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Adjust match backwards count args

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This commit is contained in:
senhuang42 2020-10-14 15:23:03 -04:00
parent bf0d559449
commit 3f99c9b38d
1 changed files with 5 additions and 7 deletions
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12
lib/compress/zstd_ldm.c
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@ -161,17 +161,15 @@ static size_t ZSTD_ldm_countBackwardsMatch(
* On reaching `pMatchBase`, start counting from mEnd */ * On reaching `pMatchBase`, start counting from mEnd */
static size_t ZSTD_ldm_countBackwardsMatch_2segments( static size_t ZSTD_ldm_countBackwardsMatch_2segments(
const BYTE* pIn, const BYTE* pAnchor, const BYTE* pIn, const BYTE* pAnchor,
const BYTE* pMatch, const BYTE* pMatchBase, const BYTE* mEnd) const BYTE* pMatch, const BYTE* pMatchBase, const BYTE* dictStart, const BYTE* mEnd)
{ {
const BYTE* const vBegin = MAX(pIn - (pMatch - pMatchBase), pAnchor); size_t const matchLength = ZSTD_ldm_countBackwardsMatch(pIn, pAnchor, pMatch, pMatchBase);
size_t const matchLength = ZSTD_ldm_countBackwardsMatch(pIn, vBegin, pMatch, pMatchBase); if (pMatch - matchLength != pMatchBase || pMatchBase == dictStart) {
if (pMatch - matchLength != pMatchBase) {
return matchLength; return matchLength;
} }
DEBUGLOG(7, "ZSTD_ldm_countBackwardsMatch_2segments: found a 2-parts backwards match (current length==%zu)", matchLength); DEBUGLOG(7, "ZSTD_ldm_countBackwardsMatch_2segments: found a 2-parts backwards match (current length==%zu)", matchLength);
DEBUGLOG(7, "distance from pMatch to start = %zi", pMatch - pMatchBase);
DEBUGLOG(7, "final backwards match length = %zu", matchLength + ZSTD_ldm_countBackwardsMatch(pIn - matchLength, pAnchor, mEnd, pMatchBase)); DEBUGLOG(7, "final backwards match length = %zu", matchLength + ZSTD_ldm_countBackwardsMatch(pIn - matchLength, pAnchor, mEnd, pMatchBase));
return matchLength + ZSTD_ldm_countBackwardsMatch(pIn - matchLength, pAnchor, mEnd, pMatchBase); return matchLength + ZSTD_ldm_countBackwardsMatch(pIn - matchLength, pAnchor, mEnd, dictStart);
} }
/** ZSTD_ldm_fillFastTables() : /** ZSTD_ldm_fillFastTables() :
@ -350,7 +348,7 @@ static size_t ZSTD_ldm_generateSequences_internal(
} }
curBackwardMatchLength = curBackwardMatchLength =
ZSTD_ldm_countBackwardsMatch_2segments(ip, anchor, pMatch, ZSTD_ldm_countBackwardsMatch_2segments(ip, anchor, pMatch,
lowMatchPtr, dictEnd); lowMatchPtr, dictStart, dictEnd);
curTotalMatchLength = curForwardMatchLength + curTotalMatchLength = curForwardMatchLength +
curBackwardMatchLength; curBackwardMatchLength;
} else { /* !extDict */ } else { /* !extDict */