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authorVsevolod Stakhov <vsevolod@highsecure.ru>2017-09-20 07:58:12 +0100
committerVsevolod Stakhov <vsevolod@highsecure.ru>2017-09-20 07:58:12 +0100
commit0050cedd31961425907fc655056ad36bb73b61fe (patch)
treeff5af69f2b56ec80a89f95cf56542c1ba696d155 /contrib/zstd/zstd.h
parent8e28ab597f8cd87358c9b5a674cfbdd789385dfb (diff)
downloadrspamd-0050cedd31961425907fc655056ad36bb73b61fe.tar.gz
rspamd-0050cedd31961425907fc655056ad36bb73b61fe.zip
[Minor] Update bundled zstd
Diffstat (limited to 'contrib/zstd/zstd.h')
-rw-r--r--contrib/zstd/zstd.h780
1 files changed, 612 insertions, 168 deletions
diff --git a/contrib/zstd/zstd.h b/contrib/zstd/zstd.h
index eef2b0b5e..ddb284299 100644
--- a/contrib/zstd/zstd.h
+++ b/contrib/zstd/zstd.h
@@ -2,27 +2,29 @@
* Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
* All rights reserved.
*
- * This source code is licensed under the BSD-style license found in the
- * LICENSE file in the root directory of this source tree. An additional grant
- * of patent rights can be found in the PATENTS file in the same directory.
+ * This source code is licensed under both the BSD-style license (found in the
+ * LICENSE file in the root directory of this source tree) and the GPLv2 (found
+ * in the COPYING file in the root directory of this source tree).
+ * You may select, at your option, one of the above-listed licenses.
*/
-
#if defined (__cplusplus)
extern "C" {
#endif
#ifndef ZSTD_H_235446
#define ZSTD_H_235446
-#define ZSTD_STATIC_LINKING_ONLY
+
/* ====== Dependency ======*/
#include <stddef.h> /* size_t */
/* ===== ZSTDLIB_API : control library symbols visibility ===== */
-#if defined(__GNUC__) && (__GNUC__ >= 4)
-# define ZSTDLIB_VISIBILITY __attribute__ ((visibility ("default")))
-#else
-# define ZSTDLIB_VISIBILITY
+#ifndef ZSTDLIB_VISIBILITY
+# if defined(__GNUC__) && (__GNUC__ >= 4)
+# define ZSTDLIB_VISIBILITY __attribute__ ((visibility ("default")))
+# else
+# define ZSTDLIB_VISIBILITY
+# endif
#endif
#if defined(ZSTD_DLL_EXPORT) && (ZSTD_DLL_EXPORT==1)
# define ZSTDLIB_API __declspec(dllexport) ZSTDLIB_VISIBILITY
@@ -36,35 +38,37 @@ extern "C" {
/*******************************************************************************************************
Introduction
- zstd, short for Zstandard, is a fast lossless compression algorithm, targeting real-time compression scenarios
- at zlib-level and better compression ratios. The zstd compression library provides in-memory compression and
- decompression functions. The library supports compression levels from 1 up to ZSTD_maxCLevel() which is 22.
+ zstd, short for Zstandard, is a fast lossless compression algorithm,
+ targeting real-time compression scenarios at zlib-level and better compression ratios.
+ The zstd compression library provides in-memory compression and decompression functions.
+ The library supports compression levels from 1 up to ZSTD_maxCLevel() which is currently 22.
Levels >= 20, labeled `--ultra`, should be used with caution, as they require more memory.
Compression can be done in:
- a single step (described as Simple API)
- a single step, reusing a context (described as Explicit memory management)
- unbounded multiple steps (described as Streaming compression)
- The compression ratio achievable on small data can be highly improved using compression with a dictionary in:
+ The compression ratio achievable on small data can be highly improved using a dictionary in:
- a single step (described as Simple dictionary API)
- a single step, reusing a dictionary (described as Fast dictionary API)
Advanced experimental functions can be accessed using #define ZSTD_STATIC_LINKING_ONLY before including zstd.h.
- These APIs shall never be used with a dynamic library.
+ Advanced experimental APIs shall never be used with a dynamic library.
They are not "stable", their definition may change in the future. Only static linking is allowed.
*********************************************************************************************************/
/*------ Version ------*/
#define ZSTD_VERSION_MAJOR 1
#define ZSTD_VERSION_MINOR 3
-#define ZSTD_VERSION_RELEASE 0
+#define ZSTD_VERSION_RELEASE 1
+
+#define ZSTD_VERSION_NUMBER (ZSTD_VERSION_MAJOR *100*100 + ZSTD_VERSION_MINOR *100 + ZSTD_VERSION_RELEASE)
+ZSTDLIB_API unsigned ZSTD_versionNumber(void); /**< useful to check dll version */
#define ZSTD_LIB_VERSION ZSTD_VERSION_MAJOR.ZSTD_VERSION_MINOR.ZSTD_VERSION_RELEASE
#define ZSTD_QUOTE(str) #str
#define ZSTD_EXPAND_AND_QUOTE(str) ZSTD_QUOTE(str)
#define ZSTD_VERSION_STRING ZSTD_EXPAND_AND_QUOTE(ZSTD_LIB_VERSION)
-
-#define ZSTD_VERSION_NUMBER (ZSTD_VERSION_MAJOR *100*100 + ZSTD_VERSION_MINOR *100 + ZSTD_VERSION_RELEASE)
-ZSTDLIB_API unsigned ZSTD_versionNumber(void); /**< library version number; to be used when checking dll version */
+ZSTDLIB_API const char* ZSTD_versionString(void); /* v1.3.0 */
/***************************************
@@ -81,38 +85,48 @@ ZSTDLIB_API size_t ZSTD_compress( void* dst, size_t dstCapacity,
/*! ZSTD_decompress() :
* `compressedSize` : must be the _exact_ size of some number of compressed and/or skippable frames.
- * `dstCapacity` is an upper bound of originalSize.
+ * `dstCapacity` is an upper bound of originalSize to regenerate.
* If user cannot imply a maximum upper bound, it's better to use streaming mode to decompress data.
* @return : the number of bytes decompressed into `dst` (<= `dstCapacity`),
* or an errorCode if it fails (which can be tested using ZSTD_isError()). */
ZSTDLIB_API size_t ZSTD_decompress( void* dst, size_t dstCapacity,
const void* src, size_t compressedSize);
-/*! ZSTD_getDecompressedSize() :
- * NOTE: This function is planned to be obsolete, in favour of ZSTD_getFrameContentSize.
- * ZSTD_getFrameContentSize functions the same way, returning the decompressed size of a single
- * frame, but distinguishes empty frames from frames with an unknown size, or errors.
- *
- * Additionally, ZSTD_findDecompressedSize can be used instead. It can handle multiple
- * concatenated frames in one buffer, and so is more general.
- * As a result however, it requires more computation and entire frames to be passed to it,
- * as opposed to ZSTD_getFrameContentSize which requires only a single frame's header.
- *
- * 'src' is the start of a zstd compressed frame.
- * @return : content size to be decompressed, as a 64-bits value _if known_, 0 otherwise.
- * note 1 : decompressed size is an optional field, that may not be present, especially in streaming mode.
- * When `return==0`, data to decompress could be any size.
+/*! ZSTD_getFrameContentSize() : v1.3.0
+ * `src` should point to the start of a ZSTD encoded frame.
+ * `srcSize` must be at least as large as the frame header.
+ * hint : any size >= `ZSTD_frameHeaderSize_max` is large enough.
+ * @return : - decompressed size of the frame in `src`, if known
+ * - ZSTD_CONTENTSIZE_UNKNOWN if the size cannot be determined
+ * - ZSTD_CONTENTSIZE_ERROR if an error occurred (e.g. invalid magic number, srcSize too small)
+ * note 1 : a 0 return value means the frame is valid but "empty".
+ * note 2 : decompressed size is an optional field, it may not be present, typically in streaming mode.
+ * When `return==ZSTD_CONTENTSIZE_UNKNOWN`, data to decompress could be any size.
* In which case, it's necessary to use streaming mode to decompress data.
- * Optionally, application can still use ZSTD_decompress() while relying on implied limits.
- * (For example, data may be necessarily cut into blocks <= 16 KB).
- * note 2 : decompressed size is always present when compression is done with ZSTD_compress()
- * note 3 : decompressed size can be very large (64-bits value),
+ * Optionally, application can rely on some implicit limit,
+ * as ZSTD_decompress() only needs an upper bound of decompressed size.
+ * (For example, data could be necessarily cut into blocks <= 16 KB).
+ * note 3 : decompressed size is always present when compression is done with ZSTD_compress()
+ * note 4 : decompressed size can be very large (64-bits value),
* potentially larger than what local system can handle as a single memory segment.
* In which case, it's necessary to use streaming mode to decompress data.
- * note 4 : If source is untrusted, decompressed size could be wrong or intentionally modified.
- * Always ensure result fits within application's authorized limits.
+ * note 5 : If source is untrusted, decompressed size could be wrong or intentionally modified.
+ * Always ensure return value fits within application's authorized limits.
* Each application can set its own limits.
- * note 5 : when `return==0`, if precise failure cause is needed, use ZSTD_getFrameParams() to know more. */
+ * note 6 : This function replaces ZSTD_getDecompressedSize() */
+#define ZSTD_CONTENTSIZE_UNKNOWN (0ULL - 1)
+#define ZSTD_CONTENTSIZE_ERROR (0ULL - 2)
+ZSTDLIB_API unsigned long long ZSTD_getFrameContentSize(const void *src, size_t srcSize);
+
+/*! ZSTD_getDecompressedSize() :
+ * NOTE: This function is now obsolete, in favor of ZSTD_getFrameContentSize().
+ * Both functions work the same way,
+ * but ZSTD_getDecompressedSize() blends
+ * "empty", "unknown" and "error" results in the same return value (0),
+ * while ZSTD_getFrameContentSize() distinguishes them.
+ *
+ * 'src' is the start of a zstd compressed frame.
+ * @return : content size to be decompressed, as a 64-bits value _if known and not empty_, 0 otherwise. */
ZSTDLIB_API unsigned long long ZSTD_getDecompressedSize(const void* src, size_t srcSize);
@@ -137,29 +151,35 @@ ZSTDLIB_API size_t ZSTD_freeCCtx(ZSTD_CCtx* cctx);
/*! ZSTD_compressCCtx() :
* Same as ZSTD_compress(), requires an allocated ZSTD_CCtx (see ZSTD_createCCtx()). */
-ZSTDLIB_API size_t ZSTD_compressCCtx(ZSTD_CCtx* ctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize, int compressionLevel);
+ZSTDLIB_API size_t ZSTD_compressCCtx(ZSTD_CCtx* ctx,
+ void* dst, size_t dstCapacity,
+ const void* src, size_t srcSize,
+ int compressionLevel);
/*= Decompression context
* When decompressing many times,
- * it is recommended to allocate a context just once, and re-use it for each successive compression operation.
+ * it is recommended to allocate a context only once,
+ * and re-use it for each successive compression operation.
* This will make workload friendlier for system's memory.
- * Use one context per thread for parallel execution in multi-threaded environments. */
+ * Use one context per thread for parallel execution. */
typedef struct ZSTD_DCtx_s ZSTD_DCtx;
ZSTDLIB_API ZSTD_DCtx* ZSTD_createDCtx(void);
ZSTDLIB_API size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx);
/*! ZSTD_decompressDCtx() :
- * Same as ZSTD_decompress(), requires an allocated ZSTD_DCtx (see ZSTD_createDCtx()). */
-ZSTDLIB_API size_t ZSTD_decompressDCtx(ZSTD_DCtx* ctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);
+ * Same as ZSTD_decompress(), requires an allocated ZSTD_DCtx (see ZSTD_createDCtx()) */
+ZSTDLIB_API size_t ZSTD_decompressDCtx(ZSTD_DCtx* ctx,
+ void* dst, size_t dstCapacity,
+ const void* src, size_t srcSize);
/**************************
* Simple dictionary API
***************************/
/*! ZSTD_compress_usingDict() :
-* Compression using a predefined Dictionary (see dictBuilder/zdict.h).
-* Note : This function loads the dictionary, resulting in significant startup delay.
-* Note : When `dict == NULL || dictSize < 8` no dictionary is used. */
+ * Compression using a predefined Dictionary (see dictBuilder/zdict.h).
+ * Note : This function loads the dictionary, resulting in significant startup delay.
+ * Note : When `dict == NULL || dictSize < 8` no dictionary is used. */
ZSTDLIB_API size_t ZSTD_compress_usingDict(ZSTD_CCtx* ctx,
void* dst, size_t dstCapacity,
const void* src, size_t srcSize,
@@ -167,30 +187,31 @@ ZSTDLIB_API size_t ZSTD_compress_usingDict(ZSTD_CCtx* ctx,
int compressionLevel);
/*! ZSTD_decompress_usingDict() :
-* Decompression using a predefined Dictionary (see dictBuilder/zdict.h).
-* Dictionary must be identical to the one used during compression.
-* Note : This function loads the dictionary, resulting in significant startup delay.
-* Note : When `dict == NULL || dictSize < 8` no dictionary is used. */
+ * Decompression using a predefined Dictionary (see dictBuilder/zdict.h).
+ * Dictionary must be identical to the one used during compression.
+ * Note : This function loads the dictionary, resulting in significant startup delay.
+ * Note : When `dict == NULL || dictSize < 8` no dictionary is used. */
ZSTDLIB_API size_t ZSTD_decompress_usingDict(ZSTD_DCtx* dctx,
void* dst, size_t dstCapacity,
const void* src, size_t srcSize,
const void* dict,size_t dictSize);
-/****************************
-* Fast dictionary API
-****************************/
+/**********************************
+ * Bulk processing dictionary API
+ *********************************/
typedef struct ZSTD_CDict_s ZSTD_CDict;
/*! ZSTD_createCDict() :
-* When compressing multiple messages / blocks with the same dictionary, it's recommended to load it just once.
-* ZSTD_createCDict() will create a digested dictionary, ready to start future compression operations without startup delay.
-* ZSTD_CDict can be created once and used by multiple threads concurrently, as its usage is read-only.
-* `dictBuffer` can be released after ZSTD_CDict creation, as its content is copied within CDict */
-ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict(const void* dictBuffer, size_t dictSize, int compressionLevel);
+ * When compressing multiple messages / blocks with the same dictionary, it's recommended to load it just once.
+ * ZSTD_createCDict() will create a digested dictionary, ready to start future compression operations without startup delay.
+ * ZSTD_CDict can be created once and shared by multiple threads concurrently, since its usage is read-only.
+ * `dictBuffer` can be released after ZSTD_CDict creation, since its content is copied within CDict */
+ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict(const void* dictBuffer, size_t dictSize,
+ int compressionLevel);
/*! ZSTD_freeCDict() :
-* Function frees memory allocated by ZSTD_createCDict(). */
+ * Function frees memory allocated by ZSTD_createCDict(). */
ZSTDLIB_API size_t ZSTD_freeCDict(ZSTD_CDict* CDict);
/*! ZSTD_compress_usingCDict() :
@@ -207,17 +228,17 @@ ZSTDLIB_API size_t ZSTD_compress_usingCDict(ZSTD_CCtx* cctx,
typedef struct ZSTD_DDict_s ZSTD_DDict;
/*! ZSTD_createDDict() :
-* Create a digested dictionary, ready to start decompression operation without startup delay.
-* dictBuffer can be released after DDict creation, as its content is copied inside DDict */
+ * Create a digested dictionary, ready to start decompression operation without startup delay.
+ * dictBuffer can be released after DDict creation, as its content is copied inside DDict */
ZSTDLIB_API ZSTD_DDict* ZSTD_createDDict(const void* dictBuffer, size_t dictSize);
/*! ZSTD_freeDDict() :
-* Function frees memory allocated with ZSTD_createDDict() */
+ * Function frees memory allocated with ZSTD_createDDict() */
ZSTDLIB_API size_t ZSTD_freeDDict(ZSTD_DDict* ddict);
/*! ZSTD_decompress_usingDDict() :
-* Decompression using a digested Dictionary.
-* Faster startup than ZSTD_decompress_usingDict(), recommended when same dictionary is used multiple times. */
+ * Decompression using a digested Dictionary.
+ * Faster startup than ZSTD_decompress_usingDict(), recommended when same dictionary is used multiple times. */
ZSTDLIB_API size_t ZSTD_decompress_usingDDict(ZSTD_DCtx* dctx,
void* dst, size_t dstCapacity,
const void* src, size_t srcSize,
@@ -274,15 +295,17 @@ typedef struct ZSTD_outBuffer_s {
* ZSTD_endStream() instructs to finish a frame.
* It will perform a flush and write frame epilogue.
* The epilogue is required for decoders to consider a frame completed.
-* Similar to ZSTD_flushStream(), it may not be able to flush the full content if `output->size` is too small.
+* ZSTD_endStream() may not be able to flush full data if `output->size` is too small.
* In which case, call again ZSTD_endStream() to complete the flush.
-* @return : nb of bytes still present within internal buffer (0 if it's empty, hence compression completed)
+* @return : 0 if frame fully completed and fully flushed,
+ or >0 if some data is still present within internal buffer
+ (value is minimum size estimation for remaining data to flush, but it could be more)
* or an error code, which can be tested using ZSTD_isError().
*
* *******************************************************************/
-typedef ZSTD_CCtx ZSTD_CStream; /**< CCtx and CStream are effectively same object */
- /* Continue due distinghish them for compatibility with versions <= v1.2.0 */
+typedef ZSTD_CCtx ZSTD_CStream; /**< CCtx and CStream are now effectively same object (>= v1.3.0) */
+ /* Continue to distinguish them for compatibility with versions <= v1.2.0 */
/*===== ZSTD_CStream management functions =====*/
ZSTDLIB_API ZSTD_CStream* ZSTD_createCStream(void);
ZSTDLIB_API size_t ZSTD_freeCStream(ZSTD_CStream* zcs);
@@ -320,7 +343,8 @@ ZSTDLIB_API size_t ZSTD_CStreamOutSize(void); /**< recommended size for output
* The return value is a suggested next input size (a hint to improve latency) that will never load more than the current frame.
* *******************************************************************************/
-typedef struct ZSTD_DStream_s ZSTD_DStream;
+typedef ZSTD_DCtx ZSTD_DStream; /**< DCtx and DStream are now effectively same object (>= v1.3.0) */
+ /* Continue to distinguish them for compatibility with versions <= v1.2.0 */
/*===== ZSTD_DStream management functions =====*/
ZSTDLIB_API ZSTD_DStream* ZSTD_createDStream(void);
ZSTDLIB_API size_t ZSTD_freeDStream(ZSTD_DStream* zds);
@@ -335,20 +359,22 @@ ZSTDLIB_API size_t ZSTD_DStreamOutSize(void); /*!< recommended size for output
#endif /* ZSTD_H_235446 */
-#if defined(ZSTD_STATIC_LINKING_ONLY) && !defined(ZSTD_H_ZSTD_STATIC_LINKING_ONLY)
-#define ZSTD_H_ZSTD_STATIC_LINKING_ONLY
/****************************************************************************************
* START OF ADVANCED AND EXPERIMENTAL FUNCTIONS
* The definitions in this section are considered experimental.
- * They should never be used with a dynamic library, as they may change in the future.
- * They are provided for advanced usages.
+ * They should never be used with a dynamic library, as prototypes may change in the future.
+ * They are provided for advanced scenarios.
* Use them only in association with static linking.
* ***************************************************************************************/
+#if defined(ZSTD_STATIC_LINKING_ONLY) && !defined(ZSTD_H_ZSTD_STATIC_LINKING_ONLY)
+#define ZSTD_H_ZSTD_STATIC_LINKING_ONLY
+
/* --- 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
@@ -365,17 +391,21 @@ ZSTDLIB_API size_t ZSTD_DStreamOutSize(void); /*!< recommended size for output
#define ZSTD_SEARCHLENGTH_MIN 3 /* only for ZSTD_btopt, other strategies are limited to 4 */
#define ZSTD_TARGETLENGTH_MIN 4
#define ZSTD_TARGETLENGTH_MAX 999
+#define ZSTD_LDM_MINMATCH_MIN 4
+#define ZSTD_LDM_MINMATCH_MAX 4096
+#define ZSTD_LDM_BUCKETSIZELOG_MAX 8
#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_min = ZSTD_FRAMEHEADERSIZE_MIN;
+static const size_t ZSTD_frameHeaderSize_prefix = 5; /* minimum input size to know frame header size */
static const size_t ZSTD_frameHeaderSize_max = ZSTD_FRAMEHEADERSIZE_MAX;
+static const size_t ZSTD_frameHeaderSize_min = ZSTD_FRAMEHEADERSIZE_MIN;
static const size_t ZSTD_skippableHeaderSize = 8; /* magic number + skippable frame length */
/*--- Advanced types ---*/
-typedef enum { ZSTD_fast, ZSTD_dfast, ZSTD_greedy, ZSTD_lazy, ZSTD_lazy2, ZSTD_btlazy2, ZSTD_btopt, ZSTD_btultra } ZSTD_strategy; /* from faster to stronger */
+typedef enum { ZSTD_fast=1, ZSTD_dfast, ZSTD_greedy, ZSTD_lazy, ZSTD_lazy2,
+ ZSTD_btlazy2, ZSTD_btopt, ZSTD_btultra } ZSTD_strategy; /* from faster to stronger */
typedef struct {
unsigned windowLog; /**< largest match distance : larger == more compression, more memory needed during decompression */
@@ -398,17 +428,15 @@ typedef struct {
ZSTD_frameParameters fParams;
} ZSTD_parameters;
-typedef struct {
- unsigned long long frameContentSize;
- unsigned windowSize;
- unsigned dictID;
- unsigned checksumFlag;
-} ZSTD_frameHeader;
+typedef struct ZSTD_CCtx_params_s ZSTD_CCtx_params;
/*= Custom memory allocation functions */
typedef void* (*ZSTD_allocFunction) (void* opaque, size_t size);
typedef void (*ZSTD_freeFunction) (void* opaque, void* address);
typedef struct { ZSTD_allocFunction customAlloc; ZSTD_freeFunction customFree; void* opaque; } ZSTD_customMem;
+/* use this constant to defer to stdlib's functions */
+static const ZSTD_customMem ZSTD_defaultCMem = { NULL, NULL, NULL };
+
/***************************************
* Frame size functions
@@ -417,26 +445,15 @@ typedef struct { ZSTD_allocFunction customAlloc; ZSTD_freeFunction customFree; v
/*! ZSTD_findFrameCompressedSize() :
* `src` should point to the start of a ZSTD encoded frame or skippable frame
* `srcSize` must be at least as large as the frame
- * @return : the compressed size of the frame pointed to by `src`,
+ * @return : the compressed size of the first frame starting at `src`,
* suitable to pass to `ZSTD_decompress` or similar,
- * or an error code if given invalid input. */
+ * or an error code if input is invalid */
ZSTDLIB_API size_t ZSTD_findFrameCompressedSize(const void* src, size_t srcSize);
-/*! ZSTD_getFrameContentSize() :
- * `src` should point to the start of a ZSTD encoded frame.
- * `srcSize` must be at least as large as the frame header.
- * A value >= `ZSTD_frameHeaderSize_max` is guaranteed to be large enough.
- * @return : - decompressed size of the frame pointed to be `src` if known
- * - ZSTD_CONTENTSIZE_UNKNOWN if the size cannot be determined
- * - ZSTD_CONTENTSIZE_ERROR if an error occurred (e.g. invalid magic number, srcSize too small) */
-#define ZSTD_CONTENTSIZE_UNKNOWN (0ULL - 1)
-#define ZSTD_CONTENTSIZE_ERROR (0ULL - 2)
-ZSTDLIB_API unsigned long long ZSTD_getFrameContentSize(const void *src, size_t srcSize);
-
/*! ZSTD_findDecompressedSize() :
* `src` should point the start of a series of ZSTD encoded and/or skippable frames
* `srcSize` must be the _exact_ size of this series
- * (i.e. there should be a frame boundary exactly `srcSize` bytes after `src`)
+ * (i.e. there should be a frame boundary exactly at `srcSize` bytes after `src`)
* @return : - decompressed size of all data in all successive frames
* - if the decompressed size cannot be determined: ZSTD_CONTENTSIZE_UNKNOWN
* - if an error occurred: ZSTD_CONTENTSIZE_ERROR
@@ -444,8 +461,6 @@ ZSTDLIB_API unsigned long long ZSTD_getFrameContentSize(const void *src, size_t
* note 1 : decompressed size is an optional field, that may not be present, especially in streaming mode.
* When `return==ZSTD_CONTENTSIZE_UNKNOWN`, data to decompress could be any size.
* In which case, it's necessary to use streaming mode to decompress data.
- * Optionally, application can still use ZSTD_decompress() while relying on implied limits.
- * (For example, data may be necessarily cut into blocks <= 16 KB).
* note 2 : decompressed size is always present when compression is done with ZSTD_compress()
* note 3 : decompressed size can be very large (64-bits value),
* potentially larger than what local system can handle as a single memory segment.
@@ -454,10 +469,16 @@ ZSTDLIB_API unsigned long long ZSTD_getFrameContentSize(const void *src, size_t
* Always ensure result fits within application's authorized limits.
* Each application can set its own limits.
* note 5 : ZSTD_findDecompressedSize handles multiple frames, and so it must traverse the input to
- * read each contained frame header. This is efficient as most of the data is skipped,
+ * read each contained frame header. This is fast as most of the data is skipped,
* however it does mean that all frame data must be present and valid. */
ZSTDLIB_API unsigned long long ZSTD_findDecompressedSize(const void* src, size_t srcSize);
+/*! ZSTD_frameHeaderSize() :
+* `src` should point to the start of a ZSTD frame
+* `srcSize` must be >= ZSTD_frameHeaderSize_prefix.
+* @return : size of the Frame Header */
+ZSTDLIB_API size_t ZSTD_frameHeaderSize(const void* src, size_t srcSize);
+
/***************************************
* Context memory usage
@@ -475,23 +496,50 @@ ZSTDLIB_API size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict);
/*! ZSTD_estimate*() :
* These functions make it possible to estimate memory usage
- * of a future target object, before its allocation,
- * given a set of parameters, which vary depending on target object.
- * The objective is to guide decision before allocation. */
-ZSTDLIB_API size_t ZSTD_estimateCCtxSize(ZSTD_compressionParameters cParams);
+ * of a future {D,C}Ctx, before its creation.
+ * ZSTD_estimateCCtxSize() will provide a budget large enough for any compression level up to selected one.
+ * It will also consider src size to be arbitrarily "large", which is worst case.
+ * If srcSize is known to always be small, ZSTD_estimateCCtxSize_advanced_usingCParams() can provide a tighter estimation.
+ * ZSTD_estimateCCtxSize_advanced_usingCParams() can be used in tandem with ZSTD_getCParams() to create cParams from compressionLevel.
+ * ZSTD_estimateCCtxSize_advanced_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.
+ * Note : CCtx estimation is only correct for single-threaded compression */
+ZSTDLIB_API size_t ZSTD_estimateCCtxSize(int compressionLevel);
+ZSTDLIB_API size_t ZSTD_estimateCCtxSize_advanced_usingCParams(ZSTD_compressionParameters cParams);
+ZSTDLIB_API size_t ZSTD_estimateCCtxSize_advanced_usingCCtxParams(const ZSTD_CCtx_params* params);
ZSTDLIB_API size_t ZSTD_estimateDCtxSize(void);
-/*! ZSTD_estimate?StreamSize() :
+/*! ZSTD_estimateCStreamSize() :
+ * ZSTD_estimateCStreamSize() will provide a budget large enough for any compression level up to selected one.
+ * It will also consider src size to be arbitrarily "large", which is worst case.
+ * If srcSize is known to always be small, ZSTD_estimateCStreamSize_advanced_usingCParams() can provide a tighter estimation.
+ * ZSTD_estimateCStreamSize_advanced_usingCParams() can be used in tandem with ZSTD_getCParams() to create cParams from compressionLevel.
+ * ZSTD_estimateCStreamSize_advanced_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.
+ * Note : CStream estimation is only correct for single-threaded compression.
+ * ZSTD_DStream memory budget depends on window Size.
+ * This information can be passed manually, using ZSTD_estimateDStreamSize,
+ * or deducted from a valid frame Header, using ZSTD_estimateDStreamSize_fromFrame();
* Note : if streaming is init with function ZSTD_init?Stream_usingDict(),
- * an internal ?Dict will be created, which size is not estimated.
- * In this case, get additional size by using ZSTD_estimate?DictSize */
-ZSTDLIB_API size_t ZSTD_estimateCStreamSize(ZSTD_compressionParameters cParams);
-ZSTDLIB_API size_t ZSTD_estimateDStreamSize(ZSTD_frameHeader fHeader);
+ * an internal ?Dict will be created, which additional size is not estimated here.
+ * In this case, get total size by adding ZSTD_estimate?DictSize */
+ZSTDLIB_API size_t ZSTD_estimateCStreamSize(int compressionLevel);
+ZSTDLIB_API size_t ZSTD_estimateCStreamSize_advanced_usingCParams(ZSTD_compressionParameters cParams);
+ZSTDLIB_API size_t ZSTD_estimateCStreamSize_advanced_usingCCtxParams(const ZSTD_CCtx_params* params);
+ZSTDLIB_API size_t ZSTD_estimateDStreamSize(size_t windowSize);
+ZSTDLIB_API size_t ZSTD_estimateDStreamSize_fromFrame(const void* src, size_t srcSize);
+
+typedef enum {
+ ZSTD_dlm_byCopy = 0, /* Copy dictionary content internally. */
+ ZSTD_dlm_byRef, /* Reference dictionary content -- the dictionary buffer must outlives its users. */
+} ZSTD_dictLoadMethod_e;
/*! ZSTD_estimate?DictSize() :
- * Note : if dictionary is created "byReference", reduce estimation by dictSize */
-ZSTDLIB_API size_t ZSTD_estimateCDictSize(ZSTD_compressionParameters cParams, size_t dictSize);
-ZSTDLIB_API size_t ZSTD_estimateDDictSize(size_t dictSize);
+ * ZSTD_estimateCDictSize() will bet that src size is relatively "small", and content is copied, like ZSTD_createCDict().
+ * ZSTD_estimateCStreamSize_advanced_usingCParams() makes it possible to control precisely compression parameters, like ZSTD_createCDict_advanced().
+ * Note : dictionary created by reference using ZSTD_dlm_byRef are smaller
+ */
+ZSTDLIB_API size_t ZSTD_estimateCDictSize(size_t dictSize, int compressionLevel);
+ZSTDLIB_API size_t ZSTD_estimateCDictSize_advanced(size_t dictSize, ZSTD_compressionParameters cParams, ZSTD_dictLoadMethod_e dictLoadMethod);
+ZSTDLIB_API size_t ZSTD_estimateDDictSize(size_t dictSize, ZSTD_dictLoadMethod_e dictLoadMethod);
/***************************************
@@ -501,14 +549,23 @@ ZSTDLIB_API size_t ZSTD_estimateDDictSize(size_t dictSize);
* Create a ZSTD compression context using external alloc and free functions */
ZSTDLIB_API ZSTD_CCtx* ZSTD_createCCtx_advanced(ZSTD_customMem customMem);
-typedef enum {
- ZSTD_p_forceWindow, /* Force back-references to remain < windowSize, even when referencing Dictionary content (default:0) */
- ZSTD_p_forceRawDict /* Force loading dictionary in "content-only" mode (no header analysis) */
-} ZSTD_CCtxParameter;
-/*! ZSTD_setCCtxParameter() :
- * Set advanced parameters, selected through enum ZSTD_CCtxParameter
- * @result : 0, or an error code (which can be tested with ZSTD_isError()) */
-ZSTDLIB_API size_t ZSTD_setCCtxParameter(ZSTD_CCtx* cctx, ZSTD_CCtxParameter param, unsigned value);
+/*! ZSTD_initStaticCCtx() : initialize a fixed-size zstd compression context
+ * workspace: The memory area to emplace the context into.
+ * Provided pointer must 8-bytes aligned.
+ * It must outlive context usage.
+ * workspaceSize: Use ZSTD_estimateCCtxSize() or ZSTD_estimateCStreamSize()
+ * to determine how large workspace must be to support scenario.
+ * @return : pointer to ZSTD_CCtx*, or NULL if error (size too small)
+ * Note : zstd will never resize nor malloc() when using a static cctx.
+ * If it needs more memory than available, it will simply error out.
+ * Note 2 : there is no corresponding "free" function.
+ * Since workspace was allocated externally, it must be freed externally too.
+ * Limitation 1 : currently not compatible with internal CDict creation, such as
+ * ZSTD_CCtx_loadDictionary() or ZSTD_initCStream_usingDict().
+ * Limitation 2 : currently not compatible with multi-threading
+ */
+ZSTDLIB_API ZSTD_CCtx* ZSTD_initStaticCCtx(void* workspace, size_t workspaceSize);
+
/*! ZSTD_createCDict_byReference() :
* Create a digested dictionary for compression
@@ -516,10 +573,36 @@ ZSTDLIB_API size_t ZSTD_setCCtxParameter(ZSTD_CCtx* cctx, ZSTD_CCtxParameter par
* It is important that dictBuffer outlives CDict, it must remain read accessible throughout the lifetime of CDict */
ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict_byReference(const void* dictBuffer, size_t dictSize, int compressionLevel);
+typedef enum { ZSTD_dm_auto=0, /* dictionary is "full" if it starts with ZSTD_MAGIC_DICTIONARY, otherwise it is "rawContent" */
+ 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, unsigned byReference,
- ZSTD_compressionParameters cParams, ZSTD_customMem customMem);
+ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict_advanced(const void* dict, size_t dictSize,
+ ZSTD_dictLoadMethod_e dictLoadMethod,
+ ZSTD_dictMode_e dictMode,
+ ZSTD_compressionParameters cParams,
+ ZSTD_customMem customMem);
+
+/*! ZSTD_initStaticCDict_advanced() :
+ * Generate a digested dictionary in provided memory area.
+ * workspace: The memory area to emplace the dictionary into.
+ * Provided pointer must 8-bytes aligned.
+ * It must outlive dictionary usage.
+ * workspaceSize: Use ZSTD_estimateCDictSize()
+ * to determine how large workspace must be.
+ * cParams : use ZSTD_getCParams() to transform a compression level
+ * into its relevants cParams.
+ * @return : pointer to ZSTD_CDict*, or NULL if error (size too small)
+ * Note : there is no corresponding "free" function.
+ * Since workspace was allocated externally, it must be freed externally.
+ */
+ZSTDLIB_API ZSTD_CDict* ZSTD_initStaticCDict(
+ void* workspace, size_t workspaceSize,
+ const void* dict, size_t dictSize,
+ ZSTD_dictLoadMethod_e dictLoadMethod, ZSTD_dictMode_e dictMode,
+ ZSTD_compressionParameters cParams);
/*! ZSTD_getCParams() :
* @return ZSTD_compressionParameters structure for a selected compression level and estimated srcSize.
@@ -536,8 +619,8 @@ ZSTDLIB_API ZSTD_parameters ZSTD_getParams(int compressionLevel, unsigned long l
ZSTDLIB_API size_t ZSTD_checkCParams(ZSTD_compressionParameters params);
/*! ZSTD_adjustCParams() :
-* optimize params for a given `srcSize` and `dictSize`.
-* both values are optional, select `0` if unknown. */
+ * optimize params for a given `srcSize` and `dictSize`.
+ * both values are optional, select `0` if unknown. */
ZSTDLIB_API ZSTD_compressionParameters ZSTD_adjustCParams(ZSTD_compressionParameters cPar, unsigned long long srcSize, size_t dictSize);
/*! ZSTD_compress_advanced() :
@@ -569,16 +652,50 @@ ZSTDLIB_API unsigned ZSTD_isFrame(const void* buffer, size_t size);
* Create a ZSTD decompression context using external alloc and free functions */
ZSTDLIB_API ZSTD_DCtx* ZSTD_createDCtx_advanced(ZSTD_customMem customMem);
+/*! ZSTD_initStaticDCtx() : initialize a fixed-size zstd decompression context
+ * workspace: The memory area to emplace the context into.
+ * Provided pointer must 8-bytes aligned.
+ * It must outlive context usage.
+ * workspaceSize: Use ZSTD_estimateDCtxSize() or ZSTD_estimateDStreamSize()
+ * to determine how large workspace must be to support scenario.
+ * @return : pointer to ZSTD_DCtx*, or NULL if error (size too small)
+ * Note : zstd will never resize nor malloc() when using a static dctx.
+ * If it needs more memory than available, it will simply error out.
+ * Note 2 : static dctx is incompatible with legacy support
+ * Note 3 : there is no corresponding "free" function.
+ * Since workspace was allocated externally, it must be freed externally.
+ * Limitation : currently not compatible with internal DDict creation,
+ * such as ZSTD_initDStream_usingDict().
+ */
+ZSTDLIB_API ZSTD_DCtx* ZSTD_initStaticDCtx(void* workspace, size_t workspaceSize);
+
/*! ZSTD_createDDict_byReference() :
* Create a digested dictionary, ready to start decompression operation without startup delay.
- * Dictionary content is simply referenced, and therefore stays in dictBuffer.
- * It is important that dictBuffer outlives DDict, it must remain read accessible throughout the lifetime of DDict */
+ * Dictionary content is referenced, and therefore stays in dictBuffer.
+ * It is important that dictBuffer outlives DDict,
+ * it must remain read accessible throughout the lifetime of DDict */
ZSTDLIB_API ZSTD_DDict* ZSTD_createDDict_byReference(const void* dictBuffer, size_t dictSize);
/*! ZSTD_createDDict_advanced() :
* Create a ZSTD_DDict using external alloc and free, optionally by reference */
ZSTDLIB_API ZSTD_DDict* ZSTD_createDDict_advanced(const void* dict, size_t dictSize,
- unsigned byReference, ZSTD_customMem customMem);
+ ZSTD_dictLoadMethod_e dictLoadMethod,
+ ZSTD_customMem customMem);
+
+/*! ZSTD_initStaticDDict() :
+ * Generate a digested dictionary in provided memory area.
+ * workspace: The memory area to emplace the dictionary into.
+ * Provided pointer must 8-bytes aligned.
+ * It must outlive dictionary usage.
+ * workspaceSize: Use ZSTD_estimateDDictSize()
+ * to determine how large workspace must be.
+ * @return : pointer to ZSTD_DDict*, or NULL if error (size too small)
+ * Note : there is no corresponding "free" function.
+ * Since workspace was allocated externally, it must be freed externally.
+ */
+ZSTDLIB_API ZSTD_DDict* ZSTD_initStaticDDict(void* workspace, size_t workspaceSize,
+ const void* dict, size_t dictSize,
+ ZSTD_dictLoadMethod_e dictLoadMethod);
/*! ZSTD_getDictID_fromDict() :
* Provides the dictID stored within dictionary.
@@ -601,7 +718,7 @@ ZSTDLIB_API unsigned ZSTD_getDictID_fromDDict(const ZSTD_DDict* ddict);
* Note : this use case also happens when using a non-conformant dictionary.
* - `srcSize` is too small, and as a result, the frame header could not be decoded (only possible if `srcSize < ZSTD_FRAMEHEADERSIZE_MAX`).
* - This is not a Zstandard frame.
- * When identifying the exact failure cause, it's possible to use ZSTD_getFrameParams(), which will provide a more precise error code. */
+ * When identifying the exact failure cause, it's possible to use ZSTD_getFrameHeader(), which will provide a more precise error code. */
ZSTDLIB_API unsigned ZSTD_getDictID_fromFrame(const void* src, size_t srcSize);
@@ -611,12 +728,13 @@ ZSTDLIB_API unsigned ZSTD_getDictID_fromFrame(const void* src, size_t srcSize);
/*===== Advanced Streaming compression functions =====*/
ZSTDLIB_API ZSTD_CStream* ZSTD_createCStream_advanced(ZSTD_customMem customMem);
+ZSTDLIB_API ZSTD_CStream* ZSTD_initStaticCStream(void* workspace, size_t workspaceSize); /**< same as ZSTD_initStaticCCtx() */
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. This result in the creation of an internal CDict */
+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.*/
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 */
+ 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. */
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 */
-ZSTDLIB_API size_t ZSTD_initCStream_usingCDict_advanced(ZSTD_CStream* zcs, const ZSTD_CDict* cdict, unsigned long long pledgedSrcSize, ZSTD_frameParameters fParams); /**< same as ZSTD_initCStream_usingCDict(), with control over frame parameters */
+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 */
/*! ZSTD_resetCStream() :
* start a new compression job, using same parameters from previous job.
@@ -631,6 +749,7 @@ ZSTDLIB_API size_t ZSTD_resetCStream(ZSTD_CStream* zcs, unsigned long long pledg
/*===== Advanced Streaming decompression functions =====*/
typedef enum { DStream_p_maxWindowSize } ZSTD_DStreamParameter_e;
ZSTDLIB_API ZSTD_DStream* ZSTD_createDStream_advanced(ZSTD_customMem customMem);
+ZSTDLIB_API ZSTD_DStream* ZSTD_initStaticDStream(void* workspace, size_t workspaceSize); /**< same as ZSTD_initStaticDCtx() */
ZSTDLIB_API size_t ZSTD_setDStreamParameter(ZSTD_DStream* zds, ZSTD_DStreamParameter_e paramType, unsigned paramValue);
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 */
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 */
@@ -688,7 +807,6 @@ ZSTDLIB_API size_t ZSTD_compressContinue(ZSTD_CCtx* cctx, void* dst, size_t dstC
ZSTDLIB_API size_t ZSTD_compressEnd(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);
-
/*-
Buffer-less streaming decompression (synchronous mode)
@@ -696,38 +814,54 @@ ZSTDLIB_API size_t ZSTD_compressEnd(ZSTD_CCtx* cctx, void* dst, size_t dstCapaci
Use ZSTD_createDCtx() / ZSTD_freeDCtx() to manage it.
A ZSTD_DCtx object can be re-used multiple times.
- First typical operation is to retrieve frame parameters, using ZSTD_getFrameParams().
- It fills a ZSTD_frameParams structure which provide important information to correctly decode the frame,
- such as the minimum rolling buffer size to allocate to decompress data (`windowSize`),
- and the dictionary ID used.
- (Note : content size is optional, it may not be present. 0 means : content size unknown).
- Note that these values could be wrong, either because of data malformation, or because an attacker is spoofing deliberate false information.
- As a consequence, check that values remain within valid application range, especially `windowSize`, before allocation.
- Each application can set its own limit, depending on local restrictions. For extended interoperability, it is recommended to support at least 8 MB.
- Frame parameters are extracted from the beginning of the compressed frame.
- Data fragment must be large enough to ensure successful decoding, typically `ZSTD_frameHeaderSize_max` bytes.
- @result : 0 : successful decoding, the `ZSTD_frameParams` structure is correctly filled.
+ First typical operation is to retrieve frame parameters, using ZSTD_getFrameHeader().
+ Frame header is extracted from the beginning of compressed frame, so providing only the frame's beginning is enough.
+ Data fragment must be large enough to ensure successful decoding.
+ `ZSTD_frameHeaderSize_max` bytes is guaranteed to always be large enough.
+ @result : 0 : successful decoding, the `ZSTD_frameHeader` structure is correctly filled.
>0 : `srcSize` is too small, please provide at least @result bytes on next attempt.
errorCode, which can be tested using ZSTD_isError().
- Start decompression, with ZSTD_decompressBegin() or ZSTD_decompressBegin_usingDict().
- Alternatively, you can copy a prepared context, using ZSTD_copyDCtx().
+ It fills a ZSTD_frameHeader structure with important information to correctly decode the frame,
+ such as the dictionary ID, content size, or maximum back-reference distance (`windowSize`).
+ Note that these values could be wrong, either because of data corruption, or because a 3rd party deliberately spoofs false information.
+ As a consequence, check that values remain within valid application range.
+ For example, do not allocate memory blindly, check that `windowSize` is within expectation.
+ Each application can set its own limits, depending on local restrictions.
+ For extended interoperability, it is recommended to support `windowSize` of at least 8 MB.
+
+ ZSTD_decompressContinue() needs previous data blocks during decompression, up to `windowSize` bytes.
+ ZSTD_decompressContinue() is very sensitive to contiguity,
+ if 2 blocks don't follow each other, make sure that either the compressor breaks contiguity at the same place,
+ or that previous contiguous segment is large enough to properly handle maximum back-reference distance.
+ There are multiple ways to guarantee this condition.
+
+ The most memory efficient way is to use a round buffer of sufficient size.
+ Sufficient size is determined by invoking ZSTD_decodingBufferSize_min(),
+ which can @return an error code if required value is too large for current system (in 32-bits mode).
+ In a round buffer methodology, ZSTD_decompressContinue() decompresses each block next to previous one,
+ up to the moment there is not enough room left in the buffer to guarantee decoding another full block,
+ which maximum size is provided in `ZSTD_frameHeader` structure, field `blockSizeMax`.
+ At which point, decoding can resume from the beginning of the buffer.
+ Note that already decoded data stored in the buffer should be flushed before being overwritten.
+
+ There are alternatives possible, for example using two or more buffers of size `windowSize` each, though they consume more memory.
+
+ Finally, if you control the compression process, you can also ignore all buffer size rules,
+ as long as the encoder and decoder progress in "lock-step",
+ aka use exactly the same buffer sizes, break contiguity at the same place, etc.
+
+ Once buffers are setup, start decompression, with ZSTD_decompressBegin().
+ If decompression requires a dictionary, use ZSTD_decompressBegin_usingDict() or ZSTD_decompressBegin_usingDDict().
Then use ZSTD_nextSrcSizeToDecompress() and ZSTD_decompressContinue() alternatively.
ZSTD_nextSrcSizeToDecompress() tells how many bytes to provide as 'srcSize' to ZSTD_decompressContinue().
ZSTD_decompressContinue() requires this _exact_ amount of bytes, or it will fail.
- @result of ZSTD_decompressContinue() is the number of bytes regenerated within 'dst' (necessarily <= dstCapacity).
- It can be zero, which is not an error; it just means ZSTD_decompressContinue() has decoded some metadata item.
+ @result of ZSTD_decompressContinue() is the number of bytes regenerated within 'dst' (necessarily <= dstCapacity).
+ It can be zero : it just means ZSTD_decompressContinue() has decoded some metadata item.
It can also be an error code, which can be tested with ZSTD_isError().
- ZSTD_decompressContinue() needs previous data blocks during decompression, up to `windowSize`.
- They should preferably be located contiguously, prior to current block.
- Alternatively, a round buffer of sufficient size is also possible. Sufficient size is determined by frame parameters.
- ZSTD_decompressContinue() is very sensitive to contiguity,
- if 2 blocks don't follow each other, make sure that either the compressor breaks contiguity at the same place,
- or that previous contiguous segment is large enough to properly handle maximum back-reference.
-
A frame is fully decoded when ZSTD_nextSrcSizeToDecompress() returns zero.
Context can then be reset to start a new decompression.
@@ -737,28 +871,337 @@ ZSTDLIB_API size_t ZSTD_compressEnd(ZSTD_CCtx* cctx, void* dst, size_t dstCapaci
== Special case : skippable frames ==
Skippable frames allow integration of user-defined data into a flow of concatenated frames.
- Skippable frames will be ignored (skipped) by a decompressor. The format of skippable frames is as follows :
+ Skippable frames will be ignored (skipped) by decompressor.
+ The format of skippable frames is as follows :
a) Skippable frame ID - 4 Bytes, Little endian format, any value from 0x184D2A50 to 0x184D2A5F
b) Frame Size - 4 Bytes, Little endian format, unsigned 32-bits
c) Frame Content - any content (User Data) of length equal to Frame Size
- For skippable frames ZSTD_decompressContinue() always returns 0.
- For skippable frames ZSTD_getFrameParams() returns fparamsPtr->windowLog==0 what means that a frame is skippable.
- Note : If fparamsPtr->frameContentSize==0, it is ambiguous: the frame might actually be a Zstd encoded frame with no content.
- For purposes of decompression, it is valid in both cases to skip the frame using
- ZSTD_findFrameCompressedSize to find its size in bytes.
- It also returns Frame Size as fparamsPtr->frameContentSize.
+ For skippable frames ZSTD_getFrameHeader() returns zfhPtr->frameType==ZSTD_skippableFrame.
+ For skippable frames ZSTD_decompressContinue() always returns 0 : it only skips the content.
*/
/*===== Buffer-less streaming decompression functions =====*/
-ZSTDLIB_API size_t ZSTD_getFrameHeader(ZSTD_frameHeader* zfhPtr, const void* src, size_t srcSize); /**< doesn't consume input, see details below */
+typedef enum { ZSTD_frame, ZSTD_skippableFrame } ZSTD_frameType_e;
+typedef struct {
+ unsigned long long frameContentSize; /* if == ZSTD_CONTENTSIZE_UNKNOWN, it means this field is not available. 0 means "empty" */
+ unsigned long long windowSize; /* can be very large, up to <= frameContentSize */
+ unsigned blockSizeMax;
+ ZSTD_frameType_e frameType; /* if == ZSTD_skippableFrame, frameContentSize is the size of skippable content */
+ unsigned headerSize;
+ unsigned dictID;
+ unsigned checksumFlag;
+} ZSTD_frameHeader;
+ZSTDLIB_API size_t ZSTD_getFrameHeader(ZSTD_frameHeader* zfhPtr, const void* src, size_t srcSize); /**< doesn't consume input */
+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 */
+
ZSTDLIB_API size_t ZSTD_decompressBegin(ZSTD_DCtx* dctx);
ZSTDLIB_API size_t ZSTD_decompressBegin_usingDict(ZSTD_DCtx* dctx, const void* dict, size_t dictSize);
-ZSTDLIB_API void ZSTD_copyDCtx(ZSTD_DCtx* dctx, const ZSTD_DCtx* preparedDCtx);
+ZSTDLIB_API size_t ZSTD_decompressBegin_usingDDict(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict);
+
ZSTDLIB_API size_t ZSTD_nextSrcSizeToDecompress(ZSTD_DCtx* dctx);
ZSTDLIB_API size_t ZSTD_decompressContinue(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);
+
+/* misc */
+ZSTDLIB_API void ZSTD_copyDCtx(ZSTD_DCtx* dctx, const ZSTD_DCtx* preparedDCtx);
typedef enum { ZSTDnit_frameHeader, ZSTDnit_blockHeader, ZSTDnit_block, ZSTDnit_lastBlock, ZSTDnit_checksum, ZSTDnit_skippableFrame } ZSTD_nextInputType_e;
ZSTDLIB_API ZSTD_nextInputType_e ZSTD_nextInputType(ZSTD_DCtx* dctx);
+
+
+/*=== New advanced API (experimental, and compression only) ===*/
+
+/* notes on API design :
+ * In this proposal, parameters are pushed one by one into an existing CCtx,
+ * and then applied on all subsequent compression jobs.
+ * When no parameter is ever provided, CCtx is created with compression level ZSTD_CLEVEL_DEFAULT.
+ *
+ * This API is intended to replace all others experimental API.
+ * It can basically do all other use cases, and even new ones.
+ * It stands a good chance to become "stable",
+ * after a reasonable testing period.
+ */
+
+/* note on naming convention :
+ * Initially, the API favored names like ZSTD_setCCtxParameter() .
+ * In this proposal, convention is changed towards ZSTD_CCtx_setParameter() .
+ * The main driver is that it identifies more clearly the target object type.
+ * It feels clearer in light of potential variants :
+ * ZSTD_CDict_setParameter() (rather than ZSTD_setCDictParameter())
+ * ZSTD_DCtx_setParameter() (rather than ZSTD_setDCtxParameter() )
+ * Left variant feels easier to distinguish.
+ */
+
+/* note on enum design :
+ * All enum will be manually set to explicit values before reaching "stable API" status */
+
+typedef enum {
+ /* compression parameters */
+ ZSTD_p_compressionLevel=100, /* Update all compression parameters according to pre-defined cLevel table
+ * Default level is ZSTD_CLEVEL_DEFAULT==3.
+ * Special: value 0 means "do not change cLevel". */
+ ZSTD_p_windowLog, /* Maximum allowed back-reference distance, expressed as power of 2.
+ * Must be clamped between ZSTD_WINDOWLOG_MIN and ZSTD_WINDOWLOG_MAX.
+ * Special: value 0 means "do not change windowLog". */
+ ZSTD_p_hashLog, /* Size of the probe table, as a power of 2.
+ * Resulting table size is (1 << (hashLog+2)).
+ * Must be clamped between ZSTD_HASHLOG_MIN and ZSTD_HASHLOG_MAX.
+ * Larger tables improve compression ratio of strategies <= dFast,
+ * and improve speed of strategies > dFast.
+ * Special: value 0 means "do not change hashLog". */
+ ZSTD_p_chainLog, /* Size of the full-search table, as a power of 2.
+ * Resulting table size is (1 << (chainLog+2)).
+ * Larger tables result in better and slower compression.
+ * This parameter is useless when using "fast" strategy.
+ * Special: value 0 means "do not change chainLog". */
+ ZSTD_p_searchLog, /* Number of search attempts, as a power of 2.
+ * More attempts result in better and slower compression.
+ * This parameter is useless when using "fast" and "dFast" strategies.
+ * Special: value 0 means "do not change searchLog". */
+ ZSTD_p_minMatch, /* Minimum size of searched matches (note : repCode matches can be smaller).
+ * Larger values make faster compression and decompression, but decrease ratio.
+ * Must be clamped between ZSTD_SEARCHLENGTH_MIN and ZSTD_SEARCHLENGTH_MAX.
+ * Note that currently, for all strategies < btopt, effective minimum is 4.
+ * Note that currently, for all strategies > fast, effective maximum is 6.
+ * Special: value 0 means "do not change minMatchLength". */
+ ZSTD_p_targetLength, /* Only useful for strategies >= btopt.
+ * Length of Match considered "good enough" to stop search.
+ * Larger values make compression stronger and slower.
+ * Special: value 0 means "do not change targetLength". */
+ ZSTD_p_compressionStrategy, /* See ZSTD_strategy enum definition.
+ * Cast selected strategy as unsigned for ZSTD_CCtx_setParameter() compatibility.
+ * The higher the value of selected strategy, the more complex it is,
+ * resulting in stronger and slower compression.
+ * Special: value 0 means "do not change strategy". */
+
+ /* frame parameters */
+ ZSTD_p_contentSizeFlag=200, /* Content size is written into frame header _whenever known_ (default:1)
+ * note that content size must be known at the beginning,
+ * it is sent using ZSTD_CCtx_setPledgedSrcSize() */
+ ZSTD_p_checksumFlag, /* A 32-bits checksum of content is written at end of frame (default:0) */
+ ZSTD_p_dictIDFlag, /* When applicable, dictID of dictionary is provided in frame header (default:1) */
+
+ /* multi-threading parameters */
+ ZSTD_p_nbThreads=400, /* Select how many threads a compression job can spawn (default:1)
+ * More threads improve speed, but also increase memory usage.
+ * Can only receive a value > 1 if ZSTD_MULTITHREAD is enabled.
+ * Special: value 0 means "do not change nbThreads" */
+ ZSTD_p_jobSize, /* Size of a compression job. Each compression job is completed in parallel.
+ * 0 means default, which is dynamically determined based on compression parameters.
+ * Job size must be a minimum of overlapSize, or 1 KB, whichever is largest
+ * The minimum size is automatically and transparently enforced */
+ ZSTD_p_overlapSizeLog, /* Size of previous input reloaded at the beginning of each job.
+ * 0 => no overlap, 6(default) => use 1/8th of windowSize, >=9 => use full windowSize */
+
+ /* advanced parameters - may not remain available after API update */
+ ZSTD_p_forceMaxWindow=1100, /* Force back-reference distances to remain < windowSize,
+ * even when referencing into Dictionary content (default:0) */
+ ZSTD_p_enableLongDistanceMatching=1200, /* Enable long distance matching.
+ * This parameter is designed to improve the compression
+ * ratio for large inputs with long distance matches.
+ * This increases the memory usage as well as window size.
+ * Note: setting this parameter sets all the LDM parameters
+ * as well as ZSTD_p_windowLog. It should be set after
+ * ZSTD_p_compressionLevel and before ZSTD_p_windowLog and
+ * other LDM parameters. Setting the compression level
+ * after this parameter overrides the window log, though LDM
+ * will remain enabled until explicitly disabled. */
+ ZSTD_p_ldmHashLog, /* Size of the table for long distance matching, as a power of 2.
+ * Larger values increase memory usage and compression ratio, but decrease
+ * compression speed.
+ * Must be clamped between ZSTD_HASHLOG_MIN and ZSTD_HASHLOG_MAX
+ * (default: 20). */
+ ZSTD_p_ldmMinMatch, /* Minimum size of searched matches for long distance matcher.
+ * Larger/too small values usually decrease compression ratio.
+ * Must be clamped between ZSTD_LDM_MINMATCH_MIN
+ * and ZSTD_LDM_MINMATCH_MAX (default: 64). */
+ ZSTD_p_ldmBucketSizeLog, /* Log size of each bucket in the LDM hash table for collision resolution.
+ * Larger values usually improve collision resolution but may decrease
+ * compression speed.
+ * The maximum value is ZSTD_LDM_BUCKETSIZELOG_MAX (default: 3). */
+ ZSTD_p_ldmHashEveryLog, /* Frequency of inserting/looking up entries in the LDM hash table.
+ * The default is MAX(0, (windowLog - ldmHashLog)) to
+ * optimize hash table usage.
+ * Larger values improve compression speed. Deviating far from the
+ * default value will likely result in a decrease in compression ratio.
+ * Must be clamped between 0 and ZSTD_WINDOWLOG_MAX - ZSTD_HASHLOG_MIN. */
+
+} ZSTD_cParameter;
+
+
+/*! ZSTD_CCtx_setParameter() :
+ * Set one compression parameter, selected by enum ZSTD_cParameter.
+ * 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_CCtx_setParameter(ZSTD_CCtx* cctx, ZSTD_cParameter param, unsigned value);
+
+/*! ZSTD_CCtx_setPledgedSrcSize() :
+ * Total input data size to be compressed as a single frame.
+ * This value will be controlled at the end, and result in error if not respected.
+ * @result : 0, or an error code (which can be tested with ZSTD_isError()).
+ * Note 1 : 0 means zero, empty.
+ * In order to mean "unknown content size", pass constant ZSTD_CONTENTSIZE_UNKNOWN.
+ * Note that ZSTD_CONTENTSIZE_UNKNOWN is default value for new compression jobs.
+ * Note 2 : If all data is provided and consumed in a single round,
+ * this value is overriden by srcSize instead. */
+ZSTDLIB_API size_t ZSTD_CCtx_setPledgedSrcSize(ZSTD_CCtx* cctx, unsigned long long pledgedSrcSize);
+
+/*! ZSTD_CCtx_loadDictionary() :
+ * Create an internal CDict from dict buffer.
+ * Decompression will have to use same buffer.
+ * @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_CCtx_loadDictionary_byReference() to reference dictionary
+ * content instead. The dictionary buffer must then outlive its
+ * users.
+ * Note 2 : Loading a dictionary involves building tables, which are dependent on compression parameters.
+ * For this reason, compression parameters cannot be changed anymore after loading a dictionary.
+ * It's also a CPU-heavy operation, with non-negligible impact on latency.
+ * Note 3 : Dictionary will be used for all future compression jobs.
+ * To return to "no-dictionary" situation, load a NULL dictionary
+ * Note 5 : Use ZSTD_CCtx_loadDictionary_advanced() to select how dictionary
+ * content will be interpreted.
+ */
+ZSTDLIB_API size_t ZSTD_CCtx_loadDictionary(ZSTD_CCtx* cctx, const void* dict, size_t dictSize);
+ZSTDLIB_API size_t ZSTD_CCtx_loadDictionary_byReference(ZSTD_CCtx* cctx, const void* dict, size_t dictSize);
+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);
+
+
+/*! ZSTD_CCtx_refCDict() :
+ * Reference a prepared dictionary, to be used for all next compression jobs.
+ * Note that compression parameters are enforced from within CDict,
+ * and supercede any compression parameter previously set within CCtx.
+ * The dictionary will remain valid for future compression jobs using same CCtx.
+ * @result : 0, or an error code (which can be tested with ZSTD_isError()).
+ * Special : adding a NULL CDict means "return to no-dictionary mode".
+ * Note 1 : Currently, only one dictionary can be managed.
+ * Adding a new dictionary effectively "discards" any previous one.
+ * Note 2 : CDict is just referenced, its lifetime must outlive CCtx.
+ */
+ZSTDLIB_API size_t ZSTD_CCtx_refCDict(ZSTD_CCtx* cctx, const ZSTD_CDict* cdict);
+
+/*! ZSTD_CCtx_refPrefix() :
+ * Reference a prefix (single-usage dictionary) for next compression job.
+ * Decompression need same prefix to properly regenerate data.
+ * Prefix is **only used once**. Tables are discarded at end of compression job.
+ * Subsequent compression jobs will be done without prefix (if none is explicitly referenced).
+ * If there is a need to use same prefix multiple times, consider embedding it into a ZSTD_CDict instead.
+ * @result : 0, or an error code (which can be tested with ZSTD_isError()).
+ * Special : Adding any prefix (including NULL) invalidates any previous prefix or dictionary
+ * Note 1 : Prefix buffer is referenced. It must outlive compression job.
+ * Note 2 : Referencing a prefix involves building tables, which are dependent on compression parameters.
+ * It's a CPU-heavy operation, with non-negligible impact on latency.
+ * Note 3 : By default, the prefix is treated as raw content
+ * (ZSTD_dm_rawContent). Use ZSTD_CCtx_refPrefix_advanced() to alter
+ * dictMode. */
+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);
+
+
+
+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 */
+ ZSTD_e_end /* flush any remaining data and ends current frame. Any future compression starts a new frame. */
+} ZSTD_EndDirective;
+
+/*! ZSTD_compress_generic() :
+ * Behave about the same as ZSTD_compressStream. To note :
+ * - 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
+ * - *dspPos and *srcPos will be updated. They are guaranteed to remain below their respective limit.
+ * - @return provides the minimum amount of data still to flush from internal buffers
+ * 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.
+ * - after a ZSTD_e_end directive, if internal buffer is not fully flushed,
+ * only ZSTD_e_end or ZSTD_e_flush operations are allowed.
+ * It is necessary to fully flush internal buffers
+ * before starting a new compression job, or changing compression parameters.
+ */
+ZSTDLIB_API size_t ZSTD_compress_generic (ZSTD_CCtx* cctx,
+ ZSTD_outBuffer* output,
+ ZSTD_inBuffer* input,
+ ZSTD_EndDirective endOp);
+
+/*! ZSTD_CCtx_reset() :
+ * Return a CCtx to clean state.
+ * Useful after an error, or to interrupt an ongoing compression job and start a new one.
+ * Any internal data not yet flushed is cancelled.
+ * Dictionary (if any) is dropped.
+ * It's possible to modify compression parameters after a reset.
+ */
+ZSTDLIB_API void ZSTD_CCtx_reset(ZSTD_CCtx* cctx); /* Not ready yet ! */
+
+
+/*! ZSTD_compress_generic_simpleArgs() :
+ * Same as ZSTD_compress_generic(),
+ * but using only integral types as arguments.
+ * Argument list is larger and less expressive than ZSTD_{in,out}Buffer,
+ * but can be helpful for binders from dynamic languages
+ * which have troubles handling structures containing memory pointers.
+ */
+size_t ZSTD_compress_generic_simpleArgs (
+ ZSTD_CCtx* cctx,
+ void* dst, size_t dstCapacity, size_t* dstPos,
+ const void* src, size_t srcSize, size_t* srcPos,
+ ZSTD_EndDirective endOp);
+
+
+/** ZSTD_CCtx_params
+ *
+ * - ZSTD_createCCtxParams() : Create a ZSTD_CCtx_params structure
+ * - ZSTD_CCtxParam_setParameter() : Push parameters one by one into an
+ * existing ZSTD_CCtx_params structure. This is similar to
+ * ZSTD_CCtx_setParameter().
+ * - ZSTD_CCtx_setParametersUsingCCtxParams() : Apply parameters to an existing CCtx. These
+ * parameters will be applied to all subsequent compression jobs.
+ * - ZSTD_compress_generic() : Do compression using the CCtx.
+ * - ZSTD_freeCCtxParams() : Free the memory.
+ *
+ * This can be used with ZSTD_estimateCCtxSize_opaque() for static allocation
+ * for single-threaded compression.
+ */
+ZSTDLIB_API ZSTD_CCtx_params* ZSTD_createCCtxParams(void);
+
+/*! ZSTD_resetCCtxParams() :
+ * Reset params to default, with the default compression level.
+ */
+ZSTDLIB_API size_t ZSTD_resetCCtxParams(ZSTD_CCtx_params* params);
+
+/*! 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);
+
/**
Block functions
@@ -773,7 +1216,7 @@ ZSTDLIB_API ZSTD_nextInputType_e ZSTD_nextInputType(ZSTD_DCtx* dctx);
+ 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_getBlockSizeMax() <= ZSTD_BLOCKSIZE_ABSOLUTEMAX
+ - Block size is limited, it must be <= ZSTD_getBlockSize() <= ZSTD_BLOCKSIZE_MAX
+ 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.
@@ -786,12 +1229,13 @@ ZSTDLIB_API ZSTD_nextInputType_e ZSTD_nextInputType(ZSTD_DCtx* dctx);
Use ZSTD_insertBlock() for such a case.
*/
-#define ZSTD_BLOCKSIZE_ABSOLUTEMAX (128 * 1024) /* define, for static allocation */
+#define ZSTD_BLOCKSIZELOG_MAX 17
+#define ZSTD_BLOCKSIZE_MAX (1<<ZSTD_BLOCKSIZELOG_MAX) /* define, for static allocation */
/*===== Raw zstd block functions =====*/
-ZSTDLIB_API size_t ZSTD_getBlockSizeMax(ZSTD_CCtx* cctx);
+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 */