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