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@@ -5,6 +5,7 @@
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* This source code is licensed under both the BSD-style license (found in the
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* LICENSE file in the root directory of this source tree) and the GPLv2 (found
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* in the COPYING file in the root directory of this source tree).
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+ * You may select, at your option, one of the above-listed licenses.
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*/
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#if defined (__cplusplus)
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extern "C" {
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@@ -58,7 +59,7 @@ extern "C" {
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/*------ Version ------*/
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#define ZSTD_VERSION_MAJOR 1
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#define ZSTD_VERSION_MINOR 3
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-#define ZSTD_VERSION_RELEASE 1
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+#define ZSTD_VERSION_RELEASE 2
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#define ZSTD_VERSION_NUMBER (ZSTD_VERSION_MAJOR *100*100 + ZSTD_VERSION_MINOR *100 + ZSTD_VERSION_RELEASE)
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ZSTDLIB_API unsigned ZSTD_versionNumber(void); /**< useful to check dll version */
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@@ -130,10 +131,11 @@ ZSTDLIB_API unsigned long long ZSTD_getDecompressedSize(const void* src, size_t
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/*====== Helper functions ======*/
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-ZSTDLIB_API int ZSTD_maxCLevel(void); /*!< maximum compression level available */
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+#define ZSTD_COMPRESSBOUND(srcSize) ((srcSize) + ((srcSize)>>8) + (((srcSize) < 128 KB) ? ((128 KB - (srcSize)) >> 11) /* margin, from 64 to 0 */ : 0)) /* this formula ensures that bound(A) + bound(B) <= bound(A+B) as long as A and B >= 128 KB */
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ZSTDLIB_API size_t ZSTD_compressBound(size_t srcSize); /*!< maximum compressed size in worst case scenario */
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ZSTDLIB_API unsigned ZSTD_isError(size_t code); /*!< tells if a `size_t` function result is an error code */
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ZSTDLIB_API const char* ZSTD_getErrorName(size_t code); /*!< provides readable string from an error code */
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+ZSTDLIB_API int ZSTD_maxCLevel(void); /*!< maximum compression level available */
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/***************************************
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@@ -375,27 +377,31 @@ ZSTDLIB_API size_t ZSTD_DStreamOutSize(void); /*!< recommended size for output
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#define ZSTD_MAGIC_SKIPPABLE_START 0x184D2A50U
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#define ZSTD_MAGIC_DICTIONARY 0xEC30A437 /* v0.7+ */
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-#define ZSTD_WINDOWLOG_MAX_32 27
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-#define ZSTD_WINDOWLOG_MAX_64 27
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+#define ZSTD_WINDOWLOG_MAX_32 30
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+#define ZSTD_WINDOWLOG_MAX_64 31
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#define ZSTD_WINDOWLOG_MAX ((unsigned)(sizeof(size_t) == 4 ? ZSTD_WINDOWLOG_MAX_32 : ZSTD_WINDOWLOG_MAX_64))
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-#define ZSTD_WINDOWLOG_MIN 10
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-#define ZSTD_HASHLOG_MAX ZSTD_WINDOWLOG_MAX
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-#define ZSTD_HASHLOG_MIN 6
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-#define ZSTD_CHAINLOG_MAX (ZSTD_WINDOWLOG_MAX+1)
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-#define ZSTD_CHAINLOG_MIN ZSTD_HASHLOG_MIN
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-#define ZSTD_HASHLOG3_MAX 17
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-#define ZSTD_SEARCHLOG_MAX (ZSTD_WINDOWLOG_MAX-1)
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-#define ZSTD_SEARCHLOG_MIN 1
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-#define ZSTD_SEARCHLENGTH_MAX 7 /* only for ZSTD_fast, other strategies are limited to 6 */
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-#define ZSTD_SEARCHLENGTH_MIN 3 /* only for ZSTD_btopt, other strategies are limited to 4 */
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-#define ZSTD_TARGETLENGTH_MIN 4
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-#define ZSTD_TARGETLENGTH_MAX 999
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-
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-#define ZSTD_FRAMEHEADERSIZE_MAX 18 /* for static allocation */
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-#define ZSTD_FRAMEHEADERSIZE_MIN 6
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-static const size_t ZSTD_frameHeaderSize_prefix = 5; /* minimum input size to know frame header size */
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-static const size_t ZSTD_frameHeaderSize_max = ZSTD_FRAMEHEADERSIZE_MAX;
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+#define ZSTD_WINDOWLOG_MIN 10
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+#define ZSTD_HASHLOG_MAX MIN(ZSTD_WINDOWLOG_MAX, 30)
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+#define ZSTD_HASHLOG_MIN 6
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+#define ZSTD_CHAINLOG_MAX MIN(ZSTD_WINDOWLOG_MAX+1, 30)
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+#define ZSTD_CHAINLOG_MIN ZSTD_HASHLOG_MIN
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+#define ZSTD_HASHLOG3_MAX 17
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+#define ZSTD_SEARCHLOG_MAX (ZSTD_WINDOWLOG_MAX-1)
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+#define ZSTD_SEARCHLOG_MIN 1
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+#define ZSTD_SEARCHLENGTH_MAX 7 /* only for ZSTD_fast, other strategies are limited to 6 */
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+#define ZSTD_SEARCHLENGTH_MIN 3 /* only for ZSTD_btopt, other strategies are limited to 4 */
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+#define ZSTD_TARGETLENGTH_MIN 4 /* only useful for btopt */
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+#define ZSTD_TARGETLENGTH_MAX 999 /* only useful for btopt */
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+#define ZSTD_LDM_MINMATCH_MIN 4
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+#define ZSTD_LDM_MINMATCH_MAX 4096
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+#define ZSTD_LDM_BUCKETSIZELOG_MAX 8
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+
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+#define ZSTD_FRAMEHEADERSIZE_PREFIX 5 /* minimum input size to know frame header size */
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+#define ZSTD_FRAMEHEADERSIZE_MIN 6
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+#define ZSTD_FRAMEHEADERSIZE_MAX 18 /* for static allocation */
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+static const size_t ZSTD_frameHeaderSize_prefix = ZSTD_FRAMEHEADERSIZE_PREFIX;
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static const size_t ZSTD_frameHeaderSize_min = ZSTD_FRAMEHEADERSIZE_MIN;
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+static const size_t ZSTD_frameHeaderSize_max = ZSTD_FRAMEHEADERSIZE_MAX;
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static const size_t ZSTD_skippableHeaderSize = 8; /* magic number + skippable frame length */
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@@ -424,6 +430,8 @@ typedef struct {
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ZSTD_frameParameters fParams;
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} ZSTD_parameters;
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+typedef struct ZSTD_CCtx_params_s ZSTD_CCtx_params;
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+
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/*= Custom memory allocation functions */
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typedef void* (*ZSTD_allocFunction) (void* opaque, size_t size);
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typedef void (*ZSTD_freeFunction) (void* opaque, void* address);
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@@ -480,7 +488,7 @@ ZSTDLIB_API size_t ZSTD_frameHeaderSize(const void* src, size_t srcSize);
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/*! ZSTD_sizeof_*() :
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* These functions give the current memory usage of selected object.
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- * Object memory usage can evolve if it's re-used multiple times. */
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+ * Object memory usage can evolve when re-used multiple times. */
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ZSTDLIB_API size_t ZSTD_sizeof_CCtx(const ZSTD_CCtx* cctx);
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ZSTDLIB_API size_t ZSTD_sizeof_DCtx(const ZSTD_DCtx* dctx);
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ZSTDLIB_API size_t ZSTD_sizeof_CStream(const ZSTD_CStream* zcs);
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@@ -493,18 +501,21 @@ ZSTDLIB_API size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict);
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* of a future {D,C}Ctx, before its creation.
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* ZSTD_estimateCCtxSize() will provide a budget large enough for any compression level up to selected one.
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* It will also consider src size to be arbitrarily "large", which is worst case.
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- * If srcSize is known to always be small, ZSTD_estimateCCtxSize_advanced() can provide a tighter estimation.
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- * ZSTD_estimateCCtxSize_advanced() can be used in tandem with ZSTD_getCParams() to create cParams from compressionLevel.
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+ * If srcSize is known to always be small, ZSTD_estimateCCtxSize_usingCParams() can provide a tighter estimation.
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+ * ZSTD_estimateCCtxSize_usingCParams() can be used in tandem with ZSTD_getCParams() to create cParams from compressionLevel.
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+ * ZSTD_estimateCCtxSize_usingCCtxParams() can be used in tandem with ZSTD_CCtxParam_setParameter(). Only single-threaded compression is supported. This function will return an error code if ZSTD_p_nbThreads is > 1.
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* Note : CCtx estimation is only correct for single-threaded compression */
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ZSTDLIB_API size_t ZSTD_estimateCCtxSize(int compressionLevel);
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-ZSTDLIB_API size_t ZSTD_estimateCCtxSize_advanced(ZSTD_compressionParameters cParams);
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+ZSTDLIB_API size_t ZSTD_estimateCCtxSize_usingCParams(ZSTD_compressionParameters cParams);
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+ZSTDLIB_API size_t ZSTD_estimateCCtxSize_usingCCtxParams(const ZSTD_CCtx_params* params);
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ZSTDLIB_API size_t ZSTD_estimateDCtxSize(void);
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-/*! ZSTD_estimate?StreamSize() :
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+/*! ZSTD_estimateCStreamSize() :
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* ZSTD_estimateCStreamSize() will provide a budget large enough for any compression level up to selected one.
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* It will also consider src size to be arbitrarily "large", which is worst case.
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- * If srcSize is known to always be small, ZSTD_estimateCStreamSize_advanced() can provide a tighter estimation.
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- * ZSTD_estimateCStreamSize_advanced() can be used in tandem with ZSTD_getCParams() to create cParams from compressionLevel.
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+ * If srcSize is known to always be small, ZSTD_estimateCStreamSize_usingCParams() can provide a tighter estimation.
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+ * ZSTD_estimateCStreamSize_usingCParams() can be used in tandem with ZSTD_getCParams() to create cParams from compressionLevel.
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+ * ZSTD_estimateCStreamSize_usingCCtxParams() can be used in tandem with ZSTD_CCtxParam_setParameter(). Only single-threaded compression is supported. This function will return an error code if ZSTD_p_nbThreads is set to a value > 1.
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* Note : CStream estimation is only correct for single-threaded compression.
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* ZSTD_DStream memory budget depends on window Size.
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* This information can be passed manually, using ZSTD_estimateDStreamSize,
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@@ -513,17 +524,24 @@ ZSTDLIB_API size_t ZSTD_estimateDCtxSize(void);
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* an internal ?Dict will be created, which additional size is not estimated here.
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* In this case, get total size by adding ZSTD_estimate?DictSize */
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ZSTDLIB_API size_t ZSTD_estimateCStreamSize(int compressionLevel);
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-ZSTDLIB_API size_t ZSTD_estimateCStreamSize_advanced(ZSTD_compressionParameters cParams);
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+ZSTDLIB_API size_t ZSTD_estimateCStreamSize_usingCParams(ZSTD_compressionParameters cParams);
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+ZSTDLIB_API size_t ZSTD_estimateCStreamSize_usingCCtxParams(const ZSTD_CCtx_params* params);
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ZSTDLIB_API size_t ZSTD_estimateDStreamSize(size_t windowSize);
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ZSTDLIB_API size_t ZSTD_estimateDStreamSize_fromFrame(const void* src, size_t srcSize);
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+typedef enum {
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+ ZSTD_dlm_byCopy = 0, /**< Copy dictionary content internally */
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+ ZSTD_dlm_byRef, /**< Reference dictionary content -- the dictionary buffer must outlive its users. */
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+} ZSTD_dictLoadMethod_e;
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+
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/*! ZSTD_estimate?DictSize() :
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* ZSTD_estimateCDictSize() will bet that src size is relatively "small", and content is copied, like ZSTD_createCDict().
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- * ZSTD_estimateCStreamSize_advanced() makes it possible to control precisely compression parameters, like ZSTD_createCDict_advanced().
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- * Note : dictionary created "byReference" are smaller */
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+ * ZSTD_estimateCStreamSize_advanced_usingCParams() makes it possible to control precisely compression parameters, like ZSTD_createCDict_advanced().
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+ * Note : dictionary created by reference using ZSTD_dlm_byRef are smaller
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+ */
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ZSTDLIB_API size_t ZSTD_estimateCDictSize(size_t dictSize, int compressionLevel);
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-ZSTDLIB_API size_t ZSTD_estimateCDictSize_advanced(size_t dictSize, ZSTD_compressionParameters cParams, unsigned byReference);
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-ZSTDLIB_API size_t ZSTD_estimateDDictSize(size_t dictSize, unsigned byReference);
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+ZSTDLIB_API size_t ZSTD_estimateCDictSize_advanced(size_t dictSize, ZSTD_compressionParameters cParams, ZSTD_dictLoadMethod_e dictLoadMethod);
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+ZSTDLIB_API size_t ZSTD_estimateDDictSize(size_t dictSize, ZSTD_dictLoadMethod_e dictLoadMethod);
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/***************************************
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@@ -551,24 +569,12 @@ ZSTDLIB_API ZSTD_CCtx* ZSTD_createCCtx_advanced(ZSTD_customMem customMem);
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ZSTDLIB_API ZSTD_CCtx* ZSTD_initStaticCCtx(void* workspace, size_t workspaceSize);
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-/* !!! To be deprecated !!! */
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-typedef enum {
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- ZSTD_p_forceWindow, /* Force back-references to remain < windowSize, even when referencing Dictionary content (default:0) */
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- ZSTD_p_forceRawDict /* Force loading dictionary in "content-only" mode (no header analysis) */
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-} ZSTD_CCtxParameter;
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-/*! ZSTD_setCCtxParameter() :
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- * Set advanced parameters, selected through enum ZSTD_CCtxParameter
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- * @result : 0, or an error code (which can be tested with ZSTD_isError()) */
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-ZSTDLIB_API size_t ZSTD_setCCtxParameter(ZSTD_CCtx* cctx, ZSTD_CCtxParameter param, unsigned value);
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-
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-
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/*! ZSTD_createCDict_byReference() :
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* Create a digested dictionary for compression
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* Dictionary content is simply referenced, and therefore stays in dictBuffer.
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* It is important that dictBuffer outlives CDict, it must remain read accessible throughout the lifetime of CDict */
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ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict_byReference(const void* dictBuffer, size_t dictSize, int compressionLevel);
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-
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typedef enum { ZSTD_dm_auto=0, /* dictionary is "full" if it starts with ZSTD_MAGIC_DICTIONARY, otherwise it is "rawContent" */
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ZSTD_dm_rawContent, /* ensures dictionary is always loaded as rawContent, even if it starts with ZSTD_MAGIC_DICTIONARY */
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ZSTD_dm_fullDict /* refuses to load a dictionary if it does not respect Zstandard's specification */
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@@ -576,7 +582,8 @@ typedef enum { ZSTD_dm_auto=0, /* dictionary is "full" if it starts with
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/*! ZSTD_createCDict_advanced() :
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* Create a ZSTD_CDict using external alloc and free, and customized compression parameters */
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ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict_advanced(const void* dict, size_t dictSize,
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- unsigned byReference, ZSTD_dictMode_e dictMode,
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+ ZSTD_dictLoadMethod_e dictLoadMethod,
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+ ZSTD_dictMode_e dictMode,
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ZSTD_compressionParameters cParams,
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ZSTD_customMem customMem);
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@@ -596,7 +603,7 @@ ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict_advanced(const void* dict, size_t dictS
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ZSTDLIB_API ZSTD_CDict* ZSTD_initStaticCDict(
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void* workspace, size_t workspaceSize,
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const void* dict, size_t dictSize,
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- unsigned byReference, ZSTD_dictMode_e dictMode,
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+ ZSTD_dictLoadMethod_e dictLoadMethod, ZSTD_dictMode_e dictMode,
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ZSTD_compressionParameters cParams);
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/*! ZSTD_getCParams() :
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@@ -674,7 +681,8 @@ ZSTDLIB_API ZSTD_DDict* ZSTD_createDDict_byReference(const void* dictBuffer, siz
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/*! ZSTD_createDDict_advanced() :
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* Create a ZSTD_DDict using external alloc and free, optionally by reference */
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ZSTDLIB_API ZSTD_DDict* ZSTD_createDDict_advanced(const void* dict, size_t dictSize,
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- unsigned byReference, ZSTD_customMem customMem);
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+ ZSTD_dictLoadMethod_e dictLoadMethod,
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+ ZSTD_customMem customMem);
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/*! ZSTD_initStaticDDict() :
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* Generate a digested dictionary in provided memory area.
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@@ -689,7 +697,7 @@ ZSTDLIB_API ZSTD_DDict* ZSTD_createDDict_advanced(const void* dict, size_t dictS
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*/
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ZSTDLIB_API ZSTD_DDict* ZSTD_initStaticDDict(void* workspace, size_t workspaceSize,
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const void* dict, size_t dictSize,
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- unsigned byReference);
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+ ZSTD_dictLoadMethod_e dictLoadMethod);
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/*! ZSTD_getDictID_fromDict() :
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* Provides the dictID stored within dictionary.
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@@ -724,9 +732,9 @@ ZSTDLIB_API unsigned ZSTD_getDictID_fromFrame(const void* src, size_t srcSize);
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ZSTDLIB_API ZSTD_CStream* ZSTD_createCStream_advanced(ZSTD_customMem customMem);
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ZSTDLIB_API ZSTD_CStream* ZSTD_initStaticCStream(void* workspace, size_t workspaceSize); /**< same as ZSTD_initStaticCCtx() */
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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 */
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-ZSTDLIB_API size_t ZSTD_initCStream_usingDict(ZSTD_CStream* zcs, const void* dict, size_t dictSize, int compressionLevel); /**< creates of an internal CDict (incompatible with static CCtx), except if dict == NULL or dictSize < 8, in which case no dict is used. */
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+ZSTDLIB_API size_t ZSTD_initCStream_usingDict(ZSTD_CStream* zcs, const void* dict, size_t dictSize, int compressionLevel); /**< creates of an internal CDict (incompatible with static CCtx), except if dict == NULL or dictSize < 8, in which case no dict is used. Note: dict is loaded with ZSTD_dm_auto (treated as a full zstd dictionary if it begins with ZSTD_MAGIC_DICTIONARY, else as raw content) and ZSTD_dlm_byCopy.*/
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ZSTDLIB_API size_t ZSTD_initCStream_advanced(ZSTD_CStream* zcs, const void* dict, size_t dictSize,
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- 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 */
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+ 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. dict is loaded with ZSTD_dm_auto and ZSTD_dlm_byCopy. */
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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 */
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ZSTDLIB_API size_t ZSTD_initCStream_usingCDict_advanced(ZSTD_CStream* zcs, const ZSTD_CDict* cdict, ZSTD_frameParameters fParams, unsigned long long pledgedSrcSize); /**< same as ZSTD_initCStream_usingCDict(), with control over frame parameters */
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@@ -741,12 +749,12 @@ ZSTDLIB_API size_t ZSTD_resetCStream(ZSTD_CStream* zcs, unsigned long long pledg
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/*===== Advanced Streaming decompression functions =====*/
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-typedef enum { DStream_p_maxWindowSize } ZSTD_DStreamParameter_e;
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ZSTDLIB_API ZSTD_DStream* ZSTD_createDStream_advanced(ZSTD_customMem customMem);
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ZSTDLIB_API ZSTD_DStream* ZSTD_initStaticDStream(void* workspace, size_t workspaceSize); /**< same as ZSTD_initStaticDCtx() */
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-ZSTDLIB_API size_t ZSTD_setDStreamParameter(ZSTD_DStream* zds, ZSTD_DStreamParameter_e paramType, unsigned paramValue);
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-ZSTDLIB_API size_t ZSTD_initDStream_usingDict(ZSTD_DStream* zds, const void* dict, size_t dictSize); /**< note: a dict will not be used if dict == NULL or dictSize < 8 */
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-ZSTDLIB_API size_t ZSTD_initDStream_usingDDict(ZSTD_DStream* zds, const ZSTD_DDict* ddict); /**< note : ddict will just be referenced, and must outlive decompression session */
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+typedef enum { DStream_p_maxWindowSize } ZSTD_DStreamParameter_e;
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+ZSTDLIB_API size_t ZSTD_setDStreamParameter(ZSTD_DStream* zds, ZSTD_DStreamParameter_e paramType, unsigned paramValue); /* obsolete : this API will be removed in a future version */
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+ZSTDLIB_API size_t ZSTD_initDStream_usingDict(ZSTD_DStream* zds, const void* dict, size_t dictSize); /**< note: no dictionary will be used if dict == NULL or dictSize < 8 */
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+ZSTDLIB_API size_t ZSTD_initDStream_usingDDict(ZSTD_DStream* zds, const ZSTD_DDict* ddict); /**< note : ddict is referenced, it must outlive decompression session */
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ZSTDLIB_API size_t ZSTD_resetDStream(ZSTD_DStream* zds); /**< re-use decompression parameters from previous init; saves dictionary loading */
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@@ -754,8 +762,8 @@ ZSTDLIB_API size_t ZSTD_resetDStream(ZSTD_DStream* zds); /**< re-use decompress
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* Buffer-less and synchronous inner streaming functions
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*
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* This is an advanced API, giving full control over buffer management, for users which need direct control over memory.
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-* But it's also a complex one, with many restrictions (documented below).
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-* Prefer using normal streaming API for an easier experience
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+* But it's also a complex one, with several restrictions, documented below.
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+* Prefer normal streaming API for an easier experience.
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********************************************************************* */
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/**
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@@ -772,8 +780,8 @@ ZSTDLIB_API size_t ZSTD_resetDStream(ZSTD_DStream* zds); /**< re-use decompress
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Then, consume your input using ZSTD_compressContinue().
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There are some important considerations to keep in mind when using this advanced function :
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- - ZSTD_compressContinue() has no internal buffer. It uses externally provided buffer only.
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- - Interface is synchronous : input is consumed entirely and produce 1+ (or more) compressed blocks.
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+ - ZSTD_compressContinue() has no internal buffer. It uses externally provided buffers only.
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+ - Interface is synchronous : input is consumed entirely and produces 1+ compressed blocks.
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- Caller must ensure there is enough space in `dst` to store compressed data under worst case scenario.
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Worst case evaluation is provided by ZSTD_compressBound().
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ZSTD_compressContinue() doesn't guarantee recover after a failed compression.
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@@ -784,9 +792,9 @@ ZSTDLIB_API size_t ZSTD_resetDStream(ZSTD_DStream* zds); /**< re-use decompress
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Finish a frame with ZSTD_compressEnd(), which will write the last block(s) and optional checksum.
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It's possible to use srcSize==0, in which case, it will write a final empty block to end the frame.
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- Without last block mark, frames will be considered unfinished (corrupted) by decoders.
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+ Without last block mark, frames are considered unfinished (hence corrupted) by compliant decoders.
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- `ZSTD_CCtx` object can be re-used (ZSTD_compressBegin()) to compress some new frame.
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+ `ZSTD_CCtx` object can be re-used (ZSTD_compressBegin()) to compress again.
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*/
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/*===== Buffer-less streaming compression functions =====*/
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@@ -809,40 +817,53 @@ ZSTDLIB_API size_t ZSTD_compressEnd(ZSTD_CCtx* cctx, void* dst, size_t dstCapaci
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A ZSTD_DCtx object can be re-used multiple times.
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First typical operation is to retrieve frame parameters, using ZSTD_getFrameHeader().
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- It fills a ZSTD_frameHeader structure with important information to correctly decode the frame,
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- such as minimum rolling buffer size to allocate to decompress data (`windowSize`),
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- and the dictionary ID in use.
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- (Note : content size is optional, it may not be present. 0 means : content size unknown).
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- Note that these values could be wrong, either because of data malformation, or because an attacker is spoofing deliberate false information.
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- As a consequence, check that values remain within valid application range, especially `windowSize`, before allocation.
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- Each application can set its own limit, depending on local restrictions.
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- For extended interoperability, it is recommended to support windowSize of at least 8 MB.
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Frame header is extracted from the beginning of compressed frame, so providing only the frame's beginning is enough.
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Data fragment must be large enough to ensure successful decoding.
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- `ZSTD_frameHeaderSize_max` bytes is guaranteed to always be large enough.
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+ `ZSTD_frameHeaderSize_max` bytes is guaranteed to always be large enough.
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@result : 0 : successful decoding, the `ZSTD_frameHeader` structure is correctly filled.
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>0 : `srcSize` is too small, please provide at least @result bytes on next attempt.
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errorCode, which can be tested using ZSTD_isError().
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- Start decompression, with ZSTD_decompressBegin().
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+ It fills a ZSTD_frameHeader structure with important information to correctly decode the frame,
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+ such as the dictionary ID, content size, or maximum back-reference distance (`windowSize`).
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+ Note that these values could be wrong, either because of data corruption, or because a 3rd party deliberately spoofs false information.
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+ As a consequence, check that values remain within valid application range.
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+ For example, do not allocate memory blindly, check that `windowSize` is within expectation.
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+ Each application can set its own limits, depending on local restrictions.
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+ For extended interoperability, it is recommended to support `windowSize` of at least 8 MB.
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+
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+ ZSTD_decompressContinue() needs previous data blocks during decompression, up to `windowSize` bytes.
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+ ZSTD_decompressContinue() is very sensitive to contiguity,
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+ if 2 blocks don't follow each other, make sure that either the compressor breaks contiguity at the same place,
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+ or that previous contiguous segment is large enough to properly handle maximum back-reference distance.
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+ There are multiple ways to guarantee this condition.
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+
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+ The most memory efficient way is to use a round buffer of sufficient size.
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+ Sufficient size is determined by invoking ZSTD_decodingBufferSize_min(),
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+ which can @return an error code if required value is too large for current system (in 32-bits mode).
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+ In a round buffer methodology, ZSTD_decompressContinue() decompresses each block next to previous one,
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+ up to the moment there is not enough room left in the buffer to guarantee decoding another full block,
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+ which maximum size is provided in `ZSTD_frameHeader` structure, field `blockSizeMax`.
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+ At which point, decoding can resume from the beginning of the buffer.
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+ Note that already decoded data stored in the buffer should be flushed before being overwritten.
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+
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+ There are alternatives possible, for example using two or more buffers of size `windowSize` each, though they consume more memory.
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+
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+ Finally, if you control the compression process, you can also ignore all buffer size rules,
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+ as long as the encoder and decoder progress in "lock-step",
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+ aka use exactly the same buffer sizes, break contiguity at the same place, etc.
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+
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+ Once buffers are setup, start decompression, with ZSTD_decompressBegin().
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If decompression requires a dictionary, use ZSTD_decompressBegin_usingDict() or ZSTD_decompressBegin_usingDDict().
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- Alternatively, you can copy a prepared context, using ZSTD_copyDCtx().
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Then use ZSTD_nextSrcSizeToDecompress() and ZSTD_decompressContinue() alternatively.
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ZSTD_nextSrcSizeToDecompress() tells how many bytes to provide as 'srcSize' to ZSTD_decompressContinue().
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ZSTD_decompressContinue() requires this _exact_ amount of bytes, or it will fail.
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- @result of ZSTD_decompressContinue() is the number of bytes regenerated within 'dst' (necessarily <= dstCapacity).
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- It can be zero, which is not an error; it just means ZSTD_decompressContinue() has decoded some metadata item.
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+ @result of ZSTD_decompressContinue() is the number of bytes regenerated within 'dst' (necessarily <= dstCapacity).
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+ It can be zero : it just means ZSTD_decompressContinue() has decoded some metadata item.
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It can also be an error code, which can be tested with ZSTD_isError().
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- ZSTD_decompressContinue() needs previous data blocks during decompression, up to `windowSize`.
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- They should preferably be located contiguously, prior to current block.
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- Alternatively, a round buffer of sufficient size is also possible. Sufficient size is determined by frame parameters.
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- ZSTD_decompressContinue() is very sensitive to contiguity,
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- if 2 blocks don't follow each other, make sure that either the compressor breaks contiguity at the same place,
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- or that previous contiguous segment is large enough to properly handle maximum back-reference.
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-
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A frame is fully decoded when ZSTD_nextSrcSizeToDecompress() returns zero.
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Context can then be reset to start a new decompression.
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@@ -852,75 +873,101 @@ ZSTDLIB_API size_t ZSTD_compressEnd(ZSTD_CCtx* cctx, void* dst, size_t dstCapaci
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== Special case : skippable frames ==
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Skippable frames allow integration of user-defined data into a flow of concatenated frames.
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- Skippable frames will be ignored (skipped) by a decompressor. The format of skippable frames is as follows :
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+ Skippable frames will be ignored (skipped) by decompressor.
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+ The format of skippable frames is as follows :
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a) Skippable frame ID - 4 Bytes, Little endian format, any value from 0x184D2A50 to 0x184D2A5F
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b) Frame Size - 4 Bytes, Little endian format, unsigned 32-bits
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c) Frame Content - any content (User Data) of length equal to Frame Size
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- For skippable frames ZSTD_decompressContinue() always returns 0.
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- For skippable frames ZSTD_getFrameHeader() returns fparamsPtr->windowLog==0 what means that a frame is skippable.
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- Note : If fparamsPtr->frameContentSize==0, it is ambiguous: the frame might actually be a Zstd encoded frame with no content.
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- For purposes of decompression, it is valid in both cases to skip the frame using
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- ZSTD_findFrameCompressedSize to find its size in bytes.
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- It also returns Frame Size as fparamsPtr->frameContentSize.
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+ For skippable frames ZSTD_getFrameHeader() returns zfhPtr->frameType==ZSTD_skippableFrame.
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+ For skippable frames ZSTD_decompressContinue() always returns 0 : it only skips the content.
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*/
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/*===== Buffer-less streaming decompression functions =====*/
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typedef enum { ZSTD_frame, ZSTD_skippableFrame } ZSTD_frameType_e;
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typedef struct {
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- unsigned long long frameContentSize; /* ZSTD_CONTENTSIZE_UNKNOWN means this field is not available. 0 means "empty" */
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+ unsigned long long frameContentSize; /* if == ZSTD_CONTENTSIZE_UNKNOWN, it means this field is not available. 0 means "empty" */
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unsigned long long windowSize; /* can be very large, up to <= frameContentSize */
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+ unsigned blockSizeMax;
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ZSTD_frameType_e frameType; /* if == ZSTD_skippableFrame, frameContentSize is the size of skippable content */
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unsigned headerSize;
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unsigned dictID;
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unsigned checksumFlag;
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} ZSTD_frameHeader;
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ZSTDLIB_API size_t ZSTD_getFrameHeader(ZSTD_frameHeader* zfhPtr, const void* src, size_t srcSize); /**< doesn't consume input */
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+ZSTDLIB_API size_t ZSTD_decodingBufferSize_min(unsigned long long windowSize, unsigned long long frameContentSize); /**< when frame content size is not known, pass in frameContentSize == ZSTD_CONTENTSIZE_UNKNOWN */
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+
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ZSTDLIB_API size_t ZSTD_decompressBegin(ZSTD_DCtx* dctx);
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ZSTDLIB_API size_t ZSTD_decompressBegin_usingDict(ZSTD_DCtx* dctx, const void* dict, size_t dictSize);
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ZSTDLIB_API size_t ZSTD_decompressBegin_usingDDict(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict);
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-ZSTDLIB_API void ZSTD_copyDCtx(ZSTD_DCtx* dctx, const ZSTD_DCtx* preparedDCtx);
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ZSTDLIB_API size_t ZSTD_nextSrcSizeToDecompress(ZSTD_DCtx* dctx);
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ZSTDLIB_API size_t ZSTD_decompressContinue(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);
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+
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+/* misc */
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+ZSTDLIB_API void ZSTD_copyDCtx(ZSTD_DCtx* dctx, const ZSTD_DCtx* preparedDCtx);
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typedef enum { ZSTDnit_frameHeader, ZSTDnit_blockHeader, ZSTDnit_block, ZSTDnit_lastBlock, ZSTDnit_checksum, ZSTDnit_skippableFrame } ZSTD_nextInputType_e;
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ZSTDLIB_API ZSTD_nextInputType_e ZSTD_nextInputType(ZSTD_DCtx* dctx);
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-/*=== New advanced API (experimental, and compression only) ===*/
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+/* ============================================ */
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+/** New advanced API (experimental) */
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+/* ============================================ */
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/* notes on API design :
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- * In this proposal, parameters are pushed one by one into an existing CCtx,
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+ * In this proposal, parameters are pushed one by one into an existing context,
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* and then applied on all subsequent compression jobs.
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* When no parameter is ever provided, CCtx is created with compression level ZSTD_CLEVEL_DEFAULT.
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*
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* This API is intended to replace all others experimental API.
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* It can basically do all other use cases, and even new ones.
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- * It stands a good chance to become "stable",
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- * after a reasonable testing period.
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+ * In constrast with _advanced() variants, it stands a reasonable chance to become "stable",
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+ * after a good testing period.
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*/
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/* note on naming convention :
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* Initially, the API favored names like ZSTD_setCCtxParameter() .
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* In this proposal, convention is changed towards ZSTD_CCtx_setParameter() .
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* The main driver is that it identifies more clearly the target object type.
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- * It feels clearer in light of potential variants :
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+ * It feels clearer when considering multiple targets :
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* ZSTD_CDict_setParameter() (rather than ZSTD_setCDictParameter())
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- * ZSTD_DCtx_setParameter() (rather than ZSTD_setDCtxParameter() )
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- * Left variant feels easier to distinguish.
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+ * ZSTD_CCtxParams_setParameter() (rather than ZSTD_setCCtxParamsParameter() )
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+ * etc...
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*/
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/* note on enum design :
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- * All enum will be manually set to explicit values before reaching "stable API" status */
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+ * All enum will be pinned to explicit values before reaching "stable API" status */
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typedef enum {
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+ /* Question : should we have a format ZSTD_f_auto ?
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+ * For the time being, it would mean exactly the same as ZSTD_f_zstd1.
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+ * But, in the future, should several formats be supported,
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+ * on the compression side, it would mean "default format".
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+ * On the decompression side, it would mean "multi format",
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+ * and ZSTD_f_zstd1 could be reserved to mean "accept *only* zstd frames".
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+ * Since meaning is a little different, another option could be to define different enums for compression and decompression.
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+ * This question could be kept for later, when there are actually multiple formats to support,
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+ * but there is also the question of pinning enum values, and pinning value `0` is especially important */
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+ ZSTD_f_zstd1 = 0, /* zstd frame format, specified in zstd_compression_format.md (default) */
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+ ZSTD_f_zstd1_magicless, /* Variant of zstd frame format, without initial 4-bytes magic number.
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+ * Useful to save 4 bytes per generated frame.
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+ * Decoder cannot recognise automatically this format, requiring instructions. */
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+} ZSTD_format_e;
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+
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+typedef enum {
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+ /* compression format */
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+ ZSTD_p_format = 10, /* See ZSTD_format_e enum definition.
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+ * Cast selected format as unsigned for ZSTD_CCtx_setParameter() compatibility. */
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+
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/* compression parameters */
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ZSTD_p_compressionLevel=100, /* Update all compression parameters according to pre-defined cLevel table
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* Default level is ZSTD_CLEVEL_DEFAULT==3.
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* Special: value 0 means "do not change cLevel". */
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ZSTD_p_windowLog, /* Maximum allowed back-reference distance, expressed as power of 2.
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* Must be clamped between ZSTD_WINDOWLOG_MIN and ZSTD_WINDOWLOG_MAX.
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- * Special: value 0 means "do not change windowLog". */
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+ * Special: value 0 means "do not change windowLog".
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+ * Note: Using a window size greater than ZSTD_MAXWINDOWSIZE_DEFAULT (default: 2^27)
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+ * requires setting the maximum window size at least as large during decompression. */
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ZSTD_p_hashLog, /* Size of the probe table, as a power of 2.
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* Resulting table size is (1 << (hashLog+2)).
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* Must be clamped between ZSTD_HASHLOG_MIN and ZSTD_HASHLOG_MAX.
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@@ -959,12 +1006,6 @@ typedef enum {
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ZSTD_p_checksumFlag, /* A 32-bits checksum of content is written at end of frame (default:0) */
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ZSTD_p_dictIDFlag, /* When applicable, dictID of dictionary is provided in frame header (default:1) */
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- /* dictionary parameters (must be set before ZSTD_CCtx_loadDictionary) */
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- ZSTD_p_dictMode=300, /* Select how dictionary content must be interpreted. Value must be from type ZSTD_dictMode_e.
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- * default : 0==auto : dictionary will be "full" if it respects specification, otherwise it will be "rawContent" */
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- ZSTD_p_refDictContent, /* Dictionary content will be referenced, instead of copied (default:0==byCopy).
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- * It requires that dictionary buffer outlives its users */
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-
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/* multi-threading parameters */
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ZSTD_p_nbThreads=400, /* Select how many threads a compression job can spawn (default:1)
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* More threads improve speed, but also increase memory usage.
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@@ -980,6 +1021,35 @@ typedef enum {
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/* advanced parameters - may not remain available after API update */
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ZSTD_p_forceMaxWindow=1100, /* Force back-reference distances to remain < windowSize,
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* even when referencing into Dictionary content (default:0) */
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+ ZSTD_p_enableLongDistanceMatching=1200, /* Enable long distance matching.
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+ * This parameter is designed to improve the compression
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+ * ratio for large inputs with long distance matches.
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+ * This increases the memory usage as well as window size.
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+ * Note: setting this parameter sets all the LDM parameters
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+ * as well as ZSTD_p_windowLog. It should be set after
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+ * ZSTD_p_compressionLevel and before ZSTD_p_windowLog and
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+ * other LDM parameters. Setting the compression level
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+ * after this parameter overrides the window log, though LDM
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+ * will remain enabled until explicitly disabled. */
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+ ZSTD_p_ldmHashLog, /* Size of the table for long distance matching, as a power of 2.
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+ * Larger values increase memory usage and compression ratio, but decrease
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+ * compression speed.
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+ * Must be clamped between ZSTD_HASHLOG_MIN and ZSTD_HASHLOG_MAX
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+ * (default: windowlog - 7). */
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+ ZSTD_p_ldmMinMatch, /* Minimum size of searched matches for long distance matcher.
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+ * Larger/too small values usually decrease compression ratio.
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+ * Must be clamped between ZSTD_LDM_MINMATCH_MIN
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+ * and ZSTD_LDM_MINMATCH_MAX (default: 64). */
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+ ZSTD_p_ldmBucketSizeLog, /* Log size of each bucket in the LDM hash table for collision resolution.
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+ * Larger values usually improve collision resolution but may decrease
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+ * compression speed.
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+ * The maximum value is ZSTD_LDM_BUCKETSIZELOG_MAX (default: 3). */
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+ ZSTD_p_ldmHashEveryLog, /* Frequency of inserting/looking up entries in the LDM hash table.
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+ * The default is MAX(0, (windowLog - ldmHashLog)) to
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+ * optimize hash table usage.
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+ * Larger values improve compression speed. Deviating far from the
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+ * default value will likely result in a decrease in compression ratio.
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+ * Must be clamped between 0 and ZSTD_WINDOWLOG_MAX - ZSTD_HASHLOG_MIN. */
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} ZSTD_cParameter;
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@@ -1007,14 +1077,22 @@ ZSTDLIB_API size_t ZSTD_CCtx_setPledgedSrcSize(ZSTD_CCtx* cctx, unsigned long lo
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* @result : 0, or an error code (which can be tested with ZSTD_isError()).
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* Special : Adding a NULL (or 0-size) dictionary invalidates any previous dictionary,
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* meaning "return to no-dictionary mode".
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- * Note 1 : `dict` content will be copied internally,
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- * except if ZSTD_p_refDictContent is set before loading.
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+ * Note 1 : `dict` content will be copied internally. Use
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+ * ZSTD_CCtx_loadDictionary_byReference() to reference dictionary
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+ * content instead. The dictionary buffer must then outlive its
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+ * users.
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* Note 2 : Loading a dictionary involves building tables, which are dependent on compression parameters.
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* For this reason, compression parameters cannot be changed anymore after loading a dictionary.
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* It's also a CPU-heavy operation, with non-negligible impact on latency.
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* Note 3 : Dictionary will be used for all future compression jobs.
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- * To return to "no-dictionary" situation, load a NULL dictionary */
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+ * To return to "no-dictionary" situation, load a NULL dictionary
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+ * Note 5 : Use ZSTD_CCtx_loadDictionary_advanced() to select how dictionary
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+ * content will be interpreted.
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+ */
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ZSTDLIB_API size_t ZSTD_CCtx_loadDictionary(ZSTD_CCtx* cctx, const void* dict, size_t dictSize);
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+ZSTDLIB_API size_t ZSTD_CCtx_loadDictionary_byReference(ZSTD_CCtx* cctx, const void* dict, size_t dictSize);
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+ZSTDLIB_API size_t ZSTD_CCtx_loadDictionary_advanced(ZSTD_CCtx* cctx, const void* dict, size_t dictSize, ZSTD_dictLoadMethod_e dictLoadMethod, ZSTD_dictMode_e dictMode);
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+
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/*! ZSTD_CCtx_refCDict() :
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* Reference a prepared dictionary, to be used for all next compression jobs.
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@@ -1040,23 +1118,26 @@ ZSTDLIB_API size_t ZSTD_CCtx_refCDict(ZSTD_CCtx* cctx, const ZSTD_CDict* cdict);
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* Note 1 : Prefix buffer is referenced. It must outlive compression job.
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* Note 2 : Referencing a prefix involves building tables, which are dependent on compression parameters.
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* It's a CPU-heavy operation, with non-negligible impact on latency.
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- * Note 3 : it's possible to alter ZSTD_p_dictMode using ZSTD_CCtx_setParameter() */
|
|
|
+ * Note 3 : By default, the prefix is treated as raw content
|
|
|
+ * (ZSTD_dm_rawContent). Use ZSTD_CCtx_refPrefix_advanced() to alter
|
|
|
+ * dictMode. */
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|
|
ZSTDLIB_API size_t ZSTD_CCtx_refPrefix(ZSTD_CCtx* cctx, const void* prefix, size_t prefixSize);
|
|
|
+ZSTDLIB_API size_t ZSTD_CCtx_refPrefix_advanced(ZSTD_CCtx* cctx, const void* prefix, size_t prefixSize, ZSTD_dictMode_e dictMode);
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|
|
typedef enum {
|
|
|
ZSTD_e_continue=0, /* collect more data, encoder transparently decides when to output result, for optimal conditions */
|
|
|
ZSTD_e_flush, /* flush any data provided so far - frame will continue, future data can still reference previous data for better compression */
|
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|
- ZSTD_e_end /* flush any remaining data and ends current frame. Any future compression starts a new frame. */
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|
|
+ ZSTD_e_end /* flush any remaining data and close current frame. Any additional data starts a new frame. */
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|
} ZSTD_EndDirective;
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|
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|
|
/*! ZSTD_compress_generic() :
|
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|
* Behave about the same as ZSTD_compressStream. To note :
|
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|
* - Compression parameters are pushed into CCtx before starting compression, using ZSTD_CCtx_setParameter()
|
|
|
* - Compression parameters cannot be changed once compression is started.
|
|
|
- * - *dstPos must be <= dstCapacity, *srcPos must be <= srcSize
|
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|
- * - *dspPos and *srcPos will be updated. They are guaranteed to remain below their respective limit.
|
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|
+ * - outpot->pos must be <= dstCapacity, input->pos must be <= srcSize
|
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|
+ * - outpot->pos and input->pos will be updated. They are guaranteed to remain below their respective limit.
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|
* - @return provides the minimum amount of data still to flush from internal buffers
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|
* or an error code, which can be tested using ZSTD_isError().
|
|
|
* if @return != 0, flush is not fully completed, there is some data left within internal buffers.
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|
@@ -1075,6 +1156,7 @@ ZSTDLIB_API size_t ZSTD_compress_generic (ZSTD_CCtx* cctx,
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* Useful after an error, or to interrupt an ongoing compression job and start a new one.
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|
* Any internal data not yet flushed is cancelled.
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|
* Dictionary (if any) is dropped.
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|
+ * All parameters are back to default values.
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|
* It's possible to modify compression parameters after a reset.
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|
*/
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|
ZSTDLIB_API void ZSTD_CCtx_reset(ZSTD_CCtx* cctx); /* Not ready yet ! */
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@@ -1083,21 +1165,187 @@ ZSTDLIB_API void ZSTD_CCtx_reset(ZSTD_CCtx* cctx); /* Not ready yet ! */
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/*! ZSTD_compress_generic_simpleArgs() :
|
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|
* Same as ZSTD_compress_generic(),
|
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|
* but using only integral types as arguments.
|
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|
- * Argument list is larger and less expressive than ZSTD_{in,out}Buffer,
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|
+ * Argument list is larger than ZSTD_{in,out}Buffer,
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|
* but can be helpful for binders from dynamic languages
|
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|
* which have troubles handling structures containing memory pointers.
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|
*/
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|
-size_t ZSTD_compress_generic_simpleArgs (
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+ZSTDLIB_API size_t ZSTD_compress_generic_simpleArgs (
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ZSTD_CCtx* cctx,
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void* dst, size_t dstCapacity, size_t* dstPos,
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|
const void* src, size_t srcSize, size_t* srcPos,
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|
ZSTD_EndDirective endOp);
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+/*! ZSTD_CCtx_params :
|
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+ * Quick howto :
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+ * - ZSTD_createCCtxParams() : Create a ZSTD_CCtx_params structure
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|
+ * - ZSTD_CCtxParam_setParameter() : Push parameters one by one into
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+ * an existing ZSTD_CCtx_params structure.
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+ * This is similar to
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+ * ZSTD_CCtx_setParameter().
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+ * - ZSTD_CCtx_setParametersUsingCCtxParams() : Apply parameters to
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+ * an existing CCtx.
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|
+ * These parameters will be applied to
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|
+ * all subsequent compression jobs.
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+ * - ZSTD_compress_generic() : Do compression using the CCtx.
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+ * - ZSTD_freeCCtxParams() : Free the memory.
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|
+ *
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|
+ * This can be used with ZSTD_estimateCCtxSize_advanced_usingCCtxParams()
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|
|
+ * for static allocation for single-threaded compression.
|
|
|
+ */
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|
|
+ZSTDLIB_API ZSTD_CCtx_params* ZSTD_createCCtxParams(void);
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|
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|
|
-/**
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|
|
- Block functions
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|
|
+/*! ZSTD_resetCCtxParams() :
|
|
|
+ * Reset params to default, with the default compression level.
|
|
|
+ */
|
|
|
+ZSTDLIB_API size_t ZSTD_resetCCtxParams(ZSTD_CCtx_params* params);
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|
|
+
|
|
|
+/*! ZSTD_initCCtxParams() :
|
|
|
+ * Initializes the compression parameters of cctxParams according to
|
|
|
+ * compression level. All other parameters are reset to their default values.
|
|
|
+ */
|
|
|
+ZSTDLIB_API size_t ZSTD_initCCtxParams(ZSTD_CCtx_params* cctxParams, int compressionLevel);
|
|
|
+
|
|
|
+/*! ZSTD_initCCtxParams_advanced() :
|
|
|
+ * Initializes the compression and frame parameters of cctxParams according to
|
|
|
+ * params. All other parameters are reset to their default values.
|
|
|
+ */
|
|
|
+ZSTDLIB_API size_t ZSTD_initCCtxParams_advanced(ZSTD_CCtx_params* cctxParams, ZSTD_parameters params);
|
|
|
+
|
|
|
+ZSTDLIB_API size_t ZSTD_freeCCtxParams(ZSTD_CCtx_params* params);
|
|
|
+
|
|
|
+/*! ZSTD_CCtxParam_setParameter() :
|
|
|
+ * Similar to ZSTD_CCtx_setParameter.
|
|
|
+ * Set one compression parameter, selected by enum ZSTD_cParameter.
|
|
|
+ * Parameters must be applied to a ZSTD_CCtx using ZSTD_CCtx_setParametersUsingCCtxParams().
|
|
|
+ * Note : when `value` is an enum, cast it to unsigned for proper type checking.
|
|
|
+ * @result : 0, or an error code (which can be tested with ZSTD_isError()).
|
|
|
+ */
|
|
|
+ZSTDLIB_API size_t ZSTD_CCtxParam_setParameter(ZSTD_CCtx_params* params, ZSTD_cParameter param, unsigned value);
|
|
|
+
|
|
|
+/*! ZSTD_CCtx_setParametersUsingCCtxParams() :
|
|
|
+ * Apply a set of ZSTD_CCtx_params to the compression context.
|
|
|
+ * This must be done before the dictionary is loaded.
|
|
|
+ * The pledgedSrcSize is treated as unknown.
|
|
|
+ * Multithreading parameters are applied only if nbThreads > 1.
|
|
|
+ */
|
|
|
+ZSTDLIB_API size_t ZSTD_CCtx_setParametersUsingCCtxParams(
|
|
|
+ ZSTD_CCtx* cctx, const ZSTD_CCtx_params* params);
|
|
|
+
|
|
|
+
|
|
|
+/*=== Advanced parameters for decompression API ===*/
|
|
|
+
|
|
|
+/* The following parameters must be set after creating a ZSTD_DCtx* (or ZSTD_DStream*) object,
|
|
|
+ * but before starting decompression of a frame.
|
|
|
+ */
|
|
|
+
|
|
|
+/*! ZSTD_DCtx_loadDictionary() :
|
|
|
+ * Create an internal DDict from dict buffer,
|
|
|
+ * to be used to decompress next frames.
|
|
|
+ * @result : 0, or an error code (which can be tested with ZSTD_isError()).
|
|
|
+ * Special : Adding a NULL (or 0-size) dictionary invalidates any previous dictionary,
|
|
|
+ * meaning "return to no-dictionary mode".
|
|
|
+ * Note 1 : `dict` content will be copied internally.
|
|
|
+ * Use ZSTD_DCtx_loadDictionary_byReference()
|
|
|
+ * to reference dictionary content instead.
|
|
|
+ * In which case, the dictionary buffer must outlive its users.
|
|
|
+ * Note 2 : Loading a dictionary involves building tables,
|
|
|
+ * which has a non-negligible impact on CPU usage and latency.
|
|
|
+ * Note 3 : Use ZSTD_DCtx_loadDictionary_advanced() to select
|
|
|
+ * how dictionary content will be interpreted and loaded.
|
|
|
+ */
|
|
|
+ZSTDLIB_API size_t ZSTD_DCtx_loadDictionary(ZSTD_DCtx* dctx, const void* dict, size_t dictSize); /* not implemented */
|
|
|
+ZSTDLIB_API size_t ZSTD_DCtx_loadDictionary_byReference(ZSTD_DCtx* dctx, const void* dict, size_t dictSize); /* not implemented */
|
|
|
+ZSTDLIB_API size_t ZSTD_DCtx_loadDictionary_advanced(ZSTD_DCtx* dctx, const void* dict, size_t dictSize, ZSTD_dictLoadMethod_e dictLoadMethod, ZSTD_dictMode_e dictMode); /* not implemented */
|
|
|
+
|
|
|
+
|
|
|
+/*! ZSTD_DCtx_refDDict() :
|
|
|
+ * Reference a prepared dictionary, to be used to decompress next frames.
|
|
|
+ * The dictionary remains active for decompression of future frames using same DCtx.
|
|
|
+ * @result : 0, or an error code (which can be tested with ZSTD_isError()).
|
|
|
+ * Note 1 : Currently, only one dictionary can be managed.
|
|
|
+ * Referencing a new dictionary effectively "discards" any previous one.
|
|
|
+ * Special : adding a NULL DDict means "return to no-dictionary mode".
|
|
|
+ * Note 2 : DDict is just referenced, its lifetime must outlive its usage from DCtx.
|
|
|
+ */
|
|
|
+ZSTDLIB_API size_t ZSTD_DCtx_refDDict(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict); /* not implemented */
|
|
|
+
|
|
|
+
|
|
|
+/*! ZSTD_DCtx_refPrefix() :
|
|
|
+ * Reference a prefix (single-usage dictionary) for next compression job.
|
|
|
+ * Prefix is **only used once**. It must be explicitly referenced before each frame.
|
|
|
+ * If there is a need to use same prefix multiple times, consider embedding it into a ZSTD_DDict instead.
|
|
|
+ * @result : 0, or an error code (which can be tested with ZSTD_isError()).
|
|
|
+ * Note 1 : Adding any prefix (including NULL) invalidates any previously set prefix or dictionary
|
|
|
+ * Note 2 : Prefix buffer is referenced. It must outlive compression job.
|
|
|
+ * Note 3 : By default, the prefix is treated as raw content (ZSTD_dm_rawContent).
|
|
|
+ * Use ZSTD_CCtx_refPrefix_advanced() to alter dictMode.
|
|
|
+ * Note 4 : Referencing a raw content prefix has almost no cpu nor memory cost.
|
|
|
+ */
|
|
|
+ZSTDLIB_API size_t ZSTD_DCtx_refPrefix(ZSTD_DCtx* dctx, const void* prefix, size_t prefixSize); /* not implemented */
|
|
|
+ZSTDLIB_API size_t ZSTD_DCtx_refPrefix_advanced(ZSTD_DCtx* dctx, const void* prefix, size_t prefixSize, ZSTD_dictMode_e dictMode); /* not implemented */
|
|
|
+
|
|
|
+
|
|
|
+/*! ZSTD_DCtx_setMaxWindowSize() :
|
|
|
+ * Refuses allocating internal buffers for frames requiring a window size larger than provided limit.
|
|
|
+ * This is useful to prevent a decoder context from reserving too much memory for itself (potential attack scenario).
|
|
|
+ * This parameter is only useful in streaming mode, since no internal buffer is allocated in direct mode.
|
|
|
+ * By default, a decompression context accepts all window sizes <= (1 << ZSTD_WINDOWLOG_MAX)
|
|
|
+ * @return : 0, or an error code (which can be tested using ZSTD_isError()).
|
|
|
+ */
|
|
|
+ZSTDLIB_API size_t ZSTD_DCtx_setMaxWindowSize(ZSTD_DCtx* dctx, size_t maxWindowSize);
|
|
|
+
|
|
|
+
|
|
|
+/*! ZSTD_DCtx_setFormat() :
|
|
|
+ * Instruct the decoder context about what kind of data to decode next.
|
|
|
+ * This instruction is mandatory to decode data without a fully-formed header,
|
|
|
+ * such ZSTD_f_zstd1_magicless for example.
|
|
|
+ * @return : 0, or an error code (which can be tested using ZSTD_isError()).
|
|
|
+ */
|
|
|
+ZSTDLIB_API size_t ZSTD_DCtx_setFormat(ZSTD_DCtx* dctx, ZSTD_format_e format);
|
|
|
+
|
|
|
+
|
|
|
+/*! ZSTD_decompress_generic() :
|
|
|
+ * Behave the same as ZSTD_decompressStream.
|
|
|
+ * Decompression parameters cannot be changed once decompression is started.
|
|
|
+ * @return : an error code, which can be tested using ZSTD_isError()
|
|
|
+ * if >0, a hint, nb of expected input bytes for next invocation.
|
|
|
+ * `0` means : a frame has just been fully decoded and flushed.
|
|
|
+ */
|
|
|
+ZSTDLIB_API size_t ZSTD_decompress_generic(ZSTD_DCtx* dctx,
|
|
|
+ ZSTD_outBuffer* output,
|
|
|
+ ZSTD_inBuffer* input);
|
|
|
+
|
|
|
+
|
|
|
+/*! ZSTD_decompress_generic_simpleArgs() :
|
|
|
+ * Same as ZSTD_decompress_generic(),
|
|
|
+ * but using only integral types as arguments.
|
|
|
+ * Argument list is larger than ZSTD_{in,out}Buffer,
|
|
|
+ * but can be helpful for binders from dynamic languages
|
|
|
+ * which have troubles handling structures containing memory pointers.
|
|
|
+ */
|
|
|
+ZSTDLIB_API size_t ZSTD_decompress_generic_simpleArgs (
|
|
|
+ ZSTD_DCtx* dctx,
|
|
|
+ void* dst, size_t dstCapacity, size_t* dstPos,
|
|
|
+ const void* src, size_t srcSize, size_t* srcPos);
|
|
|
+
|
|
|
+
|
|
|
+/*! ZSTD_DCtx_reset() :
|
|
|
+ * Return a DCtx to clean state.
|
|
|
+ * If a decompression was ongoing, any internal data not yet flushed is cancelled.
|
|
|
+ * All parameters are back to default values, including sticky ones.
|
|
|
+ * Dictionary (if any) is dropped.
|
|
|
+ * Parameters can be modified again after a reset.
|
|
|
+ */
|
|
|
+ZSTDLIB_API void ZSTD_DCtx_reset(ZSTD_DCtx* dctx);
|
|
|
+
|
|
|
+
|
|
|
+
|
|
|
+/* ============================ */
|
|
|
+/** Block level API */
|
|
|
+/* ============================ */
|
|
|
|
|
|
+/*!
|
|
|
Block functions produce and decode raw zstd blocks, without frame metadata.
|
|
|
Frame metadata cost is typically ~18 bytes, which can be non-negligible for very small blocks (< 100 bytes).
|
|
|
User will have to take in charge required information to regenerate data, such as compressed and content sizes.
|
|
@@ -1109,7 +1357,7 @@ size_t ZSTD_compress_generic_simpleArgs (
|
|
|
+ compression : any ZSTD_compressBegin*() variant, including with dictionary
|
|
|
+ decompression : any ZSTD_decompressBegin*() variant, including with dictionary
|
|
|
+ copyCCtx() and copyDCtx() can be used too
|
|
|
- - Block size is limited, it must be <= ZSTD_getBlockSize() <= ZSTD_BLOCKSIZE_MAX
|
|
|
+ - Block size is limited, it must be <= ZSTD_getBlockSize() <= ZSTD_BLOCKSIZE_MAX == 128 KB
|
|
|
+ If input is larger than a block size, it's necessary to split input data into multiple blocks
|
|
|
+ For inputs larger than a single block size, consider using the regular ZSTD_compress() instead.
|
|
|
Frame metadata is not that costly, and quickly becomes negligible as source size grows larger.
|
|
@@ -1128,7 +1376,7 @@ size_t ZSTD_compress_generic_simpleArgs (
|
|
|
ZSTDLIB_API size_t ZSTD_getBlockSize (const ZSTD_CCtx* cctx);
|
|
|
ZSTDLIB_API size_t ZSTD_compressBlock (ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);
|
|
|
ZSTDLIB_API size_t ZSTD_decompressBlock(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);
|
|
|
-ZSTDLIB_API size_t ZSTD_insertBlock(ZSTD_DCtx* dctx, const void* blockStart, size_t blockSize); /**< insert block into `dctx` history. Useful for uncompressed blocks */
|
|
|
+ZSTDLIB_API size_t ZSTD_insertBlock(ZSTD_DCtx* dctx, const void* blockStart, size_t blockSize); /**< insert uncompressed block into `dctx` history. Useful for multi-blocks decompression */
|
|
|
|
|
|
|
|
|
#endif /* ZSTD_H_ZSTD_STATIC_LINKING_ONLY */
|