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Pull Match Found Stuff Out of the Loop

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This commit is contained in:
W. Felix Handte
2021-10-05 14:54:37 -04:00
parent 072ffaad67
commit a1ac7205d0
1 changed files with 92 additions and 79 deletions
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lib/compress/zstd_double_fast.c
+92 -79
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@@ -60,7 +60,6 @@ size_t ZSTD_compressBlock_doubleFast_singleSegment_generic(
const U32 hBitsS = cParams->chainLog;
const BYTE* const base = ms->window.base;
const BYTE* const istart = (const BYTE*)src;
const BYTE* ip = istart;
const BYTE* anchor = istart;
const U32 endIndex = (U32)((size_t)(istart - base) + srcSize);
/* presumes that, if there is a dictionary, it must be using Attach mode */
@@ -70,9 +69,14 @@ size_t ZSTD_compressBlock_doubleFast_singleSegment_generic(
const BYTE* const ilimit = iend - HASH_READ_SIZE;
U32 offset_1=rep[0], offset_2=rep[1];
U32 offsetSaved = 0;
size_t step = 1;
size_t mLength;
U32 offset;
U32 curr;
const size_t kStepIncr = 1 << kSearchStrength;
const BYTE* nextStep = ip + kStepIncr;
const BYTE* nextStep;
size_t step;
size_t hl0;
size_t hs0;
@@ -89,23 +93,34 @@ size_t ZSTD_compressBlock_doubleFast_singleSegment_generic(
const BYTE* matchl1;
// const BYTE* matchs1;
const BYTE* ip = istart;
const BYTE* ip1;
DEBUGLOG(5, "ZSTD_compressBlock_doubleFast_singleSegment_generic");
/* init */
ip += ((ip - prefixLowest) == 0);
{
U32 const curr = (U32)(ip - base);
U32 const windowLow = ZSTD_getLowestPrefixIndex(ms, curr, cParams->windowLog);
U32 const maxRep = curr - windowLow;
U32 const current = (U32)(ip - base);
U32 const windowLow = ZSTD_getLowestPrefixIndex(ms, current, cParams->windowLog);
U32 const maxRep = current - windowLow;
if (offset_2 > maxRep) offsetSaved = offset_2, offset_2 = 0;
if (offset_1 > maxRep) offsetSaved = offset_1, offset_1 = 0;
}
_start:
step = 1;
nextStep = ip + kStepIncr;
ip1 = ip + step;
if (ip1 >= ilimit) {
goto _cleanup;
}
/* Main Search Loop */
while (ip < ilimit) { /* < instead of <=, because repcode check at (ip+1) */
size_t mLength;
U32 offset;
U32 const curr = (U32)(ip-base);
do {
curr = (U32)(ip-base);
hl0 = ZSTD_hashPtr(ip, hBitsL, 8);
hs0 = ZSTD_hashPtr(ip, hBitsS, mls);
idxl0 = hashLong[hl0];
@@ -151,82 +166,80 @@ size_t ZSTD_compressBlock_doubleFast_singleSegment_generic(
#if defined(__aarch64__)
PREFETCH_L1(ip+256);
#endif
continue;
_search_next_long:
{ hl1 = ZSTD_hashPtr(ip+1, hBitsL, 8);
idxl1 = hashLong[hl1];
matchl1 = base + idxl1;
hashLong[hl1] = curr + 1;
/* check prefix long +1 match */
if (idxl1 > prefixLowestIndex) {
if (MEM_read64(matchl1) == MEM_read64(ip+1)) {
mLength = ZSTD_count(ip+9, matchl1+8, iend) + 8;
ip++;
offset = (U32)(ip-matchl1);
while (((ip>anchor) & (matchl1>prefixLowest)) && (ip[-1] == matchl1[-1])) { ip--; matchl1--; mLength++; } /* catch up */
goto _match_found;
}
}
}
/* if no long +1 match, explore the short match we found */
{
mLength = ZSTD_count(ip+4, matchs0+4, iend) + 4;
offset = (U32)(ip - matchs0);
while (((ip>anchor) & (matchs0>prefixLowest)) && (ip[-1] == matchs0[-1])) { ip--; matchs0--; mLength++; } /* catch up */
}
/* fall-through */
_match_found: /* requires ip, offset, mLength */
offset_2 = offset_1;
offset_1 = offset;
ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, offset + ZSTD_REP_MOVE, mLength-MINMATCH);
_match_stored:
/* match found */
ip += mLength;
anchor = ip;
if (ip <= ilimit) {
/* Complementary insertion */
/* done after iLimit test, as candidates could be > iend-8 */
{ U32 const indexToInsert = curr+2;
hashLong[ZSTD_hashPtr(base+indexToInsert, hBitsL, 8)] = indexToInsert;
hashLong[ZSTD_hashPtr(ip-2, hBitsL, 8)] = (U32)(ip-2-base);
hashSmall[ZSTD_hashPtr(base+indexToInsert, hBitsS, mls)] = indexToInsert;
hashSmall[ZSTD_hashPtr(ip-1, hBitsS, mls)] = (U32)(ip-1-base);
}
/* check immediate repcode */
while ( (ip <= ilimit)
&& ( (offset_2>0)
& (MEM_read32(ip) == MEM_read32(ip - offset_2)) )) {
/* store sequence */
size_t const rLength = ZSTD_count(ip+4, ip+4-offset_2, iend) + 4;
U32 const tmpOff = offset_2; offset_2 = offset_1; offset_1 = tmpOff; /* swap offset_2 <=> offset_1 */
hashSmall[ZSTD_hashPtr(ip, hBitsS, mls)] = (U32)(ip-base);
hashLong[ZSTD_hashPtr(ip, hBitsL, 8)] = (U32)(ip-base);
ZSTD_storeSeq(seqStore, 0, anchor, iend, 0, rLength-MINMATCH);
ip += rLength;
anchor = ip;
continue; /* faster when present ... (?) */
} }
step = 1;
nextStep = ip + kStepIncr;
} /* while (ip < ilimit) */
} while (ip < ilimit);
_cleanup:
/* save reps for next block */
rep[0] = offset_1 ? offset_1 : offsetSaved;
rep[1] = offset_2 ? offset_2 : offsetSaved;
/* Return the last literals size */
return (size_t)(iend - anchor);
_search_next_long:
{ hl1 = ZSTD_hashPtr(ip+1, hBitsL, 8);
idxl1 = hashLong[hl1];
matchl1 = base + idxl1;
hashLong[hl1] = curr + 1;
/* check prefix long +1 match */
if (idxl1 > prefixLowestIndex) {
if (MEM_read64(matchl1) == MEM_read64(ip+1)) {
mLength = ZSTD_count(ip+9, matchl1+8, iend) + 8;
ip++;
offset = (U32)(ip-matchl1);
while (((ip>anchor) & (matchl1>prefixLowest)) && (ip[-1] == matchl1[-1])) { ip--; matchl1--; mLength++; } /* catch up */
goto _match_found;
}
}
}
/* if no long +1 match, explore the short match we found */
{
mLength = ZSTD_count(ip+4, matchs0+4, iend) + 4;
offset = (U32)(ip - matchs0);
while (((ip>anchor) & (matchs0>prefixLowest)) && (ip[-1] == matchs0[-1])) { ip--; matchs0--; mLength++; } /* catch up */
}
/* fall-through */
_match_found: /* requires ip, offset, mLength */
offset_2 = offset_1;
offset_1 = offset;
ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, offset + ZSTD_REP_MOVE, mLength-MINMATCH);
_match_stored:
/* match found */
ip += mLength;
anchor = ip;
if (ip <= ilimit) {
/* Complementary insertion */
/* done after iLimit test, as candidates could be > iend-8 */
{ U32 const indexToInsert = curr+2;
hashLong[ZSTD_hashPtr(base+indexToInsert, hBitsL, 8)] = indexToInsert;
hashLong[ZSTD_hashPtr(ip-2, hBitsL, 8)] = (U32)(ip-2-base);
hashSmall[ZSTD_hashPtr(base+indexToInsert, hBitsS, mls)] = indexToInsert;
hashSmall[ZSTD_hashPtr(ip-1, hBitsS, mls)] = (U32)(ip-1-base);
}
/* check immediate repcode */
while ( (ip <= ilimit)
&& ( (offset_2>0)
& (MEM_read32(ip) == MEM_read32(ip - offset_2)) )) {
/* store sequence */
size_t const rLength = ZSTD_count(ip+4, ip+4-offset_2, iend) + 4;
U32 const tmpOff = offset_2; offset_2 = offset_1; offset_1 = tmpOff; /* swap offset_2 <=> offset_1 */
hashSmall[ZSTD_hashPtr(ip, hBitsS, mls)] = (U32)(ip-base);
hashLong[ZSTD_hashPtr(ip, hBitsL, 8)] = (U32)(ip-base);
ZSTD_storeSeq(seqStore, 0, anchor, iend, 0, rLength-MINMATCH);
ip += rLength;
anchor = ip;
continue; /* faster when present ... (?) */
} }
goto _start;
}