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/** \file     MotionInfo.h
    \brief    motion information handling classes (header)
    \todo     MvField seems to be better to be inherited from Mv
*/

#pragma once

#include "CommonDef.h"
#include "Mv.h"

namespace vvdec
{

// need miInvalid to be able to distinguish between different motion types, e.g. history, colocated or just motion info
static inline bool isMotionInvalid( int refIdx, const int miInvalid )
{
  static_assert( MH_NOT_VALID == -1 && MI_NOT_VALID == -1 && MF_NOT_VALID == -1 && CO_NOT_VALID == -1, "All not-valid motion need to be nagative for current impl!" );
  return refIdx < 0;
}

// need miInvalid to be able to distinguish between different motion types, e.g. history, colocated or just motion info
static inline bool isMotionValid( int refIdx, const int miInvalid )
{
  return !isMotionInvalid( refIdx, miInvalid );
}

// ====================================================================================================================
// Type definition
// ====================================================================================================================

/// parameters for AMVP
struct AMVPInfo
{
  Mv       mvCand[ AMVP_MAX_NUM_CANDS_MEM ];  ///< array of motion vector predictor candidates
  unsigned numCand;                       ///< number of motion vector predictor candidates
};

struct AffineAMVPInfo
{
  Mv       mvCandLT[ AMVP_MAX_NUM_CANDS_MEM ];  ///< array of affine motion vector predictor candidates for left-top corner
  Mv       mvCandRT[ AMVP_MAX_NUM_CANDS_MEM ];  ///< array of affine motion vector predictor candidates for right-top corner
  Mv       mvCandLB[ AMVP_MAX_NUM_CANDS_MEM ];  ///< array of affine motion vector predictor candidates for left-bottom corner
  unsigned numCand;                       ///< number of motion vector predictor candidates
};

// ====================================================================================================================
// Class definition
// ====================================================================================================================

/// class for motion vector with reference index
struct MvField
{
  Mv     mv;
  int8_t mfRefIdx = MF_NOT_VALID;

  MvField() = default;
  MvField( Mv const & cMv, const int iRefIdx ) : mv( cMv ), mfRefIdx(   iRefIdx ) {}

  void setMvField( Mv const & cMv, const int iRefIdx )
  {
    //CHECKD( iRefIdx == MF_NOT_VALID && cMv != Mv(0,0), "Must not happen." );
    mv     = cMv;
    mfRefIdx = iRefIdx;
  }

  bool operator==( const MvField& other ) const
  {
    //CHECKD( mfRefIdx == MF_NOT_VALID && mv != Mv(0,0), "Error in operator== of MvField." );
    //CHECKD( other.mfRefIdx == MF_NOT_VALID && other.mv != Mv(0,0), "Error in operator== of MvField." );
    return mfRefIdx == other.mfRefIdx && mv == other.mv;
  }
  bool operator!=( const MvField& other ) const
  {
    //CHECKD( mfRefIdx == MF_NOT_VALID && mv != Mv(0,0), "Error in operator!= of MvField." );
    //CHECKD( other.mfRefIdx == MF_NOT_VALID && other.mv != Mv(0,0), "Error in operator!= of MvField." );
    return mfRefIdx != other.mfRefIdx || mv != other.mv;
  }
};

struct MotionInfo
{
  Mv       mv      [NUM_REF_PIC_LIST_01];
  int8_t   miRefIdx[NUM_REF_PIC_LIST_01] = { MI_NOT_VALID, MI_NOT_VALID };

  bool operator==( const MotionInfo &mi ) const
  {
    if( miRefIdx[0] != mi.miRefIdx[0] ) return false;
    if( isMotionValid( miRefIdx[0], MI_NOT_VALID ) && mv[0] != mi.mv[0] ) return false;

    if( miRefIdx[1] != mi.miRefIdx[1] ) return false;
    if( isMotionValid( miRefIdx[1], MI_NOT_VALID ) && mv[1] != mi.mv[1] ) return false;

    return true;
  }

  bool operator!=( const MotionInfo &mi ) const
  {
    return !( *this == mi );
  }

  bool isInter() const
  {
    return interDir() != 0;
  }

  int interDir() const
  {
    int
    interDir  = isMotionInvalid( miRefIdx[0], MI_NOT_VALID ) ? 0 : 1;
    interDir += isMotionInvalid( miRefIdx[1], MI_NOT_VALID ) ? 0 : 2;
    return interDir;
  }
};

struct ColocatedMotionInfo
{
  Mv       mv      [NUM_REF_PIC_LIST_01];
  int8_t   coRefIdx[NUM_REF_PIC_LIST_01] = { CO_NOT_VALID, CO_NOT_VALID };

  int interDir() const
  {
    int
    interDir  = isMotionInvalid( coRefIdx[0], CO_NOT_VALID ) ? 0 : 1;
    interDir += isMotionInvalid( coRefIdx[1], CO_NOT_VALID ) ? 0 : 2;
    return interDir;
  }

  bool isInter() const
  {
    return interDir() != 0;
  }

  ColocatedMotionInfo &operator=( const MotionInfo &rhs )
  {
    static_assert( sizeof( MotionInfo ) == sizeof( ColocatedMotionInfo ), "MotionInfo and ColocatedMotionInfo require the same memory layout" );
    static_assert( std::is_standard_layout<MotionInfo>         ::value &&
                   std::is_standard_layout<ColocatedMotionInfo>::value,
                   "offsetof is only valid for standard layout types" );
    static_assert( offsetof( MotionInfo, mv )       == offsetof( ColocatedMotionInfo, mv ) &&
                   offsetof( MotionInfo, miRefIdx ) == offsetof( ColocatedMotionInfo, coRefIdx ),
                   "MotionInfo and ColocatedMotionInfo require the same memory layout" );

    memcpy( NO_WARNING_class_memaccess( this ), &rhs, sizeof( MotionInfo ) );

    return *this;
  }
};

struct HPMVInfo
{
  Mv       mv      [NUM_REF_PIC_LIST_01];
  int8_t   mhRefIdx[NUM_REF_PIC_LIST_01] = { MH_NOT_VALID, MH_NOT_VALID };

  uint8_t  BcwIdx       = 0;
  bool     useAltHpelIf = false;

  HPMVInfo() = default;
  HPMVInfo( const MotionInfo& mi, uint8_t BcwIdx, bool useAltHpelIf )
  {
    mv[0] = mi.mv[0];
    mv[1] = mi.mv[1];

    mhRefIdx[0] = mi.miRefIdx[0];
    mhRefIdx[1] = mi.miRefIdx[1];

    this->BcwIdx       = BcwIdx;
    this->useAltHpelIf = useAltHpelIf;
  }

  bool operator==( const HPMVInfo& mi ) const
  {
    if( mhRefIdx[0] != mi.mhRefIdx[0] ) return false;
    if( isMotionValid( mhRefIdx[0], MH_NOT_VALID ) && mv[0] != mi.mv[0] ) return false;

    if( mhRefIdx[1] != mi.mhRefIdx[1] ) return false;
    if( isMotionValid (mhRefIdx[1], MH_NOT_VALID ) && mv[1] != mi.mv[1] ) return false;

    return true;
  }

  bool operator!=( const HPMVInfo& mi ) const
  {
    return !( *this == mi );
  }

  int interDir() const
  {
    int
    interDir  = isMotionInvalid( mhRefIdx[0], MH_NOT_VALID ) ? 0 : 1;
    interDir += isMotionInvalid( mhRefIdx[1], MH_NOT_VALID ) ? 0 : 2;
    return interDir;
  }
};

struct MotionHist
{
  static_vector<HPMVInfo, MAX_NUM_HMVP_CANDS> motionLut;
  static_vector<HPMVInfo, MAX_NUM_HMVP_CANDS> motionLutIbc;
  
  static void addMiToLut( static_vector<HPMVInfo, MAX_NUM_HMVP_CANDS>& lut, const HPMVInfo &mi )
  {
    size_t currCnt = lut.size();

    bool pruned      = false;
    int  sameCandIdx = 0;

    for( int idx = 0; idx < currCnt; idx++ )
    {
      if( lut[idx] == mi )
      {
        sameCandIdx = idx;
        pruned = true;
        break;
      }
    }

    if( pruned || currCnt == lut.capacity() )
    {
      lut.erase( lut.begin() + sameCandIdx );
    }

    lut.push_back( mi );
  }
};

}
