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added ZSTD_estimateCDictSize() and ZSTD_estimateDDictSize()

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it complements ZSTD_estimateCCtxSize()
for the special case of ZSTD_initCStream_usingDict()
This commit is contained in:
Yann Collet
2017-05-08 17:51:49 -07:00
parent 7855366598
commit a1d6704d7f
5 changed files with 57 additions and 13 deletions
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lib/zstd.h
+17 -7
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@@ -458,17 +458,17 @@ ZSTDLIB_API unsigned long long ZSTD_findDecompressedSize(const void* src, size_t
/***************************************
* Advanced compression functions
***************************************/
/*! ZSTD_estimateCCtxSize() :
* Gives the amount of memory allocated for a ZSTD_CCtx given a set of compression parameters.
* Set streaming to 1 if the CCtx will be used for streaming (CStream)
* Note : this function is currently unable to estimate additional memory allocation needed to create an internal CDict
* which can only happen when starting with ZSTD_initCStream_usingDict() */
ZSTDLIB_API size_t ZSTD_estimateCCtxSize(ZSTD_compressionParameters cParams, unsigned streaming);
/*! ZSTD_createCCtx_advanced() :
* Create a ZSTD compression context using external alloc and free functions */
ZSTDLIB_API ZSTD_CCtx* ZSTD_createCCtx_advanced(ZSTD_customMem customMem);
/*! ZSTD_estimateCCtxSize() :
* Provides amount of memory needed to allocate ZSTD_CCtx with a set of compression parameters.
* Set streaming to 1 if the CCtx will be used for streaming (CStream).
* Special case : when using ZSTD_initCStream_usingDict(), init will transparently create an internal CDict.
* Use ZSTD_estimateCDictSize() and add this value to estimate total CCtx size */
ZSTDLIB_API size_t ZSTD_estimateCCtxSize(ZSTD_compressionParameters cParams, unsigned streaming);
/*! ZSTD_sizeofCCtx() :
* amount of used memory is variable, depending primarily on compression level */
ZSTDLIB_API size_t ZSTD_sizeof_CCtx(const ZSTD_CCtx* cctx);
@@ -493,6 +493,11 @@ ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict_byReference(const void* dictBuffer, siz
ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict_advanced(const void* dict, size_t dictSize, unsigned byReference,
ZSTD_compressionParameters cParams, ZSTD_customMem customMem);
/*! ZSTD_estimateCDictSize() :
* Estimate amount of memory that will be needed to create a dictionary with following arguments
* Note : if dictionary is created "byReference", reduce this amount by dictSize */
ZSTDLIB_API size_t ZSTD_estimateCDictSize(ZSTD_compressionParameters cParams, size_t dictSize);
/*! ZSTD_sizeof_CDict() :
* Gives the amount of memory used by a given ZSTD_sizeof_CDict */
ZSTDLIB_API size_t ZSTD_sizeof_CDict(const ZSTD_CDict* cdict);
@@ -564,6 +569,11 @@ ZSTDLIB_API ZSTD_DDict* ZSTD_createDDict_byReference(const void* dictBuffer, siz
ZSTDLIB_API ZSTD_DDict* ZSTD_createDDict_advanced(const void* dict, size_t dictSize,
unsigned byReference, ZSTD_customMem customMem);
/*! ZSTD_estimateDDictSize() :
* Estimate amount of memory that will be needed to create a dictionary for decompression.
* Note : if dictionary is created "byReference", reduce this amount by dictSize */
ZSTDLIB_API size_t ZSTD_estimateDDictSize(size_t dictSize);
/*! ZSTD_sizeof_DDict() :
* Gives the amount of memory used by a given ZSTD_DDict */
ZSTDLIB_API size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict);