1/*
2 * This file is part of FFmpeg.
3 *
4 * FFmpeg is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2.1 of the License, or (at your option) any later version.
8 *
9 * FFmpeg is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
13 *
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with FFmpeg; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17 */
18
19/**
20 * @file
21 * Public dictionary API.
22 * @deprecated
23 * AVDictionary is provided for compatibility with libav. It is both in
24 * implementation as well as API inefficient. It does not scale and is
25 * extremely slow with large dictionaries.
26 * It is recommended that new code uses our tree container from tree.c/h
27 * where applicable, which uses AVL trees to achieve O(log n) performance.
28 */
29
30#ifndef AVUTIL_DICT_H
31#define AVUTIL_DICT_H
32
33#include <stdint.h>
34
35#include "version.h"
36
37/**
38 * @addtogroup lavu_dict AVDictionary
39 * @ingroup lavu_data
40 *
41 * @brief Simple key:value store
42 *
43 * @{
44 * Dictionaries are used for storing key:value pairs. To create
45 * an AVDictionary, simply pass an address of a NULL pointer to
46 * av_dict_set(). NULL can be used as an empty dictionary wherever
47 * a pointer to an AVDictionary is required.
48 * Use av_dict_get() to retrieve an entry or iterate over all
49 * entries and finally av_dict_free() to free the dictionary
50 * and all its contents.
51 *
52 @code
53 AVDictionary *d = NULL; // "create" an empty dictionary
54 AVDictionaryEntry *t = NULL;
55
56 av_dict_set(&d, "foo", "bar", 0); // add an entry
57
58 char *k = av_strdup("key"); // if your strings are already allocated,
59 char *v = av_strdup("value"); // you can avoid copying them like this
60 av_dict_set(&d, k, v, AV_DICT_DONT_STRDUP_KEY | AV_DICT_DONT_STRDUP_VAL);
61
62 while (t = av_dict_get(d, "", t, AV_DICT_IGNORE_SUFFIX)) {
63 <....> // iterate over all entries in d
64 }
65 av_dict_free(&d);
66 @endcode
67 */
68
69#define AV_DICT_MATCH_CASE 1 /**< Only get an entry with exact-case key match. Only relevant in av_dict_get(). */
70#define AV_DICT_IGNORE_SUFFIX 2 /**< Return first entry in a dictionary whose first part corresponds to the search key,
71 ignoring the suffix of the found key string. Only relevant in av_dict_get(). */
72#define AV_DICT_DONT_STRDUP_KEY 4 /**< Take ownership of a key that's been
73 allocated with av_malloc() or another memory allocation function. */
74#define AV_DICT_DONT_STRDUP_VAL 8 /**< Take ownership of a value that's been
75 allocated with av_malloc() or another memory allocation function. */
76#define AV_DICT_DONT_OVERWRITE 16 ///< Don't overwrite existing entries.
77#define AV_DICT_APPEND 32 /**< If the entry already exists, append to it. Note that no
78 delimiter is added, the strings are simply concatenated. */
79#define AV_DICT_MULTIKEY 64 /**< Allow to store several equal keys in the dictionary */
80
81typedef struct AVDictionaryEntry {
82 char *key;
83 char *value;
84} AVDictionaryEntry;
85
86typedef struct AVDictionary AVDictionary;
87
88/**
89 * Get a dictionary entry with matching key.
90 *
91 * The returned entry key or value must not be changed, or it will
92 * cause undefined behavior.
93 *
94 * To iterate through all the dictionary entries, you can set the matching key
95 * to the null string "" and set the AV_DICT_IGNORE_SUFFIX flag.
96 *
97 * @param prev Set to the previous matching element to find the next.
98 * If set to NULL the first matching element is returned.
99 * @param key matching key
100 * @param flags a collection of AV_DICT_* flags controlling how the entry is retrieved
101 * @return found entry or NULL in case no matching entry was found in the dictionary
102 */
103AVDictionaryEntry *av_dict_get(const AVDictionary *m, const char *key,
104 const AVDictionaryEntry *prev, int flags);
105
106/**
107 * Get number of entries in dictionary.
108 *
109 * @param m dictionary
110 * @return number of entries in dictionary
111 */
112int av_dict_count(const AVDictionary *m);
113
114/**
115 * Set the given entry in *pm, overwriting an existing entry.
116 *
117 * Note: If AV_DICT_DONT_STRDUP_KEY or AV_DICT_DONT_STRDUP_VAL is set,
118 * these arguments will be freed on error.
119 *
120 * Warning: Adding a new entry to a dictionary invalidates all existing entries
121 * previously returned with av_dict_get.
122 *
123 * @param pm pointer to a pointer to a dictionary struct. If *pm is NULL
124 * a dictionary struct is allocated and put in *pm.
125 * @param key entry key to add to *pm (will either be av_strduped or added as a new key depending on flags)
126 * @param value entry value to add to *pm (will be av_strduped or added as a new key depending on flags).
127 * Passing a NULL value will cause an existing entry to be deleted.
128 * @return >= 0 on success otherwise an error code <0
129 */
130int av_dict_set(AVDictionary **pm, const char *key, const char *value, int flags);
131
132/**
133 * Convenience wrapper for av_dict_set that converts the value to a string
134 * and stores it.
135 *
136 * Note: If AV_DICT_DONT_STRDUP_KEY is set, key will be freed on error.
137 */
138int av_dict_set_int(AVDictionary **pm, const char *key, int64_t value, int flags);
139
140/**
141 * Parse the key/value pairs list and add the parsed entries to a dictionary.
142 *
143 * In case of failure, all the successfully set entries are stored in
144 * *pm. You may need to manually free the created dictionary.
145 *
146 * @param key_val_sep a 0-terminated list of characters used to separate
147 * key from value
148 * @param pairs_sep a 0-terminated list of characters used to separate
149 * two pairs from each other
150 * @param flags flags to use when adding to dictionary.
151 * AV_DICT_DONT_STRDUP_KEY and AV_DICT_DONT_STRDUP_VAL
152 * are ignored since the key/value tokens will always
153 * be duplicated.
154 * @return 0 on success, negative AVERROR code on failure
155 */
156int av_dict_parse_string(AVDictionary **pm, const char *str,
157 const char *key_val_sep, const char *pairs_sep,
158 int flags);
159
160/**
161 * Copy entries from one AVDictionary struct into another.
162 * @param dst pointer to a pointer to a AVDictionary struct. If *dst is NULL,
163 * this function will allocate a struct for you and put it in *dst
164 * @param src pointer to source AVDictionary struct
165 * @param flags flags to use when setting entries in *dst
166 * @note metadata is read using the AV_DICT_IGNORE_SUFFIX flag
167 * @return 0 on success, negative AVERROR code on failure. If dst was allocated
168 * by this function, callers should free the associated memory.
169 */
170int av_dict_copy(AVDictionary **dst, const AVDictionary *src, int flags);
171
172/**
173 * Free all the memory allocated for an AVDictionary struct
174 * and all keys and values.
175 */
176void av_dict_free(AVDictionary **m);
177
178/**
179 * Get dictionary entries as a string.
180 *
181 * Create a string containing dictionary's entries.
182 * Such string may be passed back to av_dict_parse_string().
183 * @note String is escaped with backslashes ('\').
184 *
185 * @param[in] m dictionary
186 * @param[out] buffer Pointer to buffer that will be allocated with string containg entries.
187 * Buffer must be freed by the caller when is no longer needed.
188 * @param[in] key_val_sep character used to separate key from value
189 * @param[in] pairs_sep character used to separate two pairs from each other
190 * @return >= 0 on success, negative on error
191 * @warning Separators cannot be neither '\\' nor '\0'. They also cannot be the same.
192 */
193int av_dict_get_string(const AVDictionary *m, char **buffer,
194 const char key_val_sep, const char pairs_sep);
195
196/**
197 * @}
198 */
199
200#endif /* AVUTIL_DICT_H */
201

source code of include/x86_64-linux-gnu/libavutil/dict.h