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comparison lib/libavutil/dict.h @ 2134:992d2e6f907d

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preparation for libavcodec
author zipi
date Tue, 31 Dec 2013 14:52:14 +0000
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2133:e378232bfd36 2134:992d2e6f907d
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 /**
35 * @addtogroup lavu_dict AVDictionary
36 * @ingroup lavu_data
37 *
38 * @brief Simple key:value store
39 *
40 * @{
41 * Dictionaries are used for storing key:value pairs. To create
42 * an AVDictionary, simply pass an address of a NULL pointer to
43 * av_dict_set(). NULL can be used as an empty dictionary wherever
44 * a pointer to an AVDictionary is required.
45 * Use av_dict_get() to retrieve an entry or iterate over all
46 * entries and finally av_dict_free() to free the dictionary
47 * and all its contents.
48 *
49 * @code
50 * AVDictionary *d = NULL; // "create" an empty dictionary
51 * av_dict_set(&d, "foo", "bar", 0); // add an entry
52 *
53 * char *k = av_strdup("key"); // if your strings are already allocated,
54 * char *v = av_strdup("value"); // you can avoid copying them like this
55 * av_dict_set(&d, k, v, AV_DICT_DONT_STRDUP_KEY | AV_DICT_DONT_STRDUP_VAL);
56 *
57 * AVDictionaryEntry *t = NULL;
58 * while (t = av_dict_get(d, "", t, AV_DICT_IGNORE_SUFFIX)) {
59 * <....> // iterate over all entries in d
60 * }
61 *
62 * av_dict_free(&d);
63 * @endcode
64 *
65 */
66
67 #define AV_DICT_MATCH_CASE 1
68 #define AV_DICT_IGNORE_SUFFIX 2
69 #define AV_DICT_DONT_STRDUP_KEY 4 /**< Take ownership of a key that's been
70 allocated with av_malloc() and children. */
71 #define AV_DICT_DONT_STRDUP_VAL 8 /**< Take ownership of a value that's been
72 allocated with av_malloc() and chilren. */
73 #define AV_DICT_DONT_OVERWRITE 16 ///< Don't overwrite existing entries.
74 #define AV_DICT_APPEND 32 /**< If the entry already exists, append to it. Note that no
75 delimiter is added, the strings are simply concatenated. */
76
77 typedef struct AVDictionaryEntry {
78 char *key;
79 char *value;
80 } AVDictionaryEntry;
81
82 typedef struct AVDictionary AVDictionary;
83
84 /**
85 * Get a dictionary entry with matching key.
86 *
87 * @param prev Set to the previous matching element to find the next.
88 * If set to NULL the first matching element is returned.
89 * @param flags Allows case as well as suffix-insensitive comparisons.
90 * @return Found entry or NULL, changing key or value leads to undefined behavior.
91 */
92 AVDictionaryEntry *
93 av_dict_get(AVDictionary *m, const char *key, const AVDictionaryEntry *prev, int flags);
94
95 /**
96 * Get number of entries in dictionary.
97 *
98 * @param m dictionary
99 * @return number of entries in dictionary
100 */
101 int av_dict_count(const AVDictionary *m);
102
103 /**
104 * Set the given entry in *pm, overwriting an existing entry.
105 *
106 * @param pm pointer to a pointer to a dictionary struct. If *pm is NULL
107 * a dictionary struct is allocated and put in *pm.
108 * @param key entry key to add to *pm (will be av_strduped depending on flags)
109 * @param value entry value to add to *pm (will be av_strduped depending on flags).
110 * Passing a NULL value will cause an existing entry to be deleted.
111 * @return >= 0 on success otherwise an error code <0
112 */
113 int av_dict_set(AVDictionary **pm, const char *key, const char *value, int flags);
114
115 /**
116 * Parse the key/value pairs list and add to a dictionary.
117 *
118 * @param key_val_sep a 0-terminated list of characters used to separate
119 * key from value
120 * @param pairs_sep a 0-terminated list of characters used to separate
121 * two pairs from each other
122 * @param flags flags to use when adding to dictionary.
123 * AV_DICT_DONT_STRDUP_KEY and AV_DICT_DONT_STRDUP_VAL
124 * are ignored since the key/value tokens will always
125 * be duplicated.
126 * @return 0 on success, negative AVERROR code on failure
127 */
128 int av_dict_parse_string(AVDictionary **pm, const char *str,
129 const char *key_val_sep, const char *pairs_sep,
130 int flags);
131
132 /**
133 * Copy entries from one AVDictionary struct into another.
134 * @param dst pointer to a pointer to a AVDictionary struct. If *dst is NULL,
135 * this function will allocate a struct for you and put it in *dst
136 * @param src pointer to source AVDictionary struct
137 * @param flags flags to use when setting entries in *dst
138 * @note metadata is read using the AV_DICT_IGNORE_SUFFIX flag
139 */
140 void av_dict_copy(AVDictionary **dst, AVDictionary *src, int flags);
141
142 /**
143 * Free all the memory allocated for an AVDictionary struct
144 * and all keys and values.
145 */
146 void av_dict_free(AVDictionary **m);
147
148 /**
149 * @}
150 */
151
152 #endif /* AVUTIL_DICT_H */