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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. * @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. #ifndef AVUTIL_DICT_H
  30. #define AVUTIL_DICT_H
  31. /**
  32. * @addtogroup lavu_dict AVDictionary
  33. * @ingroup lavu_data
  34. *
  35. * @brief Simple key:value store
  36. *
  37. * @{
  38. * Dictionaries are used for storing key:value pairs. To create
  39. * an AVDictionary, simply pass an address of a NULL pointer to
  40. * av_dict_set(). NULL can be used as an empty dictionary wherever
  41. * a pointer to an AVDictionary is required.
  42. * Use av_dict_get() to retrieve an entry or iterate over all
  43. * entries and finally av_dict_free() to free the dictionary
  44. * and all its contents.
  45. *
  46. * @code
  47. * AVDictionary *d = NULL; // "create" an empty dictionary
  48. * av_dict_set(&d, "foo", "bar", 0); // add an entry
  49. *
  50. * char *k = av_strdup("key"); // if your strings are already allocated,
  51. * char *v = av_strdup("value"); // you can avoid copying them like this
  52. * av_dict_set(&d, k, v, AV_DICT_DONT_STRDUP_KEY | AV_DICT_DONT_STRDUP_VAL);
  53. *
  54. * AVDictionaryEntry *t = NULL;
  55. * while (t = av_dict_get(d, "", t, AV_DICT_IGNORE_SUFFIX)) {
  56. * <....> // iterate over all entries in d
  57. * }
  58. *
  59. * av_dict_free(&d);
  60. * @endcode
  61. *
  62. */
  63. #define AV_DICT_MATCH_CASE 1 /**< Only get an entry with exact-case key match. Only relevant in av_dict_get(). */
  64. #define AV_DICT_IGNORE_SUFFIX 2 /**< Return first entry in a dictionary whose first part corresponds to the search key,
  65. ignoring the suffix of the found key string. Only relevant in av_dict_get(). */
  66. #define AV_DICT_DONT_STRDUP_KEY 4 /**< Take ownership of a key that's been
  67. allocated with av_malloc() or another memory allocation function. */
  68. #define AV_DICT_DONT_STRDUP_VAL 8 /**< Take ownership of a value that's been
  69. allocated with av_malloc() or another memory allocation function. */
  70. #define AV_DICT_DONT_OVERWRITE 16 ///< Don't overwrite existing entries.
  71. #define AV_DICT_APPEND 32 /**< If the entry already exists, append to it. Note that no
  72. delimiter is added, the strings are simply concatenated. */
  73. typedef struct AVDictionaryEntry {
  74. char *key;
  75. char *value;
  76. } AVDictionaryEntry;
  77. typedef struct AVDictionary AVDictionary;
  78. /**
  79. * Get a dictionary entry with matching key.
  80. *
  81. * The returned entry key or value must not be changed, or it will
  82. * cause undefined behavior.
  83. *
  84. * To iterate through all the dictionary entries, you can set the matching key
  85. * to the null string "" and set the AV_DICT_IGNORE_SUFFIX flag.
  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 key matching key
  90. * @param flags a collection of AV_DICT_* flags controlling how the entry is retrieved
  91. * @return found entry or NULL in case no matching entry was found in the dictionary
  92. */
  93. AVDictionaryEntry *
  94. av_dict_get(AVDictionary *m, const char *key, const AVDictionaryEntry *prev, int flags);
  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. * Set the given entry in *pm, overwriting an existing entry.
  104. *
  105. * @param pm pointer to a pointer to a dictionary struct. If *pm is NULL
  106. * a dictionary struct is allocated and put in *pm.
  107. * @param key entry key to add to *pm (will be av_strduped depending on flags)
  108. * @param value entry value to add to *pm (will be av_strduped depending on flags).
  109. * Passing a NULL value will cause an existing entry to be deleted.
  110. * @return >= 0 on success otherwise an error code <0
  111. */
  112. int av_dict_set(AVDictionary **pm, const char *key, const char *value, int flags);
  113. /**
  114. * Parse the key/value pairs list and add the parsed entries to a dictionary.
  115. *
  116. * In case of failure, all the successfully set entries are stored in
  117. * *pm. You may need to manually free the created dictionary.
  118. *
  119. * @param key_val_sep a 0-terminated list of characters used to separate
  120. * key from value
  121. * @param pairs_sep a 0-terminated list of characters used to separate
  122. * two pairs from each other
  123. * @param flags flags to use when adding to dictionary.
  124. * AV_DICT_DONT_STRDUP_KEY and AV_DICT_DONT_STRDUP_VAL
  125. * are ignored since the key/value tokens will always
  126. * be duplicated.
  127. * @return 0 on success, negative AVERROR code on failure
  128. */
  129. int av_dict_parse_string(AVDictionary **pm, const char *str,
  130. const char *key_val_sep, const char *pairs_sep,
  131. int flags);
  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. * Free all the memory allocated for an AVDictionary struct
  143. * and all keys and values.
  144. */
  145. void av_dict_free(AVDictionary **m);
  146. /**
  147. * @}
  148. */
  149. #endif /* AVUTIL_DICT_H */