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  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.