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Refactor ZSTD_dfast to Use `goto`s

dev
W. Felix Handte 2018-05-16 14:55:20 -04:00
parent 43606f9c83
commit 1850025156
1 changed files with 84 additions and 62 deletions
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146
lib/compress/zstd_double_fast.c
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@ -106,6 +106,7 @@ size_t ZSTD_compressBlock_doubleFast_generic(
/* Main Search Loop */
while (ip < ilimit) { /* < instead of <=, because repcode check at (ip+1) */
size_t mLength;
U32 offset;
size_t const h2 = ZSTD_hashPtr(ip, hBitsL, 8);
size_t const h = ZSTD_hashPtr(ip, hBitsS, mls);
U32 const current = (U32)(ip-base);
@ -120,6 +121,7 @@ size_t ZSTD_compressBlock_doubleFast_generic(
base + repIndex;
hashLong[h2] = hashSmall[h] = current; /* update hash tables */
/* check dictMatchState repcode */
if (dictMode == ZSTD_dictMatchState
&& ((U32)((prefixLowestIndex-1) - repIndex) >= 3 /* intentional underflow */)
&& (MEM_read32(repMatch) == MEM_read32(ip+1)) ) {
@ -127,73 +129,93 @@ size_t ZSTD_compressBlock_doubleFast_generic(
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 ( dictMode == ZSTD_noDict
&& ((offset_1 > 0) & (MEM_read32(ip+1-offset_1) == MEM_read32(ip+1)))) {
goto _match_stored;
}
/* check noDict repcode */
if ( dictMode == ZSTD_noDict
&& ((offset_1 > 0) & (MEM_read32(ip+1-offset_1) == 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);
} else {
U32 offset;
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 */
} else if ( (matchIndexS > prefixLowestIndex) && (MEM_read32(match) == MEM_read32(ip)) ) {
size_t const hl3 = ZSTD_hashPtr(ip+1, hBitsL, 8);
U32 const matchIndexL3 = hashLong[hl3];
const BYTE* matchL3 = base + matchIndexL3;
hashLong[hl3] = current + 1;
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 */
}
} 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, prefixLowest) + 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+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 */
} 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;
}
offset_2 = offset_1;
offset_1 = offset;
ZSTD_storeSeq(seqStore, ip-anchor, anchor, offset + ZSTD_REP_MOVE, mLength-MINMATCH);
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 prefix short match */
if ( (matchIndexS > prefixLowestIndex) && (MEM_read32(match) == MEM_read32(ip)) ) {
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 + 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 matches */
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, prefixLowest) + 8;
offset = (U32)(current - dictMatchIndexL - dictIndexDelta);
while (((ip>anchor) & (dictMatchL>dictLowest)) && (ip[-1] == dictMatchL[-1])) { ip--; dictMatchL--; mLength++; } /* catch up */
goto _match_found;
}
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, 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;
continue;
_match_found:
offset_2 = offset_1;
offset_1 = offset;
ZSTD_storeSeq(seqStore, ip-anchor, anchor, offset + ZSTD_REP_MOVE, mLength-MINMATCH);
_match_stored:
/* match found */
ip += mLength;
anchor = ip;