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Find Dict Hash Table Matches

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This commit is contained in:
W. Felix Handte
2018-05-25 13:13:28 -04:00
parent 7a25f7ef5b
commit 50c5b2bb90
1 changed files with 30 additions and 0 deletions
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lib/compress/zstd_double_fast.c
+30
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@@ -139,6 +139,36 @@ size_t ZSTD_compressBlock_doubleFast_generic(
offset = (U32)(ip-match);
while (((ip>anchor) & (match>localLowest)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */
}
} else if (dictMode == ZSTD_dictMatchState) {
U32 const dictMatchIndexL = dictHashLong[h2];
U32 const dictMatchIndexS = dictHashSmall[h];
const BYTE* dictMatchL = dictBase + dictMatchIndexL;
const BYTE* dictMatchS = dictBase + dictMatchIndexS;
assert(dictMatchL < dictEnd);
assert(dictMatchS < dictEnd);
if (dictMatchL > dictLowest && MEM_read64(dictMatchL) == MEM_read64(ip)) {
mLength = ZSTD_count_2segments(ip+8, dictMatchL+8, iend, dictEnd, localLowest) + 8;
offset = (U32)(current - dictMatchIndexL - dictIndexDelta);
while (((ip>anchor) & (dictMatchL>dictLowest)) && (ip[-1] == dictMatchL[-1])) { ip--; dictMatchL--; mLength++; } /* catch up */
} else if (dictMatchS > dictLowest && MEM_read32(dictMatchS) == MEM_read32(ip)) {
size_t const hl3 = ZSTD_hashPtr(ip+1, hBitsL, 8);
U32 const dictMatchIndexL3 = dictHashLong[hl3];
const BYTE* dictMatchL3 = dictBase + dictMatchIndexL3;
assert(dictMatchL3 < dictEnd);
if (dictMatchL3 > dictLowest && MEM_read64(dictMatchL3) == MEM_read64(ip)) {
mLength = ZSTD_count_2segments(ip+1+8, dictMatchL3+8, iend, dictEnd, localLowest) + 8;
ip++;
offset = (U32)(current + 1 - dictMatchIndexL3 - dictIndexDelta);
while (((ip>anchor) & (dictMatchL3>dictLowest)) && (ip[-1] == dictMatchL3[-1])) { ip--; dictMatchL3--; mLength++; } /* catch up */
} else {
mLength = ZSTD_count_2segments(ip+4, dictMatchS+4, iend, dictEnd, istart) + 4;
offset = (U32)(current - dictMatchIndexS - dictIndexDelta);
while (((ip>anchor) & (dictMatchS>dictLowest)) && (ip[-1] == dictMatchS[-1])) { ip--; dictMatchS--; mLength++; } /* catch up */
}
} else {
ip += ((ip-anchor) >> kSearchStrength) + 1;
continue;
}
} else {
ip += ((ip-anchor) >> kSearchStrength) + 1;
continue;