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lzma-purejs-requirejs

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pure JavaScript LZMA de/compression, for node.js, volo, and the browser.

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'use strict'; const Base = require('./Base'); const LZ = require('../LZ'); const RangeCoder = require('../RangeCoder'); /* Copyright (c) 2011 Juan Mellado Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ /* References: - "LZMA SDK" by Igor Pavlov http://www.7-zip.org/sdk.html */ /* Original source found at: http://code.google.com/p/js-lzma/ */ // shortcuts var initBitModels = RangeCoder.Encoder.initBitModels; var LenDecoder = function(){ this._choice = initBitModels(null, 2); this._lowCoder = []; this._midCoder = []; this._highCoder = new RangeCoder.BitTreeDecoder(8); this._numPosStates = 0; }; LenDecoder.prototype.create = function(numPosStates){ for (; this._numPosStates < numPosStates; ++ this._numPosStates){ this._lowCoder[this._numPosStates] = new RangeCoder.BitTreeDecoder(3); this._midCoder[this._numPosStates] = new RangeCoder.BitTreeDecoder(3); } }; LenDecoder.prototype.init = function(){ var i = this._numPosStates; initBitModels(this._choice); while(i --){ this._lowCoder[i].init(); this._midCoder[i].init(); } this._highCoder.init(); }; 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); }; var LiteralDecoder = function(){ }; LiteralDecoder.Decoder2 = function(){ this._decoders = initBitModels(null, 0x300); }; LiteralDecoder.Decoder2.prototype.init = function(){ initBitModels(this._decoders); }; LiteralDecoder.Decoder2.prototype.decodeNormal = function(rangeDecoder){ var symbol = 1; do{ symbol = (symbol << 1) | rangeDecoder.decodeBit(this._decoders, symbol); }while(symbol < 0x100); return symbol & 0xff; }; LiteralDecoder.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; }; 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 LiteralDecoder.Decoder2(); } }; LiteralDecoder.prototype.init = function(){ var i = 1 << (this._numPrevBits + this._numPosBits); while(i --){ this._coders[i].init(); } }; LiteralDecoder.prototype.getDecoder = function(pos, prevByte){ return this._coders[( (pos & this._posMask) << this._numPrevBits) + ( (prevByte & 0xff) >>> (8 - this._numPrevBits) )]; }; var Decoder = function(){ var i; this._outWindow = new LZ.OutWindow(); this._rangeDecoder = new RangeCoder.Decoder(); this._isMatchDecoders = initBitModels(null, Base.kNumStates << Base.kNumPosStatesBitsMax); this._isRepDecoders = initBitModels(null, Base.kNumStates); this._isRepG0Decoders = initBitModels(null, Base.kNumStates); this._isRepG1Decoders = initBitModels(null, Base.kNumStates); this._isRepG2Decoders = initBitModels(null, Base.kNumStates); this._isRep0LongDecoders = initBitModels(null, Base.kNumStates << Base.kNumPosStatesBitsMax); this._posSlotDecoder = []; this._posDecoders = initBitModels(null, Base.kNumFullDistances - Base.kEndPosModelIndex); this._posAlignDecoder = new RangeCoder.BitTreeDecoder(Base.kNumAlignBits); this._lenDecoder = new LenDecoder(); this._repLenDecoder = new LenDecoder(); this._literalDecoder = new LiteralDecoder(); this._dictionarySize = -1; this._dictionarySizeCheck = -1; this._posStateMask = 0; for (i=0; i<Base.kNumLenToPosStates; i++) { this._posSlotDecoder[i] = new RangeCoder.BitTreeDecoder(Base.kNumPosSlotBits); } }; 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, (1 << 12)) ); } return true; }; Decoder.prototype.setLcLpPb = function(lc, lp, pb){ var numPosStates = 1 << pb; if (lc > Base.kNumLitContextBitsMax || lp > 4 || pb > Base.kNumPosStatesBitsMax){ return false; } this._literalDecoder.create(lp, lc); this._lenDecoder.create(numPosStates); this._repLenDecoder.create(numPosStates); this._posStateMask = numPosStates - 1; return true; }; Decoder.prototype.init = function(){ var i = Base.kNumLenToPosStates; this._outWindow.init(false); initBitModels(this._isMatchDecoders); initBitModels(this._isRepDecoders); initBitModels(this._isRepG0Decoders); initBitModels(this._isRepG1Decoders); initBitModels(this._isRepG2Decoders); initBitModels(this._isRep0LongDecoders); initBitModels(this._posDecoders); this._literalDecoder.init(); while(i --){ this._posSlotDecoder[i].init(); } this._lenDecoder.init(); this._repLenDecoder.init(); this._posAlignDecoder.init(); this._rangeDecoder.init(); }; Decoder.prototype.code = function(inStream, outStream, outSize){ // note that nowPos64 is actually only 53 bits long; that sets a limit // on the amount of data we can decode var state, 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(); state = Base.stateInit(); while(outSize < 0 || nowPos64 < outSize){ posState = nowPos64 & this._posStateMask; if (this._rangeDecoder.decodeBit(this._isMatchDecoders, (state << Base.kNumPosStatesBitsMax) + posState) === 0){ decoder2 = this._literalDecoder.getDecoder(nowPos64, prevByte); if (!Base.stateIsCharState(state)){ prevByte = decoder2.decodeWithMatchByte(this._rangeDecoder, this._outWindow.getByte(rep0) ); }else{ prevByte = decoder2.decodeNormal(this._rangeDecoder); } this._outWindow.putByte(prevByte); state = Base.stateUpdateChar(state); nowPos64++; }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 << Base.kNumPosStatesBitsMax) + posState) === 0){ state = Base.stateUpdateShortRep(state); 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 = Base.kMatchMinLen + this._repLenDecoder.decode(this._rangeDecoder, posState); state = Base.stateUpdateRep(state); } }else{ rep3 = rep2; rep2 = rep1; rep1 = rep0; len = Base.kMatchMinLen + this._lenDecoder.decode(this._rangeDecoder, posState); state = Base.stateUpdateMatch(state); posSlot = this._posSlotDecoder[Base.getLenToPosState(len)].decode(this._rangeDecoder); if (posSlot >= Base.kStartPosModelIndex){ numDirectBits = (posSlot >> 1) - 1; rep0 = (2 | (posSlot & 1) ) << numDirectBits; if (posSlot < Base.kEndPosModelIndex){ rep0 += RangeCoder.BitTreeDecoder.reverseDecode(this._posDecoders, rep0 - posSlot - 1, this._rangeDecoder, numDirectBits); }else{ rep0 += this._rangeDecoder.decodeDirectBits(numDirectBits - Base.kNumAlignBits) << Base.kNumAlignBits; 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; }; Decoder.prototype.setDecoderProperties = function(properties){ var value, lc, lp, pb, dictionarySize, i, shift; if (properties.length < 5){ return false; } value = properties[0] & 0xFF; lc = value % 9; value = ~~(value / 9); lp = value % 5; pb = ~~(value / 5); if ( !this.setLcLpPb(lc, lp, pb) ){ return false; } dictionarySize = 0; for (i=0, shift=1; i<4; i++, shift*=256) dictionarySize += (properties[1+i] & 0xFF) * shift; return this.setDictionarySize(dictionarySize); }; Decoder.prototype.setDecoderPropertiesFromStream = function(stream) { var buffer = [], i; for (i=0; i<5; i++) { buffer[i] = stream.readByte(); } return this.setDecoderProperties(buffer); }; module.exports = Decoder;