1/*
2 *
3 * This file is part of Libav.
4 *
5 * Libav is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2.1 of the License, or (at your option) any later version.
9 *
10 * Libav is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13 * Lesser General Public License for more details.
14 *
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with Libav; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
18 */
19
20/**
21 * @file
22 * Public dictionary API.
23 */
24
25#ifndef AVUTIL_DICT_H
26#define AVUTIL_DICT_H
27
28/**
29 * @addtogroup lavu_dict AVDictionary
30 * @ingroup lavu_data
31 *
32 * @brief Simple key:value store
33 *
34 * @{
35 * Dictionaries are used for storing key:value pairs. To create
36 * an AVDictionary, simply pass an address of a NULL pointer to
37 * av_dict_set(). NULL can be used as an empty dictionary wherever
38 * a pointer to an AVDictionary is required.
39 * Use av_dict_get() to retrieve an entry or iterate over all
40 * entries and finally av_dict_free() to free the dictionary
41 * and all its contents.
42 *
43 * @code
44 * AVDictionary *d = NULL;                // "create" an empty dictionary
45 * av_dict_set(&d, "foo", "bar", 0);      // add an entry
46 *
47 * char *k = av_strdup("key");            // if your strings are already allocated,
48 * char *v = av_strdup("value");          // you can avoid copying them like this
49 * av_dict_set(&d, k, v, AV_DICT_DONT_STRDUP_KEY | AV_DICT_DONT_STRDUP_VAL);
50 *
51 * AVDictionaryEntry *t = NULL;
52 * while (t = av_dict_get(d, "", t, AV_DICT_IGNORE_SUFFIX)) {
53 *     <....>                             // iterate over all entries in d
54 * }
55 *
56 * av_dict_free(&d);
57 * @endcode
58 *
59 */
60
61#define AV_DICT_MATCH_CASE      1
62#define AV_DICT_IGNORE_SUFFIX   2
63#define AV_DICT_DONT_STRDUP_KEY 4   /**< Take ownership of a key that's been
64                                         allocated with av_malloc() and children. */
65#define AV_DICT_DONT_STRDUP_VAL 8   /**< Take ownership of a value that's been
66                                         allocated with av_malloc() and chilren. */
67#define AV_DICT_DONT_OVERWRITE 16   ///< Don't overwrite existing entries.
68#define AV_DICT_APPEND         32   /**< If the entry already exists, append to it.  Note that no
69                                      delimiter is added, the strings are simply concatenated. */
70
71typedef struct {
72    char *key;
73    char *value;
74} AVDictionaryEntry;
75
76typedef struct AVDictionary AVDictionary;
77
78/**
79 * Get a dictionary entry with matching key.
80 *
81 * @param prev Set to the previous matching element to find the next.
82 *             If set to NULL the first matching element is returned.
83 * @param flags Allows case as well as suffix-insensitive comparisons.
84 * @return Found entry or NULL, changing key or value leads to undefined behavior.
85 */
86AVDictionaryEntry *
87av_dict_get(AVDictionary *m, const char *key, const AVDictionaryEntry *prev, int flags);
88
89/**
90 * Set the given entry in *pm, overwriting an existing entry.
91 *
92 * @param pm pointer to a pointer to a dictionary struct. If *pm is NULL
93 * a dictionary struct is allocated and put in *pm.
94 * @param key entry key to add to *pm (will be av_strduped depending on flags)
95 * @param value entry value to add to *pm (will be av_strduped depending on flags).
96 *        Passing a NULL value will cause an existing tag to be deleted.
97 * @return >= 0 on success otherwise an error code <0
98 */
99int av_dict_set(AVDictionary **pm, const char *key, const char *value, int flags);
100
101/**
102 * Copy entries from one AVDictionary struct into another.
103 * @param dst pointer to a pointer to a AVDictionary struct. If *dst is NULL,
104 *            this function will allocate a struct for you and put it in *dst
105 * @param src pointer to source AVDictionary struct
106 * @param flags flags to use when setting entries in *dst
107 * @note metadata is read using the AV_DICT_IGNORE_SUFFIX flag
108 */
109void av_dict_copy(AVDictionary **dst, AVDictionary *src, int flags);
110
111/**
112 * Free all the memory allocated for an AVDictionary struct
113 * and all keys and values.
114 */
115void av_dict_free(AVDictionary **m);
116
117/**
118 * @}
119 */
120
121#endif // AVUTIL_DICT_H
122