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Check Long + 1 Matches in Both Prefix and Dict in Bothe Short Match Paths

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This commit is contained in:
W. Felix Handte
2018-05-25 13:13:57 -04:00
parent 88b733b380
commit 5b292b5685
1 changed files with 51 additions and 37 deletions
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lib/compress/zstd_double_fast.c
+51 -37
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@@ -111,7 +111,7 @@ size_t ZSTD_compressBlock_doubleFast_generic(
size_t const h = ZSTD_hashPtr(ip, hBitsS, mls); size_t const h = ZSTD_hashPtr(ip, hBitsS, mls);
U32 const current = (U32)(ip-base); U32 const current = (U32)(ip-base);
U32 const matchIndexL = hashLong[h2]; U32 const matchIndexL = hashLong[h2];
U32 const matchIndexS = hashSmall[h]; U32 matchIndexS = hashSmall[h];
const BYTE* matchLong = base + matchIndexL; const BYTE* matchLong = base + matchIndexL;
const BYTE* match = base + matchIndexS; const BYTE* match = base + matchIndexS;
const U32 repIndex = current + 1 - offset_1; const U32 repIndex = current + 1 - offset_1;
@@ -165,54 +165,68 @@ size_t ZSTD_compressBlock_doubleFast_generic(
/* check prefix short match */ /* check prefix short match */
if ( (matchIndexS > prefixLowestIndex) && (MEM_read32(match) == MEM_read32(ip)) ) { if ( (matchIndexS > prefixLowestIndex) && (MEM_read32(match) == MEM_read32(ip)) ) {
size_t const hl3 = ZSTD_hashPtr(ip+1, hBitsL, 8); goto _search_next_long;
U32 const matchIndexL3 = hashLong[hl3];
const BYTE* matchL3 = base + matchIndexL3;
hashLong[hl3] = current + 1;
/* check prefix + 1 long match */
if ( (matchIndexL3 > prefixLowestIndex) && (MEM_read64(matchL3) == MEM_read64(ip+1)) ) {
mLength = ZSTD_count(ip+9, matchL3+8, iend) + 8;
ip++;
offset = (U32)(ip-matchL3);
while (((ip>anchor) & (matchL3>prefixLowest)) && (ip[-1] == matchL3[-1])) { ip--; matchL3--; mLength++; } /* catch up */
} else {
mLength = ZSTD_count(ip+4, match+4, iend) + 4;
offset = (U32)(ip-match);
while (((ip>anchor) & (match>prefixLowest)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */
}
goto _match_found;
} }
/* check dictMatchState short match */ /* check dictMatchState short match */
if (dictMode == ZSTD_dictMatchState) { if (dictMode == ZSTD_dictMatchState) {
U32 const dictMatchIndexS = dictHashSmall[h]; U32 const dictMatchIndexS = dictHashSmall[h];
const BYTE* dictMatchS = dictBase + dictMatchIndexS; match = dictBase + dictMatchIndexS;
assert(dictMatchS < dictEnd); matchIndexS = dictMatchIndexS + dictIndexDelta;
if (dictMatchS > dictLowest && MEM_read32(dictMatchS) == MEM_read32(ip)) { if (match > dictLowest && MEM_read32(match) == MEM_read32(ip)) {
size_t const hl3 = ZSTD_hashPtr(ip+1, hBitsL, 8); goto _search_next_long;
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, prefixLowest) + 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 */
}
goto _match_found;
} }
} }
ip += ((ip-anchor) >> kSearchStrength) + 1; ip += ((ip-anchor) >> kSearchStrength) + 1;
continue; continue;
_search_next_long:
{
size_t const hl3 = ZSTD_hashPtr(ip+1, hBitsL, 8);
U32 const matchIndexL3 = hashLong[hl3];
const BYTE* matchL3 = base + matchIndexL3;
hashLong[hl3] = current + 1;
/* check prefix long +1 match */
if ( (matchIndexL3 > prefixLowestIndex) && (MEM_read64(matchL3) == MEM_read64(ip+1)) ) {
mLength = ZSTD_count(ip+9, matchL3+8, iend) + 8;
ip++;
offset = (U32)(ip-matchL3);
while (((ip>anchor) & (matchL3>prefixLowest)) && (ip[-1] == matchL3[-1])) { ip--; matchL3--; mLength++; } /* catch up */
goto _match_found;
}
/* check dict long +1 match */
if (dictMode == ZSTD_dictMatchState) {
U32 const dictMatchIndexL3 = dictHashLong[hl3];
const BYTE* dictMatchL3 = dictBase + dictMatchIndexL3;
assert(dictMatchL3 < dictEnd);
if (dictMatchL3 > dictLowest && MEM_read64(dictMatchL3) == MEM_read64(ip+1)) {
mLength = ZSTD_count_2segments(ip+1+8, dictMatchL3+8, iend, dictEnd, prefixLowest) + 8;
ip++;
offset = (U32)(current + 1 - dictMatchIndexL3 - dictIndexDelta);
while (((ip>anchor) & (dictMatchL3>dictLowest)) && (ip[-1] == dictMatchL3[-1])) { ip--; dictMatchL3--; mLength++; } /* catch up */
goto _match_found;
}
}
}
/* if no long +1 match, explore the short match we found */
if (dictMode == ZSTD_dictMatchState && matchIndexS < prefixLowestIndex) {
mLength = ZSTD_count_2segments(ip+4, match+4, iend, dictEnd, istart) + 4;
offset = (U32)(current - matchIndexS);
while (((ip>anchor) & (match>dictLowest)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */
} else {
mLength = ZSTD_count(ip+4, match+4, iend) + 4;
offset = (U32)(ip - match);
while (((ip>anchor) & (match>prefixLowest)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */
}
/* fall-through */
_match_found: _match_found:
offset_2 = offset_1; offset_2 = offset_1;
offset_1 = offset; offset_1 = offset;