304 lines
15 KiB
C
304 lines
15 KiB
C
/*
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LZ4 auto-framing library
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Header File
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Copyright (C) 2011-2015, Yann Collet.
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BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
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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
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met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above
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copyright notice, this list of conditions and the following disclaimer
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in the documentation and/or other materials provided with the
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distribution.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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You can contact the author at :
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- LZ4 source repository : https://github.com/Cyan4973/lz4
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- LZ4 public forum : https://groups.google.com/forum/#!forum/lz4c
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*/
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/* LZ4F is a stand-alone API to create LZ4-compressed frames
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* conformant with specification v1.5.1.
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* All related operations, including memory management, are handled internally by the library.
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* You don't need lz4.h when using lz4frame.h.
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* */
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#pragma once
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#if defined (__cplusplus)
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extern "C" {
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#endif
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/**************************************
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* Includes
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**************************************/
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#include <stddef.h> /* size_t */
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/**************************************
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* Error management
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**************************************/
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typedef size_t LZ4F_errorCode_t;
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unsigned LZ4F_isError(LZ4F_errorCode_t code);
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const char* LZ4F_getErrorName(LZ4F_errorCode_t code); /* return error code string; useful for debugging */
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/**************************************
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* Frame compression types
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**************************************/
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//#define LZ4F_DISABLE_OBSOLETE_ENUMS
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#ifndef LZ4F_DISABLE_OBSOLETE_ENUMS
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# define LZ4F_OBSOLETE_ENUM(x) ,x
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#else
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# define LZ4F_OBSOLETE_ENUM(x)
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#endif
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typedef enum {
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LZ4F_default=0,
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LZ4F_max64KB=4,
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LZ4F_max256KB=5,
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LZ4F_max1MB=6,
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LZ4F_max4MB=7
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LZ4F_OBSOLETE_ENUM(max64KB = LZ4F_max64KB)
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LZ4F_OBSOLETE_ENUM(max256KB = LZ4F_max256KB)
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LZ4F_OBSOLETE_ENUM(max1MB = LZ4F_max1MB)
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LZ4F_OBSOLETE_ENUM(max4MB = LZ4F_max4MB)
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} LZ4F_blockSizeID_t;
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typedef enum {
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LZ4F_blockLinked=0,
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LZ4F_blockIndependent
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LZ4F_OBSOLETE_ENUM(blockLinked = LZ4F_blockLinked)
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LZ4F_OBSOLETE_ENUM(blockIndependent = LZ4F_blockIndependent)
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} LZ4F_blockMode_t;
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typedef enum {
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LZ4F_noContentChecksum=0,
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LZ4F_contentChecksumEnabled
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LZ4F_OBSOLETE_ENUM(noContentChecksum = LZ4F_noContentChecksum)
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LZ4F_OBSOLETE_ENUM(contentChecksumEnabled = LZ4F_contentChecksumEnabled)
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} LZ4F_contentChecksum_t;
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typedef enum {
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LZ4F_frame=0,
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LZ4F_skippableFrame
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LZ4F_OBSOLETE_ENUM(skippableFrame = LZ4F_skippableFrame)
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} LZ4F_frameType_t;
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#ifndef LZ4F_DISABLE_OBSOLETE_ENUMS
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typedef LZ4F_blockSizeID_t blockSizeID_t;
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typedef LZ4F_blockMode_t blockMode_t;
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typedef LZ4F_frameType_t frameType_t;
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typedef LZ4F_contentChecksum_t contentChecksum_t;
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#endif
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typedef struct {
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LZ4F_blockSizeID_t blockSizeID; /* max64KB, max256KB, max1MB, max4MB ; 0 == default */
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LZ4F_blockMode_t blockMode; /* blockLinked, blockIndependent ; 0 == default */
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LZ4F_contentChecksum_t contentChecksumFlag; /* noContentChecksum, contentChecksumEnabled ; 0 == default */
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LZ4F_frameType_t frameType; /* LZ4F_frame, skippableFrame ; 0 == default */
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unsigned long long contentSize; /* Size of uncompressed (original) content ; 0 == unknown */
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unsigned reserved[2]; /* must be zero for forward compatibility */
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} LZ4F_frameInfo_t;
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typedef struct {
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LZ4F_frameInfo_t frameInfo;
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int compressionLevel; /* 0 == default (fast mode); values above 16 count as 16; values below 0 count as 0 */
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unsigned autoFlush; /* 1 == always flush (reduce need for tmp buffer) */
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unsigned reserved[4]; /* must be zero for forward compatibility */
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} LZ4F_preferences_t;
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/***********************************
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* Simple compression function
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***********************************/
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size_t LZ4F_compressFrameBound(size_t srcSize, const LZ4F_preferences_t* preferencesPtr);
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size_t LZ4F_compressFrame(void* dstBuffer, size_t dstMaxSize, const void* srcBuffer, size_t srcSize, const LZ4F_preferences_t* preferencesPtr);
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/* LZ4F_compressFrame()
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* Compress an entire srcBuffer into a valid LZ4 frame, as defined by specification v1.5.1
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* The most important rule is that dstBuffer MUST be large enough (dstMaxSize) to ensure compression completion even in worst case.
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* You can get the minimum value of dstMaxSize by using LZ4F_compressFrameBound()
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* If this condition is not respected, LZ4F_compressFrame() will fail (result is an errorCode)
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* The LZ4F_preferences_t structure is optional : you can provide NULL as argument. All preferences will be set to default.
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* The result of the function is the number of bytes written into dstBuffer.
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* The function outputs an error code if it fails (can be tested using LZ4F_isError())
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*/
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/**********************************
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* Advanced compression functions
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**********************************/
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typedef struct LZ4F_cctx_s* LZ4F_compressionContext_t; /* must be aligned on 8-bytes */
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typedef struct {
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unsigned stableSrc; /* 1 == src content will remain available on future calls to LZ4F_compress(); avoid saving src content within tmp buffer as future dictionary */
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unsigned reserved[3];
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} LZ4F_compressOptions_t;
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/* Resource Management */
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#define LZ4F_VERSION 100
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LZ4F_errorCode_t LZ4F_createCompressionContext(LZ4F_compressionContext_t* cctxPtr, unsigned version);
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LZ4F_errorCode_t LZ4F_freeCompressionContext(LZ4F_compressionContext_t cctx);
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/* LZ4F_createCompressionContext() :
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* The first thing to do is to create a compressionContext object, which will be used in all compression operations.
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* This is achieved using LZ4F_createCompressionContext(), which takes as argument a version and an LZ4F_preferences_t structure.
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* The version provided MUST be LZ4F_VERSION. It is intended to track potential version differences between different binaries.
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* The function will provide a pointer to a fully allocated LZ4F_compressionContext_t object.
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* If the result LZ4F_errorCode_t is not zero, there was an error during context creation.
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* Object can release its memory using LZ4F_freeCompressionContext();
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*/
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/* Compression */
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size_t LZ4F_compressBegin(LZ4F_compressionContext_t cctx, void* dstBuffer, size_t dstMaxSize, const LZ4F_preferences_t* prefsPtr);
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/* LZ4F_compressBegin() :
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* will write the frame header into dstBuffer.
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* dstBuffer must be large enough to accommodate a header (dstMaxSize). Maximum header size is 15 bytes.
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* The LZ4F_preferences_t structure is optional : you can provide NULL as argument, all preferences will then be set to default.
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* The result of the function is the number of bytes written into dstBuffer for the header
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* or an error code (can be tested using LZ4F_isError())
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*/
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size_t LZ4F_compressBound(size_t srcSize, const LZ4F_preferences_t* prefsPtr);
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/* LZ4F_compressBound() :
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* Provides the minimum size of Dst buffer given srcSize to handle worst case situations.
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* Different preferences can produce different results.
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* prefsPtr is optional : you can provide NULL as argument, all preferences will then be set to cover worst case.
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* This function includes frame termination cost (4 bytes, or 8 if frame checksum is enabled)
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*/
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size_t LZ4F_compressUpdate(LZ4F_compressionContext_t cctx, void* dstBuffer, size_t dstMaxSize, const void* srcBuffer, size_t srcSize, const LZ4F_compressOptions_t* cOptPtr);
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/* LZ4F_compressUpdate()
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* LZ4F_compressUpdate() can be called repetitively to compress as much data as necessary.
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* The most important rule is that dstBuffer MUST be large enough (dstMaxSize) to ensure compression completion even in worst case.
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* You can get the minimum value of dstMaxSize by using LZ4F_compressBound().
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* If this condition is not respected, LZ4F_compress() will fail (result is an errorCode).
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* LZ4F_compressUpdate() doesn't guarantee error recovery, so you have to reset compression context when an error occurs.
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* The LZ4F_compressOptions_t structure is optional : you can provide NULL as argument.
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* The result of the function is the number of bytes written into dstBuffer : it can be zero, meaning input data was just buffered.
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* The function outputs an error code if it fails (can be tested using LZ4F_isError())
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*/
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size_t LZ4F_flush(LZ4F_compressionContext_t cctx, void* dstBuffer, size_t dstMaxSize, const LZ4F_compressOptions_t* cOptPtr);
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/* LZ4F_flush()
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* Should you need to generate compressed data immediately, without waiting for the current block to be filled,
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* you can call LZ4_flush(), which will immediately compress any remaining data buffered within cctx.
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* Note that dstMaxSize must be large enough to ensure the operation will be successful.
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* LZ4F_compressOptions_t structure is optional : you can provide NULL as argument.
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* The result of the function is the number of bytes written into dstBuffer
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* (it can be zero, this means there was no data left within cctx)
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* The function outputs an error code if it fails (can be tested using LZ4F_isError())
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*/
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size_t LZ4F_compressEnd(LZ4F_compressionContext_t cctx, void* dstBuffer, size_t dstMaxSize, const LZ4F_compressOptions_t* cOptPtr);
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/* LZ4F_compressEnd()
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* When you want to properly finish the compressed frame, just call LZ4F_compressEnd().
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* It will flush whatever data remained within compressionContext (like LZ4_flush())
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* but also properly finalize the frame, with an endMark and a checksum.
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* The result of the function is the number of bytes written into dstBuffer (necessarily >= 4 (endMark), or 8 if optional frame checksum is enabled)
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* The function outputs an error code if it fails (can be tested using LZ4F_isError())
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* The LZ4F_compressOptions_t structure is optional : you can provide NULL as argument.
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* A successful call to LZ4F_compressEnd() makes cctx available again for next compression task.
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*/
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/***********************************
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* Decompression functions
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***********************************/
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typedef struct LZ4F_dctx_s* LZ4F_decompressionContext_t; /* must be aligned on 8-bytes */
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typedef struct {
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unsigned stableDst; /* guarantee that decompressed data will still be there on next function calls (avoid storage into tmp buffers) */
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unsigned reserved[3];
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} LZ4F_decompressOptions_t;
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/* Resource management */
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LZ4F_errorCode_t LZ4F_createDecompressionContext(LZ4F_decompressionContext_t* dctxPtr, unsigned version);
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LZ4F_errorCode_t LZ4F_freeDecompressionContext(LZ4F_decompressionContext_t dctx);
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/* LZ4F_createDecompressionContext() :
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* The first thing to do is to create an LZ4F_decompressionContext_t object, which will be used in all decompression operations.
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* This is achieved using LZ4F_createDecompressionContext().
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* The version provided MUST be LZ4F_VERSION. It is intended to track potential breaking differences between different versions.
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* The function will provide a pointer to a fully allocated and initialized LZ4F_decompressionContext_t object.
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* The result is an errorCode, which can be tested using LZ4F_isError().
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* dctx memory can be released using LZ4F_freeDecompressionContext();
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* The result of LZ4F_freeDecompressionContext() is indicative of the current state of decompressionContext when being released.
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* That is, it should be == 0 if decompression has been completed fully and correctly.
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*/
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/* Decompression */
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size_t LZ4F_getFrameInfo(LZ4F_decompressionContext_t dctx,
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LZ4F_frameInfo_t* frameInfoPtr,
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const void* srcBuffer, size_t* srcSizePtr);
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/* LZ4F_getFrameInfo()
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* This function decodes frame header information (such as max blockSize, frame checksum, etc.).
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* Its usage is optional. The objective is to extract frame header information, typically for allocation purposes.
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* A header size is variable and can be from 7 to 15 bytes. It's also possible to input more bytes than that.
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* The number of bytes read from srcBuffer will be updated within *srcSizePtr (necessarily <= original value).
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* (note that LZ4F_getFrameInfo() can also be used anytime *after* starting decompression, in this case 0 input byte is enough)
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* Frame header info is *copied into* an already allocated LZ4F_frameInfo_t structure.
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* The function result is an hint about how many srcSize bytes LZ4F_decompress() expects for next call,
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* or an error code which can be tested using LZ4F_isError()
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* (typically, when there is not enough src bytes to fully decode the frame header)
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* Decompression is expected to resume from where it stopped (srcBuffer + *srcSizePtr)
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*/
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size_t LZ4F_decompress(LZ4F_decompressionContext_t dctx,
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void* dstBuffer, size_t* dstSizePtr,
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const void* srcBuffer, size_t* srcSizePtr,
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const LZ4F_decompressOptions_t* dOptPtr);
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/* LZ4F_decompress()
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* Call this function repetitively to regenerate data compressed within srcBuffer.
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* The function will attempt to decode *srcSizePtr bytes from srcBuffer, into dstBuffer of maximum size *dstSizePtr.
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*
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* The number of bytes regenerated into dstBuffer will be provided within *dstSizePtr (necessarily <= original value).
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*
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* The number of bytes read from srcBuffer will be provided within *srcSizePtr (necessarily <= original value).
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* If number of bytes read is < number of bytes provided, then decompression operation is not completed.
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* It typically happens when dstBuffer is not large enough to contain all decoded data.
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* LZ4F_decompress() must be called again, starting from where it stopped (srcBuffer + *srcSizePtr)
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* The function will check this condition, and refuse to continue if it is not respected.
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*
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* dstBuffer is supposed to be flushed between each call to the function, since its content will be overwritten.
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* dst arguments can be changed at will with each consecutive call to the function.
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*
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* The function result is an hint of how many srcSize bytes LZ4F_decompress() expects for next call.
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* Schematically, it's the size of the current (or remaining) compressed block + header of next block.
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* Respecting the hint provides some boost to performance, since it does skip intermediate buffers.
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* This is just a hint, you can always provide any srcSize you want.
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* When a frame is fully decoded, the function result will be 0 (no more data expected).
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* If decompression failed, function result is an error code, which can be tested using LZ4F_isError().
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*
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* After a frame is fully decoded, dctx can be used again to decompress another frame.
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*/
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#if defined (__cplusplus)
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}
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#endif
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