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[Qemu-devel] [PATCH 1/6] qemu-char: Convert MemCharDriver to circular bu
From: |
Lei Li |
Subject: |
[Qemu-devel] [PATCH 1/6] qemu-char: Convert MemCharDriver to circular buffer |
Date: |
Thu, 23 Aug 2012 13:14:21 +0800 |
Signed-off-by: Lei Li <address@hidden>
---
qemu-char.c | 96 +++++++++++++++++++++++++++++++++++++++++++++++-----------
qemu-char.h | 2 +-
2 files changed, 78 insertions(+), 20 deletions(-)
diff --git a/qemu-char.c b/qemu-char.c
index 398baf1..b21b93a 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -2528,38 +2528,96 @@ static CharDriverState *qemu_chr_open_socket(QemuOpts
*opts)
/***********************************************************/
/* Memory chardev */
typedef struct {
- size_t outbuf_size;
- size_t outbuf_capacity;
- uint8_t *outbuf;
+ size_t cbuf_capacity;
+ size_t cbuf_in;
+ size_t cbuf_out;
+ size_t cbuf_count;
+ uint8_t *cbuf;
} MemoryDriver;
+static int mem_chr_is_empty(CharDriverState *chr)
+{
+ MemoryDriver *d = chr->opaque;
+
+ return d->cbuf_count == 0;
+}
+
+static int mem_chr_is_full(CharDriverState *chr)
+{
+ MemoryDriver *d = chr->opaque;
+
+ return d->cbuf_count == d->cbuf_capacity;
+}
+
static int mem_chr_write(CharDriverState *chr, const uint8_t *buf, int len)
{
MemoryDriver *d = chr->opaque;
+ int left;
- /* TODO: the QString implementation has the same code, we should
- * introduce a generic way to do this in cutils.c */
- if (d->outbuf_capacity < d->outbuf_size + len) {
- /* grow outbuf */
- d->outbuf_capacity += len;
- d->outbuf_capacity *= 2;
- d->outbuf = g_realloc(d->outbuf, d->outbuf_capacity);
+ if (d->cbuf_capacity < len) {
+ return -1;
}
- memcpy(d->outbuf + d->outbuf_size, buf, len);
- d->outbuf_size += len;
+ left = d->cbuf_capacity - d->cbuf_count % d->cbuf_capacity;
+
+ /* Some of cbuf need to be overwrited */
+ if (left < len) {
+ memcpy(d->cbuf + d->cbuf_in, buf, left);
+ memcpy(d->cbuf + d->cbuf_out, buf + left, len - left);
+ d->cbuf_out = (d->cbuf_out + len - left) % d->cbuf_capacity;
+ d->cbuf_count = d->cbuf_count + left;
+ } else {
+ /* Completely overwrite */
+ if (mem_chr_is_full(chr)) {
+ d->cbuf_out = (d->cbuf_out + len) % d->cbuf_capacity;
+ } else {
+ /* Enough cbuf to write */
+ d->cbuf_count += len;
+ }
+ memcpy(d->cbuf + d->cbuf_in, buf, len);
+ }
+
+ d->cbuf_in = (d->cbuf_in + len) % d->cbuf_capacity;
return len;
}
-void qemu_chr_init_mem(CharDriverState *chr)
+static void mem_chr_read(CharDriverState *chr, uint8_t *buf, int len)
+{
+ MemoryDriver *d = chr->opaque;
+ int left;
+
+ if (mem_chr_is_empty(chr)) {
+ return;
+ }
+
+ left = d->cbuf_capacity - d->cbuf_count % d->cbuf_capacity;
+
+ if (d->cbuf_capacity < len) {
+ len = d->cbuf_capacity;
+ }
+
+ if (left < len) {
+ memcpy(buf, d->cbuf + d->cbuf_out, left);
+ memcpy(buf + left, d->cbuf + d->cbuf_out + left, len - left);
+ } else {
+ memcpy(buf, d->cbuf + d->cbuf_out, len);
+ }
+
+ d->cbuf_out = (d->cbuf_out + len) % d->cbuf_capacity;
+ d->cbuf_count -= len;
+}
+
+void qemu_chr_init_mem(CharDriverState *chr, size_t size)
{
MemoryDriver *d;
d = g_malloc(sizeof(*d));
- d->outbuf_size = 0;
- d->outbuf_capacity = 4096;
- d->outbuf = g_malloc0(d->outbuf_capacity);
+ d->cbuf_capacity = size;
+ d->cbuf_in = 0;
+ d->cbuf_out = 0;
+ d->cbuf_count = 0;
+ d->cbuf = g_malloc0(d->cbuf_capacity);
memset(chr, 0, sizeof(*chr));
chr->opaque = d;
@@ -2569,7 +2627,7 @@ void qemu_chr_init_mem(CharDriverState *chr)
QString *qemu_chr_mem_to_qs(CharDriverState *chr)
{
MemoryDriver *d = chr->opaque;
- return qstring_from_substr((char *) d->outbuf, 0, d->outbuf_size - 1);
+ return qstring_from_substr((char *) d->cbuf, 0, d->cbuf_count - 1);
}
/* NOTE: this driver can not be closed with qemu_chr_delete()! */
@@ -2577,7 +2635,7 @@ void qemu_chr_close_mem(CharDriverState *chr)
{
MemoryDriver *d = chr->opaque;
- g_free(d->outbuf);
+ g_free(d->cbuf);
g_free(chr->opaque);
chr->opaque = NULL;
chr->chr_write = NULL;
@@ -2586,7 +2644,7 @@ void qemu_chr_close_mem(CharDriverState *chr)
size_t qemu_chr_mem_osize(const CharDriverState *chr)
{
const MemoryDriver *d = chr->opaque;
- return d->outbuf_size;
+ return d->cbuf_count;
}
QemuOpts *qemu_chr_parse_compat(const char *label, const char *filename)
diff --git a/qemu-char.h b/qemu-char.h
index 486644b..d8d90cc 100644
--- a/qemu-char.h
+++ b/qemu-char.h
@@ -243,7 +243,7 @@ CharDriverState *qemu_chr_open_eventfd(int eventfd);
extern int term_escape_char;
/* memory chardev */
-void qemu_chr_init_mem(CharDriverState *chr);
+void qemu_chr_init_mem(CharDriverState *chr, size_t size);
void qemu_chr_close_mem(CharDriverState *chr);
QString *qemu_chr_mem_to_qs(CharDriverState *chr);
size_t qemu_chr_mem_osize(const CharDriverState *chr);
--
1.7.7.6