/* -----------------------------------------------------------------------------

The copyright in this software is being made available under the Clear BSD

License, included below. No patent rights, trademark rights and/or 

other Intellectual Property Rights other than the copyrights concerning 

the Software are granted under this license.

The Clear BSD License

Copyright (c) 2018-2026, Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. & The VVdeC Authors.

All rights reserved.

Redistribution and use in source and binary forms, with or without modification,

are permitted (subject to the limitations in the disclaimer below) 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 copyright holder nor the names of its

     contributors may be used to endorse or promote products derived from this

     software without specific prior written permission.

NO EXPRESS OR IMPLIED LICENSES TO ANY PARTY'S PATENT RIGHTS ARE GRANTED BY

THIS LICENSE. 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.

------------------------------------------------------------------------------------------- */

/** \file     DecSlice.cpp

    \brief    slice decoder class

*/

#include "CABACReader.h"

#include "DecSlice.h"

#include "Picture.h"

#include "Slice.h"

#include "CommonLib/dtrace_next.h"

#include "CommonLib/TimeProfiler.h"

#include "CommonLib/AdaptiveLoopFilter.h"

#include <vector>

namespace vvdec

{

//////////////////////////////////////////////////////////////////////

// Construction/Destruction

//////////////////////////////////////////////////////////////////////

void DecSlice::parseSlice( Slice* slice, InputBitstream* bitstream, int threadId )

{

  PROFILER_SCOPE_AND_STAGE_EXT( 1, g_timeProfiler, P_CONTROL_PARSE_DERIVE_LL, *slice->getPic()->cs, CH_L );

  const unsigned numSubstreams = slice->getNumberOfSubstreamSizes() + 1;

  // Table of extracted substreams.

  std::vector<std::unique_ptr<InputBitstream>> ppcSubstreams( numSubstreams );

  for( unsigned idx = 0; idx < numSubstreams; idx++ )

  {

    ppcSubstreams[idx] = bitstream->extractSubstream( idx + 1 < numSubstreams ? ( slice->getSubstreamSize( idx ) << 3 ) : bitstream->getNumBitsLeft() );

  }

  const SPS* sps = slice->getSPS();

  Picture*   pic = slice->getPic();

  // setup coding structure

  CodingStructure& cs = *pic->cs;

  cs.chromaQpAdj      = 0;

  const unsigned widthInCtus       = cs.pcv->widthInCtus;

  const bool     wavefrontsEnabled = cs.sps->getEntropyCodingSyncEnabledFlag();

  const bool     entryPointPresent = cs.sps->getEntryPointsPresentFlag();

  AdaptiveLoopFilter::reconstructCoeffAPSs( *slice );

  CABACReader cabacReader;

  cabacReader.initBitstream( ppcSubstreams[0].get() );

  cabacReader.initCtxModels( *slice );

  // Quantization parameter

  int prevQP[2] = { slice->getSliceQp(), slice->getSliceQp() };

  CHECK( prevQP[0] == std::numeric_limits<int>::max(), "Invalid previous QP" );

  DTRACE( g_trace_ctx, D_HEADER, "=========== POC: %d ===========\n", slice->getPOC() );

  unsigned subStrmId = 0;

  for( unsigned ctuIdx = 0; ctuIdx < slice->getNumCtuInSlice(); ctuIdx++ )

  {

    const unsigned  ctuRsAddr       = slice->getCtuAddrInSlice(ctuIdx);

    const unsigned  ctuXPosInCtus   = ctuRsAddr % widthInCtus;

    const unsigned  ctuYPosInCtus   = ctuRsAddr / widthInCtus;

    const unsigned  tileColIdx      = slice->getPPS()->ctuToTileCol( ctuXPosInCtus );

    const unsigned  tileRowIdx      = slice->getPPS()->ctuToTileRow( ctuYPosInCtus );

    const unsigned  tileXPosInCtus  = slice->getPPS()->getTileColumnBd( tileColIdx );

    const unsigned  tileYPosInCtus  = slice->getPPS()->getTileRowBd( tileRowIdx );

    const unsigned  tileColWidth    = slice->getPPS()->getTileColumnWidth( tileColIdx );

    const unsigned  tileRowHeight   = slice->getPPS()->getTileRowHeight( tileRowIdx );

    const unsigned  tileIdx         = slice->getPPS()->getTileIdx( ctuXPosInCtus, ctuYPosInCtus);

    const unsigned  maxCUSize       = sps->getMaxCUWidth();

    const Position pos( ctuXPosInCtus*maxCUSize, ctuYPosInCtus*maxCUSize) ;

    const UnitArea ctuArea( cs.area.chromaFormat, Area( pos.x, pos.y, maxCUSize, maxCUSize ) );

    // these checks only work, since we wait for the previous slice to finish parsing

    CHECK( ctuXPosInCtus > 0 && cs.getCtuData( ctuRsAddr - 1           ).slice == nullptr, "CTU left not available RS:" << ctuRsAddr - 1 );

    CHECK( ctuYPosInCtus > 0 && cs.getCtuData( ctuRsAddr - widthInCtus ).slice == nullptr, "CTU above not available RS:" << ctuRsAddr - widthInCtus );

    DTRACE_UPDATE( g_trace_ctx, std::make_pair( "ctu", ctuRsAddr ) );

    cabacReader.initBitstream( ppcSubstreams[subStrmId].get() );

    // set up CABAC contexts' state for this CTU

    if( ctuXPosInCtus == tileXPosInCtus && ctuYPosInCtus == tileYPosInCtus )

    {

      if( ctuIdx != 0 ) // if it is the first CTU, then the entropy coder has already been reset

      {

        cabacReader.initCtxModels( *slice );

      }

      prevQP[0] = prevQP[1] = slice->getSliceQp();

    }

    else if( ctuXPosInCtus == tileXPosInCtus && wavefrontsEnabled )

    {

      // Synchronize cabac probabilities with upper-right CTU if it's available and at the start of a line.

      if( ctuIdx != 0 ) // if it is the first CTU, then the entropy coder has already been reset

      {

        cabacReader.initCtxModels( *slice );

      }

      if( cs.getCURestricted( pos.offset(0, -1), pos, slice->getIndependentSliceIdx(), tileIdx, CH_L ) )

      {

        cabacReader.setCtx( m_entropyCodingSyncContextState[threadId] );

      }

      prevQP[0] = prevQP[1] = slice->getSliceQp();

    }

    //memset( cs.getCtuData( ctuRsAddr ).cuPtr, 0, sizeof( CtuData::cuPtr ) );

    CtuData& ctuData = cs.getCtuData( ctuRsAddr );

    ctuData.slice = slice;

    ctuData.pps   = slice->getPPS();

    ctuData.sps   = slice->getSPS();

    ctuData.ph    = slice->getPicHeader();

    cabacReader.coding_tree_unit( cs, slice, ctuArea, prevQP, ctuRsAddr );

    if( ctuXPosInCtus == tileXPosInCtus && wavefrontsEnabled )

    {

      m_entropyCodingSyncContextState[threadId] = cabacReader.getCtx();

    }

    if( ctuIdx == slice->getNumCtuInSlice()-1 )

    {

      unsigned binVal = cabacReader.terminating_bit();

      CHECK( !binVal, "Expecting a terminating bit" );

#if DECODER_CHECK_SUBSTREAM_AND_SLICE_TRAILING_BYTES

      cabacReader.remaining_bytes( false );

#endif

    }

    else if( ( ctuXPosInCtus + 1 == tileXPosInCtus + tileColWidth ) &&

             ( ctuYPosInCtus + 1 == tileYPosInCtus + tileRowHeight || wavefrontsEnabled ) )

    {

      // The sub-stream/stream should be terminated after this CTU.

      // (end of slice-segment, end of tile, end of wavefront-CTU-row)

      unsigned binVal = cabacReader.terminating_bit();

      CHECK( !binVal, "Expecting a terminating bit" );

      if( entryPointPresent )

      {

#if DECODER_CHECK_SUBSTREAM_AND_SLICE_TRAILING_BYTES

        cabacReader.remaining_bytes( true );

#endif

        subStrmId++;

      }

    }

#if RECO_WHILE_PARSE

    pic->ctuParsedBarrier[ctuRsAddr].unlock();

#endif

    if( ctuRsAddr + 1 == pic->cs->pcv->sizeInCtus )

    {

      Picture::PicStateEnum expected = Picture::parsing;

      pic->progress.compare_exchange_strong( expected, Picture::parsed );   // if RECO_WHILE_PARSE reconstruction can already have started, so we make sure to not overwrite that state

      pic->parseDone.unlock();

    }

  }

}

}