict, void *workspace, size_t workspaceSize);
+
+/*===== Streaming decompression functions =====*/
+/**
+ * ZSTD_resetDStream() - reset the context using parameters from creation
+ * @zds:   The zstd streaming decompression context to reset.
+ *
+ * Resets the context using the parameters from creation. Skips dictionary
+ * loading, since it can be reused.
+ *
+ * Return: Zero or an error, which can be checked using ZSTD_isError().
+ */
+size_t ZSTD_resetDStream(ZSTD_DStream *zds);
+/**
+ * ZSTD_decompressStream() - streaming decompress some of input into output
+ * @zds:    The zstd streaming decompression context.
+ * @output: Destination buffer. `output.pos` is updated to indicate how much
+ *          decompressed data was written.
+ * @input:  Source buffer. `input.pos` is updated to indicate how much data was
+ *          read. Note that it may not consume the entire input, in which case
+ *          `input.pos < input.size`, and it's up to the caller to present
+ *          remaining data again.
+ *
+ * The `input` and `output` buffers may be any size. Guaranteed to make some
+ * forward progress if `input` and `output` are not empty.
+ * ZSTD_decompressStream() will not consume the last byte of the frame until
+ * the entire frame is flushed.
+ *
+ * Return:  Returns 0 iff a frame is completely decoded and fully flushed.
+ *          Otherwise returns a hint for the number of bytes to use as the 
input
+ *          for the next function call or an error, which can be checked using
+ *          ZSTD_isError(). The size hint will never load more than the frame.
+ */
+size_t ZSTD_decompressStream(ZSTD_DStream *zds, ZSTD_outBuffer *output,
+       ZSTD_inBuffer *input);
+
+/**
+ * ZSTD_DStreamInSize() - recommended size for the input buffer
+ *
+ * Return: The recommended size for the input buffer.
+ */
+size_t ZSTD_DStreamInSize(void);
+/**
+ * ZSTD_DStreamOutSize() - recommended size for the output buffer
+ *
+ * When the output buffer is at least this large, it is guaranteed to be large
+ * enough to flush at least one complete decompressed block.
+ *
+ * Return: The recommended size for the output buffer.
+ */
+size_t ZSTD_DStreamOutSize(void);
+
+
+/* --- Constants ---*/
+#define ZSTD_MAGICNUMBER            0xFD2FB528   /* >= v0.8.0 */
+#define ZSTD_MAGIC_SKIPPABLE_START  0x184D2A50U
+
+#define ZSTD_CONTENTSIZE_UNKNOWN (0ULL - 1)
+#define ZSTD_CONTENTSIZE_ERROR   (0ULL - 2)
+
+#define ZSTD_WINDOWLOG_MAX_32  27
+#define ZSTD_WINDOWLOG_MAX_64  27
+#define ZSTD_WINDOWLOG_MAX \
+       ((unsigned int)(sizeof(size_t) == 4 \
+               ? ZSTD_WINDOWLOG_MAX_32 \
+               : ZSTD_WINDOWLOG_MAX_64))
+#define ZSTD_WINDOWLOG_MIN 10
+#define ZSTD_HASHLOG_MAX ZSTD_WINDOWLOG_MAX
+#define ZSTD_HASHLOG_MIN        6
+#define ZSTD_CHAINLOG_MAX     (ZSTD_WINDOWLOG_MAX+1)
+#define ZSTD_CHAINLOG_MIN      ZSTD_HASHLOG_MIN
+#define ZSTD_HASHLOG3_MAX      17
+#define ZSTD_SEARCHLOG_MAX    (ZSTD_WINDOWLOG_MAX-1)
+#define ZSTD_SEARCHLOG_MIN      1
+/* only for ZSTD_fast, other strategies are limited to 6 */
+#define ZSTD_SEARCHLENGTH_MAX   7
+/* only for ZSTD_btopt, other strategies are limited to 4 */
+#define ZSTD_SEARCHLENGTH_MIN   3
+#define ZSTD_TARGETLENGTH_MIN   4
+#define ZSTD_TARGETLENGTH_MAX 999
+
+/* for static allocation */
+#define ZSTD_FRAMEHEADERSIZE_MAX 18
+#define ZSTD_FRAMEHEADERSIZE_MIN  6
+static const size_t ZSTD_frameHeaderSize_prefix = 5;
+static const size_t ZSTD_frameHeaderSize_min = ZSTD_FRAMEHEADERSIZE_MIN;
+static const size_t ZSTD_frameHeaderSize_max = ZSTD_FRAMEHEADERSIZE_MAX;
+/* magic number + skippable frame length */
+static const size_t ZSTD_skippableHeaderSize = 8;
+
+
+/*-*************************************
+ * Compressed size functions
+ **************************************/
+
+/**
+ * ZSTD_findFrameCompressedSize() - returns the size of a compressed frame
+ * @src:     Source buffer. It should point to the start of a zstd encoded 
frame
+ *           or a skippable frame.
+ * @srcSize: The size of the source buffer. It must be at least as large as the
+ *           size of the frame.
+ *
+ * Return:   The compressed size of the frame pointed to by `src` or an error,
+ *           which can be check with ZSTD_isError().
+ *           Suitable to pass to ZSTD_decompress() or similar functions.
+ */
+size_t ZSTD_findFrameCompressedSize(const void *src, size_t srcSize);
+
+/*-*************************************
+ * Decompressed size functions
+ **************************************/
+/**
+ * ZSTD_getFrameContentSize() - returns the content size in a zstd frame header
+ * @src:     It should point to the start of a zstd encoded frame.
+ * @srcSize: The size of the source buffer. It must be at least as large as the
+ *           frame header. `ZSTD_frameHeaderSize_max` is always large enough.
+ *
+ * Return:   The frame content size stored in the frame header if known.
+ *           `ZSTD_CONTENTSIZE_UNKNOWN` if the content size isn't stored in the
+ *           frame header. `ZSTD_CONTENTSIZE_ERROR` on invalid input.
+ */
+unsigned long long ZSTD_getFrameContentSize(const void *src, size_t srcSize);
+
+/**
+ * ZSTD_findDecompressedSize() - returns decompressed size of a series of 
frames
+ * @src:     It should point to the start of a series of zstd encoded and/or
+ *           skippable frames.
+ * @srcSize: The exact size of the series of frames.
+ *
+ * If any zstd encoded frame in the series doesn't have the frame content size
+ * set, `ZSTD_CONTENTSIZE_UNKNOWN` is returned. But frame content size is 
always
+ * set when using ZSTD_compress(). The decompressed size can be very large.
+ * If the source is untrusted, the decompressed size could be wrong or
+ * intentionally modified. Always ensure the result fits within the
+ * application's authorized limits. ZSTD_findDecompressedSize() handles 
multiple
+ * frames, and so it must traverse the input to read each frame header. This is
+ * efficient as most of the data is skipped, however it does mean that all 
frame
+ * data must be present and valid.
+ *
+ * Return:   Decompressed size of all the data contained in the frames if 
known.
+ *           `ZSTD_CONTENTSIZE_UNKNOWN` if the decompressed size is unknown.
+ *           `ZSTD_CONTENTSIZE_ERROR` if an error occurred.
+ */
+unsigned long long ZSTD_findDecompressedSize(const void *src, size_t srcSize);
+
+/*-*************************************
+ * Advanced compression functions
+ **************************************/
+/**
+ * ZSTD_checkCParams() - ensure parameter values remain within authorized range
+ * @cParams: The zstd compression parameters.
+ *
+ * Return:   Zero or an error, which can be checked using ZSTD_isError().
+ */
+size_t ZSTD_checkCParams(ZSTD_compressionParameters cParams);
+
+/**
+ * ZSTD_adjustCParams() - optimize parameters for a given srcSize and dictSize
+ * @srcSize:  Optionally the estimated source size, or zero if unknown.
+ * @dictSize: Optionally the estimated dictionary size, or zero if unknown.
+ *
+ * Return:    The optimized parameters.
+ */
+ZSTD_compressionParameters ZSTD_adjustCParams(
+       ZSTD_compressionParameters cParams, unsigned long long srcSize,
+       size_t dictSize);
+
+/*--- Advanced decompression functions ---*/
+
+/**
+ * ZSTD_isFrame() - returns true iff the buffer starts with a valid frame
+ * @buffer: The source buffer to check.
+ * @size:   The size of the source buffer, must be at least 4 bytes.
+ *
+ * Return: True iff the buffer starts with a zstd or skippable frame 
identifier.
+ */
+unsigned int ZSTD_isFrame(const void *buffer, size_t size);
+
+/**
+ * ZSTD_getDictID_fromDict() - returns the dictionary id stored in a dictionary
+ * @dict:     The dictionary buffer.
+ * @dictSize: The size of the dictionary buffer.
+ *
+ * Return:    The dictionary id stored within the dictionary or 0 if the
+ *            dictionary is not a zstd dictionary. If it returns 0 the
+ *            dictionary can still be loaded as a content-only dictionary.
+ */
+unsigned int ZSTD_getDictID_fromDict(const void *dict, size_t dictSize);
+
+/**
+ * ZSTD_getDictID_fromDDict() - returns the dictionary id stored in a 
ZSTD_DDict
+ * @ddict: The ddict to find the id of.
+ *
+ * Return: The dictionary id stored within `ddict` or 0 if the dictionary is 
not
+ *         a zstd dictionary. If it returns 0 `ddict` will be loaded as a
+ *         content-only dictionary.
+ */
+unsigned int ZSTD_getDictID_fromDDict(const ZSTD_DDict *ddict);
+
+/**
+ * ZSTD_getDictID_fromFrame() - returns the dictionary id stored in a zstd 
frame
+ * @src:     Source buffer. It must be a zstd encoded frame.
+ * @srcSize: The size of the source buffer. It must be at least as large as the
+ *           frame header. `ZSTD_frameHeaderSize_max` is always large enough.
+ *
+ * Return:   The dictionary id required to decompress the frame stored within
+ *           `src` or 0 if the dictionary id could not be decoded. It can 
return
+ *           0 if the frame does not require a dictionary, the dictionary id
+ *           wasn't stored in the frame, `src` is not a zstd frame, or 
`srcSize`
+ *           is too small.
+ */
+unsigned int ZSTD_getDictID_fromFrame(const void *src, size_t srcSize);
+
+/**
+ * struct ZSTD_frameParams - zstd frame parameters stored in the frame header
+ * @frameContentSize: The frame content size, or 0 if not present.
+ * @windowSize:       The window size, or 0 if the frame is a skippable frame.
+ * @dictID:           The dictionary id, or 0 if not present.
+ * @checksumFlag:     Whether a checksum was used.
+ */
+typedef struct {
+       unsigned long long frameContentSize;
+       unsigned int windowSize;
+       unsigned int dictID;
+       unsigned int checksumFlag;
+} ZSTD_frameParams;
+
+/**
+ * ZSTD_getFrameParams() - extracts parameters from a zstd or skippable frame
+ * @fparamsPtr: On success the frame parameters are written here.
+ * @src:        The source buffer. It must point to a zstd or skippable frame.
+ * @srcSize:    The size of the source buffer. `ZSTD_frameHeaderSize_max` is
+ *              always large enough to succeed.
+ *
+ * Return:      0 on success. If more data is required it returns how many 
bytes
+ *              must be provided to make forward progress. Otherwise it returns
+ *              an error, which can be checked using ZSTD_isError().
+ */
+size_t ZSTD_getFrameParams(ZSTD_frameParams *fparamsPtr, const void *src,
+       size_t srcSize);
+
+/*-*****************************************************************************
+ * Buffer-less and synchronous inner streaming functions
+ *
+ * This is an advanced API, giving full control over buffer management, for
+ * users which need direct control over memory.
+ * But it's also a complex one, with many restrictions (documented below).
+ * Prefer using normal streaming API for an easier experience
+ 
******************************************************************************/
+
+/*-*****************************************************************************
+ * Buffer-less streaming compression (synchronous mode)
+ *
+ * A ZSTD_CCtx object is required to track streaming operations.
+ * Use ZSTD_initCCtx() to initialize a context.
+ * ZSTD_CCtx object can be re-used multiple times within successive compression
+ * operations.
+ *
+ * Start by initializing a context.
+ * Use ZSTD_compressBegin(), or ZSTD_compressBegin_usingDict() for dictionary
+ * compression,
+ * or ZSTD_compressBegin_advanced(), for finer parameter control.
+ * It's also possible to duplicate a reference context which has already been
+ * initialized, using ZSTD_copyCCtx()
+ *
+ * Then, consume your input using ZSTD_compressContinue().
+ * There are some important considerations to keep in mind when using this
+ * advanced function :
+ * - ZSTD_compressContinue() has no internal buffer. It uses externally 
provided
+ *   buffer only.
+ * - Interface is synchronous : input is consumed entirely and produce 1+
+ *   (or more) compressed blocks.
+ * - Caller must ensure there is enough space in `dst` to store compressed data
+ *   under worst case scenario. Worst case evaluation is provided by
+ *   ZSTD_compressBound().
+ *   ZSTD_compressContinue() doesn't guarantee recover after a failed
+ *   compression.
+ * - ZSTD_compressContinue() presumes prior input ***is still accessible and
+ *   unmodified*** (up to maximum distance size, see WindowLog).
+ *   It remembers all previous contiguous blocks, plus one separated memory
+ *   segment (which can itself consists of multiple contiguous blocks)
+ * - ZSTD_compressContinue() detects that prior input has been overwritten when
+ *   `src` buffer overlaps. In which case, it will "discard" the relevant 
memory
+ *   section from its history.
+ *
+ * Finish a frame with ZSTD_compressEnd(), which will write the last block(s)
+ * and optional checksum. It's possible to use srcSize==0, in which case, it
+ * will write a final empty block to end the frame. Without last block mark,
+ * frames will be considered unfinished (corrupted) by decoders.
+ *
+ * `ZSTD_CCtx` object can be re-used (ZSTD_compressBegin()) to compress some 
new
+ * frame.
+ 
******************************************************************************/
+
+/*=====   Buffer-less streaming compression functions  =====*/
+size_t ZSTD_compressBegin(ZSTD_CCtx *cctx, int compressionLevel);
+size_t ZSTD_compressBegin_usingDict(ZSTD_CCtx *cctx, const void *dict,
+       size_t dictSize, int compressionLevel);
+size_t ZSTD_compressBegin_advanced(ZSTD_CCtx *cctx, const void *dict,
+       size_t dictSize, ZSTD_parameters params,
+       unsigned long long pledgedSrcSize);
+size_t ZSTD_copyCCtx(ZSTD_CCtx *cctx, const ZSTD_CCtx *preparedCCtx,
+       unsigned long long pledgedSrcSize);
+size_t ZSTD_compressBegin_usingCDict(ZSTD_CCtx *cctx, const ZSTD_CDict *cdict,
+       unsigned long long pledgedSrcSize);
+size_t ZSTD_compressContinue(ZSTD_CCtx *cctx, void *dst, size_t dstCapacity,
+       const void *src, size_t srcSize);
+size_t ZSTD_compressEnd(ZSTD_CCtx *cctx, void *dst, size_t dstCapacity,
+       const void *src, size_t srcSize);
+
+
+
+/*-*****************************************************************************
+ * Buffer-less streaming decompression (synchronous mode)
+ *
+ * A ZSTD_DCtx object is required to track streaming operations.
+ * Use ZSTD_initDCtx() to initialize a context.
+ * A ZSTD_DCtx object can be re-used multiple times.
+ *
+ * First typical operation is to retrieve frame parameters, using
+ * ZSTD_getFrameParams(). It fills a ZSTD_frameParams structure which provide
+ * important information to correctly decode the frame, such as the minimum
+ * rolling buffer size to allocate to decompress data (`windowSize`), and the
+ * dictionary ID used.
+ * Note: content size is optional, it may not be present. 0 means unknown.
+ * Note that these values could be wrong, either because of data malformation,
+ * or because an attacker is spoofing deliberate false information. As a
+ * consequence, check that values remain within valid application range,
+ * especially `windowSize`, before allocation. Each application can set its own
+ * limit, depending on local restrictions. For extended interoperability, it is
+ * recommended to support at least 8 MB.
+ * Frame parameters are extracted from the beginning of the compressed frame.
+ * Data fragment must be large enough to ensure successful decoding, typically
+ * `ZSTD_frameHeaderSize_max` bytes.
+ * Result: 0: successful decoding, the `ZSTD_frameParams` structure is filled.
+ *        >0: `srcSize` is too small, provide at least this many bytes.
+ *        errorCode, which can be tested using ZSTD_isError().
+ *
+ * Start decompression, with ZSTD_decompressBegin() or
+ * ZSTD_decompressBegin_usingDict(). Alternatively, you can copy a prepared
+ * context, using ZSTD_copyDCtx().
+ *
+ * Then use ZSTD_nextSrcSizeToDecompress() and ZSTD_decompressContinue()
+ * alternatively.
+ * ZSTD_nextSrcSizeToDecompress() tells how many bytes to provide as 'srcSize'
+ * to ZSTD_decompressContinue().
+ * ZSTD_decompressContinue() requires this _exact_ amount of bytes, or it will
+ * fail.
+ *
+ * The result of ZSTD_decompressContinue() is the number of bytes regenerated
+ * within 'dst' (necessarily <= dstCapacity). It can be zero, which is not an
+ * error; it just means ZSTD_decompressContinue() has decoded some metadata
+ * item. It can also be an error code, which can be tested with ZSTD_isError().
+ *
+ * ZSTD_decompressContinue() needs previous data blocks during decompression, 
up
+ * to `windowSize`. They should preferably be located contiguously, prior to
+ * current block. Alternatively, a round buffer of sufficient size is also
+ * possible. Sufficient size is determined by frame parameters.
+ * ZSTD_decompressContinue() is very sensitive to contiguity, if 2 blocks don't
+ * follow each other, make sure that either the compressor breaks contiguity at
+ * the same place, or that previous contiguous segment is large enough to
+ * properly handle maximum back-reference.
+ *
+ * A frame is fully decoded when ZSTD_nextSrcSizeToDecompress() returns zero.
+ * Context can then be reset to start a new decompression.
+ *
+ * Note: it's possible to know if next input to present is a header or a block,
+ * using ZSTD_nextInputType(). This information is not required to properly
+ * decode a frame.
+ *
+ * == Special case: skippable frames ==
+ *
+ * Skippable frames allow integration of user-defined data into a flow of
+ * concatenated frames. Skippable frames will be ignored (skipped) by a
+ * decompressor. The format of skippable frames is as follows:
+ * a) Skippable frame ID - 4 Bytes, Little endian format, any value from
+ *    0x184D2A50 to 0x184D2A5F
+ * b) Frame Size - 4 Bytes, Little endian format, unsigned 32-bits
+ * c) Frame Content - any content (User Data) of length equal to Frame Size
+ * For skippable frames ZSTD_decompressContinue() always returns 0.
+ * For skippable frames ZSTD_getFrameParams() returns fparamsPtr->windowLog==0
+ * what means that a frame is skippable.
+ * Note: If fparamsPtr->frameContentSize==0, it is ambiguous: the frame might
+ *       actually be a zstd encoded frame with no content. For purposes of
+ *       decompression, it is valid in both cases to skip the frame using
+ *       ZSTD_findFrameCompressedSize() to find its size in bytes.
+ * It also returns frame size as fparamsPtr->frameContentSize.
+ 
******************************************************************************/
+
+/*=====   Buffer-less streaming decompression functions  =====*/
+size_t ZSTD_decompressBegin(ZSTD_DCtx *dctx);
+size_t ZSTD_decompressBegin_usingDict(ZSTD_DCtx *dctx, const void *dict,
+       size_t dictSize);
+void   ZSTD_copyDCtx(ZSTD_DCtx *dctx, const ZSTD_DCtx *preparedDCtx);
+size_t ZSTD_nextSrcSizeToDecompress(ZSTD_DCtx *dctx);
+size_t ZSTD_decompressContinue(ZSTD_DCtx *dctx, void *dst, size_t dstCapacity,
+       const void *src, size_t srcSize);
+typedef enum {
+       ZSTDnit_frameHeader,
+       ZSTDnit_blockHeader,
+       ZSTDnit_block,
+       ZSTDnit_lastBlock,
+       ZSTDnit_checksum,
+       ZSTDnit_skippableFrame
+} ZSTD_nextInputType_e;
+ZSTD_nextInputType_e ZSTD_nextInputType(ZSTD_DCtx *dctx);
+
+/*-*****************************************************************************
+ * Block functions
+ *
+ * Block functions produce and decode raw zstd blocks, without frame metadata.
+ * Frame metadata cost is typically ~18 bytes, which can be non-negligible for
+ * very small blocks (< 100 bytes). User will have to take in charge required
+ * information to regenerate data, such as compressed and content sizes.
+ *
+ * A few rules to respect:
+ * - Compressing and decompressing require a context structure
+ *   + Use ZSTD_initCCtx() and ZSTD_initDCtx()
+ * - It is necessary to init context before starting
+ *   + compression : ZSTD_compressBegin()
+ *   + decompression : ZSTD_decompressBegin()
+ *   + variants _usingDict() are also allowed
+ *   + copyCCtx() and copyDCtx() work too
+ * - Block size is limited, it must be <= ZSTD_getBlockSizeMax()
+ *   + If you need to compress more, cut data into multiple blocks
+ *   + Consider using the regular ZSTD_compress() instead, as frame metadata
+ *     costs become negligible when source size is large.
+ * - When a block is considered not compressible enough, ZSTD_compressBlock()
+ *   result will be zero. In which case, nothing is produced into `dst`.
+ *   + User must test for such outcome and deal directly with uncompressed data
+ *   + ZSTD_decompressBlock() doesn't accept uncompressed data as input!!!
+ *   + In case of multiple successive blocks, decoder must be informed of
+ *     uncompressed block existence to follow proper history. Use
+ *     ZSTD_insertBlock() in such a case.
+ 
******************************************************************************/
+
+/* Define for static allocation */
+#define ZSTD_BLOCKSIZE_ABSOLUTEMAX (128 * 1024)
+/*=====   Raw zstd block functions  =====*/
+size_t ZSTD_getBlockSizeMax(ZSTD_CCtx *cctx);
+size_t ZSTD_compressBlock(ZSTD_CCtx *cctx, void *dst, size_t dstCapacity,
+       const void *src, size_t srcSize);
+size_t ZSTD_decompressBlock(ZSTD_DCtx *dctx, void *dst, size_t dstCapacity,
+       const void *src, size_t srcSize);
+size_t ZSTD_insertBlock(ZSTD_DCtx *dctx, const void *blockStart,
+       size_t blockSize);
+
+#endif  /* ZSTD_H */
diff --git a/grub-core/lib/zstd/zstd_common.c b/grub-core/lib/zstd/zstd_common.c
new file mode 100644
index 000000000..a282624ee
--- /dev/null
+++ b/grub-core/lib/zstd/zstd_common.c
@@ -0,0 +1,75 @@
+/**
+ * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of https://github.com/facebook/zstd.
+ * An additional grant of patent rights can be found in the PATENTS file in the
+ * same directory.
+ *
+ * This program is free software; you can redistribute it and/or modify it 
under
+ * the terms of the GNU General Public License version 2 as published by the
+ * Free Software Foundation. This program is dual-licensed; you may select
+ * either version 2 of the GNU General Public License ("GPL") or BSD license
+ * ("BSD").
+ */
+
+/*-*************************************
+*  Dependencies
+***************************************/
+#include "error_private.h"
+#include "zstd_internal.h" /* declaration of ZSTD_isError, ZSTD_getErrorName, 
ZSTD_getErrorCode, ZSTD_getErrorString, ZSTD_versionNumber */
+#include <linux/kernel.h>
+
+/*=**************************************************************
+*  Custom allocator
+****************************************************************/
+
+#define stack_push(stack, size)                                 \
+       ({                                                      \
+               void *const ptr = ZSTD_PTR_ALIGN((stack)->ptr); \
+               (stack)->ptr = (char *)ptr + (size);            \
+               (stack)->ptr <= (stack)->end ? ptr : NULL;      \
+       })
+
+ZSTD_customMem ZSTD_initStack(void *workspace, size_t workspaceSize)
+{
+       ZSTD_customMem stackMem = {ZSTD_stackAlloc, ZSTD_stackFree, workspace};
+       ZSTD_stack *stack = (ZSTD_stack *)workspace;
+       /* Verify preconditions */
+       if (!workspace || workspaceSize < sizeof(ZSTD_stack) || workspace != 
ZSTD_PTR_ALIGN(workspace)) {
+               ZSTD_customMem error = {NULL, NULL, NULL};
+               return error;
+       }
+       /* Initialize the stack */
+       stack->ptr = workspace;
+       stack->end = (char *)workspace + workspaceSize;
+       stack_push(stack, sizeof(ZSTD_stack));
+       return stackMem;
+}
+
+void *ZSTD_stackAllocAll(void *opaque, size_t *size)
+{
+       ZSTD_stack *stack = (ZSTD_stack *)opaque;
+       *size = (BYTE const *)stack->end - (BYTE *)ZSTD_PTR_ALIGN(stack->ptr);
+       return stack_push(stack, *size);
+}
+
+void *ZSTD_stackAlloc(void *opaque, size_t size)
+{
+       ZSTD_stack *stack = (ZSTD_stack *)opaque;
+       return stack_push(stack, size);
+}
+void ZSTD_stackFree(void *opaque, void *address)
+{
+       (void)opaque;
+       (void)address;
+}
+
+void *ZSTD_malloc(size_t size, ZSTD_customMem customMem) { return 
customMem.customAlloc(customMem.opaque, size); }
+
+void ZSTD_free(void *ptr, ZSTD_customMem customMem)
+{
+       if (ptr != NULL)
+               customMem.customFree(customMem.opaque, ptr);
+}
diff --git a/grub-core/lib/zstd/zstd_internal.h 
b/grub-core/lib/zstd/zstd_internal.h
new file mode 100644
index 000000000..1a79fab9e
--- /dev/null
+++ b/grub-core/lib/zstd/zstd_internal.h
@@ -0,0 +1,263 @@
+/**
+ * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of https://github.com/facebook/zstd.
+ * An additional grant of patent rights can be found in the PATENTS file in the
+ * same directory.
+ *
+ * This program is free software; you can redistribute it and/or modify it 
under
+ * the terms of the GNU General Public License version 2 as published by the
+ * Free Software Foundation. This program is dual-licensed; you may select
+ * either version 2 of the GNU General Public License ("GPL") or BSD license
+ * ("BSD").
+ */
+
+#ifndef ZSTD_CCOMMON_H_MODULE
+#define ZSTD_CCOMMON_H_MODULE
+
+/*-*******************************************************
+*  Compiler specifics
+*********************************************************/
+#define FORCE_INLINE static __always_inline
+#define FORCE_NOINLINE static noinline
+
+/*-*************************************
+*  Dependencies
+***************************************/
+#include "error_private.h"
+#include "mem.h"
+#include <linux/compiler.h>
+#include <linux/kernel.h>
+#include <linux/xxhash.h>
+#include <linux/zstd.h>
+
+/*-*************************************
+*  shared macros
+***************************************/
+#define MIN(a, b) ((a) < (b) ? (a) : (b))
+#define MAX(a, b) ((a) > (b) ? (a) : (b))
+#define CHECK_F(f)                       \
+       {                                \
+               size_t const errcod = f; \
+               if (ERR_isError(errcod)) \
+                       return errcod;   \
+       } /* check and Forward error code */
+#define CHECK_E(f, e)                    \
+       {                                \
+               size_t const errcod = f; \
+               if (ERR_isError(errcod)) \
+                       return ERROR(e); \
+       } /* check and send Error code */
+#define ZSTD_STATIC_ASSERT(c)                                   \
+       {                                                       \
+               enum { ZSTD_static_assert = 1 / (int)(!!(c)) }; \
+       }
+
+/*-*************************************
+*  Common constants
+***************************************/
+#define ZSTD_OPT_NUM (1 << 12)
+#define ZSTD_DICT_MAGIC 0xEC30A437 /* v0.7+ */
+
+#define ZSTD_REP_NUM 3               /* number of repcodes */
+#define ZSTD_REP_CHECK (ZSTD_REP_NUM) /* number of repcodes to check by the 
optimal parser */
+#define ZSTD_REP_MOVE (ZSTD_REP_NUM - 1)
+#define ZSTD_REP_MOVE_OPT (ZSTD_REP_NUM)
+static const U32 repStartValue[ZSTD_REP_NUM] = {1, 4, 8};
+
+#define KB *(1 << 10)
+#define MB *(1 << 20)
+#define GB *(1U << 30)
+
+#define BIT7 128
+#define BIT6 64
+#define BIT5 32
+#define BIT4 16
+#define BIT1 2
+#define BIT0 1
+
+#define ZSTD_WINDOWLOG_ABSOLUTEMIN 10
+static const size_t ZSTD_fcs_fieldSize[4] = {0, 2, 4, 8};
+static const size_t ZSTD_did_fieldSize[4] = {0, 1, 2, 4};
+
+#define ZSTD_BLOCKHEADERSIZE 3 /* C standard doesn't allow `static const` 
variable to be init using another `static const` variable */
+static const size_t ZSTD_blockHeaderSize = ZSTD_BLOCKHEADERSIZE;
+typedef enum { bt_raw, bt_rle, bt_compressed, bt_reserved } blockType_e;
+
+#define MIN_SEQUENCES_SIZE 1                                                   
                  /* nbSeq==0 */
+#define MIN_CBLOCK_SIZE (1 /*litCSize*/ + 1 /* RLE or RAW */ + 
MIN_SEQUENCES_SIZE /* nbSeq==0 */) /* for a non-null block */
+
+#define HufLog 12
+typedef enum { set_basic, set_rle, set_compressed, set_repeat } 
symbolEncodingType_e;
+
+#define LONGNBSEQ 0x7F00
+
+#define MINMATCH 3
+#define EQUAL_READ32 4
+
+#define Litbits 8
+#define MaxLit ((1 << Litbits) - 1)
+#define MaxML 52
+#define MaxLL 35
+#define MaxOff 28
+#define MaxSeq MAX(MaxLL, MaxML) /* Assumption : MaxOff < MaxLL,MaxML */
+#define MLFSELog 9
+#define LLFSELog 9
+#define OffFSELog 8
+
+static const U32 LL_bits[MaxLL + 1] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
0, 0, 0, 1, 1, 1, 1, 2, 2, 3, 3, 4, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16};
+static const S16 LL_defaultNorm[MaxLL + 1] = {4, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 
2, 2, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 2, 1, 1, 1, 1, 1, -1, -1, -1, -1};
+#define LL_DEFAULTNORMLOG 6 /* for static allocation */
+static const U32 LL_defaultNormLog = LL_DEFAULTNORMLOG;
+
+static const U32 ML_bits[MaxML + 1] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
0, 0, 0, 0, 0, 0, 0,  0,  0,  0,  0,  0,  0, 0,
+                                      0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 3, 3, 
4, 4, 5, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16};
+static const S16 ML_defaultNorm[MaxML + 1] = {1, 4, 3, 2, 2, 2, 2, 2, 2, 1, 1, 
1, 1, 1, 1, 1, 1, 1, 1, 1,  1,  1,  1,  1,  1,  1, 1,
+                                             1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 
1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1};
+#define ML_DEFAULTNORMLOG 6 /* for static allocation */
+static const U32 ML_defaultNormLog = ML_DEFAULTNORMLOG;
+
+static const S16 OF_defaultNorm[MaxOff + 1] = {1, 1, 1, 1, 1, 1, 2, 2, 2, 1, 
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1};
+#define OF_DEFAULTNORMLOG 5 /* for static allocation */
+static const U32 OF_defaultNormLog = OF_DEFAULTNORMLOG;
+
+/*-*******************************************
+*  Shared functions to include for inlining
+*********************************************/
+ZSTD_STATIC void ZSTD_copy8(void *dst, const void *src) {
+       memcpy(dst, src, 8);
+}
+/*! ZSTD_wildcopy() :
+*   custom version of memcpy(), can copy up to 7 bytes too many (8 bytes if 
length==0) */
+#define WILDCOPY_OVERLENGTH 8
+ZSTD_STATIC void ZSTD_wildcopy(void *dst, const void *src, ptrdiff_t length)
+{
+       const BYTE* ip = (const BYTE*)src;
+       BYTE* op = (BYTE*)dst;
+       BYTE* const oend = op + length;
+       /* Work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81388.
+        * Avoid the bad case where the loop only runs once by handling the
+        * special case separately. This doesn't trigger the bug because it
+        * doesn't involve pointer/integer overflow.
+        */
+       if (length <= 8)
+               return ZSTD_copy8(dst, src);
+       do {
+               ZSTD_copy8(op, ip);
+               op += 8;
+               ip += 8;
+       } while (op < oend);
+}
+
+/*-*******************************************
+*  Private interfaces
+*********************************************/
+typedef struct ZSTD_stats_s ZSTD_stats_t;
+
+typedef struct {
+       U32 off;
+       U32 len;
+} ZSTD_match_t;
+
+typedef struct {
+       U32 price;
+       U32 off;
+       U32 mlen;
+       U32 litlen;
+       U32 rep[ZSTD_REP_NUM];
+} ZSTD_optimal_t;
+
+typedef struct seqDef_s {
+       U32 offset;
+       U16 litLength;
+       U16 matchLength;
+} seqDef;
+
+typedef struct {
+       seqDef *sequencesStart;
+       seqDef *sequences;
+       BYTE *litStart;
+       BYTE *lit;
+       BYTE *llCode;
+       BYTE *mlCode;
+       BYTE *ofCode;
+       U32 longLengthID; /* 0 == no longLength; 1 == Lit.longLength; 2 == 
Match.longLength; */
+       U32 longLengthPos;
+       /* opt */
+       ZSTD_optimal_t *priceTable;
+       ZSTD_match_t *matchTable;
+       U32 *matchLengthFreq;
+       U32 *litLengthFreq;
+       U32 *litFreq;
+       U32 *offCodeFreq;
+       U32 matchLengthSum;
+       U32 matchSum;
+       U32 litLengthSum;
+       U32 litSum;
+       U32 offCodeSum;
+       U32 log2matchLengthSum;
+       U32 log2matchSum;
+       U32 log2litLengthSum;
+       U32 log2litSum;
+       U32 log2offCodeSum;
+       U32 factor;
+       U32 staticPrices;
+       U32 cachedPrice;
+       U32 cachedLitLength;
+       const BYTE *cachedLiterals;
+} seqStore_t;
+
+const seqStore_t *ZSTD_getSeqStore(const ZSTD_CCtx *ctx);
+void ZSTD_seqToCodes(const seqStore_t *seqStorePtr);
+int ZSTD_isSkipFrame(ZSTD_DCtx *dctx);
+
+/*= Custom memory allocation functions */
+typedef void *(*ZSTD_allocFunction)(void *opaque, size_t size);
+typedef void (*ZSTD_freeFunction)(void *opaque, void *address);
+typedef struct {
+       ZSTD_allocFunction customAlloc;
+       ZSTD_freeFunction customFree;
+       void *opaque;
+} ZSTD_customMem;
+
+void *ZSTD_malloc(size_t size, ZSTD_customMem customMem);
+void ZSTD_free(void *ptr, ZSTD_customMem customMem);
+
+/*====== stack allocation  ======*/
+
+typedef struct {
+       void *ptr;
+       const void *end;
+} ZSTD_stack;
+
+#define ZSTD_ALIGN(x) ALIGN(x, sizeof(size_t))
+#define ZSTD_PTR_ALIGN(p) PTR_ALIGN(p, sizeof(size_t))
+
+ZSTD_customMem ZSTD_initStack(void *workspace, size_t workspaceSize);
+
+void *ZSTD_stackAllocAll(void *opaque, size_t *size);
+void *ZSTD_stackAlloc(void *opaque, size_t size);
+void ZSTD_stackFree(void *opaque, void *address);
+
+/*======  common function  ======*/
+
+ZSTD_STATIC U32 ZSTD_highbit32(U32 val) { return 31 - __builtin_clz(val); }
+
+/* hidden functions */
+
+/* ZSTD_invalidateRepCodes() :
+ * ensures next compression will not use repcodes from previous block.
+ * Note : only works with regular variant;
+ *        do not use with extDict variant ! */
+void ZSTD_invalidateRepCodes(ZSTD_CCtx *cctx);
+
+size_t ZSTD_freeCCtx(ZSTD_CCtx *cctx);
+size_t ZSTD_freeDCtx(ZSTD_DCtx *dctx);
+size_t ZSTD_freeCDict(ZSTD_CDict *cdict);
+size_t ZSTD_freeDDict(ZSTD_DDict *cdict);
+size_t ZSTD_freeCStream(ZSTD_CStream *zcs);
+size_t ZSTD_freeDStream(ZSTD_DStream *zds);
+
+#endif /* ZSTD_CCOMMON_H_MODULE */
--
2.16.2



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