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ZSTD_compressBlock_lazy supports more reps

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This commit is contained in:
inikep 2016-03-16 12:57:07 +01:00
parent 0ac4a551b9
commit 62d694795d
2 changed files with 95 additions and 47 deletions
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93
lib/zstd_compress.c
View File

@ -1555,7 +1555,6 @@ void ZSTD_compressBlock_lazy_generic(ZSTD_CCtx* ctx,
const BYTE* const ilimit = iend - 8;
const BYTE* const base = ctx->base + ctx->dictLimit;
size_t offset_2=REPCODE_STARTVALUE, offset_1=REPCODE_STARTVALUE;
const U32 maxSearches = 1 << ctx->params.searchLog;
const U32 mls = ctx->params.searchLength;
@ -1565,6 +1564,10 @@ void ZSTD_compressBlock_lazy_generic(ZSTD_CCtx* ctx,
searchMax_f searchMax = searchMethod ? ZSTD_BtFindBestMatch_selectMLS : ZSTD_HcFindBestMatch_selectMLS;
/* init */
U32 rep[ZSTD_REP_NUM];
for (int i=0; i<ZSTD_REP_NUM; i++)
rep[i]=REPCODE_STARTVALUE;
ZSTD_resetSeqStore(seqStorePtr);
if ((ip-base) < REPCODE_STARTVALUE) ip = base + REPCODE_STARTVALUE;
@ -1575,10 +1578,14 @@ void ZSTD_compressBlock_lazy_generic(ZSTD_CCtx* ctx,
const BYTE* start=ip+1;
/* check repCode */
if (MEM_read32(ip+1) == MEM_read32(ip+1 - offset_1)) {
/* repcode : we take it */
matchLength = ZSTD_count(ip+1+MINMATCH, ip+1+MINMATCH-offset_1, iend) + MINMATCH;
if (depth==0) goto _storeSequence;
for (int i=0; i<1; i++) {
if (MEM_read32(ip+1) == MEM_read32(ip+1 - rep[i])) {
/* repcode : we take it */
matchLength = ZSTD_count(ip+1+MINMATCH, ip+1+MINMATCH-rep[i], iend) + MINMATCH;
offset = (ZSTD_REP_NUM - 1) - i;
if (depth==0) goto _storeSequence;
break;
}
}
{
@ -1586,7 +1593,7 @@ void ZSTD_compressBlock_lazy_generic(ZSTD_CCtx* ctx,
size_t offsetFound = 99999999;
size_t ml2 = searchMax(ctx, ip, iend, &offsetFound, maxSearches, mls);
if (ml2 > matchLength)
matchLength = ml2, start = ip, offset=offsetFound;
matchLength = ml2, start = ip, offset=offsetFound + (ZSTD_REP_NUM - 1);
}
if (matchLength < MINMATCH) {
@ -1598,12 +1605,12 @@ void ZSTD_compressBlock_lazy_generic(ZSTD_CCtx* ctx,
if (depth>=1)
while (ip<ilimit) {
ip ++;
if ((offset) && (MEM_read32(ip) == MEM_read32(ip - offset_1))) {
size_t mlRep = ZSTD_count(ip+MINMATCH, ip+MINMATCH-offset_1, iend) + MINMATCH;
if ((offset >= ZSTD_REP_NUM) && (MEM_read32(ip) == MEM_read32(ip - rep[0]))) {
size_t mlRep = ZSTD_count(ip+MINMATCH, ip+MINMATCH-rep[0], iend) + MINMATCH;
int gain2 = (int)(mlRep * 3);
int gain1 = (int)(matchLength*3 - ZSTD_highbit((U32)offset+1) + 1);
if ((mlRep >= MINMATCH) && (gain2 > gain1))
matchLength = mlRep, offset = 0, start = ip;
matchLength = mlRep, offset = 0 + (ZSTD_REP_NUM - 1), start = ip;
}
{
size_t offset2=999999;
@ -1611,19 +1618,19 @@ void ZSTD_compressBlock_lazy_generic(ZSTD_CCtx* ctx,
int gain2 = (int)(ml2*4 - ZSTD_highbit((U32)offset2+1)); /* raw approx */
int gain1 = (int)(matchLength*4 - ZSTD_highbit((U32)offset+1) + 4);
if ((ml2 >= MINMATCH) && (gain2 > gain1)) {
matchLength = ml2, offset = offset2, start = ip;
matchLength = ml2, offset = offset2 + (ZSTD_REP_NUM - 1), start = ip;
continue; /* search a better one */
} }
/* let's find an even better one */
if ((depth==2) && (ip<ilimit)) {
ip ++;
if ((offset) && (MEM_read32(ip) == MEM_read32(ip - offset_1))) {
size_t ml2 = ZSTD_count(ip+MINMATCH, ip+MINMATCH-offset_1, iend) + MINMATCH;
if ((offset >= ZSTD_REP_NUM) && (MEM_read32(ip) == MEM_read32(ip - rep[0]))) {
size_t ml2 = ZSTD_count(ip+MINMATCH, ip+MINMATCH-rep[0], iend) + MINMATCH;
int gain2 = (int)(ml2 * 4);
int gain1 = (int)(matchLength*4 - ZSTD_highbit((U32)offset+1) + 1);
if ((ml2 >= MINMATCH) && (gain2 > gain1))
matchLength = ml2, offset = 0, start = ip;
matchLength = ml2, offset = 0 + (ZSTD_REP_NUM - 1), start = ip;
}
{
size_t offset2=999999;
@ -1631,35 +1638,37 @@ void ZSTD_compressBlock_lazy_generic(ZSTD_CCtx* ctx,
int gain2 = (int)(ml2*4 - ZSTD_highbit((U32)offset2+1)); /* raw approx */
int gain1 = (int)(matchLength*4 - ZSTD_highbit((U32)offset+1) + 7);
if ((ml2 >= MINMATCH) && (gain2 > gain1)) {
matchLength = ml2, offset = offset2, start = ip;
matchLength = ml2, offset = offset2 + (ZSTD_REP_NUM - 1), start = ip;
continue;
} } }
break; /* nothing found : store previous solution */
}
/* catch up */
if (offset) {
while ((start>anchor) && (start>base+offset) && (start[-1] == start[-1-offset])) /* only search for offset within prefix */
if (offset >= ZSTD_REP_NUM) {
while ((start>anchor) && (start>base+offset-(ZSTD_REP_NUM-1)) && (start[-1] == start[-1-offset+(ZSTD_REP_NUM-1)])) /* only search for offset within prefix */
{ start--; matchLength++; }
offset_2 = offset_1; offset_1 = offset;
}
/* store sequence */
_storeSequence:
{
if (offset >= ZSTD_REP_NUM) {
rep[1] = rep[0]; rep[0] = offset - (ZSTD_REP_NUM - 1);
}
size_t litLength = start - anchor;
ZSTD_storeSeq(seqStorePtr, litLength, anchor, offset + ZSTD_REP_NUM - 1, matchLength-MINMATCH);
ZSTD_storeSeq(seqStorePtr, litLength, anchor, offset, matchLength-MINMATCH);
anchor = ip = start + matchLength;
}
/* check immediate repcode */
while ( (ip <= ilimit)
&& (MEM_read32(ip) == MEM_read32(ip - offset_2)) ) {
&& (MEM_read32(ip) == MEM_read32(ip - rep[1])) ) {
/* store sequence */
matchLength = ZSTD_count(ip+MINMATCH, ip+MINMATCH-offset_2, iend);
offset = offset_2;
offset_2 = offset_1;
offset_1 = offset;
matchLength = ZSTD_count(ip+MINMATCH, ip+MINMATCH-rep[1], iend);
offset = rep[1];
rep[1] = rep[0];
rep[0] = offset;
ZSTD_storeSeq(seqStorePtr, 0, anchor, 0 + ZSTD_REP_NUM - 1, matchLength);
ip += matchLength+MINMATCH;
anchor = ip;
@ -1719,7 +1728,6 @@ void ZSTD_compressBlock_lazy_extDict_generic(ZSTD_CCtx* ctx,
const BYTE* const dictEnd = dictBase + dictLimit;
const BYTE* const dictStart = dictBase + ctx->lowLimit;
size_t offset_2=REPCODE_STARTVALUE, offset_1=REPCODE_STARTVALUE;
const U32 maxSearches = 1 << ctx->params.searchLog;
const U32 mls = ctx->params.searchLength;
@ -1729,19 +1737,22 @@ void ZSTD_compressBlock_lazy_extDict_generic(ZSTD_CCtx* ctx,
searchMax_f searchMax = searchMethod ? ZSTD_BtFindBestMatch_selectMLS_extDict : ZSTD_HcFindBestMatch_extDict_selectMLS;
/* init */
U32 rep[ZSTD_REP_NUM];
for (int i=0; i<ZSTD_REP_NUM; i++)
rep[i]=REPCODE_STARTVALUE;
ZSTD_resetSeqStore(seqStorePtr);
if ((ip - prefixStart) < REPCODE_STARTVALUE) ip += REPCODE_STARTVALUE;
/* Match Loop */
while (ip < ilimit) {
size_t matchLength=0;
size_t offset=0;
size_t offset=(ZSTD_REP_NUM - 1);
const BYTE* start=ip+1;
U32 current = (U32)(ip-base);
/* check repCode */
{
const U32 repIndex = (U32)(current+1 - offset_1);
const U32 repIndex = (U32)(current+1 - rep[0]);
const BYTE* const repBase = repIndex < dictLimit ? dictBase : base;
const BYTE* const repMatch = repBase + repIndex;
if ((U32)((dictLimit-1) - repIndex) >= 3) /* intentional overflow */
@ -1757,7 +1768,7 @@ void ZSTD_compressBlock_lazy_extDict_generic(ZSTD_CCtx* ctx,
size_t offsetFound = 99999999;
size_t ml2 = searchMax(ctx, ip, iend, &offsetFound, maxSearches, mls);
if (ml2 > matchLength)
matchLength = ml2, start = ip, offset=offsetFound;
matchLength = ml2, start = ip, offset=offsetFound + (ZSTD_REP_NUM - 1);
}
if (matchLength < MINMATCH) {
@ -1771,8 +1782,8 @@ void ZSTD_compressBlock_lazy_extDict_generic(ZSTD_CCtx* ctx,
ip ++;
current++;
/* check repCode */
if (offset) {
const U32 repIndex = (U32)(current - offset_1);
if (offset >= ZSTD_REP_NUM) {
const U32 repIndex = (U32)(current - rep[0]);
const BYTE* const repBase = repIndex < dictLimit ? dictBase : base;
const BYTE* const repMatch = repBase + repIndex;
if ((U32)((dictLimit-1) - repIndex) >= 3) /* intentional overflow */
@ -1783,7 +1794,7 @@ void ZSTD_compressBlock_lazy_extDict_generic(ZSTD_CCtx* ctx,
int gain2 = (int)(repLength * 3);
int gain1 = (int)(matchLength*3 - ZSTD_highbit((U32)offset+1) + 1);
if ((repLength >= MINMATCH) && (gain2 > gain1))
matchLength = repLength, offset = 0, start = ip;
matchLength = repLength, offset = 0 + (ZSTD_REP_NUM - 1), start = ip;
} }
/* search match, depth 1 */
@ -1793,7 +1804,7 @@ void ZSTD_compressBlock_lazy_extDict_generic(ZSTD_CCtx* ctx,
int gain2 = (int)(ml2*4 - ZSTD_highbit((U32)offset2+1)); /* raw approx */
int gain1 = (int)(matchLength*4 - ZSTD_highbit((U32)offset+1) + 4);
if ((ml2 >= MINMATCH) && (gain2 > gain1)) {
matchLength = ml2, offset = offset2, start = ip;
matchLength = ml2, offset = offset2 + (ZSTD_REP_NUM - 1), start = ip;
continue; /* search a better one */
} }
@ -1802,8 +1813,8 @@ void ZSTD_compressBlock_lazy_extDict_generic(ZSTD_CCtx* ctx,
ip ++;
current++;
/* check repCode */
if (offset) {
const U32 repIndex = (U32)(current - offset_1);
if (offset >= ZSTD_REP_NUM) {
const U32 repIndex = (U32)(current - rep[0]);
const BYTE* const repBase = repIndex < dictLimit ? dictBase : base;
const BYTE* const repMatch = repBase + repIndex;
if ((U32)((dictLimit-1) - repIndex) >= 3) /* intentional overflow */
@ -1814,7 +1825,7 @@ void ZSTD_compressBlock_lazy_extDict_generic(ZSTD_CCtx* ctx,
int gain2 = (int)(repLength * 4);
int gain1 = (int)(matchLength*4 - ZSTD_highbit((U32)offset+1) + 1);
if ((repLength >= MINMATCH) && (gain2 > gain1))
matchLength = repLength, offset = 0, start = ip;
matchLength = repLength, offset = 0 + (ZSTD_REP_NUM - 1), start = ip;
} }
/* search match, depth 2 */
@ -1824,32 +1835,32 @@ void ZSTD_compressBlock_lazy_extDict_generic(ZSTD_CCtx* ctx,
int gain2 = (int)(ml2*4 - ZSTD_highbit((U32)offset2+1)); /* raw approx */
int gain1 = (int)(matchLength*4 - ZSTD_highbit((U32)offset+1) + 7);
if ((ml2 >= MINMATCH) && (gain2 > gain1)) {
matchLength = ml2, offset = offset2, start = ip;
matchLength = ml2, offset = offset2 + (ZSTD_REP_NUM - 1), start = ip;
continue;
} } }
break; /* nothing found : store previous solution */
}
/* catch up */
if (offset) {
U32 matchIndex = (U32)((start-base) - offset);
if (offset >= ZSTD_REP_NUM) {
U32 matchIndex = (U32)((start-base) - (offset - (ZSTD_REP_NUM - 1)));
const BYTE* match = (matchIndex < dictLimit) ? dictBase + matchIndex : base + matchIndex;
const BYTE* const mStart = (matchIndex < dictLimit) ? dictStart : prefixStart;
while ((start>anchor) && (match>mStart) && (start[-1] == match[-1])) { start--; match--; matchLength++; } /* catch up */
offset_2 = offset_1; offset_1 = offset;
rep[1] = rep[0]; rep[0] = offset - (ZSTD_REP_NUM - 1);
}
/* store sequence */
_storeSequence:
{
size_t litLength = start - anchor;
ZSTD_storeSeq(seqStorePtr, litLength, anchor, offset + ZSTD_REP_NUM - 1, matchLength-MINMATCH);
ZSTD_storeSeq(seqStorePtr, litLength, anchor, offset, matchLength-MINMATCH);
anchor = ip = start + matchLength;
}
/* check immediate repcode */
while (ip <= ilimit) {
const U32 repIndex = (U32)((ip-base) - offset_2);
const U32 repIndex = (U32)((ip-base) - rep[1]);
const BYTE* const repBase = repIndex < dictLimit ? dictBase : base;
const BYTE* const repMatch = repBase + repIndex;
if ((U32)((dictLimit-1) - repIndex) >= 3) /* intentional overflow */
@ -1857,7 +1868,7 @@ _storeSequence:
/* repcode detected we should take it */
const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend;
matchLength = ZSTD_count_2segments(ip+MINMATCH, repMatch+MINMATCH, iend, repEnd, prefixStart) + MINMATCH;
offset = offset_2; offset_2 = offset_1; offset_1 = offset; /* swap offset history */
offset = rep[1]; rep[1] = rep[0]; rep[0] = offset; /* swap offset history */
ZSTD_storeSeq(seqStorePtr, 0, anchor, 0 + ZSTD_REP_NUM - 1, matchLength-MINMATCH);
ip += matchLength;
anchor = ip;

49
lib/zstd_decompress.c
View File

@ -615,7 +615,7 @@ typedef struct {
FSE_DState_t stateLL;
FSE_DState_t stateOffb;
FSE_DState_t stateML;
size_t prevOffset;
size_t prevOffset[ZSTD_REP_NUM];
const BYTE* dumps;
const BYTE* dumpsEnd;
} seqState_t;
@ -633,7 +633,7 @@ static void ZSTD_decodeSequence(seq_t* seq, seqState_t* seqState, const U32 mls)
/* Literal length */
litLength = FSE_peakSymbol(&(seqState->stateLL));
prevOffset = litLength ? seq->offset : seqState->prevOffset;
prevOffset = litLength ? seq->offset : seqState->prevOffset[0];
if (litLength == MaxLL) {
U32 add = *dumps++;
if (add < 255) litLength += add;
@ -656,9 +656,45 @@ static void ZSTD_decodeSequence(seq_t* seq, seqState_t* seqState, const U32 mls)
if (offsetCode==0) nbBits = 0; /* cmove */
offset = offsetPrefix[offsetCode] + BIT_readBits(&(seqState->DStream), nbBits);
if (MEM_32bits()) BIT_reloadDStream(&(seqState->DStream));
if (offsetCode==0) offset = prevOffset; /* repcode, cmove */
else offset -= ZSTD_REP_NUM - 1;
if (offsetCode | !litLength) seqState->prevOffset = seq->offset; /* cmove */
if (offsetCode==0) {
/*
if (offset < LZMAX_NUM_REPS)
{
#if ZSTD_REP_NUM > 1
uint32_t pos = offset;
offset = reps[pos];
if (pos != 0)
{
if (pos != 1)
{
if (pos == 3)
reps[3] = reps[2];
reps[2] = reps[1];
}
reps[1] = reps[0];
reps[0] = offset;
}
#else
offset = reps[0];
#endif
}
else
{
#if ZSTD_REP_NUM > 1
offset -= LZMAX_NUM_REPS - 1;
reps[3] = reps[2];
reps[2] = reps[1];
reps[1] = reps[0];
#endif
reps[0] = offset;
}
*/
offset = prevOffset; /* repcode, cmove */
} else {
if (!litLength) seqState->prevOffset[0] = seq->offset; /* cmove */
offset -= ZSTD_REP_NUM - 1;
}
FSE_decodeSymbol(&(seqState->stateOffb), &(seqState->DStream)); /* update */
// printf("offsetCode=%d nbBits=%d offset=%d\n", offsetCode, nbBits, (int)offset); fflush(stdout);
}
@ -812,7 +848,8 @@ static size_t ZSTD_decompressSequences(
sequence.offset = REPCODE_STARTVALUE;
seqState.dumps = dumps;
seqState.dumpsEnd = dumps + dumpsLength;
seqState.prevOffset = REPCODE_STARTVALUE;
for (int i=0; i<ZSTD_REP_NUM; i++)
seqState.prevOffset[i] = REPCODE_STARTVALUE;
errorCode = BIT_initDStream(&(seqState.DStream), ip, iend-ip);
if (ERR_isError(errorCode)) return ERROR(corruption_detected);
FSE_initDState(&(seqState.stateLL), &(seqState.DStream), DTableLL);