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lz4hc.h
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/*
LZ4 HC - High Compression Mode of LZ4
Header File
Copyright (C) 2011-2014, 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 :
- LZ4 homepage : http://fastcompression.blogspot.com/p/lz4.html
- LZ4 source repository : http://code.google.com/p/lz4/
*/
#ifndef _LZ4HC_H
#define _LZ4HC_H
#if defined (__cplusplus)
extern "C"
{
#endif
__declspec(dllexport) int LZ4_compressHC (const char* source, char* dest, int inputSize);
/*
LZ4_compressHC :
return : the number of bytes in compressed buffer dest
or 0 if compression fails.
note : destination buffer must be already allocated.
To avoid any problem, size it to handle worst cases situations (input data not compressible)
Worst case size evaluation is provided by function LZ4_compressBound() (see "lz4.h")
*/
__declspec(dllexport) int LZ4_compressHC_limitedOutput (const char* source, char* dest, int inputSize, int maxOutputSize);
/*
LZ4_compress_limitedOutput() :
Compress 'inputSize' bytes from 'source' into an output buffer 'dest' of maximum size 'maxOutputSize'.
If it cannot achieve it, compression will stop, and result of the function will be zero.
This function never writes outside of provided output buffer.
inputSize : Max supported value is 1 GB
maxOutputSize : is maximum allowed size into the destination buffer (which must be already allocated)
return : the number of output bytes written in buffer 'dest'
or 0 if compression fails.
*/
__declspec(dllexport) int LZ4_compressHC2 (const char* source, char* dest, int inputSize, int compressionLevel);
__declspec(dllexport) int LZ4_compressHC2_limitedOutput (const char* source, char* dest, int inputSize, int maxOutputSize, int compressionLevel);
/*
Same functions as above, but with programmable 'compressionLevel'.
Recommended values are between 4 and 9, although any value between 0 and 16 will work.
'compressionLevel'==0 means use default 'compressionLevel' value.
Values above 16 behave the same as 16.
Equivalent variants exist for all other compression functions below.
*/
/* Note :
Decompression functions are provided within LZ4 source code (see "lz4.h") (BSD license)
*/
/**************************************
Using an external allocation
**************************************/
__declspec(dllexport) int LZ4_sizeofStateHC(void);
__declspec(dllexport) int LZ4_compressHC_withStateHC (void* state, const char* source, char* dest, int inputSize);
__declspec(dllexport) int LZ4_compressHC_limitedOutput_withStateHC (void* state, const char* source, char* dest, int inputSize, int maxOutputSize);
__declspec(dllexport) int LZ4_compressHC2_withStateHC (void* state, const char* source, char* dest, int inputSize, int compressionLevel);
__declspec(dllexport) int LZ4_compressHC2_limitedOutput_withStateHC(void* state, const char* source, char* dest, int inputSize, int maxOutputSize, int compressionLevel);
/*
These functions are provided should you prefer to allocate memory for compression tables with your own allocation methods.
To know how much memory must be allocated for the compression tables, use :
int LZ4_sizeofStateHC();
Note that tables must be aligned for pointer (32 or 64 bits), otherwise compression will fail (return code 0).
The allocated memory can be provided to the compressions functions using 'void* state' parameter.
LZ4_compress_withStateHC() and LZ4_compress_limitedOutput_withStateHC() are equivalent to previously described functions.
They just use the externally allocated memory area instead of allocating their own (on stack, or on heap).
*/
/**************************************
Streaming Functions
**************************************/
__declspec(dllexport) void* LZ4_createHC (const char* inputBuffer);
__declspec(dllexport) int LZ4_compressHC_continue (void* LZ4HC_Data, const char* source, char* dest, int inputSize);
__declspec(dllexport) int LZ4_compressHC_limitedOutput_continue (void* LZ4HC_Data, const char* source, char* dest, int inputSize, int maxOutputSize);
__declspec(dllexport) char* LZ4_slideInputBufferHC (void* LZ4HC_Data);
__declspec(dllexport) int LZ4_freeHC (void* LZ4HC_Data);
__declspec(dllexport) int LZ4_compressHC2_continue (void* LZ4HC_Data, const char* source, char* dest, int inputSize, int compressionLevel);
__declspec(dllexport) int LZ4_compressHC2_limitedOutput_continue (void* LZ4HC_Data, const char* source, char* dest, int inputSize, int maxOutputSize, int compressionLevel);
/*
These functions allow the compression of dependent blocks, where each block benefits from prior 64 KB within preceding blocks.
In order to achieve this, it is necessary to start creating the LZ4HC Data Structure, thanks to the function :
void* LZ4_createHC (const char* inputBuffer);
The result of the function is the (void*) pointer on the LZ4HC Data Structure.
This pointer will be needed in all other functions.
If the pointer returned is NULL, then the allocation has failed, and compression must be aborted.
The only parameter 'const char* inputBuffer' must, obviously, point at the beginning of input buffer.
The input buffer must be already allocated, and size at least 192KB.
'inputBuffer' will also be the 'const char* source' of the first block.
All blocks are expected to lay next to each other within the input buffer, starting from 'inputBuffer'.
To compress each block, use either LZ4_compressHC_continue() or LZ4_compressHC_limitedOutput_continue().
Their behavior are identical to LZ4_compressHC() or LZ4_compressHC_limitedOutput(),
but require the LZ4HC Data Structure as their first argument, and check that each block starts right after the previous one.
If next block does not begin immediately after the previous one, the compression will fail (return 0).
When it's no longer possible to lay the next block after the previous one (not enough space left into input buffer), a call to :
char* LZ4_slideInputBufferHC(void* LZ4HC_Data);
must be performed. It will typically copy the latest 64KB of input at the beginning of input buffer.
Note that, for this function to work properly, minimum size of an input buffer must be 192KB.
==> The memory position where the next input data block must start is provided as the result of the function.
Compression can then resume, using LZ4_compressHC_continue() or LZ4_compressHC_limitedOutput_continue(), as usual.
When compression is completed, a call to LZ4_freeHC() will release the memory used by the LZ4HC Data Structure.
*/
__declspec(dllexport) int LZ4_sizeofStreamStateHC(void);
__declspec(dllexport) int LZ4_resetStreamStateHC(void* state, const char* inputBuffer);
/*
These functions achieve the same result as :
void* LZ4_createHC (const char* inputBuffer);
They are provided here to allow the user program to allocate memory using its own routines.
To know how much space must be allocated, use LZ4_sizeofStreamStateHC();
Note also that space must be aligned for pointers (32 or 64 bits).
Once space is allocated, you must initialize it using : LZ4_resetStreamStateHC(void* state, const char* inputBuffer);
void* state is a pointer to the space allocated.
It must be aligned for pointers (32 or 64 bits), and be large enough.
The parameter 'const char* inputBuffer' must, obviously, point at the beginning of input buffer.
The input buffer must be already allocated, and size at least 192KB.
'inputBuffer' will also be the 'const char* source' of the first block.
The same space can be re-used multiple times, just by initializing it each time with LZ4_resetStreamState().
return value of LZ4_resetStreamStateHC() must be 0 is OK.
Any other value means there was an error (typically, state is not aligned for pointers (32 or 64 bits)).
*/
#if defined (__cplusplus)
}
#endif
#endif //_LZ4HC_H