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 */ 153