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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 10:41:09 -07:00
parent f8ac0ea7ef
commit b1a43455f8
3 changed files with 26 additions and 19 deletions
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lib/common/zstd_internal.h
+13 -6
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@@ -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;
}
}