package SevenZip.Compression.LZMA; import java.io.IOException; import SevenZip.Compression.LZ.OutWindow; import SevenZip.Compression.RangeCoder.BitTreeDecoder; public class Decoder { class LenDecoder { short[] m_Choice = new short[2]; BitTreeDecoder[] m_LowCoder = new BitTreeDecoder[Base.kNumPosStatesMax]; BitTreeDecoder[] m_MidCoder = new BitTreeDecoder[Base.kNumPosStatesMax]; BitTreeDecoder m_HighCoder = new BitTreeDecoder( Base.kNumHighLenBits); int m_NumPosStates = 0; public void Create(int numPosStates) { for (; m_NumPosStates < numPosStates; m_NumPosStates++) { m_LowCoder[m_NumPosStates] = new BitTreeDecoder( Base.kNumLowLenBits); m_MidCoder[m_NumPosStates] = new BitTreeDecoder( Base.kNumMidLenBits); } } public void Init() { SevenZip.Compression.RangeCoder.Decoder.InitBitModels(m_Choice); for (int posState = 0; posState < m_NumPosStates; posState++) { m_LowCoder[posState].Init(); m_MidCoder[posState].Init(); } m_HighCoder.Init(); } public int Decode(SevenZip.Compression.RangeCoder.Decoder rangeDecoder, int posState) throws IOException { if (rangeDecoder.DecodeBit(m_Choice, 0) == 0) { return m_LowCoder[posState].Decode(rangeDecoder); } int symbol = Base.kNumLowLenSymbols; if (rangeDecoder.DecodeBit(m_Choice, 1) == 0) { symbol += m_MidCoder[posState].Decode(rangeDecoder); } else { symbol += Base.kNumMidLenSymbols + m_HighCoder.Decode(rangeDecoder); } return symbol; } } class LiteralDecoder { class Decoder2 { short[] m_Decoders = new short[0x300]; public void Init() { SevenZip.Compression.RangeCoder.Decoder .InitBitModels(m_Decoders); } public byte DecodeNormal( SevenZip.Compression.RangeCoder.Decoder rangeDecoder) throws IOException { int symbol = 1; do { symbol = symbol << 1 | rangeDecoder.DecodeBit(m_Decoders, symbol); } while (symbol < 0x100); return (byte) symbol; } public byte DecodeWithMatchByte( SevenZip.Compression.RangeCoder.Decoder rangeDecoder, byte matchByte) throws IOException { int symbol = 1; do { final int matchBit = matchByte >> 7 & 1; matchByte <<= 1; final int bit = rangeDecoder.DecodeBit(m_Decoders, (1 + matchBit << 8) + symbol); symbol = symbol << 1 | bit; if (matchBit != bit) { while (symbol < 0x100) { symbol = symbol << 1 | rangeDecoder .DecodeBit(m_Decoders, symbol); } break; } } while (symbol < 0x100); return (byte) symbol; } } Decoder2[] m_Coders; int m_NumPrevBits; int m_NumPosBits; int m_PosMask; public void Create(int numPosBits, int numPrevBits) { if (m_Coders != null && m_NumPrevBits == numPrevBits && m_NumPosBits == numPosBits) { return; } m_NumPosBits = numPosBits; m_PosMask = (1 << numPosBits) - 1; m_NumPrevBits = numPrevBits; final int numStates = 1 << m_NumPrevBits + m_NumPosBits; m_Coders = new Decoder2[numStates]; for (int i = 0; i < numStates; i++) { m_Coders[i] = new Decoder2(); } } public void Init() { final int numStates = 1 << m_NumPrevBits + m_NumPosBits; for (int i = 0; i < numStates; i++) { m_Coders[i].Init(); } } Decoder2 GetDecoder(int pos, byte prevByte) { return m_Coders[((pos & m_PosMask) << m_NumPrevBits) + ((prevByte & 0xFF) >>> 8 - m_NumPrevBits)]; } } OutWindow m_OutWindow = new OutWindow(); SevenZip.Compression.RangeCoder.Decoder m_RangeDecoder = new SevenZip.Compression.RangeCoder.Decoder(); short[] m_IsMatchDecoders = new short[Base.kNumStates << Base.kNumPosStatesBitsMax]; short[] m_IsRepDecoders = new short[Base.kNumStates]; short[] m_IsRepG0Decoders = new short[Base.kNumStates]; short[] m_IsRepG1Decoders = new short[Base.kNumStates]; short[] m_IsRepG2Decoders = new short[Base.kNumStates]; short[] m_IsRep0LongDecoders = new short[Base.kNumStates << Base.kNumPosStatesBitsMax]; BitTreeDecoder[] m_PosSlotDecoder = new BitTreeDecoder[Base.kNumLenToPosStates]; short[] m_PosDecoders = new short[Base.kNumFullDistances - Base.kEndPosModelIndex]; BitTreeDecoder m_PosAlignDecoder = new BitTreeDecoder( Base.kNumAlignBits); LenDecoder m_LenDecoder = new LenDecoder(); LenDecoder m_RepLenDecoder = new LenDecoder(); LiteralDecoder m_LiteralDecoder = new LiteralDecoder(); int m_DictionarySize = -1; int m_DictionarySizeCheck = -1; int m_PosStateMask; public Decoder() { for (int i = 0; i < Base.kNumLenToPosStates; i++) { m_PosSlotDecoder[i] = new BitTreeDecoder(Base.kNumPosSlotBits); } } boolean SetDictionarySize(int dictionarySize) { if (dictionarySize < 0) { return false; } if (m_DictionarySize != dictionarySize) { m_DictionarySize = dictionarySize; m_DictionarySizeCheck = Math.max(m_DictionarySize, 1); m_OutWindow.Create(Math.max(m_DictionarySizeCheck, 1 << 12)); } return true; } boolean SetLcLpPb(int lc, int lp, int pb) { if (lc > Base.kNumLitContextBitsMax || lp > 4 || pb > Base.kNumPosStatesBitsMax) { return false; } m_LiteralDecoder.Create(lp, lc); final int numPosStates = 1 << pb; m_LenDecoder.Create(numPosStates); m_RepLenDecoder.Create(numPosStates); m_PosStateMask = numPosStates - 1; return true; } void Init() throws IOException { m_OutWindow.Init(false); SevenZip.Compression.RangeCoder.Decoder .InitBitModels(m_IsMatchDecoders); SevenZip.Compression.RangeCoder.Decoder .InitBitModels(m_IsRep0LongDecoders); SevenZip.Compression.RangeCoder.Decoder.InitBitModels(m_IsRepDecoders); SevenZip.Compression.RangeCoder.Decoder .InitBitModels(m_IsRepG0Decoders); SevenZip.Compression.RangeCoder.Decoder .InitBitModels(m_IsRepG1Decoders); SevenZip.Compression.RangeCoder.Decoder .InitBitModels(m_IsRepG2Decoders); SevenZip.Compression.RangeCoder.Decoder.InitBitModels(m_PosDecoders); m_LiteralDecoder.Init(); int i; for (i = 0; i < Base.kNumLenToPosStates; i++) { m_PosSlotDecoder[i].Init(); } m_LenDecoder.Init(); m_RepLenDecoder.Init(); m_PosAlignDecoder.Init(); m_RangeDecoder.Init(); } public boolean Code(java.io.InputStream inStream, java.io.OutputStream outStream, long outSize) throws IOException { m_RangeDecoder.SetStream(inStream); m_OutWindow.SetStream(outStream); Init(); int state = Base.StateInit(); int rep0 = 0, rep1 = 0, rep2 = 0, rep3 = 0; long nowPos64 = 0; byte prevByte = 0; while (outSize < 0 || nowPos64 < outSize) { final int posState = (int) nowPos64 & m_PosStateMask; if (m_RangeDecoder.DecodeBit(m_IsMatchDecoders, (state << Base.kNumPosStatesBitsMax) + posState) == 0) { final LiteralDecoder.Decoder2 decoder2 = m_LiteralDecoder .GetDecoder((int) nowPos64, prevByte); if (!Base.StateIsCharState(state)) { prevByte = decoder2.DecodeWithMatchByte(m_RangeDecoder, m_OutWindow.GetByte(rep0)); } else { prevByte = decoder2.DecodeNormal(m_RangeDecoder); } m_OutWindow.PutByte(prevByte); state = Base.StateUpdateChar(state); nowPos64++; } else { int len; if (m_RangeDecoder.DecodeBit(m_IsRepDecoders, state) == 1) { len = 0; if (m_RangeDecoder.DecodeBit(m_IsRepG0Decoders, state) == 0) { if (m_RangeDecoder .DecodeBit(m_IsRep0LongDecoders, (state << Base.kNumPosStatesBitsMax) + posState) == 0) { state = Base.StateUpdateShortRep(state); len = 1; } } else { int distance; if (m_RangeDecoder.DecodeBit(m_IsRepG1Decoders, state) == 0) { distance = rep1; } else { if (m_RangeDecoder.DecodeBit(m_IsRepG2Decoders, state) == 0) { distance = rep2; } else { distance = rep3; rep3 = rep2; } rep2 = rep1; } rep1 = rep0; rep0 = distance; } if (len == 0) { len = m_RepLenDecoder.Decode(m_RangeDecoder, posState) + Base.kMatchMinLen; state = Base.StateUpdateRep(state); } } else { rep3 = rep2; rep2 = rep1; rep1 = rep0; len = Base.kMatchMinLen + m_LenDecoder.Decode(m_RangeDecoder, posState); state = Base.StateUpdateMatch(state); final int posSlot = m_PosSlotDecoder[Base .GetLenToPosState(len)].Decode(m_RangeDecoder); if (posSlot >= Base.kStartPosModelIndex) { final int numDirectBits = (posSlot >> 1) - 1; rep0 = (2 | posSlot & 1) << numDirectBits; if (posSlot < Base.kEndPosModelIndex) { rep0 += BitTreeDecoder.ReverseDecode(m_PosDecoders, rep0 - posSlot - 1, m_RangeDecoder, numDirectBits); } else { rep0 += m_RangeDecoder .DecodeDirectBits(numDirectBits - Base.kNumAlignBits) << Base.kNumAlignBits; rep0 += m_PosAlignDecoder .ReverseDecode(m_RangeDecoder); if (rep0 < 0) { if (rep0 == -1) { break; } return false; } } } else { rep0 = posSlot; } } if (rep0 >= nowPos64 || rep0 >= m_DictionarySizeCheck) { // m_OutWindow.Flush(); return false; } m_OutWindow.CopyBlock(rep0, len); nowPos64 += len; prevByte = m_OutWindow.GetByte(0); } } m_OutWindow.Flush(); m_OutWindow.ReleaseStream(); m_RangeDecoder.ReleaseStream(); return true; } public boolean SetDecoderProperties(byte[] properties) { if (properties.length < 5) { return false; } final int val = properties[0] & 0xFF; final int lc = val % 9; final int remainder = val / 9; final int lp = remainder % 5; final int pb = remainder / 5; int dictionarySize = 0; for (int i = 0; i < 4; i++) { dictionarySize += (properties[1 + i] & 0xFF) << i * 8; } if (!SetLcLpPb(lc, lp, pb)) { return false; } return SetDictionarySize(dictionarySize); } }