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      1 /* LzmaDec.c -- LZMA Decoder
      2 2015-01-01 : Igor Pavlov : Public domain */
      3 
      4 #include "Precomp.h"
      5 
      6 #include "LzmaDec.h"
      7 
      8 #include <string.h>
      9 
     10 #define kNumTopBits 24
     11 #define kTopValue ((UInt32)1 << kNumTopBits)
     12 
     13 #define kNumBitModelTotalBits 11
     14 #define kBitModelTotal (1 << kNumBitModelTotalBits)
     15 #define kNumMoveBits 5
     16 
     17 #define RC_INIT_SIZE 5
     18 
     19 #define NORMALIZE if (range < kTopValue) { range <<= 8; code = (code << 8) | (*buf++); }
     20 
     21 #define IF_BIT_0(p) ttt = *(p); NORMALIZE; bound = (range >> kNumBitModelTotalBits) * ttt; if (code < bound)
     22 #define UPDATE_0(p) range = bound; *(p) = (CLzmaProb)(ttt + ((kBitModelTotal - ttt) >> kNumMoveBits));
     23 #define UPDATE_1(p) range -= bound; code -= bound; *(p) = (CLzmaProb)(ttt - (ttt >> kNumMoveBits));
     24 #define GET_BIT2(p, i, A0, A1) IF_BIT_0(p) \
     25   { UPDATE_0(p); i = (i + i); A0; } else \
     26   { UPDATE_1(p); i = (i + i) + 1; A1; }
     27 #define GET_BIT(p, i) GET_BIT2(p, i, ; , ;)
     28 
     29 #define TREE_GET_BIT(probs, i) { GET_BIT((probs + i), i); }
     30 #define TREE_DECODE(probs, limit, i) \
     31   { i = 1; do { TREE_GET_BIT(probs, i); } while (i < limit); i -= limit; }
     32 
     33 /* #define _LZMA_SIZE_OPT */
     34 
     35 #ifdef _LZMA_SIZE_OPT
     36 #define TREE_6_DECODE(probs, i) TREE_DECODE(probs, (1 << 6), i)
     37 #else
     38 #define TREE_6_DECODE(probs, i) \
     39   { i = 1; \
     40   TREE_GET_BIT(probs, i); \
     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   i -= 0x40; }
     47 #endif
     48 
     49 #define NORMAL_LITER_DEC GET_BIT(prob + symbol, symbol)
     50 #define MATCHED_LITER_DEC \
     51   matchByte <<= 1; \
     52   bit = (matchByte & offs); \
     53   probLit = prob + offs + bit + symbol; \
     54   GET_BIT2(probLit, symbol, offs &= ~bit, offs &= bit)
     55 
     56 #define NORMALIZE_CHECK if (range < kTopValue) { if (buf >= bufLimit) return DUMMY_ERROR; range <<= 8; code = (code << 8) | (*buf++); }
     57 
     58 #define IF_BIT_0_CHECK(p) ttt = *(p); NORMALIZE_CHECK; bound = (range >> kNumBitModelTotalBits) * ttt; if (code < bound)
     59 #define UPDATE_0_CHECK range = bound;
     60 #define UPDATE_1_CHECK range -= bound; code -= bound;
     61 #define GET_BIT2_CHECK(p, i, A0, A1) IF_BIT_0_CHECK(p) \
     62   { UPDATE_0_CHECK; i = (i + i); A0; } else \
     63   { UPDATE_1_CHECK; i = (i + i) + 1; A1; }
     64 #define GET_BIT_CHECK(p, i) GET_BIT2_CHECK(p, i, ; , ;)
     65 #define TREE_DECODE_CHECK(probs, limit, i) \
     66   { i = 1; do { GET_BIT_CHECK(probs + i, i) } while (i < limit); i -= limit; }
     67 
     68 
     69 #define kNumPosBitsMax 4
     70 #define kNumPosStatesMax (1 << kNumPosBitsMax)
     71 
     72 #define kLenNumLowBits 3
     73 #define kLenNumLowSymbols (1 << kLenNumLowBits)
     74 #define kLenNumMidBits 3
     75 #define kLenNumMidSymbols (1 << kLenNumMidBits)
     76 #define kLenNumHighBits 8
     77 #define kLenNumHighSymbols (1 << kLenNumHighBits)
     78 
     79 #define LenChoice 0
     80 #define LenChoice2 (LenChoice + 1)
     81 #define LenLow (LenChoice2 + 1)
     82 #define LenMid (LenLow + (kNumPosStatesMax << kLenNumLowBits))
     83 #define LenHigh (LenMid + (kNumPosStatesMax << kLenNumMidBits))
     84 #define kNumLenProbs (LenHigh + kLenNumHighSymbols)
     85 
     86 
     87 #define kNumStates 12
     88 #define kNumLitStates 7
     89 
     90 #define kStartPosModelIndex 4
     91 #define kEndPosModelIndex 14
     92 #define kNumFullDistances (1 << (kEndPosModelIndex >> 1))
     93 
     94 #define kNumPosSlotBits 6
     95 #define kNumLenToPosStates 4
     96 
     97 #define kNumAlignBits 4
     98 #define kAlignTableSize (1 << kNumAlignBits)
     99 
    100 #define kMatchMinLen 2
    101 #define kMatchSpecLenStart (kMatchMinLen + kLenNumLowSymbols + kLenNumMidSymbols + kLenNumHighSymbols)
    102 
    103 #define IsMatch 0
    104 #define IsRep (IsMatch + (kNumStates << kNumPosBitsMax))
    105 #define IsRepG0 (IsRep + kNumStates)
    106 #define IsRepG1 (IsRepG0 + kNumStates)
    107 #define IsRepG2 (IsRepG1 + kNumStates)
    108 #define IsRep0Long (IsRepG2 + kNumStates)
    109 #define PosSlot (IsRep0Long + (kNumStates << kNumPosBitsMax))
    110 #define SpecPos (PosSlot + (kNumLenToPosStates << kNumPosSlotBits))
    111 #define Align (SpecPos + kNumFullDistances - kEndPosModelIndex)
    112 #define LenCoder (Align + kAlignTableSize)
    113 #define RepLenCoder (LenCoder + kNumLenProbs)
    114 #define Literal (RepLenCoder + kNumLenProbs)
    115 
    116 #define LZMA_BASE_SIZE 1846
    117 #define LZMA_LIT_SIZE 768
    118 
    119 #define LzmaProps_GetNumProbs(p) ((UInt32)LZMA_BASE_SIZE + (LZMA_LIT_SIZE << ((p)->lc + (p)->lp)))
    120 
    121 #if Literal != LZMA_BASE_SIZE
    122 StopCompilingDueBUG
    123 #endif
    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   do
    163   {
    164     CLzmaProb *prob;
    165     UInt32 bound;
    166     unsigned ttt;
    167     unsigned posState = processedPos & pbMask;
    168 
    169     prob = probs + IsMatch + (state << kNumPosBitsMax) + posState;
    170     IF_BIT_0(prob)
    171     {
    172       unsigned symbol;
    173       UPDATE_0(prob);
    174       prob = probs + Literal;
    175       if (checkDicSize != 0 || processedPos != 0)
    176         prob += (LZMA_LIT_SIZE * (((processedPos & lpMask) << lc) +
    177         (dic[(dicPos == 0 ? dicBufSize : dicPos) - 1] >> (8 - lc))));
    178 
    179       if (state < kNumLitStates)
    180       {
    181         state -= (state < 4) ? state : 3;
    182         symbol = 1;
    183         #ifdef _LZMA_SIZE_OPT
    184         do { NORMAL_LITER_DEC } while (symbol < 0x100);
    185         #else
    186         NORMAL_LITER_DEC
    187         NORMAL_LITER_DEC
    188         NORMAL_LITER_DEC
    189         NORMAL_LITER_DEC
    190         NORMAL_LITER_DEC
    191         NORMAL_LITER_DEC
    192         NORMAL_LITER_DEC
    193         NORMAL_LITER_DEC
    194         #endif
    195       }
    196       else
    197       {
    198         unsigned matchByte = dic[(dicPos - rep0) + ((dicPos < rep0) ? dicBufSize : 0)];
    199         unsigned offs = 0x100;
    200         state -= (state < 10) ? 3 : 6;
    201         symbol = 1;
    202         #ifdef _LZMA_SIZE_OPT
    203         do
    204         {
    205           unsigned bit;
    206           CLzmaProb *probLit;
    207           MATCHED_LITER_DEC
    208         }
    209         while (symbol < 0x100);
    210         #else
    211         {
    212           unsigned bit;
    213           CLzmaProb *probLit;
    214           MATCHED_LITER_DEC
    215           MATCHED_LITER_DEC
    216           MATCHED_LITER_DEC
    217           MATCHED_LITER_DEC
    218           MATCHED_LITER_DEC
    219           MATCHED_LITER_DEC
    220           MATCHED_LITER_DEC
    221           MATCHED_LITER_DEC
    222         }
    223         #endif
    224       }
    225       dic[dicPos++] = (Byte)symbol;
    226       processedPos++;
    227       continue;
    228     }
    229     else
    230     {
    231       UPDATE_1(prob);
    232       prob = probs + IsRep + state;
    233       IF_BIT_0(prob)
    234       {
    235         UPDATE_0(prob);
    236         state += kNumStates;
    237         prob = probs + LenCoder;
    238       }
    239       else
    240       {
    241         UPDATE_1(prob);
    242         if (checkDicSize == 0 && processedPos == 0)
    243           return SZ_ERROR_DATA;
    244         prob = probs + IsRepG0 + state;
    245         IF_BIT_0(prob)
    246         {
    247           UPDATE_0(prob);
    248           prob = probs + IsRep0Long + (state << kNumPosBitsMax) + posState;
    249           IF_BIT_0(prob)
    250           {
    251             UPDATE_0(prob);
    252             dic[dicPos] = dic[(dicPos - rep0) + ((dicPos < rep0) ? dicBufSize : 0)];
    253             dicPos++;
    254             processedPos++;
    255             state = state < kNumLitStates ? 9 : 11;
    256             continue;
    257           }
    258           UPDATE_1(prob);
    259         }
    260         else
    261         {
    262           UInt32 distance;
    263           UPDATE_1(prob);
    264           prob = probs + IsRepG1 + state;
    265           IF_BIT_0(prob)
    266           {
    267             UPDATE_0(prob);
    268             distance = rep1;
    269           }
    270           else
    271           {
    272             UPDATE_1(prob);
    273             prob = probs + IsRepG2 + state;
    274             IF_BIT_0(prob)
    275             {
    276               UPDATE_0(prob);
    277               distance = rep2;
    278             }
    279             else
    280             {
    281               UPDATE_1(prob);
    282               distance = rep3;
    283               rep3 = rep2;
    284             }
    285             rep2 = rep1;
    286           }
    287           rep1 = rep0;
    288           rep0 = distance;
    289         }
    290         state = state < kNumLitStates ? 8 : 11;
    291         prob = probs + RepLenCoder;
    292       }
    293       {
    294         unsigned limit, offset;
    295         CLzmaProb *probLen = prob + LenChoice;
    296         IF_BIT_0(probLen)
    297         {
    298           UPDATE_0(probLen);
    299           probLen = prob + LenLow + (posState << kLenNumLowBits);
    300           offset = 0;
    301           limit = (1 << kLenNumLowBits);
    302         }
    303         else
    304         {
    305           UPDATE_1(probLen);
    306           probLen = prob + LenChoice2;
    307           IF_BIT_0(probLen)
    308           {
    309             UPDATE_0(probLen);
    310             probLen = prob + LenMid + (posState << kLenNumMidBits);
    311             offset = kLenNumLowSymbols;
    312             limit = (1 << kLenNumMidBits);
    313           }
    314           else
    315           {
    316             UPDATE_1(probLen);
    317             probLen = prob + LenHigh;
    318             offset = kLenNumLowSymbols + kLenNumMidSymbols;
    319             limit = (1 << kLenNumHighBits);
    320           }
    321         }
    322         TREE_DECODE(probLen, limit, len);
    323         len += offset;
    324       }
    325 
    326       if (state >= kNumStates)
    327       {
    328         UInt32 distance;
    329         prob = probs + PosSlot +
    330             ((len < kNumLenToPosStates ? len : kNumLenToPosStates - 1) << kNumPosSlotBits);
    331         TREE_6_DECODE(prob, distance);
    332         if (distance >= kStartPosModelIndex)
    333         {
    334           unsigned posSlot = (unsigned)distance;
    335           int numDirectBits = (int)(((distance >> 1) - 1));
    336           distance = (2 | (distance & 1));
    337           if (posSlot < kEndPosModelIndex)
    338           {
    339             distance <<= numDirectBits;
    340             prob = probs + SpecPos + distance - posSlot - 1;
    341             {
    342               UInt32 mask = 1;
    343               unsigned i = 1;
    344               do
    345               {
    346                 GET_BIT2(prob + i, i, ; , distance |= mask);
    347                 mask <<= 1;
    348               }
    349               while (--numDirectBits != 0);
    350             }
    351           }
    352           else
    353           {
    354             numDirectBits -= kNumAlignBits;
    355             do
    356             {
    357               NORMALIZE
    358               range >>= 1;
    359 
    360               {
    361                 UInt32 t;
    362                 code -= range;
    363                 t = (0 - ((UInt32)code >> 31)); /* (UInt32)((Int32)code >> 31) */
    364                 distance = (distance << 1) + (t + 1);
    365                 code += range & t;
    366               }
    367               /*
    368               distance <<= 1;
    369               if (code >= range)
    370               {
    371                 code -= range;
    372                 distance |= 1;
    373               }
    374               */
    375             }
    376             while (--numDirectBits != 0);
    377             prob = probs + Align;
    378             distance <<= kNumAlignBits;
    379             {
    380               unsigned i = 1;
    381               GET_BIT2(prob + i, i, ; , distance |= 1);
    382               GET_BIT2(prob + i, i, ; , distance |= 2);
    383               GET_BIT2(prob + i, i, ; , distance |= 4);
    384               GET_BIT2(prob + i, i, ; , distance |= 8);
    385             }
    386             if (distance == (UInt32)0xFFFFFFFF)
    387             {
    388               len += kMatchSpecLenStart;
    389               state -= kNumStates;
    390               break;
    391             }
    392           }
    393         }
    394         rep3 = rep2;
    395         rep2 = rep1;
    396         rep1 = rep0;
    397         rep0 = distance + 1;
    398         if (checkDicSize == 0)
    399         {
    400           if (distance >= processedPos)
    401             return SZ_ERROR_DATA;
    402         }
    403         else if (distance >= checkDicSize)
    404           return SZ_ERROR_DATA;
    405         state = (state < kNumStates + kNumLitStates) ? kNumLitStates : kNumLitStates + 3;
    406       }
    407 
    408       len += kMatchMinLen;
    409 
    410       if (limit == dicPos)
    411         return SZ_ERROR_DATA;
    412       {
    413         SizeT rem = limit - dicPos;
    414         unsigned curLen = ((rem < len) ? (unsigned)rem : len);
    415         SizeT pos = (dicPos - rep0) + ((dicPos < rep0) ? dicBufSize : 0);
    416 
    417         processedPos += curLen;
    418 
    419         len -= curLen;
    420         if (pos + curLen <= dicBufSize)
    421         {
    422           Byte *dest = dic + dicPos;
    423           ptrdiff_t src = (ptrdiff_t)pos - (ptrdiff_t)dicPos;
    424           const Byte *lim = dest + curLen;
    425           dicPos += curLen;
    426           do
    427             *(dest) = (Byte)*(dest + src);
    428           while (++dest != lim);
    429         }
    430         else
    431         {
    432           do
    433           {
    434             dic[dicPos++] = dic[pos];
    435             if (++pos == dicBufSize)
    436               pos = 0;
    437           }
    438           while (--curLen != 0);
    439         }
    440       }
    441     }
    442   }
    443   while (dicPos < limit && buf < bufLimit);
    444   NORMALIZE;
    445   p->buf = buf;
    446   p->range = range;
    447   p->code = code;
    448   p->remainLen = len;
    449   p->dicPos = dicPos;
    450   p->processedPos = processedPos;
    451   p->reps[0] = rep0;
    452   p->reps[1] = rep1;
    453   p->reps[2] = rep2;
    454   p->reps[3] = rep3;
    455   p->state = state;
    456 
    457   return SZ_OK;
    458 }
    459 
    460 static void MY_FAST_CALL LzmaDec_WriteRem(CLzmaDec *p, SizeT limit)
    461 {
    462   if (p->remainLen != 0 && p->remainLen < kMatchSpecLenStart)
    463   {
    464     Byte *dic = p->dic;
    465     SizeT dicPos = p->dicPos;
    466     SizeT dicBufSize = p->dicBufSize;
    467     unsigned len = p->remainLen;
    468     UInt32 rep0 = p->reps[0];
    469     if (limit - dicPos < len)
    470       len = (unsigned)(limit - dicPos);
    471 
    472     if (p->checkDicSize == 0 && p->prop.dicSize - p->processedPos <= len)
    473       p->checkDicSize = p->prop.dicSize;
    474 
    475     p->processedPos += len;
    476     p->remainLen -= len;
    477     while (len != 0)
    478     {
    479       len--;
    480       dic[dicPos] = dic[(dicPos - rep0) + ((dicPos < rep0) ? dicBufSize : 0)];
    481       dicPos++;
    482     }
    483     p->dicPos = dicPos;
    484   }
    485 }
    486 
    487 static int MY_FAST_CALL LzmaDec_DecodeReal2(CLzmaDec *p, SizeT limit, const Byte *bufLimit)
    488 {
    489   do
    490   {
    491     SizeT limit2 = limit;
    492     if (p->checkDicSize == 0)
    493     {
    494       UInt32 rem = p->prop.dicSize - p->processedPos;
    495       if (limit - p->dicPos > rem)
    496         limit2 = p->dicPos + rem;
    497     }
    498     RINOK(LzmaDec_DecodeReal(p, limit2, bufLimit));
    499     if (p->processedPos >= p->prop.dicSize)
    500       p->checkDicSize = p->prop.dicSize;
    501     LzmaDec_WriteRem(p, limit);
    502   }
    503   while (p->dicPos < limit && p->buf < bufLimit && p->remainLen < kMatchSpecLenStart);
    504 
    505   if (p->remainLen > kMatchSpecLenStart)
    506   {
    507     p->remainLen = kMatchSpecLenStart;
    508   }
    509   return 0;
    510 }
    511 
    512 typedef enum
    513 {
    514   DUMMY_ERROR, /* unexpected end of input stream */
    515   DUMMY_LIT,
    516   DUMMY_MATCH,
    517   DUMMY_REP
    518 } ELzmaDummy;
    519 
    520 static ELzmaDummy LzmaDec_TryDummy(const CLzmaDec *p, const Byte *buf, SizeT inSize)
    521 {
    522   UInt32 range = p->range;
    523   UInt32 code = p->code;
    524   const Byte *bufLimit = buf + inSize;
    525   CLzmaProb *probs = p->probs;
    526   unsigned state = p->state;
    527   ELzmaDummy res;
    528 
    529   {
    530     CLzmaProb *prob;
    531     UInt32 bound;
    532     unsigned ttt;
    533     unsigned posState = (p->processedPos) & ((1 << p->prop.pb) - 1);
    534 
    535     prob = probs + IsMatch + (state << kNumPosBitsMax) + posState;
    536     IF_BIT_0_CHECK(prob)
    537     {
    538       UPDATE_0_CHECK
    539 
    540       /* if (bufLimit - buf >= 7) return DUMMY_LIT; */
    541 
    542       prob = probs + Literal;
    543       if (p->checkDicSize != 0 || p->processedPos != 0)
    544         prob += (LZMA_LIT_SIZE *
    545           ((((p->processedPos) & ((1 << (p->prop.lp)) - 1)) << p->prop.lc) +
    546           (p->dic[(p->dicPos == 0 ? p->dicBufSize : p->dicPos) - 1] >> (8 - p->prop.lc))));
    547 
    548       if (state < kNumLitStates)
    549       {
    550         unsigned symbol = 1;
    551         do { GET_BIT_CHECK(prob + symbol, symbol) } while (symbol < 0x100);
    552       }
    553       else
    554       {
    555         unsigned matchByte = p->dic[p->dicPos - p->reps[0] +
    556             ((p->dicPos < p->reps[0]) ? p->dicBufSize : 0)];
    557         unsigned offs = 0x100;
    558         unsigned symbol = 1;
    559         do
    560         {
    561           unsigned bit;
    562           CLzmaProb *probLit;
    563           matchByte <<= 1;
    564           bit = (matchByte & offs);
    565           probLit = prob + offs + bit + symbol;
    566           GET_BIT2_CHECK(probLit, symbol, offs &= ~bit, offs &= bit)
    567         }
    568         while (symbol < 0x100);
    569       }
    570       res = DUMMY_LIT;
    571     }
    572     else
    573     {
    574       unsigned len;
    575       UPDATE_1_CHECK;
    576 
    577       prob = probs + IsRep + state;
    578       IF_BIT_0_CHECK(prob)
    579       {
    580         UPDATE_0_CHECK;
    581         state = 0;
    582         prob = probs + LenCoder;
    583         res = DUMMY_MATCH;
    584       }
    585       else
    586       {
    587         UPDATE_1_CHECK;
    588         res = DUMMY_REP;
    589         prob = probs + IsRepG0 + state;
    590         IF_BIT_0_CHECK(prob)
    591         {
    592           UPDATE_0_CHECK;
    593           prob = probs + IsRep0Long + (state << kNumPosBitsMax) + posState;
    594           IF_BIT_0_CHECK(prob)
    595           {
    596             UPDATE_0_CHECK;
    597             NORMALIZE_CHECK;
    598             return DUMMY_REP;
    599           }
    600           else
    601           {
    602             UPDATE_1_CHECK;
    603           }
    604         }
    605         else
    606         {
    607           UPDATE_1_CHECK;
    608           prob = probs + IsRepG1 + state;
    609           IF_BIT_0_CHECK(prob)
    610           {
    611             UPDATE_0_CHECK;
    612           }
    613           else
    614           {
    615             UPDATE_1_CHECK;
    616             prob = probs + IsRepG2 + state;
    617             IF_BIT_0_CHECK(prob)
    618             {
    619               UPDATE_0_CHECK;
    620             }
    621             else
    622             {
    623               UPDATE_1_CHECK;
    624             }
    625           }
    626         }
    627         state = kNumStates;
    628         prob = probs + RepLenCoder;
    629       }
    630       {
    631         unsigned limit, offset;
    632         CLzmaProb *probLen = prob + LenChoice;
    633         IF_BIT_0_CHECK(probLen)
    634         {
    635           UPDATE_0_CHECK;
    636           probLen = prob + LenLow + (posState << kLenNumLowBits);
    637           offset = 0;
    638           limit = 1 << kLenNumLowBits;
    639         }
    640         else
    641         {
    642           UPDATE_1_CHECK;
    643           probLen = prob + LenChoice2;
    644           IF_BIT_0_CHECK(probLen)
    645           {
    646             UPDATE_0_CHECK;
    647             probLen = prob + LenMid + (posState << kLenNumMidBits);
    648             offset = kLenNumLowSymbols;
    649             limit = 1 << kLenNumMidBits;
    650           }
    651           else
    652           {
    653             UPDATE_1_CHECK;
    654             probLen = prob + LenHigh;
    655             offset = kLenNumLowSymbols + kLenNumMidSymbols;
    656             limit = 1 << kLenNumHighBits;
    657           }
    658         }
    659         TREE_DECODE_CHECK(probLen, limit, len);
    660         len += offset;
    661       }
    662 
    663       if (state < 4)
    664       {
    665         unsigned posSlot;
    666         prob = probs + PosSlot +
    667             ((len < kNumLenToPosStates ? len : kNumLenToPosStates - 1) <<
    668             kNumPosSlotBits);
    669         TREE_DECODE_CHECK(prob, 1 << kNumPosSlotBits, posSlot);
    670         if (posSlot >= kStartPosModelIndex)
    671         {
    672           int numDirectBits = ((posSlot >> 1) - 1);
    673 
    674           /* if (bufLimit - buf >= 8) return DUMMY_MATCH; */
    675 
    676           if (posSlot < kEndPosModelIndex)
    677           {
    678             prob = probs + SpecPos + ((2 | (posSlot & 1)) << numDirectBits) - posSlot - 1;
    679           }
    680           else
    681           {
    682             numDirectBits -= kNumAlignBits;
    683             do
    684             {
    685               NORMALIZE_CHECK
    686               range >>= 1;
    687               code -= range & (((code - range) >> 31) - 1);
    688               /* if (code >= range) code -= range; */
    689             }
    690             while (--numDirectBits != 0);
    691             prob = probs + Align;
    692             numDirectBits = kNumAlignBits;
    693           }
    694           {
    695             unsigned i = 1;
    696             do
    697             {
    698               GET_BIT_CHECK(prob + i, i);
    699             }
    700             while (--numDirectBits != 0);
    701           }
    702         }
    703       }
    704     }
    705   }
    706   NORMALIZE_CHECK;
    707   return res;
    708 }
    709 
    710 
    711 static void LzmaDec_InitRc(CLzmaDec *p, const Byte *data)
    712 {
    713   p->code = ((UInt32)data[1] << 24) | ((UInt32)data[2] << 16) | ((UInt32)data[3] << 8) | ((UInt32)data[4]);
    714   p->range = 0xFFFFFFFF;
    715   p->needFlush = 0;
    716 }
    717 
    718 void LzmaDec_InitDicAndState(CLzmaDec *p, Bool initDic, Bool initState)
    719 {
    720   p->needFlush = 1;
    721   p->remainLen = 0;
    722   p->tempBufSize = 0;
    723 
    724   if (initDic)
    725   {
    726     p->processedPos = 0;
    727     p->checkDicSize = 0;
    728     p->needInitState = 1;
    729   }
    730   if (initState)
    731     p->needInitState = 1;
    732 }
    733 
    734 void LzmaDec_Init(CLzmaDec *p)
    735 {
    736   p->dicPos = 0;
    737   LzmaDec_InitDicAndState(p, True, True);
    738 }
    739 
    740 static void LzmaDec_InitStateReal(CLzmaDec *p)
    741 {
    742   UInt32 numProbs = Literal + ((UInt32)LZMA_LIT_SIZE << (p->prop.lc + p->prop.lp));
    743   UInt32 i;
    744   CLzmaProb *probs = p->probs;
    745   for (i = 0; i < numProbs; i++)
    746     probs[i] = kBitModelTotal >> 1;
    747   p->reps[0] = p->reps[1] = p->reps[2] = p->reps[3] = 1;
    748   p->state = 0;
    749   p->needInitState = 0;
    750 }
    751 
    752 SRes LzmaDec_DecodeToDic(CLzmaDec *p, SizeT dicLimit, const Byte *src, SizeT *srcLen,
    753     ELzmaFinishMode finishMode, ELzmaStatus *status)
    754 {
    755   SizeT inSize = *srcLen;
    756   (*srcLen) = 0;
    757   LzmaDec_WriteRem(p, dicLimit);
    758 
    759   *status = LZMA_STATUS_NOT_SPECIFIED;
    760 
    761   while (p->remainLen != kMatchSpecLenStart)
    762   {
    763       int checkEndMarkNow;
    764 
    765       if (p->needFlush != 0)
    766       {
    767         for (; inSize > 0 && p->tempBufSize < RC_INIT_SIZE; (*srcLen)++, inSize--)
    768           p->tempBuf[p->tempBufSize++] = *src++;
    769         if (p->tempBufSize < RC_INIT_SIZE)
    770         {
    771           *status = LZMA_STATUS_NEEDS_MORE_INPUT;
    772           return SZ_OK;
    773         }
    774         if (p->tempBuf[0] != 0)
    775           return SZ_ERROR_DATA;
    776 
    777         LzmaDec_InitRc(p, p->tempBuf);
    778         p->tempBufSize = 0;
    779       }
    780 
    781       checkEndMarkNow = 0;
    782       if (p->dicPos >= dicLimit)
    783       {
    784         if (p->remainLen == 0 && p->code == 0)
    785         {
    786           *status = LZMA_STATUS_MAYBE_FINISHED_WITHOUT_MARK;
    787           return SZ_OK;
    788         }
    789         if (finishMode == LZMA_FINISH_ANY)
    790         {
    791           *status = LZMA_STATUS_NOT_FINISHED;
    792           return SZ_OK;
    793         }
    794         if (p->remainLen != 0)
    795         {
    796           *status = LZMA_STATUS_NOT_FINISHED;
    797           return SZ_ERROR_DATA;
    798         }
    799         checkEndMarkNow = 1;
    800       }
    801 
    802       if (p->needInitState)
    803         LzmaDec_InitStateReal(p);
    804 
    805       if (p->tempBufSize == 0)
    806       {
    807         SizeT processed;
    808         const Byte *bufLimit;
    809         if (inSize < LZMA_REQUIRED_INPUT_MAX || checkEndMarkNow)
    810         {
    811           int dummyRes = LzmaDec_TryDummy(p, src, inSize);
    812           if (dummyRes == DUMMY_ERROR)
    813           {
    814             memcpy(p->tempBuf, src, inSize);
    815             p->tempBufSize = (unsigned)inSize;
    816             (*srcLen) += inSize;
    817             *status = LZMA_STATUS_NEEDS_MORE_INPUT;
    818             return SZ_OK;
    819           }
    820           if (checkEndMarkNow && dummyRes != DUMMY_MATCH)
    821           {
    822             *status = LZMA_STATUS_NOT_FINISHED;
    823             return SZ_ERROR_DATA;
    824           }
    825           bufLimit = src;
    826         }
    827         else
    828           bufLimit = src + inSize - LZMA_REQUIRED_INPUT_MAX;
    829         p->buf = src;
    830         if (LzmaDec_DecodeReal2(p, dicLimit, bufLimit) != 0)
    831           return SZ_ERROR_DATA;
    832         processed = (SizeT)(p->buf - src);
    833         (*srcLen) += processed;
    834         src += processed;
    835         inSize -= processed;
    836       }
    837       else
    838       {
    839         unsigned rem = p->tempBufSize, lookAhead = 0;
    840         while (rem < LZMA_REQUIRED_INPUT_MAX && lookAhead < inSize)
    841           p->tempBuf[rem++] = src[lookAhead++];
    842         p->tempBufSize = rem;
    843         if (rem < LZMA_REQUIRED_INPUT_MAX || checkEndMarkNow)
    844         {
    845           int dummyRes = LzmaDec_TryDummy(p, p->tempBuf, rem);
    846           if (dummyRes == DUMMY_ERROR)
    847           {
    848             (*srcLen) += lookAhead;
    849             *status = LZMA_STATUS_NEEDS_MORE_INPUT;
    850             return SZ_OK;
    851           }
    852           if (checkEndMarkNow && dummyRes != DUMMY_MATCH)
    853           {
    854             *status = LZMA_STATUS_NOT_FINISHED;
    855             return SZ_ERROR_DATA;
    856           }
    857         }
    858         p->buf = p->tempBuf;
    859         if (LzmaDec_DecodeReal2(p, dicLimit, p->buf) != 0)
    860           return SZ_ERROR_DATA;
    861         lookAhead -= (rem - (unsigned)(p->buf - p->tempBuf));
    862         (*srcLen) += lookAhead;
    863         src += lookAhead;
    864         inSize -= lookAhead;
    865         p->tempBufSize = 0;
    866       }
    867   }
    868   if (p->code == 0)
    869     *status = LZMA_STATUS_FINISHED_WITH_MARK;
    870   return (p->code == 0) ? SZ_OK : SZ_ERROR_DATA;
    871 }
    872 
    873 SRes LzmaDec_DecodeToBuf(CLzmaDec *p, Byte *dest, SizeT *destLen, const Byte *src, SizeT *srcLen, ELzmaFinishMode finishMode, ELzmaStatus *status)
    874 {
    875   SizeT outSize = *destLen;
    876   SizeT inSize = *srcLen;
    877   *srcLen = *destLen = 0;
    878   for (;;)
    879   {
    880     SizeT inSizeCur = inSize, outSizeCur, dicPos;
    881     ELzmaFinishMode curFinishMode;
    882     SRes res;
    883     if (p->dicPos == p->dicBufSize)
    884       p->dicPos = 0;
    885     dicPos = p->dicPos;
    886     if (outSize > p->dicBufSize - dicPos)
    887     {
    888       outSizeCur = p->dicBufSize;
    889       curFinishMode = LZMA_FINISH_ANY;
    890     }
    891     else
    892     {
    893       outSizeCur = dicPos + outSize;
    894       curFinishMode = finishMode;
    895     }
    896 
    897     res = LzmaDec_DecodeToDic(p, outSizeCur, src, &inSizeCur, curFinishMode, status);
    898     src += inSizeCur;
    899     inSize -= inSizeCur;
    900     *srcLen += inSizeCur;
    901     outSizeCur = p->dicPos - dicPos;
    902     memcpy(dest, p->dic + dicPos, outSizeCur);
    903     dest += outSizeCur;
    904     outSize -= outSizeCur;
    905     *destLen += outSizeCur;
    906     if (res != 0)
    907       return res;
    908     if (outSizeCur == 0 || outSize == 0)
    909       return SZ_OK;
    910   }
    911 }
    912 
    913 void LzmaDec_FreeProbs(CLzmaDec *p, ISzAlloc *alloc)
    914 {
    915   alloc->Free(alloc, p->probs);
    916   p->probs = 0;
    917 }
    918 
    919 static void LzmaDec_FreeDict(CLzmaDec *p, ISzAlloc *alloc)
    920 {
    921   alloc->Free(alloc, p->dic);
    922   p->dic = 0;
    923 }
    924 
    925 void LzmaDec_Free(CLzmaDec *p, ISzAlloc *alloc)
    926 {
    927   LzmaDec_FreeProbs(p, alloc);
    928   LzmaDec_FreeDict(p, alloc);
    929 }
    930 
    931 SRes LzmaProps_Decode(CLzmaProps *p, const Byte *data, unsigned size)
    932 {
    933   UInt32 dicSize;
    934   Byte d;
    935 
    936   if (size < LZMA_PROPS_SIZE)
    937     return SZ_ERROR_UNSUPPORTED;
    938   else
    939     dicSize = data[1] | ((UInt32)data[2] << 8) | ((UInt32)data[3] << 16) | ((UInt32)data[4] << 24);
    940 
    941   if (dicSize < LZMA_DIC_MIN)
    942     dicSize = LZMA_DIC_MIN;
    943   p->dicSize = dicSize;
    944 
    945   d = data[0];
    946   if (d >= (9 * 5 * 5))
    947     return SZ_ERROR_UNSUPPORTED;
    948 
    949   p->lc = d % 9;
    950   d /= 9;
    951   p->pb = d / 5;
    952   p->lp = d % 5;
    953 
    954   return SZ_OK;
    955 }
    956 
    957 static SRes LzmaDec_AllocateProbs2(CLzmaDec *p, const CLzmaProps *propNew, ISzAlloc *alloc)
    958 {
    959   UInt32 numProbs = LzmaProps_GetNumProbs(propNew);
    960   if (p->probs == 0 || numProbs != p->numProbs)
    961   {
    962     LzmaDec_FreeProbs(p, alloc);
    963     p->probs = (CLzmaProb *)alloc->Alloc(alloc, numProbs * sizeof(CLzmaProb));
    964     p->numProbs = numProbs;
    965     if (p->probs == 0)
    966       return SZ_ERROR_MEM;
    967   }
    968   return SZ_OK;
    969 }
    970 
    971 SRes LzmaDec_AllocateProbs(CLzmaDec *p, const Byte *props, unsigned propsSize, ISzAlloc *alloc)
    972 {
    973   CLzmaProps propNew;
    974   RINOK(LzmaProps_Decode(&propNew, props, propsSize));
    975   RINOK(LzmaDec_AllocateProbs2(p, &propNew, alloc));
    976   p->prop = propNew;
    977   return SZ_OK;
    978 }
    979 
    980 SRes LzmaDec_Allocate(CLzmaDec *p, const Byte *props, unsigned propsSize, ISzAlloc *alloc)
    981 {
    982   CLzmaProps propNew;
    983   SizeT dicBufSize;
    984   RINOK(LzmaProps_Decode(&propNew, props, propsSize));
    985   RINOK(LzmaDec_AllocateProbs2(p, &propNew, alloc));
    986   dicBufSize = propNew.dicSize;
    987   if (p->dic == 0 || dicBufSize != p->dicBufSize)
    988   {
    989     LzmaDec_FreeDict(p, alloc);
    990     p->dic = (Byte *)alloc->Alloc(alloc, dicBufSize);
    991     if (p->dic == 0)
    992     {
    993       LzmaDec_FreeProbs(p, alloc);
    994       return SZ_ERROR_MEM;
    995     }
    996   }
    997   p->dicBufSize = dicBufSize;
    998   p->prop = propNew;
    999   return SZ_OK;
   1000 }
   1001 
   1002 SRes LzmaDecode(Byte *dest, SizeT *destLen, const Byte *src, SizeT *srcLen,
   1003     const Byte *propData, unsigned propSize, ELzmaFinishMode finishMode,
   1004     ELzmaStatus *status, ISzAlloc *alloc)
   1005 {
   1006   CLzmaDec p;
   1007   SRes res;
   1008   SizeT outSize = *destLen, inSize = *srcLen;
   1009   *destLen = *srcLen = 0;
   1010   *status = LZMA_STATUS_NOT_SPECIFIED;
   1011   if (inSize < RC_INIT_SIZE)
   1012     return SZ_ERROR_INPUT_EOF;
   1013   LzmaDec_Construct(&p);
   1014   RINOK(LzmaDec_AllocateProbs(&p, propData, propSize, alloc));
   1015   p.dic = dest;
   1016   p.dicBufSize = outSize;
   1017   LzmaDec_Init(&p);
   1018   *srcLen = inSize;
   1019   res = LzmaDec_DecodeToDic(&p, outSize, src, srcLen, finishMode, status);
   1020   *destLen = p.dicPos;
   1021   if (res == SZ_OK && *status == LZMA_STATUS_NEEDS_MORE_INPUT)
   1022     res = SZ_ERROR_INPUT_EOF;
   1023   LzmaDec_FreeProbs(&p, alloc);
   1024   return res;
   1025 }
   1026