libavutil/dict.h - third_party/ffmpeg - Git at Google

 /*
  * 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>

 #include "version.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.
  * Use av_dict_get() to retrieve an entry or iterate over all
  * entries and finally av_dict_free() to free the dictionary
  * and all its contents.
  *
  @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_get(d, "", t, AV_DICT_IGNORE_SUFFIX)) {
        <....>                             // iterate over all entries in d
    }
    av_dict_free(&d);
  @endcode
  */

 #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.
  *
  * To iterate through all the dictionary entries, you can set the matching key
  * to the null string "" and set the AV_DICT_IGNORE_SUFFIX flag.
  *
  * @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);

 /**
  * 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.
  *
  * @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 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.
  * @param dst pointer to a pointer to a AVDictionary struct. If *dst is NULL,
  *            this function will allocate a struct for you and put it in *dst
  * @param src pointer to source AVDictionary struct
  * @param flags flags to use when setting entries in *dst
  * @note metadata is read using the AV_DICT_IGNORE_SUFFIX flag
  * @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 ('\').
  *
  * @param[in]  m             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
  * @warning Separators cannot be neither '\\' nor '\0'. They also cannot be the same.
  */
 int av_dict_get_string(const AVDictionary *m, char **buffer,
                        const char key_val_sep, const char pairs_sep);

 /**
  * @}
  */

 #endif /* AVUTIL_DICT_H */
	/*
	* 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>

	#include "version.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.
	* Use av_dict_get() to retrieve an entry or iterate over all
	* entries and finally av_dict_free() to free the dictionary
	* and all its contents.
	*
	@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_get(d, "", t, AV_DICT_IGNORE_SUFFIX)) {
	<....> // iterate over all entries in d
	}
	av_dict_free(&d);
	@endcode
	*/

	#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.
	*
	* To iterate through all the dictionary entries, you can set the matching key
	* to the null string "" and set the AV_DICT_IGNORE_SUFFIX flag.
	*
	* @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);

	/**
	* 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.
	*
	* @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 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.
	* @param dst pointer to a pointer to a AVDictionary struct. If *dst is NULL,
	* this function will allocate a struct for you and put it in *dst
	* @param src pointer to source AVDictionary struct
	* @param flags flags to use when setting entries in *dst
	* @note metadata is read using the AV_DICT_IGNORE_SUFFIX flag
	* @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 ('\').
	*
	* @param[in] m 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
	* @warning Separators cannot be neither '\\' nor '\0'. They also cannot be the same.
	*/
	int av_dict_get_string(const AVDictionary m, char *buffer,
	const char key_val_sep, const char pairs_sep);

	/**
	* @}
	*/

	#endif /* AVUTIL_DICT_H */