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ZSTD_estimateCStreamSize_advanced()

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This commit is contained in:
Yann Collet
2017-06-26 16:02:25 -07:00
parent 31af8290d1
commit 0c9a915a28
5 changed files with 21 additions and 9 deletions
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lib/compress/zstd_compress.c
+6 -1
View File
@@ -564,7 +564,7 @@ size_t ZSTD_estimateCCtxSize(int compressionLevel)
return ZSTD_estimateCCtxSize_advanced(cParams);
}
size_t ZSTD_estimateCStreamSize(ZSTD_compressionParameters cParams)
size_t ZSTD_estimateCStreamSize_advanced(ZSTD_compressionParameters cParams)
{
size_t const CCtxSize = ZSTD_estimateCCtxSize_advanced(cParams);
size_t const blockSize = MIN(ZSTD_BLOCKSIZE_MAX, (size_t)1 << cParams.windowLog);
@@ -575,6 +575,11 @@ size_t ZSTD_estimateCStreamSize(ZSTD_compressionParameters cParams)
return CCtxSize + streamingSize;
}
size_t ZSTD_estimateCStreamSize(int compressionLevel) {
ZSTD_compressionParameters const cParams = ZSTD_getCParams(compressionLevel, 0, 0);
return ZSTD_estimateCStreamSize_advanced(cParams);
}
static U32 ZSTD_equivalentParams(ZSTD_compressionParameters cParams1,
ZSTD_compressionParameters cParams2)
lib/zstd.h
+6 -2
View File
@@ -498,7 +498,7 @@ ZSTDLIB_API size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict);
* of a future {D,C}Ctx, before its creation.
* The objective is to guide decision before allocation.
* ZSTD_estimateCCtxSize() will consider src size to be arbitrarily "large".
* If srcSize is known to be small, ZSTD_estimateCCtxSize_advanced() will provide a better (smaller) estimation.
* If srcSize is known to be small, ZSTD_estimateCCtxSize_advanced() can provide a tighter estimation.
* ZSTD_estimateCCtxSize_advanced() can be used in tandem with ZSTD_getCParams() to create cParams from compressionLevel.
* Note : CCtx estimation is only correct for single-threaded compression */
ZSTDLIB_API size_t ZSTD_estimateCCtxSize(int compressionLevel);
@@ -506,10 +506,14 @@ ZSTDLIB_API size_t ZSTD_estimateCCtxSize_advanced(ZSTD_compressionParameters cPa
ZSTDLIB_API size_t ZSTD_estimateDCtxSize(void);
/*! ZSTD_estimate?StreamSize() :
* ZSTD_estimateCStreamSize() will consider src size to be arbitrarily "large".
* If srcSize is known to be small, ZSTD_estimateCStreamSize_advanced() can provide a tighter estimation.
* ZSTD_estimateCStreamSize_advanced() can be used in tandem with ZSTD_getCParams() to create cParams from compressionLevel.
* Note : if streaming is init with function ZSTD_init?Stream_usingDict(),
* an internal ?Dict will be created, which size is not estimated here.
* In this case, get total size by adding ZSTD_estimate?DictSize */
ZSTDLIB_API size_t ZSTD_estimateCStreamSize(ZSTD_compressionParameters cParams);
ZSTDLIB_API size_t ZSTD_estimateCStreamSize(int compressionLevel);
ZSTDLIB_API size_t ZSTD_estimateCStreamSize_advanced(ZSTD_compressionParameters cParams);
ZSTDLIB_API size_t ZSTD_estimateDStreamSize(ZSTD_frameHeader fHeader);
/*! ZSTD_estimate?DictSize() :