facebook
/
zstd
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Merge pull request #1318 from felixhandte/shadow-dict-matches 

Don't Search Dictionary Context When Working Context Search Resulted in Mismatch
dev
Yann Collet 2018-09-21 12:15:33 -07:00 committed by GitHub
parent c8ff5200f9 b76c888497
commit de6c75e4e5
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 33 additions and 29 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

54
lib/compress/zstd_double_fast.c
View File

@ -141,16 +141,16 @@ size_t ZSTD_compressBlock_doubleFast_generic(
goto _match_stored;
}
/* check prefix long match */
if ( (matchIndexL > prefixLowestIndex) && (MEM_read64(matchLong) == MEM_read64(ip)) ) {
mLength = ZSTD_count(ip+8, matchLong+8, iend) + 8;
offset = (U32)(ip-matchLong);
while (((ip>anchor) & (matchLong>prefixLowest)) && (ip[-1] == matchLong[-1])) { ip--; matchLong--; mLength++; } /* catch up */
goto _match_found;
}
/* check dictMatchState long match */
if (dictMode == ZSTD_dictMatchState) {
if (matchIndexL > prefixLowestIndex) {
/* check prefix long match */
if (MEM_read64(matchLong) == MEM_read64(ip)) {
mLength = ZSTD_count(ip+8, matchLong+8, iend) + 8;
offset = (U32)(ip-matchLong);
while (((ip>anchor) & (matchLong>prefixLowest)) && (ip[-1] == matchLong[-1])) { ip--; matchLong--; mLength++; } /* catch up */
goto _match_found;
}
} else if (dictMode == ZSTD_dictMatchState) {
/* check dictMatchState long match */
U32 const dictMatchIndexL = dictHashLong[h2];
const BYTE* dictMatchL = dictBase + dictMatchIndexL;
assert(dictMatchL < dictEnd);
@ -163,13 +163,13 @@ size_t ZSTD_compressBlock_doubleFast_generic(
}
}
/* check prefix short match */
if ( (matchIndexS > prefixLowestIndex) && (MEM_read32(match) == MEM_read32(ip)) ) {
goto _search_next_long;
}
/* check dictMatchState short match */
if (dictMode == ZSTD_dictMatchState) {
if (matchIndexS > prefixLowestIndex) {
/* check prefix short match */
if (MEM_read32(match) == MEM_read32(ip)) {
goto _search_next_long;
}
} else if (dictMode == ZSTD_dictMatchState) {
/* check dictMatchState short match */
U32 const dictMatchIndexS = dictHashSmall[h];
match = dictBase + dictMatchIndexS;
matchIndexS = dictMatchIndexS + dictIndexDelta;
@ -191,16 +191,16 @@ _search_next_long:
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) {
if (matchIndexL3 > prefixLowestIndex) {
if (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;
}
} else if (dictMode == ZSTD_dictMatchState) {
/* check dict long +1 match */
U32 const dictMatchIndexL3 = dictHashLong[hl3];
const BYTE* dictMatchL3 = dictBase + dictMatchIndexL3;
assert(dictMatchL3 < dictEnd);

8
lib/compress/zstd_fast.c
View File

@ -124,8 +124,7 @@ size_t ZSTD_compressBlock_fast_generic(
mLength = ZSTD_count(ip+1+4, ip+1+4-offset_1, iend) + 4;
ip++;
ZSTD_storeSeq(seqStore, ip-anchor, anchor, 0, mLength-MINMATCH);
} else if ( (matchIndex <= prefixStartIndex)
|| (MEM_read32(match) != MEM_read32(ip)) ) {
} else if ( (matchIndex <= prefixStartIndex) ) {
if (dictMode == ZSTD_dictMatchState) {
U32 const dictMatchIndex = dictHashTable[h];
const BYTE* dictMatch = dictBase + dictMatchIndex;
@ -151,6 +150,11 @@ size_t ZSTD_compressBlock_fast_generic(
ip += ((ip-anchor) >> kSearchStrength) + stepSize;
continue;
}
} else if (MEM_read32(match) != MEM_read32(ip)) {
/* it's not a match, and we're not going to check the dictionary */
assert(stepSize >= 1);
ip += ((ip-anchor) >> kSearchStrength) + stepSize;
continue;
} else {
/* found a regular match */
U32 const offset = (U32)(ip-match);