1/*
2 *
3 * This file is part of FFmpeg.
4 *
5 * FFmpeg 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 * FFmpeg 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 FFmpeg; 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 * @deprecated
24 *  AVDictionary is provided for compatibility with libav. It is both in
25 *  implementation as well as API inefficient. It does not scale and is
26 *  extremely slow with large dictionaries.
27 *  It is recommended that new code uses our tree container from tree.c/h
28 *  where applicable, which uses AVL trees to achieve O(log n) performance.
29 */
30
31#ifndef AVUTIL_DICT_H
32#define AVUTIL_DICT_H
33
34#include "version.h"
35
36/**
37 * @addtogroup lavu_dict AVDictionary
38 * @ingroup lavu_data
39 *
40 * @brief Simple key:value store
41 *
42 * @{
43 * Dictionaries are used for storing key:value pairs. To create
44 * an AVDictionary, simply pass an address of a NULL pointer to
45 * av_dict_set(). NULL can be used as an empty dictionary wherever
46 * a pointer to an AVDictionary is required.
47 * Use av_dict_get() to retrieve an entry or iterate over all
48 * entries and finally av_dict_free() to free the dictionary
49 * and all its contents.
50 *
51 @code
52   AVDictionary *d = NULL;           // "create" an empty dictionary
53   AVDictionaryEntry *t = NULL;
54
55   av_dict_set(&d, "foo", "bar", 0); // add an entry
56
57   char *k = av_strdup("key");       // if your strings are already allocated,
58   char *v = av_strdup("value");     // you can avoid copying them like this
59   av_dict_set(&d, k, v, AV_DICT_DONT_STRDUP_KEY | AV_DICT_DONT_STRDUP_VAL);
60
61   while (t = av_dict_get(d, "", t, AV_DICT_IGNORE_SUFFIX)) {
62       <....>                             // iterate over all entries in d
63   }
64   av_dict_free(&d);
65 @endcode
66 *
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
80typedef struct AVDictionaryEntry {
81    char *key;
82    char *value;
83} AVDictionaryEntry;
84
85typedef struct AVDictionary AVDictionary;
86
87/**
88 * Get a dictionary entry with matching key.
89 *
90 * The returned entry key or value must not be changed, or it will
91 * cause undefined behavior.
92 *
93 * To iterate through all the dictionary entries, you can set the matching key
94 * to the null string "" and set the AV_DICT_IGNORE_SUFFIX flag.
95 *
96 * @param prev Set to the previous matching element to find the next.
97 *             If set to NULL the first matching element is returned.
98 * @param key matching key
99 * @param flags a collection of AV_DICT_* flags controlling how the entry is retrieved
100 * @return found entry or NULL in case no matching entry was found in the dictionary
101 */
102AVDictionaryEntry *av_dict_get(FF_CONST_AVUTIL53 AVDictionary *m, const char *key,
103                               const AVDictionaryEntry *prev, int flags);
104
105/**
106 * Get number of entries in dictionary.
107 *
108 * @param m dictionary
109 * @return  number of entries in dictionary
110 */
111int av_dict_count(const AVDictionary *m);
112
113/**
114 * Set the given entry in *pm, overwriting an existing entry.
115 *
116 * @param pm pointer to a pointer to a dictionary struct. If *pm is NULL
117 * a dictionary struct is allocated and put in *pm.
118 * @param key entry key to add to *pm (will be av_strduped depending on flags)
119 * @param value entry value to add to *pm (will be av_strduped depending on flags).
120 *        Passing a NULL value will cause an existing entry to be deleted.
121 * @return >= 0 on success otherwise an error code <0
122 */
123int av_dict_set(AVDictionary **pm, const char *key, const char *value, int flags);
124
125/**
126 * Parse the key/value pairs list and add the parsed entries to a dictionary.
127 *
128 * In case of failure, all the successfully set entries are stored in
129 * *pm. You may need to manually free the created dictionary.
130 *
131 * @param key_val_sep  a 0-terminated list of characters used to separate
132 *                     key from value
133 * @param pairs_sep    a 0-terminated list of characters used to separate
134 *                     two pairs from each other
135 * @param flags        flags to use when adding to dictionary.
136 *                     AV_DICT_DONT_STRDUP_KEY and AV_DICT_DONT_STRDUP_VAL
137 *                     are ignored since the key/value tokens will always
138 *                     be duplicated.
139 * @return             0 on success, negative AVERROR code on failure
140 */
141int av_dict_parse_string(AVDictionary **pm, const char *str,
142                         const char *key_val_sep, const char *pairs_sep,
143                         int flags);
144
145/**
146 * Copy entries from one AVDictionary struct into another.
147 * @param dst pointer to a pointer to a AVDictionary struct. If *dst is NULL,
148 *            this function will allocate a struct for you and put it in *dst
149 * @param src pointer to source AVDictionary struct
150 * @param flags flags to use when setting entries in *dst
151 * @note metadata is read using the AV_DICT_IGNORE_SUFFIX flag
152 */
153void av_dict_copy(AVDictionary **dst, FF_CONST_AVUTIL53 AVDictionary *src, int flags);
154
155/**
156 * Free all the memory allocated for an AVDictionary struct
157 * and all keys and values.
158 */
159void av_dict_free(AVDictionary **m);
160
161/**
162 * @}
163 */
164
165#endif /* AVUTIL_DICT_H */
166