/*****************************************************************************

    MPEG Video Packetizing Buffer

    Copyright(C) 2004 John Cannon <spyder@matroska.org>

    This program is free software ; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation ; either version 2 of the License, or
    (at your option) any later version.

    This program 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 General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program ; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA

 **/

#ifndef __MPEGVIDEOBUFFER_H__
#define __MPEGVIDEOBUFFER_H__

#include "Types.h"
#include "CircBuffer.h"
#include <cassert>

#define MPEG_VIDEO_PICTURE_START_CODE  0x00
#define MPEG_VIDEO_SEQUENCE_START_CODE  0xb3
#define MPEG_VIDEO_EXT_START_CODE  0xb5
#define MPEG_VIDEO_GOP_START_CODE  0xb8
#define MPEG_VIDEO_USER_START_CODE  0xb2

enum MPEG2BufferState_e {
  MPEG2_BUFFER_STATE_NEED_MORE_DATA,
  MPEG2_BUFFER_STATE_CHUNK_READY,
  MPEG2_BUFFER_STATE_EMPTY,
  MPEG2_BUFFER_INVALID
};

#define MPEG2_I_FRAME 1
#define MPEG2_P_FRAME 2
#define MPEG2_B_FRAME 3

typedef struct MPEG2SequenceHeader{
  uint32_t width;
  uint32_t height;
  float aspectRatio;
  float frameOrFieldRate;
  uint8_t profileLevelIndication;
  uint8_t progressiveSequence;

  MPEG2SequenceHeader();
}MPEG2SequenceHeader;

typedef struct MPEG2GOPHeader{
  uint8_t closedGOP;
  uint8_t brokenLink;
  uint32_t timeFrames;
  uint32_t timeSeconds;
  uint32_t timeMinutes;
  uint32_t timeHours;

  MPEG2GOPHeader();
}MPEG2GOPHeader;

#define MPEG2_PICTURE_TYPE_FRAME  0x03
#define MPEG2_PICTURE_TYPE_TOP_FIELD  0x01
#define MPEG2_PICTURE_TYPE_BOTTOM_FIELD  0x02

typedef struct MPEG2PictureHeader{
  uint32_t temporalReference;
  uint8_t frameType;
  uint32_t pictureStructure;
  uint8_t repeatFirstField;
  uint8_t topFieldFirst;
  uint8_t progressive;

  MPEG2PictureHeader();
}MPEG2PictureHeader;

class MPEGChunk{
private:
  binary * data;
  uint32_t size;
  uint8_t type;
public:
  MPEGChunk(binary* n_data, uint32_t n_size):
    data(n_data), size(n_size) {

    assert(data);
    assert(size > 4);

    type = data[3];
  }

  ~MPEGChunk(){
    if(data)
      delete [] data;
  }

  inline uint8_t GetType() const {
    return type;
  }

  inline uint32_t GetSize() const{
    return size;
  }

  binary & operator[](unsigned int i){
    return data[i];
  }

  binary & at(unsigned int i) {
    return data[i];
  }

  inline binary * GetPointer(){
    return data;
  }
};

void ParseSequenceHeader(MPEGChunk* chunk, MPEG2SequenceHeader & hdr);
bool ParsePictureHeader(MPEGChunk* chunk, MPEG2PictureHeader & hdr);
bool ParseGOPHeader(MPEGChunk* chunk, MPEG2GOPHeader & hdr);

class MPEGVideoBuffer{
private:
  CircBuffer * myBuffer;
  MPEG2BufferState_e state;
  int32_t chunkStart;
  int32_t chunkEnd;
  void UpdateState();
  int32_t FindStartCode(uint32_t startPos = 0);
public:
  MPEGVideoBuffer(uint32_t size){
    myBuffer = new CircBuffer(size);
    state = MPEG2_BUFFER_STATE_EMPTY;
    chunkStart = -1;
    chunkEnd = -1;
  }

  ~MPEGVideoBuffer(){
    delete myBuffer;
  }

  inline MPEG2BufferState_e GetState() const { return state; }

  int32_t GetFreeBufferSpace(){
    return (myBuffer->buf_capacity - myBuffer->bytes_in_buf);
  }

  void SetEndOfData(){
    chunkEnd = myBuffer->GetLength() - 1;
  }

  void ForceFinal();  //prepares the remaining data as a chunk
  MPEGChunk * ReadChunk();
  int32_t Feed(binary* data, uint32_t numBytes);
};

#endif //__MPEGVIDEOBUFFER_H__
