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updated ZSTD_estimateCCtxSize()

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added a parameter streaming,
to estimate memory allocation size
when the CCtx is used for streaming (CStream).

Note : this function is not able to estimate
memory cost of a potential internal CDict
which can only happen when starting with ZSTD_initCStream_usingDict()
This commit is contained in:
Yann Collet
2017-05-08 17:07:59 -07:00
parent 791d744279
commit fc5145955a
4 changed files with 24 additions and 17 deletions
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lib/zstd.h
+5 -3
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@@ -460,8 +460,10 @@ ZSTDLIB_API unsigned long long ZSTD_findDecompressedSize(const void* src, size_t
***************************************/
/*! ZSTD_estimateCCtxSize() :
* Gives the amount of memory allocated for a ZSTD_CCtx given a set of compression parameters.
* `frameContentSize` is an optional parameter, provide `0` if unknown */
ZSTDLIB_API size_t ZSTD_estimateCCtxSize(ZSTD_compressionParameters cParams);
* 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 */
@@ -599,7 +601,7 @@ ZSTDLIB_API unsigned ZSTD_getDictID_fromFrame(const void* src, size_t srcSize);
ZSTDLIB_API ZSTD_CStream* ZSTD_createCStream_advanced(ZSTD_customMem customMem);
ZSTDLIB_API size_t ZSTD_sizeof_CStream(const ZSTD_CStream* zcs); /**< same as ZSTD_sizeof_CCtx */
ZSTDLIB_API size_t ZSTD_initCStream_srcSize(ZSTD_CStream* zcs, int compressionLevel, unsigned long long pledgedSrcSize); /**< pledgedSrcSize must be correct, a size of 0 means unknown. for a frame size of 0 use initCStream_advanced */
ZSTDLIB_API size_t ZSTD_initCStream_usingDict(ZSTD_CStream* zcs, const void* dict, size_t dictSize, int compressionLevel); /**< note: a dict will not be used if dict == NULL or dictSize < 8 */
ZSTDLIB_API size_t ZSTD_initCStream_usingDict(ZSTD_CStream* zcs, const void* dict, size_t dictSize, int compressionLevel); /**< note: a dict will not be used if dict == NULL or dictSize < 8. This result in the creation of an internal CDict */
ZSTDLIB_API size_t ZSTD_initCStream_advanced(ZSTD_CStream* zcs, const void* dict, size_t dictSize,
ZSTD_parameters params, unsigned long long pledgedSrcSize); /**< pledgedSrcSize is optional and can be 0 (meaning unknown). note: if the contentSizeFlag is set, pledgedSrcSize == 0 means the source size is actually 0 */
ZSTDLIB_API size_t ZSTD_initCStream_usingCDict(ZSTD_CStream* zcs, const ZSTD_CDict* cdict); /**< note : cdict will just be referenced, and must outlive compression session */