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minor speed improvements

dev
inikep 2016-04-07 11:35:17 +02:00
parent e47f33f980
commit 81a345b0ce
2 changed files with 13 additions and 11 deletions
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17
lib/zstd_compress.c
View File

@ -1319,6 +1319,7 @@ size_t ZSTD_HcFindBestMatch_generic (
const U32 minMatch = (mls == 3) ? 3 : 4;
size_t ml=minMatch-1;
#if 0
if (minMatch == 3) { /* HC3 match finder */
U32 const matchIndex3 = ZSTD_insertAndFindFirstIndexHash3 (zc, ip);
if (matchIndex3>lowLimit && current - matchIndex3<(1<<18)) {
@ -1326,8 +1327,7 @@ size_t ZSTD_HcFindBestMatch_generic (
size_t currentMl=0;
if ((!extDict) || matchIndex3 >= dictLimit) {
match = base + matchIndex3;
if (match[ml] == ip[ml]) /* potentially better */
currentMl = ZSTD_count(ip, match, iLimit);
if (match[ml] == ip[ml]) currentMl = ZSTD_count(ip, match, iLimit); /* potentially better */
} else {
match = dictBase + matchIndex3;
if (MEM_readMINMATCH(match, MINMATCH) == MEM_readMINMATCH(ip, MINMATCH)) /* assumption : matchIndex3 <= dictLimit-4 (by table construction) */
@ -1335,9 +1335,12 @@ size_t ZSTD_HcFindBestMatch_generic (
}
/* save best solution */
if (currentMl > ml) { ml = currentMl; *offsetPtr = ZSTD_REP_MOVE + current - matchIndex3; if (ip+currentMl == iLimit) return (ml>=MINMATCH) ? ml : 0; /* best possible, and avoid read overflow*/ }
}
if (currentMl > ml) {
ml = currentMl; *offsetPtr = ZSTD_REP_MOVE + current - matchIndex3;
if (ip+currentMl == iLimit) return (ml>=MINMATCH) ? ml : 0; /* best possible, and avoid read overflow*/
} }
}
#endif
/* HC4 match finder */
U32 matchIndex = ZSTD_insertAndFindFirstIndex (zc, ip, mls);
@ -1536,7 +1539,7 @@ static size_t ZSTD_insertBtAndFindBestMatch (
size_t bestLength = minMatch-1;
if (minMatch == 3) { /* HC3 match finder */
U32 matchIndex3 = ZSTD_insertAndFindFirstIndexHash3 (zc, ip);
U32 const matchIndex3 = ZSTD_insertAndFindFirstIndexHash3 (zc, ip);
if (matchIndex3>windowLow && (current - matchIndex3 < (1<<18))) {
const BYTE* match;
size_t currentMl=0;
@ -1545,8 +1548,8 @@ static size_t ZSTD_insertBtAndFindBestMatch (
if (match[bestLength] == ip[bestLength]) currentMl = ZSTD_count(ip, match, iend);
} else {
match = dictBase + matchIndex3;
if (MEM_readMINMATCH(match, minMatch) == MEM_readMINMATCH(ip, minMatch)) /* assumption : matchIndex3 <= dictLimit-4 (by table construction) */
currentMl = ZSTD_count_2segments(ip+minMatch, match+minMatch, iend, dictEnd, prefixStart) + minMatch;
if (MEM_readMINMATCH(match, MINMATCH) == MEM_readMINMATCH(ip, MINMATCH)) /* assumption : matchIndex3 <= dictLimit-4 (by table construction) */
currentMl = ZSTD_count_2segments(ip+MINMATCH, match+MINMATCH, iend, dictEnd, prefixStart) + MINMATCH;
}
/* save best solution */

7
lib/zstd_opt.h
View File

@ -247,8 +247,7 @@ static U32 ZSTD_insertBtAndGetAllMatches (
size_t bestLength = minMatch-1;
if (minMatch == 3) { /* HC3 match finder */
U32 matchIndex3 = ZSTD_insertAndFindFirstIndexHash3 (zc, ip);
U32 const matchIndex3 = ZSTD_insertAndFindFirstIndexHash3 (zc, ip);
if (matchIndex3>windowLow && (current - matchIndex3 < (1<<18))) {
const BYTE* match;
size_t currentMl=0;
@ -257,8 +256,8 @@ static U32 ZSTD_insertBtAndGetAllMatches (
if (match[bestLength] == ip[bestLength]) currentMl = ZSTD_count(ip, match, iLimit);
} else {
match = dictBase + matchIndex3;
if (MEM_readMINMATCH(match, minMatch) == MEM_readMINMATCH(ip, minMatch)) /* assumption : matchIndex3 <= dictLimit-4 (by table construction) */
currentMl = ZSTD_count_2segments(ip+minMatch, match+minMatch, iLimit, dictEnd, prefixStart) + minMatch;
if (MEM_readMINMATCH(match, MINMATCH) == MEM_readMINMATCH(ip, MINMATCH)) /* assumption : matchIndex3 <= dictLimit-4 (by table construction) */
currentMl = ZSTD_count_2segments(ip+MINMATCH, match+MINMATCH, iLimit, dictEnd, prefixStart) + MINMATCH;
}
/* save best solution */