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

added constant ZSTD_MAGIC_SKIPPABLE_MASK

Browse Source 
and updated several API comments
This commit is contained in:
Yann Collet
2018-11-13 17:36:35 -08:00
parent b83d1e7714
commit 2c8fde538f
4 changed files with 106 additions and 63 deletions
Download Patch File Download Diff File Expand all files Collapse all files
lib/zstd.h
+46 -19
View File
@@ -415,9 +415,12 @@ ZSTDLIB_API size_t ZSTD_DStreamOutSize(void); /*!< recommended size for output
ZSTDLIB_API int ZSTD_minCLevel(void); /*!< minimum negative compression level allowed */
/* --- Constants ---*/
#define ZSTD_MAGICNUMBER 0xFD2FB528 /* v0.8+ */
#define ZSTD_MAGIC_DICTIONARY 0xEC30A437 /* v0.7+ */
#define ZSTD_MAGIC_SKIPPABLE_START 0x184D2A50U
/* all magic numbers are supposed read/written to/from files/memory using little-endian convention */
#define ZSTD_MAGICNUMBER 0xFD2FB528 /* valid since v0.8.0 */
#define ZSTD_MAGIC_DICTIONARY 0xEC30A437 /* valid since v0.7.0 */
#define ZSTD_MAGIC_SKIPPABLE_START 0x184D2A50 /* all 16 values, from 0x184D2A50 to 0x184D2A5F, are understood as skippable frames */
#define ZSTD_MAGIC_SKIPPABLE_MASK 0xFFFFFFF0
#define ZSTD_BLOCKSIZELOG_MAX 17
#define ZSTD_BLOCKSIZE_MAX (1<<ZSTD_BLOCKSIZELOG_MAX) /* define, for static allocation */
@@ -439,6 +442,20 @@ ZSTDLIB_API int ZSTD_minCLevel(void); /*!< minimum negative compression level a
#define ZSTD_SEARCHLENGTH_MIN 3 /* only for ZSTD_btopt, other strategies are limited to 4 */
#define ZSTD_TARGETLENGTH_MAX ZSTD_BLOCKSIZE_MAX
#define ZSTD_TARGETLENGTH_MIN 0 /* note : comparing this constant to an unsigned results in a tautological test */
/****************************************************************************************
* Purely experimental API
****************************************************************************************
* The following symbols and constants are not planned
* to join "stable API" status anytime soon.
* Some of them might even be removed in the future.
* ***************************************************************************************/
#define ZSTD_LDM_MINMATCH_MAX 4096
#define ZSTD_LDM_MINMATCH_MIN 4
#define ZSTD_LDM_BUCKETSIZELOG_MAX 8
@@ -450,23 +467,33 @@ ZSTDLIB_API int ZSTD_minCLevel(void); /*!< minimum negative compression level a
/* --- Advanced types --- */
typedef enum { ZSTD_fast=1, ZSTD_dfast, ZSTD_greedy, ZSTD_lazy, ZSTD_lazy2,
ZSTD_btlazy2, ZSTD_btopt, ZSTD_btultra } ZSTD_strategy; /* from faster to stronger */
/* Compression strategies, listed from fastest to strongest */
typedef enum { ZSTD_fast=1,
ZSTD_dfast=2,
ZSTD_greedy=3,
ZSTD_lazy=4,
ZSTD_lazy2=5,
ZSTD_btlazy2=6,
ZSTD_btopt=7,
ZSTD_btultra=8
/* note : new strategies might be added in the future */
} ZSTD_strategy;
typedef struct {
unsigned windowLog; /**< largest match distance : larger == more compression, more memory needed during decompression */
unsigned chainLog; /**< fully searched segment : larger == more compression, slower, more memory (useless for fast) */
unsigned hashLog; /**< dispatch table : larger == faster, more memory */
unsigned searchLog; /**< nb of searches : larger == more compression, slower */
unsigned searchLength; /**< match length searched : larger == faster decompression, sometimes less compression */
unsigned targetLength; /**< acceptable match size for optimal parser (only) : larger == more compression, slower */
ZSTD_strategy strategy;
unsigned windowLog; /**< largest match distance : larger == more compression, more memory needed during decompression */
unsigned chainLog; /**< fully searched segment : larger == more compression, slower, more memory (useless for fast) */
unsigned hashLog; /**< dispatch table : larger == faster, more memory */
unsigned searchLog; /**< nb of searches : larger == more compression, slower */
unsigned searchLength; /**< match length searched : larger == faster decompression, sometimes less compression */
unsigned targetLength; /**< acceptable match size for optimal parser (only) : larger == more compression, slower */
ZSTD_strategy strategy; /**< see ZSTD_strategy definition above */
} ZSTD_compressionParameters;
typedef struct {
unsigned contentSizeFlag; /**< 1: content size will be in frame header (when known) */
unsigned checksumFlag; /**< 1: generate a 32-bits checksum at end of frame, for error detection */
unsigned noDictIDFlag; /**< 1: no dictID will be saved into frame header (if dictionary compression) */
unsigned checksumFlag; /**< 1: generate a 32-bits checksum using XXH64 algorithm at end of frame, for error detection */
unsigned noDictIDFlag; /**< 1: no dictID will be saved into frame header (dictID is only useful for dictionary compression) */
} ZSTD_frameParameters;
typedef struct {
@@ -477,14 +504,14 @@ typedef struct {
typedef struct ZSTD_CCtx_params_s ZSTD_CCtx_params;
typedef enum {
ZSTD_dct_auto = 0, /* dictionary is "full" when starting with ZSTD_MAGIC_DICTIONARY, otherwise it is "rawContent" */
ZSTD_dct_rawContent, /* ensures dictionary is always loaded as rawContent, even if it starts with ZSTD_MAGIC_DICTIONARY */
ZSTD_dct_fullDict /* refuses to load a dictionary if it does not respect Zstandard's specification */
ZSTD_dct_auto = 0, /* dictionary is "full" when starting with ZSTD_MAGIC_DICTIONARY, otherwise it is "rawContent" */
ZSTD_dct_rawContent = 1, /* ensures dictionary is always loaded as rawContent, even if it starts with ZSTD_MAGIC_DICTIONARY */
ZSTD_dct_fullDict = 2 /* refuses to load a dictionary if it does not respect Zstandard's specification, starting with ZSTD_MAGIC_DICTIONARY */
} ZSTD_dictContentType_e;
typedef enum {
ZSTD_dlm_byCopy = 0, /**< Copy dictionary content internally */
ZSTD_dlm_byRef, /**< Reference dictionary content -- the dictionary buffer must outlive its users. */
ZSTD_dlm_byCopy = 0, /**< Copy dictionary content internally */
ZSTD_dlm_byRef = 1, /**< Reference dictionary content -- the dictionary buffer must outlive its users. */
} ZSTD_dictLoadMethod_e;