/* * This file is part of FFmpeg. * * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * FFmpeg is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** * @file * Public dictionary API. * @deprecated * AVDictionary is provided for compatibility with libav. It is both in * implementation as well as API inefficient. It does not scale and is * extremely slow with large dictionaries. * It is recommended that new code uses our tree container from tree.c/h * where applicable, which uses AVL trees to achieve O(log n) performance. */ #ifndef AVUTIL_DICT_H #define AVUTIL_DICT_H #include <stdint.h> /** * @addtogroup lavu_dict AVDictionary * @ingroup lavu_data * * @brief Simple key:value store * * @{ * Dictionaries are used for storing key-value pairs. * * - To **create an AVDictionary**, simply pass an address of a NULL * pointer to av_dict_set(). NULL can be used as an empty dictionary * wherever a pointer to an AVDictionary is required. * - To **insert an entry**, use av_dict_set(). * - Use av_dict_get() to **retrieve an entry**. * - To **iterate over all entries**, use av_dict_iterate(). * - In order to **free the dictionary and all its contents**, use av_dict_free(). * @code AVDictionary *d = NULL; // "create" an empty dictionary AVDictionaryEntry *t = NULL; av_dict_set(&d, "foo", "bar", 0); // add an entry char *k = av_strdup("key"); // if your strings are already allocated, char *v = av_strdup("value"); // you can avoid copying them like this av_dict_set(&d, k, v, AV_DICT_DONT_STRDUP_KEY | AV_DICT_DONT_STRDUP_VAL); while ((t = av_dict_iterate(d, t))) { <....> // iterate over all entries in d } av_dict_free(&d); @endcode */ /** * @name AVDictionary Flags * Flags that influence behavior of the matching of keys or insertion to the dictionary. * @{ */ #define AV_DICT_MATCH_CASE 1 /**< Only get an entry with exact-case key match. Only relevant in av_dict_get(). */ #define AV_DICT_IGNORE_SUFFIX 2 /**< Return first entry in a dictionary whose first part corresponds to the search key, ignoring the suffix of the found key string. Only relevant in av_dict_get(). */ #define AV_DICT_DONT_STRDUP_KEY 4 /**< Take ownership of a key that's been allocated with av_malloc() or another memory allocation function. */ #define AV_DICT_DONT_STRDUP_VAL 8 /**< Take ownership of a value that's been allocated with av_malloc() or another memory allocation function. */ #define AV_DICT_DONT_OVERWRITE 16 /**< Don't overwrite existing entries. */ #define AV_DICT_APPEND 32 /**< If the entry already exists, append to it. Note that no delimiter is added, the strings are simply concatenated. */ #define AV_DICT_MULTIKEY 64 /**< Allow to store several equal keys in the dictionary */ /** * @} */ typedef struct AVDictionaryEntry { char *key; char *value; } AVDictionaryEntry; typedef struct AVDictionary AVDictionary; /** * Get a dictionary entry with matching key. * * The returned entry key or value must not be changed, or it will * cause undefined behavior. * * @param prev Set to the previous matching element to find the next. * If set to NULL the first matching element is returned. * @param key Matching key * @param flags A collection of AV_DICT_* flags controlling how the * entry is retrieved * * @return Found entry or NULL in case no matching entry was found in the dictionary */ AVDictionaryEntry *av_dict_get(const AVDictionary *m, const char *key, const AVDictionaryEntry *prev, int flags); /** * Iterate over a dictionary * * Iterates through all entries in the dictionary. * * @warning The returned AVDictionaryEntry key/value must not be changed. * * @warning As av_dict_set() invalidates all previous entries returned * by this function, it must not be called while iterating over the dict. * * Typical usage: * @code * const AVDictionaryEntry *e = NULL; * while ((e = av_dict_iterate(m, e))) { * // ... * } * @endcode * * @param m The dictionary to iterate over * @param prev Pointer to the previous AVDictionaryEntry, NULL initially * * @retval AVDictionaryEntry* The next element in the dictionary * @retval NULL No more elements in the dictionary */ const AVDictionaryEntry *av_dict_iterate(const AVDictionary *m, const AVDictionaryEntry *prev); /** * Get number of entries in dictionary. * * @param m dictionary * @return number of entries in dictionary */ int av_dict_count(const AVDictionary *m); /** * Set the given entry in *pm, overwriting an existing entry. * * Note: If AV_DICT_DONT_STRDUP_KEY or AV_DICT_DONT_STRDUP_VAL is set, * these arguments will be freed on error. * * @warning Adding a new entry to a dictionary invalidates all existing entries * previously returned with av_dict_get() or av_dict_iterate(). * * @param pm Pointer to a pointer to a dictionary struct. If *pm is NULL * a dictionary struct is allocated and put in *pm. * @param key Entry key to add to *pm (will either be av_strduped or added as a new key depending on flags) * @param value Entry value to add to *pm (will be av_strduped or added as a new key depending on flags). * Passing a NULL value will cause an existing entry to be deleted. * * @return >= 0 on success otherwise an error code <0 */ int av_dict_set(AVDictionary **pm, const char *key, const char *value, int flags); /** * Convenience wrapper for av_dict_set() that converts the value to a string * and stores it. * * Note: If ::AV_DICT_DONT_STRDUP_KEY is set, key will be freed on error. */ int av_dict_set_int(AVDictionary **pm, const char *key, int64_t value, int flags); /** * Parse the key/value pairs list and add the parsed entries to a dictionary. * * In case of failure, all the successfully set entries are stored in * *pm. You may need to manually free the created dictionary. * * @param key_val_sep A 0-terminated list of characters used to separate * key from value * @param pairs_sep A 0-terminated list of characters used to separate * two pairs from each other * @param flags Flags to use when adding to the dictionary. * ::AV_DICT_DONT_STRDUP_KEY and ::AV_DICT_DONT_STRDUP_VAL * are ignored since the key/value tokens will always * be duplicated. * * @return 0 on success, negative AVERROR code on failure */ int av_dict_parse_string(AVDictionary **pm, const char *str, const char *key_val_sep, const char *pairs_sep, int flags); /** * Copy entries from one AVDictionary struct into another. * * @note Metadata is read using the ::AV_DICT_IGNORE_SUFFIX flag * * @param dst Pointer to a pointer to a AVDictionary struct to copy into. If *dst is NULL, * this function will allocate a struct for you and put it in *dst * @param src Pointer to the source AVDictionary struct to copy items from. * @param flags Flags to use when setting entries in *dst * * @return 0 on success, negative AVERROR code on failure. If dst was allocated * by this function, callers should free the associated memory. */ int av_dict_copy(AVDictionary **dst, const AVDictionary *src, int flags); /** * Free all the memory allocated for an AVDictionary struct * and all keys and values. */ void av_dict_free(AVDictionary **m); /** * Get dictionary entries as a string. * * Create a string containing dictionary's entries. * Such string may be passed back to av_dict_parse_string(). * @note String is escaped with backslashes ('\'). * * @warning Separators cannot be neither '\\' nor '\0'. They also cannot be the same. * * @param[in] m The dictionary * @param[out] buffer Pointer to buffer that will be allocated with string containg entries. * Buffer must be freed by the caller when is no longer needed. * @param[in] key_val_sep Character used to separate key from value * @param[in] pairs_sep Character used to separate two pairs from each other * * @return >= 0 on success, negative on error */ int av_dict_get_string(const AVDictionary *m, char **buffer, const char key_val_sep, const char pairs_sep); /** * @} */ #endif /* AVUTIL_DICT_H */