qemu/qdict.c

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/*
* QDict data type.
*
* Copyright (C) 2009 Red Hat Inc.
*
* Authors:
* Luiz Capitulino <lcapitulino@redhat.com>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*/
#include "qint.h"
#include "qdict.h"
#include "qstring.h"
#include "qobject.h"
#include "sys-queue.h"
#include "qemu-common.h"
static void qdict_destroy_obj(QObject *obj);
static const QType qdict_type = {
.code = QTYPE_QDICT,
.destroy = qdict_destroy_obj,
};
/**
* qdict_new(): Create a new QDict
*
* Return strong reference.
*/
QDict *qdict_new(void)
{
QDict *qdict;
qdict = qemu_mallocz(sizeof(*qdict));
QOBJECT_INIT(qdict, &qdict_type);
return qdict;
}
/**
* qobject_to_qdict(): Convert a QObject into a QDict
*/
QDict *qobject_to_qdict(const QObject *obj)
{
if (qobject_type(obj) != QTYPE_QDICT)
return NULL;
return container_of(obj, QDict, base);
}
/**
* 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);
}
/**
* alloc_entry(): allocate a new QDictEntry
*/
static QDictEntry *alloc_entry(const char *key, QObject *value)
{
QDictEntry *entry;
entry = qemu_mallocz(sizeof(*entry));
entry->key = qemu_strdup(key);
entry->value = value;
return entry;
}
/**
* qdict_find(): List lookup function
*/
static QDictEntry *qdict_find(const QDict *qdict,
const char *key, unsigned int hash)
{
QDictEntry *entry;
LIST_FOREACH(entry, &qdict->table[hash], next)
if (!strcmp(entry->key, key))
return entry;
return NULL;
}
/**
* qdict_put_obj(): Put a new QObject into the dictionary
*
* Insert the pair 'key:value' into 'qdict', if 'key' already exists
* its 'value' will be replaced.
*
* This is done by freeing the reference to the stored QObject and
* storing the new one in the same entry.
*
* NOTE: ownership of 'value' is transferred to the QDict
*/
void qdict_put_obj(QDict *qdict, const char *key, QObject *value)
{
unsigned int hash;
QDictEntry *entry;
hash = tdb_hash(key) % QDICT_HASH_SIZE;
entry = qdict_find(qdict, key, hash);
if (entry) {
/* replace key's value */
qobject_decref(entry->value);
entry->value = value;
} else {
/* allocate a new entry */
entry = alloc_entry(key, value);
LIST_INSERT_HEAD(&qdict->table[hash], entry, next);
}
qdict->size++;
}
/**
* qdict_get(): Lookup for a given 'key'
*
* Return a weak reference to the QObject associated with 'key' if
* 'key' is present in the dictionary, NULL otherwise.
*/
QObject *qdict_get(const QDict *qdict, const char *key)
{
QDictEntry *entry;
entry = qdict_find(qdict, key, tdb_hash(key) % QDICT_HASH_SIZE);
return (entry == NULL ? NULL : entry->value);
}
/**
* qdict_haskey(): Check if 'key' exists
*
* Return 1 if 'key' exists in the dict, 0 otherwise
*/
int qdict_haskey(const QDict *qdict, const char *key)
{
unsigned int hash = tdb_hash(key) % QDICT_HASH_SIZE;
return (qdict_find(qdict, key, hash) == NULL ? 0 : 1);
}
/**
* qdict_size(): Return the size of the dictionary
*/
size_t qdict_size(const QDict *qdict)
{
return qdict->size;
}
/**
* qdict_get_obj(): Get a QObject of a specific type
*/
static QObject *qdict_get_obj(const QDict *qdict, const char *key,
qtype_code type)
{
QObject *obj;
obj = qdict_get(qdict, key);
assert(obj != NULL);
assert(qobject_type(obj) == type);
return obj;
}
/**
* qdict_get_int(): Get an integer mapped by 'key'
*
* This function assumes that 'key' exists and it stores a
* QInt object.
*
* Return integer mapped by 'key'.
*/
int64_t qdict_get_int(const QDict *qdict, const char *key)
{
QObject *obj = qdict_get_obj(qdict, key, QTYPE_QINT);
return qint_get_int(qobject_to_qint(obj));
}
/**
* qdict_get_str(): Get a pointer to the stored string mapped
* by 'key'
*
* This function assumes that 'key' exists and it stores a
* QString object.
*
* Return pointer to the string mapped by 'key'.
*/
const char *qdict_get_str(const QDict *qdict, const char *key)
{
QObject *obj = qdict_get_obj(qdict, key, QTYPE_QSTRING);
return qstring_get_str(qobject_to_qstring(obj));
}
/**
* qdict_get_try_int(): Try to get integer mapped by 'key'
*
* Return integer mapped by 'key', if it is not present in
* the dictionary or if the stored object is not of QInt type
* 'err_value' will be returned.
*/
int64_t qdict_get_try_int(const QDict *qdict, const char *key,
int64_t err_value)
{
QObject *obj;
obj = qdict_get(qdict, key);
if (!obj || qobject_type(obj) != QTYPE_QINT)
return err_value;
return qint_get_int(qobject_to_qint(obj));
}
/**
* qdict_get_try_str(): Try to get a pointer to the stored string
* mapped by 'key'
*
* Return a pointer to the string mapped by 'key', if it is not present
* in the dictionary or if the stored object is not of QString type
* NULL will be returned.
*/
const char *qdict_get_try_str(const QDict *qdict, const char *key)
{
QObject *obj;
obj = qdict_get(qdict, key);
if (!obj || qobject_type(obj) != QTYPE_QSTRING)
return NULL;
return qstring_get_str(qobject_to_qstring(obj));
}
/**
* qentry_destroy(): Free all the memory allocated by a QDictEntry
*/
static void qentry_destroy(QDictEntry *e)
{
assert(e != NULL);
assert(e->key != NULL);
assert(e->value != NULL);
qobject_decref(e->value);
qemu_free(e->key);
qemu_free(e);
}
/**
* qdict_del(): Delete a 'key:value' pair from the dictionary
*
* This will destroy all data allocated by this entry.
*/
void qdict_del(QDict *qdict, const char *key)
{
QDictEntry *entry;
entry = qdict_find(qdict, key, tdb_hash(key) % QDICT_HASH_SIZE);
if (entry) {
LIST_REMOVE(entry, next);
qentry_destroy(entry);
qdict->size--;
}
}
/**
* qdict_destroy_obj(): Free all the memory allocated by a QDict
*/
static void qdict_destroy_obj(QObject *obj)
{
int i;
QDict *qdict;
assert(obj != NULL);
qdict = qobject_to_qdict(obj);
for (i = 0; i < QDICT_HASH_SIZE; i++) {
QDictEntry *entry = LIST_FIRST(&qdict->table[i]);
while (entry) {
QDictEntry *tmp = LIST_NEXT(entry, next);
LIST_REMOVE(entry, next);
qentry_destroy(entry);
entry = tmp;
}
}
qemu_free(qdict);
}