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

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) 2019-2026, Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. & The VVenC 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

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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

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

#include "BinEncoder.h"

#include "CommonLib/Rom.h"

#include "CommonLib/dtrace_next.h"

//! \ingroup EncoderLib

//! \{

namespace vvenc {

BinCounter::BinCounter()

  : m_CtxBinsCodedBuffer( Ctx::NumberOfContexts )

  , m_NumBinsCtx        ( m_CtxBinsCodedBuffer.data() )

  , m_NumBinsEP         ( 0 )

  , m_NumBinsTrm        ( 0 )

{}

void BinCounter::reset()

{

  for( std::size_t k = 0; k < m_CtxBinsCodedBuffer.size(); k++ )

  {

    m_NumBinsCtx[k] = 0;

  }

  m_NumBinsEP       = 0;

  m_NumBinsTrm      = 0;

}

uint32_t BinCounter::getAll() const

{

  uint32_t  count = m_NumBinsEP + m_NumBinsTrm;

  for( std::size_t k = 0; k < m_CtxBinsCodedBuffer.size(); k++ )

  {

    count += m_NumBinsCtx[k];

  }

  return count;

}

BinEncoderBase::BinEncoderBase( const BinProbModel* dummy )

  : BinEncIf          ( dummy )

  , m_Bitstream       ( 0 )

  , m_Low             ( 0 )

  , m_Range           ( 0 )

  , m_bufferedByte    ( 0 )

  , m_numBufferedBytes( 0 )

  , m_bitsLeft        ( 0 )

{}

void BinEncoderBase::init( OutputBitstream* bitstream )

{

  m_Bitstream = bitstream;

}

void BinEncoderBase::uninit()

{

  m_Bitstream = 0;

}

void BinEncoderBase::start()

{

  m_Low               = 0;

  m_Range             = 510;

  m_bufferedByte      = 0xff;

  m_numBufferedBytes  = 0;

  m_bitsLeft          = 23;

  BinCounter::reset();

  m_BinStore. reset();

}

void BinEncoderBase::finish()

{

  if( m_Low >> ( 32 - m_bitsLeft ) )

  {

    m_Bitstream->write( m_bufferedByte + 1, 8 );

    while( m_numBufferedBytes > 1 )

    {

      m_Bitstream->write( 0x00, 8 );

      m_numBufferedBytes--;

    }

    m_Low -= 1 << ( 32 - m_bitsLeft );

  }

  else

  {

    if( m_numBufferedBytes > 0 )

    {

      m_Bitstream->write( m_bufferedByte, 8 );

    }

    while( m_numBufferedBytes > 1 )

    {

      m_Bitstream->write( 0xff, 8 );

      m_numBufferedBytes--;

    }

  }

  m_Bitstream->write( m_Low >> 8, 24 - m_bitsLeft );

}

void BinEncoderBase::restart()

{

  m_Low               = 0;

  m_Range             = 510;

  m_bufferedByte      = 0xff;

  m_numBufferedBytes  = 0;

  m_bitsLeft          = 23;

}

void BinEncoderBase::reset( int qp, int initId )

{

  Ctx::init( qp, initId );

  start();

}

void BinEncoderBase::resetBits()

{

  m_Low               = 0;

  m_bufferedByte      = 0xff;

  m_numBufferedBytes  = 0;

  m_bitsLeft          = 23;

  BinCounter::reset();

}

void BinEncoderBase::encodeBinEP( unsigned bin )

{

  DTRACE( g_trace_ctx, D_CABAC, "%d" "  " "%d" "  EP=%d \n", DTRACE_GET_COUNTER( g_trace_ctx, D_CABAC ), m_Range, bin );

  BinCounter::addEP();

  m_Low <<= 1;

  if( bin )

  {

    m_Low += m_Range;

  }

  m_bitsLeft--;

  if( m_bitsLeft < 12 )

  {

    writeOut();

  }

}

void BinEncoderBase::encodeBinsEP( unsigned bins, unsigned numBins )

{

  for(int i = 0; i < numBins; i++)

  {

    DTRACE( g_trace_ctx, D_CABAC, "%d" "  " "%d" "  EP=%d \n", DTRACE_GET_COUNTER( g_trace_ctx, D_CABAC ), m_Range, ( bins >> ( numBins - 1 - i ) ) & 1 );

  }

  BinCounter::addEP( numBins );

  if( m_Range == 256 )

  {

    encodeAlignedBinsEP( bins, numBins );

    return;

  }

  while( numBins > 8 )

  {

    numBins          -= 8;

    unsigned pattern  = bins >> numBins;

    m_Low           <<= 8;

    m_Low            += m_Range * pattern;

    bins             -= pattern << numBins;

    m_bitsLeft       -= 8;

    if( m_bitsLeft < 12 )

    {

      writeOut();

    }

  }

  m_Low     <<= numBins;

  m_Low      += m_Range * bins;

  m_bitsLeft -= numBins;

  if( m_bitsLeft < 12 )

  {

    writeOut();

  }

}

void BinEncoderBase::encodeRemAbsEP(unsigned bins, unsigned goRicePar, unsigned cutoff, int maxLog2TrDynamicRange)

{

  const unsigned threshold = cutoff << goRicePar;

  if (bins < threshold)

  {

    const unsigned bitMask = (1 << goRicePar) - 1;

    const unsigned length = (bins >> goRicePar) + 1;

    encodeBinsEP((1 << length) - 2, length);

    encodeBinsEP(bins & bitMask, goRicePar);

  }

  else 

  {

    const unsigned  maxPrefixLength = 32 - cutoff - maxLog2TrDynamicRange;

    unsigned        prefixLength = 0;

    unsigned        codeValue = (bins >> goRicePar) - cutoff;

    unsigned        suffixLength;

    if (codeValue >= ((1 << maxPrefixLength) - 1))

    {

      prefixLength = maxPrefixLength;

      suffixLength = maxLog2TrDynamicRange;

    }

    else

    {

      while (codeValue > ((2 << prefixLength) - 2))

      {

        prefixLength++;

      }

      suffixLength = prefixLength + goRicePar + 1; //+1 for the separator bit

    }

    const unsigned totalPrefixLength = prefixLength + cutoff;

    const unsigned bitMask = (1 << goRicePar) - 1;

    const unsigned prefix = (1 << totalPrefixLength) - 1;

    const unsigned suffix = ((codeValue - ((1 << prefixLength) - 1)) << goRicePar) | (bins & bitMask);

    encodeBinsEP(prefix, totalPrefixLength); //prefix

    encodeBinsEP(suffix, suffixLength); //separator, suffix, and rParam bits

  }

}

void BinEncoderBase::encodeBinTrm( unsigned bin )

{

  BinCounter::addTrm();

  m_Range -= 2;

  if( bin )

  {

    m_Low      += m_Range;

    m_Low     <<= 7;

    m_Range     = 2 << 7;

    m_bitsLeft -= 7;

  }

  else if( m_Range >= 256 )

  {

    return;

  }

  else

  {

    m_Low     <<= 1;

    m_Range   <<= 1;

    m_bitsLeft--;

  }

  if( m_bitsLeft < 12 )

  {

    writeOut();

  }

}

void BinEncoderBase::align()

{

  m_Range = 256;

}

void BinEncoderBase::encodeAlignedBinsEP( unsigned bins, unsigned numBins )

{

  unsigned remBins = numBins;

  while( remBins > 0 )

  {

    //The process of encoding an EP bin is the same as that of coding a normal

    //bin where the symbol ranges for 1 and 0 are both half the range:

    //

    //  low = (low + range/2) << 1       (to encode a 1)

    //  low =  low            << 1       (to encode a 0)

    //

    //  i.e.

    //  low = (low + (bin * range/2)) << 1

    //

    //  which is equivalent to:

    //

    //  low = (low << 1) + (bin * range)

    //

    //  this can be generalised for multiple bins, producing the following expression:

    //

    unsigned binsToCode = std::min<unsigned>( remBins, 8); //code bytes if able to take advantage of the system's byte-write function

    unsigned binMask    = ( 1 << binsToCode ) - 1;

    unsigned newBins    = ( bins >> ( remBins - binsToCode ) ) & binMask;

    m_Low               = ( m_Low << binsToCode ) + ( newBins << 8 ); //range is known to be 256

    remBins            -= binsToCode;

    m_bitsLeft         -= binsToCode;

    if( m_bitsLeft < 12 )

    {

      writeOut();

    }

  }

}

void BinEncoderBase::writeOut()

{

  unsigned leadByte = m_Low >> ( 24 - m_bitsLeft );

  m_bitsLeft       += 8;

  m_Low            &= 0xffffffffu >> m_bitsLeft;

  if( leadByte == 0xff )

  {

    m_numBufferedBytes++;

  }

  else

  {

    if( m_numBufferedBytes > 0 )

    {

      unsigned carry  = leadByte >> 8;

      unsigned byte   = m_bufferedByte + carry;

      m_bufferedByte  = leadByte & 0xff;

      m_Bitstream->write( byte, 8 );

      byte            = ( 0xff + carry ) & 0xff;

      while( m_numBufferedBytes > 1 )

      {

        m_Bitstream->write( byte, 8 );

        m_numBufferedBytes--;

      }

    }

    else

    {

      m_numBufferedBytes  = 1;

      m_bufferedByte      = leadByte;

    }

  }

}

BinEncoder::BinEncoder()

  : BinEncoderBase( static_cast<const BinProbModel*>    ( nullptr ) )

  , m_Ctx         ( static_cast<CtxStore&>( *this   ) )

{}

void BinEncoder::encodeBin( unsigned bin, unsigned ctxId )

{

  BinCounter::addCtx( ctxId );

  BinProbModel& rcProbModel = m_Ctx[ctxId];

  uint32_t      LPS         = rcProbModel.getLPS( m_Range );

//  DTRACE( g_trace_ctx, D_CABAC, "%d" " %d " "%d" "  " "[%d:%d]" "  " "%2d(MPS=%d)"  "  " "  -  " "%d" "\n", DTRACE_GET_COUNTER( g_trace_ctx, D_CABAC ), ctxId, m_Range, m_Range - LPS, LPS, ( unsigned int ) ( rcProbModel.state() ), bin == rcProbModel.mps(), bin );

  DTRACE( g_trace_ctx, D_CABAC, " %d " "%d" "  " "[%d:%d]" "  " "%2d(MPS=%d)"  "  " "  -  " "%d" "\n", DTRACE_GET_COUNTER( g_trace_ctx, D_CABAC ), m_Range, m_Range - LPS, LPS, (unsigned int)( rcProbModel.state() ), bin == rcProbModel.mps(), bin );

  m_Range   -=  LPS;

  if( bin != rcProbModel.mps() )

  {

    int numBits   = rcProbModel.getRenormBitsLPS( LPS );

    m_bitsLeft   -= numBits;

    m_Low        += m_Range;

    m_Low         = m_Low << numBits;

    m_Range       = LPS   << numBits;

    if( m_bitsLeft < 12 )

    {

      writeOut();

    }

  }

  else

  {

    if( m_Range < 256 )

    {

      //int numBits   = rcProbModel.getRenormBitsRange();

      int numBits   = 1;

      m_bitsLeft   -= numBits;

      m_Low       <<= numBits;

      m_Range     <<= numBits;

      if( m_bitsLeft < 12 )

      {

        writeOut();

      }

    }

  }

  rcProbModel.update( bin );

  BinEncoderBase::m_BinStore.addBin( bin, ctxId );

}

BinEncIf* BinEncoder::getTestBinEncoder() const

{

  BinEncIf* testBinEncoder = 0;

  if( m_BinStore.inUse() )

  {

    testBinEncoder = new BinEncoder();

  }

  return testBinEncoder;

}

BitEstimatorBase::BitEstimatorBase( const BinProbModel* dummy )

  : BinEncIf      ( dummy )

{

  m_EstFracBits = 0;

}

void BitEstimatorBase::encodeRemAbsEP(unsigned bins, unsigned goRicePar, unsigned cutoff, int maxLog2TrDynamicRange)

{

  m_EstFracBits += BinProbModelBase::estFracBitsEP( numRemAbsEPBins( bins, goRicePar, cutoff, maxLog2TrDynamicRange ) );

}

unsigned BitEstimatorBase::numRemAbsEPBins( unsigned bins, unsigned goRicePar, unsigned cutoff, int maxLog2TrDynamicRange )

{

  const unsigned threshold = cutoff << goRicePar;

  if (bins < threshold)

  {

    return (bins >> goRicePar) + 1 + goRicePar;

  }

  else 

  {

    const unsigned  maxPrefixLength = 32 - cutoff - maxLog2TrDynamicRange;

    unsigned        prefixLength = 0;

    unsigned        codeValue = (bins >> goRicePar) - cutoff;

    unsigned        suffixLength;

    if (codeValue >= ((1 << maxPrefixLength) - 1))

    {

      prefixLength = maxPrefixLength;

      suffixLength = maxLog2TrDynamicRange;

    }

    else

    {

      while (codeValue > ((2 << prefixLength) - 2))

      {

        prefixLength++;

      }

      suffixLength = prefixLength + goRicePar + 1; //+1 for the separator bit

    }

    return cutoff + prefixLength + suffixLength;

  }

}

void BitEstimatorBase::align()

{

  static const uint64_t add   = BinProbModelBase::estFracBitsEP() - 1;

  static const uint64_t mask  = ~add;

  m_EstFracBits += add;

  m_EstFracBits &= mask;

}

BitEstimator::BitEstimator()

  : BitEstimatorBase  ( static_cast<const BinProbModel*>    ( nullptr) )

  , m_Ctx             ( static_cast<CtxStore&>              ( *this  ) )

{}

} // namespace vvenc

//! \}