ddidderr/zstd-rs
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Implemented default coding table for lengths and offset

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This commit is contained in:
Yann Collet
2016-04-07 15:24:29 +02:00
parent 79459da14b
commit 485371600a
4 changed files with 31 additions and 56 deletions
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lib/zstd_decompress.c
+4 -32
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@@ -500,34 +500,6 @@ size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx,
@return : nb bytes read from src,
or an error code if it fails, testable with ZSTD_isError()
*/
FORCE_INLINE size_t ZSTD_buildSeqTableOff(FSE_DTable* DTable, U32 type, U32 rawBits, U32 maxLog,
const void* src, size_t srcSize)
{
U32 max = (1<<rawBits)-1;
switch(type)
{
case FSE_ENCODING_RLE :
if (!srcSize) return ERROR(srcSize_wrong);
FSE_buildDTable_rle(DTable, (*(const BYTE*)src) & max); /* if *src > max, data is corrupted */
return 1;
case FSE_ENCODING_RAW :
FSE_buildDTable_raw(DTable, rawBits);
return 0;
case FSE_ENCODING_STATIC:
return 0;
default : /* impossible */
case FSE_ENCODING_DYNAMIC :
{ U32 tableLog;
S16 norm[MaxSeq+1];
size_t const headerSize = FSE_readNCount(norm, &max, &tableLog, src, srcSize);
if (FSE_isError(headerSize)) return ERROR(corruption_detected);
if (tableLog > maxLog) return ERROR(corruption_detected);
FSE_buildDTable(DTable, norm, max, tableLog);
return headerSize;
} }
}
FORCE_INLINE size_t ZSTD_buildSeqTable(FSE_DTable* DTable, U32 type, U32 max, U32 maxLog,
const void* src, size_t srcSize,
const S16* defaultNorm, U32 defaultLog)
@@ -594,7 +566,7 @@ size_t ZSTD_decodeSeqHeaders(int* nbSeqPtr,
if (ZSTD_isError(bhSize)) return ERROR(corruption_detected);
ip += bhSize;
}
{ size_t const bhSize = ZSTD_buildSeqTableOff(DTableOffb, Offtype, Offbits, OffFSELog, ip, iend-ip);
{ size_t const bhSize = ZSTD_buildSeqTable(DTableOffb, Offtype, MaxOff, OffFSELog, ip, iend-ip, OF_defaultNorm, OF_defaultNormLog);
if (ZSTD_isError(bhSize)) return ERROR(corruption_detected);
ip += bhSize;
}
@@ -650,7 +622,7 @@ static void ZSTD_decodeSequence(seq_t* seq, seqState_t* seqState)
0, 1, 3, 7, 0xF, 0x1F, 0x3F, 0x7F,
0xFF, 0x1FF, 0x3FF, 0x7FF, 0xFFF, 0x1FFF, 0x3FFF, 0x7FFF,
0xFFFF, 0x1FFFF, 0x3FFFF, 0x7FFFF, 0xFFFFF, 0x1FFFFF, 0x3FFFFF, 0x7FFFFF,
0xFFFFFF, 0x1FFFFFF, 0x3FFFFFF, /*fake*/ 1, 1, 1, 1, 1 };
0xFFFFFF, 0x1FFFFFF, 0x3FFFFFF, /*fake*/ 1, 1 };
/* sequence */
{ size_t offset;
@@ -660,7 +632,7 @@ static void ZSTD_decodeSequence(seq_t* seq, seqState_t* seqState)
offset = OF_base[ofCode] + BIT_readBits(&(seqState->DStream), ofBits); /* <= 26 bits */
if (MEM_32bits()) BIT_reloadDStream(&(seqState->DStream));
}
if (offset < ZSTD_REP_NUM) {
if (llCode == 0 && offset <= 1) offset = 1-offset;
@@ -678,7 +650,7 @@ static void ZSTD_decodeSequence(seq_t* seq, seqState_t* seqState)
} else {
offset -= ZSTD_REP_MOVE;
seqState->prevOffset[2] = seqState->prevOffset[1];
seqState->prevOffset[1] = seqState->prevOffset[0];
seqState->prevOffset[1] = seqState->prevOffset[0];
seqState->prevOffset[0] = offset;
}
seq->offset = offset;