/*

  * seek utility functions for use within format handlers

  *
  * Copyright (c) 2009 Ivan Schreter
  *
  * 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
  */
 
 #ifndef AVFORMAT_SEEK_H
 #define AVFORMAT_SEEK_H
 
 #include "avformat.h"
 

 /**
  * structure to store parser state of one AVStream
  */
 typedef struct AVParserStreamState {
     // saved members of AVStream
     AVCodecParserContext   *parser;
     AVPacket                cur_pkt;
     int64_t                 last_IP_pts;
     int64_t                 cur_dts;
     int64_t                 reference_dts;
     const uint8_t          *cur_ptr;
     int                     cur_len;
     int                     probe_packets;
 } AVParserStreamState;
 
 /**
  * structure to store parser state of AVFormat
  */
 typedef struct AVParserState {
     int64_t         fpos;                   ///< file position at the time of call
 
     // saved members of AVFormatContext
     AVStream       *cur_st;                 ///< current stream.
     AVPacketList   *packet_buffer;          ///< packet buffer of original state
     AVPacketList   *raw_packet_buffer;      ///< raw packet buffer of original state
     int raw_packet_buffer_remaining_size;   ///< remaining space in raw_packet_buffer
 
     // saved info for streams
     int                  nb_streams;        ///< number of streams with stored state
     AVParserStreamState *stream_states;     ///< states of individual streams (array)
 } AVParserState;

 
 /**

  * Search for the sync point of all active streams.

  *

  * This routine is not supposed to be called directly by a user application,

  * but by demuxers.
  *

  * A sync point is defined as a point in stream, such that, when decoding start
  * from this point, the decoded output of all streams synchronizes closest
  * to the given timestamp ts. This routine also takes timestamp limits into account.
  * Thus, the output will synchronize no sooner than ts_min and no later than ts_max.

  *

  * @param stream_index stream index for time base reference of timestamps
  * @param pos          approximate position where to start searching for key frames
  * @param min_ts       minimum allowed timestamp (position, if AVSEEK_FLAG_BYTE set)
  * @param ts           target timestamp (or position, if AVSEEK_FLAG_BYTE set in flags)
  * @param max_ts       maximum allowed timestamp (position, if AVSEEK_FLAG_BYTE set)
  * @param flags        if AVSEEK_FLAG_ANY is set, seek to any frame, otherwise only
  *                     to a keyframe. If AVSEEK_FLAG_BYTE is set, search by
  *                     position, not by timestamp.
  * @return -1 if no such sync point could be found, otherwise stream position
  *                     (stream is repositioned to this position)

  */
 int64_t ff_gen_syncpoint_search(AVFormatContext *s,
                                 int stream_index,
                                 int64_t pos,
                                 int64_t min_ts,
                                 int64_t ts,
                                 int64_t max_ts,
                                 int flags);
 
 /**
  * Store current parser state and file position.
  *

  * This function can be used by demuxers before a destructive seeking algorithm
  * to store the parser state. Depending on the outcome of the seek, either the original
  * state can be restored or the new state kept and the original state freed.

  *

  * @note As a side effect, the original parser state is reset, since structures
  *       are relinked to the stored state instead of being deeply-copied (for
  *       performance reasons and to keep the code simple).

  *

  * @param s context from which to save state
  * @return parser state object or NULL if memory could not be allocated

  */
 AVParserState *ff_store_parser_state(AVFormatContext *s);
 
 /**
  * Restore previously saved parser state and file position.
  *
  * Saved state will be invalidated and freed by this call, since internal

  * structures will be relinked back to the stored state instead of being

  * deeply-copied.
  *

  * @param s     context to which to restore state (same as used for storing state)
  * @param state state to restore

  */
 void ff_restore_parser_state(AVFormatContext *s, AVParserState *state);
 
 /**
  * Free previously saved parser state.
  *

  * @param s     context to which the state belongs (same as used for storing state)
  * @param state state to free

  */
 void ff_free_parser_state(AVFormatContext *s, AVParserState *state);
 
 #endif /* AVFORMAT_SEEK_H */