lib/legacy/zstd_v02.c

333 MEM_STATIC size_t   BIT_initDStream(BIT_DStream_t* bitD, const void* srcBuffer, size_t srcSize);
334 MEM_STATIC size_t   BIT_readBits(BIT_DStream_t* bitD, unsigned nbBits);
335 MEM_STATIC BIT_DStream_status BIT_reloadDStream(BIT_DStream_t* bitD);
336 MEM_STATIC unsigned BIT_endOfDStream(const BIT_DStream_t* bitD);
342 MEM_STATIC size_t BIT_readBitsFast(BIT_DStream_t* bitD, unsigned nbBits);
379 *  @bitD : a pointer to an already allocated BIT_DStream_t structure
384 MEM_STATIC size_t BIT_initDStream(BIT_DStream_t* bitD, const void* srcBuffer, size_t srcSize)
386     if (srcSize < 1) { memset(bitD, 0, sizeof(*bitD)); return ERROR(srcSize_wrong); }
391         bitD->start = (const char*)srcBuffer;
392         bitD->ptr   = (const char*)srcBuffer + srcSize - sizeof(size_t);
393         bitD->bitContainer = MEM_readLEST(bitD->ptr);
396         bitD->bitsConsumed = 8 - BIT_highbit32(contain32);
401         bitD->start = (const char*)srcBuffer;
402         bitD->ptr   = bitD->start;
403         bitD->bitContainer = *(const BYTE*)(bitD->start);
406             case 7: bitD->bitContainer += (size_t)(((const BYTE*)(bitD->start))[6]) << (sizeof(size_t)*8 - 16);
408             case 6: bitD->bitContainer += (size_t)(((const BYTE*)(bitD->start))[5]) << (sizeof(size_t)*8 - 24);
410             case 5: bitD->bitContainer += (size_t)(((const BYTE*)(bitD->start))[4]) << (sizeof(size_t)*8 - 32);
412             case 4: bitD->bitContainer += (size_t)(((const BYTE*)(bitD->start))[3]) << 24;
414             case 3: bitD->bitContainer += (size_t)(((const BYTE*)(bitD->start))[2]) << 16;
416             case 2: bitD->bitContainer += (size_t)(((const BYTE*)(bitD->start))[1]) <<  8;
422         bitD->bitsConsumed = 8 - BIT_highbit32(contain32);
423         bitD->bitsConsumed += (U32)(sizeof(size_t) - srcSize)*8;
429 MEM_STATIC size_t BIT_lookBits(BIT_DStream_t* bitD, U32 nbBits)
431     const U32 bitMask = sizeof(bitD->bitContainer)*8 - 1;
432     return ((bitD->bitContainer << (bitD->bitsConsumed & bitMask)) >> 1) >> ((bitMask-nbBits) & bitMask);
437 MEM_STATIC size_t BIT_lookBitsFast(BIT_DStream_t* bitD, U32 nbBits)
439     const U32 bitMask = sizeof(bitD->bitContainer)*8 - 1;
440     return (bitD->bitContainer << (bitD->bitsConsumed & bitMask)) >> (((bitMask+1)-nbBits) & bitMask);
443 MEM_STATIC void BIT_skipBits(BIT_DStream_t* bitD, U32 nbBits)
445     bitD->bitsConsumed += nbBits;
448 MEM_STATIC size_t BIT_readBits(BIT_DStream_t* bitD, U32 nbBits)
450     size_t value = BIT_lookBits(bitD, nbBits);
451     BIT_skipBits(bitD, nbBits);
457 MEM_STATIC size_t BIT_readBitsFast(BIT_DStream_t* bitD, U32 nbBits)
459     size_t value = BIT_lookBitsFast(bitD, nbBits);
460     BIT_skipBits(bitD, nbBits);
464 MEM_STATIC BIT_DStream_status BIT_reloadDStream(BIT_DStream_t* bitD)
466     if (bitD->bitsConsumed > (sizeof(bitD->bitContainer)*8))  /* should never happen */
469     if (bitD->ptr >= bitD->start + sizeof(bitD->bitContainer))
471         bitD->ptr -= bitD->bitsConsumed >> 3;
472         bitD->bitsConsumed &= 7;
473         bitD->bitContainer = MEM_readLEST(bitD->ptr);
476     if (bitD->ptr == bitD->start)
478         if (bitD->bitsConsumed < sizeof(bitD->bitContainer)*8) return BIT_DStream_endOfBuffer;
482         U32 nbBytes = bitD->bitsConsumed >> 3;
484         if (bitD->ptr - nbBytes < bitD->start)
486             nbBytes = (U32)(bitD->ptr - bitD->start);  /* ptr > start */
489         bitD->ptr -= nbBytes;
490         bitD->bitsConsumed -= nbBytes*8;
491         bitD->bitContainer = MEM_readLEST(bitD->ptr);   /* reminder : srcSize > sizeof(bitD) */
679 static void     FSE_initDState(FSE_DState_t* DStatePtr, BIT_DStream_t* bitD, const FSE_DTable* dt);
681 static unsigned char FSE_decodeSymbol(FSE_DState_t* DStatePtr, BIT_DStream_t* bitD);
689 static unsigned char FSE_decodeSymbolFast(FSE_DState_t* DStatePtr, BIT_DStream_t* bitD);
711 MEM_STATIC void FSE_initDState(FSE_DState_t* DStatePtr, BIT_DStream_t* bitD, const FSE_DTable* dt)
715     DStatePtr->state = BIT_readBits(bitD, DTableH.tableLog);
716     BIT_reloadDStream(bitD);
720 MEM_STATIC BYTE FSE_decodeSymbol(FSE_DState_t* DStatePtr, BIT_DStream_t* bitD)
725     size_t lowBits = BIT_readBits(bitD, nbBits);
731 MEM_STATIC BYTE FSE_decodeSymbolFast(FSE_DState_t* DStatePtr, BIT_DStream_t* bitD)
736     size_t lowBits = BIT_readBitsFast(bitD, nbBits);
1347     BIT_DStream_t bitD;
1353     errorCode = BIT_initDStream(&bitD, cSrc, cSrcSize);   /* replaced last arg by maxCompressed Size */
1356     FSE_initDState(&state1, &bitD, dt);
1357     FSE_initDState(&state2, &bitD, dt);
1359 #define FSE_GETSYMBOL(statePtr) fast ? FSE_decodeSymbolFast(statePtr, &bitD) : FSE_decodeSymbol(statePtr, &bitD)
1362     for ( ; (BIT_reloadDStream(&bitD)==BIT_DStream_unfinished) && (op<olimit) ; op+=4)
1366         if (FSE_MAX_TABLELOG*2+7 > sizeof(bitD.bitContainer)*8)    /* This test must be static */
1367             BIT_reloadDStream(&bitD);
1371         if (FSE_MAX_TABLELOG*4+7 > sizeof(bitD.bitContainer)*8)    /* This test must be static */
1372             { if (BIT_reloadDStream(&bitD) > BIT_DStream_unfinished) { op+=2; break; } }
1376         if (FSE_MAX_TABLELOG*2+7 > sizeof(bitD.bitContainer)*8)    /* This test must be static */
1377             BIT_reloadDStream(&bitD);
1383     /* note : BIT_reloadDStream(&bitD) >= FSE_DStream_partiallyFilled; Ends at exactly BIT_DStream_completed */
1386         if ( (BIT_reloadDStream(&bitD)>BIT_DStream_completed) || (op==omax) || (BIT_endOfDStream(&bitD) && (fast || FSE_endOfDState(&state1))) )
1391         if ( (BIT_reloadDStream(&bitD)>BIT_DStream_completed) || (op==omax) || (BIT_endOfDStream(&bitD) && (fast || FSE_endOfDState(&state2))) )
1398     if (BIT_endOfDStream(&bitD) && FSE_endOfDState(&state1) && FSE_endOfDState(&state2))