lzma.js

var LZMA = LZMA || {};

LZMA.OutWindow = function(){
  this._windowSize = 0;
};

LZMA.OutWindow.prototype.create = function(windowSize){
  if ( (!this._buffer) || (this._windowSize !== windowSize) ){
    this._buffer = [];
  }
  this._windowSize = windowSize;
  this._pos = 0;
  this._streamPos = 0;
};

LZMA.OutWindow.prototype.flush = function(){
  var size = this._pos - this._streamPos;
  if (size !== 0){
    while(size --){
      this._stream.writeByte(this._buffer[this._streamPos ++]);
    }
    if (this._pos >= this._windowSize){
      this._pos = 0;
    }
    this._streamPos = this._pos;
  }
};

LZMA.OutWindow.prototype.releaseStream = function(){
  this.flush();
  this._stream = null;
};

LZMA.OutWindow.prototype.setStream = function(stream){
  this.releaseStream();
  this._stream = stream;
};

LZMA.OutWindow.prototype.init = function(solid){
  if (!solid){
    this._streamPos = 0;
    this._pos = 0;
  }
};

LZMA.OutWindow.prototype.copyBlock = function(distance, len){
  var pos = this._pos - distance - 1;
  if (pos < 0){
    pos += this._windowSize;
  }
  while(len --){
    if (pos >= this._windowSize){
      pos = 0;
    }
    this._buffer[this._pos ++] = this._buffer[pos ++];
    if (this._pos >= this._windowSize){
      this.flush();
    }
  }
};

LZMA.OutWindow.prototype.putByte = function(b){
  this._buffer[this._pos ++] = b;
  if (this._pos >= this._windowSize){
    this.flush();
  }
};

LZMA.OutWindow.prototype.getByte = function(distance){
  var pos = this._pos - distance - 1;
  if (pos < 0){
    pos += this._windowSize;
  }
  return this._buffer[pos];
};

LZMA.RangeDecoder = function(){
};

LZMA.RangeDecoder.prototype.setStream = function(stream){
  this._stream = stream;
};

LZMA.RangeDecoder.prototype.releaseStream = function(){
  this._stream = null;
};

LZMA.RangeDecoder.prototype.init = function(){
  var i = 5;

  this._code = 0;
  this._range = -1;
  
  while(i --){
    this._code = (this._code << 8) | this._stream.readByte();
  }
};

LZMA.RangeDecoder.prototype.decodeDirectBits = function(numTotalBits){
  var result = 0, i = numTotalBits, t;

  while(i --){
    this._range >>>= 1;
    t = (this._code - this._range) >>> 31;
    this._code -= this._range & (t - 1);
    result = (result << 1) | (1 - t);

    if ( (this._range & 0xff000000) === 0){
      this._code = (this._code << 8) | this._stream.readByte();
      this._range <<= 8;
    }
  }

  return result;
};

LZMA.RangeDecoder.prototype.decodeBit = function(probs, index){
  var prob = probs[index],
      newBound = (this._range >>> 11) * prob;

  if ( (this._code ^ 0x80000000) < (newBound ^ 0x80000000) ){
    this._range = newBound;
    probs[index] += (2048 - prob) >>> 5;
    if ( (this._range & 0xff000000) === 0){
      this._code = (this._code << 8) | this._stream.readByte();
      this._range <<= 8;
    }
    return 0;
  }

  this._range -= newBound;
  this._code -= newBound;
  probs[index] -= prob >>> 5;
  if ( (this._range & 0xff000000) === 0){
    this._code = (this._code << 8) | this._stream.readByte();
    this._range <<= 8;
  }
  return 1;
};

LZMA.initBitModels = function(probs, len){
  while(len --){
    probs[len] = 1024;
  }
};

LZMA.BitTreeDecoder = function(numBitLevels){
  this._models = [];
  this._numBitLevels = numBitLevels;
};

LZMA.BitTreeDecoder.prototype.init = function(){
  LZMA.initBitModels(this._models, 1 << this._numBitLevels);
};

LZMA.BitTreeDecoder.prototype.decode = function(rangeDecoder){
  var m = 1, i = this._numBitLevels;

  while(i --){
    m = (m << 1) | rangeDecoder.decodeBit(this._models, m);
  }
  return m - (1 << this._numBitLevels);
};

LZMA.BitTreeDecoder.prototype.reverseDecode = function(rangeDecoder){
  var m = 1, symbol = 0, i = 0, bit;

  for (; i < this._numBitLevels; ++ i){
    bit = rangeDecoder.decodeBit(this._models, m);
    m = (m << 1) | bit;
    symbol |= bit << i;
  }
  return symbol;
};

LZMA.reverseDecode2 = function(models, startIndex, rangeDecoder, numBitLevels){
  var m = 1, symbol = 0, i = 0, bit;

  for (; i < numBitLevels; ++ i){
    bit = rangeDecoder.decodeBit(models, startIndex + m);
    m = (m << 1) | bit;
    symbol |= bit << i;
  }
  return symbol;
};

LZMA.LenDecoder = function(){
  this._choice = [];
  this._lowCoder = [];
  this._midCoder = [];
  this._highCoder = new LZMA.BitTreeDecoder(8);
  this._numPosStates = 0;
};

LZMA.LenDecoder.prototype.create = function(numPosStates){
  for (; this._numPosStates < numPosStates; ++ this._numPosStates){
    this._lowCoder[this._numPosStates] = new LZMA.BitTreeDecoder(3);
    this._midCoder[this._numPosStates] = new LZMA.BitTreeDecoder(3);
  }
};

LZMA.LenDecoder.prototype.init = function(){
  var i = this._numPosStates;
  LZMA.initBitModels(this._choice, 2);
  while(i --){
    this._lowCoder[i].init();
    this._midCoder[i].init();
  }
  this._highCoder.init();
};

LZMA.LenDecoder.prototype.decode = function(rangeDecoder, posState){
  if (rangeDecoder.decodeBit(this._choice, 0) === 0){
    return this._lowCoder[posState].decode(rangeDecoder);
  }
  if (rangeDecoder.decodeBit(this._choice, 1) === 0){
    return 8 + this._midCoder[posState].decode(rangeDecoder);
  }
  return 16 + this._highCoder.decode(rangeDecoder);
};

LZMA.Decoder2 = function(){
  this._decoders = [];
};

LZMA.Decoder2.prototype.init = function(){
  LZMA.initBitModels(this._decoders, 0x300);
};

LZMA.Decoder2.prototype.decodeNormal = function(rangeDecoder){
  var symbol = 1;

  do{
    symbol = (symbol << 1) | rangeDecoder.decodeBit(this._decoders, symbol);
  }while(symbol < 0x100);

  return symbol & 0xff;
};

LZMA.Decoder2.prototype.decodeWithMatchByte = function(rangeDecoder, matchByte){
  var symbol = 1, matchBit, bit;

  do{
    matchBit = (matchByte >> 7) & 1;
    matchByte <<= 1;
    bit = rangeDecoder.decodeBit(this._decoders, ( (1 + matchBit) << 8) + symbol);
    symbol = (symbol << 1) | bit;
    if (matchBit !== bit){
      while(symbol < 0x100){
        symbol = (symbol << 1) | rangeDecoder.decodeBit(this._decoders, symbol);
      }
      break;
    }
  }while(symbol < 0x100);

  return symbol & 0xff;
};

LZMA.LiteralDecoder = function(){
};

LZMA.LiteralDecoder.prototype.create = function(numPosBits, numPrevBits){
  var i;

  if (this._coders
    && (this._numPrevBits === numPrevBits)
    && (this._numPosBits === numPosBits) ){
    return;
  }
  this._numPosBits = numPosBits;
  this._posMask = (1 << numPosBits) - 1;
  this._numPrevBits = numPrevBits;

  this._coders = [];

  i = 1 << (this._numPrevBits + this._numPosBits);
  while(i --){
    this._coders[i] = new LZMA.Decoder2();
  }
};

LZMA.LiteralDecoder.prototype.init = function(){
  var i = 1 << (this._numPrevBits + this._numPosBits);
  while(i --){
    this._coders[i].init();
  }
};

LZMA.LiteralDecoder.prototype.getDecoder = function(pos, prevByte){
  return this._coders[( (pos & this._posMask) << this._numPrevBits)
    + ( (prevByte & 0xff) >>> (8 - this._numPrevBits) )];
};

LZMA.Decoder = function(){
  this._outWindow = new LZMA.OutWindow();
  this._rangeDecoder = new LZMA.RangeDecoder();
  this._isMatchDecoders = [];
  this._isRepDecoders = [];
  this._isRepG0Decoders = [];
  this._isRepG1Decoders = [];
  this._isRepG2Decoders = [];
  this._isRep0LongDecoders = [];
  this._posSlotDecoder = [];
  this._posDecoders = [];
  this._posAlignDecoder = new LZMA.BitTreeDecoder(4);
  this._lenDecoder = new LZMA.LenDecoder();
  this._repLenDecoder = new LZMA.LenDecoder();
  this._literalDecoder = new LZMA.LiteralDecoder();
  this._dictionarySize = -1;
  this._dictionarySizeCheck = -1;

  this._posSlotDecoder[0] = new LZMA.BitTreeDecoder(6);
  this._posSlotDecoder[1] = new LZMA.BitTreeDecoder(6);
  this._posSlotDecoder[2] = new LZMA.BitTreeDecoder(6);
  this._posSlotDecoder[3] = new LZMA.BitTreeDecoder(6);
};

LZMA.Decoder.prototype.setDictionarySize = function(dictionarySize){
  if (dictionarySize < 0){
    return false;
  }
  if (this._dictionarySize !== dictionarySize){
    this._dictionarySize = dictionarySize;
    this._dictionarySizeCheck = Math.max(this._dictionarySize, 1);
    this._outWindow.create( Math.max(this._dictionarySizeCheck, 4096) );
  }
  return true;
};

LZMA.Decoder.prototype.setLcLpPb = function(lc, lp, pb){
  var numPosStates = 1 << pb;

  if (lc > 8 || lp > 4 || pb > 4){
    return false;
  }

  this._literalDecoder.create(lp, lc);

  this._lenDecoder.create(numPosStates);
  this._repLenDecoder.create(numPosStates);
  this._posStateMask = numPosStates - 1;

  return true;
};

LZMA.Decoder.prototype.init = function(){
  var i = 4;

  this._outWindow.init(false);

  LZMA.initBitModels(this._isMatchDecoders, 192);
  LZMA.initBitModels(this._isRep0LongDecoders, 192);
  LZMA.initBitModels(this._isRepDecoders, 12);
  LZMA.initBitModels(this._isRepG0Decoders, 12);
  LZMA.initBitModels(this._isRepG1Decoders, 12);
  LZMA.initBitModels(this._isRepG2Decoders, 12);
  LZMA.initBitModels(this._posDecoders, 114);

  this._literalDecoder.init();

  while(i --){
    this._posSlotDecoder[i].init();
  }

  this._lenDecoder.init();
  this._repLenDecoder.init();
  this._posAlignDecoder.init();
  this._rangeDecoder.init();
};

LZMA.Decoder.prototype.decode = function(inStream, outStream, outSize){
  var state = 0, rep0 = 0, rep1 = 0, rep2 = 0, rep3 = 0, nowPos64 = 0, prevByte = 0,
      posState, decoder2, len, distance, posSlot, numDirectBits;

  this._rangeDecoder.setStream(inStream);
  this._outWindow.setStream(outStream);

  this.init();

  while(outSize < 0 || nowPos64 < outSize){
    posState = nowPos64 & this._posStateMask;

    if (this._rangeDecoder.decodeBit(this._isMatchDecoders, (state << 4) + posState) === 0){
      decoder2 = this._literalDecoder.getDecoder(nowPos64 ++, prevByte);

      if (state >= 7){
        prevByte = decoder2.decodeWithMatchByte(this._rangeDecoder, this._outWindow.getByte(rep0) );
      }else{
        prevByte = decoder2.decodeNormal(this._rangeDecoder);
      }
      this._outWindow.putByte(prevByte);

      state = state < 4? 0: state - (state < 10? 3: 6);

    }else{

      if (this._rangeDecoder.decodeBit(this._isRepDecoders, state) === 1){
        len = 0;
        if (this._rangeDecoder.decodeBit(this._isRepG0Decoders, state) === 0){
          if (this._rangeDecoder.decodeBit(this._isRep0LongDecoders, (state << 4) + posState) === 0){
            state = state < 7? 9: 11;
            len = 1;
          }
        }else{
          if (this._rangeDecoder.decodeBit(this._isRepG1Decoders, state) === 0){
            distance = rep1;
          }else{
            if (this._rangeDecoder.decodeBit(this._isRepG2Decoders, state) === 0){
              distance = rep2;
            }else{
              distance = rep3;
              rep3 = rep2;
            }
            rep2 = rep1;
          }
          rep1 = rep0;
          rep0 = distance;
        }
        if (len === 0){
          len = 2 + this._repLenDecoder.decode(this._rangeDecoder, posState);
          state = state < 7? 8: 11;
        }
      }else{
        rep3 = rep2;
        rep2 = rep1;
        rep1 = rep0;

        len = 2 + this._lenDecoder.decode(this._rangeDecoder, posState);
        state = state < 7? 7: 10;

        posSlot = this._posSlotDecoder[len <= 5? len - 2: 3].decode(this._rangeDecoder);
        if (posSlot >= 4){

          numDirectBits = (posSlot >> 1) - 1;
          rep0 = (2 | (posSlot & 1) ) << numDirectBits;

          if (posSlot < 14){
            rep0 += LZMA.reverseDecode2(this._posDecoders,
                rep0 - posSlot - 1, this._rangeDecoder, numDirectBits);
          }else{
            rep0 += this._rangeDecoder.decodeDirectBits(numDirectBits - 4) << 4;
            rep0 += this._posAlignDecoder.reverseDecode(this._rangeDecoder);
            if (rep0 < 0){
              if (rep0 === -1){
                break;
              }
              return false;
            }
          }
        }else{
          rep0 = posSlot;
        }
      }

      if (rep0 >= nowPos64 || rep0 >= this._dictionarySizeCheck){
        return false;
      }

      this._outWindow.copyBlock(rep0, len);
      nowPos64 += len;
      prevByte = this._outWindow.getByte(0);
    }
  }

  this._outWindow.flush();
  this._outWindow.releaseStream();
  this._rangeDecoder.releaseStream();

  return true;
};

LZMA.Decoder.prototype.setDecoderProperties = function(properties){
  var value, lc, lp, pb, dictionarySize;

  if (properties.size < 5){
    return false;
  }

  value = properties.readByte();
  lc = value % 9;
  value = ~~(value / 9);
  lp = value % 5;
  pb = ~~(value / 5);

  if ( !this.setLcLpPb(lc, lp, pb) ){
    return false;
  }

  dictionarySize = properties.readByte();
  dictionarySize |= properties.readByte() << 8;
  dictionarySize |= properties.readByte() << 16;
  dictionarySize += properties.readByte() * 16777216;

  return this.setDictionarySize(dictionarySize);
};

LZMA.decompress = function(properties, inStream, outStream, outSize){
  var decoder = new LZMA.Decoder();

  if ( !decoder.setDecoderProperties(properties) ){
    throw "Incorrect stream properties";
  }

  if ( !decoder.decode(inStream, outStream, outSize) ){
    throw "Error in data stream";
  }

  return true;
};

exports.LZMA = LZMA;