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improved level 3

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This commit is contained in:
Yann Collet 2016-08-24 01:10:42 +02:00
parent 17e482efdd
commit c54692faeb
1 changed files with 36 additions and 9 deletions
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45
lib/compress/zstd_compress.c
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@ -1232,9 +1232,20 @@ void ZSTD_compressBlock_doubleFast_generic(ZSTD_CCtx* cctx,
offset = (U32)(ip-matchLong); offset = (U32)(ip-matchLong);
while (((ip>anchor) & (matchLong>lowest)) && (ip[-1] == matchLong[-1])) { ip--; matchLong--; mLength++; } /* catch up */ while (((ip>anchor) & (matchLong>lowest)) && (ip[-1] == matchLong[-1])) { ip--; matchLong--; mLength++; } /* catch up */
} else if ( (matchIndexS > lowestIndex) && (MEM_read32(match) == MEM_read32(ip)) ) { } else if ( (matchIndexS > lowestIndex) && (MEM_read32(match) == MEM_read32(ip)) ) {
mLength = ZSTD_count(ip+4, match+4, iend) + 4; size_t const h3 = ZSTD_hashPtr(ip+1, hBitsL, 8);
offset = (U32)(ip-match); U32 const matchIndex3 = hashLong[h3];
while (((ip>anchor) & (match>lowest)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */ const BYTE* match3 = base + matchIndex3;
hashLong[h3] = current + 1;
if ( (matchIndex3 > lowestIndex) && (MEM_read64(match3) == MEM_read64(ip+1)) ) {
mLength = ZSTD_count(ip+9, match3+8, iend) + 8;
ip++;
offset = (U32)(ip-match3);
while (((ip>anchor) & (match3>lowest)) && (ip[-1] == match3[-1])) { ip--; match3--; mLength++; } /* catch up */
} else {
mLength = ZSTD_count(ip+4, match+4, iend) + 4;
offset = (U32)(ip-match);
while (((ip>anchor) & (match>lowest)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */
}
} else { } else {
ip += ((ip-anchor) >> g_searchStrength) + 1; ip += ((ip-anchor) >> g_searchStrength) + 1;
continue; continue;
@ -1361,16 +1372,32 @@ static void ZSTD_compressBlock_doubleFast_extDict_generic(ZSTD_CCtx* ctx,
offset_2 = offset_1; offset_2 = offset_1;
offset_1 = offset; offset_1 = offset;
ZSTD_storeSeq(seqStorePtr, ip-anchor, anchor, offset + ZSTD_REP_MOVE, mLength-MINMATCH); ZSTD_storeSeq(seqStorePtr, ip-anchor, anchor, offset + ZSTD_REP_MOVE, mLength-MINMATCH);
} else if ((matchIndex > lowestIndex) && (MEM_read32(match) == MEM_read32(ip))) { } else if ((matchIndex > lowestIndex) && (MEM_read32(match) == MEM_read32(ip))) {
const BYTE* matchEnd = matchIndex < dictLimit ? dictEnd : iend; size_t const h3 = ZSTD_hashPtr(ip+1, hBitsL, 8);
const BYTE* lowMatchPtr = matchIndex < dictLimit ? dictStart : lowPrefixPtr; U32 const matchIndex3 = hashLong[h3];
const BYTE* const match3Base = matchIndex3 < dictLimit ? dictBase : base;
const BYTE* match3 = match3Base + matchIndex3;
U32 offset; U32 offset;
mLength = ZSTD_count_2segments(ip+4, match+4, iend, matchEnd, lowPrefixPtr) + 4; hashLong[h3] = current + 1;
while (((ip>anchor) & (match>lowMatchPtr)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */ if ( (matchIndex3 > lowestIndex) && (MEM_read64(match3) == MEM_read64(ip+1)) ) {
offset = current - matchIndex; const BYTE* matchEnd = matchIndex3 < dictLimit ? dictEnd : iend;
const BYTE* lowMatchPtr = matchIndex3 < dictLimit ? dictStart : lowPrefixPtr;
mLength = ZSTD_count_2segments(ip+9, match3+8, iend, matchEnd, lowPrefixPtr) + 8;
ip++;
offset = current+1 - matchIndex3;
while (((ip>anchor) & (match3>lowMatchPtr)) && (ip[-1] == match3[-1])) { ip--; match3--; mLength++; } /* catch up */
} else {
const BYTE* matchEnd = matchIndex < dictLimit ? dictEnd : iend;
const BYTE* lowMatchPtr = matchIndex < dictLimit ? dictStart : lowPrefixPtr;
mLength = ZSTD_count_2segments(ip+4, match+4, iend, matchEnd, lowPrefixPtr) + 4;
offset = current - matchIndex;
while (((ip>anchor) & (match>lowMatchPtr)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */
}
offset_2 = offset_1; offset_2 = offset_1;
offset_1 = offset; offset_1 = offset;
ZSTD_storeSeq(seqStorePtr, ip-anchor, anchor, offset + ZSTD_REP_MOVE, mLength-MINMATCH); ZSTD_storeSeq(seqStorePtr, ip-anchor, anchor, offset + ZSTD_REP_MOVE, mLength-MINMATCH);
} else { } else {
ip += ((ip-anchor) >> g_searchStrength) + 1; ip += ((ip-anchor) >> g_searchStrength) + 1;
continue; continue;
@ -3043,7 +3070,7 @@ static const ZSTD_compressionParameters ZSTD_defaultCParameters[4][ZSTD_MAX_CLEV
{ 18, 12, 12, 1, 7, 16, ZSTD_fast }, /* level 0 - not used */ { 18, 12, 12, 1, 7, 16, ZSTD_fast }, /* level 0 - not used */
{ 19, 13, 14, 1, 7, 16, ZSTD_fast }, /* level 1 */ { 19, 13, 14, 1, 7, 16, ZSTD_fast }, /* level 1 */
{ 19, 15, 16, 1, 6, 16, ZSTD_fast }, /* level 2 */ { 19, 15, 16, 1, 6, 16, ZSTD_fast }, /* level 2 */
{ 20, 16, 18, 1, 5, 16, ZSTD_dfast }, /* level 3 */ { 20, 16, 17, 1, 5, 16, ZSTD_dfast }, /* level 3 */
{ 20, 13, 17, 2, 5, 16, ZSTD_greedy }, /* level 4.*/ { 20, 13, 17, 2, 5, 16, ZSTD_greedy }, /* level 4.*/
{ 20, 15, 18, 3, 5, 16, ZSTD_greedy }, /* level 5 */ { 20, 15, 18, 3, 5, 16, ZSTD_greedy }, /* level 5 */
{ 21, 16, 19, 2, 5, 16, ZSTD_lazy }, /* level 6 */ { 21, 16, 19, 2, 5, 16, ZSTD_lazy }, /* level 6 */