AuroraMiddleware/lz4
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sligthly improved decompression speed

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This commit is contained in:
Yann Collet 2015-07-16 08:55:48 +01:00
parent a3c6daba6e
commit 795a2cdb1b
1 changed files with 12 additions and 12 deletions
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24
lib/lz4.c
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@ -199,8 +199,6 @@ static size_t LZ4_read_ARCH(const void* p)
} }
static void LZ4_copy4(void* dstPtr, const void* srcPtr) { memcpy(dstPtr, srcPtr, 4); }
static void LZ4_copy8(void* dstPtr, const void* srcPtr) { memcpy(dstPtr, srcPtr, 8); } static void LZ4_copy8(void* dstPtr, const void* srcPtr) { memcpy(dstPtr, srcPtr, 8); }
/* customized version of memcpy, which may overwrite up to 7 bytes beyond dstEnd */ /* customized version of memcpy, which may overwrite up to 7 bytes beyond dstEnd */
@ -210,6 +208,7 @@ static void LZ4_wildCopy(void* dstPtr, const void* srcPtr, void* dstEnd)
const BYTE* s = (const BYTE*)srcPtr; const BYTE* s = (const BYTE*)srcPtr;
BYTE* e = (BYTE*)dstEnd; BYTE* e = (BYTE*)dstEnd;
do { LZ4_copy8(d,s); d+=8; s+=8; } while (d<e); do { LZ4_copy8(d,s); d+=8; s+=8; } while (d<e);
//do { memcpy(d,s,16); d+=16; s+=16; } while (d<e);
} }
@ -1163,7 +1162,7 @@ FORCE_INLINE int LZ4_decompress_generic(
s = *ip++; s = *ip++;
length += s; length += s;
} }
while (likely((endOnInput)?ip<iend-RUN_MASK:1) && (s==255)); while ( likely(endOnInput ? ip<iend-RUN_MASK : 1) && (s==255) );
if ((safeDecode) && unlikely((size_t)(op+length)<(size_t)(op))) goto _output_error; /* overflow detection */ if ((safeDecode) && unlikely((size_t)(op+length)<(size_t)(op))) goto _output_error; /* overflow detection */
if ((safeDecode) && unlikely((size_t)(ip+length)<(size_t)(ip))) goto _output_error; /* overflow detection */ if ((safeDecode) && unlikely((size_t)(ip+length)<(size_t)(ip))) goto _output_error; /* overflow detection */
} }
@ -1192,8 +1191,9 @@ FORCE_INLINE int LZ4_decompress_generic(
ip += length; op = cpy; ip += length; op = cpy;
/* get offset */ /* get offset */
match = cpy - LZ4_readLE16(ip); ip+=2; const size_t offset = LZ4_readLE16(ip); ip+=2;
if ((checkOffset) && (unlikely(match < lowLimit))) goto _output_error; /* Error : offset outside destination buffer */ match = op - offset;
if ((checkOffset) && (unlikely(match < lowLimit))) goto _output_error; /* Error : offset outside buffers */
/* get matchlength */ /* get matchlength */
length = token & ML_MASK; length = token & ML_MASK;
@ -1223,12 +1223,12 @@ FORCE_INLINE int LZ4_decompress_generic(
} }
else else
{ {
/* match encompass external dictionary and current segment */ /* match encompass external dictionary and current block */
size_t copySize = (size_t)(lowPrefix-match); size_t copySize = (size_t)(lowPrefix-match);
memcpy(op, dictEnd - copySize, copySize); memcpy(op, dictEnd - copySize, copySize);
op += copySize; op += copySize;
copySize = length - copySize; copySize = length - copySize;
if (copySize > (size_t)(op-lowPrefix)) /* overlap within current segment */ if (copySize > (size_t)(op-lowPrefix)) /* overlap copy */
{ {
BYTE* const endOfMatch = op + copySize; BYTE* const endOfMatch = op + copySize;
const BYTE* copyFrom = lowPrefix; const BYTE* copyFrom = lowPrefix;
@ -1243,17 +1243,17 @@ FORCE_INLINE int LZ4_decompress_generic(
continue; continue;
} }
/* copy repeated sequence */ /* copy match within block */
cpy = op + length; cpy = op + length;
if (unlikely((op-match)<8)) if (unlikely(offset<8))
{ {
const size_t dec64 = dec64table[op-match]; const size_t dec64 = dec64table[offset];
op[0] = match[0]; op[0] = match[0];
op[1] = match[1]; op[1] = match[1];
op[2] = match[2]; op[2] = match[2];
op[3] = match[3]; op[3] = match[3];
match += dec32table[op-match]; match += dec32table[offset];
LZ4_copy4(op+4, match); memcpy(op+4, match, 4);
op += 8; match -= dec64; op += 8; match -= dec64;
} else { LZ4_copy8(op, match); op+=8; match+=8; } } else { LZ4_copy8(op, match); op+=8; match+=8; }