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Cleaning sequence parsing logic

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This commit is contained in:
Bimba Shrestha 2019-10-03 06:42:40 -07:00
parent b63a1e7ae5
commit 61ec4c2e7f
1 changed files with 25 additions and 34 deletions
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59
lib/compress/zstd_compress.c
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@ -2272,46 +2272,37 @@ static void ZSTD_copyBlockSequences(ZSTD_CCtx* zc)
size_t seqsSize = seqStore->sequences - seqs;
ZSTD_Sequence* outSeqs = &zc->seqCollector.seqStart[zc->seqCollector.seqIndex];
size_t i; size_t position; int repIdx;
int i;
assert(zc->seqCollector.seqIndex + 1 < zc->seqCollector.maxSequences);
for (i = 0, position = 0; i < seqsSize; ++i) {
outSeqs[i].offset = seqs[i].offset;
for (i = 0; i < (int)seqsSize; ++i) {
unsigned int offsetValue = seqs[i].offset;
outSeqs[i].litLength = seqs[i].litLength;
outSeqs[i].matchLength = seqs[i].matchLength + MINMATCH;
if (i == seqStore->longLengthPos) {
if (seqStore->longLengthID == 1) {
outSeqs[i].litLength += 0x10000;
} else if (seqStore->longLengthID == 2) {
outSeqs[i].matchLength += 0x10000;
}
}
if (outSeqs[i].offset <= ZSTD_REP_NUM) {
outSeqs[i].rep = outSeqs[i].offset;
repIdx = (unsigned int)i - outSeqs[i].offset;
if (outSeqs[i].litLength == 0) {
if (outSeqs[i].offset < 3) {
--repIdx;
} else {
repIdx = (unsigned int)i - 1;
}
++outSeqs[i].rep;
}
assert(repIdx >= -3);
outSeqs[i].offset = repIdx >= 0 ? outSeqs[repIdx].offset : repStartValue[-repIdx - 1];
if (outSeqs[i].rep == 4) {
--outSeqs[i].offset;
}
outSeqs[i].matchLength = seqs[i].matchLength;
if (offsetValue > 3) {
outSeqs[i].offset = offsetValue - 3;
} else {
outSeqs[i].offset -= ZSTD_REP_NUM;
/* special repeat offset case */
unsigned int repeatOffset1 = i - 1 >= 0 ? outSeqs[i - 1].offset : 1;
unsigned int repeatOffset2 = 1 - 2 >= 0 ? outSeqs[i - 2].offset : 4;
unsigned int repeatOffset3 = i - 3 >= 0 ? outSeqs[i - 3].offset : 8;
if (seqs[i].litLength != 0) {
switch (offsetValue) {
case 1: outSeqs[i].offset = repeatOffset1; break;
case 2: outSeqs[i].offset = repeatOffset2; break;
case 3: outSeqs[i].offset = repeatOffset3; break;
}
} else {
/* offsets shifted by one */
switch (offsetValue) {
case 1: outSeqs[i].offset = repeatOffset2; break;
case 2: outSeqs[i].offset = repeatOffset3; break;
/* corner case where offsetValue == 3 */
case 3: outSeqs[i].offset = repeatOffset1 - 1; break;
}
}
}
position += outSeqs[i].litLength;
outSeqs[i].matchPos = (unsigned int)position;
position += outSeqs[i].matchLength;
}
zc->seqCollector.seqIndex += seqsSize;
}