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Initial Repcode Check Support for Ext Dict Ctx

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This commit is contained in:
W. Felix Handte 2018-05-01 16:21:18 -04:00
parent 8d24ff0353
commit 70a537d1d7
1 changed files with 38 additions and 4 deletions
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42
lib/compress/zstd_fast.c
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@ -87,10 +87,20 @@ size_t ZSTD_compressBlock_fast_generic(
U32 const current = (U32)(ip-base);
U32 const matchIndex = hashTable[h];
const BYTE* match = base + matchIndex;
const int repIndex = current + 1 - offset_1;
const BYTE* repBase = hasDict == ZSTD_hasDictMatchState && repIndex < lowestIndex ? dictBase - dictIndexDelta : base;
const BYTE* repMatch = repBase + repIndex;
hashTable[h] = current; /* update hash table */
if ((hasDict != ZSTD_hasDictMatchState || current >= lowestIndex + offset_1)
&& (offset_1 > 0) & (MEM_read32(ip+1-offset_1) == MEM_read32(ip+1))) {
if (hasDict == ZSTD_hasDictMatchState
&& (((U32)((lowestIndex-1) - (U32)repIndex) >= 3) /* intentional underflow */)
&& (MEM_read32(repMatch) == MEM_read32(ip+1)) ) {
const BYTE* repMatchEnd = repIndex < lowestIndex ? 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 (hasDict == ZSTD_noDictMatchState
&& (offset_1 > 0) & (MEM_read32(repMatch) == MEM_read32(ip+1))) {
mLength = ZSTD_count(ip+1+4, ip+1+4-offset_1, iend) + 4;
ip++;
ZSTD_storeSeq(seqStore, ip-anchor, anchor, 0, mLength-MINMATCH);
@ -109,7 +119,6 @@ size_t ZSTD_compressBlock_fast_generic(
mLength = ZSTD_count_2segments(ip+4, dictMatch+4, iend, dictEnd, istart) + 4;
{ U32 const offset = (U32)(current-dictMatchIndex-dictIndexDelta);
DEBUGLOG(6, "ip %p (%u) dictMatch %p (%u) idxDelta %u", ip, current, dictMatch, dictMatchIndex, dictIndexDelta);
while (((ip>anchor) & (dictMatch>dictLowest)) && (ip[-1] == dictMatch[-1])) { ip--; dictMatch--; mLength++; } /* catch up */
offset_2 = offset_1;
offset_1 = offset;
@ -139,6 +148,31 @@ size_t ZSTD_compressBlock_fast_generic(
hashTable[ZSTD_hashPtr(base+current+2, hlog, mls)] = current+2; /* here because current+2 could be > iend-8 */
hashTable[ZSTD_hashPtr(ip-2, hlog, mls)] = (U32)(ip-2-base);
/* check immediate repcode */
if (hasDict == ZSTD_hasDictMatchState) {
while (ip <= ilimit) {
U32 const current2 = (U32)(ip-base);
int const repIndex2 = current2 - offset_2;
const BYTE* repMatch2 = hasDict == ZSTD_hasDictMatchState
&& repIndex2 < lowestIndex ?
dictBase - dictIndexDelta + repIndex2 :
base + repIndex2;
if ( (((U32)((lowestIndex-1) - (U32)repIndex2) >= 3)) /* intentional overflow */
&& (MEM_read32(repMatch2) == MEM_read32(ip)) ) {
const BYTE* const repEnd2 = repIndex2 < lowestIndex ? dictEnd : iend;
size_t const repLength2 = ZSTD_count_2segments(ip+4, repMatch2+4, iend, repEnd2, istart) + 4;
U32 tmpOffset = offset_2; offset_2 = offset_1; offset_1 = tmpOffset; /* swap offset_2 <=> offset_1 */
ZSTD_storeSeq(seqStore, 0, anchor, 0, repLength2-MINMATCH);
hashTable[ZSTD_hashPtr(ip, hlog, mls)] = current2;
ip += repLength2;
anchor = ip;
continue;
}
break;
}
}
if (hasDict == ZSTD_noDictMatchState) {
while ( (ip <= ilimit)
&& (hasDict != ZSTD_hasDictMatchState || ip - offset_2 >= istart)
&& ( (offset_2>0)
@ -151,7 +185,7 @@ size_t ZSTD_compressBlock_fast_generic(
ip += rLength;
anchor = ip;
continue; /* faster when present ... (?) */
} } }
} } } }
/* save reps for next block */
rep[0] = offset_1 ? offset_1 : offsetSaved;