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Merge pull request #2381 from senhuang42/expand_sequence_extraction_api

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Add enum to define ZSTD_Sequence type and update sequence extraction API
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sen
2020-11-06 13:00:31 -05:00
committed by GitHub
parent 07ee8bfe33 7d1dea070c
commit f62edf0fe9
3 changed files with 62 additions and 16 deletions
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lib/zstd.h
+26 -7
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@@ -1149,7 +1149,7 @@ typedef struct {
* rep == 2 --> offset == repeat_offset_3
* rep == 3 --> offset == repeat_offset_1 - 1
*
* Note: This field is optional. ZSTD_getSequences() will calculate the value of
* Note: This field is optional. ZSTD_generateSequences() will calculate the value of
* 'rep', but repeat offsets do not necessarily need to be calculated from an external
* sequence provider's perspective.
*/
@@ -1297,17 +1297,36 @@ ZSTDLIB_API unsigned long long ZSTD_decompressBound(const void* src, size_t srcS
* or an error code (if srcSize is too small) */
ZSTDLIB_API size_t ZSTD_frameHeaderSize(const void* src, size_t srcSize);
/*! ZSTD_getSequences() :
* Extract sequences from the sequence store.
* Each block will end with a dummy sequence with offset == 0, matchLength == 0, and litLength == length of last literals.
typedef enum {
ZSTD_sf_explicitBlockDelimiters, /* Representation of ZSTD_Sequence contains explicit block delimiters */
ZSTD_sf_noBlockDelimiters /* Representation of ZSTD_Sequence has no block delimiters, sequences only */
} ZSTD_sequenceFormat_e;
/*! ZSTD_generateSequences() :
* Generate sequences using ZSTD_compress2, given a source buffer.
*
* Each block will end with a dummy sequence
* with offset == 0, matchLength == 0, and litLength == length of last literals.
* litLength may be == 0, and if so, then the sequence of (of: 0 ml: 0 ll: 0)
* simply acts as a block delimiter.
*
* zc can be used to insert custom compression params.
* This function invokes ZSTD_compress2
* @return : number of sequences extracted
* @return : number of sequences generated
*/
ZSTDLIB_API size_t ZSTD_getSequences(ZSTD_CCtx* zc, ZSTD_Sequence* outSeqs,
size_t outSeqsSize, const void* src, size_t srcSize);
ZSTDLIB_API size_t ZSTD_generateSequences(ZSTD_CCtx* zc, ZSTD_Sequence* outSeqs,
size_t outSeqsSize, const void* src, size_t srcSize);
/*! ZSTD_mergeBlockDelimiters() :
* Given an array of ZSTD_Sequence, remove all sequences that represent block delimiters/last literals
* by merging them into into the literals of the next sequence.
*
* As such, the final generated result has no explicit representation of block boundaries,
* and the final last literals segment is not represented in the sequences.
* @return : number of sequences left after merging
*/
ZSTDLIB_API size_t ZSTD_mergeBlockDelimiters(ZSTD_Sequence* sequences, size_t seqsSize);
/***************************************
* Memory management