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[qemu.git] / qdict.c
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1 /*
2 * QDict data type.
4 * Copyright (C) 2009 Red Hat Inc.
6 * Authors:
7 * Luiz Capitulino <lcapitulino@redhat.com>
9 * This work is licensed under the terms of the GNU GPL, version 2. See
10 * the COPYING file in the top-level directory.
13 #include "qint.h"
14 #include "qdict.h"
15 #include "qstring.h"
16 #include "qobject.h"
17 #include "sys-queue.h"
18 #include "qemu-common.h"
20 static void qdict_destroy_obj(QObject *obj);
22 static const QType qdict_type = {
23 .code = QTYPE_QDICT,
24 .destroy = qdict_destroy_obj,
27 /**
28 * qdict_new(): Create a new QDict
30 * Return strong reference.
32 QDict *qdict_new(void)
34 QDict *qdict;
36 qdict = qemu_mallocz(sizeof(*qdict));
37 QOBJECT_INIT(qdict, &qdict_type);
39 return qdict;
42 /**
43 * qobject_to_qdict(): Convert a QObject into a QDict
45 QDict *qobject_to_qdict(const QObject *obj)
47 if (qobject_type(obj) != QTYPE_QDICT)
48 return NULL;
50 return container_of(obj, QDict, base);
53 /**
54 * tdb_hash(): based on the hash agorithm from gdbm, via tdb
55 * (from module-init-tools)
57 static unsigned int tdb_hash(const char *name)
59 unsigned value; /* Used to compute the hash value. */
60 unsigned i; /* Used to cycle through random values. */
62 /* Set the initial value from the key size. */
63 for (value = 0x238F13AF * strlen(name), i=0; name[i]; i++)
64 value = (value + (((const unsigned char *)name)[i] << (i*5 % 24)));
66 return (1103515243 * value + 12345);
69 /**
70 * alloc_entry(): allocate a new QDictEntry
72 static QDictEntry *alloc_entry(const char *key, QObject *value)
74 QDictEntry *entry;
76 entry = qemu_mallocz(sizeof(*entry));
77 entry->key = qemu_strdup(key);
78 entry->value = value;
80 return entry;
83 /**
84 * qdict_find(): List lookup function
86 static QDictEntry *qdict_find(const QDict *qdict,
87 const char *key, unsigned int hash)
89 QDictEntry *entry;
91 LIST_FOREACH(entry, &qdict->table[hash], next)
92 if (!strcmp(entry->key, key))
93 return entry;
95 return NULL;
98 /**
99 * qdict_put_obj(): Put a new QObject into the dictionary
101 * Insert the pair 'key:value' into 'qdict', if 'key' already exists
102 * its 'value' will be replaced.
104 * This is done by freeing the reference to the stored QObject and
105 * storing the new one in the same entry.
107 * NOTE: ownership of 'value' is transferred to the QDict
109 void qdict_put_obj(QDict *qdict, const char *key, QObject *value)
111 unsigned int hash;
112 QDictEntry *entry;
114 hash = tdb_hash(key) % QDICT_HASH_SIZE;
115 entry = qdict_find(qdict, key, hash);
116 if (entry) {
117 /* replace key's value */
118 qobject_decref(entry->value);
119 entry->value = value;
120 } else {
121 /* allocate a new entry */
122 entry = alloc_entry(key, value);
123 LIST_INSERT_HEAD(&qdict->table[hash], entry, next);
126 qdict->size++;
130 * qdict_get(): Lookup for a given 'key'
132 * Return a weak reference to the QObject associated with 'key' if
133 * 'key' is present in the dictionary, NULL otherwise.
135 QObject *qdict_get(const QDict *qdict, const char *key)
137 QDictEntry *entry;
139 entry = qdict_find(qdict, key, tdb_hash(key) % QDICT_HASH_SIZE);
140 return (entry == NULL ? NULL : entry->value);
144 * qdict_haskey(): Check if 'key' exists
146 * Return 1 if 'key' exists in the dict, 0 otherwise
148 int qdict_haskey(const QDict *qdict, const char *key)
150 unsigned int hash = tdb_hash(key) % QDICT_HASH_SIZE;
151 return (qdict_find(qdict, key, hash) == NULL ? 0 : 1);
155 * qdict_size(): Return the size of the dictionary
157 size_t qdict_size(const QDict *qdict)
159 return qdict->size;
163 * qdict_get_obj(): Get a QObject of a specific type
165 static QObject *qdict_get_obj(const QDict *qdict, const char *key,
166 qtype_code type)
168 QObject *obj;
170 obj = qdict_get(qdict, key);
171 assert(obj != NULL);
172 assert(qobject_type(obj) == type);
174 return obj;
178 * qdict_get_int(): Get an integer mapped by 'key'
180 * This function assumes that 'key' exists and it stores a
181 * QInt object.
183 * Return integer mapped by 'key'.
185 int64_t qdict_get_int(const QDict *qdict, const char *key)
187 QObject *obj = qdict_get_obj(qdict, key, QTYPE_QINT);
188 return qint_get_int(qobject_to_qint(obj));
192 * qdict_get_str(): Get a pointer to the stored string mapped
193 * by 'key'
195 * This function assumes that 'key' exists and it stores a
196 * QString object.
198 * Return pointer to the string mapped by 'key'.
200 const char *qdict_get_str(const QDict *qdict, const char *key)
202 QObject *obj = qdict_get_obj(qdict, key, QTYPE_QSTRING);
203 return qstring_get_str(qobject_to_qstring(obj));
207 * qdict_get_try_int(): Try to get integer mapped by 'key'
209 * Return integer mapped by 'key', if it is not present in
210 * the dictionary or if the stored object is not of QInt type
211 * 'err_value' will be returned.
213 int64_t qdict_get_try_int(const QDict *qdict, const char *key,
214 int64_t err_value)
216 QObject *obj;
218 obj = qdict_get(qdict, key);
219 if (!obj || qobject_type(obj) != QTYPE_QINT)
220 return err_value;
222 return qint_get_int(qobject_to_qint(obj));
226 * qdict_get_try_str(): Try to get a pointer to the stored string
227 * mapped by 'key'
229 * Return a pointer to the string mapped by 'key', if it is not present
230 * in the dictionary or if the stored object is not of QString type
231 * NULL will be returned.
233 const char *qdict_get_try_str(const QDict *qdict, const char *key)
235 QObject *obj;
237 obj = qdict_get(qdict, key);
238 if (!obj || qobject_type(obj) != QTYPE_QSTRING)
239 return NULL;
241 return qstring_get_str(qobject_to_qstring(obj));
245 * qentry_destroy(): Free all the memory allocated by a QDictEntry
247 static void qentry_destroy(QDictEntry *e)
249 assert(e != NULL);
250 assert(e->key != NULL);
251 assert(e->value != NULL);
253 qobject_decref(e->value);
254 qemu_free(e->key);
255 qemu_free(e);
259 * qdict_del(): Delete a 'key:value' pair from the dictionary
261 * This will destroy all data allocated by this entry.
263 void qdict_del(QDict *qdict, const char *key)
265 QDictEntry *entry;
267 entry = qdict_find(qdict, key, tdb_hash(key) % QDICT_HASH_SIZE);
268 if (entry) {
269 LIST_REMOVE(entry, next);
270 qentry_destroy(entry);
271 qdict->size--;
276 * qdict_destroy_obj(): Free all the memory allocated by a QDict
278 static void qdict_destroy_obj(QObject *obj)
280 int i;
281 QDict *qdict;
283 assert(obj != NULL);
284 qdict = qobject_to_qdict(obj);
286 for (i = 0; i < QDICT_HASH_SIZE; i++) {
287 QDictEntry *entry = LIST_FIRST(&qdict->table[i]);
288 while (entry) {
289 QDictEntry *tmp = LIST_NEXT(entry, next);
290 LIST_REMOVE(entry, next);
291 qentry_destroy(entry);
292 entry = tmp;
296 qemu_free(qdict);