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lz4opt: simplified match finder invocation to LZ4HC_FindLongerMatch()

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This commit is contained in:
Yann Collet 2017-11-08 17:11:51 -08:00
parent fa03a9d3d9
commit f93b595718
2 changed files with 12 additions and 21 deletions
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2
lib/lz4hc.c
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@ -304,7 +304,7 @@ int LZ4HC_InsertAndFindBestMatch(LZ4HC_CCtx_internal* const hc4, /* Index tabl
const BYTE* uselessPtr = ip;
/* note : LZ4HC_InsertAndGetWiderMatch() is able to modify the starting position of a match (*startpos),
* but this won't be the case here, as we define iLowLimit==ip,
* so LZ4HC_InsertAndGetWiderMatch() will not be allowed to search past ip */
* so LZ4HC_InsertAndGetWiderMatch() won't be allowed to search past ip */
return LZ4HC_InsertAndGetWiderMatch(hc4, ip, ip, iLimit, MINMATCH-1, matchpos, &uselessPtr, maxNbAttempts);
}

31
lib/lz4opt.h
View File

@ -70,32 +70,23 @@ LZ4_FORCE_INLINE int LZ4HC_sequencePrice(int litlen, int mlen)
/*-*************************************
* Match finder
***************************************/
LZ4_FORCE_INLINE
int LZ4HC_FindLongerMatch(LZ4HC_CCtx_internal* const ctx, /* Index table will be updated */
const BYTE* const ip, const BYTE* const iHighLimit,
int longest,
const BYTE** matchpos,
const int maxNbAttempts)
{
const BYTE* uselessPtr = ip;
return LZ4HC_InsertAndGetWiderMatch(ctx, ip, ip, iHighLimit, longest, matchpos, &uselessPtr, maxNbAttempts);
}
typedef struct {
int off;
int len;
} LZ4HC_match_t;
LZ4_FORCE_INLINE
LZ4HC_match_t LZ4HC_HashChain_GetAllMatches (LZ4HC_CCtx_internal* const ctx,
const BYTE* const ip, const BYTE* const iHighLimit,
size_t best_mlen, int nbSearches)
LZ4HC_match_t LZ4HC_FindLongerMatch(LZ4HC_CCtx_internal* const ctx,
const BYTE* ip, const BYTE* const iHighLimit,
int minLen, int nbSearches)
{
LZ4HC_match_t match = { 0 , 0 };
const BYTE* matchPtr = NULL;
int matchLength = LZ4HC_FindLongerMatch(ctx, ip, iHighLimit, (int)best_mlen, &matchPtr, nbSearches);
if ((size_t)matchLength <= best_mlen) return match;
/* note : LZ4HC_InsertAndGetWiderMatch() is able to modify the starting position of a match (*startpos),
* but this won't be the case here, as we define iLowLimit==ip,
* so LZ4HC_InsertAndGetWiderMatch() won't be allowed to search past ip */
int const matchLength = LZ4HC_InsertAndGetWiderMatch(ctx, ip, ip, iHighLimit, minLen, &matchPtr, &ip, nbSearches);
if (matchLength <= minLen) return match;
match.len = matchLength;
match.off = (int)(ip-matchPtr);
return match;
@ -135,7 +126,7 @@ static int LZ4HC_compress_optimal (
int best_mlen, best_off;
int cur, last_match_pos = 0;
LZ4HC_match_t const firstMatch = LZ4HC_HashChain_GetAllMatches(ctx, ip, matchlimit, MINMATCH-1, nbSearches);
LZ4HC_match_t const firstMatch = LZ4HC_FindLongerMatch(ctx, ip, matchlimit, MINMATCH-1, nbSearches);
if (firstMatch.len==0) { ip++; continue; }
if ((size_t)firstMatch.len > sufficient_len) {
@ -199,10 +190,10 @@ static int LZ4HC_compress_optimal (
DEBUGLOG(7, "search at rPos:%u", cur);
if (fullUpdate)
newMatch = LZ4HC_HashChain_GetAllMatches(ctx, curPtr, matchlimit, MINMATCH-1, nbSearches);
newMatch = LZ4HC_FindLongerMatch(ctx, curPtr, matchlimit, MINMATCH-1, nbSearches);
else
/* only test matches of minimum length; slightly faster, but misses a few bytes */
newMatch = LZ4HC_HashChain_GetAllMatches(ctx, curPtr, matchlimit, last_match_pos - cur, nbSearches);
newMatch = LZ4HC_FindLongerMatch(ctx, curPtr, matchlimit, last_match_pos - cur, nbSearches);
if (!newMatch.len) continue;
if ( ((size_t)newMatch.len > sufficient_len)