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Reduce number of memcpy() calls

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This commit is contained in:
senhuang42 2020-11-13 09:41:44 -05:00
parent be4ac6c5bc
commit 9d936d61d2
2 changed files with 10 additions and 12 deletions
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20
lib/compress/zstd_compress.c
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@ -2498,11 +2498,11 @@ static void ZSTD_copyBlockSequences(ZSTD_CCtx* zc)
ZSTD_Sequence* outSeqs = &zc->seqCollector.seqStart[zc->seqCollector.seqIndex];
size_t i;
repcodes_t updatedRepcodes;
U32* rep = zc->blockState.prevCBlock->rep;
assert(zc->seqCollector.seqIndex + 1 < zc->seqCollector.maxSequences);
/* Ensure we have enough space for last literals "sequence" */
assert(zc->seqCollector.maxSequences >= seqStoreSeqSize + 1);
ZSTD_memcpy(updatedRepcodes.rep, zc->blockState.prevCBlock->rep, sizeof(repcodes_t));
for (i = 0; i < seqStoreSeqSize; ++i) {
U32 rawOffset = seqStoreSeqs[i].offset - ZSTD_REP_NUM;
outSeqs[i].litLength = seqStoreSeqs[i].litLength;
@ -2521,22 +2521,23 @@ static void ZSTD_copyBlockSequences(ZSTD_CCtx* zc)
/* Derive the correct offset corresponding to a repcode */
outSeqs[i].rep = seqStoreSeqs[i].offset;
if (outSeqs[i].litLength != 0) {
rawOffset = rep[outSeqs[i].rep - 1];
rawOffset = updatedRepcodes.rep[outSeqs[i].rep - 1];
} else {
if (outSeqs[i].rep == 3) {
rawOffset = rep[0] - 1;
rawOffset = updatedRepcodes.rep[0] - 1;
} else {
rawOffset = rep[outSeqs[i].rep];
rawOffset = updatedRepcodes.rep[outSeqs[i].rep];
}
}
}
outSeqs[i].offset = rawOffset;
updatedRepcodes = ZSTD_updateRep(rep, seqStoreSeqs[i].offset - 1, seqStoreSeqs[i].litLength == 0);
ZSTD_memcpy(rep, updatedRepcodes.rep, sizeof(repcodes_t));
/* seqStoreSeqs[i].offset == offCode+1, and ZSTD_updateRep() expects offCode
so we provide seqStoreSeqs[i].offset - 1 */
updatedRepcodes = ZSTD_updateRep(updatedRepcodes.rep,
seqStoreSeqs[i].offset - 1,
seqStoreSeqs[i].litLength == 0);
literalsRead += outSeqs[i].litLength;
}
/* Insert last literals (if any exist) in the block as a sequence with ml == off == 0.
* If there are no last literals, then we'll emit (of: 0, ml: 0, ll: 0), which is a marker
* for the block boundary, according to the API.
@ -2546,9 +2547,6 @@ static void ZSTD_copyBlockSequences(ZSTD_CCtx* zc)
outSeqs[i].litLength = (U32)lastLLSize;
outSeqs[i].matchLength = outSeqs[i].offset = outSeqs[i].rep = 0;
seqStoreSeqSize++;
ZSTD_memcpy(zc->blockState.nextCBlock->rep, zc->blockState.prevCBlock->rep,
sizeof(zc->blockState.nextCBlock->rep));
zc->seqCollector.seqIndex += seqStoreSeqSize;
}

2
tests/fuzzer.c
View File

@ -2721,7 +2721,7 @@ static int basicUnitTests(U32 const seed, double compressibility)
if (seqs == NULL) goto _output_error;
assert(cctx != NULL);
ZSTD_CCtx_setParameter(cctx, ZSTD_c_compressionLevel, 19);
/* Populate src with random data */
RDG_genBuffer(CNBuffer, srcSize, compressibility, 0.5, seed);