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/** \file     UnitPartitioner.h
 *  \brief    Provides a class for partitioning management
 */

#ifndef __UNITPARTITIONER__
#define __UNITPARTITIONER__

#include "Unit.h"

#include "CommonDef.h"

static_assert( MAX_CU_TILING_PARTITIONS >= 4, "Minimum required number of partitions for the Partitioning type is 4!" );
typedef std::vector <UnitArea> Partitioning;

//////////////////////////////////////////////////////////////////////////
// PartManager class - manages the partitioning tree
//
// contains the currently processed partitioning area (currArea)
// as well as the all partitioning decisions that led to this area
// being processed (in m_partStack).
//////////////////////////////////////////////////////////////////////////

enum PartSplit
{
  CTU_LEVEL        = 0,
  CU_QUAD_SPLIT,

  CU_HORZ_SPLIT,
  CU_VERT_SPLIT,
  CU_TRIH_SPLIT,
  CU_TRIV_SPLIT,
  TU_MAX_TR_SPLIT,
  TU_NO_ISP,
  TU_1D_HORZ_SPLIT,
  TU_1D_VERT_SPLIT,
  SBT_VER_HALF_POS0_SPLIT,
  SBT_VER_HALF_POS1_SPLIT,
  SBT_HOR_HALF_POS0_SPLIT,
  SBT_HOR_HALF_POS1_SPLIT,
  SBT_VER_QUAD_POS0_SPLIT,
  SBT_VER_QUAD_POS1_SPLIT,
  SBT_HOR_QUAD_POS0_SPLIT,
  SBT_HOR_QUAD_POS1_SPLIT,
  NUM_PART_SPLIT,
  CU_MT_SPLIT             = 1000, ///< dummy element to indicate the MT (multi-type-tree) split
  CU_BT_SPLIT             = 1001, ///< dummy element to indicate the BT split
  CU_DONT_SPLIT           = 2000  ///< dummy element to indicate no splitting
};



struct PartLevel
{
  PartSplit    split;
  Partitioning parts;
  unsigned     idx;
  bool         checkdIfImplicit;
  bool         isImplicit;
  PartSplit    implicitSplit;
  PartSplit    firstSubPartSplit;
  bool         canQtSplit;
  bool         qgEnable;
  bool         qgChromaEnable;
  int          modeType;

  PartLevel();
  PartLevel( const PartSplit _split, const Partitioning&  _parts );
  PartLevel( const PartSplit _split,       Partitioning&& _parts );
};

// set depending on max QT / BT possibilities
typedef static_vector<PartLevel, 2 * MAX_CU_DEPTH + 1> PartitioningStack;

class Partitioner
{
protected:
  PartitioningStack m_partStack;
#if _DEBUG
  UnitArea          m_currArea;
#endif

public:
  unsigned currDepth;
  unsigned currQtDepth;
  unsigned currTrDepth;
  unsigned currBtDepth;
  unsigned currMtDepth;
  unsigned currSubdiv;
  Position currQgPos;
  Position currQgChromaPos;

  unsigned currImplicitBtDepth;
  ChannelType chType;
  TreeType treeType;
  ModeType modeType;

  virtual ~Partitioner                    () { }

  const PartLevel& currPartLevel          () const { return m_partStack.back(); }
  const UnitArea&  currArea               () const { return currPartLevel().parts[currPartIdx()]; }
  const unsigned   currPartIdx            () const { return currPartLevel().idx; }
  const PartitioningStack& getPartStack   () const { return m_partStack; }
  const bool currQgEnable                 () const { return currPartLevel().qgEnable; }
  const bool currQgChromaEnable           () const { return currPartLevel().qgChromaEnable; }

  SplitSeries getSplitSeries              () const;
  ModeTypeSeries getModeTypeSeries        () const;

  virtual void initCtu                    ( const UnitArea& ctuArea, const ChannelType _chType, const Slice& slice )    = 0;
  virtual void splitCurrArea              ( const PartSplit split, const CodingStructure &cs )                          = 0;
  virtual void exitCurrSplit              ()                                                                            = 0;
  virtual bool nextPart                   ( const CodingStructure &cs, bool autoPop = false )                           = 0;
  virtual bool hasNextPart                ()                                                                            = 0;

  virtual void setCUData                  ( CodingUnit& cu );

  virtual void copyState                  ( const Partitioner& other );

public:
  virtual void canSplit                   ( const CodingStructure &cs, bool& canNo, bool& canQt, bool& canBh, bool& canBv, bool& canTh, bool& canTv ) = 0;
  virtual bool canSplit                   ( const PartSplit split,                          const CodingStructure &cs ) = 0;
  virtual bool isSplitImplicit            ( const PartSplit split,                          const CodingStructure &cs ) = 0;
  virtual PartSplit getImplicitSplit      (                                                 const CodingStructure &cs ) = 0;
  bool isSepTree                          ( const CodingStructure &cs );
  bool isConsInter                        () { return modeType == MODE_TYPE_INTER; }
  bool isConsIntra                        () { return modeType == MODE_TYPE_INTRA; }
};

class AdaptiveDepthPartitioner : public Partitioner
{
public:
  void setMaxMinDepth( unsigned& minDepth, unsigned& maxDepth, const CodingStructure& cs ) const;
};

class QTBTPartitioner : public AdaptiveDepthPartitioner
{
public:
  void initCtu                    ( const UnitArea& ctuArea, const ChannelType _chType, const Slice& slice );
  void splitCurrArea              ( const PartSplit split, const CodingStructure &cs );
  void exitCurrSplit              ();
  bool nextPart                   ( const CodingStructure &cs, bool autoPop = false );
  bool hasNextPart                ();

  void canSplit                   ( const CodingStructure &cs, bool& canNo, bool& canQt, bool& canBh, bool& canBv, bool& canTh, bool& canTv );
  bool canSplit                   ( const PartSplit split,                          const CodingStructure &cs );
  bool isSplitImplicit            ( const PartSplit split,                          const CodingStructure &cs );
  PartSplit getImplicitSplit      (                                                 const CodingStructure &cs );
};

class TUIntraSubPartitioner : public Partitioner
{
public:
  TUIntraSubPartitioner(Partitioner& _initialState)
  {
    //we copy the input partitioner data
    m_partStack.push_back(PartLevel(TU_NO_ISP, { _initialState.currArea() }));

    currDepth    = _initialState.currDepth;
    currQtDepth  = _initialState.currQtDepth;
    currTrDepth  = _initialState.currTrDepth;
    currBtDepth  = _initialState.currBtDepth;
    currMtDepth  = _initialState.currMtDepth;
    chType       = _initialState.chType;
#if _DEBUG
    m_currArea   = _initialState.currArea();
#endif
    treeType     = _initialState.treeType;
    modeType     = _initialState.modeType;
  }

  void initCtu               (const UnitArea& ctuArea, const ChannelType chType, const Slice& slice) {}; // not needed
  void splitCurrArea         (const PartSplit split, const CodingStructure &cs);
  void exitCurrSplit         ();
  bool nextPart              (const CodingStructure &cs, bool autoPop = false);
  bool hasNextPart           ();
  void canSplit              (const CodingStructure &cs, bool& canNo, bool& canQt, bool& canBh, bool& canBv, bool& canTh, bool& canTv) {};
  bool canSplit              (const PartSplit split, const CodingStructure &cs);
  bool isSplitImplicit       (const PartSplit split, const CodingStructure &cs) { return false; }; //not needed
  PartSplit getImplicitSplit (const CodingStructure &cs) { return CU_DONT_SPLIT; }; //not needed
};

//////////////////////////////////////////////////////////////////////////
// Partitioner namespace - contains methods calculating the actual splits
//////////////////////////////////////////////////////////////////////////

namespace PartitionerImpl
{
  Partitioning getCUSubPartitions( const UnitArea   &cuArea, const CodingStructure &cs, const PartSplit splitType = CU_QUAD_SPLIT );
  Partitioning getMaxTuTiling    ( const UnitArea& curArea, const CodingStructure &cs );
  void    getTUIntraSubPartitions( Partitioning &sub, const UnitArea &tuArea, const CodingStructure &cs, const PartSplit splitType );
  Partitioning getSbtTuTiling    ( const UnitArea& curArea, const CodingStructure &cs, const PartSplit splitType );
};

#endif
