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Implement First Repcode Check

dev
W. Felix Handte 2018-05-09 18:37:24 -04:00
parent 50c5b2bb90
commit 0998f10813
1 changed files with 15 additions and 1 deletions
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16
lib/compress/zstd_double_fast.c
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@ -110,9 +110,23 @@ size_t ZSTD_compressBlock_doubleFast_generic(
U32 const matchIndexS = hashSmall[h];
const BYTE* matchLong = base + matchIndexL;
const BYTE* match = base + matchIndexS;
const ptrdiff_t repIndex = (ptrdiff_t)current + 1 - offset_1;
const BYTE* repBase = (dictMode == ZSTD_dictMatchState
&& repIndex < (ptrdiff_t)localLowestIndex) ?
dictBase - dictIndexDelta : base;
const BYTE* repMatch = repBase + repIndex;
hashLong[h2] = hashSmall[h] = current; /* update hash tables */
if (dictMode == ZSTD_noDict && ((offset_1 > 0) & (MEM_read32(ip+1-offset_1) == MEM_read32(ip+1)))) {
if (dictMode == ZSTD_dictMatchState
&& (((U32)((localLowestIndex-1) - repIndex) >= 3 /* intentional underflow */)
& (repIndex > dictLowestLocalIndex))
&& (MEM_read32(repMatch) == MEM_read32(ip+1)) ) {
const BYTE* repMatchEnd = repIndex < (ptrdiff_t)localLowestIndex ? dictEnd : iend;
mLength = ZSTD_count_2segments(ip+1+4, repMatch+4, iend, repMatchEnd, istart) + 4;
ip++;
ZSTD_storeSeq(seqStore, ip-anchor, anchor, 0, mLength-MINMATCH);
} else if ( dictMode == ZSTD_noDict
&& (offset_1 > 0) & (MEM_read32(ip+1-offset_1) == MEM_read32(ip+1))) {
assert(offset_1 <= current); /* supposed guaranteed by construction */
/* favor repcode */
mLength = ZSTD_count(ip+1+4, ip+1+4-offset_1, iend) + 4;