/* The copyright in this software is being made available under the BSD
 * License, included below. This software may be subject to other third party
 * and contributor rights, including patent rights, and no such rights are
 * granted under this license.
 *
 * Copyright (c) 2010-2012, ITU/ISO/IEC
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *  * Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *  * Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *  * Neither the name of the ITU/ISO/IEC nor the names of its contributors may
 *    be used to endorse or promote products derived from this software without
 *    specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <vector>
#include <algorithm>
#include <ostream>

#include "TLibCommon/NAL.h"
#include "TLibCommon/TComBitStream.h"
#include "NALwrite.h"

using namespace std;

//! \ingroup TLibEncoder
//! \{

static const char emulation_prevention_three_byte[] = {3};

/**
 * write nalu to bytestream out, performing RBSP anti startcode
 * emulation as required.  nalu.m_RBSPayload must be byte aligned.
 */
void write(ostream& out, OutputNALUnit& nalu)
{
  TComOutputBitstream bsNALUHeader;

  bsNALUHeader.write(0,1); // forbidden_zero_flag
  bsNALUHeader.write(nalu.m_nalRefFlag? 1 : 0, 1); // nal_ref_flag
  bsNALUHeader.write(nalu.m_nalUnitType, 6);          // nal_unit_type
  bsNALUHeader.write(nalu.m_temporalId, 3); // temporal_id
  bsNALUHeader.write(1, 5); // reserved_one_5bits
  out.write(bsNALUHeader.getByteStream(), bsNALUHeader.getByteStreamLength());

  /* write out rsbp_byte's, inserting any required
   * emulation_prevention_three_byte's */
  /* 7.4.1 ...
   * emulation_prevention_three_byte is a byte equal to 0x03. When an
   * emulation_prevention_three_byte is present in the NAL unit, it shall be
   * discarded by the decoding process.
   * The last byte of the NAL unit shall not be equal to 0x00.
   * Within the NAL unit, the following three-byte sequences shall not occur at
   * any byte-aligned position:
   *  - 0x000000
   *  - 0x000001
   *  - 0x000002
   * Within the NAL unit, any four-byte sequence that starts with 0x000003
   * other than the following sequences shall not occur at any byte-aligned
   * position:
   *  - 0x00000300
   *  - 0x00000301
   *  - 0x00000302
   *  - 0x00000303
   */
  vector<uint8_t>& rbsp   = nalu.m_Bitstream.getFIFO();
  UInt uiTileMarkerCount  = nalu.m_Bitstream.getTileMarkerLocationCount();

  for (vector<uint8_t>::iterator it = rbsp.begin(); it != rbsp.end();)
  {
    /* 1) find the next emulated 00 00 {00,01,02,03}
     * 2a) if not found, write all remaining bytes out, stop.
     * 2b) otherwise, write all non-emulated bytes out
     * 3) insert emulation_prevention_three_byte
     */
    vector<uint8_t>::iterator found = it;
    do
    {
      /* NB, end()-1, prevents finding a trailing two byte sequence */
      found = search_n(found, rbsp.end()-1, 2, 0);
      found++;
      /* if not found, found == end, otherwise found = second zero byte */
      if (found == rbsp.end())
        break;
      if (*(++found) <= 3)
        break;
    } while (true);

    UInt uiDistance = (UInt)(found - rbsp.begin());
    for ( UInt uiMrkrIdx = 0; uiMrkrIdx < uiTileMarkerCount ; uiMrkrIdx++ )
    {    
      UInt uiByteLocation   = nalu.m_Bitstream.getTileMarkerLocation( uiMrkrIdx );
      if (found != rbsp.end() && uiByteLocation > (uiDistance - 2) )
      {
        nalu.m_Bitstream.setTileMarkerLocation( uiMrkrIdx, uiByteLocation+1 );
      }
    }
    it = found;
    if (found != rbsp.end())
    {
      it = rbsp.insert(found, emulation_prevention_three_byte[0]);
    }
  }

  // Insert tile markers
  TComOutputBitstream cTileMarker;
  UInt uiMarker = 0x000002;
  cTileMarker.write(uiMarker, 24);
  for ( UInt uiInsertIdx   = 0; uiInsertIdx < uiTileMarkerCount ; uiInsertIdx++ )
  {
    UInt uiByteLocation   = nalu.m_Bitstream.getTileMarkerLocation( uiInsertIdx );
    nalu.m_Bitstream.insertAt( cTileMarker, uiByteLocation ); // 0x000002

    // update tile marker byte locations of yet to be written markers
    for ( UInt uiUpdateLOCIdx = uiInsertIdx+1; uiUpdateLOCIdx < uiTileMarkerCount; uiUpdateLOCIdx++ )
    {
      UInt uiLocation = nalu.m_Bitstream.getTileMarkerLocation( uiUpdateLOCIdx );
      nalu.m_Bitstream.setTileMarkerLocation( uiUpdateLOCIdx, uiLocation + 3 );
    }
  }
  out.write((char*)&(*rbsp.begin()), rbsp.end() - rbsp.begin());


  /* 7.4.1.1
   * ... when the last byte of the RBSP data is equal to 0x00 (which can
   * only occur when the RBSP ends in a cabac_zero_word), a final byte equal
   * to 0x03 is appended to the end of the data.
   */
  if (rbsp.back() == 0x00)
  {
    out.write(emulation_prevention_three_byte, 1);
  }
}

/**
 * Write rbsp_trailing_bits to bs causing it to become byte-aligned
 */
void writeRBSPTrailingBits(TComOutputBitstream& bs)
{
  bs.write( 1, 1 );
  bs.writeAlignZero();
}

/**
 * Copy NALU from naluSrc to naluDest
 */
void copyNaluData(OutputNALUnit& naluDest, const OutputNALUnit& naluSrc)
{
  naluDest.m_nalUnitType = naluSrc.m_nalUnitType;
  naluDest.m_nalRefFlag  = naluSrc.m_nalRefFlag;
  naluDest.m_temporalId  = naluSrc.m_temporalId;
  naluDest.m_Bitstream   = naluSrc.m_Bitstream;
}

//! \}
