/*************************************************************************

    This project implements a complete(!) JPEG (Recommendation ITU-T
    T.81 | ISO/IEC 10918-1) codec, plus a library that can be used to
    encode and decode JPEG streams. 
    It also implements ISO/IEC 18477 aka JPEG XT which is an extension
    towards intermediate, high-dynamic-range lossy and lossless coding
    of JPEG. In specific, it supports ISO/IEC 18477-3/-6/-7/-8 encoding.

    Note that only Profiles C and D of ISO/IEC 18477-7 are supported
    here. Check the JPEG XT reference software for a full implementation
    of ISO/IEC 18477-7.

    Copyright (C) 2012-2018 Thomas Richter, University of Stuttgart and
    Accusoft. (C) 2019-2020 Thomas Richter, Fraunhofer IIS.

    This program is available under two licenses, GPLv3 and the ITU
    Software licence Annex A Option 2, RAND conditions.

    For the full text of the GPU license option, see README.license.gpl.
    For the full text of the ITU license option, see README.license.itu.
    
    You may freely select between these two options.

    For the GPL option, please note the following:

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.

*************************************************************************/
/*
 * The Art-Deco (MQ) decoder and encoder as specified by the jpeg2000 
 * standard, Recommendation ITU-T T.800 | ISO/IEC 15444-1.
 *
 * $Id: arthdeco.cpp,v 1.12 2018/07/27 06:56:43 thor Exp $
 *
 */

/// Includes
#include "io/bytestream.hpp"
#include "interface/types.hpp"
#include "coding/arthdeco.hpp"
#include "tools/checksum.hpp"
///

#if ACCUSOFT_CODE

/// MQCoder::Qe_Value
const UWORD MQCoder::Qe_Value[] = {
  0x5601,0x3401,0x1801,0x0ac1,0x0521,0x0221,0x5601,0x5401,0x4801,0x3801,
  0x3001,0x2401,0x1c01,0x1601,0x5601,0x54ff,0x5401,0x527d,0x5101,0x4c5f,
  0x4801,0x3f80,0x3801,0x35f7,0x3401,0x31f6,0x3001,0x2801,0x2401,0x2201,
  0x1c01,0x1801,0x1601,0x1401,0x1201,0x1101,0x0ac1,0x09c1,0x08a1,0x0521,
  0x0441,0x02a1,0x0221,0x0141,0x0111,0x0085,0x0049,0x0025,0x0015,0x0009,
  0x0005,0x0001,0x5601
};
///

/// MQCoder::Qe_Switch
const bool MQCoder::Qe_Switch[] = {
  1,0,0,0,0,0,1,0,0,0,
  0,0,0,0,1,0,0,0,0,0,
  0,0,0,0,0,0,0,0,0,0,
  0,0,0,0,0,0,0,0,0,0,
  0,0,0,0,0,0,0,0,0,0,
  0,0,0
};
///

/// MQCoder::Qe_NextMPS
const UBYTE MQCoder::Qe_NextMPS[] = {
  1,2,3,4,5,44,7,8,9,10,
  11,12,13,35,15,16,17,18,19,20,
  21,22,23,24,25,26,27,28,29,30,
  31,32,33,34,35,36,37,38,39,40,
  41,42,43,44,45,45,47,48,49,50,
  51,51,52
};
///

/// MQCoder::Qe_NextLPS
const UBYTE MQCoder::Qe_NextLPS[] = {
  1,6,9,12,35,39,6,14,14,14,
  20,22,25,27,14,14,14,15,16,17,
  18,19,20,21,22,23,24,25,26,27,
  28,29,30,31,32,33,34,35,36,37,
  38,39,40,41,42,43,44,45,46,47,
  48,49,52
};
///

/// MQCoder::InitContexts
// Initialize the contexts 
void MQCoder::InitContexts(void)
{
  int i;
  
  for(i = 0;i < Count;i++) {
    m_Contexts[i].m_ucIndex = 0;     // Simply start at context zero.
    m_Contexts[i].m_bMPS    = false; // MPS is zero.
  }
}
///

/// MQCoder::OpenForWrite
// Initialize the MQ Coder for writing to the
// indicated bytestream.
void MQCoder::OpenForWrite(class ByteStream *io,class Checksum *chk)
{
  m_ulA   = 0x8000;
  m_ulC   = 0x0000;
  m_ucCT  = 12;
  m_ucB   = 0x00;
  m_bF    = false;
  m_pIO   = io;
  m_pChk  = chk;
  InitContexts();
}
///

/// MQCoder::OpenForRead
// Initialize the MQ Coder for reading the indicated
// bytestream.
void MQCoder::OpenForRead(class ByteStream *io,class Checksum *chk)
{
  UBYTE t;
  
  m_pIO   = io;
  m_pChk  = chk;
  InitContexts();
  
  m_ucB   = io->Get();
  if (m_pChk)
    m_pChk->Update(m_ucB);
  m_ulC   = m_ucB << 16;
  t       = io->Get();
  if (m_pChk)
    m_pChk->Update(t);
  m_ucCT  = 8;
  
  if (m_ucB == 0xff) {
    if (t < 0x90) {
      m_ulC += t << 8;
      m_ucCT--;
    }
  }
  
  m_ulC  += t << 8;
  m_ucB   = t;
  m_ulC <<= 7;
  m_ucCT -= 7;
  m_ulA   = 0x8000;
}
///

/// MQCoder::Get
// Read a single bit from the MQCoder
// in a given context index.
bool MQCoder::Get(UBYTE ctxtidx)
{ 
  struct MQContext &ctxt = m_Contexts[ctxtidx];
  ULONG q = Qe_Value[ctxt.m_ucIndex];
  UBYTE t;
  bool d;

  assert(ctxtidx < Count);

  m_ulA -= q;
  if ((m_ulC >> 16) >= q) {
    // MPS case
    m_ulC -= q << 16;
    if (m_ulA & 0x8000) {
      // short MPS case.
      return ctxt.m_bMPS?true:false;
    }
    // MPS exchange case
    d = m_ulA < q; // true on LPS
  } else {
    // LPS exchange case
    d = m_ulA >= q; // true on LPS
    m_ulA = q;
  }

  if (d) {
    // LPS decoding, check for MPS/LPS exhchange.
    d ^= ctxt.m_bMPS;
    if (Qe_Switch[ctxt.m_ucIndex])
      ctxt.m_bMPS = d;
    ctxt.m_ucIndex = Qe_NextLPS[ctxt.m_ucIndex];
  } else {
    // MPS decoding
    d = ctxt.m_bMPS;
    ctxt.m_ucIndex = Qe_NextMPS[ctxt.m_ucIndex];
  }

  // 
  // Renormalize.
  do {
    if (m_ucCT == 0) {
      t = m_pIO->Get();
      if (m_pChk)
        m_pChk->Update(t);
      m_ucCT = 8;
      if (m_ucB == 0xff) {
        if (t < 0x90) {
          m_ulC += t << 8;
          m_ucCT--;
        }
      }
      m_ulC += t << 8;
      m_ucB  = t;
    }
    m_ulA  <<= 1;
    m_ulC  <<= 1;
    m_ucCT--;
  } while((m_ulA & 0x8000) == 0);

  return d;
}
///

/// MQCoder::Put
// Write a single bit to the stream.
void MQCoder::Put(UBYTE ctxtidx,bool bit)
{ 
  assert(ctxtidx < Count);
  
  struct MQContext &ctxt = m_Contexts[ctxtidx];
  ULONG q = Qe_Value[ctxt.m_ucIndex];

  m_ulA  -= q;
  // Check for MPS and LPS coding
  if (bit == ctxt.m_bMPS) {
    // MPS coding
    if (m_ulA & 0x8000) {
      // Short MPS case.
      m_ulC += q;
      return;
    } else {
      // Context change.
      if (m_ulA < q) {
        // MPS/LPS exchange.
        m_ulA  = q;
      } else {
        m_ulC += q;
      }
      ctxt.m_ucIndex = Qe_NextMPS[ctxt.m_ucIndex];
    }
  } else {
    // LPS coding here.
    if (m_ulA < q) {
      m_ulC += q;
    } else {
      m_ulA  = q;
    }
    //
    // MPS/LPS switch?
    ctxt.m_bMPS   ^= Qe_Switch[ctxt.m_ucIndex];
    ctxt.m_ucIndex = Qe_NextLPS[ctxt.m_ucIndex];
  }

  //
  // Renormalize
  do {
    m_ulA <<= 1;
    m_ulC <<= 1;
    if (--m_ucCT == 0) {
      if (m_ucB < 0xff) {
        if (m_ulC & 0x8000000) {
          // Overflow into the b register, remove carry.
          m_ucB++;
          m_ulC &= 0x7ffffff;
        }
      }
      if (m_ucB == 0xff) {
        // We either have an 0xff here, or generated one due to carry.
        // in either case, must have buffered something or the overflow
        // could not have happened.
        m_pIO->Put(0xff);
        if (m_pChk)
          m_pChk->Update(0xff);
        m_ucB  = m_ulC >> 20;
        m_ulC &= 0xfffff;
        m_ucCT = 7;
      } else {
        if (m_bF) {
          m_pIO->Put(m_ucB);
          if (m_pChk)
            m_pChk->Update(m_ucB);
        }
        m_ucB  = m_ulC >> 19;
        m_ulC &= 0x7ffff;
        m_ucCT = 8;
      }
      m_bF = true;
    }
  } while((m_ulA & 0x8000) == 0);
}
///

/// MQCoder::Flush
// Flush all remaining bits
void MQCoder::Flush(void)
{ 
  int k;
  //
  // Number of bits to push out is then in k.
  //
  m_ulC <<= m_ucCT;
  for(k = 12 - m_ucCT;k > 0;k -= m_ucCT,m_ulC <<= m_ucCT) {
    if (m_ucB < 0xff) {
      if (m_ulC & 0x8000000) {
        m_ucB++;
        m_ulC &= 0x7ffffff;
      }
    }
    if (m_ucB == 0xff) {
      m_pIO->Put(0xff);
      if (m_pChk)
        m_pChk->Update(0xff);
      m_ucB  = m_ulC >> 20;
      m_ulC &= 0xfffff;
      m_ucCT = 7;
    } else {
      if (m_bF) {
        m_pIO->Put(m_ucB);
        if (m_pChk)
          m_pChk->Update(m_ucB);
      }
      m_ucB  = m_ulC >> 19;
      m_ulC &= 0x7ffff;
      m_ucCT = 8;
    }
    m_bF = 1;
  }

  if (m_ucB < 0xff) {
    if (m_ulC & 0x8000000) {
      m_ucB++;
    }
  }
  if (m_ucB != 0xff && m_bF) {
    m_pIO->Put(m_ucB);
    if (m_pChk)
      m_pChk->Update(m_ucB);
  }
}
///

///
#endif