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/** \file     UnitPartitioner.h

 *  \brief    Provides a class for partitioning management

 */

#include "UnitPartitioner.h"

#include "CodingStructure.h"

#include "Unit.h"

#include "Slice.h"

#include "UnitTools.h"

#include "Picture.h"

//! \ingroup CommonLib

//! \{

namespace vvenc {

PartLevel::PartLevel()

: split               ( CU_DONT_SPLIT )

, parts               (               )

, idx                 ( 0u            )

, checkdIfImplicit    ( false         )

, isImplicit          ( false         )

, implicitSplit       ( CU_DONT_SPLIT )

, firstSubPartSplit   ( CU_DONT_SPLIT )

, canQtSplit          ( true          )

, qgEnable            ( true          )

, qgChromaEnable      ( true          )

, modeType            ( MODE_TYPE_ALL )

{

}

void PartLevel::init()

{

  split               = CU_DONT_SPLIT;

  idx                 = 0u;

  checkdIfImplicit    = false;

  isImplicit          = false;

  implicitSplit       = CU_DONT_SPLIT;

  firstSubPartSplit   = CU_DONT_SPLIT;

  canQtSplit          = true;

  qgEnable            = true;

  qgChromaEnable      = true;

  modeType            = MODE_TYPE_ALL;

  numParts            = 0;

}

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

// Partitioner class

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

SplitSeries Partitioner::getSplitSeries() const

{

  SplitSeries splitSeries = 0;

  SplitSeries depth = 0;

  for( const auto &level : m_partStack )

  {

    if( level.split == CTU_LEVEL ) continue;

    else splitSeries += static_cast< SplitSeries >( level.split ) << ( depth * SPLIT_DMULT );

    depth++;

  }

  return splitSeries;

}

ModeTypeSeries Partitioner::getModeTypeSeries() const

{

  ModeTypeSeries modeTypeSeries = 0;

  int depth = 0;

  for( const auto &level : m_partStack )

  {

    if( level.split == CTU_LEVEL ) continue;

    else modeTypeSeries += static_cast<int>(level.modeType) << (depth * 3);

    depth++;

  }

  return modeTypeSeries;

}

bool Partitioner::isSepTree( const CodingStructure &cs )

{

  return treeType != TREE_D || CS::isDualITree( cs );

}

void Partitioner::setCUData( CodingUnit& cu )

{

  cu.depth       = currDepth;

  cu.btDepth     = currBtDepth;

  cu.mtDepth     = currMtDepth;

  cu.qtDepth     = currQtDepth;

  cu.splitSeries = getSplitSeries();

  cu.modeTypeSeries = getModeTypeSeries();

  cu.treeType    = treeType; 

  cu.modeType    = modeType; 

}

void Partitioner::copyState( const Partitioner& other )

{

  m_partStack = other.m_partStack;

  currBtDepth = other.currBtDepth;

  currQtDepth = other.currQtDepth;

  currDepth   = other.currDepth;

  currMtDepth = other.currMtDepth;

  currTrDepth = other.currTrDepth;

  currSubdiv  = other.currSubdiv;

  currQgPos   = other.currQgPos;

  currQgChromaPos = other.currQgChromaPos;

  currImplicitBtDepth

              = other.currImplicitBtDepth;

  chType      = other.chType;

#ifdef _DEBUG

  m_currArea  = other.m_currArea;

#endif

}

void Partitioner::setMaxMinDepth( unsigned& minDepth, unsigned& maxDepth, const CodingStructure& cs, int QtbttSpeedUp, bool MergeFlag) const

{

  unsigned          stdMinDepth = 0;

  unsigned          stdMaxDepth = cs.pcv->getMaxDepth( cs.slice->sliceType, chType );

  const Position    pos         = currArea().blocks[chType].pos();

  const unsigned    curSliceIdx = cs.slice->independentSliceIdx;

  const unsigned    curTileIdx  = cs.pps->getTileIdx( currArea().lumaPos() );

  const CodingUnit* cuLeft        = cs.getCURestricted( pos.offset( -1,                               0 ), pos, curSliceIdx, curTileIdx, chType, treeType );

  const CodingUnit* cuBelowLeft   = cs.getCURestricted( pos.offset( -1, currArea().blocks[chType].height), pos, curSliceIdx, curTileIdx, chType, treeType );

  const CodingUnit* cuAbove       = cs.getCURestricted( pos.offset(  0,                              -1 ), pos, curSliceIdx, curTileIdx, chType, treeType );

  const CodingUnit* cuAboveRight  = cs.getCURestricted( pos.offset( currArea().blocks[chType].width, -1 ), pos, curSliceIdx, curTileIdx, chType, treeType );

  minDepth = stdMaxDepth;

  maxDepth = stdMinDepth;

  if( cuLeft )

  {

    minDepth = std::min<unsigned>( minDepth, cuLeft->qtDepth );

    maxDepth = std::max<unsigned>( maxDepth, cuLeft->qtDepth );

  }

  else

  {

    minDepth = stdMinDepth;

    maxDepth = stdMaxDepth;

  }

  if( cuBelowLeft )

  {

    minDepth = std::min<unsigned>( minDepth, cuBelowLeft->qtDepth );

    maxDepth = std::max<unsigned>( maxDepth, cuBelowLeft->qtDepth );

  }

  else

  {

    minDepth = stdMinDepth;

    maxDepth = stdMaxDepth;

  }

  if( cuAbove )

  {

    minDepth = std::min<unsigned>( minDepth, cuAbove->qtDepth );

    maxDepth = std::max<unsigned>( maxDepth, cuAbove->qtDepth );

  }

  else

  {

    minDepth = stdMinDepth;

    maxDepth = stdMaxDepth;

  }

  if( cuAboveRight )

  {

    minDepth = std::min<unsigned>( minDepth, cuAboveRight->qtDepth );

    maxDepth = std::max<unsigned>( maxDepth, cuAboveRight->qtDepth );

  }

  else

  {

    minDepth = stdMinDepth;

    maxDepth = stdMaxDepth;

  }

  minDepth = ( minDepth >= 1 ? minDepth - 1 : 0 );

  maxDepth = std::min<unsigned>( stdMaxDepth, maxDepth + 1 );

  if((QtbttSpeedUp >> 2) && (cs.slice->TLayer > 0) && ((cs.area.Y().width >= 8) || (cs.area.Y().height >= 8)))

  {

    int minDepthCur = stdMaxDepth;

    int maxDepthCur = stdMinDepth;

    int amountN = 0;

    for (int n = 0; n < 3; n++)

    {

      const CodingUnit* cuNeigh = (n==0)?cs.getCURestricted(pos.offset(-1, -1), pos, curSliceIdx, curTileIdx, chType, treeType): (n==1)? cuAbove : cuLeft;

      if (cuNeigh)

      {

        amountN++;

        minDepthCur = std::min<unsigned>(minDepthCur, cuNeigh->qtDepth);

        maxDepthCur = std::max<unsigned>(maxDepthCur, cuNeigh->qtDepth);

      }

    }

    if (amountN)

    {

      minDepthCur = (minDepthCur >= 1 ? minDepthCur - 1 : 0);

      maxDepthCur = std::min<unsigned>(stdMaxDepth, maxDepthCur + 1);

      maxDepth = std::min<unsigned>(maxDepthCur, maxDepth);

      minDepth = std::max<unsigned>(minDepthCur, minDepth);

    }

  }

  if (!cs.slice->isIntra() && (QtbttSpeedUp & 3))

  {

    bool doMin_SCC = !(((QtbttSpeedUp & 3) == 2) && (cs.area.Y().width < cs.pcv->maxCUSize));

    bool LimitDepths = (QtbttSpeedUp & 2) ? (MergeFlag == 0) : (cs.area.Y().width >= cs.pcv->maxCUSize);

    if (LimitDepths && cuAbove && cuLeft && (cuLeft->qtDepth == cuAbove->qtDepth))

    {

      int minDepthCur = cuAbove->qtDepth;

      int maxDepthCur = cuAbove->qtDepth;

      minDepthCur = (minDepthCur > 0) ? (minDepthCur - 1) : 0;

      maxDepthCur = (maxDepthCur < stdMaxDepth) ? (maxDepthCur + 1) : maxDepthCur;

      maxDepth = std::min<unsigned>(maxDepthCur, maxDepth);

      minDepth = std::max<unsigned>(minDepthCur, minDepth);

    }

    else if (doMin_SCC && LimitDepths && cuAbove && cuLeft)

    {

      int minDepthCur = cuAbove->qtDepth;

      int maxDepthCur = cuAbove->qtDepth;

      minDepthCur = (minDepthCur > 0) ? (minDepthCur - 1) : 0;

      maxDepthCur = (maxDepthCur < stdMaxDepth) ? (maxDepthCur + 1) : maxDepthCur;

      if ((cuLeft->qtDepth > maxDepthCur) && ((cuLeft->qtDepth - 1) >= maxDepthCur))

      {

        minDepthCur += 1;

        maxDepthCur += 1;

      }

      else if ((cuLeft->qtDepth < minDepthCur) && ((cuLeft->qtDepth + 1) <= minDepthCur))

      {

        maxDepthCur -= 1;

        minDepthCur -= 1;

      }

      maxDepth = std::min<unsigned>(maxDepthCur, maxDepth);

      minDepth = std::max<unsigned>(minDepthCur, minDepth);

    }

    if ((QtbttSpeedUp & 2) && MergeFlag && (maxDepth == 4) && (cs.area.Y().width <= 16))

    {

      maxDepth = 3;

      minDepth = (minDepth == 3)? 2: minDepth;

    }

  }

}

void Partitioner::initCtu( const UnitArea& ctuArea, const ChannelType _chType, const Slice& slice )

{

#if _DEBUG

  m_currArea = ctuArea;

#endif

  currDepth   = 0;

  currTrDepth = 0;

  currBtDepth = 0;

  currMtDepth = 0;

  currQtDepth = 0;

  currSubdiv  = 0;

  currQgPos   = ctuArea.lumaPos();

  currQgChromaPos = ctuArea.chromaFormat != CHROMA_400 ? ctuArea.chromaPos() : Position();

  currImplicitBtDepth = 0;

  chType      = _chType;

  const PreCalcValues& pcv = *slice.pps->pcv;

  maxBTD      = pcv.getMaxMTTDepth( slice, chType );

  maxBtSize   = pcv.getMaxBtSize  ( slice, chType );

  minTSize    = pcv.getMinTSize   ( slice, chType );

  maxTtSize   = pcv.getMaxTtSize  ( slice, chType );

  minQtSize   = pcv.getMinQtSize  ( slice, chType );

  m_partBufIdx = 1;

  m_partStack.resize_noinit( 1 );

  m_partStack.back().init();

  m_partStack.back().split = CTU_LEVEL;

  m_partStack.back().parts = m_partBuf;

  m_partStack.back().parts[0] = ctuArea;

  m_partStack.back().numParts = 1;

  treeType = TREE_D;

  modeType = MODE_TYPE_ALL;

}

void Partitioner::splitCurrArea( const PartSplit split, const CodingStructure& cs )

{

  if ((split != TU_1D_HORZ_SPLIT) && (split != TU_1D_VERT_SPLIT))

  {

    CHECKD(!canSplit(split, cs), "Trying to apply a prohibited split!");

  }

  bool isImplicit = isSplitImplicit( split, cs );

  bool canQtSplit = canSplit( CU_QUAD_SPLIT, cs );

  bool qgEnable = currQgEnable();

  bool qgChromaEnable = currQgChromaEnable();

  const UnitArea& area = currArea();

  m_partStack.resize_noinit( m_partStack.size() + 1 );

  PartLevel& back = m_partStack.back();

  back.init();

  back.split = split;

  back.parts = &m_partBuf[m_partBufIdx];

  int numParts;

  CHECK( m_partBufIdx > partBufSize, "Partition buffer overflow" );

  switch( split )

  {

  case CU_QUAD_SPLIT:

    numParts = PartitionerImpl::getCUSubPartitions( back.parts, area, cs, split );

    back.modeType = modeType;

    break;

  case CU_HORZ_SPLIT:

  case CU_VERT_SPLIT:

    numParts = PartitionerImpl::getCUSubPartitions( back.parts, area, cs, split );

    back.modeType = modeType;

    break;

  case CU_TRIH_SPLIT:

  case CU_TRIV_SPLIT:

    numParts = PartitionerImpl::getCUSubPartitions( back.parts, area, cs, split );

    back.modeType = modeType;

    break;

  case TU_MAX_TR_SPLIT:

    numParts = PartitionerImpl::getMaxTuTiling( back.parts, area, cs );

    break;

  case SBT_VER_HALF_POS0_SPLIT:

  case SBT_VER_HALF_POS1_SPLIT:

  case SBT_HOR_HALF_POS0_SPLIT:

  case SBT_HOR_HALF_POS1_SPLIT:

  case SBT_VER_QUAD_POS0_SPLIT:

  case SBT_VER_QUAD_POS1_SPLIT:

  case SBT_HOR_QUAD_POS0_SPLIT:

  case SBT_HOR_QUAD_POS1_SPLIT:

    numParts = PartitionerImpl::getSbtTuTiling( back.parts, area, cs, split );

    break;

  case TU_1D_HORZ_SPLIT:

  case TU_1D_VERT_SPLIT:

  {

    numParts = PartitionerImpl::getTUIntraSubPartitions(back.parts, area, cs, split, TREE_D);

    break;

  }

  default:

    THROW( "Unknown split mode" );

    break;

  }

  back.numParts = numParts;

  m_partBufIdx += numParts;

  CHECK( m_partBufIdx > partBufSize, "Partition buffer overflow" );

  currDepth++;

  currSubdiv++;

#if _DEBUG

  m_currArea = m_partStack.back().parts[0];

#endif

  if ((split == TU_MAX_TR_SPLIT) || (split == TU_1D_HORZ_SPLIT) || (split == TU_1D_VERT_SPLIT))

  {

    currTrDepth++;

  }

  else if( split >= SBT_VER_HALF_POS0_SPLIT && split <= SBT_HOR_QUAD_POS1_SPLIT )

  {

    currTrDepth++;

  }

  else

  {

    currTrDepth = 0;

  }

  if( split == CU_HORZ_SPLIT || split == CU_VERT_SPLIT || split == CU_TRIH_SPLIT || split == CU_TRIV_SPLIT )

  {

    currBtDepth++;

    if( isImplicit ) currImplicitBtDepth++;

    currMtDepth++;

    if( split == CU_TRIH_SPLIT || split == CU_TRIV_SPLIT )

    {

      // first and last part of triple split are equivalent to double bt split

      currBtDepth++;

      currSubdiv++;

    }

    m_partStack.back().canQtSplit = canQtSplit;

  }

  else if( split == CU_QUAD_SPLIT )

  {

    CHECK( currBtDepth > 0, "Cannot split a non-square area other than with a binary split" );

    CHECK( currMtDepth > 0, "Cannot split a non-square area other than with a binary split" );

    currMtDepth = 0;

    currBtDepth = 0;

    currQtDepth++;

    currSubdiv++;

  }

  qgEnable       &= (currSubdiv <= (cs.slice->isIntra() ? cs.slice->picHeader->cuQpDeltaSubdivIntra : cs.slice->picHeader->cuQpDeltaSubdivInter ));

  qgChromaEnable &= (currSubdiv <= (cs.slice->isIntra() ? cs.slice->picHeader->cuChromaQpOffsetSubdivIntra : cs.slice->picHeader->cuChromaQpOffsetSubdivInter ));

  m_partStack.back().qgEnable       = qgEnable;

  m_partStack.back().qgChromaEnable = qgChromaEnable;

  if (qgEnable)

    currQgPos = currArea().lumaPos();

  if (qgChromaEnable)

    currQgChromaPos = currArea().chromaPos();

}

void Partitioner::canSplit( const CodingStructure &cs, bool& canNo, bool& canQt, bool& canBh, bool& canBv, bool& canTh, bool& canTv )

{

  const PartSplit implicitSplit = m_partStack.back().checkdIfImplicit ? m_partStack.back().implicitSplit : getImplicitSplit( cs );

  canNo = canQt = canBh = canTh = canBv = canTv = true;

  bool canBtt = currMtDepth < (maxBTD + currImplicitBtDepth);

  // the minimal and maximal sizes are given in luma samples

  const CompArea&  area  = currArea().Y();

  const CompArea  *areaC = (chType == CH_C) ? &(currArea().Cb()) : nullptr;

        PartLevel& level = m_partStack.back();

  const PartSplit lastSplit = level.split;

  const PartSplit parlSplit = lastSplit == CU_TRIH_SPLIT ? CU_HORZ_SPLIT : CU_VERT_SPLIT;

  // don't allow QT-splitting below a BT split

  if( lastSplit != CTU_LEVEL && lastSplit != CU_QUAD_SPLIT ) canQt = false;

  // minQtSize is in luma samples unit

  const unsigned minQTThreshold = minQtSize >> ((area.chromaFormat == CHROMA_400) ? 0 : ((int) getChannelTypeScaleX(CH_C, area.chromaFormat) - (int) getChannelTypeScaleY(CH_C, area.chromaFormat)));

  if( area.width <= minQTThreshold )                         canQt = false;

  if( areaC && areaC->width <= MIN_DUALTREE_CHROMA_WIDTH ) canQt = false;

  if( treeType == TREE_C )

  {

    canQt = canBh = canTh = canBv = canTv = false;

    return;

  }

  if( implicitSplit != CU_DONT_SPLIT )

  {

    canNo = canTh = canTv = false;

    canBh = implicitSplit == CU_HORZ_SPLIT;

    canBv = implicitSplit == CU_VERT_SPLIT;

    if (areaC && areaC->width == 4) canBv = false;

    if( !canBh && !canBv && !canQt ) canQt = true;

    return;

  }

  if( ( lastSplit == CU_TRIH_SPLIT || lastSplit == CU_TRIV_SPLIT ) && currPartIdx() == 1 )

  {

    canBh = parlSplit != CU_HORZ_SPLIT;

    canBv = parlSplit != CU_VERT_SPLIT;

  }

  if( canBtt && ( area.width <= minTSize && area.height <= minTSize ) )

  {

    canBtt = false;

  }

  if( canBtt && ( area.width > maxBtSize || area.height > maxBtSize )

      && ( ( area.width > maxTtSize || area.height > maxTtSize ) ) )

  {

    canBtt = false;

  }

  if( !canBtt )

  {

    canBh = canTh = canBv = canTv = false;

    return;

  }

  if( area.width > maxBtSize || area.height > maxBtSize )

  {

    canBh = canBv = false;

  }

  // specific check for BT splits

  if( area.height <= minTSize )                            canBh = false;

  if( area.width > MAX_TB_SIZEY && area.height <= MAX_TB_SIZEY ) canBh = false;

  if( areaC && areaC->width * areaC->height <= MIN_DUALTREE_CHROMA_SIZE )     canBh = false;

  if( area.width <= minTSize )                              canBv = false;

  if( area.width <= MAX_TB_SIZEY && area.height > MAX_TB_SIZEY ) canBv = false;

  if (areaC && (areaC->width * areaC->height <= MIN_DUALTREE_CHROMA_SIZE || areaC->width == 4))     canBv = false;

  if( modeType == MODE_TYPE_INTER && area.width * area.height == 32 )  canBv = canBh = false;

  if( area.height <= 2 * minTSize || area.height > maxTtSize || area.width > maxTtSize )

                                                                                       canTh = false;

  if( area.width > MAX_TB_SIZEY || area.height > MAX_TB_SIZEY )  canTh = false;

  if( areaC && areaC->width * areaC->height <= MIN_DUALTREE_CHROMA_SIZE*2 )     canTh = false;

  if( area.width <= 2 * minTSize || area.width > maxTtSize || area.height > maxTtSize )

                                                                                       canTv = false;

  if( area.width > MAX_TB_SIZEY || area.height > MAX_TB_SIZEY )  canTv = false;

  if (areaC && (areaC->width * areaC->height <= MIN_DUALTREE_CHROMA_SIZE * 2 || areaC->width == 8))     canTv = false;

  if( modeType == MODE_TYPE_INTER && area.width * area.height == 64 )  canTv = canTh = false;

}

bool Partitioner::canSplit( const PartSplit split, const CodingStructure &cs )

{

  const CompArea area       = currArea().Y();

  const unsigned maxTrSize  = cs.sps->getMaxTbSize();

  bool canNo, canQt, canBh, canTh, canBv, canTv;

  canSplit( cs, canNo, canQt, canBh, canBv, canTh, canTv );

  switch( split )

  {

  case CTU_LEVEL:

    THROW( "Checking if top level split is possible" );

    return true;

    break;

  case TU_MAX_TR_SPLIT:

    return area.width > maxTrSize || area.height > maxTrSize;

    break;

  case SBT_VER_HALF_POS0_SPLIT:

  case SBT_VER_HALF_POS1_SPLIT:

  case SBT_HOR_HALF_POS0_SPLIT:

  case SBT_HOR_HALF_POS1_SPLIT:

  case SBT_VER_QUAD_POS0_SPLIT:

  case SBT_VER_QUAD_POS1_SPLIT:

  case SBT_HOR_QUAD_POS0_SPLIT:

  case SBT_HOR_QUAD_POS1_SPLIT:

    return currTrDepth == 0;

    break;

  case CU_QUAD_SPLIT:

    return canQt;

  case CU_DONT_SPLIT:

    return canNo;

  case CU_HORZ_SPLIT:

    return canBh;

  case CU_VERT_SPLIT:

    return canBv;

  case CU_TRIH_SPLIT:

    return canTh;

  case CU_TRIV_SPLIT:

    return canTv;

  case CU_MT_SPLIT:

    return ( canBh || canTh || canBv || canTv );

  case CU_BT_SPLIT:

    return ( canBh || canBv );

  break;

  default:

    THROW( "Unknown split mode" );

    return false;

    break;

  }

  return true;

}

bool Partitioner::canSplitISP(const PartSplit split, const CodingStructure& cs, CodingUnit& cu)

{

  // const PartSplit implicitSplit = getImplicitSplit(cs);

  const UnitArea& area = currArea();

  switch (split)

  {

  case TU_1D_HORZ_SPLIT:

  {

    return area.lheight() == cu.lheight();

  }

  case TU_1D_VERT_SPLIT:

  {

    return area.lwidth() == cu.lwidth();

  }

  case TU_MAX_TR_SPLIT:

  {

    // this split is performed implicitly with the other splits

    return false;

  }

  default: THROW("Unknown 1-D split mode"); break;

  }

}

bool Partitioner::isSplitImplicit( const PartSplit split, const CodingStructure &cs )

{

  return split == getImplicitSplit( cs );

}

PartSplit Partitioner::getImplicitSplit( const CodingStructure &cs )

{

  if( m_partStack.back().checkdIfImplicit )

  {

    return m_partStack.back().implicitSplit;

  }

  PartSplit split = CU_DONT_SPLIT;

  if( split == CU_DONT_SPLIT )

  {

    const bool isBlInPic = cs.picture->Y().contains( currArea().Y().bottomLeft() );

    const bool isTrInPic = cs.picture->Y().contains( currArea().Y().topRight() );

    const CompArea& area      = currArea().Y();

    const bool isBtAllowed    = area.width <= maxBtSize && area.height <= maxBtSize && currMtDepth < (maxBTD + currImplicitBtDepth);

    // minQtSize is in luma samples unit

    const unsigned minQTThreshold = minQtSize >> ((area.chromaFormat == CHROMA_400) ? 0 : ((int) getChannelTypeScaleX(CH_C, area.chromaFormat) - (int) getChannelTypeScaleY(CH_C, area.chromaFormat)));

    const bool isQtAllowed    = area.width > minQTThreshold && currBtDepth == 0;

    if( !isBlInPic && !isTrInPic && isQtAllowed )

    {

      split = CU_QUAD_SPLIT;

    }

    else if( !isBlInPic && isBtAllowed && area.width <= MAX_TB_SIZEY )

    {

      split = CU_HORZ_SPLIT;

    }

    else if( !isTrInPic && isBtAllowed && area.height <= MAX_TB_SIZEY )

    {

      split = CU_VERT_SPLIT;

    }

    else if( !isBlInPic || !isTrInPic )

    {

      split = CU_QUAD_SPLIT;

    }

    if (CS::isDualITree(cs) && (currArea().Y().width > 64 || currArea().Y().height > 64))

    {

      split = CU_QUAD_SPLIT;

    }

    if( (!isBlInPic || !isTrInPic) && split == CU_DONT_SPLIT )

    {

      split = CU_QUAD_SPLIT;

    }

  }

  m_partStack.back().checkdIfImplicit = true;

  m_partStack.back().isImplicit = split != CU_DONT_SPLIT;

  m_partStack.back().implicitSplit = split;

  return split;

}

void Partitioner::exitCurrSplit()

{

  const PartSplit currSplit = m_partStack.back().split;

  const int       currIndex = m_partStack.back().idx;

  const int       numParts  = m_partStack.back().numParts;

  m_partStack.pop_back();

  m_partBufIdx -= numParts;

  CHECK( currDepth == 0, "depth is '0', although a split was performed" );

  currDepth--;

  currSubdiv--;

  if( currQgEnable() )

    currQgPos = currArea().lumaPos();

  if( currArea().chromaFormat != CHROMA_400 && currQgChromaEnable() )

    currQgChromaPos = currArea().chromaPos();

#if _DEBUG

  m_currArea = m_partStack.back().parts[m_partStack.back().idx];

#endif

  if( currSplit == CU_HORZ_SPLIT || currSplit == CU_VERT_SPLIT || currSplit == CU_TRIH_SPLIT || currSplit == CU_TRIV_SPLIT )

  {

    CHECK( !m_partStack.back().checkdIfImplicit, "Didn't check if the current split is implicit" );

    CHECK( currBtDepth == 0, "BT depth is '0', athough a BT split was performed" );

    CHECK( currMtDepth == 0, "MT depth is '0', athough a BT split was performed" );

    currMtDepth--;

    if( m_partStack.back().isImplicit ) currImplicitBtDepth--;

    currBtDepth--;

    if( ( currSplit == CU_TRIH_SPLIT || currSplit == CU_TRIV_SPLIT ) && currIndex != 1 )

    {

      CHECK( currBtDepth == 0, "BT depth is '0', athough a TT split was performed" );

      currBtDepth--;

      currSubdiv--;

    }

  }

  else if( currSplit == TU_MAX_TR_SPLIT )

  {

    CHECK( currTrDepth == 0, "TR depth is '0', although a TU split was performed" );

    currTrDepth--;

  }

  else if( currSplit >= SBT_VER_HALF_POS0_SPLIT && currSplit <= SBT_HOR_QUAD_POS1_SPLIT )

  {

    CHECK( currTrDepth == 0, "TR depth is '0', although a TU split was performed" );

    currTrDepth--;

  }

  else if ((currSplit == TU_1D_HORZ_SPLIT) || (currSplit == TU_1D_VERT_SPLIT))

  {

    CHECK(currTrDepth == 0, "TR depth is '0', although a TU split was performed");

    currTrDepth--;

  }

  else

  {

    CHECK( currTrDepth > 0, "RQT found with QTBT partitioner" );

    CHECK( currQtDepth == 0, "QT depth is '0', although a QT split was performed" );

    currQtDepth--;

    currSubdiv--;

  }

}

bool Partitioner::nextPart( const CodingStructure &cs, bool autoPop /*= false*/ )

{

  const Position& prevPos = currArea().blocks[chType].pos();

  unsigned currIdx = ++m_partStack.back().idx;

  m_partStack.back().checkdIfImplicit = false;

  m_partStack.back().isImplicit = false;

  if( currIdx == 1 )

  {

    const CodingUnit* prevCU = cs.getCU( prevPos, chType, treeType );

    m_partStack.back().firstSubPartSplit = prevCU ? CU::getSplitAtDepth( *prevCU, currDepth ) : CU_DONT_SPLIT;

  }

  if( currIdx < m_partStack.back().numParts )

  {

    if( m_partStack.back().split == CU_TRIH_SPLIT || m_partStack.back().split == CU_TRIV_SPLIT )

    {

      // adapt the current bt depth

      if( currIdx == 1 ) currBtDepth--;

      else               currBtDepth++;

      if( currIdx == 1 ) currSubdiv--;

      else               currSubdiv++;

    }

  if( currQgEnable() )

    currQgPos = currArea().lumaPos();

  if( currQgChromaEnable() )

    currQgChromaPos = currArea().chromaPos();

#if _DEBUG

    m_currArea = m_partStack.back().parts[currIdx];

#endif

    return true;

  }

  else

  {

    if( autoPop ) exitCurrSplit();

    return false;

  }

}

bool Partitioner::hasNextPart()

{

  return ( ( m_partStack.back().idx + 1 ) < m_partStack.back().numParts );

}

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

// Partitioner methods describing the actual partitioning logic

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

int PartitionerImpl::getCUSubPartitions( Partitioning& dst, const UnitArea &cuArea, const CodingStructure &cs, const PartSplit _splitType )

{

  const PartSplit splitType = _splitType;

  if( splitType == CU_QUAD_SPLIT )

  {

    Partitioning& sub = dst;

    for( uint32_t i = 0; i < 4; i++ )

    {

      sub[i] = cuArea;

      for( auto &blk : sub[i].blocks )

      {

        blk.height >>= 1;

        blk.width  >>= 1;

        if( i >= 2 ) blk.y += blk.height;

        if( i &  1 ) blk.x += blk.width;

      }

    }

    return 4;

  }

  else if( splitType == CU_HORZ_SPLIT )

  {

    Partitioning& sub = dst;

    for (uint32_t i = 0; i < 2; i++)

    {

      sub[i] = cuArea;

      for (auto &blk : sub[i].blocks)

      {

        blk.height >>= 1;

        if (i == 1) blk.y += blk.height;

      }

    }

    return 2;

  }

  else if( splitType == CU_VERT_SPLIT )

  {

    Partitioning& sub = dst;

    for( uint32_t i = 0; i < 2; i++ )

    {

      sub[i] = cuArea;

      for( auto &blk : sub[i].blocks )

      {

        blk.width >>= 1;

        if( i == 1 ) blk.x += blk.width;

      }

    }

    return 2;

  }

  else if( splitType == CU_TRIH_SPLIT )

  {

    Partitioning& sub = dst;