lib/lzma/LzmaDec.c

   1 /* LzmaDec.c -- LZMA Decoder
   2 2008-11-06 : Igor Pavlov : Public domain */
   3
   4 #include <config.h>
   5 #include <common.h>
   6 #include <watchdog.h>
   7 #include "LzmaDec.h"
   8
   9 #include <linux/string.h>
  10
  11 #define kNumTopBits 24
  12 #define kTopValue ((UInt32)1 << kNumTopBits)
  13
  14 #define kNumBitModelTotalBits 11
  15 #define kBitModelTotal (1 << kNumBitModelTotalBits)
  16 #define kNumMoveBits 5
  17
  18 #define RC_INIT_SIZE 5
  19
  20 #define NORMALIZE if (range < kTopValue) { range <<= 8; code = (code << 8) | (*buf++); }
  21
  22 #define IF_BIT_0(p) ttt = *(p); NORMALIZE; bound = (range >> kNumBitModelTotalBits) * ttt; if (code < bound)
  23 #define UPDATE_0(p) range = bound; *(p) = (CLzmaProb)(ttt + ((kBitModelTotal - ttt) >> kNumMoveBits));
  24 #define UPDATE_1(p) range -= bound; code -= bound; *(p) = (CLzmaProb)(ttt - (ttt >> kNumMoveBits));
  25 #define GET_BIT2(p, i, A0, A1) IF_BIT_0(p) \
  26   { UPDATE_0(p); i = (i + i); A0; } else \
  27   { UPDATE_1(p); i = (i + i) + 1; A1; }
  28 #define GET_BIT(p, i) GET_BIT2(p, i, ; , ;)
  29
  30 #define TREE_GET_BIT(probs, i) { GET_BIT((probs + i), i); }
  31 #define TREE_DECODE(probs, limit, i) \
  32   { i = 1; do { TREE_GET_BIT(probs, i); } while (i < limit); i -= limit; }
  33
  34 /* #define _LZMA_SIZE_OPT */
  35
  36 #ifdef _LZMA_SIZE_OPT
  37 #define TREE_6_DECODE(probs, i) TREE_DECODE(probs, (1 << 6), i)
  38 #else
  39 #define TREE_6_DECODE(probs, i) \
  40   { i = 1; \
  41   TREE_GET_BIT(probs, i); \
  42   TREE_GET_BIT(probs, i); \
  43   TREE_GET_BIT(probs, i); \
  44   TREE_GET_BIT(probs, i); \
  45   TREE_GET_BIT(probs, i); \
  46   TREE_GET_BIT(probs, i); \
  47   i -= 0x40; }
  48 #endif
  49
  50 #define NORMALIZE_CHECK if (range < kTopValue) { if (buf >= bufLimit) return DUMMY_ERROR; range <<= 8; code = (code << 8) | (*buf++); }
  51
  52 #define IF_BIT_0_CHECK(p) ttt = *(p); NORMALIZE_CHECK; bound = (range >> kNumBitModelTotalBits) * ttt; if (code < bound)
  53 #define UPDATE_0_CHECK range = bound;
  54 #define UPDATE_1_CHECK range -= bound; code -= bound;
  55 #define GET_BIT2_CHECK(p, i, A0, A1) IF_BIT_0_CHECK(p) \
  56   { UPDATE_0_CHECK; i = (i + i); A0; } else \
  57   { UPDATE_1_CHECK; i = (i + i) + 1; A1; }
  58 #define GET_BIT_CHECK(p, i) GET_BIT2_CHECK(p, i, ; , ;)
  59 #define TREE_DECODE_CHECK(probs, limit, i) \
  60   { i = 1; do { GET_BIT_CHECK(probs + i, i) } while (i < limit); i -= limit; }
  61
  62
  63 #define kNumPosBitsMax 4
  64 #define kNumPosStatesMax (1 << kNumPosBitsMax)
  65
  66 #define kLenNumLowBits 3
  67 #define kLenNumLowSymbols (1 << kLenNumLowBits)
  68 #define kLenNumMidBits 3
  69 #define kLenNumMidSymbols (1 << kLenNumMidBits)
  70 #define kLenNumHighBits 8
  71 #define kLenNumHighSymbols (1 << kLenNumHighBits)
  72
  73 #define LenChoice 0
  74 #define LenChoice2 (LenChoice + 1)
  75 #define LenLow (LenChoice2 + 1)
  76 #define LenMid (LenLow + (kNumPosStatesMax << kLenNumLowBits))
  77 #define LenHigh (LenMid + (kNumPosStatesMax << kLenNumMidBits))
  78 #define kNumLenProbs (LenHigh + kLenNumHighSymbols)
  79
  80
  81 #define kNumStates 12
  82 #define kNumLitStates 7
  83
  84 #define kStartPosModelIndex 4
  85 #define kEndPosModelIndex 14
  86 #define kNumFullDistances (1 << (kEndPosModelIndex >> 1))
  87
  88 #define kNumPosSlotBits 6
  89 #define kNumLenToPosStates 4
  90
  91 #define kNumAlignBits 4
  92 #define kAlignTableSize (1 << kNumAlignBits)
  93
  94 #define kMatchMinLen 2
  95 #define kMatchSpecLenStart (kMatchMinLen + kLenNumLowSymbols + kLenNumMidSymbols + kLenNumHighSymbols)
  96
  97 #define IsMatch 0
  98 #define IsRep (IsMatch + (kNumStates << kNumPosBitsMax))
  99 #define IsRepG0 (IsRep + kNumStates)
 100 #define IsRepG1 (IsRepG0 + kNumStates)
 101 #define IsRepG2 (IsRepG1 + kNumStates)
 102 #define IsRep0Long (IsRepG2 + kNumStates)
 103 #define PosSlot (IsRep0Long + (kNumStates << kNumPosBitsMax))
 104 #define SpecPos (PosSlot + (kNumLenToPosStates << kNumPosSlotBits))
 105 #define Align (SpecPos + kNumFullDistances - kEndPosModelIndex)
 106 #define LenCoder (Align + kAlignTableSize)
 107 #define RepLenCoder (LenCoder + kNumLenProbs)
 108 #define Literal (RepLenCoder + kNumLenProbs)
 109
 110 #define LZMA_BASE_SIZE 1846
 111 #define LZMA_LIT_SIZE 768
 112
 113 #define LzmaProps_GetNumProbs(p) ((UInt32)LZMA_BASE_SIZE + (LZMA_LIT_SIZE << ((p)->lc + (p)->lp)))
 114
 115 #if Literal != LZMA_BASE_SIZE
 116 StopCompilingDueBUG
 117 #endif
 118
 119 static const Byte kLiteralNextStates[kNumStates * 2] =
 120 {
 121   0, 0, 0, 0, 1, 2, 3,  4,  5,  6,  4,  5,
 122   7, 7, 7, 7, 7, 7, 7, 10, 10, 10, 10, 10
 123 };
 124
 125 #define LZMA_DIC_MIN (1 << 12)
 126
 127 /* First LZMA-symbol is always decoded.
 128 And it decodes new LZMA-symbols while (buf < bufLimit), but "buf" is without last normalization
 129 Out:
 130   Result:
 131     SZ_OK - OK
 132     SZ_ERROR_DATA - Error
 133   p->remainLen:
 134     < kMatchSpecLenStart : normal remain
 135     = kMatchSpecLenStart : finished
 136     = kMatchSpecLenStart + 1 : Flush marker
 137     = kMatchSpecLenStart + 2 : State Init Marker
 138 */
 139
 140 static int MY_FAST_CALL LzmaDec_DecodeReal(CLzmaDec *p, SizeT limit, const Byte *bufLimit)
 141 {
 142   CLzmaProb *probs = p->probs;
 143
 144   unsigned state = p->state;
 145   UInt32 rep0 = p->reps[0], rep1 = p->reps[1], rep2 = p->reps[2], rep3 = p->reps[3];
 146   unsigned pbMask = ((unsigned)1 << (p->prop.pb)) - 1;
 147   unsigned lpMask = ((unsigned)1 << (p->prop.lp)) - 1;
 148   unsigned lc = p->prop.lc;
 149
 150   Byte *dic = p->dic;
 151   SizeT dicBufSize = p->dicBufSize;
 152   SizeT dicPos = p->dicPos;
 153
 154   UInt32 processedPos = p->processedPos;
 155   UInt32 checkDicSize = p->checkDicSize;
 156   unsigned len = 0;
 157
 158   const Byte *buf = p->buf;
 159   UInt32 range = p->range;
 160   UInt32 code = p->code;
 161
 162   WATCHDOG_RESET();
 163
 164   do
 165   {
 166     CLzmaProb *prob;
 167     UInt32 bound;
 168     unsigned ttt;
 169     unsigned posState = processedPos & pbMask;
 170
 171     prob = probs + IsMatch + (state << kNumPosBitsMax) + posState;
 172     IF_BIT_0(prob)
 173     {
 174       unsigned symbol;
 175       UPDATE_0(prob);
 176       prob = probs + Literal;
 177       if (checkDicSize != 0 || processedPos != 0)
 178         prob += (LZMA_LIT_SIZE * (((processedPos & lpMask) << lc) +
 179         (dic[(dicPos == 0 ? dicBufSize : dicPos) - 1] >> (8 - lc))));
 180
 181       if (state < kNumLitStates)
 182       {
 183         symbol = 1;
 184
 185         WATCHDOG_RESET();
 186
 187         do { GET_BIT(prob + symbol, symbol) } while (symbol < 0x100);
 188       }
 189       else
 190       {
 191         unsigned matchByte = p->dic[(dicPos - rep0) + ((dicPos < rep0) ? dicBufSize : 0)];
 192         unsigned offs = 0x100;
 193         symbol = 1;
 194
 195         WATCHDOG_RESET();
 196
 197         do
 198         {
 199           unsigned bit;
 200           CLzmaProb *probLit;
 201           matchByte <<= 1;
 202           bit = (matchByte & offs);
 203           probLit = prob + offs + bit + symbol;
 204           GET_BIT2(probLit, symbol, offs &= ~bit, offs &= bit)
 205         }
 206         while (symbol < 0x100);
 207       }
 208       dic[dicPos++] = (Byte)symbol;
 209       processedPos++;
 210
 211       state = kLiteralNextStates[state];
 212       /* if (state < 4) state = 0; else if (state < 10) state -= 3; else state -= 6; */
 213       continue;
 214     }
 215     else
 216     {
 217       UPDATE_1(prob);
 218       prob = probs + IsRep + state;
 219       IF_BIT_0(prob)
 220       {
 221         UPDATE_0(prob);
 222         state += kNumStates;
 223         prob = probs + LenCoder;
 224       }
 225       else
 226       {
 227         UPDATE_1(prob);
 228         if (checkDicSize == 0 && processedPos == 0)
 229           return SZ_ERROR_DATA;
 230         prob = probs + IsRepG0 + state;
 231         IF_BIT_0(prob)
 232         {
 233           UPDATE_0(prob);
 234           prob = probs + IsRep0Long + (state << kNumPosBitsMax) + posState;
 235           IF_BIT_0(prob)
 236           {
 237             UPDATE_0(prob);
 238             dic[dicPos] = dic[(dicPos - rep0) + ((dicPos < rep0) ? dicBufSize : 0)];
 239             dicPos++;
 240             processedPos++;
 241             state = state < kNumLitStates ? 9 : 11;
 242             continue;
 243           }
 244           UPDATE_1(prob);
 245         }
 246         else
 247         {
 248           UInt32 distance;
 249           UPDATE_1(prob);
 250           prob = probs + IsRepG1 + state;
 251           IF_BIT_0(prob)
 252           {
 253             UPDATE_0(prob);
 254             distance = rep1;
 255           }
 256           else
 257           {
 258             UPDATE_1(prob);
 259             prob = probs + IsRepG2 + state;
 260             IF_BIT_0(prob)
 261             {
 262               UPDATE_0(prob);
 263               distance = rep2;
 264             }
 265             else
 266             {
 267               UPDATE_1(prob);
 268               distance = rep3;
 269               rep3 = rep2;
 270             }
 271             rep2 = rep1;
 272           }
 273           rep1 = rep0;
 274           rep0 = distance;
 275         }
 276         state = state < kNumLitStates ? 8 : 11;
 277         prob = probs + RepLenCoder;
 278       }
 279       {
 280         unsigned limit, offset;
 281         CLzmaProb *probLen = prob + LenChoice;
 282         IF_BIT_0(probLen)
 283         {
 284           UPDATE_0(probLen);
 285           probLen = prob + LenLow + (posState << kLenNumLowBits);
 286           offset = 0;
 287           limit = (1 << kLenNumLowBits);
 288         }
 289         else
 290         {
 291           UPDATE_1(probLen);
 292           probLen = prob + LenChoice2;
 293           IF_BIT_0(probLen)
 294           {
 295             UPDATE_0(probLen);
 296             probLen = prob + LenMid + (posState << kLenNumMidBits);
 297             offset = kLenNumLowSymbols;
 298             limit = (1 << kLenNumMidBits);
 299           }
 300           else
 301           {
 302             UPDATE_1(probLen);
 303             probLen = prob + LenHigh;
 304             offset = kLenNumLowSymbols + kLenNumMidSymbols;
 305             limit = (1 << kLenNumHighBits);
 306           }
 307         }
 308         TREE_DECODE(probLen, limit, len);
 309         len += offset;
 310       }
 311
 312       if (state >= kNumStates)
 313       {
 314         UInt32 distance;
 315         prob = probs + PosSlot +
 316             ((len < kNumLenToPosStates ? len : kNumLenToPosStates - 1) << kNumPosSlotBits);
 317         TREE_6_DECODE(prob, distance);
 318         if (distance >= kStartPosModelIndex)
 319         {
 320           unsigned posSlot = (unsigned)distance;
 321           int numDirectBits = (int)(((distance >> 1) - 1));
 322           distance = (2 | (distance & 1));
 323           if (posSlot < kEndPosModelIndex)
 324           {
 325             distance <<= numDirectBits;
 326             prob = probs + SpecPos + distance - posSlot - 1;
 327             {
 328               UInt32 mask = 1;
 329               unsigned i = 1;
 330
 331               WATCHDOG_RESET();
 332
 333               do
 334               {
 335                 GET_BIT2(prob + i, i, ; , distance |= mask);
 336                 mask <<= 1;
 337               }
 338               while (--numDirectBits != 0);
 339             }
 340           }
 341           else
 342           {
 343             numDirectBits -= kNumAlignBits;
 344
 345             WATCHDOG_RESET();
 346
 347             do
 348             {
 349               NORMALIZE
 350               range >>= 1;
 351
 352               {
 353                 UInt32 t;
 354                 code -= range;
 355                 t = (0 - ((UInt32)code >> 31)); /* (UInt32)((Int32)code >> 31) */
 356                 distance = (distance << 1) + (t + 1);
 357                 code += range & t;
 358               }
 359               /*
 360               distance <<= 1;
 361               if (code >= range)
 362               {
 363                 code -= range;
 364                 distance |= 1;
 365               }
 366               */
 367             }
 368             while (--numDirectBits != 0);
 369             prob = probs + Align;
 370             distance <<= kNumAlignBits;
 371             {
 372               unsigned i = 1;
 373               GET_BIT2(prob + i, i, ; , distance |= 1);
 374               GET_BIT2(prob + i, i, ; , distance |= 2);
 375               GET_BIT2(prob + i, i, ; , distance |= 4);
 376               GET_BIT2(prob + i, i, ; , distance |= 8);
 377             }
 378             if (distance == (UInt32)0xFFFFFFFF)
 379             {
 380               len += kMatchSpecLenStart;
 381               state -= kNumStates;
 382               break;
 383             }
 384           }
 385         }
 386         rep3 = rep2;
 387         rep2 = rep1;
 388         rep1 = rep0;
 389         rep0 = distance + 1;
 390         if (checkDicSize == 0)
 391         {
 392           if (distance >= processedPos)
 393             return SZ_ERROR_DATA;
 394         }
 395         else if (distance >= checkDicSize)
 396           return SZ_ERROR_DATA;
 397         state = (state < kNumStates + kNumLitStates) ? kNumLitStates : kNumLitStates + 3;
 398         /* state = kLiteralNextStates[state]; */
 399       }
 400
 401       len += kMatchMinLen;
 402
 403       if (limit == dicPos)
 404         return SZ_ERROR_DATA;
 405       {
 406         SizeT rem = limit - dicPos;
 407         unsigned curLen = ((rem < len) ? (unsigned)rem : len);
 408         SizeT pos = (dicPos - rep0) + ((dicPos < rep0) ? dicBufSize : 0);
 409
 410         processedPos += curLen;
 411
 412         len -= curLen;
 413         if (pos + curLen <= dicBufSize)
 414         {
 415           Byte *dest = dic + dicPos;
 416           ptrdiff_t src = (ptrdiff_t)pos - (ptrdiff_t)dicPos;
 417           const Byte *lim = dest + curLen;
 418           dicPos += curLen;
 419
 420           WATCHDOG_RESET();
 421
 422           do
 423             *(dest) = (Byte)*(dest + src);
 424           while (++dest != lim);
 425         }
 426         else
 427         {
 428
 429           WATCHDOG_RESET();
 430
 431           do
 432           {
 433             dic[dicPos++] = dic[pos];
 434             if (++pos == dicBufSize)
 435               pos = 0;
 436           }
 437           while (--curLen != 0);
 438         }
 439       }
 440     }
 441   }
 442   while (dicPos < limit && buf < bufLimit);
 443
 444   WATCHDOG_RESET();
 445
 446   NORMALIZE;
 447   p->buf = buf;
 448   p->range = range;
 449   p->code = code;
 450   p->remainLen = len;
 451   p->dicPos = dicPos;
 452   p->processedPos = processedPos;
 453   p->reps[0] = rep0;
 454   p->reps[1] = rep1;
 455   p->reps[2] = rep2;
 456   p->reps[3] = rep3;
 457   p->state = state;
 458
 459   return SZ_OK;
 460 }
 461
 462 static void MY_FAST_CALL LzmaDec_WriteRem(CLzmaDec *p, SizeT limit)
 463 {
 464   if (p->remainLen != 0 && p->remainLen < kMatchSpecLenStart)
 465   {
 466     Byte *dic = p->dic;
 467     SizeT dicPos = p->dicPos;
 468     SizeT dicBufSize = p->dicBufSize;
 469     unsigned len = p->remainLen;
 470     UInt32 rep0 = p->reps[0];
 471     if (limit - dicPos < len)
 472       len = (unsigned)(limit - dicPos);
 473
 474     if (p->checkDicSize == 0 && p->prop.dicSize - p->processedPos <= len)
 475       p->checkDicSize = p->prop.dicSize;
 476
 477     p->processedPos += len;
 478     p->remainLen -= len;
 479     while (len-- != 0)
 480     {
 481       dic[dicPos] = dic[(dicPos - rep0) + ((dicPos < rep0) ? dicBufSize : 0)];
 482       dicPos++;
 483     }
 484     p->dicPos = dicPos;
 485   }
 486 }
 487
 488 static int MY_FAST_CALL LzmaDec_DecodeReal2(CLzmaDec *p, SizeT limit, const Byte *bufLimit)
 489 {
 490   do
 491   {
 492     SizeT limit2 = limit;
 493     if (p->checkDicSize == 0)
 494     {
 495       UInt32 rem = p->prop.dicSize - p->processedPos;
 496       if (limit - p->dicPos > rem)
 497         limit2 = p->dicPos + rem;
 498     }
 499     RINOK(LzmaDec_DecodeReal(p, limit2, bufLimit));
 500     if (p->processedPos >= p->prop.dicSize)
 501       p->checkDicSize = p->prop.dicSize;
 502     LzmaDec_WriteRem(p, limit);
 503   }
 504   while (p->dicPos < limit && p->buf < bufLimit && p->remainLen < kMatchSpecLenStart);
 505
 506   if (p->remainLen > kMatchSpecLenStart)
 507   {
 508     p->remainLen = kMatchSpecLenStart;
 509   }
 510   return 0;
 511 }
 512
 513 typedef enum
 514 {
 515   DUMMY_ERROR, /* unexpected end of input stream */
 516   DUMMY_LIT,
 517   DUMMY_MATCH,
 518   DUMMY_REP
 519 } ELzmaDummy;
 520
 521 static ELzmaDummy LzmaDec_TryDummy(const CLzmaDec *p, const Byte *buf, SizeT inSize)
 522 {
 523   UInt32 range = p->range;
 524   UInt32 code = p->code;
 525   const Byte *bufLimit = buf + inSize;
 526   CLzmaProb *probs = p->probs;
 527   unsigned state = p->state;
 528   ELzmaDummy res;
 529
 530   {
 531     CLzmaProb *prob;
 532     UInt32 bound;
 533     unsigned ttt;
 534     unsigned posState = (p->processedPos) & ((1 << p->prop.pb) - 1);
 535
 536     prob = probs + IsMatch + (state << kNumPosBitsMax) + posState;
 537     IF_BIT_0_CHECK(prob)
 538     {
 539       UPDATE_0_CHECK
 540
 541       /* if (bufLimit - buf >= 7) return DUMMY_LIT; */
 542
 543       prob = probs + Literal;
 544       if (p->checkDicSize != 0 || p->processedPos != 0)
 545         prob += (LZMA_LIT_SIZE *
 546           ((((p->processedPos) & ((1 << (p->prop.lp)) - 1)) << p->prop.lc) +
 547           (p->dic[(p->dicPos == 0 ? p->dicBufSize : p->dicPos) - 1] >> (8 - p->prop.lc))));
 548
 549       if (state < kNumLitStates)
 550       {
 551         unsigned symbol = 1;
 552         do { GET_BIT_CHECK(prob + symbol, symbol) } while (symbol < 0x100);
 553       }
 554       else
 555       {
 556         unsigned matchByte = p->dic[p->dicPos - p->reps[0] +
 557             ((p->dicPos < p->reps[0]) ? p->dicBufSize : 0)];
 558         unsigned offs = 0x100;
 559         unsigned symbol = 1;
 560         do
 561         {
 562           unsigned bit;
 563           CLzmaProb *probLit;
 564           matchByte <<= 1;
 565           bit = (matchByte & offs);
 566           probLit = prob + offs + bit + symbol;
 567           GET_BIT2_CHECK(probLit, symbol, offs &= ~bit, offs &= bit)
 568         }
 569         while (symbol < 0x100);
 570       }
 571       res = DUMMY_LIT;
 572     }
 573     else
 574     {
 575       unsigned len;
 576       UPDATE_1_CHECK;
 577
 578       prob = probs + IsRep + state;
 579       IF_BIT_0_CHECK(prob)
 580       {
 581         UPDATE_0_CHECK;
 582         state = 0;
 583         prob = probs + LenCoder;
 584         res = DUMMY_MATCH;
 585       }
 586       else
 587       {
 588         UPDATE_1_CHECK;
 589         res = DUMMY_REP;
 590         prob = probs + IsRepG0 + state;
 591         IF_BIT_0_CHECK(prob)
 592         {
 593           UPDATE_0_CHECK;
 594           prob = probs + IsRep0Long + (state << kNumPosBitsMax) + posState;
 595           IF_BIT_0_CHECK(prob)
 596           {
 597             UPDATE_0_CHECK;
 598             NORMALIZE_CHECK;
 599             return DUMMY_REP;
 600           }
 601           else
 602           {
 603             UPDATE_1_CHECK;
 604           }
 605         }
 606         else
 607         {
 608           UPDATE_1_CHECK;
 609           prob = probs + IsRepG1 + state;
 610           IF_BIT_0_CHECK(prob)
 611           {
 612             UPDATE_0_CHECK;
 613           }
 614           else
 615           {
 616             UPDATE_1_CHECK;
 617             prob = probs + IsRepG2 + state;
 618             IF_BIT_0_CHECK(prob)
 619             {
 620               UPDATE_0_CHECK;
 621             }
 622             else
 623             {
 624               UPDATE_1_CHECK;
 625             }
 626           }
 627         }
 628         state = kNumStates;
 629         prob = probs + RepLenCoder;
 630       }
 631       {
 632         unsigned limit, offset;
 633         CLzmaProb *probLen = prob + LenChoice;
 634         IF_BIT_0_CHECK(probLen)
 635         {
 636           UPDATE_0_CHECK;
 637           probLen = prob + LenLow + (posState << kLenNumLowBits);
 638           offset = 0;
 639           limit = 1 << kLenNumLowBits;
 640         }
 641         else
 642         {
 643           UPDATE_1_CHECK;
 644           probLen = prob + LenChoice2;
 645           IF_BIT_0_CHECK(probLen)
 646           {
 647             UPDATE_0_CHECK;
 648             probLen = prob + LenMid + (posState << kLenNumMidBits);
 649             offset = kLenNumLowSymbols;
 650             limit = 1 << kLenNumMidBits;
 651           }
 652           else
 653           {
 654             UPDATE_1_CHECK;
 655             probLen = prob + LenHigh;
 656             offset = kLenNumLowSymbols + kLenNumMidSymbols;
 657             limit = 1 << kLenNumHighBits;
 658           }
 659         }
 660         TREE_DECODE_CHECK(probLen, limit, len);
 661         len += offset;
 662       }
 663
 664       if (state < 4)
 665       {
 666         unsigned posSlot;
 667         prob = probs + PosSlot +
 668             ((len < kNumLenToPosStates ? len : kNumLenToPosStates - 1) <<
 669             kNumPosSlotBits);
 670         TREE_DECODE_CHECK(prob, 1 << kNumPosSlotBits, posSlot);
 671         if (posSlot >= kStartPosModelIndex)
 672         {
 673           int numDirectBits = ((posSlot >> 1) - 1);
 674
 675           /* if (bufLimit - buf >= 8) return DUMMY_MATCH; */
 676
 677           if (posSlot < kEndPosModelIndex)
 678           {
 679             prob = probs + SpecPos + ((2 | (posSlot & 1)) << numDirectBits) - posSlot - 1;
 680           }
 681           else
 682           {
 683             numDirectBits -= kNumAlignBits;
 684             do
 685             {
 686               NORMALIZE_CHECK
 687               range >>= 1;
 688               code -= range & (((code - range) >> 31) - 1);
 689               /* if (code >= range) code -= range; */
 690             }
 691             while (--numDirectBits != 0);
 692             prob = probs + Align;
 693             numDirectBits = kNumAlignBits;
 694           }
 695           {
 696             unsigned i = 1;
 697             do
 698             {
 699               GET_BIT_CHECK(prob + i, i);
 700             }
 701             while (--numDirectBits != 0);
 702           }
 703         }
 704       }
 705     }
 706   }
 707   NORMALIZE_CHECK;
 708   return res;
 709 }
 710
 711
 712 static void LzmaDec_InitRc(CLzmaDec *p, const Byte *data)
 713 {
 714   p->code = ((UInt32)data[1] << 24) | ((UInt32)data[2] << 16) | ((UInt32)data[3] << 8) | ((UInt32)data[4]);
 715   p->range = 0xFFFFFFFF;
 716   p->needFlush = 0;
 717 }
 718
 719 void LzmaDec_InitDicAndState(CLzmaDec *p, Bool initDic, Bool initState)
 720 {
 721   p->needFlush = 1;
 722   p->remainLen = 0;
 723   p->tempBufSize = 0;
 724
 725   if (initDic)
 726   {
 727     p->processedPos = 0;
 728     p->checkDicSize = 0;
 729     p->needInitState = 1;
 730   }
 731   if (initState)
 732     p->needInitState = 1;
 733 }
 734
 735 void LzmaDec_Init(CLzmaDec *p)
 736 {
 737   p->dicPos = 0;
 738   LzmaDec_InitDicAndState(p, True, True);
 739 }
 740
 741 static void LzmaDec_InitStateReal(CLzmaDec *p)
 742 {
 743   UInt32 numProbs = Literal + ((UInt32)LZMA_LIT_SIZE << (p->prop.lc + p->prop.lp));
 744   UInt32 i;
 745   CLzmaProb *probs = p->probs;
 746   for (i = 0; i < numProbs; i++)
 747     probs[i] = kBitModelTotal >> 1;
 748   p->reps[0] = p->reps[1] = p->reps[2] = p->reps[3] = 1;
 749   p->state = 0;
 750   p->needInitState = 0;
 751 }
 752
 753 SRes LzmaDec_DecodeToDic(CLzmaDec *p, SizeT dicLimit, const Byte *src, SizeT *srcLen,
 754     ELzmaFinishMode finishMode, ELzmaStatus *status)
 755 {
 756   SizeT inSize = *srcLen;
 757   (*srcLen) = 0;
 758   LzmaDec_WriteRem(p, dicLimit);
 759
 760   *status = LZMA_STATUS_NOT_SPECIFIED;
 761
 762   while (p->remainLen != kMatchSpecLenStart)
 763   {
 764       int checkEndMarkNow;
 765
 766       if (p->needFlush != 0)
 767       {
 768         for (; inSize > 0 && p->tempBufSize < RC_INIT_SIZE; (*srcLen)++, inSize--)
 769           p->tempBuf[p->tempBufSize++] = *src++;
 770         if (p->tempBufSize < RC_INIT_SIZE)
 771         {
 772           *status = LZMA_STATUS_NEEDS_MORE_INPUT;
 773           return SZ_OK;
 774         }
 775         if (p->tempBuf[0] != 0)
 776           return SZ_ERROR_DATA;
 777
 778         LzmaDec_InitRc(p, p->tempBuf);
 779         p->tempBufSize = 0;
 780       }
 781
 782       checkEndMarkNow = 0;
 783       if (p->dicPos >= dicLimit)
 784       {
 785         if (p->remainLen == 0 && p->code == 0)
 786         {
 787           *status = LZMA_STATUS_MAYBE_FINISHED_WITHOUT_MARK;
 788           return SZ_OK;
 789         }
 790         if (finishMode == LZMA_FINISH_ANY)
 791         {
 792           *status = LZMA_STATUS_NOT_FINISHED;
 793           return SZ_OK;
 794         }
 795         if (p->remainLen != 0)
 796         {
 797           *status = LZMA_STATUS_NOT_FINISHED;
 798           return SZ_ERROR_DATA;
 799         }
 800         checkEndMarkNow = 1;
 801       }
 802
 803       if (p->needInitState)
 804         LzmaDec_InitStateReal(p);
 805
 806       if (p->tempBufSize == 0)
 807       {
 808         SizeT processed;
 809         const Byte *bufLimit;
 810         if (inSize < LZMA_REQUIRED_INPUT_MAX || checkEndMarkNow)
 811         {
 812           int dummyRes = LzmaDec_TryDummy(p, src, inSize);
 813           if (dummyRes == DUMMY_ERROR)
 814           {
 815             memcpy(p->tempBuf, src, inSize);
 816             p->tempBufSize = (unsigned)inSize;
 817             (*srcLen) += inSize;
 818             *status = LZMA_STATUS_NEEDS_MORE_INPUT;
 819             return SZ_OK;
 820           }
 821           if (checkEndMarkNow && dummyRes != DUMMY_MATCH)
 822           {
 823             *status = LZMA_STATUS_NOT_FINISHED;
 824             return SZ_ERROR_DATA;
 825           }
 826           bufLimit = src;
 827         }
 828         else
 829           bufLimit = src + inSize - LZMA_REQUIRED_INPUT_MAX;
 830         p->buf = src;
 831         if (LzmaDec_DecodeReal2(p, dicLimit, bufLimit) != 0)
 832           return SZ_ERROR_DATA;
 833         processed = (SizeT)(p->buf - src);
 834         (*srcLen) += processed;
 835         src += processed;
 836         inSize -= processed;
 837       }
 838       else
 839       {
 840         unsigned rem = p->tempBufSize, lookAhead = 0;
 841         while (rem < LZMA_REQUIRED_INPUT_MAX && lookAhead < inSize)
 842           p->tempBuf[rem++] = src[lookAhead++];
 843         p->tempBufSize = rem;
 844         if (rem < LZMA_REQUIRED_INPUT_MAX || checkEndMarkNow)
 845         {
 846           int dummyRes = LzmaDec_TryDummy(p, p->tempBuf, rem);
 847           if (dummyRes == DUMMY_ERROR)
 848           {
 849             (*srcLen) += lookAhead;
 850             *status = LZMA_STATUS_NEEDS_MORE_INPUT;
 851             return SZ_OK;
 852           }
 853           if (checkEndMarkNow && dummyRes != DUMMY_MATCH)
 854           {
 855             *status = LZMA_STATUS_NOT_FINISHED;
 856             return SZ_ERROR_DATA;
 857           }
 858         }
 859         p->buf = p->tempBuf;
 860         if (LzmaDec_DecodeReal2(p, dicLimit, p->buf) != 0)
 861           return SZ_ERROR_DATA;
 862         lookAhead -= (rem - (unsigned)(p->buf - p->tempBuf));
 863         (*srcLen) += lookAhead;
 864         src += lookAhead;
 865         inSize -= lookAhead;
 866         p->tempBufSize = 0;
 867       }
 868   }
 869   if (p->code == 0)
 870     *status = LZMA_STATUS_FINISHED_WITH_MARK;
 871   return (p->code == 0) ? SZ_OK : SZ_ERROR_DATA;
 872 }
 873
 874 SRes LzmaDec_DecodeToBuf(CLzmaDec *p, Byte *dest, SizeT *destLen, const Byte *src, SizeT *srcLen, ELzmaFinishMode finishMode, ELzmaStatus *status)
 875 {
 876   SizeT outSize = *destLen;
 877   SizeT inSize = *srcLen;
 878   *srcLen = *destLen = 0;
 879   for (;;)
 880   {
 881     SizeT inSizeCur = inSize, outSizeCur, dicPos;
 882     ELzmaFinishMode curFinishMode;
 883     SRes res;
 884     if (p->dicPos == p->dicBufSize)
 885       p->dicPos = 0;
 886     dicPos = p->dicPos;
 887     if (outSize > p->dicBufSize - dicPos)
 888     {
 889       outSizeCur = p->dicBufSize;
 890       curFinishMode = LZMA_FINISH_ANY;
 891     }
 892     else
 893     {
 894       outSizeCur = dicPos + outSize;
 895       curFinishMode = finishMode;
 896     }
 897
 898     res = LzmaDec_DecodeToDic(p, outSizeCur, src, &inSizeCur, curFinishMode, status);
 899     src += inSizeCur;
 900     inSize -= inSizeCur;
 901     *srcLen += inSizeCur;
 902     outSizeCur = p->dicPos - dicPos;
 903     memcpy(dest, p->dic + dicPos, outSizeCur);
 904     dest += outSizeCur;
 905     outSize -= outSizeCur;
 906     *destLen += outSizeCur;
 907     if (res != 0)
 908       return res;
 909     if (outSizeCur == 0 || outSize == 0)
 910       return SZ_OK;
 911   }
 912 }
 913
 914 void LzmaDec_FreeProbs(CLzmaDec *p, ISzAlloc *alloc)
 915 {
 916   alloc->Free(alloc, p->probs);
 917   p->probs = 0;
 918 }
 919
 920 static void LzmaDec_FreeDict(CLzmaDec *p, ISzAlloc *alloc)
 921 {
 922   alloc->Free(alloc, p->dic);
 923   p->dic = 0;
 924 }
 925
 926 void LzmaDec_Free(CLzmaDec *p, ISzAlloc *alloc)
 927 {
 928   LzmaDec_FreeProbs(p, alloc);
 929   LzmaDec_FreeDict(p, alloc);
 930 }
 931
 932 SRes LzmaProps_Decode(CLzmaProps *p, const Byte *data, unsigned size)
 933 {
 934   UInt32 dicSize;
 935   Byte d;
 936
 937   if (size < LZMA_PROPS_SIZE)
 938     return SZ_ERROR_UNSUPPORTED;
 939   else
 940     dicSize = data[1] | ((UInt32)data[2] << 8) | ((UInt32)data[3] << 16) | ((UInt32)data[4] << 24);
 941
 942   if (dicSize < LZMA_DIC_MIN)
 943     dicSize = LZMA_DIC_MIN;
 944   p->dicSize = dicSize;
 945
 946   d = data[0];
 947   if (d >= (9 * 5 * 5))
 948     return SZ_ERROR_UNSUPPORTED;
 949
 950   p->lc = d % 9;
 951   d /= 9;
 952   p->pb = d / 5;
 953   p->lp = d % 5;
 954
 955   return SZ_OK;
 956 }
 957
 958 static SRes LzmaDec_AllocateProbs2(CLzmaDec *p, const CLzmaProps *propNew, ISzAlloc *alloc)
 959 {
 960   UInt32 numProbs = LzmaProps_GetNumProbs(propNew);
 961   if (p->probs == 0 || numProbs != p->numProbs)
 962   {
 963     LzmaDec_FreeProbs(p, alloc);
 964     p->probs = (CLzmaProb *)alloc->Alloc(alloc, numProbs * sizeof(CLzmaProb));
 965     p->numProbs = numProbs;
 966     if (p->probs == 0)
 967       return SZ_ERROR_MEM;
 968   }
 969   return SZ_OK;
 970 }
 971
 972 SRes LzmaDec_AllocateProbs(CLzmaDec *p, const Byte *props, unsigned propsSize, ISzAlloc *alloc)
 973 {
 974   CLzmaProps propNew;
 975   RINOK(LzmaProps_Decode(&propNew, props, propsSize));
 976   RINOK(LzmaDec_AllocateProbs2(p, &propNew, alloc));
 977   p->prop = propNew;
 978   return SZ_OK;
 979 }
 980
 981 SRes LzmaDec_Allocate(CLzmaDec *p, const Byte *props, unsigned propsSize, ISzAlloc *alloc)
 982 {
 983   CLzmaProps propNew;
 984   SizeT dicBufSize;
 985   RINOK(LzmaProps_Decode(&propNew, props, propsSize));
 986   RINOK(LzmaDec_AllocateProbs2(p, &propNew, alloc));
 987   dicBufSize = propNew.dicSize;
 988   if (p->dic == 0 || dicBufSize != p->dicBufSize)
 989   {
 990     LzmaDec_FreeDict(p, alloc);
 991     p->dic = (Byte *)alloc->Alloc(alloc, dicBufSize);
 992     if (p->dic == 0)
 993     {
 994       LzmaDec_FreeProbs(p, alloc);
 995       return SZ_ERROR_MEM;
 996     }
 997   }
 998   p->dicBufSize = dicBufSize;
 999   p->prop = propNew;
1000   return SZ_OK;
1001 }
1002
1003 SRes LzmaDecode(Byte *dest, SizeT *destLen, const Byte *src, SizeT *srcLen,
1004     const Byte *propData, unsigned propSize, ELzmaFinishMode finishMode,
1005     ELzmaStatus *status, ISzAlloc *alloc)
1006 {
1007   CLzmaDec p;
1008   SRes res;
1009   SizeT inSize = *srcLen;
1010   SizeT outSize = *destLen;
1011   *srcLen = *destLen = 0;
1012   if (inSize < RC_INIT_SIZE)
1013     return SZ_ERROR_INPUT_EOF;
1014
1015   LzmaDec_Construct(&p);
1016   res = LzmaDec_AllocateProbs(&p, propData, propSize, alloc);
1017   if (res != 0)
1018     return res;
1019   p.dic = dest;
1020   p.dicBufSize = outSize;
1021
1022   LzmaDec_Init(&p);
1023
1024   *srcLen = inSize;
1025   res = LzmaDec_DecodeToDic(&p, outSize, src, srcLen, finishMode, status);
1026
1027   if (res == SZ_OK && *status == LZMA_STATUS_NEEDS_MORE_INPUT)
1028     res = SZ_ERROR_INPUT_EOF;
1029
1030   (*destLen) = p.dicPos;
1031   LzmaDec_FreeProbs(&p, alloc);
1032   return res;
1033 }