2116 lines
121 KiB
C
2116 lines
121 KiB
C
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/*
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* BSD 3-Clause Clear License
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* 3. Neither the name of the copyright holder nor the names of its
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* contributors may be used to endorse or promote products derived from this
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* software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* Copyright (c) 2016-2020, Yann Collet, Facebook, Inc. All rights reserved.
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*/
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#if defined (__cplusplus)
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extern "C" {
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#endif
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#ifndef ZSTD_H_235446
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#define ZSTD_H_235446
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/* ====== Dependency ======*/
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#include <limits.h> /* INT_MAX */
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#include <stddef.h> /* size_t */
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/* ===== ZSTDLIB_API : control library symbols visibility ===== */
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#ifndef ZSTDLIB_VISIBILITY
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# if defined(__GNUC__) && (__GNUC__ >= 4)
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# define ZSTDLIB_VISIBILITY __attribute__ ((visibility ("default")))
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# else
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# define ZSTDLIB_VISIBILITY
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# endif
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#endif
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#if defined(ZSTD_DLL_EXPORT) && (ZSTD_DLL_EXPORT==1)
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# define ZSTDLIB_API __declspec(dllexport) ZSTDLIB_VISIBILITY
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#elif defined(ZSTD_DLL_IMPORT) && (ZSTD_DLL_IMPORT==1)
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# define ZSTDLIB_API __declspec(dllimport) ZSTDLIB_VISIBILITY /* It isn't required but allows to generate better code, saving a function pointer load from the IAT and an indirect jump.*/
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#else
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# define ZSTDLIB_API ZSTDLIB_VISIBILITY
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#endif
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/*******************************************************************************
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Introduction
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zstd, short for Zstandard, is a fast lossless compression algorithm, targeting
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real-time compression scenarios at zlib-level and better compression ratios.
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The zstd compression library provides in-memory compression and decompression
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functions.
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The library supports regular compression levels from 1 up to ZSTD_maxCLevel(),
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which is currently 22. Levels >= 20, labeled `--ultra`, should be used with
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caution, as they require more memory. The library also offers negative
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compression levels, which extend the range of speed vs. ratio preferences.
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The lower the level, the faster the speed (at the cost of compression).
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Compression can be done in:
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- a single step (described as Simple API)
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- a single step, reusing a context (described as Explicit context)
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- unbounded multiple steps (described as Streaming compression)
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The compression ratio achievable on small data can be highly improved using
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a dictionary. Dictionary compression can be performed in:
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- a single step (described as Simple dictionary API)
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- a single step, reusing a dictionary (described as Bulk-processing
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dictionary API)
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Advanced experimental functions can be accessed using
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`#define ZSTD_STATIC_LINKING_ONLY` before including zstd.h.
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Advanced experimental APIs should never be used with a dynamically-linked
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library. They are not "stable"; their definitions or signatures may change in
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the future. Only static linking is allowed.
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*******************************************************************************/
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/*------ Version ------*/
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#define ZSTD_VERSION_MAJOR 1
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#define ZSTD_VERSION_MINOR 4
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#define ZSTD_VERSION_RELEASE 5
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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); /**< to check runtime library version */
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#define ZSTD_LIB_VERSION ZSTD_VERSION_MAJOR.ZSTD_VERSION_MINOR.ZSTD_VERSION_RELEASE
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#define ZSTD_QUOTE(str) #str
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#define ZSTD_EXPAND_AND_QUOTE(str) ZSTD_QUOTE(str)
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#define ZSTD_VERSION_STRING ZSTD_EXPAND_AND_QUOTE(ZSTD_LIB_VERSION)
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ZSTDLIB_API const char* ZSTD_versionString(void); /* requires v1.3.0+ */
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/* *************************************
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* Default constant
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***************************************/
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#ifndef ZSTD_CLEVEL_DEFAULT
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# define ZSTD_CLEVEL_DEFAULT 3
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#endif
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/* *************************************
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* Constants
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***************************************/
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/* All magic numbers are supposed read/written to/from files/memory using little-endian convention */
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#define ZSTD_MAGICNUMBER 0xFD2FB528 /* valid since v0.8.0 */
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#define ZSTD_MAGIC_DICTIONARY 0xEC30A437 /* valid since v0.7.0 */
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#define ZSTD_MAGIC_SKIPPABLE_START 0x184D2A50 /* all 16 values, from 0x184D2A50 to 0x184D2A5F, signal the beginning of a skippable frame */
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#define ZSTD_MAGIC_SKIPPABLE_MASK 0xFFFFFFF0
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#define ZSTD_BLOCKSIZELOG_MAX 17
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#define ZSTD_BLOCKSIZE_MAX (1<<ZSTD_BLOCKSIZELOG_MAX)
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/***************************************
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* Simple API
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***************************************/
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/*! ZSTD_compress() :
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* Compresses `src` content as a single zstd compressed frame into already allocated `dst`.
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* Hint : compression runs faster if `dstCapacity` >= `ZSTD_compressBound(srcSize)`.
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* @return : compressed size written into `dst` (<= `dstCapacity),
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* or an error code if it fails (which can be tested using ZSTD_isError()). */
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ZSTDLIB_API size_t ZSTD_compress( void* dst, size_t dstCapacity,
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const void* src, size_t srcSize,
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int compressionLevel);
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/*! ZSTD_decompress() :
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* `compressedSize` : must be the _exact_ size of some number of compressed and/or skippable frames.
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* `dstCapacity` is an upper bound of originalSize to regenerate.
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* If user cannot imply a maximum upper bound, it's better to use streaming mode to decompress data.
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* @return : the number of bytes decompressed into `dst` (<= `dstCapacity`),
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* or an errorCode if it fails (which can be tested using ZSTD_isError()). */
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ZSTDLIB_API size_t ZSTD_decompress( void* dst, size_t dstCapacity,
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const void* src, size_t compressedSize);
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/*! ZSTD_getFrameContentSize() : requires v1.3.0+
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* `src` should point to the start of a ZSTD encoded frame.
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* `srcSize` must be at least as large as the frame header.
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* hint : any size >= `ZSTD_frameHeaderSize_max` is large enough.
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* @return : - decompressed size of `src` frame content, if known
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* - ZSTD_CONTENTSIZE_UNKNOWN if the size cannot be determined
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* - ZSTD_CONTENTSIZE_ERROR if an error occurred (e.g. invalid magic number, srcSize too small)
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* note 1 : a 0 return value means the frame is valid but "empty".
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* note 2 : decompressed size is an optional field, it may not be present, typically in streaming mode.
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* When `return==ZSTD_CONTENTSIZE_UNKNOWN`, data to decompress could be any size.
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* In which case, it's necessary to use streaming mode to decompress data.
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* Optionally, application can rely on some implicit limit,
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* as ZSTD_decompress() only needs an upper bound of decompressed size.
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* (For example, data could be necessarily cut into blocks <= 16 KB).
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* note 3 : decompressed size is always present when compression is completed using single-pass functions,
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* such as ZSTD_compress(), ZSTD_compressCCtx() ZSTD_compress_usingDict() or ZSTD_compress_usingCDict().
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* note 4 : decompressed size can be very large (64-bits value),
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* potentially larger than what local system can handle as a single memory segment.
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* In which case, it's necessary to use streaming mode to decompress data.
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* note 5 : If source is untrusted, decompressed size could be wrong or intentionally modified.
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* Always ensure return value fits within application's authorized limits.
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* Each application can set its own limits.
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* note 6 : This function replaces ZSTD_getDecompressedSize() */
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#define ZSTD_CONTENTSIZE_UNKNOWN (0ULL - 1)
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#define ZSTD_CONTENTSIZE_ERROR (0ULL - 2)
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ZSTDLIB_API unsigned long long ZSTD_getFrameContentSize(const void *src, size_t srcSize);
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/*! ZSTD_getDecompressedSize() :
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* NOTE: This function is now obsolete, in favor of ZSTD_getFrameContentSize().
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* Both functions work the same way, but ZSTD_getDecompressedSize() blends
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* "empty", "unknown" and "error" results to the same return value (0),
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* while ZSTD_getFrameContentSize() gives them separate return values.
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* @return : decompressed size of `src` frame content _if known and not empty_, 0 otherwise. */
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ZSTDLIB_API unsigned long long ZSTD_getDecompressedSize(const void* src, size_t srcSize);
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/*! ZSTD_findFrameCompressedSize() :
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* `src` should point to the start of a ZSTD frame or skippable frame.
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* `srcSize` must be >= first frame size
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* @return : the compressed size of the first frame starting at `src`,
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* suitable to pass as `srcSize` to `ZSTD_decompress` or similar,
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* or an error code if input is invalid */
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ZSTDLIB_API size_t ZSTD_findFrameCompressedSize(const void* src, size_t srcSize);
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/*====== Helper functions ======*/
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#define ZSTD_COMPRESSBOUND(srcSize) ((srcSize) + ((srcSize)>>8) + (((srcSize) < (128<<10)) ? (((128<<10) - (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 single-pass 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_minCLevel(void); /*!< minimum negative compression level allowed */
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ZSTDLIB_API int ZSTD_maxCLevel(void); /*!< maximum compression level available */
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/***************************************
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* Explicit context
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***************************************/
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/*= Compression context
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* When compressing many times,
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* it is recommended to allocate a context just once,
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* and re-use it for each successive compression operation.
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* This will make workload friendlier for system's memory.
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* Note : re-using context is just a speed / resource optimization.
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* It doesn't change the compression ratio, which remains identical.
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* Note 2 : In multi-threaded environments,
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* use one different context per thread for parallel execution.
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*/
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typedef struct ZSTD_CCtx_s ZSTD_CCtx;
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ZSTDLIB_API ZSTD_CCtx* ZSTD_createCCtx(void);
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ZSTDLIB_API size_t ZSTD_freeCCtx(ZSTD_CCtx* cctx);
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/*! ZSTD_compressCCtx() :
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* Same as ZSTD_compress(), using an explicit ZSTD_CCtx.
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* Important : in order to behave similarly to `ZSTD_compress()`,
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* this function compresses at requested compression level,
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* __ignoring any other parameter__ .
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* If any advanced parameter was set using the advanced API,
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* they will all be reset. Only `compressionLevel` remains.
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*/
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ZSTDLIB_API size_t ZSTD_compressCCtx(ZSTD_CCtx* cctx,
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void* dst, size_t dstCapacity,
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const void* src, size_t srcSize,
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int compressionLevel);
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/*= Decompression context
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* When decompressing many times,
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* it is recommended to allocate a context only once,
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* and re-use it for each successive compression operation.
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* This will make workload friendlier for system's memory.
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* Use one context per thread for parallel execution. */
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typedef struct ZSTD_DCtx_s ZSTD_DCtx;
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ZSTDLIB_API ZSTD_DCtx* ZSTD_createDCtx(void);
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ZSTDLIB_API size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx);
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/*! ZSTD_decompressDCtx() :
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* Same as ZSTD_decompress(),
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* requires an allocated ZSTD_DCtx.
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* Compatible with sticky parameters.
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*/
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ZSTDLIB_API size_t ZSTD_decompressDCtx(ZSTD_DCtx* dctx,
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void* dst, size_t dstCapacity,
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const void* src, size_t srcSize);
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/***************************************
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* Advanced compression API
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***************************************/
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/* API design :
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* Parameters are pushed one by one into an existing context,
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* using ZSTD_CCtx_set*() functions.
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* Pushed parameters are sticky : they are valid for next compressed frame, and any subsequent frame.
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* "sticky" parameters are applicable to `ZSTD_compress2()` and `ZSTD_compressStream*()` !
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* __They do not apply to "simple" one-shot variants such as ZSTD_compressCCtx()__ .
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*
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* It's possible to reset all parameters to "default" using ZSTD_CCtx_reset().
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*
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* This API supercedes all other "advanced" API entry points in the experimental section.
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* In the future, we expect to remove from experimental API entry points which are redundant with this API.
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*/
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/* Compression strategies, listed from fastest to strongest */
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typedef enum { ZSTD_fast=1,
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ZSTD_dfast=2,
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ZSTD_greedy=3,
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ZSTD_lazy=4,
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ZSTD_lazy2=5,
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ZSTD_btlazy2=6,
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ZSTD_btopt=7,
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ZSTD_btultra=8,
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ZSTD_btultra2=9
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/* note : new strategies _might_ be added in the future.
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Only the order (from fast to strong) is guaranteed */
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} ZSTD_strategy;
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typedef enum {
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/* compression parameters
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* Note: When compressing with a ZSTD_CDict these parameters are superseded
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* by the parameters used to construct the ZSTD_CDict.
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* See ZSTD_CCtx_refCDict() for more info (superseded-by-cdict). */
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ZSTD_c_compressionLevel=100, /* Set compression parameters according to pre-defined cLevel table.
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* Note that exact compression parameters are dynamically determined,
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* depending on both compression level and srcSize (when known).
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* Default level is ZSTD_CLEVEL_DEFAULT==3.
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* Special: value 0 means default, which is controlled by ZSTD_CLEVEL_DEFAULT.
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* Note 1 : it's possible to pass a negative compression level.
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* Note 2 : setting a level does not automatically set all other compression parameters
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* to default. Setting this will however eventually dynamically impact the compression
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* parameters which have not been manually set. The manually set
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* ones will 'stick'. */
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/* Advanced compression parameters :
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* It's possible to pin down compression parameters to some specific values.
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* In which case, these values are no longer dynamically selected by the compressor */
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ZSTD_c_windowLog=101, /* Maximum allowed back-reference distance, expressed as power of 2.
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* This will set a memory budget for streaming decompression,
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* with larger values requiring more memory
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* and typically compressing more.
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||
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* Must be clamped between ZSTD_WINDOWLOG_MIN and ZSTD_WINDOWLOG_MAX.
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* Special: value 0 means "use default windowLog".
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* Note: Using a windowLog greater than ZSTD_WINDOWLOG_LIMIT_DEFAULT
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||
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* requires explicitly allowing such size at streaming decompression stage. */
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||
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ZSTD_c_hashLog=102, /* Size of the initial probe table, as a power of 2.
|
||
|
|
* Resulting memory usage 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 "use default hashLog". */
|
||
|
|
ZSTD_c_chainLog=103, /* Size of the multi-probe search table, as a power of 2.
|
||
|
|
* Resulting memory usage is (1 << (chainLog+2)).
|
||
|
|
* Must be clamped between ZSTD_CHAINLOG_MIN and ZSTD_CHAINLOG_MAX.
|
||
|
|
* Larger tables result in better and slower compression.
|
||
|
|
* This parameter is useless for "fast" strategy.
|
||
|
|
* It's still useful when using "dfast" strategy,
|
||
|
|
* in which case it defines a secondary probe table.
|
||
|
|
* Special: value 0 means "use default chainLog". */
|
||
|
|
ZSTD_c_searchLog=104, /* Number of search attempts, as a power of 2.
|
||
|
|
* More attempts result in better and slower compression.
|
||
|
|
* This parameter is useless for "fast" and "dFast" strategies.
|
||
|
|
* Special: value 0 means "use default searchLog". */
|
||
|
|
ZSTD_c_minMatch=105, /* Minimum size of searched matches.
|
||
|
|
* Note that Zstandard can still find matches of smaller size,
|
||
|
|
* it just tweaks its search algorithm to look for this size and larger.
|
||
|
|
* Larger values increase compression and decompression speed, but decrease ratio.
|
||
|
|
* Must be clamped between ZSTD_MINMATCH_MIN and ZSTD_MINMATCH_MAX.
|
||
|
|
* Note that currently, for all strategies < btopt, effective minimum is 4.
|
||
|
|
* , for all strategies > fast, effective maximum is 6.
|
||
|
|
* Special: value 0 means "use default minMatchLength". */
|
||
|
|
ZSTD_c_targetLength=106, /* Impact of this field depends on strategy.
|
||
|
|
* For strategies btopt, btultra & btultra2:
|
||
|
|
* Length of Match considered "good enough" to stop search.
|
||
|
|
* Larger values make compression stronger, and slower.
|
||
|
|
* For strategy fast:
|
||
|
|
* Distance between match sampling.
|
||
|
|
* Larger values make compression faster, and weaker.
|
||
|
|
* Special: value 0 means "use default targetLength". */
|
||
|
|
ZSTD_c_strategy=107, /* See ZSTD_strategy enum definition.
|
||
|
|
* The higher the value of selected strategy, the more complex it is,
|
||
|
|
* resulting in stronger and slower compression.
|
||
|
|
* Special: value 0 means "use default strategy". */
|
||
|
|
|
||
|
|
/* LDM mode parameters */
|
||
|
|
ZSTD_c_enableLongDistanceMatching=160, /* Enable long distance matching.
|
||
|
|
* This parameter is designed to improve compression ratio
|
||
|
|
* for large inputs, by finding large matches at long distance.
|
||
|
|
* It increases memory usage and window size.
|
||
|
|
* Note: enabling this parameter increases default ZSTD_c_windowLog to 128 MB
|
||
|
|
* except when expressly set to a different value. */
|
||
|
|
ZSTD_c_ldmHashLog=161, /* 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: windowlog - 7.
|
||
|
|
* Special: value 0 means "automatically determine hashlog". */
|
||
|
|
ZSTD_c_ldmMinMatch=162, /* Minimum match size 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.
|
||
|
|
* Special: value 0 means "use default value" (default: 64). */
|
||
|
|
ZSTD_c_ldmBucketSizeLog=163, /* Log size of each bucket in the LDM hash table for collision resolution.
|
||
|
|
* Larger values improve collision resolution but decrease compression speed.
|
||
|
|
* The maximum value is ZSTD_LDM_BUCKETSIZELOG_MAX.
|
||
|
|
* Special: value 0 means "use default value" (default: 3). */
|
||
|
|
ZSTD_c_ldmHashRateLog=164, /* Frequency of inserting/looking up entries into the LDM hash table.
|
||
|
|
* Must be clamped between 0 and (ZSTD_WINDOWLOG_MAX - ZSTD_HASHLOG_MIN).
|
||
|
|
* Default is MAX(0, (windowLog - ldmHashLog)), optimizing hash table usage.
|
||
|
|
* Larger values improve compression speed.
|
||
|
|
* Deviating far from default value will likely result in a compression ratio decrease.
|
||
|
|
* Special: value 0 means "automatically determine hashRateLog". */
|
||
|
|
|
||
|
|
/* frame parameters */
|
||
|
|
ZSTD_c_contentSizeFlag=200, /* Content size will be written into frame header _whenever known_ (default:1)
|
||
|
|
* Content size must be known at the beginning of compression.
|
||
|
|
* This is automatically the case when using ZSTD_compress2(),
|
||
|
|
* For streaming scenarios, content size must be provided with ZSTD_CCtx_setPledgedSrcSize() */
|
||
|
|
ZSTD_c_checksumFlag=201, /* A 32-bits checksum of content is written at end of frame (default:0) */
|
||
|
|
ZSTD_c_dictIDFlag=202, /* When applicable, dictionary's ID is written into frame header (default:1) */
|
||
|
|
|
||
|
|
/* multi-threading parameters */
|
||
|
|
/* These parameters are only useful if multi-threading is enabled (compiled with build macro ZSTD_MULTITHREAD).
|
||
|
|
* They return an error otherwise. */
|
||
|
|
ZSTD_c_nbWorkers=400, /* Select how many threads will be spawned to compress in parallel.
|
||
|
|
* When nbWorkers >= 1, triggers asynchronous mode when used with ZSTD_compressStream*() :
|
||
|
|
* ZSTD_compressStream*() consumes input and flush output if possible, but immediately gives back control to caller,
|
||
|
|
* while compression work is performed in parallel, within worker threads.
|
||
|
|
* (note : a strong exception to this rule is when first invocation of ZSTD_compressStream2() sets ZSTD_e_end :
|
||
|
|
* in which case, ZSTD_compressStream2() delegates to ZSTD_compress2(), which is always a blocking call).
|
||
|
|
* More workers improve speed, but also increase memory usage.
|
||
|
|
* Default value is `0`, aka "single-threaded mode" : no worker is spawned, compression is performed inside Caller's thread, all invocations are blocking */
|
||
|
|
ZSTD_c_jobSize=401, /* Size of a compression job. This value is enforced only when nbWorkers >= 1.
|
||
|
|
* Each compression job is completed in parallel, so this value can indirectly impact the nb of active threads.
|
||
|
|
* 0 means default, which is dynamically determined based on compression parameters.
|
||
|
|
* Job size must be a minimum of overlap size, or 1 MB, whichever is largest.
|
||
|
|
* The minimum size is automatically and transparently enforced. */
|
||
|
|
ZSTD_c_overlapLog=402, /* Control the overlap size, as a fraction of window size.
|
||
|
|
* The overlap size is an amount of data reloaded from previous job at the beginning of a new job.
|
||
|
|
* It helps preserve compression ratio, while each job is compressed in parallel.
|
||
|
|
* This value is enforced only when nbWorkers >= 1.
|
||
|
|
* Larger values increase compression ratio, but decrease speed.
|
||
|
|
* Possible values range from 0 to 9 :
|
||
|
|
* - 0 means "default" : value will be determined by the library, depending on strategy
|
||
|
|
* - 1 means "no overlap"
|
||
|
|
* - 9 means "full overlap", using a full window size.
|
||
|
|
* Each intermediate rank increases/decreases load size by a factor 2 :
|
||
|
|
* 9: full window; 8: w/2; 7: w/4; 6: w/8; 5:w/16; 4: w/32; 3:w/64; 2:w/128; 1:no overlap; 0:default
|
||
|
|
* default value varies between 6 and 9, depending on strategy */
|
||
|
|
|
||
|
|
/* note : additional experimental parameters are also available
|
||
|
|
* within the experimental section of the API.
|
||
|
|
* At the time of this writing, they include :
|
||
|
|
* ZSTD_c_rsyncable
|
||
|
|
* ZSTD_c_format
|
||
|
|
* ZSTD_c_forceMaxWindow
|
||
|
|
* ZSTD_c_forceAttachDict
|
||
|
|
* ZSTD_c_literalCompressionMode
|
||
|
|
* ZSTD_c_targetCBlockSize
|
||
|
|
* ZSTD_c_srcSizeHint
|
||
|
|
* Because they are not stable, it's necessary to define ZSTD_STATIC_LINKING_ONLY to access them.
|
||
|
|
* note : never ever use experimentalParam? names directly;
|
||
|
|
* also, the enums values themselves are unstable and can still change.
|
||
|
|
*/
|
||
|
|
ZSTD_c_experimentalParam1=500,
|
||
|
|
ZSTD_c_experimentalParam2=10,
|
||
|
|
ZSTD_c_experimentalParam3=1000,
|
||
|
|
ZSTD_c_experimentalParam4=1001,
|
||
|
|
ZSTD_c_experimentalParam5=1002,
|
||
|
|
ZSTD_c_experimentalParam6=1003,
|
||
|
|
ZSTD_c_experimentalParam7=1004
|
||
|
|
} ZSTD_cParameter;
|
||
|
|
|
||
|
|
typedef struct {
|
||
|
|
size_t error;
|
||
|
|
int lowerBound;
|
||
|
|
int upperBound;
|
||
|
|
} ZSTD_bounds;
|
||
|
|
|
||
|
|
/*! ZSTD_cParam_getBounds() :
|
||
|
|
* All parameters must belong to an interval with lower and upper bounds,
|
||
|
|
* otherwise they will either trigger an error or be automatically clamped.
|
||
|
|
* @return : a structure, ZSTD_bounds, which contains
|
||
|
|
* - an error status field, which must be tested using ZSTD_isError()
|
||
|
|
* - lower and upper bounds, both inclusive
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API ZSTD_bounds ZSTD_cParam_getBounds(ZSTD_cParameter cParam);
|
||
|
|
|
||
|
|
/*! ZSTD_CCtx_setParameter() :
|
||
|
|
* Set one compression parameter, selected by enum ZSTD_cParameter.
|
||
|
|
* All parameters have valid bounds. Bounds can be queried using ZSTD_cParam_getBounds().
|
||
|
|
* Providing a value beyond bound will either clamp it, or trigger an error (depending on parameter).
|
||
|
|
* Setting a parameter is generally only possible during frame initialization (before starting compression).
|
||
|
|
* Exception : when using multi-threading mode (nbWorkers >= 1),
|
||
|
|
* the following parameters can be updated _during_ compression (within same frame):
|
||
|
|
* => compressionLevel, hashLog, chainLog, searchLog, minMatch, targetLength and strategy.
|
||
|
|
* new parameters will be active for next job only (after a flush()).
|
||
|
|
* @return : an error code (which can be tested using ZSTD_isError()).
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API size_t ZSTD_CCtx_setParameter(ZSTD_CCtx* cctx, ZSTD_cParameter param, int value);
|
||
|
|
|
||
|
|
/*! ZSTD_CCtx_setPledgedSrcSize() :
|
||
|
|
* Total input data size to be compressed as a single frame.
|
||
|
|
* Value will be written in frame header, unless if explicitly forbidden using ZSTD_c_contentSizeFlag.
|
||
|
|
* This value will also be controlled at end of frame, and trigger an error if not respected.
|
||
|
|
* @result : 0, or an error code (which can be tested with ZSTD_isError()).
|
||
|
|
* Note 1 : pledgedSrcSize==0 actually means zero, aka an empty frame.
|
||
|
|
* In order to mean "unknown content size", pass constant ZSTD_CONTENTSIZE_UNKNOWN.
|
||
|
|
* ZSTD_CONTENTSIZE_UNKNOWN is default value for any new frame.
|
||
|
|
* Note 2 : pledgedSrcSize is only valid once, for the next frame.
|
||
|
|
* It's discarded at the end of the frame, and replaced by ZSTD_CONTENTSIZE_UNKNOWN.
|
||
|
|
* Note 3 : Whenever all input data is provided and consumed in a single round,
|
||
|
|
* for example with ZSTD_compress2(),
|
||
|
|
* or invoking immediately ZSTD_compressStream2(,,,ZSTD_e_end),
|
||
|
|
* this value is automatically overridden by srcSize instead.
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API size_t ZSTD_CCtx_setPledgedSrcSize(ZSTD_CCtx* cctx, unsigned long long pledgedSrcSize);
|
||
|
|
|
||
|
|
typedef enum {
|
||
|
|
ZSTD_reset_session_only = 1,
|
||
|
|
ZSTD_reset_parameters = 2,
|
||
|
|
ZSTD_reset_session_and_parameters = 3
|
||
|
|
} ZSTD_ResetDirective;
|
||
|
|
|
||
|
|
/*! ZSTD_CCtx_reset() :
|
||
|
|
* There are 2 different things that can be reset, independently or jointly :
|
||
|
|
* - The session : will stop compressing current frame, and make CCtx ready to start a new one.
|
||
|
|
* Useful after an error, or to interrupt any ongoing compression.
|
||
|
|
* Any internal data not yet flushed is cancelled.
|
||
|
|
* Compression parameters and dictionary remain unchanged.
|
||
|
|
* They will be used to compress next frame.
|
||
|
|
* Resetting session never fails.
|
||
|
|
* - The parameters : changes all parameters back to "default".
|
||
|
|
* This removes any reference to any dictionary too.
|
||
|
|
* Parameters can only be changed between 2 sessions (i.e. no compression is currently ongoing)
|
||
|
|
* otherwise the reset fails, and function returns an error value (which can be tested using ZSTD_isError())
|
||
|
|
* - Both : similar to resetting the session, followed by resetting parameters.
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API size_t ZSTD_CCtx_reset(ZSTD_CCtx* cctx, ZSTD_ResetDirective reset);
|
||
|
|
|
||
|
|
/*! ZSTD_compress2() :
|
||
|
|
* Behave the same as ZSTD_compressCCtx(), but compression parameters are set using the advanced API.
|
||
|
|
* ZSTD_compress2() always starts a new frame.
|
||
|
|
* Should cctx hold data from a previously unfinished frame, everything about it is forgotten.
|
||
|
|
* - Compression parameters are pushed into CCtx before starting compression, using ZSTD_CCtx_set*()
|
||
|
|
* - The function is always blocking, returns when compression is completed.
|
||
|
|
* Hint : compression runs faster if `dstCapacity` >= `ZSTD_compressBound(srcSize)`.
|
||
|
|
* @return : compressed size written into `dst` (<= `dstCapacity),
|
||
|
|
* or an error code if it fails (which can be tested using ZSTD_isError()).
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API size_t ZSTD_compress2( ZSTD_CCtx* cctx,
|
||
|
|
void* dst, size_t dstCapacity,
|
||
|
|
const void* src, size_t srcSize);
|
||
|
|
|
||
|
|
|
||
|
|
/***************************************
|
||
|
|
* Advanced decompression API
|
||
|
|
***************************************/
|
||
|
|
|
||
|
|
/* The advanced API pushes parameters one by one into an existing DCtx context.
|
||
|
|
* Parameters are sticky, and remain valid for all following frames
|
||
|
|
* using the same DCtx context.
|
||
|
|
* It's possible to reset parameters to default values using ZSTD_DCtx_reset().
|
||
|
|
* Note : This API is compatible with existing ZSTD_decompressDCtx() and ZSTD_decompressStream().
|
||
|
|
* Therefore, no new decompression function is necessary.
|
||
|
|
*/
|
||
|
|
|
||
|
|
typedef enum {
|
||
|
|
|
||
|
|
ZSTD_d_windowLogMax=100, /* Select a size limit (in power of 2) beyond which
|
||
|
|
* the streaming API will refuse to allocate memory buffer
|
||
|
|
* in order to protect the host from unreasonable memory requirements.
|
||
|
|
* This parameter is only useful in streaming mode, since no internal buffer is allocated in single-pass mode.
|
||
|
|
* By default, a decompression context accepts window sizes <= (1 << ZSTD_WINDOWLOG_LIMIT_DEFAULT).
|
||
|
|
* Special: value 0 means "use default maximum windowLog". */
|
||
|
|
|
||
|
|
/* note : additional experimental parameters are also available
|
||
|
|
* within the experimental section of the API.
|
||
|
|
* At the time of this writing, they include :
|
||
|
|
* ZSTD_d_format
|
||
|
|
* ZSTD_d_stableOutBuffer
|
||
|
|
* Because they are not stable, it's necessary to define ZSTD_STATIC_LINKING_ONLY to access them.
|
||
|
|
* note : never ever use experimentalParam? names directly
|
||
|
|
*/
|
||
|
|
ZSTD_d_experimentalParam1=1000,
|
||
|
|
ZSTD_d_experimentalParam2=1001
|
||
|
|
|
||
|
|
} ZSTD_dParameter;
|
||
|
|
|
||
|
|
/*! ZSTD_dParam_getBounds() :
|
||
|
|
* All parameters must belong to an interval with lower and upper bounds,
|
||
|
|
* otherwise they will either trigger an error or be automatically clamped.
|
||
|
|
* @return : a structure, ZSTD_bounds, which contains
|
||
|
|
* - an error status field, which must be tested using ZSTD_isError()
|
||
|
|
* - both lower and upper bounds, inclusive
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API ZSTD_bounds ZSTD_dParam_getBounds(ZSTD_dParameter dParam);
|
||
|
|
|
||
|
|
/*! ZSTD_DCtx_setParameter() :
|
||
|
|
* Set one compression parameter, selected by enum ZSTD_dParameter.
|
||
|
|
* All parameters have valid bounds. Bounds can be queried using ZSTD_dParam_getBounds().
|
||
|
|
* Providing a value beyond bound will either clamp it, or trigger an error (depending on parameter).
|
||
|
|
* Setting a parameter is only possible during frame initialization (before starting decompression).
|
||
|
|
* @return : 0, or an error code (which can be tested using ZSTD_isError()).
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API size_t ZSTD_DCtx_setParameter(ZSTD_DCtx* dctx, ZSTD_dParameter param, int value);
|
||
|
|
|
||
|
|
/*! ZSTD_DCtx_reset() :
|
||
|
|
* Return a DCtx to clean state.
|
||
|
|
* Session and parameters can be reset jointly or separately.
|
||
|
|
* Parameters can only be reset when no active frame is being decompressed.
|
||
|
|
* @return : 0, or an error code, which can be tested with ZSTD_isError()
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API size_t ZSTD_DCtx_reset(ZSTD_DCtx* dctx, ZSTD_ResetDirective reset);
|
||
|
|
|
||
|
|
|
||
|
|
/****************************
|
||
|
|
* Streaming
|
||
|
|
****************************/
|
||
|
|
|
||
|
|
typedef struct ZSTD_inBuffer_s {
|
||
|
|
const void* src; /**< start of input buffer */
|
||
|
|
size_t size; /**< size of input buffer */
|
||
|
|
size_t pos; /**< position where reading stopped. Will be updated. Necessarily 0 <= pos <= size */
|
||
|
|
} ZSTD_inBuffer;
|
||
|
|
|
||
|
|
typedef struct ZSTD_outBuffer_s {
|
||
|
|
void* dst; /**< start of output buffer */
|
||
|
|
size_t size; /**< size of output buffer */
|
||
|
|
size_t pos; /**< position where writing stopped. Will be updated. Necessarily 0 <= pos <= size */
|
||
|
|
} ZSTD_outBuffer;
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
/*-***********************************************************************
|
||
|
|
* Streaming compression - HowTo
|
||
|
|
*
|
||
|
|
* A ZSTD_CStream object is required to track streaming operation.
|
||
|
|
* Use ZSTD_createCStream() and ZSTD_freeCStream() to create/release resources.
|
||
|
|
* ZSTD_CStream objects can be reused multiple times on consecutive compression operations.
|
||
|
|
* It is recommended to re-use ZSTD_CStream since it will play nicer with system's memory, by re-using already allocated memory.
|
||
|
|
*
|
||
|
|
* For parallel execution, use one separate ZSTD_CStream per thread.
|
||
|
|
*
|
||
|
|
* note : since v1.3.0, ZSTD_CStream and ZSTD_CCtx are the same thing.
|
||
|
|
*
|
||
|
|
* Parameters are sticky : when starting a new compression on the same context,
|
||
|
|
* it will re-use the same sticky parameters as previous compression session.
|
||
|
|
* When in doubt, it's recommended to fully initialize the context before usage.
|
||
|
|
* Use ZSTD_CCtx_reset() to reset the context and ZSTD_CCtx_setParameter(),
|
||
|
|
* ZSTD_CCtx_setPledgedSrcSize(), or ZSTD_CCtx_loadDictionary() and friends to
|
||
|
|
* set more specific parameters, the pledged source size, or load a dictionary.
|
||
|
|
*
|
||
|
|
* Use ZSTD_compressStream2() with ZSTD_e_continue as many times as necessary to
|
||
|
|
* consume input stream. The function will automatically update both `pos`
|
||
|
|
* fields within `input` and `output`.
|
||
|
|
* Note that the function may not consume the entire input, for example, because
|
||
|
|
* the output buffer is already full, in which case `input.pos < input.size`.
|
||
|
|
* The caller must check if input has been entirely consumed.
|
||
|
|
* If not, the caller must make some room to receive more compressed data,
|
||
|
|
* and then present again remaining input data.
|
||
|
|
* note: ZSTD_e_continue is guaranteed to make some forward progress when called,
|
||
|
|
* but doesn't guarantee maximal forward progress. This is especially relevant
|
||
|
|
* when compressing with multiple threads. The call won't block if it can
|
||
|
|
* consume some input, but if it can't it will wait for some, but not all,
|
||
|
|
* output to be flushed.
|
||
|
|
* @return : provides a minimum amount of data remaining to be flushed from internal buffers
|
||
|
|
* or an error code, which can be tested using ZSTD_isError().
|
||
|
|
*
|
||
|
|
* At any moment, it's possible to flush whatever data might remain stuck within internal buffer,
|
||
|
|
* using ZSTD_compressStream2() with ZSTD_e_flush. `output->pos` will be updated.
|
||
|
|
* Note that, if `output->size` is too small, a single invocation with ZSTD_e_flush might not be enough (return code > 0).
|
||
|
|
* In which case, make some room to receive more compressed data, and call again ZSTD_compressStream2() with ZSTD_e_flush.
|
||
|
|
* You must continue calling ZSTD_compressStream2() with ZSTD_e_flush until it returns 0, at which point you can change the
|
||
|
|
* operation.
|
||
|
|
* note: ZSTD_e_flush will flush as much output as possible, meaning when compressing with multiple threads, it will
|
||
|
|
* block until the flush is complete or the output buffer is full.
|
||
|
|
* @return : 0 if internal buffers are entirely flushed,
|
||
|
|
* >0 if some data still present within internal buffer (the value is minimal estimation of remaining size),
|
||
|
|
* or an error code, which can be tested using ZSTD_isError().
|
||
|
|
*
|
||
|
|
* Calling ZSTD_compressStream2() with ZSTD_e_end 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.
|
||
|
|
* flush operation is the same, and follows same rules as calling ZSTD_compressStream2() with ZSTD_e_flush.
|
||
|
|
* You must continue calling ZSTD_compressStream2() with ZSTD_e_end until it returns 0, at which point you are free to
|
||
|
|
* start a new frame.
|
||
|
|
* note: ZSTD_e_end will flush as much output as possible, meaning when compressing with multiple threads, it will
|
||
|
|
* block until the flush is complete or the output buffer is full.
|
||
|
|
* @return : 0 if frame fully completed and fully flushed,
|
||
|
|
* >0 if some data still present within internal buffer (the value is minimal estimation of remaining size),
|
||
|
|
* or an error code, which can be tested using ZSTD_isError().
|
||
|
|
*
|
||
|
|
* *******************************************************************/
|
||
|
|
|
||
|
|
typedef ZSTD_CCtx ZSTD_CStream; /**< CCtx and CStream are now effectively same object (>= v1.3.0) */
|
||
|
|
/* Continue to distinguish them for compatibility with older versions <= v1.2.0 */
|
||
|
|
/*===== ZSTD_CStream management functions =====*/
|
||
|
|
ZSTDLIB_API ZSTD_CStream* ZSTD_createCStream(void);
|
||
|
|
ZSTDLIB_API size_t ZSTD_freeCStream(ZSTD_CStream* zcs);
|
||
|
|
|
||
|
|
/*===== Streaming compression functions =====*/
|
||
|
|
typedef enum {
|
||
|
|
ZSTD_e_continue=0, /* collect more data, encoder decides when to output compressed result, for optimal compression ratio */
|
||
|
|
ZSTD_e_flush=1, /* flush any data provided so far,
|
||
|
|
* it creates (at least) one new block, that can be decoded immediately on reception;
|
||
|
|
* frame will continue: any future data can still reference previously compressed data, improving compression.
|
||
|
|
* note : multithreaded compression will block to flush as much output as possible. */
|
||
|
|
ZSTD_e_end=2 /* flush any remaining data _and_ close current frame.
|
||
|
|
* note that frame is only closed after compressed data is fully flushed (return value == 0).
|
||
|
|
* After that point, any additional data starts a new frame.
|
||
|
|
* note : each frame is independent (does not reference any content from previous frame).
|
||
|
|
: note : multithreaded compression will block to flush as much output as possible. */
|
||
|
|
} ZSTD_EndDirective;
|
||
|
|
|
||
|
|
/*! ZSTD_compressStream2() :
|
||
|
|
* Behaves about the same as ZSTD_compressStream, with additional control on end directive.
|
||
|
|
* - Compression parameters are pushed into CCtx before starting compression, using ZSTD_CCtx_set*()
|
||
|
|
* - Compression parameters cannot be changed once compression is started (save a list of exceptions in multi-threading mode)
|
||
|
|
* - output->pos must be <= dstCapacity, input->pos must be <= srcSize
|
||
|
|
* - output->pos and input->pos will be updated. They are guaranteed to remain below their respective limit.
|
||
|
|
* - When nbWorkers==0 (default), function is blocking : it completes its job before returning to caller.
|
||
|
|
* - When nbWorkers>=1, function is non-blocking : it just acquires a copy of input, and distributes jobs to internal worker threads, flush whatever is available,
|
||
|
|
* and then immediately returns, just indicating that there is some data remaining to be flushed.
|
||
|
|
* The function nonetheless guarantees forward progress : it will return only after it reads or write at least 1+ byte.
|
||
|
|
* - Exception : if the first call requests a ZSTD_e_end directive and provides enough dstCapacity, the function delegates to ZSTD_compress2() which is always blocking.
|
||
|
|
* - @return provides a minimum amount of data remaining to be flushed from internal buffers
|
||
|
|
* or an error code, which can be tested using ZSTD_isError().
|
||
|
|
* if @return != 0, flush is not fully completed, there is still some data left within internal buffers.
|
||
|
|
* This is useful for ZSTD_e_flush, since in this case more flushes are necessary to empty all buffers.
|
||
|
|
* For ZSTD_e_end, @return == 0 when internal buffers are fully flushed and frame is completed.
|
||
|
|
* - after a ZSTD_e_end directive, if internal buffer is not fully flushed (@return != 0),
|
||
|
|
* only ZSTD_e_end or ZSTD_e_flush operations are allowed.
|
||
|
|
* Before starting a new compression job, or changing compression parameters,
|
||
|
|
* it is required to fully flush internal buffers.
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API size_t ZSTD_compressStream2( ZSTD_CCtx* cctx,
|
||
|
|
ZSTD_outBuffer* output,
|
||
|
|
ZSTD_inBuffer* input,
|
||
|
|
ZSTD_EndDirective endOp);
|
||
|
|
|
||
|
|
|
||
|
|
/* These buffer sizes are softly recommended.
|
||
|
|
* They are not required : ZSTD_compressStream*() happily accepts any buffer size, for both input and output.
|
||
|
|
* Respecting the recommended size just makes it a bit easier for ZSTD_compressStream*(),
|
||
|
|
* reducing the amount of memory shuffling and buffering, resulting in minor performance savings.
|
||
|
|
*
|
||
|
|
* However, note that these recommendations are from the perspective of a C caller program.
|
||
|
|
* If the streaming interface is invoked from some other language,
|
||
|
|
* especially managed ones such as Java or Go, through a foreign function interface such as jni or cgo,
|
||
|
|
* a major performance rule is to reduce crossing such interface to an absolute minimum.
|
||
|
|
* It's not rare that performance ends being spent more into the interface, rather than compression itself.
|
||
|
|
* In which cases, prefer using large buffers, as large as practical,
|
||
|
|
* for both input and output, to reduce the nb of roundtrips.
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API size_t ZSTD_CStreamInSize(void); /**< recommended size for input buffer */
|
||
|
|
ZSTDLIB_API size_t ZSTD_CStreamOutSize(void); /**< recommended size for output buffer. Guarantee to successfully flush at least one complete compressed block. */
|
||
|
|
|
||
|
|
|
||
|
|
/* *****************************************************************************
|
||
|
|
* This following is a legacy streaming API.
|
||
|
|
* It can be replaced by ZSTD_CCtx_reset() and ZSTD_compressStream2().
|
||
|
|
* It is redundant, but remains fully supported.
|
||
|
|
* Advanced parameters and dictionary compression can only be used through the
|
||
|
|
* new API.
|
||
|
|
******************************************************************************/
|
||
|
|
|
||
|
|
/*!
|
||
|
|
* Equivalent to:
|
||
|
|
*
|
||
|
|
* ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only);
|
||
|
|
* ZSTD_CCtx_refCDict(zcs, NULL); // clear the dictionary (if any)
|
||
|
|
* ZSTD_CCtx_setParameter(zcs, ZSTD_c_compressionLevel, compressionLevel);
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API size_t ZSTD_initCStream(ZSTD_CStream* zcs, int compressionLevel);
|
||
|
|
/*!
|
||
|
|
* Alternative for ZSTD_compressStream2(zcs, output, input, ZSTD_e_continue).
|
||
|
|
* NOTE: The return value is different. ZSTD_compressStream() returns a hint for
|
||
|
|
* the next read size (if non-zero and not an error). ZSTD_compressStream2()
|
||
|
|
* returns the minimum nb of bytes left to flush (if non-zero and not an error).
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API size_t ZSTD_compressStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output, ZSTD_inBuffer* input);
|
||
|
|
/*! Equivalent to ZSTD_compressStream2(zcs, output, &emptyInput, ZSTD_e_flush). */
|
||
|
|
ZSTDLIB_API size_t ZSTD_flushStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output);
|
||
|
|
/*! Equivalent to ZSTD_compressStream2(zcs, output, &emptyInput, ZSTD_e_end). */
|
||
|
|
ZSTDLIB_API size_t ZSTD_endStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output);
|
||
|
|
|
||
|
|
|
||
|
|
/*-***************************************************************************
|
||
|
|
* Streaming decompression - HowTo
|
||
|
|
*
|
||
|
|
* A ZSTD_DStream object is required to track streaming operations.
|
||
|
|
* Use ZSTD_createDStream() and ZSTD_freeDStream() to create/release resources.
|
||
|
|
* ZSTD_DStream objects can be re-used multiple times.
|
||
|
|
*
|
||
|
|
* Use ZSTD_initDStream() to start a new decompression operation.
|
||
|
|
* @return : recommended first input size
|
||
|
|
* Alternatively, use advanced API to set specific properties.
|
||
|
|
*
|
||
|
|
* Use ZSTD_decompressStream() repetitively to consume your input.
|
||
|
|
* The function will update both `pos` fields.
|
||
|
|
* If `input.pos < input.size`, some input has not been consumed.
|
||
|
|
* It's up to the caller to present again remaining data.
|
||
|
|
* The function tries to flush all data decoded immediately, respecting output buffer size.
|
||
|
|
* If `output.pos < output.size`, decoder has flushed everything it could.
|
||
|
|
* But if `output.pos == output.size`, there might be some data left within internal buffers.,
|
||
|
|
* In which case, call ZSTD_decompressStream() again to flush whatever remains in the buffer.
|
||
|
|
* Note : with no additional input provided, amount of data flushed is necessarily <= ZSTD_BLOCKSIZE_MAX.
|
||
|
|
* @return : 0 when a frame is completely decoded and fully flushed,
|
||
|
|
* or an error code, which can be tested using ZSTD_isError(),
|
||
|
|
* or any other value > 0, which means there is still some decoding or flushing to do to complete current frame :
|
||
|
|
* the return value is a suggested next input size (just a hint for better latency)
|
||
|
|
* that will never request more than the remaining frame size.
|
||
|
|
* *******************************************************************************/
|
||
|
|
|
||
|
|
typedef ZSTD_DCtx ZSTD_DStream; /**< DCtx and DStream are now effectively same object (>= v1.3.0) */
|
||
|
|
/* For compatibility with versions <= v1.2.0, prefer differentiating them. */
|
||
|
|
/*===== ZSTD_DStream management functions =====*/
|
||
|
|
ZSTDLIB_API ZSTD_DStream* ZSTD_createDStream(void);
|
||
|
|
ZSTDLIB_API size_t ZSTD_freeDStream(ZSTD_DStream* zds);
|
||
|
|
|
||
|
|
/*===== Streaming decompression functions =====*/
|
||
|
|
|
||
|
|
/* This function is redundant with the advanced API and equivalent to:
|
||
|
|
*
|
||
|
|
* ZSTD_DCtx_reset(zds, ZSTD_reset_session_only);
|
||
|
|
* ZSTD_DCtx_refDDict(zds, NULL);
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API size_t ZSTD_initDStream(ZSTD_DStream* zds);
|
||
|
|
|
||
|
|
ZSTDLIB_API size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inBuffer* input);
|
||
|
|
|
||
|
|
ZSTDLIB_API size_t ZSTD_DStreamInSize(void); /*!< recommended size for input buffer */
|
||
|
|
ZSTDLIB_API size_t ZSTD_DStreamOutSize(void); /*!< recommended size for output buffer. Guarantee to successfully flush at least one complete block in all circumstances. */
|
||
|
|
|
||
|
|
|
||
|
|
/**************************
|
||
|
|
* Simple dictionary API
|
||
|
|
***************************/
|
||
|
|
/*! ZSTD_compress_usingDict() :
|
||
|
|
* Compression at an explicit compression level using a Dictionary.
|
||
|
|
* A dictionary can be any arbitrary data segment (also called a prefix),
|
||
|
|
* or a buffer with specified information (see dictBuilder/zdict.h).
|
||
|
|
* Note : This function loads the dictionary, resulting in significant startup delay.
|
||
|
|
* It's intended for a dictionary used only once.
|
||
|
|
* Note 2 : 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,
|
||
|
|
const void* dict,size_t dictSize,
|
||
|
|
int compressionLevel);
|
||
|
|
|
||
|
|
/*! ZSTD_decompress_usingDict() :
|
||
|
|
* Decompression using a known Dictionary.
|
||
|
|
* Dictionary must be identical to the one used during compression.
|
||
|
|
* Note : This function loads the dictionary, resulting in significant startup delay.
|
||
|
|
* It's intended for a dictionary used only once.
|
||
|
|
* 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);
|
||
|
|
|
||
|
|
|
||
|
|
/***********************************
|
||
|
|
* Bulk processing dictionary API
|
||
|
|
**********************************/
|
||
|
|
typedef struct ZSTD_CDict_s ZSTD_CDict;
|
||
|
|
|
||
|
|
/*! ZSTD_createCDict() :
|
||
|
|
* When compressing multiple messages or blocks using the same dictionary,
|
||
|
|
* it's recommended to digest the dictionary only once, since it's a costly operation.
|
||
|
|
* ZSTD_createCDict() will create a state from digesting a dictionary.
|
||
|
|
* The resulting state can be used for future compression operations with very limited startup cost.
|
||
|
|
* 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, because its content is copied within CDict.
|
||
|
|
* Note 1 : Consider experimental function `ZSTD_createCDict_byReference()` if you prefer to not duplicate @dictBuffer content.
|
||
|
|
* Note 2 : A ZSTD_CDict can be created from an empty @dictBuffer,
|
||
|
|
* in which case the only thing that it transports is the @compressionLevel.
|
||
|
|
* This can be useful in a pipeline featuring ZSTD_compress_usingCDict() exclusively,
|
||
|
|
* expecting a ZSTD_CDict parameter with any data, including those without a known dictionary. */
|
||
|
|
ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict(const void* dictBuffer, size_t dictSize,
|
||
|
|
int compressionLevel);
|
||
|
|
|
||
|
|
/*! ZSTD_freeCDict() :
|
||
|
|
* Function frees memory allocated by ZSTD_createCDict(). */
|
||
|
|
ZSTDLIB_API size_t ZSTD_freeCDict(ZSTD_CDict* CDict);
|
||
|
|
|
||
|
|
/*! ZSTD_compress_usingCDict() :
|
||
|
|
* Compression using a digested Dictionary.
|
||
|
|
* Recommended when same dictionary is used multiple times.
|
||
|
|
* Note : compression level is _decided at dictionary creation time_,
|
||
|
|
* and frame parameters are hardcoded (dictID=yes, contentSize=yes, checksum=no) */
|
||
|
|
ZSTDLIB_API size_t ZSTD_compress_usingCDict(ZSTD_CCtx* cctx,
|
||
|
|
void* dst, size_t dstCapacity,
|
||
|
|
const void* src, size_t srcSize,
|
||
|
|
const ZSTD_CDict* cdict);
|
||
|
|
|
||
|
|
|
||
|
|
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. */
|
||
|
|
ZSTDLIB_API ZSTD_DDict* ZSTD_createDDict(const void* dictBuffer, size_t dictSize);
|
||
|
|
|
||
|
|
/*! ZSTD_freeDDict() :
|
||
|
|
* Function frees memory allocated with ZSTD_createDDict() */
|
||
|
|
ZSTDLIB_API size_t ZSTD_freeDDict(ZSTD_DDict* ddict);
|
||
|
|
|
||
|
|
/*! ZSTD_decompress_usingDDict() :
|
||
|
|
* Decompression using a digested Dictionary.
|
||
|
|
* 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,
|
||
|
|
const ZSTD_DDict* ddict);
|
||
|
|
|
||
|
|
|
||
|
|
/********************************
|
||
|
|
* Dictionary helper functions
|
||
|
|
*******************************/
|
||
|
|
|
||
|
|
/*! ZSTD_getDictID_fromDict() :
|
||
|
|
* Provides the dictID stored within dictionary.
|
||
|
|
* if @return == 0, the dictionary is not conformant with Zstandard specification.
|
||
|
|
* It can still be loaded, but as a content-only dictionary. */
|
||
|
|
ZSTDLIB_API unsigned ZSTD_getDictID_fromDict(const void* dict, size_t dictSize);
|
||
|
|
|
||
|
|
/*! ZSTD_getDictID_fromDDict() :
|
||
|
|
* Provides the dictID of the dictionary loaded into `ddict`.
|
||
|
|
* If @return == 0, the dictionary is not conformant to Zstandard specification, or empty.
|
||
|
|
* Non-conformant dictionaries can still be loaded, but as content-only dictionaries. */
|
||
|
|
ZSTDLIB_API unsigned ZSTD_getDictID_fromDDict(const ZSTD_DDict* ddict);
|
||
|
|
|
||
|
|
/*! ZSTD_getDictID_fromFrame() :
|
||
|
|
* Provides the dictID required to decompressed the frame stored within `src`.
|
||
|
|
* If @return == 0, the dictID could not be decoded.
|
||
|
|
* This could for one of the following reasons :
|
||
|
|
* - The frame does not require a dictionary to be decoded (most common case).
|
||
|
|
* - The frame was built with dictID intentionally removed. Whatever dictionary is necessary is a hidden information.
|
||
|
|
* 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_getFrameHeader(), which will provide a more precise error code. */
|
||
|
|
ZSTDLIB_API unsigned ZSTD_getDictID_fromFrame(const void* src, size_t srcSize);
|
||
|
|
|
||
|
|
|
||
|
|
/*******************************************************************************
|
||
|
|
* Advanced dictionary and prefix API
|
||
|
|
*
|
||
|
|
* This API allows dictionaries to be used with ZSTD_compress2(),
|
||
|
|
* ZSTD_compressStream2(), and ZSTD_decompress(). Dictionaries are sticky, and
|
||
|
|
* only reset with the context is reset with ZSTD_reset_parameters or
|
||
|
|
* ZSTD_reset_session_and_parameters. Prefixes are single-use.
|
||
|
|
******************************************************************************/
|
||
|
|
|
||
|
|
|
||
|
|
/*! ZSTD_CCtx_loadDictionary() :
|
||
|
|
* Create an internal CDict from `dict` buffer.
|
||
|
|
* Decompression will have to use same dictionary.
|
||
|
|
* @result : 0, or an error code (which can be tested with ZSTD_isError()).
|
||
|
|
* Special: Loading a NULL (or 0-size) dictionary invalidates previous dictionary,
|
||
|
|
* meaning "return to no-dictionary mode".
|
||
|
|
* Note 1 : Dictionary is sticky, it will be used for all future compressed frames.
|
||
|
|
* To return to "no-dictionary" situation, load a NULL dictionary (or reset parameters).
|
||
|
|
* Note 2 : Loading a dictionary involves building tables.
|
||
|
|
* It's also a CPU consuming operation, with non-negligible impact on latency.
|
||
|
|
* Tables are dependent on compression parameters, and for this reason,
|
||
|
|
* compression parameters can no longer be changed after loading a dictionary.
|
||
|
|
* Note 3 :`dict` content will be copied internally.
|
||
|
|
* Use experimental ZSTD_CCtx_loadDictionary_byReference() to reference content instead.
|
||
|
|
* In such a case, dictionary buffer must outlive its users.
|
||
|
|
* Note 4 : Use ZSTD_CCtx_loadDictionary_advanced()
|
||
|
|
* to precisely select how dictionary content must be interpreted. */
|
||
|
|
ZSTDLIB_API size_t ZSTD_CCtx_loadDictionary(ZSTD_CCtx* cctx, const void* dict, size_t dictSize);
|
||
|
|
|
||
|
|
/*! ZSTD_CCtx_refCDict() :
|
||
|
|
* Reference a prepared dictionary, to be used for all next compressed frames.
|
||
|
|
* Note that compression parameters are enforced from within CDict,
|
||
|
|
* and supersede any compression parameter previously set within CCtx.
|
||
|
|
* The parameters ignored are labled as "superseded-by-cdict" in the ZSTD_cParameter enum docs.
|
||
|
|
* The ignored parameters will be used again if the CCtx is returned to no-dictionary mode.
|
||
|
|
* The dictionary will remain valid for future compressed frames using same CCtx.
|
||
|
|
* @result : 0, or an error code (which can be tested with ZSTD_isError()).
|
||
|
|
* Special : Referencing a NULL CDict means "return to no-dictionary mode".
|
||
|
|
* Note 1 : Currently, only one dictionary can be managed.
|
||
|
|
* Referencing a new dictionary effectively "discards" any previous one.
|
||
|
|
* Note 2 : CDict is just referenced, its lifetime must outlive its usage within 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 compressed frame.
|
||
|
|
* A prefix is **only used once**. Tables are discarded at end of frame (ZSTD_e_end).
|
||
|
|
* Decompression will need same prefix to properly regenerate data.
|
||
|
|
* Compressing with a prefix is similar in outcome as performing a diff and compressing it,
|
||
|
|
* but performs much faster, especially during decompression (compression speed is tunable with compression level).
|
||
|
|
* @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.
|
||
|
|
* Its content must remain unmodified during compression.
|
||
|
|
* Note 2 : If the intention is to diff some large src data blob with some prior version of itself,
|
||
|
|
* ensure that the window size is large enough to contain the entire source.
|
||
|
|
* See ZSTD_c_windowLog.
|
||
|
|
* Note 3 : Referencing a prefix involves building tables, which are dependent on compression parameters.
|
||
|
|
* It's a CPU consuming operation, with non-negligible impact on latency.
|
||
|
|
* If there is a need to use the same prefix multiple times, consider loadDictionary instead.
|
||
|
|
* Note 4 : By default, the prefix is interpreted as raw content (ZSTD_dct_rawContent).
|
||
|
|
* Use experimental ZSTD_CCtx_refPrefix_advanced() to alter dictionary interpretation. */
|
||
|
|
ZSTDLIB_API size_t ZSTD_CCtx_refPrefix(ZSTD_CCtx* cctx,
|
||
|
|
const void* prefix, size_t prefixSize);
|
||
|
|
|
||
|
|
/*! ZSTD_DCtx_loadDictionary() :
|
||
|
|
* Create an internal DDict from dict buffer,
|
||
|
|
* to be used to decompress next frames.
|
||
|
|
* The dictionary remains valid for all future frames, until explicitly invalidated.
|
||
|
|
* @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 : Loading a dictionary involves building tables,
|
||
|
|
* which has a non-negligible impact on CPU usage and latency.
|
||
|
|
* It's recommended to "load once, use many times", to amortize the cost
|
||
|
|
* Note 2 :`dict` content will be copied internally, so `dict` can be released after loading.
|
||
|
|
* Use ZSTD_DCtx_loadDictionary_byReference() to reference dictionary content instead.
|
||
|
|
* Note 3 : Use ZSTD_DCtx_loadDictionary_advanced() to take control of
|
||
|
|
* how dictionary content is loaded and interpreted.
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API size_t ZSTD_DCtx_loadDictionary(ZSTD_DCtx* dctx, const void* dict, size_t dictSize);
|
||
|
|
|
||
|
|
/*! 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: referencing 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);
|
||
|
|
|
||
|
|
/*! ZSTD_DCtx_refPrefix() :
|
||
|
|
* Reference a prefix (single-usage dictionary) to decompress next frame.
|
||
|
|
* This is the reverse operation of ZSTD_CCtx_refPrefix(),
|
||
|
|
* and must use the same prefix as the one used during compression.
|
||
|
|
* Prefix is **only used once**. Reference is discarded at end of frame.
|
||
|
|
* End of frame is reached when ZSTD_decompressStream() returns 0.
|
||
|
|
* @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 decompression.
|
||
|
|
* Prefix buffer must remain unmodified up to the end of frame,
|
||
|
|
* reached when ZSTD_decompressStream() returns 0.
|
||
|
|
* Note 3 : By default, the prefix is treated as raw content (ZSTD_dct_rawContent).
|
||
|
|
* Use ZSTD_CCtx_refPrefix_advanced() to alter dictMode (Experimental section)
|
||
|
|
* Note 4 : Referencing a raw content prefix has almost no cpu nor memory cost.
|
||
|
|
* A full dictionary is more costly, as it requires building tables.
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API size_t ZSTD_DCtx_refPrefix(ZSTD_DCtx* dctx,
|
||
|
|
const void* prefix, size_t prefixSize);
|
||
|
|
|
||
|
|
/* === Memory management === */
|
||
|
|
|
||
|
|
/*! ZSTD_sizeof_*() :
|
||
|
|
* These functions give the _current_ memory usage of selected object.
|
||
|
|
* Note that object memory usage can evolve (increase or decrease) over time. */
|
||
|
|
ZSTDLIB_API size_t ZSTD_sizeof_CCtx(const ZSTD_CCtx* cctx);
|
||
|
|
ZSTDLIB_API size_t ZSTD_sizeof_DCtx(const ZSTD_DCtx* dctx);
|
||
|
|
ZSTDLIB_API size_t ZSTD_sizeof_CStream(const ZSTD_CStream* zcs);
|
||
|
|
ZSTDLIB_API size_t ZSTD_sizeof_DStream(const ZSTD_DStream* zds);
|
||
|
|
ZSTDLIB_API size_t ZSTD_sizeof_CDict(const ZSTD_CDict* cdict);
|
||
|
|
ZSTDLIB_API size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict);
|
||
|
|
|
||
|
|
#endif /* ZSTD_H_235446 */
|
||
|
|
|
||
|
|
|
||
|
|
/* **************************************************************************************
|
||
|
|
* ADVANCED AND EXPERIMENTAL FUNCTIONS
|
||
|
|
****************************************************************************************
|
||
|
|
* The definitions in the following section are considered experimental.
|
||
|
|
* They are provided for advanced scenarios.
|
||
|
|
* They should never be used with a dynamic library, as prototypes may change in the future.
|
||
|
|
* 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
|
||
|
|
|
||
|
|
/****************************************************************************************
|
||
|
|
* experimental API (static linking only)
|
||
|
|
****************************************************************************************
|
||
|
|
* The following symbols and constants
|
||
|
|
* are not planned to join "stable API" status in the near future.
|
||
|
|
* They can still change in future versions.
|
||
|
|
* Some of them are planned to remain in the static_only section indefinitely.
|
||
|
|
* Some of them might be removed in the future (especially when redundant with existing stable functions)
|
||
|
|
* ***************************************************************************************/
|
||
|
|
|
||
|
|
#define ZSTD_FRAMEHEADERSIZE_PREFIX(format) ((format) == ZSTD_f_zstd1 ? 5 : 1) /* minimum input size required to query frame header size */
|
||
|
|
#define ZSTD_FRAMEHEADERSIZE_MIN(format) ((format) == ZSTD_f_zstd1 ? 6 : 2)
|
||
|
|
#define ZSTD_FRAMEHEADERSIZE_MAX 18 /* can be useful for static allocation */
|
||
|
|
#define ZSTD_SKIPPABLEHEADERSIZE 8
|
||
|
|
|
||
|
|
/* compression parameter bounds */
|
||
|
|
#define ZSTD_WINDOWLOG_MAX_32 30
|
||
|
|
#define ZSTD_WINDOWLOG_MAX_64 31
|
||
|
|
#define ZSTD_WINDOWLOG_MAX ((int)(sizeof(size_t) == 4 ? ZSTD_WINDOWLOG_MAX_32 : ZSTD_WINDOWLOG_MAX_64))
|
||
|
|
#define ZSTD_WINDOWLOG_MIN 10
|
||
|
|
#define ZSTD_HASHLOG_MAX ((ZSTD_WINDOWLOG_MAX < 30) ? ZSTD_WINDOWLOG_MAX : 30)
|
||
|
|
#define ZSTD_HASHLOG_MIN 6
|
||
|
|
#define ZSTD_CHAINLOG_MAX_32 29
|
||
|
|
#define ZSTD_CHAINLOG_MAX_64 30
|
||
|
|
#define ZSTD_CHAINLOG_MAX ((int)(sizeof(size_t) == 4 ? ZSTD_CHAINLOG_MAX_32 : ZSTD_CHAINLOG_MAX_64))
|
||
|
|
#define ZSTD_CHAINLOG_MIN ZSTD_HASHLOG_MIN
|
||
|
|
#define ZSTD_SEARCHLOG_MAX (ZSTD_WINDOWLOG_MAX-1)
|
||
|
|
#define ZSTD_SEARCHLOG_MIN 1
|
||
|
|
#define ZSTD_MINMATCH_MAX 7 /* only for ZSTD_fast, other strategies are limited to 6 */
|
||
|
|
#define ZSTD_MINMATCH_MIN 3 /* only for ZSTD_btopt+, faster strategies are limited to 4 */
|
||
|
|
#define ZSTD_TARGETLENGTH_MAX ZSTD_BLOCKSIZE_MAX
|
||
|
|
#define ZSTD_TARGETLENGTH_MIN 0 /* note : comparing this constant to an unsigned results in a tautological test */
|
||
|
|
#define ZSTD_STRATEGY_MIN ZSTD_fast
|
||
|
|
#define ZSTD_STRATEGY_MAX ZSTD_btultra2
|
||
|
|
|
||
|
|
|
||
|
|
#define ZSTD_OVERLAPLOG_MIN 0
|
||
|
|
#define ZSTD_OVERLAPLOG_MAX 9
|
||
|
|
|
||
|
|
#define ZSTD_WINDOWLOG_LIMIT_DEFAULT 27 /* by default, the streaming decoder will refuse any frame
|
||
|
|
* requiring larger than (1<<ZSTD_WINDOWLOG_LIMIT_DEFAULT) window size,
|
||
|
|
* to preserve host's memory from unreasonable requirements.
|
||
|
|
* This limit can be overridden using ZSTD_DCtx_setParameter(,ZSTD_d_windowLogMax,).
|
||
|
|
* The limit does not apply for one-pass decoders (such as ZSTD_decompress()), since no additional memory is allocated */
|
||
|
|
|
||
|
|
|
||
|
|
/* LDM parameter bounds */
|
||
|
|
#define ZSTD_LDM_HASHLOG_MIN ZSTD_HASHLOG_MIN
|
||
|
|
#define ZSTD_LDM_HASHLOG_MAX ZSTD_HASHLOG_MAX
|
||
|
|
#define ZSTD_LDM_MINMATCH_MIN 4
|
||
|
|
#define ZSTD_LDM_MINMATCH_MAX 4096
|
||
|
|
#define ZSTD_LDM_BUCKETSIZELOG_MIN 1
|
||
|
|
#define ZSTD_LDM_BUCKETSIZELOG_MAX 8
|
||
|
|
#define ZSTD_LDM_HASHRATELOG_MIN 0
|
||
|
|
#define ZSTD_LDM_HASHRATELOG_MAX (ZSTD_WINDOWLOG_MAX - ZSTD_HASHLOG_MIN)
|
||
|
|
|
||
|
|
/* Advanced parameter bounds */
|
||
|
|
#define ZSTD_TARGETCBLOCKSIZE_MIN 64
|
||
|
|
#define ZSTD_TARGETCBLOCKSIZE_MAX ZSTD_BLOCKSIZE_MAX
|
||
|
|
#define ZSTD_SRCSIZEHINT_MIN 0
|
||
|
|
#define ZSTD_SRCSIZEHINT_MAX INT_MAX
|
||
|
|
|
||
|
|
/* internal */
|
||
|
|
#define ZSTD_HASHLOG3_MAX 17
|
||
|
|
|
||
|
|
|
||
|
|
/* --- Advanced types --- */
|
||
|
|
|
||
|
|
typedef struct ZSTD_CCtx_params_s ZSTD_CCtx_params;
|
||
|
|
|
||
|
|
typedef struct {
|
||
|
|
unsigned int matchPos; /* Match pos in dst */
|
||
|
|
/* If seqDef.offset > 3, then this is seqDef.offset - 3
|
||
|
|
* If seqDef.offset < 3, then this is the corresponding repeat offset
|
||
|
|
* But if seqDef.offset < 3 and litLength == 0, this is the
|
||
|
|
* repeat offset before the corresponding repeat offset
|
||
|
|
* And if seqDef.offset == 3 and litLength == 0, this is the
|
||
|
|
* most recent repeat offset - 1
|
||
|
|
*/
|
||
|
|
unsigned int offset;
|
||
|
|
unsigned int litLength; /* Literal length */
|
||
|
|
unsigned int matchLength; /* Match length */
|
||
|
|
/* 0 when seq not rep and seqDef.offset otherwise
|
||
|
|
* when litLength == 0 this will be <= 4, otherwise <= 3 like normal
|
||
|
|
*/
|
||
|
|
unsigned int rep;
|
||
|
|
} ZSTD_Sequence;
|
||
|
|
|
||
|
|
typedef struct {
|
||
|
|
unsigned windowLog; /**< largest match distance : larger == more compression, more memory needed during decompression */
|
||
|
|
unsigned chainLog; /**< fully searched segment : larger == more compression, slower, more memory (useless for fast) */
|
||
|
|
unsigned hashLog; /**< dispatch table : larger == faster, more memory */
|
||
|
|
unsigned searchLog; /**< nb of searches : larger == more compression, slower */
|
||
|
|
unsigned minMatch; /**< match length searched : larger == faster decompression, sometimes less compression */
|
||
|
|
unsigned targetLength; /**< acceptable match size for optimal parser (only) : larger == more compression, slower */
|
||
|
|
ZSTD_strategy strategy; /**< see ZSTD_strategy definition above */
|
||
|
|
} ZSTD_compressionParameters;
|
||
|
|
|
||
|
|
typedef struct {
|
||
|
|
int contentSizeFlag; /**< 1: content size will be in frame header (when known) */
|
||
|
|
int checksumFlag; /**< 1: generate a 32-bits checksum using XXH64 algorithm at end of frame, for error detection */
|
||
|
|
int noDictIDFlag; /**< 1: no dictID will be saved into frame header (dictID is only useful for dictionary compression) */
|
||
|
|
} ZSTD_frameParameters;
|
||
|
|
|
||
|
|
typedef struct {
|
||
|
|
ZSTD_compressionParameters cParams;
|
||
|
|
ZSTD_frameParameters fParams;
|
||
|
|
} ZSTD_parameters;
|
||
|
|
|
||
|
|
typedef enum {
|
||
|
|
ZSTD_dct_auto = 0, /* dictionary is "full" when starting with ZSTD_MAGIC_DICTIONARY, otherwise it is "rawContent" */
|
||
|
|
ZSTD_dct_rawContent = 1, /* ensures dictionary is always loaded as rawContent, even if it starts with ZSTD_MAGIC_DICTIONARY */
|
||
|
|
ZSTD_dct_fullDict = 2 /* refuses to load a dictionary if it does not respect Zstandard's specification, starting with ZSTD_MAGIC_DICTIONARY */
|
||
|
|
} ZSTD_dictContentType_e;
|
||
|
|
|
||
|
|
typedef enum {
|
||
|
|
ZSTD_dlm_byCopy = 0, /**< Copy dictionary content internally */
|
||
|
|
ZSTD_dlm_byRef = 1 /**< Reference dictionary content -- the dictionary buffer must outlive its users. */
|
||
|
|
} ZSTD_dictLoadMethod_e;
|
||
|
|
|
||
|
|
typedef enum {
|
||
|
|
ZSTD_f_zstd1 = 0, /* zstd frame format, specified in zstd_compression_format.md (default) */
|
||
|
|
ZSTD_f_zstd1_magicless = 1 /* Variant of zstd frame format, without initial 4-bytes magic number.
|
||
|
|
* Useful to save 4 bytes per generated frame.
|
||
|
|
* Decoder cannot recognise automatically this format, requiring this instruction. */
|
||
|
|
} ZSTD_format_e;
|
||
|
|
|
||
|
|
typedef enum {
|
||
|
|
/* Note: this enum and the behavior it controls are effectively internal
|
||
|
|
* implementation details of the compressor. They are expected to continue
|
||
|
|
* to evolve and should be considered only in the context of extremely
|
||
|
|
* advanced performance tuning.
|
||
|
|
*
|
||
|
|
* Zstd currently supports the use of a CDict in three ways:
|
||
|
|
*
|
||
|
|
* - The contents of the CDict can be copied into the working context. This
|
||
|
|
* means that the compression can search both the dictionary and input
|
||
|
|
* while operating on a single set of internal tables. This makes
|
||
|
|
* the compression faster per-byte of input. However, the initial copy of
|
||
|
|
* the CDict's tables incurs a fixed cost at the beginning of the
|
||
|
|
* compression. For small compressions (< 8 KB), that copy can dominate
|
||
|
|
* the cost of the compression.
|
||
|
|
*
|
||
|
|
* - The CDict's tables can be used in-place. In this model, compression is
|
||
|
|
* slower per input byte, because the compressor has to search two sets of
|
||
|
|
* tables. However, this model incurs no start-up cost (as long as the
|
||
|
|
* working context's tables can be reused). For small inputs, this can be
|
||
|
|
* faster than copying the CDict's tables.
|
||
|
|
*
|
||
|
|
* - The CDict's tables are not used at all, and instead we use the working
|
||
|
|
* context alone to reload the dictionary and use params based on the source
|
||
|
|
* size. See ZSTD_compress_insertDictionary() and ZSTD_compress_usingDict().
|
||
|
|
* This method is effective when the dictionary sizes are very small relative
|
||
|
|
* to the input size, and the input size is fairly large to begin with.
|
||
|
|
*
|
||
|
|
* Zstd has a simple internal heuristic that selects which strategy to use
|
||
|
|
* at the beginning of a compression. However, if experimentation shows that
|
||
|
|
* Zstd is making poor choices, it is possible to override that choice with
|
||
|
|
* this enum.
|
||
|
|
*/
|
||
|
|
ZSTD_dictDefaultAttach = 0, /* Use the default heuristic. */
|
||
|
|
ZSTD_dictForceAttach = 1, /* Never copy the dictionary. */
|
||
|
|
ZSTD_dictForceCopy = 2, /* Always copy the dictionary. */
|
||
|
|
ZSTD_dictForceLoad = 3 /* Always reload the dictionary */
|
||
|
|
} ZSTD_dictAttachPref_e;
|
||
|
|
|
||
|
|
typedef enum {
|
||
|
|
ZSTD_lcm_auto = 0, /**< Automatically determine the compression mode based on the compression level.
|
||
|
|
* Negative compression levels will be uncompressed, and positive compression
|
||
|
|
* levels will be compressed. */
|
||
|
|
ZSTD_lcm_huffman = 1, /**< Always attempt Huffman compression. Uncompressed literals will still be
|
||
|
|
* emitted if Huffman compression is not profitable. */
|
||
|
|
ZSTD_lcm_uncompressed = 2 /**< Always emit uncompressed literals. */
|
||
|
|
} ZSTD_literalCompressionMode_e;
|
||
|
|
|
||
|
|
|
||
|
|
/***************************************
|
||
|
|
* Frame size functions
|
||
|
|
***************************************/
|
||
|
|
|
||
|
|
/*! ZSTD_findDecompressedSize() :
|
||
|
|
* `src` should point to 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 at `src + srcSize`)
|
||
|
|
* @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
|
||
|
|
*
|
||
|
|
* 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.
|
||
|
|
* 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.
|
||
|
|
* 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.
|
||
|
|
* 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 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_decompressBound() :
|
||
|
|
* `src` should point to 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 at `src + srcSize`)
|
||
|
|
* @return : - upper-bound for the decompressed size of all data in all successive frames
|
||
|
|
* - if an error occured: ZSTD_CONTENTSIZE_ERROR
|
||
|
|
*
|
||
|
|
* note 1 : an error can occur if `src` contains an invalid or incorrectly formatted frame.
|
||
|
|
* note 2 : the upper-bound is exact when the decompressed size field is available in every ZSTD encoded frame of `src`.
|
||
|
|
* in this case, `ZSTD_findDecompressedSize` and `ZSTD_decompressBound` return the same value.
|
||
|
|
* note 3 : when the decompressed size field isn't available, the upper-bound for that frame is calculated by:
|
||
|
|
* upper-bound = # blocks * min(128 KB, Window_Size)
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API unsigned long long ZSTD_decompressBound(const void* src, size_t srcSize);
|
||
|
|
|
||
|
|
/*! ZSTD_frameHeaderSize() :
|
||
|
|
* srcSize must be >= ZSTD_FRAMEHEADERSIZE_PREFIX.
|
||
|
|
* @return : size of the Frame Header,
|
||
|
|
* or an error code (if srcSize is too small) */
|
||
|
|
ZSTDLIB_API size_t ZSTD_frameHeaderSize(const void* src, size_t srcSize);
|
||
|
|
|
||
|
|
/*! ZSTD_getSequences() :
|
||
|
|
* Extract sequences from the sequence store
|
||
|
|
* zc can be used to insert custom compression params.
|
||
|
|
* This function invokes ZSTD_compress2
|
||
|
|
* @return : number of sequences extracted
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API size_t ZSTD_getSequences(ZSTD_CCtx* zc, ZSTD_Sequence* outSeqs,
|
||
|
|
size_t outSeqsSize, const void* src, size_t srcSize);
|
||
|
|
|
||
|
|
|
||
|
|
/***************************************
|
||
|
|
* Memory management
|
||
|
|
***************************************/
|
||
|
|
|
||
|
|
/*! ZSTD_estimate*() :
|
||
|
|
* These functions make it possible to estimate memory usage
|
||
|
|
* of a future {D,C}Ctx, before its creation.
|
||
|
|
*
|
||
|
|
* ZSTD_estimateCCtxSize() will provide a memory budget large enough
|
||
|
|
* for any compression level up to selected one.
|
||
|
|
* Note : Unlike ZSTD_estimateCStreamSize*(), this estimate
|
||
|
|
* does not include space for a window buffer.
|
||
|
|
* Therefore, the estimation is only guaranteed for single-shot compressions, not streaming.
|
||
|
|
* The estimate will assume the input may be arbitrarily large,
|
||
|
|
* which is the worst case.
|
||
|
|
*
|
||
|
|
* When srcSize can be bound by a known and rather "small" value,
|
||
|
|
* this fact can be used to provide a tighter estimation
|
||
|
|
* because the CCtx compression context will need less memory.
|
||
|
|
* This tighter estimation can be provided by more advanced functions
|
||
|
|
* ZSTD_estimateCCtxSize_usingCParams(), which can be used in tandem with ZSTD_getCParams(),
|
||
|
|
* and ZSTD_estimateCCtxSize_usingCCtxParams(), which can be used in tandem with ZSTD_CCtxParams_setParameter().
|
||
|
|
* Both can be used to estimate memory using custom compression parameters and arbitrary srcSize limits.
|
||
|
|
*
|
||
|
|
* Note 2 : only single-threaded compression is supported.
|
||
|
|
* ZSTD_estimateCCtxSize_usingCCtxParams() will return an error code if ZSTD_c_nbWorkers is >= 1.
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API size_t ZSTD_estimateCCtxSize(int compressionLevel);
|
||
|
|
ZSTDLIB_API size_t ZSTD_estimateCCtxSize_usingCParams(ZSTD_compressionParameters cParams);
|
||
|
|
ZSTDLIB_API size_t ZSTD_estimateCCtxSize_usingCCtxParams(const ZSTD_CCtx_params* params);
|
||
|
|
ZSTDLIB_API size_t ZSTD_estimateDCtxSize(void);
|
||
|
|
|
||
|
|
/*! 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_usingCParams() can provide a tighter estimation.
|
||
|
|
* ZSTD_estimateCStreamSize_usingCParams() can be used in tandem with ZSTD_getCParams() to create cParams from compressionLevel.
|
||
|
|
* ZSTD_estimateCStreamSize_usingCCtxParams() can be used in tandem with ZSTD_CCtxParams_setParameter(). Only single-threaded compression is supported. This function will return an error code if ZSTD_c_nbWorkers is >= 1.
|
||
|
|
* Note : CStream size 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 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_usingCParams(ZSTD_compressionParameters cParams);
|
||
|
|
ZSTDLIB_API size_t ZSTD_estimateCStreamSize_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);
|
||
|
|
|
||
|
|
/*! ZSTD_estimate?DictSize() :
|
||
|
|
* ZSTD_estimateCDictSize() will bet that src size is relatively "small", and content is copied, like ZSTD_createCDict().
|
||
|
|
* ZSTD_estimateCDictSize_advanced() makes it possible to control compression parameters precisely, like ZSTD_createCDict_advanced().
|
||
|
|
* Note : dictionaries created by reference (`ZSTD_dlm_byRef`) are logically 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);
|
||
|
|
|
||
|
|
/*! ZSTD_initStatic*() :
|
||
|
|
* Initialize an object using a pre-allocated fixed-size buffer.
|
||
|
|
* workspace: The memory area to emplace the object into.
|
||
|
|
* Provided pointer *must be 8-bytes aligned*.
|
||
|
|
* Buffer must outlive object.
|
||
|
|
* workspaceSize: Use ZSTD_estimate*Size() to determine
|
||
|
|
* how large workspace must be to support target scenario.
|
||
|
|
* @return : pointer to object (same address as workspace, just different type),
|
||
|
|
* or NULL if error (size too small, incorrect alignment, etc.)
|
||
|
|
* Note : zstd will never resize nor malloc() when using a static buffer.
|
||
|
|
* If the object requires more memory than available,
|
||
|
|
* zstd will just error out (typically ZSTD_error_memory_allocation).
|
||
|
|
* Note 2 : there is no corresponding "free" function.
|
||
|
|
* Since workspace is allocated externally, it must be freed externally too.
|
||
|
|
* Note 3 : cParams : use ZSTD_getCParams() to convert a compression level
|
||
|
|
* into its associated cParams.
|
||
|
|
* Limitation 1 : currently not compatible with internal dictionary creation, triggered by
|
||
|
|
* ZSTD_CCtx_loadDictionary(), ZSTD_initCStream_usingDict() or ZSTD_initDStream_usingDict().
|
||
|
|
* Limitation 2 : static cctx currently not compatible with multi-threading.
|
||
|
|
* Limitation 3 : static dctx is incompatible with legacy support.
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API ZSTD_CCtx* ZSTD_initStaticCCtx(void* workspace, size_t workspaceSize);
|
||
|
|
ZSTDLIB_API ZSTD_CStream* ZSTD_initStaticCStream(void* workspace, size_t workspaceSize); /**< same as ZSTD_initStaticCCtx() */
|
||
|
|
|
||
|
|
ZSTDLIB_API ZSTD_DCtx* ZSTD_initStaticDCtx(void* workspace, size_t workspaceSize);
|
||
|
|
ZSTDLIB_API ZSTD_DStream* ZSTD_initStaticDStream(void* workspace, size_t workspaceSize); /**< same as ZSTD_initStaticDCtx() */
|
||
|
|
|
||
|
|
ZSTDLIB_API const ZSTD_CDict* ZSTD_initStaticCDict(
|
||
|
|
void* workspace, size_t workspaceSize,
|
||
|
|
const void* dict, size_t dictSize,
|
||
|
|
ZSTD_dictLoadMethod_e dictLoadMethod,
|
||
|
|
ZSTD_dictContentType_e dictContentType,
|
||
|
|
ZSTD_compressionParameters cParams);
|
||
|
|
|
||
|
|
ZSTDLIB_API const ZSTD_DDict* ZSTD_initStaticDDict(
|
||
|
|
void* workspace, size_t workspaceSize,
|
||
|
|
const void* dict, size_t dictSize,
|
||
|
|
ZSTD_dictLoadMethod_e dictLoadMethod,
|
||
|
|
ZSTD_dictContentType_e dictContentType);
|
||
|
|
|
||
|
|
|
||
|
|
/*! Custom memory allocation :
|
||
|
|
* These prototypes make it possible to pass your own allocation/free functions.
|
||
|
|
* ZSTD_customMem is provided at creation time, using ZSTD_create*_advanced() variants listed below.
|
||
|
|
* All allocation/free operations will be completed using these custom variants instead of regular <stdlib.h> ones.
|
||
|
|
*/
|
||
|
|
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;
|
||
|
|
static ZSTD_customMem const ZSTD_defaultCMem = { NULL, NULL, NULL }; /**< this constant defers to stdlib's functions */
|
||
|
|
|
||
|
|
ZSTDLIB_API ZSTD_CCtx* ZSTD_createCCtx_advanced(ZSTD_customMem customMem);
|
||
|
|
ZSTDLIB_API ZSTD_CStream* ZSTD_createCStream_advanced(ZSTD_customMem customMem);
|
||
|
|
ZSTDLIB_API ZSTD_DCtx* ZSTD_createDCtx_advanced(ZSTD_customMem customMem);
|
||
|
|
ZSTDLIB_API ZSTD_DStream* ZSTD_createDStream_advanced(ZSTD_customMem customMem);
|
||
|
|
|
||
|
|
ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict_advanced(const void* dict, size_t dictSize,
|
||
|
|
ZSTD_dictLoadMethod_e dictLoadMethod,
|
||
|
|
ZSTD_dictContentType_e dictContentType,
|
||
|
|
ZSTD_compressionParameters cParams,
|
||
|
|
ZSTD_customMem customMem);
|
||
|
|
|
||
|
|
ZSTDLIB_API ZSTD_DDict* ZSTD_createDDict_advanced(const void* dict, size_t dictSize,
|
||
|
|
ZSTD_dictLoadMethod_e dictLoadMethod,
|
||
|
|
ZSTD_dictContentType_e dictContentType,
|
||
|
|
ZSTD_customMem customMem);
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
/***************************************
|
||
|
|
* Advanced compression functions
|
||
|
|
***************************************/
|
||
|
|
|
||
|
|
/*! ZSTD_createCDict_byReference() :
|
||
|
|
* Create a digested dictionary for compression
|
||
|
|
* Dictionary content is just referenced, not duplicated.
|
||
|
|
* As a consequence, `dictBuffer` **must** outlive CDict,
|
||
|
|
* and its content must remain unmodified throughout the lifetime of CDict.
|
||
|
|
* note: equivalent to ZSTD_createCDict_advanced(), with dictLoadMethod==ZSTD_dlm_byRef */
|
||
|
|
ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict_byReference(const void* dictBuffer, size_t dictSize, int compressionLevel);
|
||
|
|
|
||
|
|
/*! ZSTD_getCParams() :
|
||
|
|
* @return ZSTD_compressionParameters structure for a selected compression level and estimated srcSize.
|
||
|
|
* `estimatedSrcSize` value is optional, select 0 if not known */
|
||
|
|
ZSTDLIB_API ZSTD_compressionParameters ZSTD_getCParams(int compressionLevel, unsigned long long estimatedSrcSize, size_t dictSize);
|
||
|
|
|
||
|
|
/*! ZSTD_getParams() :
|
||
|
|
* same as ZSTD_getCParams(), but @return a full `ZSTD_parameters` object instead of sub-component `ZSTD_compressionParameters`.
|
||
|
|
* All fields of `ZSTD_frameParameters` are set to default : contentSize=1, checksum=0, noDictID=0 */
|
||
|
|
ZSTDLIB_API ZSTD_parameters ZSTD_getParams(int compressionLevel, unsigned long long estimatedSrcSize, size_t dictSize);
|
||
|
|
|
||
|
|
/*! ZSTD_checkCParams() :
|
||
|
|
* Ensure param values remain within authorized range.
|
||
|
|
* @return 0 on success, or an error code (can be checked with ZSTD_isError()) */
|
||
|
|
ZSTDLIB_API size_t ZSTD_checkCParams(ZSTD_compressionParameters params);
|
||
|
|
|
||
|
|
/*! ZSTD_adjustCParams() :
|
||
|
|
* optimize params for a given `srcSize` and `dictSize`.
|
||
|
|
* `srcSize` can be unknown, in which case use ZSTD_CONTENTSIZE_UNKNOWN.
|
||
|
|
* `dictSize` must be `0` when there is no dictionary.
|
||
|
|
* cPar can be invalid : all parameters will be clamped within valid range in the @return struct.
|
||
|
|
* This function never fails (wide contract) */
|
||
|
|
ZSTDLIB_API ZSTD_compressionParameters ZSTD_adjustCParams(ZSTD_compressionParameters cPar, unsigned long long srcSize, size_t dictSize);
|
||
|
|
|
||
|
|
/*! ZSTD_compress_advanced() :
|
||
|
|
* Note : this function is now DEPRECATED.
|
||
|
|
* It can be replaced by ZSTD_compress2(), in combination with ZSTD_CCtx_setParameter() and other parameter setters.
|
||
|
|
* This prototype will be marked as deprecated and generate compilation warning on reaching v1.5.x */
|
||
|
|
ZSTDLIB_API size_t ZSTD_compress_advanced(ZSTD_CCtx* cctx,
|
||
|
|
void* dst, size_t dstCapacity,
|
||
|
|
const void* src, size_t srcSize,
|
||
|
|
const void* dict,size_t dictSize,
|
||
|
|
ZSTD_parameters params);
|
||
|
|
|
||
|
|
/*! ZSTD_compress_usingCDict_advanced() :
|
||
|
|
* Note : this function is now REDUNDANT.
|
||
|
|
* It can be replaced by ZSTD_compress2(), in combination with ZSTD_CCtx_loadDictionary() and other parameter setters.
|
||
|
|
* This prototype will be marked as deprecated and generate compilation warning in some future version */
|
||
|
|
ZSTDLIB_API size_t ZSTD_compress_usingCDict_advanced(ZSTD_CCtx* cctx,
|
||
|
|
void* dst, size_t dstCapacity,
|
||
|
|
const void* src, size_t srcSize,
|
||
|
|
const ZSTD_CDict* cdict,
|
||
|
|
ZSTD_frameParameters fParams);
|
||
|
|
|
||
|
|
|
||
|
|
/*! ZSTD_CCtx_loadDictionary_byReference() :
|
||
|
|
* Same as ZSTD_CCtx_loadDictionary(), but dictionary content is referenced, instead of being copied into CCtx.
|
||
|
|
* It saves some memory, but also requires that `dict` outlives its usage within `cctx` */
|
||
|
|
ZSTDLIB_API size_t ZSTD_CCtx_loadDictionary_byReference(ZSTD_CCtx* cctx, const void* dict, size_t dictSize);
|
||
|
|
|
||
|
|
/*! ZSTD_CCtx_loadDictionary_advanced() :
|
||
|
|
* Same as ZSTD_CCtx_loadDictionary(), but gives finer control over
|
||
|
|
* how to load the dictionary (by copy ? by reference ?)
|
||
|
|
* and how to interpret it (automatic ? force raw mode ? full mode only ?) */
|
||
|
|
ZSTDLIB_API size_t ZSTD_CCtx_loadDictionary_advanced(ZSTD_CCtx* cctx, const void* dict, size_t dictSize, ZSTD_dictLoadMethod_e dictLoadMethod, ZSTD_dictContentType_e dictContentType);
|
||
|
|
|
||
|
|
/*! ZSTD_CCtx_refPrefix_advanced() :
|
||
|
|
* Same as ZSTD_CCtx_refPrefix(), but gives finer control over
|
||
|
|
* how to interpret prefix content (automatic ? force raw mode (default) ? full mode only ?) */
|
||
|
|
ZSTDLIB_API size_t ZSTD_CCtx_refPrefix_advanced(ZSTD_CCtx* cctx, const void* prefix, size_t prefixSize, ZSTD_dictContentType_e dictContentType);
|
||
|
|
|
||
|
|
/* === experimental parameters === */
|
||
|
|
/* these parameters can be used with ZSTD_setParameter()
|
||
|
|
* they are not guaranteed to remain supported in the future */
|
||
|
|
|
||
|
|
/* Enables rsyncable mode,
|
||
|
|
* which makes compressed files more rsync friendly
|
||
|
|
* by adding periodic synchronization points to the compressed data.
|
||
|
|
* The target average block size is ZSTD_c_jobSize / 2.
|
||
|
|
* It's possible to modify the job size to increase or decrease
|
||
|
|
* the granularity of the synchronization point.
|
||
|
|
* Once the jobSize is smaller than the window size,
|
||
|
|
* it will result in compression ratio degradation.
|
||
|
|
* NOTE 1: rsyncable mode only works when multithreading is enabled.
|
||
|
|
* NOTE 2: rsyncable performs poorly in combination with long range mode,
|
||
|
|
* since it will decrease the effectiveness of synchronization points,
|
||
|
|
* though mileage may vary.
|
||
|
|
* NOTE 3: Rsyncable mode limits maximum compression speed to ~400 MB/s.
|
||
|
|
* If the selected compression level is already running significantly slower,
|
||
|
|
* the overall speed won't be significantly impacted.
|
||
|
|
*/
|
||
|
|
#define ZSTD_c_rsyncable ZSTD_c_experimentalParam1
|
||
|
|
|
||
|
|
/* Select a compression format.
|
||
|
|
* The value must be of type ZSTD_format_e.
|
||
|
|
* See ZSTD_format_e enum definition for details */
|
||
|
|
#define ZSTD_c_format ZSTD_c_experimentalParam2
|
||
|
|
|
||
|
|
/* Force back-reference distances to remain < windowSize,
|
||
|
|
* even when referencing into Dictionary content (default:0) */
|
||
|
|
#define ZSTD_c_forceMaxWindow ZSTD_c_experimentalParam3
|
||
|
|
|
||
|
|
/* Controls whether the contents of a CDict
|
||
|
|
* are used in place, or copied into the working context.
|
||
|
|
* Accepts values from the ZSTD_dictAttachPref_e enum.
|
||
|
|
* See the comments on that enum for an explanation of the feature. */
|
||
|
|
#define ZSTD_c_forceAttachDict ZSTD_c_experimentalParam4
|
||
|
|
|
||
|
|
/* Controls how the literals are compressed (default is auto).
|
||
|
|
* The value must be of type ZSTD_literalCompressionMode_e.
|
||
|
|
* See ZSTD_literalCompressionMode_t enum definition for details.
|
||
|
|
*/
|
||
|
|
#define ZSTD_c_literalCompressionMode ZSTD_c_experimentalParam5
|
||
|
|
|
||
|
|
/* Tries to fit compressed block size to be around targetCBlockSize.
|
||
|
|
* No target when targetCBlockSize == 0.
|
||
|
|
* There is no guarantee on compressed block size (default:0) */
|
||
|
|
#define ZSTD_c_targetCBlockSize ZSTD_c_experimentalParam6
|
||
|
|
|
||
|
|
/* User's best guess of source size.
|
||
|
|
* Hint is not valid when srcSizeHint == 0.
|
||
|
|
* There is no guarantee that hint is close to actual source size,
|
||
|
|
* but compression ratio may regress significantly if guess considerably underestimates */
|
||
|
|
#define ZSTD_c_srcSizeHint ZSTD_c_experimentalParam7
|
||
|
|
|
||
|
|
/*! ZSTD_CCtx_getParameter() :
|
||
|
|
* Get the requested compression parameter value, selected by enum ZSTD_cParameter,
|
||
|
|
* and store it into int* value.
|
||
|
|
* @return : 0, or an error code (which can be tested with ZSTD_isError()).
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API size_t ZSTD_CCtx_getParameter(ZSTD_CCtx* cctx, ZSTD_cParameter param, int* value);
|
||
|
|
|
||
|
|
|
||
|
|
/*! ZSTD_CCtx_params :
|
||
|
|
* Quick howto :
|
||
|
|
* - ZSTD_createCCtxParams() : Create a ZSTD_CCtx_params structure
|
||
|
|
* - ZSTD_CCtxParams_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 frames.
|
||
|
|
* - ZSTD_compressStream2() : Do compression using the CCtx.
|
||
|
|
* - ZSTD_freeCCtxParams() : Free the memory.
|
||
|
|
*
|
||
|
|
* This can be used with ZSTD_estimateCCtxSize_advanced_usingCCtxParams()
|
||
|
|
* for static allocation of CCtx for single-threaded compression.
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API ZSTD_CCtx_params* ZSTD_createCCtxParams(void);
|
||
|
|
ZSTDLIB_API size_t ZSTD_freeCCtxParams(ZSTD_CCtx_params* params);
|
||
|
|
|
||
|
|
/*! ZSTD_CCtxParams_reset() :
|
||
|
|
* Reset params to default values.
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API size_t ZSTD_CCtxParams_reset(ZSTD_CCtx_params* params);
|
||
|
|
|
||
|
|
/*! ZSTD_CCtxParams_init() :
|
||
|
|
* Initializes the compression parameters of cctxParams according to
|
||
|
|
* compression level. All other parameters are reset to their default values.
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API size_t ZSTD_CCtxParams_init(ZSTD_CCtx_params* cctxParams, int compressionLevel);
|
||
|
|
|
||
|
|
/*! ZSTD_CCtxParams_init_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_CCtxParams_init_advanced(ZSTD_CCtx_params* cctxParams, ZSTD_parameters params);
|
||
|
|
|
||
|
|
/*! ZSTD_CCtxParams_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().
|
||
|
|
* @result : 0, or an error code (which can be tested with ZSTD_isError()).
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API size_t ZSTD_CCtxParams_setParameter(ZSTD_CCtx_params* params, ZSTD_cParameter param, int value);
|
||
|
|
|
||
|
|
/*! ZSTD_CCtxParams_getParameter() :
|
||
|
|
* Similar to ZSTD_CCtx_getParameter.
|
||
|
|
* Get the requested value of one compression parameter, selected by enum ZSTD_cParameter.
|
||
|
|
* @result : 0, or an error code (which can be tested with ZSTD_isError()).
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API size_t ZSTD_CCtxParams_getParameter(ZSTD_CCtx_params* params, ZSTD_cParameter param, int* value);
|
||
|
|
|
||
|
|
/*! ZSTD_CCtx_setParametersUsingCCtxParams() :
|
||
|
|
* Apply a set of ZSTD_CCtx_params to the compression context.
|
||
|
|
* This can be done even after compression is started,
|
||
|
|
* if nbWorkers==0, this will have no impact until a new compression is started.
|
||
|
|
* if nbWorkers>=1, new parameters will be picked up at next job,
|
||
|
|
* with a few restrictions (windowLog, pledgedSrcSize, nbWorkers, jobSize, and overlapLog are not updated).
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API size_t ZSTD_CCtx_setParametersUsingCCtxParams(
|
||
|
|
ZSTD_CCtx* cctx, const ZSTD_CCtx_params* params);
|
||
|
|
|
||
|
|
/*! ZSTD_compressStream2_simpleArgs() :
|
||
|
|
* Same as ZSTD_compressStream2(),
|
||
|
|
* but using only integral types as arguments.
|
||
|
|
* This variant might be helpful for binders from dynamic languages
|
||
|
|
* which have troubles handling structures containing memory pointers.
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API size_t ZSTD_compressStream2_simpleArgs (
|
||
|
|
ZSTD_CCtx* cctx,
|
||
|
|
void* dst, size_t dstCapacity, size_t* dstPos,
|
||
|
|
const void* src, size_t srcSize, size_t* srcPos,
|
||
|
|
ZSTD_EndDirective endOp);
|
||
|
|
|
||
|
|
|
||
|
|
/***************************************
|
||
|
|
* Advanced decompression functions
|
||
|
|
***************************************/
|
||
|
|
|
||
|
|
/*! ZSTD_isFrame() :
|
||
|
|
* Tells if the content of `buffer` starts with a valid Frame Identifier.
|
||
|
|
* Note : Frame Identifier is 4 bytes. If `size < 4`, @return will always be 0.
|
||
|
|
* Note 2 : Legacy Frame Identifiers are considered valid only if Legacy Support is enabled.
|
||
|
|
* Note 3 : Skippable Frame Identifiers are considered valid. */
|
||
|
|
ZSTDLIB_API unsigned ZSTD_isFrame(const void* buffer, size_t size);
|
||
|
|
|
||
|
|
/*! ZSTD_createDDict_byReference() :
|
||
|
|
* Create a digested dictionary, ready to start decompression operation without startup delay.
|
||
|
|
* 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_DCtx_loadDictionary_byReference() :
|
||
|
|
* Same as ZSTD_DCtx_loadDictionary(),
|
||
|
|
* but references `dict` content instead of copying it into `dctx`.
|
||
|
|
* This saves memory if `dict` remains around.,
|
||
|
|
* However, it's imperative that `dict` remains accessible (and unmodified) while being used, so it must outlive decompression. */
|
||
|
|
ZSTDLIB_API size_t ZSTD_DCtx_loadDictionary_byReference(ZSTD_DCtx* dctx, const void* dict, size_t dictSize);
|
||
|
|
|
||
|
|
/*! ZSTD_DCtx_loadDictionary_advanced() :
|
||
|
|
* Same as ZSTD_DCtx_loadDictionary(),
|
||
|
|
* but gives direct control over
|
||
|
|
* how to load the dictionary (by copy ? by reference ?)
|
||
|
|
* and how to interpret it (automatic ? force raw mode ? full mode only ?). */
|
||
|
|
ZSTDLIB_API size_t ZSTD_DCtx_loadDictionary_advanced(ZSTD_DCtx* dctx, const void* dict, size_t dictSize, ZSTD_dictLoadMethod_e dictLoadMethod, ZSTD_dictContentType_e dictContentType);
|
||
|
|
|
||
|
|
/*! ZSTD_DCtx_refPrefix_advanced() :
|
||
|
|
* Same as ZSTD_DCtx_refPrefix(), but gives finer control over
|
||
|
|
* how to interpret prefix content (automatic ? force raw mode (default) ? full mode only ?) */
|
||
|
|
ZSTDLIB_API size_t ZSTD_DCtx_refPrefix_advanced(ZSTD_DCtx* dctx, const void* prefix, size_t prefixSize, ZSTD_dictContentType_e dictContentType);
|
||
|
|
|
||
|
|
/*! ZSTD_DCtx_setMaxWindowSize() :
|
||
|
|
* Refuses allocating internal buffers for frames requiring a window size larger than provided limit.
|
||
|
|
* This protects 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 single-pass mode.
|
||
|
|
* By default, a decompression context accepts all window sizes <= (1 << ZSTD_WINDOWLOG_LIMIT_DEFAULT)
|
||
|
|
* @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_d_format
|
||
|
|
* experimental parameter,
|
||
|
|
* allowing selection between ZSTD_format_e input compression formats
|
||
|
|
*/
|
||
|
|
#define ZSTD_d_format ZSTD_d_experimentalParam1
|
||
|
|
/* ZSTD_d_stableOutBuffer
|
||
|
|
* Experimental parameter.
|
||
|
|
* Default is 0 == disabled. Set to 1 to enable.
|
||
|
|
*
|
||
|
|
* Tells the decompressor that the ZSTD_outBuffer will ALWAYS be the same
|
||
|
|
* between calls, except for the modifications that zstd makes to pos (the
|
||
|
|
* caller must not modify pos). This is checked by the decompressor, and
|
||
|
|
* decompression will fail if it ever changes. Therefore the ZSTD_outBuffer
|
||
|
|
* MUST be large enough to fit the entire decompressed frame. This will be
|
||
|
|
* checked when the frame content size is known. The data in the ZSTD_outBuffer
|
||
|
|
* in the range [dst, dst + pos) MUST not be modified during decompression
|
||
|
|
* or you will get data corruption.
|
||
|
|
*
|
||
|
|
* When this flags is enabled zstd won't allocate an output buffer, because
|
||
|
|
* it can write directly to the ZSTD_outBuffer, but it will still allocate
|
||
|
|
* an input buffer large enough to fit any compressed block. This will also
|
||
|
|
* avoid the memcpy() from the internal output buffer to the ZSTD_outBuffer.
|
||
|
|
* If you need to avoid the input buffer allocation use the buffer-less
|
||
|
|
* streaming API.
|
||
|
|
*
|
||
|
|
* NOTE: So long as the ZSTD_outBuffer always points to valid memory, using
|
||
|
|
* this flag is ALWAYS memory safe, and will never access out-of-bounds
|
||
|
|
* memory. However, decompression WILL fail if you violate the preconditions.
|
||
|
|
*
|
||
|
|
* WARNING: The data in the ZSTD_outBuffer in the range [dst, dst + pos) MUST
|
||
|
|
* not be modified during decompression or you will get data corruption. This
|
||
|
|
* is because zstd needs to reference data in the ZSTD_outBuffer to regenerate
|
||
|
|
* matches. Normally zstd maintains its own buffer for this purpose, but passing
|
||
|
|
* this flag tells zstd to use the user provided buffer.
|
||
|
|
*/
|
||
|
|
#define ZSTD_d_stableOutBuffer ZSTD_d_experimentalParam2
|
||
|
|
|
||
|
|
/*! 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_decompressStream_simpleArgs() :
|
||
|
|
* Same as ZSTD_decompressStream(),
|
||
|
|
* but using only integral types as arguments.
|
||
|
|
* This can be helpful for binders from dynamic languages
|
||
|
|
* which have troubles handling structures containing memory pointers.
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API size_t ZSTD_decompressStream_simpleArgs (
|
||
|
|
ZSTD_DCtx* dctx,
|
||
|
|
void* dst, size_t dstCapacity, size_t* dstPos,
|
||
|
|
const void* src, size_t srcSize, size_t* srcPos);
|
||
|
|
|
||
|
|
|
||
|
|
/********************************************************************
|
||
|
|
* Advanced streaming functions
|
||
|
|
* Warning : most of these functions are now redundant with the Advanced API.
|
||
|
|
* Once Advanced API reaches "stable" status,
|
||
|
|
* redundant functions will be deprecated, and then at some point removed.
|
||
|
|
********************************************************************/
|
||
|
|
|
||
|
|
/*===== Advanced Streaming compression functions =====*/
|
||
|
|
/**! ZSTD_initCStream_srcSize() :
|
||
|
|
* This function is deprecated, and equivalent to:
|
||
|
|
* ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only);
|
||
|
|
* ZSTD_CCtx_refCDict(zcs, NULL); // clear the dictionary (if any)
|
||
|
|
* ZSTD_CCtx_setParameter(zcs, ZSTD_c_compressionLevel, compressionLevel);
|
||
|
|
* ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize);
|
||
|
|
*
|
||
|
|
* pledgedSrcSize must be correct. If it is not known at init time, use
|
||
|
|
* ZSTD_CONTENTSIZE_UNKNOWN. Note that, for compatibility with older programs,
|
||
|
|
* "0" also disables frame content size field. It may be enabled in the future.
|
||
|
|
* Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API size_t
|
||
|
|
ZSTD_initCStream_srcSize(ZSTD_CStream* zcs,
|
||
|
|
int compressionLevel,
|
||
|
|
unsigned long long pledgedSrcSize);
|
||
|
|
|
||
|
|
/**! ZSTD_initCStream_usingDict() :
|
||
|
|
* This function is deprecated, and is equivalent to:
|
||
|
|
* ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only);
|
||
|
|
* ZSTD_CCtx_setParameter(zcs, ZSTD_c_compressionLevel, compressionLevel);
|
||
|
|
* ZSTD_CCtx_loadDictionary(zcs, dict, dictSize);
|
||
|
|
*
|
||
|
|
* 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_dct_auto (treated as a full zstd dictionary if
|
||
|
|
* it begins with ZSTD_MAGIC_DICTIONARY, else as raw content) and ZSTD_dlm_byCopy.
|
||
|
|
* Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API size_t
|
||
|
|
ZSTD_initCStream_usingDict(ZSTD_CStream* zcs,
|
||
|
|
const void* dict, size_t dictSize,
|
||
|
|
int compressionLevel);
|
||
|
|
|
||
|
|
/**! ZSTD_initCStream_advanced() :
|
||
|
|
* This function is deprecated, and is approximately equivalent to:
|
||
|
|
* ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only);
|
||
|
|
* // Pseudocode: Set each zstd parameter and leave the rest as-is.
|
||
|
|
* for ((param, value) : params) {
|
||
|
|
* ZSTD_CCtx_setParameter(zcs, param, value);
|
||
|
|
* }
|
||
|
|
* ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize);
|
||
|
|
* ZSTD_CCtx_loadDictionary(zcs, dict, dictSize);
|
||
|
|
*
|
||
|
|
* dict is loaded with ZSTD_dct_auto and ZSTD_dlm_byCopy.
|
||
|
|
* pledgedSrcSize must be correct.
|
||
|
|
* If srcSize is not known at init time, use value ZSTD_CONTENTSIZE_UNKNOWN.
|
||
|
|
* Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API size_t
|
||
|
|
ZSTD_initCStream_advanced(ZSTD_CStream* zcs,
|
||
|
|
const void* dict, size_t dictSize,
|
||
|
|
ZSTD_parameters params,
|
||
|
|
unsigned long long pledgedSrcSize);
|
||
|
|
|
||
|
|
/**! ZSTD_initCStream_usingCDict() :
|
||
|
|
* This function is deprecated, and equivalent to:
|
||
|
|
* ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only);
|
||
|
|
* ZSTD_CCtx_refCDict(zcs, cdict);
|
||
|
|
*
|
||
|
|
* note : cdict will just be referenced, and must outlive compression session
|
||
|
|
* Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API size_t ZSTD_initCStream_usingCDict(ZSTD_CStream* zcs, const ZSTD_CDict* cdict);
|
||
|
|
|
||
|
|
/**! ZSTD_initCStream_usingCDict_advanced() :
|
||
|
|
* This function is DEPRECATED, and is approximately equivalent to:
|
||
|
|
* ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only);
|
||
|
|
* // Pseudocode: Set each zstd frame parameter and leave the rest as-is.
|
||
|
|
* for ((fParam, value) : fParams) {
|
||
|
|
* ZSTD_CCtx_setParameter(zcs, fParam, value);
|
||
|
|
* }
|
||
|
|
* ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize);
|
||
|
|
* ZSTD_CCtx_refCDict(zcs, cdict);
|
||
|
|
*
|
||
|
|
* same as ZSTD_initCStream_usingCDict(), with control over frame parameters.
|
||
|
|
* pledgedSrcSize must be correct. If srcSize is not known at init time, use
|
||
|
|
* value ZSTD_CONTENTSIZE_UNKNOWN.
|
||
|
|
* Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API size_t
|
||
|
|
ZSTD_initCStream_usingCDict_advanced(ZSTD_CStream* zcs,
|
||
|
|
const ZSTD_CDict* cdict,
|
||
|
|
ZSTD_frameParameters fParams,
|
||
|
|
unsigned long long pledgedSrcSize);
|
||
|
|
|
||
|
|
/*! ZSTD_resetCStream() :
|
||
|
|
* This function is deprecated, and is equivalent to:
|
||
|
|
* ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only);
|
||
|
|
* ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize);
|
||
|
|
*
|
||
|
|
* start a new frame, using same parameters from previous frame.
|
||
|
|
* This is typically useful to skip dictionary loading stage, since it will re-use it in-place.
|
||
|
|
* Note that zcs must be init at least once before using ZSTD_resetCStream().
|
||
|
|
* If pledgedSrcSize is not known at reset time, use macro ZSTD_CONTENTSIZE_UNKNOWN.
|
||
|
|
* If pledgedSrcSize > 0, its value must be correct, as it will be written in header, and controlled at the end.
|
||
|
|
* For the time being, pledgedSrcSize==0 is interpreted as "srcSize unknown" for compatibility with older programs,
|
||
|
|
* but it will change to mean "empty" in future version, so use macro ZSTD_CONTENTSIZE_UNKNOWN instead.
|
||
|
|
* @return : 0, or an error code (which can be tested using ZSTD_isError())
|
||
|
|
* Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API size_t ZSTD_resetCStream(ZSTD_CStream* zcs, unsigned long long pledgedSrcSize);
|
||
|
|
|
||
|
|
|
||
|
|
typedef struct {
|
||
|
|
unsigned long long ingested; /* nb input bytes read and buffered */
|
||
|
|
unsigned long long consumed; /* nb input bytes actually compressed */
|
||
|
|
unsigned long long produced; /* nb of compressed bytes generated and buffered */
|
||
|
|
unsigned long long flushed; /* nb of compressed bytes flushed : not provided; can be tracked from caller side */
|
||
|
|
unsigned currentJobID; /* MT only : latest started job nb */
|
||
|
|
unsigned nbActiveWorkers; /* MT only : nb of workers actively compressing at probe time */
|
||
|
|
} ZSTD_frameProgression;
|
||
|
|
|
||
|
|
/* ZSTD_getFrameProgression() :
|
||
|
|
* tells how much data has been ingested (read from input)
|
||
|
|
* consumed (input actually compressed) and produced (output) for current frame.
|
||
|
|
* Note : (ingested - consumed) is amount of input data buffered internally, not yet compressed.
|
||
|
|
* Aggregates progression inside active worker threads.
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API ZSTD_frameProgression ZSTD_getFrameProgression(const ZSTD_CCtx* cctx);
|
||
|
|
|
||
|
|
/*! ZSTD_toFlushNow() :
|
||
|
|
* Tell how many bytes are ready to be flushed immediately.
|
||
|
|
* Useful for multithreading scenarios (nbWorkers >= 1).
|
||
|
|
* Probe the oldest active job, defined as oldest job not yet entirely flushed,
|
||
|
|
* and check its output buffer.
|
||
|
|
* @return : amount of data stored in oldest job and ready to be flushed immediately.
|
||
|
|
* if @return == 0, it means either :
|
||
|
|
* + there is no active job (could be checked with ZSTD_frameProgression()), or
|
||
|
|
* + oldest job is still actively compressing data,
|
||
|
|
* but everything it has produced has also been flushed so far,
|
||
|
|
* therefore flush speed is limited by production speed of oldest job
|
||
|
|
* irrespective of the speed of concurrent (and newer) jobs.
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API size_t ZSTD_toFlushNow(ZSTD_CCtx* cctx);
|
||
|
|
|
||
|
|
|
||
|
|
/*===== Advanced Streaming decompression functions =====*/
|
||
|
|
/**
|
||
|
|
* This function is deprecated, and is equivalent to:
|
||
|
|
*
|
||
|
|
* ZSTD_DCtx_reset(zds, ZSTD_reset_session_only);
|
||
|
|
* ZSTD_DCtx_loadDictionary(zds, dict, dictSize);
|
||
|
|
*
|
||
|
|
* note: no dictionary will be used if dict == NULL or dictSize < 8
|
||
|
|
* Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API size_t ZSTD_initDStream_usingDict(ZSTD_DStream* zds, const void* dict, size_t dictSize);
|
||
|
|
|
||
|
|
/**
|
||
|
|
* This function is deprecated, and is equivalent to:
|
||
|
|
*
|
||
|
|
* ZSTD_DCtx_reset(zds, ZSTD_reset_session_only);
|
||
|
|
* ZSTD_DCtx_refDDict(zds, ddict);
|
||
|
|
*
|
||
|
|
* note : ddict is referenced, it must outlive decompression session
|
||
|
|
* Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API size_t ZSTD_initDStream_usingDDict(ZSTD_DStream* zds, const ZSTD_DDict* ddict);
|
||
|
|
|
||
|
|
/**
|
||
|
|
* This function is deprecated, and is equivalent to:
|
||
|
|
*
|
||
|
|
* ZSTD_DCtx_reset(zds, ZSTD_reset_session_only);
|
||
|
|
*
|
||
|
|
* re-use decompression parameters from previous init; saves dictionary loading
|
||
|
|
* Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x
|
||
|
|
*/
|
||
|
|
ZSTDLIB_API size_t ZSTD_resetDStream(ZSTD_DStream* zds);
|
||
|
|
|
||
|
|
|
||
|
|
/*********************************************************************
|
||
|
|
* Buffer-less and synchronous inner streaming functions
|
||
|
|
*
|
||
|
|
* This is an advanced API, giving full control over buffer management, for users which need direct control over memory.
|
||
|
|
* But it's also a complex one, with several restrictions, documented below.
|
||
|
|
* Prefer normal streaming API for an easier experience.
|
||
|
|
********************************************************************* */
|
||
|
|
|
||
|
|
/**
|
||
|
|
Buffer-less streaming compression (synchronous mode)
|
||
|
|
|
||
|
|
A ZSTD_CCtx object is required to track streaming operations.
|
||
|
|
Use ZSTD_createCCtx() / ZSTD_freeCCtx() to manage resource.
|
||
|
|
ZSTD_CCtx object can be re-used multiple times within successive compression operations.
|
||
|
|
|
||
|
|
Start by initializing a context.
|
||
|
|
Use ZSTD_compressBegin(), or ZSTD_compressBegin_usingDict() for dictionary compression,
|
||
|
|
or ZSTD_compressBegin_advanced(), for finer parameter control.
|
||
|
|
It's also possible to duplicate a reference context which has already been initialized, using ZSTD_copyCCtx()
|
||
|
|
|
||
|
|
Then, consume your input using ZSTD_compressContinue().
|
||
|
|
There are some important considerations to keep in mind when using this advanced function :
|
||
|
|
- ZSTD_compressContinue() has no internal buffer. It uses externally provided buffers only.
|
||
|
|
- Interface is synchronous : input is consumed entirely and produces 1+ compressed blocks.
|
||
|
|
- Caller must ensure there is enough space in `dst` to store compressed data under worst case scenario.
|
||
|
|
Worst case evaluation is provided by ZSTD_compressBound().
|
||
|
|
ZSTD_compressContinue() doesn't guarantee recover after a failed compression.
|
||
|
|
- ZSTD_compressContinue() presumes prior input ***is still accessible and unmodified*** (up to maximum distance size, see WindowLog).
|
||
|
|
It remembers all previous contiguous blocks, plus one separated memory segment (which can itself consists of multiple contiguous blocks)
|
||
|
|
- ZSTD_compressContinue() detects that prior input has been overwritten when `src` buffer overlaps.
|
||
|
|
In which case, it will "discard" the relevant memory section from its history.
|
||
|
|
|
||
|
|
Finish a frame with ZSTD_compressEnd(), which will write the last block(s) and optional checksum.
|
||
|
|
It's possible to use srcSize==0, in which case, it will write a final empty block to end the frame.
|
||
|
|
Without last block mark, frames are considered unfinished (hence corrupted) by compliant decoders.
|
||
|
|
|
||
|
|
`ZSTD_CCtx` object can be re-used (ZSTD_compressBegin()) to compress again.
|
||
|
|
*/
|
||
|
|
|
||
|
|
/*===== Buffer-less streaming compression functions =====*/
|
||
|
|
ZSTDLIB_API size_t ZSTD_compressBegin(ZSTD_CCtx* cctx, int compressionLevel);
|
||
|
|
ZSTDLIB_API size_t ZSTD_compressBegin_usingDict(ZSTD_CCtx* cctx, const void* dict, size_t dictSize, int compressionLevel);
|
||
|
|
ZSTDLIB_API size_t ZSTD_compressBegin_advanced(ZSTD_CCtx* cctx, const void* dict, size_t dictSize, ZSTD_parameters params, unsigned long long pledgedSrcSize); /**< pledgedSrcSize : If srcSize is not known at init time, use ZSTD_CONTENTSIZE_UNKNOWN */
|
||
|
|
ZSTDLIB_API size_t ZSTD_compressBegin_usingCDict(ZSTD_CCtx* cctx, const ZSTD_CDict* cdict); /**< note: fails if cdict==NULL */
|
||
|
|
ZSTDLIB_API size_t ZSTD_compressBegin_usingCDict_advanced(ZSTD_CCtx* const cctx, const ZSTD_CDict* const cdict, ZSTD_frameParameters const fParams, unsigned long long const pledgedSrcSize); /* compression parameters are already set within cdict. pledgedSrcSize must be correct. If srcSize is not known, use macro ZSTD_CONTENTSIZE_UNKNOWN */
|
||
|
|
ZSTDLIB_API size_t ZSTD_copyCCtx(ZSTD_CCtx* cctx, const ZSTD_CCtx* preparedCCtx, unsigned long long pledgedSrcSize); /**< note: if pledgedSrcSize is not known, use ZSTD_CONTENTSIZE_UNKNOWN */
|
||
|
|
|
||
|
|
ZSTDLIB_API size_t ZSTD_compressContinue(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);
|
||
|
|
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)
|
||
|
|
|
||
|
|
A ZSTD_DCtx object is required to track streaming operations.
|
||
|
|
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_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().
|
||
|
|
|
||
|
|
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 : it just means ZSTD_decompressContinue() has decoded some metadata item.
|
||
|
|
It can also be an error code, which can be tested with ZSTD_isError().
|
||
|
|
|
||
|
|
A frame is fully decoded when ZSTD_nextSrcSizeToDecompress() returns zero.
|
||
|
|
Context can then be reset to start a new decompression.
|
||
|
|
|
||
|
|
Note : it's possible to know if next input to present is a header or a block, using ZSTD_nextInputType().
|
||
|
|
This information is not required to properly decode a frame.
|
||
|
|
|
||
|
|
== 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 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_getFrameHeader() returns zfhPtr->frameType==ZSTD_skippableFrame.
|
||
|
|
For skippable frames ZSTD_decompressContinue() always returns 0 : it only skips the content.
|
||
|
|
*/
|
||
|
|
|
||
|
|
/*===== Buffer-less streaming decompression functions =====*/
|
||
|
|
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;
|
||
|
|
|
||
|
|
/*! ZSTD_getFrameHeader() :
|
||
|
|
* decode Frame Header, or requires larger `srcSize`.
|
||
|
|
* @return : 0, `zfhPtr` is correctly filled,
|
||
|
|
* >0, `srcSize` is too small, value is wanted `srcSize` amount,
|
||
|
|
* or an error code, which can be tested using ZSTD_isError() */
|
||
|
|
ZSTDLIB_API size_t ZSTD_getFrameHeader(ZSTD_frameHeader* zfhPtr, const void* src, size_t srcSize); /**< doesn't consume input */
|
||
|
|
/*! ZSTD_getFrameHeader_advanced() :
|
||
|
|
* same as ZSTD_getFrameHeader(),
|
||
|
|
* with added capability to select a format (like ZSTD_f_zstd1_magicless) */
|
||
|
|
ZSTDLIB_API size_t ZSTD_getFrameHeader_advanced(ZSTD_frameHeader* zfhPtr, const void* src, size_t srcSize, ZSTD_format_e format);
|
||
|
|
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 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);
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
/* ============================ */
|
||
|
|
/** Block level API */
|
||
|
|
/* ============================ */
|
||
|
|
|
||
|
|
/*!
|
||
|
|
Block functions produce and decode raw zstd blocks, without frame metadata.
|
||
|
|
Frame metadata cost is typically ~12 bytes, which can be non-negligible for very small blocks (< 100 bytes).
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But users will have to take in charge needed metadata to regenerate data, such as compressed and content sizes.
|
||
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|
||
|
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A few rules to respect :
|
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|
|
- Compressing and decompressing require a context structure
|
||
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+ Use ZSTD_createCCtx() and ZSTD_createDCtx()
|
||
|
|
- It is necessary to init context before starting
|
||
|
|
+ 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 == 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, consider using regular ZSTD_compress() instead.
|
||
|
|
Frame metadata is not that costly, and quickly becomes negligible as source size grows larger than a block.
|
||
|
|
- When a block is considered not compressible enough, ZSTD_compressBlock() result will be 0 (zero) !
|
||
|
|
===> In which case, nothing is produced into `dst` !
|
||
|
|
+ User __must__ test for such outcome and deal directly with uncompressed data
|
||
|
|
+ A block cannot be declared incompressible if ZSTD_compressBlock() return value was != 0.
|
||
|
|
Doing so would mess up with statistics history, leading to potential data corruption.
|
||
|
|
+ ZSTD_decompressBlock() _doesn't accept uncompressed data as input_ !!
|
||
|
|
+ In case of multiple successive blocks, should some of them be uncompressed,
|
||
|
|
decoder must be informed of their existence in order to follow proper history.
|
||
|
|
Use ZSTD_insertBlock() for such a case.
|
||
|
|
*/
|
||
|
|
|
||
|
|
/*===== Raw zstd block functions =====*/
|
||
|
|
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 uncompressed block into `dctx` history. Useful for multi-blocks decompression. */
|
||
|
|
|
||
|
|
|
||
|
|
#endif /* ZSTD_H_ZSTD_STATIC_LINKING_ONLY */
|
||
|
|
|
||
|
|
#if defined (__cplusplus)
|
||
|
|
}
|
||
|
|
#endif
|