lz4frame.h : clarified a few comments
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Yann Collet
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@ -1,7 +1,7 @@
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/*
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LZ4 auto-framing library
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Header File
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Copyright (C) 2011-2014, Yann Collet.
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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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@ -29,6 +29,7 @@
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You can contact the author at :
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- LZ4 source repository : http://code.google.com/p/lz4/
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- LZ4 source mirror : 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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@ -46,7 +47,7 @@ extern "C" {
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/****************************************
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Note : experimental API.
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Not yet integrated within lz4 library.
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Not yet integrated within liblz4
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****************************************/
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/**************************************
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@ -56,8 +57,8 @@ extern "C" {
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/**************************************
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Error management
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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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#define LZ4F_LIST_ERRORS(ITEM) \
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ITEM(OK_NoError) ITEM(ERROR_GENERIC) \
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@ -72,15 +73,15 @@ typedef size_t LZ4F_errorCode_t;
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#define LZ4F_GENERATE_ENUM(ENUM) ENUM,
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typedef enum { LZ4F_LIST_ERRORS(LZ4F_GENERATE_ENUM) } LZ4F_errorCodes; /* enum is exposed, to detect & handle specific errors; compare function result to -enum value */
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int LZ4F_isError(LZ4F_errorCode_t code); /* Basically : code > -ERROR_maxCode */
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const char* LZ4F_getErrorName(LZ4F_errorCode_t code); /* return enum as string */
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int LZ4F_isError(LZ4F_errorCode_t code); /* Basically : code > -ERROR_maxCode */
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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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Framing compression functions
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**************************************/
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* Frame compression types
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* ************************************/
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typedef enum { LZ4F_default=0, max64KB=4, max256KB=5, max1MB=6, max4MB=7} blockSizeID_t;
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typedef enum { LZ4F_default=0, max64KB=4, max256KB=5, max1MB=6, max4MB=7 } blockSizeID_t;
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typedef enum { blockLinked=0, blockIndependent} blockMode_t;
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typedef enum { noContentChecksum=0, contentChecksumEnabled } contentChecksum_t;
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@ -93,8 +94,8 @@ typedef struct {
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typedef struct {
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LZ4F_frameInfo_t frameInfo;
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unsigned compressionLevel; /* Not yet supported : only fast compression for the time being */
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unsigned autoFlush; /* 1 == always flush; reduce need for tmp buffer */
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unsigned compressionLevel; /* 0 == default (fast mode); values above 16 count as 16 */
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unsigned autoFlush; /* 1 == always flush : reduce need for tmp buffer */
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unsigned reserved[4];
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} LZ4F_preferences_t;
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@ -120,7 +121,7 @@ size_t LZ4F_compressFrame(void* dstBuffer, size_t dstMaxSize, const void* srcBuf
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/**********************************
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* Advanced compression functions
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* *********************************/
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* ********************************/
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typedef void* LZ4F_compressionContext_t;
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@ -159,6 +160,7 @@ size_t LZ4F_compressBound(size_t srcSize, const LZ4F_preferences_t* preferencesP
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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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* preferencesPtr is optional : you can provide NULL as argument, all preferences will then be set to default.
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* Note that different preferences will produce in different results.
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*/
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size_t LZ4F_compressUpdate(LZ4F_compressionContext_t compressionContext, void* dstBuffer, size_t dstMaxSize, const void* srcBuffer, size_t srcSize, const LZ4F_compressOptions_t* compressOptionsPtr);
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@ -207,19 +209,22 @@ typedef struct {
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/* Resource management */
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LZ4F_errorCode_t LZ4F_createDecompressionContext(LZ4F_compressionContext_t* LZ4F_decompressionContextPtr, unsigned version);
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LZ4F_errorCode_t LZ4F_freeDecompressionContext(LZ4F_compressionContext_t LZ4F_decompressionContext);
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LZ4F_errorCode_t LZ4F_createDecompressionContext(LZ4F_decompressionContext_t* ctxPtr, unsigned version);
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LZ4F_errorCode_t LZ4F_freeDecompressionContext(LZ4F_decompressionContext_t ctx);
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/* LZ4F_createDecompressionContext() :
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* The first thing to do is to create a decompressionContext object, which will be used in all decompression operations.
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* This is achieved using LZ4F_createDecompressionContext().
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* The function will provide a pointer to a fully allocated and initialized LZ4F_decompressionContext object.
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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 and initialized LZ4F_decompressionContext_t object.
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* If the result LZ4F_errorCode_t is not OK_NoError, there was an error during context creation.
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* Object can release its memory using LZ4F_freeDecompressionContext();
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*/
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/* Decompression */
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size_t LZ4F_getFrameInfo(LZ4F_decompressionContext_t decompressionContext, LZ4F_frameInfo_t* frameInfoPtr, const void* srcBuffer, size_t* srcSizePtr);
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size_t LZ4F_getFrameInfo(LZ4F_decompressionContext_t ctx,
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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 blockSize.
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* It is optional : you could start by calling directly LZ4F_decompress() instead.
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@ -231,7 +236,10 @@ size_t LZ4F_getFrameInfo(LZ4F_decompressionContext_t decompressionContext, LZ4F_
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* or an error code which can be tested using LZ4F_isError().
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*/
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size_t LZ4F_decompress(LZ4F_decompressionContext_t decompressionContext, void* dstBuffer, size_t* dstSizePtr, const void* srcBuffer, size_t* srcSizePtr, const LZ4F_decompressOptions_t* decompressOptionsPtr);
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size_t LZ4F_decompress(LZ4F_decompressionContext_t ctx,
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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* optionsPtr);
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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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@ -248,8 +256,8 @@ size_t LZ4F_decompress(LZ4F_decompressionContext_t decompressionContext, void* d
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*
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* The function result is an hint of the better srcSize to use for next call to LZ4F_decompress.
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* Basically, 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 allows less buffer shuffling.
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* Note that this is just a hint, you can always provide any srcSize you want.
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* Respecting the hint provides some boost to performance, since it does not need 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.
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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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