/*

 *

 * 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



/**

 * @defgroup dict_api Public Dictionary API

 * @{

 * 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

 * 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);

 *

 * AVDictionaryEntry *t = NULL;

 * 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

#define AV_DICT_IGNORE_SUFFIX   2

#define AV_DICT_DONT_STRDUP_KEY 4   /**< Take ownership of a key that's been

                                         allocated with av_malloc() and children. */

#define AV_DICT_DONT_STRDUP_VAL 8   /**< Take ownership of a value that's been

                                         allocated with av_malloc() and chilren. */

#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. */



typedef struct {

    char *key;

    char *value;

} AVDictionaryEntry;



typedef struct AVDictionary AVDictionary;



/**

 * Get a dictionary entry with matching key.

 *

 * @param prev Set to the previous matching element to find the next.

 *             If set to NULL the first matching element is returned.

 * @param flags Allows case as well as suffix-insensitive comparisons.

 * @return Found entry or NULL, changing key or value leads to undefined behavior.

 */

AVDictionaryEntry *

av_dict_get(AVDictionary *m, const char *key, const AVDictionaryEntry *prev, int flags);



/**

 * Set the given entry in *pm, overwriting an existing entry.

 *

 * @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 be av_strduped depending on flags)

 * @param value entry value to add to *pm (will be av_strduped depending on flags).

 *        Passing a NULL value will cause an existing tag 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);



/**

 * 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

 */

void av_dict_copy(AVDictionary **dst, AVDictionary *src, int flags);



/**

 * Free all the memory allocated for an AVDictionary struct

 * and all keys and values.

 */

void av_dict_free(AVDictionary **m);



#endif // AVUTIL_DICT_H

