lib/zstd
1
0
Fork 0
mirror of https://github.com/facebook/zstd.git synced 2025-11-03 20:33:11 +03:00
Code Activity

fix lazy parser

Browse Source
This commit is contained in:
Yann Collet
2016-07-03 01:23:58 +02:00
parent 92d75667e4
commit 9634f67107
1 changed files with 18 additions and 23 deletions
Download Patch File Download Diff File Expand all files Collapse all files

41
lib/compress/zstd_compress.c
View File

@@ -1721,17 +1721,15 @@ void ZSTD_compressBlock_lazy_generic(ZSTD_CCtx* ctx,
size_t* offsetPtr, size_t* offsetPtr,
U32 maxNbAttempts, U32 matchLengthSearch); U32 maxNbAttempts, U32 matchLengthSearch);
searchMax_f const searchMax = searchMethod ? ZSTD_BtFindBestMatch_selectMLS : ZSTD_HcFindBestMatch_selectMLS; searchMax_f const searchMax = searchMethod ? ZSTD_BtFindBestMatch_selectMLS : ZSTD_HcFindBestMatch_selectMLS;
U32 rep[ZSTD_REP_INIT]; U32 offset_1 = ctx->rep[0], offset_2 = ctx->rep[1], savedOffset=0;
/* init */ /* init */
ip += (ip==base); ip += (ip==base);
ctx->nextToUpdate3 = ctx->nextToUpdate; ctx->nextToUpdate3 = ctx->nextToUpdate;
{ U32 i; { U32 const maxRep = (U32)(ip-base);
U32 const maxRep = (U32)(ip-base); if (offset_2 > maxRep) savedOffset = offset_2, offset_2 = 0;
for (i=0; i<ZSTD_REP_INIT; i++) { if (offset_1 > maxRep) savedOffset = offset_1, offset_1 = 0;
rep[i]=ctx->rep[i]; }
if (rep[i]>maxRep) rep[i]=0;
} }
/* Match Loop */ /* Match Loop */
while (ip < ilimit) { while (ip < ilimit) {
@@ -1740,9 +1738,9 @@ void ZSTD_compressBlock_lazy_generic(ZSTD_CCtx* ctx,
const BYTE* start=ip+1; const BYTE* start=ip+1;
/* check repCode */ /* check repCode */
if ((rep[0]>0) & (MEM_read32(ip+1) == MEM_read32(ip+1 - rep[0]))) { if ((offset_1>0) & (MEM_read32(ip+1) == MEM_read32(ip+1 - offset_1))) {
/* repcode : we take it */ /* repcode : we take it */
matchLength = ZSTD_count(ip+1+EQUAL_READ32, ip+1+EQUAL_READ32-rep[0], iend) + EQUAL_READ32; matchLength = ZSTD_count(ip+1+EQUAL_READ32, ip+1+EQUAL_READ32-offset_1, iend) + EQUAL_READ32;
if (depth==0) goto _storeSequence; if (depth==0) goto _storeSequence;
} }
@@ -1762,8 +1760,8 @@ void ZSTD_compressBlock_lazy_generic(ZSTD_CCtx* ctx,
if (depth>=1) if (depth>=1)
while (ip<ilimit) { while (ip<ilimit) {
ip ++; ip ++;
if ((offset) && ((rep[0]>0) & (MEM_read32(ip) == MEM_read32(ip - rep[0])))) { if ((offset) && ((offset_1>0) & (MEM_read32(ip) == MEM_read32(ip - offset_1)))) {
size_t const mlRep = ZSTD_count(ip+EQUAL_READ32, ip+EQUAL_READ32-rep[0], iend) + EQUAL_READ32; size_t const mlRep = ZSTD_count(ip+EQUAL_READ32, ip+EQUAL_READ32-offset_1, iend) + EQUAL_READ32;
int const gain2 = (int)(mlRep * 3); int const gain2 = (int)(mlRep * 3);
int const gain1 = (int)(matchLength*3 - ZSTD_highbit32((U32)offset+1) + 1); int const gain1 = (int)(matchLength*3 - ZSTD_highbit32((U32)offset+1) + 1);
if ((mlRep >= EQUAL_READ32) && (gain2 > gain1)) if ((mlRep >= EQUAL_READ32) && (gain2 > gain1))
@@ -1781,8 +1779,8 @@ void ZSTD_compressBlock_lazy_generic(ZSTD_CCtx* ctx,
/* let's find an even better one */ /* let's find an even better one */
if ((depth==2) && (ip<ilimit)) { if ((depth==2) && (ip<ilimit)) {
ip ++; ip ++;
if ((offset) && ((rep[0]>0) & (MEM_read32(ip) == MEM_read32(ip - rep[0])))) { if ((offset) && ((offset_1>0) & (MEM_read32(ip) == MEM_read32(ip - offset_1)))) {
size_t const ml2 = ZSTD_count(ip+EQUAL_READ32, ip+EQUAL_READ32-rep[0], iend) + EQUAL_READ32; size_t const ml2 = ZSTD_count(ip+EQUAL_READ32, ip+EQUAL_READ32-offset_1, iend) + EQUAL_READ32;
int const gain2 = (int)(ml2 * 4); int const gain2 = (int)(ml2 * 4);
int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 1); int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 1);
if ((ml2 >= EQUAL_READ32) && (gain2 > gain1)) if ((ml2 >= EQUAL_READ32) && (gain2 > gain1))
@@ -1803,7 +1801,7 @@ void ZSTD_compressBlock_lazy_generic(ZSTD_CCtx* ctx,
if (offset) { if (offset) {
while ((start>anchor) && (start>base+offset-ZSTD_REP_MOVE) && (start[-1] == start[-1-offset+ZSTD_REP_MOVE])) /* only search for offset within prefix */ while ((start>anchor) && (start>base+offset-ZSTD_REP_MOVE) && (start[-1] == start[-1-offset+ZSTD_REP_MOVE])) /* only search for offset within prefix */
{ start--; matchLength++; } { start--; matchLength++; }
rep[1] = rep[0]; rep[0] = (U32)(offset - ZSTD_REP_MOVE); offset_2 = offset_1; offset_1 = (U32)(offset - ZSTD_REP_MOVE);
} }
/* store sequence */ /* store sequence */
@@ -1815,11 +1813,11 @@ _storeSequence:
/* check immediate repcode */ /* check immediate repcode */
while ( (ip <= ilimit) while ( (ip <= ilimit)
&& ((rep[1]>0) && ((offset_2>0)
& (MEM_read32(ip) == MEM_read32(ip - rep[1])) )) { & (MEM_read32(ip) == MEM_read32(ip - offset_2)) )) {
/* store sequence */ /* store sequence */
matchLength = ZSTD_count(ip+EQUAL_READ32, ip+EQUAL_READ32-rep[1], iend) + EQUAL_READ32; matchLength = ZSTD_count(ip+EQUAL_READ32, ip+EQUAL_READ32-offset_2, iend) + EQUAL_READ32;
offset = rep[1]; rep[1] = rep[0]; rep[0] = (U32)offset; /* swap repcodes */ offset = offset_2; offset_2 = offset_1; offset_1 = (U32)offset; /* swap repcodes */
ZSTD_storeSeq(seqStorePtr, 0, anchor, 0, matchLength-MINMATCH); ZSTD_storeSeq(seqStorePtr, 0, anchor, 0, matchLength-MINMATCH);
ip += matchLength; ip += matchLength;
anchor = ip; anchor = ip;
@@ -1827,11 +1825,8 @@ _storeSequence:
} } } }
/* Save reps for next block */ /* Save reps for next block */
{ int i; ctx->savedRep[0] = offset_1 ? offset_1 : savedOffset;
for (i=0; i<ZSTD_REP_NUM; i++) { ctx->savedRep[1] = offset_2 ? offset_2 : savedOffset;
if (!rep[i]) rep[i] = (U32)(iend - ctx->base) + 1; /* in case some zero are left */
ctx->savedRep[i] = rep[i];
} }
/* Last Literals */ /* Last Literals */
{ size_t const lastLLSize = iend - anchor; { size_t const lastLLSize = iend - anchor;