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exposed ZSTD_MAGIC_DICTIONARY in zstd.h

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makes it easier to explain ZSTD_dictMode
This commit is contained in:
Yann Collet
2017-06-27 13:50:34 -07:00
parent fecc721fd9
commit 7d3816183f
6 changed files with 20 additions and 14 deletions
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lib/zstd.h
+7 -3
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@@ -360,6 +360,7 @@ ZSTDLIB_API size_t ZSTD_DStreamOutSize(void); /*!< recommended size for output
/* --- Constants ---*/
#define ZSTD_MAGICNUMBER 0xFD2FB528 /* >= v0.8.0 */
#define ZSTD_MAGIC_SKIPPABLE_START 0x184D2A50U
#define ZSTD_MAGIC_DICTIONARY 0xEC30A437 /* v0.7+ */
#define ZSTD_WINDOWLOG_MAX_32 27
#define ZSTD_WINDOWLOG_MAX_64 27
@@ -379,7 +380,7 @@ ZSTDLIB_API size_t ZSTD_DStreamOutSize(void); /*!< recommended size for output
#define ZSTD_FRAMEHEADERSIZE_MAX 18 /* for static allocation */
#define ZSTD_FRAMEHEADERSIZE_MIN 6
static const size_t ZSTD_frameHeaderSize_prefix = 5;
static const size_t ZSTD_frameHeaderSize_prefix = 5; /* minimum input size to know frame header size */
static const size_t ZSTD_frameHeaderSize_min = ZSTD_FRAMEHEADERSIZE_MIN;
static const size_t ZSTD_frameHeaderSize_max = ZSTD_FRAMEHEADERSIZE_MAX;
static const size_t ZSTD_skippableHeaderSize = 8; /* magic number + skippable frame length */
@@ -573,7 +574,10 @@ ZSTDLIB_API size_t ZSTD_setCCtxParameter(ZSTD_CCtx* cctx, ZSTD_CCtxParameter par
ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict_byReference(const void* dictBuffer, size_t dictSize, int compressionLevel);
typedef enum { ZSTD_dm_auto=0, ZSTD_dm_rawContent, ZSTD_dm_fullDict } ZSTD_dictMode_e;
typedef enum { ZSTD_dm_auto=0, /* dictionary is "full" if it starts with ZSTD_MAGIC_DICTIONARY, rawContent otherwize */
ZSTD_dm_rawContent, /* ensures dictionary is always loaded as rawContent, even if it starts with ZSTD_MAGIC_DICTIONARY */
ZSTD_dm_fullDict /* refuses to load a dictionary if it does not respect Zstandard's specification */
} ZSTD_dictMode_e;
/*! ZSTD_createCDict_advanced() :
* Create a ZSTD_CDict using external alloc and free, and customized compression parameters */
ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict_advanced(const void* dict, size_t dictSize,
@@ -1027,7 +1031,7 @@ ZSTDLIB_API size_t ZSTD_CCtx_loadDictionary(ZSTD_CCtx* cctx, const void* dict, s
ZSTDLIB_API size_t ZSTD_CCtx_refCDict(ZSTD_CCtx* cctx, const ZSTD_CDict* cdict);
/*! ZSTD_CCtx_refPrefix() :
* Reference a prefix (content-only dictionary) to bootstrap next compression job.
* Reference a prefix (raw-content dictionary) for next compression job.
* Decompression will have to use same prefix.
* Prefix is only used once. Tables are discarded at end of compression job.
* If there is a need to use same prefix multiple times, consider embedding it into a ZSTD_CDict.