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Adjustments to ldm_calculateMatchRange() to calculate bounds correctly

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This commit is contained in:
senhuang42 2020-09-30 19:45:40 -04:00
parent a1ef2db5b2
commit 7348b40a87
1 changed files with 8 additions and 8 deletions
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16
lib/compress/zstd_opt.c
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@ -799,29 +799,29 @@ static void ldm_calculateMatchRange(rawSeqStore_t* ldmSeqStore,
U32* matchOffset, U32 currPosInBlock,
U32 remainingBytes, U32 currBlockEndPos) {
rawSeq currSeq = ldmSeqStore->seq[ldmSeqStore->pos];
U32 blockPosInSequence = ldmSeqStore->posInSequence + currPosInBlock;
U32 literalsBytesLeft = blockPosInSequence < currSeq.litLength ?
currSeq.litLength - blockPosInSequence : 0;
/* In this case, the match is further in the block than currPosInBlock */
U32 literalsBytesLeft = (ldmSeqStore->posInSequence < currSeq.litLength) ?
currSeq.litLength - ldmSeqStore->posInSequence :
0;
/* In this case, the match is further in the block than currPosInBlock, and we are
currently in the literals section of the LDM */
if (literalsBytesLeft) {
if (literalsBytesLeft >= remainingBytes) {
/* If there are more literal bytes than bytes remaining in block, no ldm */
*matchStartPosInBlock = UINT_MAX;
*matchEndPosInBlock = UINT_MAX;
ldmSeqStore->pos++;
ldmSeqStore->posInSequence = 0;
ldm_moveForwardBytesInSeqStore(ldmSeqStore, remainingBytes);
return;
}
}
*matchStartPosInBlock = currPosInBlock + literalsBytesLeft;
*matchStartPosInBlock = currPosInBlock + currSeq.litLength;
*matchEndPosInBlock = *matchStartPosInBlock + currSeq.matchLength;
*matchOffset = currSeq.offset;
/* Match ends after the block ends, we can't use the whole match */
if (*matchEndPosInBlock > currBlockEndPos) {
*matchEndPosInBlock = currBlockEndPos;
ldmSeqStore->posInSequence += (currBlockEndPos - currPosInBlock);
ldm_moveForwardBytesInSeqStore(ldmSeqStore, currBlockEndPos - currPosInBlock);
} else {
/* We can use the entire match */
ldmSeqStore->posInSequence = 0;