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Add enum for representing long length ID

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This commit is contained in:
Sen Huang 2021-03-26 10:35:52 -07:00
parent f8ac0ea7ef
commit b1a43455f8
3 changed files with 26 additions and 19 deletions
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19
lib/common/zstd_internal.h
View File

@ -357,6 +357,13 @@ typedef struct seqDef_s {
U16 matchLength;
} seqDef;
/* Controls whether seqStore has a single "long" litLength or matchLength. See seqStore_t. */
typedef enum {
ZSTD_llt_none = 0, /* no longLengthType */
ZSTD_llt_literalLength = 1, /* represents a long literal */
ZSTD_llt_matchLength = 2 /* represents a long match */
} ZSTD_longLengthType_e;
typedef struct {
seqDef* sequencesStart;
seqDef* sequences; /* ptr to end of sequences */
@ -368,12 +375,12 @@ typedef struct {
size_t maxNbSeq;
size_t maxNbLit;
/* longLengthPos and longLengthID to allow us to represent either a single litLength or matchLength
/* longLengthPos and longLengthType to allow us to represent either a single litLength or matchLength
* in the seqStore that has a value larger than U16 (if it exists). To do so, we increment
* the existing value of the litLength or matchLength by 0x10000.
*/
U32 longLengthID; /* 0 == no longLength; 1 == Represent the long literal; 2 == Represent the long match; */
U32 longLengthPos; /* Index of the sequence to apply long length modification to */
ZSTD_longLengthType_e longLengthType;
U32 longLengthPos; /* Index of the sequence to apply long length modification to */
} seqStore_t;
typedef struct {
@ -383,7 +390,7 @@ typedef struct {
/**
* Returns the ZSTD_sequenceLength for the given sequences. It handles the decoding of long sequences
* indicated by longLengthPos and longLengthID, and adds MINMATCH back to matchLength.
* indicated by longLengthPos and longLengthType, and adds MINMATCH back to matchLength.
*/
MEM_STATIC ZSTD_sequenceLength ZSTD_getSequenceLength(seqStore_t const* seqStore, seqDef const* seq)
{
@ -391,10 +398,10 @@ MEM_STATIC ZSTD_sequenceLength ZSTD_getSequenceLength(seqStore_t const* seqStore
seqLen.litLength = seq->litLength;
seqLen.matchLength = seq->matchLength + MINMATCH;
if (seqStore->longLengthPos == (U32)(seq - seqStore->sequencesStart)) {
if (seqStore->longLengthID == 1) {
if (seqStore->longLengthType == ZSTD_llt_literalLength) {
seqLen.litLength += 0xFFFF;
}
if (seqStore->longLengthID == 2) {
if (seqStore->longLengthType == ZSTD_llt_matchLength) {
seqLen.matchLength += 0xFFFF;
}
}

18
lib/compress/zstd_compress.c
View File

@ -2197,9 +2197,9 @@ void ZSTD_seqToCodes(const seqStore_t* seqStorePtr)
ofCodeTable[u] = (BYTE)ZSTD_highbit32(sequences[u].offset);
mlCodeTable[u] = (BYTE)ZSTD_MLcode(mlv);
}
if (seqStorePtr->longLengthID==1)
if (seqStorePtr->longLengthType==ZSTD_llt_literalLength)
llCodeTable[seqStorePtr->longLengthPos] = MaxLL;
if (seqStorePtr->longLengthID==2)
if (seqStorePtr->longLengthType==ZSTD_llt_matchLength)
mlCodeTable[seqStorePtr->longLengthPos] = MaxML;
}
@ -2571,7 +2571,7 @@ void ZSTD_resetSeqStore(seqStore_t* ssPtr)
{
ssPtr->lit = ssPtr->litStart;
ssPtr->sequences = ssPtr->sequencesStart;
ssPtr->longLengthID = 0;
ssPtr->longLengthType = ZSTD_llt_none;
}
typedef enum { ZSTDbss_compress, ZSTDbss_noCompress } ZSTD_buildSeqStore_e;
@ -2677,9 +2677,9 @@ static void ZSTD_copyBlockSequences(ZSTD_CCtx* zc)
outSeqs[i].rep = 0;
if (i == seqStore->longLengthPos) {
if (seqStore->longLengthID == 1) {
if (seqStore->longLengthType == ZSTD_llt_literalLength) {
outSeqs[i].litLength += 0x10000;
} else if (seqStore->longLengthID == 2) {
} else if (seqStore->longLengthType == ZSTD_llt_matchLength) {
outSeqs[i].matchLength += 0x10000;
}
}
@ -3116,7 +3116,7 @@ static size_t ZSTD_countSeqStoreLiteralsBytes(const seqStore_t* const seqStore)
for (i = 0; i < nbSeqs; ++i) {
seqDef seq = seqStore->sequencesStart[i];
literalsBytes += seq.litLength;
if (i == seqStore->longLengthPos && seqStore->longLengthID == 1) {
if (i == seqStore->longLengthPos && seqStore->longLengthType == ZSTD_llt_literalLength) {
literalsBytes += 0x10000;
}
}
@ -3131,7 +3131,7 @@ static size_t ZSTD_countSeqStoreMatchBytes(const seqStore_t* const seqStore) {
for (i = 0; i < nbSeqs; ++i) {
seqDef seq = seqStore->sequencesStart[i];
matchBytes += seq.matchLength + MINMATCH;
if (i == seqStore->longLengthPos && seqStore->longLengthID == 2) {
if (i == seqStore->longLengthPos && seqStore->longLengthType == ZSTD_llt_matchLength) {
matchBytes += 0x10000;
}
}
@ -3155,9 +3155,9 @@ static void ZSTD_deriveSeqStoreChunk(seqStore_t* resultSeqStore,
}
/* Move longLengthPos into the correct position if necessary */
if (originalSeqStore->longLengthID != 0) {
if (originalSeqStore->longLengthType != ZSTD_llt_none) {
if (originalSeqStore->longLengthPos < startIdx || originalSeqStore->longLengthPos > endIdx) {
resultSeqStore->longLengthID = 0;
resultSeqStore->longLengthType = ZSTD_llt_none;
} else {
resultSeqStore->longLengthPos -= (U32)startIdx;
}

8
lib/compress/zstd_compress_internal.h
View File

@ -597,8 +597,8 @@ void ZSTD_storeSeq(seqStore_t* seqStorePtr, size_t litLength, const BYTE* litera
/* literal Length */
if (litLength>0xFFFF) {
assert(seqStorePtr->longLengthID == 0); /* there can only be a single long length */
seqStorePtr->longLengthID = 1;
assert(seqStorePtr->longLengthType == ZSTD_llt_none); /* there can only be a single long length */
seqStorePtr->longLengthType = ZSTD_llt_literalLength;
seqStorePtr->longLengthPos = (U32)(seqStorePtr->sequences - seqStorePtr->sequencesStart);
}
seqStorePtr->sequences[0].litLength = (U16)litLength;
@ -608,8 +608,8 @@ void ZSTD_storeSeq(seqStore_t* seqStorePtr, size_t litLength, const BYTE* litera
/* match Length */
if (mlBase>0xFFFF) {
assert(seqStorePtr->longLengthID == 0); /* there can only be a single long length */
seqStorePtr->longLengthID = 2;
assert(seqStorePtr->longLengthType == ZSTD_llt_none); /* there can only be a single long length */
seqStorePtr->longLengthType = ZSTD_llt_matchLength;
seqStorePtr->longLengthPos = (U32)(seqStorePtr->sequences - seqStorePtr->sequencesStart);
}
seqStorePtr->sequences[0].matchLength = (U16)mlBase;