unit ffm.dict;

{$i ffmpeg.inc}

interface

(*
  *
  * This file is part of ffm.
  *
  * 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.
*)

(*
  * @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
  * 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
  *
*)
const
  AV_DICT_MATCH_CASE = 1;
  AV_DICT_IGNORE_SUFFIX = 2;
  AV_DICT_DONT_STRDUP_KEY = 4; // **< Take ownership of a key that's been
  // allocated with av_malloc() and children. */
  AV_DICT_DONT_STRDUP_VAL = 8; // **< Take ownership of a value that's been
  // allocated with av_malloc() and chilren. */
  AV_DICT_DONT_OVERWRITE = 16;
  /// < Don't overwrite existing entries.
  AV_DICT_APPEND = 32; // **< If the entry already exists, append to it.  Note that no
  // delimiter is added, the strings are simply concatenated. */

type
  pAVDictionaryEntry = ^TAVDictionaryEntry;

  TAVDictionaryEntry = { packed } record
    key: pAnsiChar;
    value: pAnsiChar;
  end;

  pAVDictionary = ^TAVDictionary;
  ppAVDictionary = ^pAVDictionary;

  TAVDictionary = { packed } record
  end;

  (*
    * 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);
function av_dict_get(m: pAVDictionary; const key: pAnsiChar; const prev: pAVDictionaryEntry; flags: Integer): pAVDictionaryEntry; cdecl;

(*
  * 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.
  *
  * @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 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);
function av_dict_set(Var pm: pAVDictionary; const key: pAnsiChar; const value: pAnsiChar; flags: Integer): Integer; cdecl;

(*
  * Parse the key/value pairs list and add to a 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
*)
// 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);
procedure av_dict_free(Var m: pAVDictionary); cdecl;

implementation

uses ffm.lib;

function av_dict_get; external avutil_dll;
procedure av_dict_free; external avutil_dll;
function av_dict_set; external avutil_dll;

end.