dict: add AV_DICT_APPEND flag.
[libav.git] / libavutil / dict.h
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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 Public dictionary API.
22 */
23
24#ifndef AVUTIL_DICT_H
25#define AVUTIL_DICT_H
26
27#define AV_DICT_MATCH_CASE 1
28#define AV_DICT_IGNORE_SUFFIX 2
29#define AV_DICT_DONT_STRDUP_KEY 4
30#define AV_DICT_DONT_STRDUP_VAL 8
31#define AV_DICT_DONT_OVERWRITE 16 ///< Don't overwrite existing entries.
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32#define AV_DICT_APPEND 32 /**< If the entry already exists, append to it. Note that no
33 delimiter is added, the strings are simply concatenated. */
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34
35typedef struct {
36 char *key;
37 char *value;
38} AVDictionaryEntry;
39
40typedef struct AVDictionary AVDictionary;
41
42/**
43 * Get a dictionary entry with matching key.
44 *
45 * @param prev Set to the previous matching element to find the next.
46 * If set to NULL the first matching element is returned.
47 * @param flags Allows case as well as suffix-insensitive comparisons.
48 * @return Found entry or NULL, changing key or value leads to undefined behavior.
49 */
50AVDictionaryEntry *
51av_dict_get(AVDictionary *m, const char *key, const AVDictionaryEntry *prev, int flags);
52
53/**
54 * Set the given entry in *pm, overwriting an existing entry.
55 *
56 * @param pm pointer to a pointer to a dictionary struct. If *pm is NULL
57 * a dictionary struct is allocated and put in *pm.
58 * @param key entry key to add to *pm (will be av_strduped depending on flags)
59 * @param value entry value to add to *pm (will be av_strduped depending on flags).
60 * Passing a NULL value will cause an existing tag to be deleted.
61 * @return >= 0 on success otherwise an error code <0
62 */
63int av_dict_set(AVDictionary **pm, const char *key, const char *value, int flags);
64
65/**
66 * Copy entries from one AVDictionary struct into another.
67 * @param dst pointer to a pointer to a AVDictionary struct. If *dst is NULL,
68 * this function will allocate a struct for you and put it in *dst
69 * @param src pointer to source AVDictionary struct
70 * @param flags flags to use when setting entries in *dst
71 * @note metadata is read using the AV_DICT_IGNORE_SUFFIX flag
72 */
73void av_dict_copy(AVDictionary **dst, AVDictionary *src, int flags);
74
75/**
76 * Free all the memory allocated for an AVDictionary struct.
77 */
78void av_dict_free(AVDictionary **m);
79
80#endif // AVUTIL_DICT_H