1 package SevenZip.Compression.LZMA; 2 3 import SevenZip.Compression.RangeCoder.BitTreeDecoder; 4 import SevenZip.Compression.LZMA.Base; 5 import SevenZip.Compression.LZ.OutWindow; 6 import java.io.IOException; 7 8 public class Decoder 9 { 10 class LenDecoder 11 { 12 short[] m_Choice = new short[2]; 13 BitTreeDecoder[] m_LowCoder = new BitTreeDecoder[Base.kNumPosStatesMax]; 14 BitTreeDecoder[] m_MidCoder = new BitTreeDecoder[Base.kNumPosStatesMax]; 15 BitTreeDecoder m_HighCoder = new BitTreeDecoder(Base.kNumHighLenBits); 16 int m_NumPosStates = 0; 17 18 public void Create(int numPosStates) 19 { 20 for (; m_NumPosStates < numPosStates; m_NumPosStates++) 21 { 22 m_LowCoder[m_NumPosStates] = new BitTreeDecoder(Base.kNumLowLenBits); 23 m_MidCoder[m_NumPosStates] = new BitTreeDecoder(Base.kNumMidLenBits); 24 } 25 } 26 27 public void Init() 28 { 29 SevenZip.Compression.RangeCoder.Decoder.InitBitModels(m_Choice); 30 for (int posState = 0; posState < m_NumPosStates; posState++) 31 { 32 m_LowCoder[posState].Init(); 33 m_MidCoder[posState].Init(); 34 } 35 m_HighCoder.Init(); 36 } 37 38 public int Decode(SevenZip.Compression.RangeCoder.Decoder rangeDecoder, int posState) throws IOException 39 { 40 if (rangeDecoder.DecodeBit(m_Choice, 0) == 0) 41 return m_LowCoder[posState].Decode(rangeDecoder); 42 int symbol = Base.kNumLowLenSymbols; 43 if (rangeDecoder.DecodeBit(m_Choice, 1) == 0) 44 symbol += m_MidCoder[posState].Decode(rangeDecoder); 45 else 46 symbol += Base.kNumMidLenSymbols + m_HighCoder.Decode(rangeDecoder); 47 return symbol; 48 } 49 } 50 51 class LiteralDecoder 52 { 53 class Decoder2 54 { 55 short[] m_Decoders = new short[0x300]; 56 57 public void Init() 58 { 59 SevenZip.Compression.RangeCoder.Decoder.InitBitModels(m_Decoders); 60 } 61 62 public byte DecodeNormal(SevenZip.Compression.RangeCoder.Decoder rangeDecoder) throws IOException 63 { 64 int symbol = 1; 65 do 66 symbol = (symbol << 1) | rangeDecoder.DecodeBit(m_Decoders, symbol); 67 while (symbol < 0x100); 68 return (byte)symbol; 69 } 70 71 public byte DecodeWithMatchByte(SevenZip.Compression.RangeCoder.Decoder rangeDecoder, byte matchByte) throws IOException 72 { 73 int symbol = 1; 74 do 75 { 76 int matchBit = (matchByte >> 7) & 1; 77 matchByte <<= 1; 78 int bit = rangeDecoder.DecodeBit(m_Decoders, ((1 + matchBit) << 8) + symbol); 79 symbol = (symbol << 1) | bit; 80 if (matchBit != bit) 81 { 82 while (symbol < 0x100) 83 symbol = (symbol << 1) | rangeDecoder.DecodeBit(m_Decoders, symbol); 84 break; 85 } 86 } 87 while (symbol < 0x100); 88 return (byte)symbol; 89 } 90 } 91 92 Decoder2[] m_Coders; 93 int m_NumPrevBits; 94 int m_NumPosBits; 95 int m_PosMask; 96 97 public void Create(int numPosBits, int numPrevBits) 98 { 99 if (m_Coders != null && m_NumPrevBits == numPrevBits && m_NumPosBits == numPosBits) 100 return; 101 m_NumPosBits = numPosBits; 102 m_PosMask = (1 << numPosBits) - 1; 103 m_NumPrevBits = numPrevBits; 104 int numStates = 1 << (m_NumPrevBits + m_NumPosBits); 105 m_Coders = new Decoder2[numStates]; 106 for (int i = 0; i < numStates; i++) 107 m_Coders[i] = new Decoder2(); 108 } 109 110 public void Init() 111 { 112 int numStates = 1 << (m_NumPrevBits + m_NumPosBits); 113 for (int i = 0; i < numStates; i++) 114 m_Coders[i].Init(); 115 } 116 117 Decoder2 GetDecoder(int pos, byte prevByte) 118 { 119 return m_Coders[((pos & m_PosMask) << m_NumPrevBits) + ((prevByte & 0xFF) >>> (8 - m_NumPrevBits))]; 120 } 121 } 122 123 OutWindow m_OutWindow = new OutWindow(); 124 SevenZip.Compression.RangeCoder.Decoder m_RangeDecoder = new SevenZip.Compression.RangeCoder.Decoder(); 125 126 short[] m_IsMatchDecoders = new short[Base.kNumStates << Base.kNumPosStatesBitsMax]; 127 short[] m_IsRepDecoders = new short[Base.kNumStates]; 128 short[] m_IsRepG0Decoders = new short[Base.kNumStates]; 129 short[] m_IsRepG1Decoders = new short[Base.kNumStates]; 130 short[] m_IsRepG2Decoders = new short[Base.kNumStates]; 131 short[] m_IsRep0LongDecoders = new short[Base.kNumStates << Base.kNumPosStatesBitsMax]; 132 133 BitTreeDecoder[] m_PosSlotDecoder = new BitTreeDecoder[Base.kNumLenToPosStates]; 134 short[] m_PosDecoders = new short[Base.kNumFullDistances - Base.kEndPosModelIndex]; 135 136 BitTreeDecoder m_PosAlignDecoder = new BitTreeDecoder(Base.kNumAlignBits); 137 138 LenDecoder m_LenDecoder = new LenDecoder(); 139 LenDecoder m_RepLenDecoder = new LenDecoder(); 140 141 LiteralDecoder m_LiteralDecoder = new LiteralDecoder(); 142 143 int m_DictionarySize = -1; 144 int m_DictionarySizeCheck = -1; 145 146 int m_PosStateMask; 147 148 public Decoder() 149 { 150 for (int i = 0; i < Base.kNumLenToPosStates; i++) 151 m_PosSlotDecoder[i] = new BitTreeDecoder(Base.kNumPosSlotBits); 152 } 153 154 boolean SetDictionarySize(int dictionarySize) 155 { 156 if (dictionarySize < 0) 157 return false; 158 if (m_DictionarySize != dictionarySize) 159 { 160 m_DictionarySize = dictionarySize; 161 m_DictionarySizeCheck = Math.max(m_DictionarySize, 1); 162 m_OutWindow.Create(Math.max(m_DictionarySizeCheck, (1 << 12))); 163 } 164 return true; 165 } 166 167 boolean SetLcLpPb(int lc, int lp, int pb) 168 { 169 if (lc > Base.kNumLitContextBitsMax || lp > 4 || pb > Base.kNumPosStatesBitsMax) 170 return false; 171 m_LiteralDecoder.Create(lp, lc); 172 int numPosStates = 1 << pb; 173 m_LenDecoder.Create(numPosStates); 174 m_RepLenDecoder.Create(numPosStates); 175 m_PosStateMask = numPosStates - 1; 176 return true; 177 } 178 179 void Init() throws IOException 180 { 181 m_OutWindow.Init(false); 182 183 SevenZip.Compression.RangeCoder.Decoder.InitBitModels(m_IsMatchDecoders); 184 SevenZip.Compression.RangeCoder.Decoder.InitBitModels(m_IsRep0LongDecoders); 185 SevenZip.Compression.RangeCoder.Decoder.InitBitModels(m_IsRepDecoders); 186 SevenZip.Compression.RangeCoder.Decoder.InitBitModels(m_IsRepG0Decoders); 187 SevenZip.Compression.RangeCoder.Decoder.InitBitModels(m_IsRepG1Decoders); 188 SevenZip.Compression.RangeCoder.Decoder.InitBitModels(m_IsRepG2Decoders); 189 SevenZip.Compression.RangeCoder.Decoder.InitBitModels(m_PosDecoders); 190 191 m_LiteralDecoder.Init(); 192 int i; 193 for (i = 0; i < Base.kNumLenToPosStates; i++) 194 m_PosSlotDecoder[i].Init(); 195 m_LenDecoder.Init(); 196 m_RepLenDecoder.Init(); 197 m_PosAlignDecoder.Init(); 198 m_RangeDecoder.Init(); 199 } 200 201 public boolean Code(java.io.InputStream inStream, java.io.OutputStream outStream, 202 long outSize) throws IOException 203 { 204 m_RangeDecoder.SetStream(inStream); 205 m_OutWindow.SetStream(outStream); 206 Init(); 207 208 int state = Base.StateInit(); 209 int rep0 = 0, rep1 = 0, rep2 = 0, rep3 = 0; 210 211 long nowPos64 = 0; 212 byte prevByte = 0; 213 while (outSize < 0 || nowPos64 < outSize) 214 { 215 int posState = (int)nowPos64 & m_PosStateMask; 216 if (m_RangeDecoder.DecodeBit(m_IsMatchDecoders, (state << Base.kNumPosStatesBitsMax) + posState) == 0) 217 { 218 LiteralDecoder.Decoder2 decoder2 = m_LiteralDecoder.GetDecoder((int)nowPos64, prevByte); 219 if (!Base.StateIsCharState(state)) 220 prevByte = decoder2.DecodeWithMatchByte(m_RangeDecoder, m_OutWindow.GetByte(rep0)); 221 else 222 prevByte = decoder2.DecodeNormal(m_RangeDecoder); 223 m_OutWindow.PutByte(prevByte); 224 state = Base.StateUpdateChar(state); 225 nowPos64++; 226 } 227 else 228 { 229 int len; 230 if (m_RangeDecoder.DecodeBit(m_IsRepDecoders, state) == 1) 231 { 232 len = 0; 233 if (m_RangeDecoder.DecodeBit(m_IsRepG0Decoders, state) == 0) 234 { 235 if (m_RangeDecoder.DecodeBit(m_IsRep0LongDecoders, (state << Base.kNumPosStatesBitsMax) + posState) == 0) 236 { 237 state = Base.StateUpdateShortRep(state); 238 len = 1; 239 } 240 } 241 else 242 { 243 int distance; 244 if (m_RangeDecoder.DecodeBit(m_IsRepG1Decoders, state) == 0) 245 distance = rep1; 246 else 247 { 248 if (m_RangeDecoder.DecodeBit(m_IsRepG2Decoders, state) == 0) 249 distance = rep2; 250 else 251 { 252 distance = rep3; 253 rep3 = rep2; 254 } 255 rep2 = rep1; 256 } 257 rep1 = rep0; 258 rep0 = distance; 259 } 260 if (len == 0) 261 { 262 len = m_RepLenDecoder.Decode(m_RangeDecoder, posState) + Base.kMatchMinLen; 263 state = Base.StateUpdateRep(state); 264 } 265 } 266 else 267 { 268 rep3 = rep2; 269 rep2 = rep1; 270 rep1 = rep0; 271 len = Base.kMatchMinLen + m_LenDecoder.Decode(m_RangeDecoder, posState); 272 state = Base.StateUpdateMatch(state); 273 int posSlot = m_PosSlotDecoder[Base.GetLenToPosState(len)].Decode(m_RangeDecoder); 274 if (posSlot >= Base.kStartPosModelIndex) 275 { 276 int numDirectBits = (posSlot >> 1) - 1; 277 rep0 = ((2 | (posSlot & 1)) << numDirectBits); 278 if (posSlot < Base.kEndPosModelIndex) 279 rep0 += BitTreeDecoder.ReverseDecode(m_PosDecoders, 280 rep0 - posSlot - 1, m_RangeDecoder, numDirectBits); 281 else 282 { 283 rep0 += (m_RangeDecoder.DecodeDirectBits( 284 numDirectBits - Base.kNumAlignBits) << Base.kNumAlignBits); 285 rep0 += m_PosAlignDecoder.ReverseDecode(m_RangeDecoder); 286 if (rep0 < 0) 287 { 288 if (rep0 == -1) 289 break; 290 return false; 291 } 292 } 293 } 294 else 295 rep0 = posSlot; 296 } 297 if (rep0 >= nowPos64 || rep0 >= m_DictionarySizeCheck) 298 { 299 // m_OutWindow.Flush(); 300 return false; 301 } 302 m_OutWindow.CopyBlock(rep0, len); 303 nowPos64 += len; 304 prevByte = m_OutWindow.GetByte(0); 305 } 306 } 307 m_OutWindow.Flush(); 308 m_OutWindow.ReleaseStream(); 309 m_RangeDecoder.ReleaseStream(); 310 return true; 311 } 312 313 public boolean SetDecoderProperties(byte[] properties) 314 { 315 if (properties.length < 5) 316 return false; 317 int val = properties[0] & 0xFF; 318 int lc = val % 9; 319 int remainder = val / 9; 320 int lp = remainder % 5; 321 int pb = remainder / 5; 322 int dictionarySize = 0; 323 for (int i = 0; i < 4; i++) 324 dictionarySize += ((int)(properties[1 + i]) & 0xFF) << (i * 8); 325 if (!SetLcLpPb(lc, lp, pb)) 326 return false; 327 return SetDictionarySize(dictionarySize); 328 } 329 } 330
