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[Qemu-devel] [PATCH 01/25] Introduce QEMU dictionary data type
From: |
Luiz Capitulino |
Subject: |
[Qemu-devel] [PATCH 01/25] Introduce QEMU dictionary data type |
Date: |
Mon, 3 Aug 2009 13:56:58 -0300 |
A dictionary is a high-level data type used to store a collection of
values, where a unique key is associated with one value. Usually, the
notation 'key:value' is used to denote this relationship.
This commit adds the qdict module, which implements a dictionary for
QEMU and exports the following functions:
- qdict_new() Create a new dictionary
- qdict_add() Add a new 'key:value' pair
- qdict_get() Get the 'value' of a given 'key'
- qdict_exists() Check if a given 'key' exists
- qdict_del() Delete a 'key:value' pair
- qdict_destroy() Destroy the dictionary
- qdict_size() Return the size of the dictionary
qdict module uses a chained hash table, whose hash function comes from
module-init-tools program.
Signed-off-by: Luiz Capitulino <address@hidden>
---
Makefile | 1 +
qdict.c | 183 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
qdict.h | 34 ++++++++++++
3 files changed, 218 insertions(+), 0 deletions(-)
create mode 100644 qdict.c
create mode 100644 qdict.h
diff --git a/Makefile b/Makefile
index d3f999e..41c669f 100644
--- a/Makefile
+++ b/Makefile
@@ -104,6 +104,7 @@ obj-y += buffered_file.o migration.o migration-tcp.o net.o
qemu-sockets.o
obj-y += qemu-char.o aio.o net-checksum.o savevm.o
obj-y += msmouse.o ps2.o
obj-y += qdev.o qdev-properties.o ssi.o
+obj-y += qdict.o
obj-$(CONFIG_BRLAPI) += baum.o
diff --git a/qdict.c b/qdict.c
new file mode 100644
index 0000000..8f911b3
--- /dev/null
+++ b/qdict.c
@@ -0,0 +1,183 @@
+/*
+ * QEMU dictionary data type.
+ *
+ * Copyright (C) 2009 Red Hat Inc.
+ *
+ * Authors:
+ * Luiz Capitulino <address@hidden>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2. See
+ * the COPYING file in the top-level directory.
+ */
+
+#include "qdict.h"
+#include "qemu-common.h"
+
+/**
+ * qdict_new(): Create a new dictionary data-type
+ */
+QDict *qdict_new(void)
+{
+ return qemu_mallocz(sizeof(QDict));
+}
+
+/**
+ * tdb_hash(): based on the hash agorithm from gdbm, via tdb
+ * (from module-init-tools)
+ */
+static unsigned int tdb_hash(const char *name)
+{
+ unsigned value; /* Used to compute the hash value. */
+ unsigned i; /* Used to cycle through random values. */
+
+ /* Set the initial value from the key size. */
+ for (value = 0x238F13AF * strlen(name), i=0; name[i]; i++)
+ value = (value + (((const unsigned char *)name)[i] << (i*5 % 24)));
+
+ return (1103515243 * value + 12345);
+}
+
+/**
+ * qdict_find(): Low-level lookup function
+ */
+static void *qdict_find(const QDict *qdict,
+ const char *key, unsigned int hash)
+{
+ QDictEntry *e;
+
+ for (e = qdict->table[hash]; e; e = e->next)
+ if (!strcmp(e->key, key))
+ return e->value;
+ return NULL;
+}
+
+/**
+ * qdict_get(): Lookup for a given 'key'
+ *
+ * return corresponding 'value' or NULL if 'key' doesn't exist.
+ */
+void *qdict_get(const QDict *qdict, const char *key)
+{
+ assert(qdict != NULL);
+ assert(key != NULL);
+ return qdict_find(qdict, key, tdb_hash(key) % QDICT_HASH_SIZE);
+}
+
+/**
+ * qdict_exists(): Check if 'key' exists
+ *
+ * return 1 if 'key' exists in the dict, 0 otherwise
+ */
+int qdict_exists(const QDict *qdict, const char *key)
+{
+ QDictEntry *e;
+
+ assert(qdict != NULL);
+ assert(key != NULL);
+
+ for (e = qdict->table[tdb_hash(key) % QDICT_HASH_SIZE]; e; e = e->next)
+ if (!strcmp(e->key, key))
+ return 1;
+ return 0;
+}
+
+/**
+ * alloc_entry(): allocate a new QDictEntry
+ */
+static QDictEntry *alloc_entry(const char *key, void *value)
+{
+ QDictEntry *entry;
+
+ entry = qemu_malloc(sizeof(*entry));
+ entry->key = qemu_strdup(key);
+ entry->value = value;
+ entry->next = NULL;
+
+ return entry;
+}
+
+/**
+ * qdict_add(): Add a new value into the dictionary
+ *
+ * Add the pair 'key:value' into qdict. Does nothing if 'key' already
+ * exist.
+ */
+void qdict_add(QDict *qdict, const char *key, void *value)
+{
+ unsigned int hash;
+ QDictEntry *entry;
+
+ assert(qdict != NULL);
+ assert(key != NULL);
+
+ hash = tdb_hash(key) % QDICT_HASH_SIZE;
+ if (qdict_find(qdict, key, hash)) {
+ /* Don't add again if it's already there */
+ return;
+ }
+
+ entry = alloc_entry(key, value);
+ entry->next = qdict->table[hash];
+ qdict->table[hash] = entry;
+ qdict->size++;
+}
+
+/**
+ * qdict_del(): Delete a given 'key' from the dictionary
+ *
+ * This will destroy all data allocated by 'key', except 'value'
+ * which is returned.
+ */
+void *qdict_del(QDict *qdict, const char *key)
+{
+ unsigned int hash;
+ QDictEntry *e, *prev;
+
+ assert(qdict != NULL);
+ assert(key != NULL);
+
+ prev = NULL;
+ hash = tdb_hash(key) % QDICT_HASH_SIZE;
+ for (e = qdict->table[hash]; e; e = e->next) {
+ if (!strcmp(e->key, key)) {
+ void *value = e->value;
+ if (!prev)
+ qdict->table[hash] = e->next;
+ else
+ prev->next = e->next;
+ qemu_free(e->key);
+ qemu_free(e);
+ qdict->size--;
+ return value;
+ }
+
+ prev = e;
+ }
+
+ return NULL;
+}
+
+/**
+ * qdict_destroy(): Destroy given 'qdict'
+ *
+ * This will destroy all data allocated by 'qdict', but added
+ * values must be freed by the caller.
+ */
+void qdict_destroy(QDict *qdict)
+{
+ int i;
+
+ assert(qdict != NULL);
+
+ for (i = 0; i < QDICT_HASH_SIZE; i++) {
+ QDictEntry *e = qdict->table[i];
+ while (e) {
+ QDictEntry *tmp = e->next;
+ qemu_free(e->key);
+ qemu_free(e);
+ e = tmp;
+ }
+ }
+
+ qemu_free(qdict);
+}
diff --git a/qdict.h b/qdict.h
new file mode 100644
index 0000000..89401ed
--- /dev/null
+++ b/qdict.h
@@ -0,0 +1,34 @@
+#ifndef QDICT_H
+#define QDICT_H
+
+#include <stddef.h>
+
+#define QDICT_HASH_SIZE 512
+
+typedef struct QDictEntry {
+ struct QDictEntry *next;
+ char *key;
+ void *value;
+} QDictEntry;
+
+typedef struct QDict {
+ size_t size;
+ QDictEntry *table[QDICT_HASH_SIZE];
+} QDict;
+
+/**
+ * qdict_size(): return the size of the dictionary
+ */
+static inline size_t qdict_size(const QDict *qdict)
+{
+ return qdict->size;
+}
+
+QDict *qdict_new(void);
+void qdict_add(QDict *qdict, const char *key, void *value);
+void *qdict_get(const QDict *qdict, const char *key);
+int qdict_exists(const QDict *qdict, const char *key);
+void *qdict_del(QDict *qdict, const char *key);
+void qdict_destroy(QDict *qdict);
+
+#endif /* QDICT_H */
--
1.6.4.rc3.12.gdf73a
- [Qemu-devel] [PATCH v1 00/25] Monitor handlers new structure phase 1, Luiz Capitulino, 2009/08/03
- [Qemu-devel] [PATCH 01/25] Introduce QEMU dictionary data type,
Luiz Capitulino <=
- [Qemu-devel] [PATCH 02/25] net: Fix do_set_link() return type, Luiz Capitulino, 2009/08/03
- [Qemu-devel] [PATCH 03/25] Add wrappers to functions used by the Monitor, Luiz Capitulino, 2009/08/03
- [Qemu-devel] [PATCH 04/25] monitor: Document missing supported argument types, Luiz Capitulino, 2009/08/03
- [Qemu-devel] [PATCH 05/25] monitor: New format for handlers argument types, Luiz Capitulino, 2009/08/03
- [Qemu-devel] [PATCH 06/25] monitor: Setup a dictionary with handler arguments, Luiz Capitulino, 2009/08/03
- [Qemu-devel] [PATCH 07/25] monitor: Export qdict.h header, Luiz Capitulino, 2009/08/03
- [Qemu-devel] [PATCH 08/25] monitor: New GET_TLONG and GET_TPHYSADDR macros, Luiz Capitulino, 2009/08/03
- [Qemu-devel] [PATCH 09/25] monitor: Port handler_0 to use the dictionary, Luiz Capitulino, 2009/08/03