blob: 118f1f00ed2046fa5ae5a2440a5961190d923e3a
| 1 | /* |
| 2 | * This file is part of FFmpeg. |
| 3 | * |
| 4 | * FFmpeg is free software; you can redistribute it and/or |
| 5 | * modify it under the terms of the GNU Lesser General Public |
| 6 | * License as published by the Free Software Foundation; either |
| 7 | * version 2.1 of the License, or (at your option) any later version. |
| 8 | * |
| 9 | * FFmpeg is distributed in the hope that it will be useful, |
| 10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 12 | * Lesser General Public License for more details. |
| 13 | * |
| 14 | * You should have received a copy of the GNU Lesser General Public |
| 15 | * License along with FFmpeg; if not, write to the Free Software |
| 16 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 17 | */ |
| 18 | |
| 19 | /** |
| 20 | * @file |
| 21 | * Public dictionary API. |
| 22 | * @deprecated |
| 23 | * AVDictionary is provided for compatibility with libav. It is both in |
| 24 | * implementation as well as API inefficient. It does not scale and is |
| 25 | * extremely slow with large dictionaries. |
| 26 | * It is recommended that new code uses our tree container from tree.c/h |
| 27 | * where applicable, which uses AVL trees to achieve O(log n) performance. |
| 28 | */ |
| 29 | |
| 30 | #ifndef AVUTIL_DICT_H |
| 31 | #define AVUTIL_DICT_H |
| 32 | |
| 33 | #include <stdint.h> |
| 34 | |
| 35 | #include "version.h" |
| 36 | |
| 37 | /** |
| 38 | * @addtogroup lavu_dict AVDictionary |
| 39 | * @ingroup lavu_data |
| 40 | * |
| 41 | * @brief Simple key:value store |
| 42 | * |
| 43 | * @{ |
| 44 | * Dictionaries are used for storing key:value pairs. To create |
| 45 | * an AVDictionary, simply pass an address of a NULL pointer to |
| 46 | * av_dict_set(). NULL can be used as an empty dictionary wherever |
| 47 | * a pointer to an AVDictionary is required. |
| 48 | * Use av_dict_get() to retrieve an entry or iterate over all |
| 49 | * entries and finally av_dict_free() to free the dictionary |
| 50 | * and all its contents. |
| 51 | * |
| 52 | @code |
| 53 | AVDictionary *d = NULL; // "create" an empty dictionary |
| 54 | AVDictionaryEntry *t = NULL; |
| 55 | |
| 56 | av_dict_set(&d, "foo", "bar", 0); // add an entry |
| 57 | |
| 58 | char *k = av_strdup("key"); // if your strings are already allocated, |
| 59 | char *v = av_strdup("value"); // you can avoid copying them like this |
| 60 | av_dict_set(&d, k, v, AV_DICT_DONT_STRDUP_KEY | AV_DICT_DONT_STRDUP_VAL); |
| 61 | |
| 62 | while (t = av_dict_get(d, "", t, AV_DICT_IGNORE_SUFFIX)) { |
| 63 | <....> // iterate over all entries in d |
| 64 | } |
| 65 | av_dict_free(&d); |
| 66 | @endcode |
| 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 | #define AV_DICT_MULTIKEY 64 /**< Allow to store several equal keys in the dictionary */ |
| 80 | |
| 81 | typedef struct AVDictionaryEntry { |
| 82 | char *key; |
| 83 | char *value; |
| 84 | } AVDictionaryEntry; |
| 85 | |
| 86 | typedef struct AVDictionary AVDictionary; |
| 87 | |
| 88 | /** |
| 89 | * Get a dictionary entry with matching key. |
| 90 | * |
| 91 | * The returned entry key or value must not be changed, or it will |
| 92 | * cause undefined behavior. |
| 93 | * |
| 94 | * To iterate through all the dictionary entries, you can set the matching key |
| 95 | * to the null string "" and set the AV_DICT_IGNORE_SUFFIX flag. |
| 96 | * |
| 97 | * @param prev Set to the previous matching element to find the next. |
| 98 | * If set to NULL the first matching element is returned. |
| 99 | * @param key matching key |
| 100 | * @param flags a collection of AV_DICT_* flags controlling how the entry is retrieved |
| 101 | * @return found entry or NULL in case no matching entry was found in the dictionary |
| 102 | */ |
| 103 | AVDictionaryEntry *av_dict_get(const AVDictionary *m, const char *key, |
| 104 | const AVDictionaryEntry *prev, int flags); |
| 105 | |
| 106 | /** |
| 107 | * Get number of entries in dictionary. |
| 108 | * |
| 109 | * @param m dictionary |
| 110 | * @return number of entries in dictionary |
| 111 | */ |
| 112 | int av_dict_count(const AVDictionary *m); |
| 113 | |
| 114 | /** |
| 115 | * Set the given entry in *pm, overwriting an existing entry. |
| 116 | * |
| 117 | * Note: If AV_DICT_DONT_STRDUP_KEY or AV_DICT_DONT_STRDUP_VAL is set, |
| 118 | * these arguments will be freed on error. |
| 119 | * |
| 120 | * Warning: Adding a new entry to a dictionary invalidates all existing entries |
| 121 | * previously returned with av_dict_get. |
| 122 | * |
| 123 | * @param pm pointer to a pointer to a dictionary struct. If *pm is NULL |
| 124 | * a dictionary struct is allocated and put in *pm. |
| 125 | * @param key entry key to add to *pm (will either be av_strduped or added as a new key depending on flags) |
| 126 | * @param value entry value to add to *pm (will be av_strduped or added as a new key depending on flags). |
| 127 | * Passing a NULL value will cause an existing entry to be deleted. |
| 128 | * @return >= 0 on success otherwise an error code <0 |
| 129 | */ |
| 130 | int av_dict_set(AVDictionary **pm, const char *key, const char *value, int flags); |
| 131 | |
| 132 | /** |
| 133 | * Convenience wrapper for av_dict_set that converts the value to a string |
| 134 | * and stores it. |
| 135 | * |
| 136 | * Note: If AV_DICT_DONT_STRDUP_KEY is set, key will be freed on error. |
| 137 | */ |
| 138 | int av_dict_set_int(AVDictionary **pm, const char *key, int64_t value, int flags); |
| 139 | |
| 140 | /** |
| 141 | * Parse the key/value pairs list and add the parsed entries to a dictionary. |
| 142 | * |
| 143 | * In case of failure, all the successfully set entries are stored in |
| 144 | * *pm. You may need to manually free the created dictionary. |
| 145 | * |
| 146 | * @param key_val_sep a 0-terminated list of characters used to separate |
| 147 | * key from value |
| 148 | * @param pairs_sep a 0-terminated list of characters used to separate |
| 149 | * two pairs from each other |
| 150 | * @param flags flags to use when adding to dictionary. |
| 151 | * AV_DICT_DONT_STRDUP_KEY and AV_DICT_DONT_STRDUP_VAL |
| 152 | * are ignored since the key/value tokens will always |
| 153 | * be duplicated. |
| 154 | * @return 0 on success, negative AVERROR code on failure |
| 155 | */ |
| 156 | int av_dict_parse_string(AVDictionary **pm, const char *str, |
| 157 | const char *key_val_sep, const char *pairs_sep, |
| 158 | int flags); |
| 159 | |
| 160 | /** |
| 161 | * Copy entries from one AVDictionary struct into another. |
| 162 | * @param dst pointer to a pointer to a AVDictionary struct. If *dst is NULL, |
| 163 | * this function will allocate a struct for you and put it in *dst |
| 164 | * @param src pointer to source AVDictionary struct |
| 165 | * @param flags flags to use when setting entries in *dst |
| 166 | * @note metadata is read using the AV_DICT_IGNORE_SUFFIX flag |
| 167 | * @return 0 on success, negative AVERROR code on failure. If dst was allocated |
| 168 | * by this function, callers should free the associated memory. |
| 169 | */ |
| 170 | int av_dict_copy(AVDictionary **dst, const AVDictionary *src, int flags); |
| 171 | |
| 172 | /** |
| 173 | * Free all the memory allocated for an AVDictionary struct |
| 174 | * and all keys and values. |
| 175 | */ |
| 176 | void av_dict_free(AVDictionary **m); |
| 177 | |
| 178 | /** |
| 179 | * Get dictionary entries as a string. |
| 180 | * |
| 181 | * Create a string containing dictionary's entries. |
| 182 | * Such string may be passed back to av_dict_parse_string(). |
| 183 | * @note String is escaped with backslashes ('\'). |
| 184 | * |
| 185 | * @param[in] m dictionary |
| 186 | * @param[out] buffer Pointer to buffer that will be allocated with string containg entries. |
| 187 | * Buffer must be freed by the caller when is no longer needed. |
| 188 | * @param[in] key_val_sep character used to separate key from value |
| 189 | * @param[in] pairs_sep character used to separate two pairs from each other |
| 190 | * @return >= 0 on success, negative on error |
| 191 | * @warning Separators cannot be neither '\\' nor '\0'. They also cannot be the same. |
| 192 | */ |
| 193 | int av_dict_get_string(const AVDictionary *m, char **buffer, |
| 194 | const char key_val_sep, const char pairs_sep); |
| 195 | |
| 196 | /** |
| 197 | * @} |
| 198 | */ |
| 199 | |
| 200 | #endif /* AVUTIL_DICT_H */ |
| 201 |