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compress:check more bytes to reduce ZSTD_count call

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Comparing 4B instead of comparing 1B in ZSTD_noDict
mode, thus it can avoid cases like match in match[ml]
but mismatch in match[ml-3]..match[ml-1]. So the call
count of ZSTD_count can be reduced.

Signed-off-by: Jun He <jun.he@arm.com>
Change-Id: I3449ea423d5c8e8344f75341f19a2d1643c703f6
This commit is contained in:
Jun He 2022-06-24 17:07:06 +08:00
parent cb6dc32635
commit ce52acd7dc
1 changed files with 4 additions and 2 deletions
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6
lib/compress/zstd_lazy.c
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@ -692,7 +692,8 @@ size_t ZSTD_HcFindBestMatch(
if ((dictMode != ZSTD_extDict) || matchIndex >= dictLimit) {
const BYTE* const match = base + matchIndex;
assert(matchIndex >= dictLimit); /* ensures this is true if dictMode != ZSTD_extDict */
if (match[ml] == ip[ml]) /* potentially better */
/* read 4B starting from (match + ml + 1 - sizeof(U32)) */
if (MEM_read32(match + ml - 3) == MEM_read32(ip + ml - 3)) /* potentially better */
currentMl = ZSTD_count(ip, match, iLimit);
} else {
const BYTE* const match = dictBase + matchIndex;
@ -1244,7 +1245,8 @@ size_t ZSTD_RowFindBestMatch(
if ((dictMode != ZSTD_extDict) || matchIndex >= dictLimit) {
const BYTE* const match = base + matchIndex;
assert(matchIndex >= dictLimit); /* ensures this is true if dictMode != ZSTD_extDict */
if (match[ml] == ip[ml]) /* potentially better */
/* read 4B starting from (match + ml + 1 - sizeof(U32)) */
if (MEM_read32(match + ml - 3) == MEM_read32(ip + ml - 3)) /* potentially better */
currentMl = ZSTD_count(ip, match, iLimit);
} else {
const BYTE* const match = dictBase + matchIndex;