ddidderr/zstd-rs
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Merge pull request #2376 from senhuang42/clarify_sequence_extraction_api

Browse Source 
Refine external ZSTD_Sequence API
This commit is contained in:
sen
2020-10-30 15:47:25 -04:00
committed by GitHub
parent ff93440fc6 f0da97642a
commit c37c714ef1
4 changed files with 90 additions and 50 deletions
Download Patch File Download Diff File Expand all files Collapse all files
lib/compress/zstd_compress.c
+33 -20
View File
@@ -2464,17 +2464,22 @@ static size_t ZSTD_buildSeqStore(ZSTD_CCtx* zc, const void* src, size_t srcSize)
static void ZSTD_copyBlockSequences(ZSTD_CCtx* zc)
{
const seqStore_t* seqStore = ZSTD_getSeqStore(zc);
const seqDef* seqs = seqStore->sequencesStart;
size_t seqsSize = seqStore->sequences - seqs;
const seqDef* seqStoreSeqs = seqStore->sequencesStart;
size_t seqStoreSeqSize = seqStore->sequences - seqStoreSeqs;
size_t seqStoreLiteralsSize = (size_t)(seqStore->lit - seqStore->litStart);
size_t literalsRead = 0;
size_t lastLLSize;
ZSTD_Sequence* outSeqs = &zc->seqCollector.seqStart[zc->seqCollector.seqIndex];
size_t i; size_t position; int repIdx;
size_t i;
int repIdx;
assert(zc->seqCollector.seqIndex + 1 < zc->seqCollector.maxSequences);
for (i = 0, position = 0; i < seqsSize; ++i) {
outSeqs[i].offset = seqs[i].offset;
outSeqs[i].litLength = seqs[i].litLength;
outSeqs[i].matchLength = seqs[i].matchLength + MINMATCH;
/* Ensure we have enough space for last literals "sequence" */
assert(zc->seqCollector.maxSequences >= seqStoreSeqSize + 1);
for (i = 0; i < seqStoreSeqSize; ++i) {
outSeqs[i].litLength = seqStoreSeqs[i].litLength;
outSeqs[i].matchLength = seqStoreSeqs[i].matchLength + MINMATCH;
if (i == seqStore->longLengthPos) {
if (seqStore->longLengthID == 1) {
@@ -2484,32 +2489,39 @@ static void ZSTD_copyBlockSequences(ZSTD_CCtx* zc)
}
}
if (outSeqs[i].offset <= ZSTD_REP_NUM) {
outSeqs[i].rep = outSeqs[i].offset;
repIdx = (unsigned int)i - outSeqs[i].offset;
if (seqStoreSeqs[i].offset <= ZSTD_REP_NUM) {
outSeqs[i].rep = seqStoreSeqs[i].offset;
repIdx = (unsigned int)i - seqStoreSeqs[i].offset;
if (outSeqs[i].litLength == 0) {
if (outSeqs[i].offset < 3) {
if (seqStoreSeqs[i].litLength == 0) {
if (seqStoreSeqs[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) {
if (outSeqs[i].rep == 3 && outSeqs[i].litLength == 0) {
--outSeqs[i].offset;
}
} else {
outSeqs[i].offset -= ZSTD_REP_NUM;
outSeqs[i].offset = seqStoreSeqs[i].offset - ZSTD_REP_NUM;
}
position += outSeqs[i].litLength;
outSeqs[i].matchPos = (unsigned int)position;
position += outSeqs[i].matchLength;
literalsRead += outSeqs[i].litLength;
}
zc->seqCollector.seqIndex += seqsSize;
/* 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.
*/
assert(seqStoreLiteralsSize >= literalsRead);
lastLLSize = seqStoreLiteralsSize - literalsRead;
outSeqs[i].litLength = (U32)lastLLSize;
outSeqs[i].matchLength = outSeqs[i].offset = outSeqs[i].rep = 0;
seqStoreSeqSize++;
zc->seqCollector.seqIndex += seqStoreSeqSize;
}
size_t ZSTD_getSequences(ZSTD_CCtx* zc, ZSTD_Sequence* outSeqs,
@@ -2584,6 +2596,7 @@ static size_t ZSTD_compressBlock_internal(ZSTD_CCtx* zc,
if (zc->seqCollector.collectSequences) {
ZSTD_copyBlockSequences(zc);
ZSTD_confirmRepcodesAndEntropyTables(zc);
return 0;
}