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adpcm.cpp

/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * 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 2
 * 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, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * $URL: https://scummvm.svn.sourceforge.net/svnroot/scummvm/scummvm/tags/release-0-11-1/sound/adpcm.cpp $
 * $Id: adpcm.cpp 30944 2008-02-23 22:50:18Z sev $
 *
 */

#include "common/endian.h"

#include "sound/adpcm.h"
#include "sound/audiostream.h"


namespace Audio {

// TODO: Switch from a SeekableReadStream to a plain ReadStream. This requires
// some internal refactoring but is definitely possible and will increase the
// flexibility of this code.
class ADPCMInputStream : public AudioStream {
private:
      Common::SeekableReadStream *_stream;
      bool _disposeAfterUse;
      uint32 _endpos;
      int _channels;
      typesADPCM _type;
      uint32 _blockAlign;
      uint32 _blockPos;
      int _blockLen;
      int _rate;

      struct ADPCMChannelStatus {
            byte predictor;
            int16 delta;
            int16 coeff1;
            int16 coeff2;
            int16 sample1;
            int16 sample2;
      };

      struct adpcmStatus {
            // IMA
            int32 last;
            int32 stepIndex;

            // MS ADPCM
            ADPCMChannelStatus ch[2];
      } _status;

      int16 stepAdjust(byte);
      int16 decodeOKI(byte);
      int16 decodeMSIMA(byte);
      int16 decodeMS(ADPCMChannelStatus *c, byte);

public:
      ADPCMInputStream(Common::SeekableReadStream *stream, bool disposeAfterUse, uint32 size, typesADPCM type, int rate, int channels = 2, uint32 blockAlign = 0);
      ~ADPCMInputStream();

      int readBuffer(int16 *buffer, const int numSamples);
      int readBufferOKI(int16 *buffer, const int numSamples);
      int readBufferMSIMA1(int16 *buffer, const int numSamples);
      int readBufferMSIMA2(int16 *buffer, const int numSamples);
      int readBufferMS(int channels, int16 *buffer, const int numSamples);

      bool endOfData() const { return (_stream->eos() || _stream->pos() >= _endpos); }
      bool isStereo() const   { return false; }
      int getRate() const     { return _rate; }
};

// Routines to convert 12 bit linear samples to the
// Dialogic or Oki ADPCM coding format aka VOX.
// See also <http://www.comptek.ru/telephony/tnotes/tt1-13.html>
//
// In addition, also MS IMA ADPCM is supported. See
//   <http://wiki.multimedia.cx/index.php?title=Microsoft_IMA_ADPCM>.

ADPCMInputStream::ADPCMInputStream(Common::SeekableReadStream *stream, bool disposeAfterUse, uint32 size, typesADPCM type, int rate, int channels, uint32 blockAlign)
      : _stream(stream), _disposeAfterUse(disposeAfterUse), _channels(channels), _type(type), _blockAlign(blockAlign), _rate(rate) {

      _status.last = 0;
      _status.stepIndex = 0;
      memset(_status.ch, 0, sizeof(_status.ch));
      _endpos = stream->pos() + size;
      _blockLen = 0;
      _blockPos = _blockAlign; // To make sure first header is read

      if (type == kADPCMMSIma && blockAlign == 0)
            error("ADPCMInputStream(): blockAlign isn't specifiled for MS IMA ADPCM");
      if (type == kADPCMMS && blockAlign == 0)
            error("ADPCMInputStream(): blockAlign isn't specifiled for MS ADPCM");
}

ADPCMInputStream::~ADPCMInputStream() {
      if (_disposeAfterUse)
            delete _stream;
}

int ADPCMInputStream::readBuffer(int16 *buffer, const int numSamples) {
      switch (_type) {
      case kADPCMOki:
            return readBufferOKI(buffer, numSamples);
      case kADPCMMSIma:
            if (_channels == 1)
                  return readBufferMSIMA1(buffer, numSamples);
            else
                  return readBufferMSIMA2(buffer, numSamples);
      case kADPCMMS:
            return readBufferMS(_channels, buffer, numSamples);
      default:
            error("Unsupported ADPCM encoding");
            break;
      }
      return 0;
}

int ADPCMInputStream::readBufferOKI(int16 *buffer, const int numSamples) {
      int samples;
      byte data;

      assert(numSamples % 2 == 0);

      for (samples = 0; samples < numSamples && !_stream->eos() && _stream->pos() < _endpos; samples += 2) {
            data = _stream->readByte();
            buffer[samples] = TO_LE_16(decodeOKI((data >> 4) & 0x0f));
            buffer[samples + 1] = TO_LE_16(decodeOKI(data & 0x0f));
      }
      return samples;
}


int ADPCMInputStream::readBufferMSIMA1(int16 *buffer, const int numSamples) {
      int samples;
      byte data;

      assert(numSamples % 2 == 0);

      samples = 0;

      while (samples < numSamples && !_stream->eos() && _stream->pos() < _endpos) {
            if (_blockPos == _blockAlign) {
                  // read block header
                  _status.last = _stream->readSint16LE();
                  _status.stepIndex = _stream->readSint16LE();
                  _blockPos = 4;
            }

            for (; samples < numSamples && _blockPos < _blockAlign && !_stream->eos() && _stream->pos() < _endpos; samples += 2) {
                  data = _stream->readByte();
                  _blockPos++;
                  buffer[samples] = TO_LE_16(decodeMSIMA(data & 0x0f));
                  buffer[samples + 1] = TO_LE_16(decodeMSIMA((data >> 4) & 0x0f));
            }
      }
      return samples;
}


// Microsoft as usual tries to implement it differently. This method
// is used for stereo data.
int ADPCMInputStream::readBufferMSIMA2(int16 *buffer, const int numSamples) {
      int samples;
      uint32 data;
      int nibble;

      for (samples = 0; samples < numSamples && !_stream->eos() && _stream->pos() < _endpos;) {
            for (int channel = 0; channel < 2; channel++) {
                  data = _stream->readUint32LE();

                  for (nibble = 0; nibble < 8; nibble++) {
                        byte k = ((data & 0xf0000000) >> 28);
                        buffer[samples + channel + nibble * 2] = TO_LE_16(decodeMSIMA(k));
                        data <<= 4;
                  }
            }
            samples += 16;
      }
      return samples;
}

static const int MSADPCMAdaptCoeff1[] = {
      256, 512, 0, 192, 240, 460, 392
};

static const int MSADPCMAdaptCoeff2[] = {
      0, -256, 0, 64, 0, -208, -232
};

int ADPCMInputStream::readBufferMS(int channels, int16 *buffer, const int numSamples) {
      int samples;
      byte data;
      int stereo = channels - 1; // We use it in index

      samples = 0;

      while (samples < numSamples && !_stream->eos() && _stream->pos() < _endpos) {
            if (_blockPos == _blockAlign) {
                  // read block header
                  _status.ch[0].predictor = CLIP(_stream->readByte(), (byte)0, (byte)6);
                  _status.ch[0].coeff1 = MSADPCMAdaptCoeff1[_status.ch[0].predictor];
                  _status.ch[0].coeff2 = MSADPCMAdaptCoeff2[_status.ch[0].predictor];
                  if (stereo) {
                        _status.ch[1].predictor = CLIP(_stream->readByte(), (byte)0, (byte)6);
                        _status.ch[1].coeff1 = MSADPCMAdaptCoeff1[_status.ch[1].predictor];
                        _status.ch[1].coeff2 = MSADPCMAdaptCoeff2[_status.ch[1].predictor];
                  }

                  _status.ch[0].delta = _stream->readSint16LE();
                  if (stereo)
                        _status.ch[1].delta = _stream->readSint16LE();

                  _status.ch[0].sample1 = _stream->readSint16LE();
                  if (stereo)
                        _status.ch[1].sample1 = _stream->readSint16LE();

                  buffer[samples++] = _status.ch[0].sample2 = _stream->readSint16LE();

                  if (stereo)
                        buffer[samples++] = _status.ch[1].sample2 = _stream->readSint16LE();

                  buffer[samples++] = _status.ch[0].sample1;
                  if (stereo)
                        buffer[samples++] = _status.ch[1].sample1;

                  _blockPos = channels * 7;
            }

            for (; samples < numSamples && _blockPos < _blockAlign && !_stream->eos() && _stream->pos() < _endpos; samples += 2) {
                  data = _stream->readByte();
                  _blockPos++;
                  buffer[samples] = TO_LE_16(decodeMS(&_status.ch[0], (data >> 4) & 0x0f));
                  buffer[samples + 1] = TO_LE_16(decodeMS(&_status.ch[stereo], data & 0x0f));
            }
      }

      return samples;
}


static const int MSADPCMAdaptationTable[] = {
      230, 230, 230, 230, 307, 409, 512, 614,
      768, 614, 512, 409, 307, 230, 230, 230
};


int16 ADPCMInputStream::decodeMS(ADPCMChannelStatus *c, byte code) {
      int32 predictor;

      predictor = (((c->sample1) * (c->coeff1)) + ((c->sample2) * (c->coeff2))) / 256;
      predictor += (signed)((code & 0x08) ? (code - 0x10) : (code)) * c->delta;

      if (predictor < -32768)
            predictor = -32768;
      else if (predictor > 32767)
            predictor = 32767;

      c->sample2 = c->sample1;
      c->sample1 = predictor;
      c->delta = (MSADPCMAdaptationTable[(int)code] * c->delta) >> 8;

      if (c->delta < 16)
            c->delta = 16;

      return (int16)predictor;
}

// adjust the step for use on the next sample.
int16 ADPCMInputStream::stepAdjust(byte code) {
      static const int16 adjusts[] = {-1, -1, -1, -1, 2, 4, 6, 8};

      return adjusts[code & 0x07];
}

static const int16 okiStepSize[49] = {
        16,   17,   19,   21,   23,   25,   28,   31,
        34,   37,   41,   45,   50,   55,   60,   66,
        73,   80,   88,   97,  107,  118,  130,  143,
       157,  173,  190,  209,  230,  253,  279,  307,
       337,  371,  408,  449,  494,  544,  598,  658,
       724,  796,  876,  963, 1060, 1166, 1282, 1411,
      1552
};

// Decode Linear to ADPCM
int16 ADPCMInputStream::decodeOKI(byte code) {
      int16 diff, E, samp;

      E = (2 * (code & 0x7) + 1) * okiStepSize[_status.stepIndex] / 8;
      diff = (code & 0x08) ? -E : E;
      samp = _status.last + diff;

      // Clip the values to +/- 2^11 (supposed to be 12 bits)
      if (samp > 2047)
            samp = 2047;
      if (samp < -2048)
            samp = -2048;

      _status.last = samp;
      _status.stepIndex += stepAdjust(code);
      if (_status.stepIndex < 0)
            _status.stepIndex = 0;
      if (_status.stepIndex > ARRAYSIZE(okiStepSize) - 1)
            _status.stepIndex = ARRAYSIZE(okiStepSize) - 1;

      // * 16 effectively converts 12-bit input to 16-bit output
      return samp * 16;
}


static const uint16 imaStepTable[89] = {
            7,      8,  9,     10,   11,   12,   13,   14,
         16,       17,   19,   21,   23,   25,   28,   31,
         34,       37,   41,   45,   50,   55,   60,   66,
         73,       80,   88,   97,  107,  118,  130,  143,
        157,      173,  190,  209,  230,  253,  279,  307,
        337,      371,  408,  449,  494,  544,  598,  658,
        724,      796,  876,  963, 1060, 1166, 1282, 1411,
       1552, 1707, 1878, 2066, 2272, 2499, 2749, 3024,
       3327, 3660, 4026, 4428, 4871, 5358, 5894, 6484,
       7132, 7845, 8630, 9493,10442,11487,12635,13899,
      15289,16818,18500,20350,22385,24623,27086,29794,
      32767
};

int16 ADPCMInputStream::decodeMSIMA(byte code) {
      int32 diff, E, samp;

      E = (2 * (code & 0x7) + 1) * imaStepTable[_status.stepIndex] / 8;
      diff = (code & 0x08) ? -E : E;
      samp = _status.last + diff;

      if (samp < -32768)
            samp = -32768;
      else if (samp > 32767)
            samp = 32767;

      _status.last = samp;
      _status.stepIndex += stepAdjust(code);
      if (_status.stepIndex < 0)
            _status.stepIndex = 0;
      if (_status.stepIndex > ARRAYSIZE(imaStepTable) - 1)
            _status.stepIndex = ARRAYSIZE(imaStepTable) - 1;

      return samp;
}

AudioStream *makeADPCMStream(Common::SeekableReadStream *stream, bool disposeAfterUse, uint32 size, typesADPCM type, int rate, int channels, uint32 blockAlign) {
      return new ADPCMInputStream(stream, disposeAfterUse, size, type, rate, channels, blockAlign);
}

} // End of namespace Audio

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