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224 lines
11 KiB
C
224 lines
11 KiB
C
/*
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LZ4 HC - High Compression Mode of LZ4
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Header File
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Copyright (C) 2011-2014, 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 homepage : http://fastcompression.blogspot.com/p/lz4.html
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- LZ4 source repository : http://code.google.com/p/lz4/
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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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int LZ4_compressHC (const char* source, char* dest, int inputSize);
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/*
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LZ4_compressHC :
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return : the number of bytes in compressed buffer dest
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or 0 if compression fails.
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note : destination buffer must be already allocated.
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To avoid any problem, size it to handle worst cases situations (input data not compressible)
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Worst case size evaluation is provided by function LZ4_compressBound() (see "lz4.h")
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*/
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int LZ4_compressHC_limitedOutput (const char* source, char* dest, int inputSize, int maxOutputSize);
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/*
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LZ4_compress_limitedOutput() :
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Compress 'inputSize' bytes from 'source' into an output buffer 'dest' of maximum size 'maxOutputSize'.
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If it cannot achieve it, compression will stop, and result of the function will be zero.
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This function never writes outside of provided output buffer.
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inputSize : Max supported value is 1 GB
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maxOutputSize : is maximum allowed size into the destination buffer (which must be already allocated)
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return : the number of output bytes written in buffer 'dest'
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or 0 if compression fails.
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*/
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int LZ4_compressHC2 (const char* source, char* dest, int inputSize, int compressionLevel);
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int LZ4_compressHC2_limitedOutput (const char* source, char* dest, int inputSize, int maxOutputSize, int compressionLevel);
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/*
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Same functions as above, but with programmable 'compressionLevel'.
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Recommended values are between 4 and 9, although any value between 0 and 16 will work.
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'compressionLevel'==0 means use default 'compressionLevel' value.
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Values above 16 behave the same as 16.
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Equivalent variants exist for all other compression functions below.
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*/
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/* Note :
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Decompression functions are provided within LZ4 source code (see "lz4.h") (BSD license)
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*/
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/**************************************
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Using an external allocation
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**************************************/
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int LZ4_sizeofStateHC(void);
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int LZ4_compressHC_withStateHC (void* state, const char* source, char* dest, int inputSize);
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int LZ4_compressHC_limitedOutput_withStateHC (void* state, const char* source, char* dest, int inputSize, int maxOutputSize);
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int LZ4_compressHC2_withStateHC (void* state, const char* source, char* dest, int inputSize, int compressionLevel);
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int LZ4_compressHC2_limitedOutput_withStateHC(void* state, const char* source, char* dest, int inputSize, int maxOutputSize, int compressionLevel);
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/*
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These functions are provided should you prefer to allocate memory for compression tables with your own allocation methods.
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To know how much memory must be allocated for the compression tables, use :
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int LZ4_sizeofStateHC();
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Note that tables must be aligned for pointer (32 or 64 bits), otherwise compression will fail (return code 0).
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The allocated memory can be provided to the compression functions using 'void* state' parameter.
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LZ4_compress_withStateHC() and LZ4_compress_limitedOutput_withStateHC() are equivalent to previously described functions.
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They just use the externally allocated memory for state instead of allocating their own (on stack, or on heap).
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*/
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/**************************************
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Experimental Streaming Functions
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**************************************/
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#define LZ4_STREAMHCSIZE_U32 65548
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#define LZ4_STREAMHCSIZE (LZ4_STREAMHCSIZE_U32 * sizeof(unsigned int))
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typedef struct { unsigned int table[LZ4_STREAMHCSIZE_U32]; } LZ4_streamHC_t;
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/*
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This structure allows static allocation of LZ4 HC streaming state.
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State must then be initialized using LZ4_resetStreamHC() before first use.
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If you prefer dynamic allocation, please refer to functions below.
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*/
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LZ4_streamHC_t* LZ4_createStreamHC(void);
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int LZ4_freeStreamHC (LZ4_streamHC_t* LZ4_streamHCPtr);
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/*
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These functions create and release memory for LZ4 HC streaming state.
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Newly created states are already initialized.
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Existing state space can be re-used anytime using LZ4_resetStreamHC().
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*/
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void LZ4_resetStreamHC (LZ4_streamHC_t* LZ4_streamHCPtr, int compressionLevel);
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int LZ4_loadDictHC (LZ4_streamHC_t* LZ4_streamHCPtr, const char* dictionary, int dictSize);
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int LZ4_compressHC_continue (LZ4_streamHC_t* LZ4_streamHCPtr, const char* source, char* dest, int inputSize);
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int LZ4_compressHC_limitedOutput_continue (LZ4_streamHC_t* LZ4_streamHCPtr, const char* source, char* dest, int inputSize, int maxOutputSize);
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int LZ4_saveDictHC (LZ4_streamHC_t* LZ4_streamHCPtr, char* safeBuffer, int maxDictSize);
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/*
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These functions compress data in successive blocks of any size, using previous blocks as dictionary.
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One key assumption is that each previous block will remain read-accessible while compressing next block.
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Before starting compression, state must be properly initialized, using LZ4_resetStreamHC().
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A first "fictional block" can then be designated as initial dictionary, using LZ4_loadDictHC() (Optional).
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Then, use LZ4_compressHC_continue() or LZ4_compressHC_limitedOutput_continue() to compress each successive block.
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They work like usual LZ4_compressHC() or LZ4_compressHC_limitedOutput(), but use previous memory blocks to improve compression.
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Previous memory blocks (including initial dictionary when present) must remain accessible and unmodified during compression.
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If, for any reason, previous data block can't be preserved in memory during next compression block,
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you must save it to a safer memory space,
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using LZ4_saveDictHC().
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*/
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/**************************************
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Deprecated Streaming Functions
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**************************************/
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/* Note : these streaming functions still follows the older model */
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void* LZ4_createHC (const char* inputBuffer);
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//int LZ4_compressHC_continue (void* LZ4HC_Data, const char* source, char* dest, int inputSize);
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//int LZ4_compressHC_limitedOutput_continue (void* LZ4HC_Data, const char* source, char* dest, int inputSize, int maxOutputSize);
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char* LZ4_slideInputBufferHC (void* LZ4HC_Data);
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int LZ4_freeHC (void* LZ4HC_Data);
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int LZ4_compressHC2_continue (void* LZ4HC_Data, const char* source, char* dest, int inputSize, int compressionLevel);
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int LZ4_compressHC2_limitedOutput_continue (void* LZ4HC_Data, const char* source, char* dest, int inputSize, int maxOutputSize, int compressionLevel);
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/*
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These functions allow the compression of dependent blocks, where each block benefits from prior 64 KB within preceding blocks.
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In order to achieve this, it is necessary to start creating the LZ4HC Data Structure, thanks to the function :
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void* LZ4_createHC (const char* inputBuffer);
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The result of the function is the (void*) pointer on the LZ4HC Data Structure.
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This pointer will be needed in all other functions.
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If the pointer returned is NULL, then the allocation has failed, and compression must be aborted.
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The only parameter 'const char* inputBuffer' must, obviously, point at the beginning of input buffer.
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The input buffer must be already allocated, and size at least 192KB.
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'inputBuffer' will also be the 'const char* source' of the first block.
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All blocks are expected to lay next to each other within the input buffer, starting from 'inputBuffer'.
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To compress each block, use either LZ4_compressHC_continue() or LZ4_compressHC_limitedOutput_continue().
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Their behavior are identical to LZ4_compressHC() or LZ4_compressHC_limitedOutput(),
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but require the LZ4HC Data Structure as their first argument, and check that each block starts right after the previous one.
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If next block does not begin immediately after the previous one, the compression will fail (return 0).
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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 :
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char* LZ4_slideInputBufferHC(void* LZ4HC_Data);
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must be performed. It will typically copy the latest 64KB of input at the beginning of input buffer.
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Note that, for this function to work properly, minimum size of an input buffer must be 192KB.
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==> The memory position where the next input data block must start is provided as the result of the function.
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Compression can then resume, using LZ4_compressHC_continue() or LZ4_compressHC_limitedOutput_continue(), as usual.
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When compression is completed, a call to LZ4_freeHC() will release the memory used by the LZ4HC Data Structure.
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*/
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int LZ4_sizeofStreamStateHC(void);
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int LZ4_resetStreamStateHC(void* state, const char* inputBuffer);
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/*
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These functions achieve the same result as :
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void* LZ4_createHC (const char* inputBuffer);
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They are provided here to allow the user program to allocate memory using its own routines.
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To know how much space must be allocated, use LZ4_sizeofStreamStateHC();
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Note also that space must be aligned for pointers (32 or 64 bits).
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Once space is allocated, you must initialize it using : LZ4_resetStreamStateHC(void* state, const char* inputBuffer);
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void* state is a pointer to the space allocated.
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It must be aligned for pointers (32 or 64 bits), and be large enough.
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The parameter 'const char* inputBuffer' must, obviously, point at the beginning of input buffer.
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The input buffer must be already allocated, and size at least 192KB.
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'inputBuffer' will also be the 'const char* source' of the first block.
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The same space can be re-used multiple times, just by initializing it each time with LZ4_resetStreamState().
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return value of LZ4_resetStreamStateHC() must be 0 is OK.
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Any other value means there was an error (typically, state is not aligned for pointers (32 or 64 bits)).
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*/
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#if defined (__cplusplus)
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}
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#endif
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