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zstd/lib/common/zstd.h

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/*
zstd - standard compression library
Header File
Copyright (C) 2014-2016, Yann Collet.
BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above
copyright notice, this list of conditions and the following disclaimer
in the documentation and/or other materials provided with the
distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
You can contact the author at :
- zstd source repository : https://github.com/Cyan4973/zstd
*/
#ifndef ZSTD_H_235446
#define ZSTD_H_235446
#if defined (__cplusplus)
extern "C" {
#endif
/*-*************************************
* Dependencies
***************************************/
#include <stddef.h> /* size_t */
/*-***************************************************************
* Export parameters
*****************************************************************/
/*!
* ZSTD_DLL_EXPORT :
* Enable exporting of functions when building a Windows DLL
*/
#if defined(_WIN32) && defined(ZSTD_DLL_EXPORT) && (ZSTD_DLL_EXPORT==1)
# define ZSTDLIB_API __declspec(dllexport)
#else
# define ZSTDLIB_API
#endif
/* *************************************
* Version
***************************************/
#define ZSTD_VERSION_MAJOR 0
#define ZSTD_VERSION_MINOR 7
#define ZSTD_VERSION_RELEASE 0
#define ZSTD_LIB_VERSION ZSTD_VERSION_MAJOR.ZSTD_VERSION_MINOR.ZSTD_VERSION_RELEASE
#define ZSTD_QUOTE(str) #str
#define ZSTD_EXPAND_AND_QUOTE(str) ZSTD_QUOTE(str)
#define ZSTD_VERSION_STRING ZSTD_EXPAND_AND_QUOTE(ZSTD_LIB_VERSION)
#define ZSTD_VERSION_NUMBER (ZSTD_VERSION_MAJOR *100*100 + ZSTD_VERSION_MINOR *100 + ZSTD_VERSION_RELEASE)
ZSTDLIB_API unsigned ZSTD_versionNumber (void);
/* *************************************
* Simple functions
***************************************/
/*! ZSTD_compress() :
Compresses `srcSize` bytes from buffer `src` into buffer `dst` of size `dstCapacity`.
Destination buffer must be already allocated.
Compression runs faster if `dstCapacity` >= `ZSTD_compressBound(srcSize)`.
@return : the number of bytes written into `dst`,
or an error code if it fails (which can be tested using ZSTD_isError()) */
ZSTDLIB_API size_t ZSTD_compress( void* dst, size_t dstCapacity,
const void* src, size_t srcSize,
int compressionLevel);
/*! ZSTD_decompress() :
`compressedSize` : is the _exact_ size of the compressed blob, otherwise decompression will fail.
`dstCapacity` must be large enough, equal or larger than originalSize.
@return : the number of bytes decompressed into `dst` (<= `dstCapacity`),
or an errorCode if it fails (which can be tested using ZSTD_isError()) */
ZSTDLIB_API size_t ZSTD_decompress( void* dst, size_t dstCapacity,
const void* src, size_t compressedSize);
/* *************************************
* Helper functions
***************************************/
ZSTDLIB_API size_t ZSTD_compressBound(size_t srcSize); /*!< maximum compressed size (worst case scenario) */
/* Error Management */
ZSTDLIB_API unsigned ZSTD_isError(size_t code); /*!< tells if a `size_t` function result is an error code */
ZSTDLIB_API const char* ZSTD_getErrorName(size_t code); /*!< provides readable string for an error code */
/* *************************************
* Explicit memory management
***************************************/
/** Compression context */
typedef struct ZSTD_CCtx_s ZSTD_CCtx; /*< incomplete type */
ZSTDLIB_API ZSTD_CCtx* ZSTD_createCCtx(void);
ZSTDLIB_API size_t ZSTD_freeCCtx(ZSTD_CCtx* cctx); /*!< @return : errorCode */
/** ZSTD_compressCCtx() :
Same as ZSTD_compress(), but requires an already allocated ZSTD_CCtx (see ZSTD_createCCtx()) */
ZSTDLIB_API size_t ZSTD_compressCCtx(ZSTD_CCtx* ctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize, int compressionLevel);
/** Decompression context */
typedef struct ZSTD_DCtx_s ZSTD_DCtx;
ZSTDLIB_API ZSTD_DCtx* ZSTD_createDCtx(void);
ZSTDLIB_API size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx); /*!< @return : errorCode */
/** ZSTD_decompressDCtx() :
* Same as ZSTD_decompress(), but requires an already allocated ZSTD_DCtx (see ZSTD_createDCtx()) */
ZSTDLIB_API size_t ZSTD_decompressDCtx(ZSTD_DCtx* ctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);
/*-***********************
* Dictionary API
*************************/
/*! ZSTD_compress_usingDict() :
* Compression using a pre-defined Dictionary content (see dictBuilder).
* Note : dict can be NULL, in which case, it's equivalent to ZSTD_compressCCtx() */
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 pre-defined Dictionary content (see dictBuilder).
* Dictionary must be identical to the one used during compression, otherwise regenerated data will be corrupted.
* Note : dict can be NULL, in which case, it's equivalent to ZSTD_decompressDCtx() */
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);
#ifdef ZSTD_STATIC_LINKING_ONLY
/* ====================================================================================
* The definitions in this section are considered experimental.
* They should never be used in association with a dynamic library, as they may change in the future.
* They are provided for advanced usages.
* Use them only in association with static linking.
* ==================================================================================== */
/*--- Dependency ---*/
#include "mem.h"
/*--- Constants ---*/
#define ZSTD_MAGICNUMBER 0xFD2FB527 /* v0.7 */
#define ZSTD_MAGIC_SKIPPABLE_START 0x184D2A50U
#define ZSTD_WINDOWLOG_MAX ((U32)(MEM_32bits() ? 25 : 27))
#define ZSTD_WINDOWLOG_MIN 18
#define ZSTD_CHAINLOG_MAX (ZSTD_WINDOWLOG_MAX+1)
#define ZSTD_CHAINLOG_MIN 4
#define ZSTD_HASHLOG_MAX ZSTD_WINDOWLOG_MAX
#define ZSTD_HASHLOG_MIN 12
#define ZSTD_HASHLOG3_MAX 17
#define ZSTD_HASHLOG3_MIN 15
#define ZSTD_SEARCHLOG_MAX (ZSTD_WINDOWLOG_MAX-1)
#define ZSTD_SEARCHLOG_MIN 1
#define ZSTD_SEARCHLENGTH_MAX 7
#define ZSTD_SEARCHLENGTH_MIN 3
#define ZSTD_TARGETLENGTH_MIN 4
#define ZSTD_TARGETLENGTH_MAX 999
/*--- Types ---*/
typedef enum { ZSTD_fast, ZSTD_greedy, ZSTD_lazy, ZSTD_lazy2, ZSTD_btlazy2, ZSTD_btopt } ZSTD_strategy; /* from faster to stronger */
typedef struct {
U32 windowLog; /* largest match distance : larger == more compression, more memory needed during decompression */
U32 chainLog; /* fully searched segment : larger == more compression, slower, more memory (useless for fast) */
U32 hashLog; /* dispatch table : larger == faster, more memory */
U32 searchLog; /* nb of searches : larger == more compression, slower */
U32 searchLength; /* match length searched : larger == faster decompression, sometimes less compression */
U32 targetLength; /* acceptable match size for optimal parser (only) : larger == more compression, slower */
ZSTD_strategy strategy;
} ZSTD_compressionParameters;
typedef struct {
U32 contentSizeFlag; /* 1: content size will be in frame header (if known). */
U32 checksumFlag; /* 1: will generate a 22-bits checksum at end of frame, to be used for error detection by decompressor */
U32 noDictIDFlag; /* 1: no dict ID will be saved into frame header (if dictionary compression) */
} ZSTD_frameParameters;
typedef struct {
ZSTD_compressionParameters cParams;
ZSTD_frameParameters fParams;
} ZSTD_parameters;
/* custom memory allocation functions */
typedef void* (*ZSTD_allocFunction) (void* opaque, size_t size);
typedef void (*ZSTD_freeFunction) (void* opaque, void* address);
typedef struct { ZSTD_allocFunction customAlloc; ZSTD_freeFunction customFree; void* opaque; } ZSTD_customMem;
/*-*************************************
* Advanced functions
***************************************/
/*! ZSTD_createCCtx_advanced() :
* Create a ZSTD compression context using external alloc and free functions */
ZSTDLIB_API ZSTD_CCtx* ZSTD_createCCtx_advanced(ZSTD_customMem customMem);
/*! ZSTD_createDCtx_advanced() :
* Create a ZSTD decompression context using external alloc and free functions */
ZSTDLIB_API ZSTD_DCtx* ZSTD_createDCtx_advanced(ZSTD_customMem customMem);
ZSTDLIB_API unsigned ZSTD_maxCLevel (void);
/*! ZSTD_getCParams() :
* @return ZSTD_compressionParameters structure for a selected compression level and srcSize.
* `srcSize` value is optional, select 0 if not known */
ZSTDLIB_API ZSTD_compressionParameters ZSTD_getCParams(int compressionLevel, U64 srcSize, size_t dictSize);
/*! ZSTD_checkParams() :
* Ensure param values remain within authorized range */
ZSTDLIB_API size_t ZSTD_checkCParams(ZSTD_compressionParameters params);
/*! ZSTD_adjustParams() :
* optimize params for a given `srcSize` and `dictSize`.
* both values are optional, select `0` if unknown. */
ZSTDLIB_API ZSTD_compressionParameters ZSTD_adjustCParams(ZSTD_compressionParameters cPar, U64 srcSize, size_t dictSize);
/*! ZSTD_compress_advanced() :
* Same as ZSTD_compress_usingDict(), with fine-tune control of each compression parameter */
ZSTDLIB_API size_t ZSTD_compress_advanced (ZSTD_CCtx* ctx,
void* dst, size_t dstCapacity,
const void* src, size_t srcSize,
const void* dict,size_t dictSize,
ZSTD_parameters params);
/*! ZSTD_compress_usingPreparedDCtx() :
* Same as ZSTD_compress_usingDict, but using a reference context `preparedCCtx`, where dictionary has been loaded.
* It avoids reloading the dictionary each time.
* `preparedCCtx` must have been properly initialized using ZSTD_compressBegin_usingDict() or ZSTD_compressBegin_advanced().
* Requires 2 contexts : 1 for reference (preparedCCtx) which will not be modified, and 1 to run the compression operation (cctx) */
ZSTDLIB_API size_t ZSTD_compress_usingPreparedCCtx(
ZSTD_CCtx* cctx, const ZSTD_CCtx* preparedCCtx,
void* dst, size_t dstCapacity,
const void* src, size_t srcSize);
/*- Advanced Decompression functions -*/
/*! ZSTD_decompress_usingPreparedDCtx() :
* Same as ZSTD_decompress_usingDict, but using a reference context `preparedDCtx`, where dictionary has been loaded.
* It avoids reloading the dictionary each time.
* `preparedDCtx` must have been properly initialized using ZSTD_decompressBegin_usingDict().
* Requires 2 contexts : 1 for reference (preparedDCtx), which will not be modified, and 1 to run the decompression operation (dctx) */
ZSTDLIB_API size_t ZSTD_decompress_usingPreparedDCtx(
ZSTD_DCtx* dctx, const ZSTD_DCtx* preparedDCtx,
void* dst, size_t dstCapacity,
const void* src, size_t srcSize);
/* **************************************
* Streaming functions (direct mode)
****************************************/
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, U64 pledgedSrcSize);
ZSTDLIB_API size_t ZSTD_copyCCtx(ZSTD_CCtx* cctx, const ZSTD_CCtx* preparedCCtx);
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);
/*
Streaming compression, synchronous mode (bufferless)
A ZSTD_CCtx object is required to track streaming operations.
Use ZSTD_createCCtx() / ZSTD_freeCCtx() to manage it.
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().
The interface is synchronous, so all input will be consumed and produce a compressed output.
You must ensure there is enough space in destination buffer to store compressed data under worst case scenario.
Worst case evaluation is provided by ZSTD_compressBound().
Finish a frame with ZSTD_compressEnd(), which will write the epilogue.
Without the epilogue, frames will be considered incomplete by decoder.
You can then reuse ZSTD_CCtx to compress some new frame.
*/
typedef struct {
U64 frameContentSize;
U32 windowLog;
U32 dictID;
U32 checksumFlag;
} ZSTD_frameParams;
#define ZSTD_FRAMEHEADERSIZE_MAX 18 /* for static allocation */
static const size_t ZSTD_frameHeaderSize_min = 6;
static const size_t ZSTD_frameHeaderSize_max = ZSTD_FRAMEHEADERSIZE_MAX;
static const size_t ZSTD_skippableHeaderSize = 8; /* magic number + skippable frame length */
ZSTDLIB_API size_t ZSTD_getFrameParams(ZSTD_frameParams* fparamsPtr, const void* src, size_t srcSize); /**< doesn't consume input */
ZSTDLIB_API size_t ZSTD_decompressBegin(ZSTD_DCtx* dctx);
ZSTDLIB_API size_t ZSTD_decompressBegin_usingDict(ZSTD_DCtx* dctx, const void* dict, size_t dictSize);
ZSTDLIB_API void ZSTD_copyDCtx(ZSTD_DCtx* dctx, const ZSTD_DCtx* preparedDCtx);
ZSTDLIB_API size_t ZSTD_nextSrcSizeToDecompress(ZSTD_DCtx* dctx);
ZSTDLIB_API size_t ZSTD_decompressContinue(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);
/*
Streaming decompression, direct mode (bufferless)
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 optional operation is to retrieve frame parameters, using ZSTD_getFrameParams(), which doesn't consume the input.
It can provide the minimum size of rolling buffer required to properly decompress data,
and optionally the final size of uncompressed content.
(Note : content size is an optional info that may not be present. 0 means : content size unknown)
Frame parameters are extracted from the beginning of compressed frame.
The amount of data to read is variable, from ZSTD_frameHeaderSize_min to ZSTD_frameHeaderSize_max (so if `srcSize` >= ZSTD_frameHeaderSize_max, it will always work)
If `srcSize` is too small for operation to succeed, function will return the minimum size it requires to produce a result.
Result : 0 when successful, it means the ZSTD_frameParams structure has been filled.
>0 : means there is not enough data into `src`. Provides the expected size to successfully decode header.
errorCode, which can be tested using ZSTD_isError()
Start decompression, with ZSTD_decompressBegin() or ZSTD_decompressBegin_usingDict().
Alternatively, you can copy a prepared context, using ZSTD_copyDCtx().
Then use ZSTD_nextSrcSizeToDecompress() and ZSTD_decompressContinue() alternatively.
ZSTD_nextSrcSizeToDecompress() tells how much bytes to provide as 'srcSize' to ZSTD_decompressContinue().
ZSTD_decompressContinue() requires this exact amount of bytes, or it will fail.
ZSTD_decompressContinue() needs previous data blocks during decompression, up to (1 << windowlog).
They should preferably be located contiguously, prior to current block. Alternatively, a round buffer is also possible.
@result of ZSTD_decompressContinue() is the number of bytes regenerated within 'dst' (necessarily <= dstCapacity).
It can be zero, which is not an error; it just means ZSTD_decompressContinue() has decoded some header.
A frame is fully decoded when ZSTD_nextSrcSizeToDecompress() returns zero.
Context can then be reset to start a new decompression.
Skippable frames allow the integration of user-defined data into a flow of concatenated frames.
Skippable frames will be ignored (skipped) by a decompressor. The format of skippable frame is following:
a) Skippable frame ID - 4 Bytes, Little endian format, any value from 0x184D2A50 to 0x184D2A5F
b) Frame Size - 4 Bytes, Little endian format, unsigned 32-bits
c) Frame Content - any content (User Data) of length equal to Frame Size
For skippable frames ZSTD_decompressContinue() always returns 0.
For skippable frames ZSTD_getFrameParams() returns fparamsPtr->windowLog==0 what means that a frame is skippable.
It also returns Frame Size as fparamsPtr->frameContentSize.
*/
/* **************************************
* Block functions
****************************************/
/*! Block functions produce and decode raw zstd blocks, without frame metadata.
User will have to take in charge required information to regenerate data, such as compressed and content sizes.
A few rules to respect :
- Uncompressed block size must be <= ZSTD_BLOCKSIZE_MAX (128 KB)
- Compressing or decompressing requires a context structure
+ Use ZSTD_createCCtx() and ZSTD_createDCtx()
- It is necessary to init context before starting
+ compression : ZSTD_compressBegin()
+ decompression : ZSTD_decompressBegin()
+ variants _usingDict() are also allowed
+ copyCCtx() and copyDCtx() work too
- When a block is considered not compressible enough, ZSTD_compressBlock() result will be zero.
In which case, nothing is produced into `dst`.
+ User must test for such outcome and deal directly with uncompressed data
+ ZSTD_decompressBlock() doesn't accept uncompressed data as input !!
*/
#define ZSTD_BLOCKSIZE_MAX (128 * 1024) /* define, for static allocation */
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);
/*-*************************************
* Error management
***************************************/
#include "error_public.h"
/*! ZSTD_getErrorCode() :
convert a `size_t` function result into a `ZSTD_ErrorCode` enum type,
which can be used to compare directly with enum list published into "error_public.h" */
ZSTDLIB_API ZSTD_ErrorCode ZSTD_getErrorCode(size_t functionResult);
ZSTDLIB_API const char* ZSTD_getErrorString(ZSTD_ErrorCode code);
#endif /* ZSTD_STATIC_LINKING_ONLY */
#if defined (__cplusplus)
}
#endif
#endif /* ZSTD_H_235446 */
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