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252 lines
12 KiB
C
252 lines
12 KiB
C
/*
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LZ4 - Fast LZ compression algorithm
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Header File
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Copyright (C) 2011-2013, 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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/**************************************
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Version
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**************************************/
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#define LZ4_VERSION_MAJOR 1 /* for major interface/format changes */
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#define LZ4_VERSION_MINOR 1 /* for minor interface/format changes */
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#define LZ4_VERSION_RELEASE 3 /* for tweaks, bug-fixes, or development */
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/**************************************
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Compiler Options
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**************************************/
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#if (defined(__GNUC__) && defined(__STRICT_ANSI__)) || (defined(_MSC_VER) && !defined(__cplusplus)) /* Visual Studio */
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# define inline __inline /* Visual C is not C99, but supports some kind of inline */
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#endif
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/**************************************
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Simple Functions
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**************************************/
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int LZ4_compress (const char* source, char* dest, int inputSize);
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int LZ4_decompress_safe (const char* source, char* dest, int inputSize, int maxOutputSize);
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/*
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LZ4_compress() :
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Compresses 'inputSize' bytes from 'source' into 'dest'.
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Destination buffer must be already allocated,
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and must be sized to handle worst cases situations (input data not compressible)
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Worst case size evaluation is provided by function LZ4_compressBound()
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inputSize : Max supported value is LZ4_MAX_INPUT_VALUE
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return : the number of bytes written in buffer dest
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or 0 if the compression fails
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LZ4_decompress_safe() :
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maxOutputSize : is the size of the destination buffer (which must be already allocated)
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return : the number of bytes decoded in the destination buffer (necessarily <= maxOutputSize)
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If the source stream is detected malformed, the function will stop decoding and return a negative result.
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This function is protected against buffer overflow exploits (never writes outside of output buffer, and never reads outside of input buffer). Therefore, it is protected against malicious data packets
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*/
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/**************************************
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Advanced Functions
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**************************************/
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#define LZ4_MAX_INPUT_SIZE 0x7E000000 /* 2 113 929 216 bytes */
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#define LZ4_COMPRESSBOUND(isize) ((unsigned int)(isize) > (unsigned int)LZ4_MAX_INPUT_SIZE ? 0 : (isize) + ((isize)/255) + 16)
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static inline int LZ4_compressBound(int isize) { return LZ4_COMPRESSBOUND(isize); }
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/*
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LZ4_compressBound() :
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Provides the maximum size that LZ4 may output in a "worst case" scenario (input data not compressible)
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primarily useful for memory allocation of output buffer.
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inline function is recommended for the general case,
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macro is also provided when result needs to be evaluated at compilation (such as stack memory allocation).
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isize : is the input size. Max supported value is LZ4_MAX_INPUT_SIZE
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return : maximum output size in a "worst case" scenario
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or 0, if input size is too large ( > LZ4_MAX_INPUT_SIZE)
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*/
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int LZ4_compress_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 LZ4_MAX_INPUT_VALUE
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maxOutputSize : is the size of the destination buffer (which must be already allocated)
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return : the number of bytes written in buffer 'dest'
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or 0 if the compression fails
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*/
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int LZ4_decompress_fast (const char* source, char* dest, int outputSize);
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/*
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LZ4_decompress_fast() :
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outputSize : is the original (uncompressed) size
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return : the number of bytes read from the source buffer (in other words, the compressed size)
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If the source stream is malformed, the function will stop decoding and return a negative result.
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note : This function is a bit faster than LZ4_decompress_safe()
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This function never writes outside of output buffers, but may read beyond input buffer in case of malicious data packet.
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Use this function preferably into a trusted environment (data to decode comes from a trusted source).
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Destination buffer must be already allocated. Its size must be a minimum of 'outputSize' bytes.
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*/
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int LZ4_decompress_safe_partial (const char* source, char* dest, int inputSize, int targetOutputSize, int maxOutputSize);
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/*
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LZ4_decompress_safe_partial() :
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This function decompress a compressed block of size 'inputSize' at position 'source'
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into output buffer 'dest' of size 'maxOutputSize'.
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The function tries to stop decompressing operation as soon as 'targetOutputSize' has been reached,
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reducing decompression time.
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return : the number of bytes decoded in the destination buffer (necessarily <= maxOutputSize)
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Note : this number can be < 'targetOutputSize' should the compressed block to decode be smaller.
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Always control how many bytes were decoded.
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If the source stream is detected malformed, the function will stop decoding and return a negative result.
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This function never writes outside of output buffer, and never reads outside of input buffer. It is therefore protected against malicious data packets
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*/
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int LZ4_sizeofState();
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int LZ4_compress_withState (void* state, const char* source, char* dest, int inputSize);
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int LZ4_compress_limitedOutput_withState (void* state, const char* source, char* dest, int inputSize, int maxOutputSize);
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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_sizeofState();
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Note that tables must be aligned on 4-bytes boundaries, otherwise compression will fail (return code 0).
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The allocated memory can be provided to the compressions functions using 'void* state' parameter.
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LZ4_compress_withState() and LZ4_compress_limitedOutput_withState() are equivalent to previously described functions.
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They just use the externally allocated memory area instead of allocating their own (on stack, or on heap).
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*/
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/**************************************
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Streaming Functions
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**************************************/
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void* LZ4_create (const char* inputBuffer);
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int LZ4_compress_continue (void* LZ4_Data, const char* source, char* dest, int inputSize);
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int LZ4_compress_limitedOutput_continue (void* LZ4_Data, const char* source, char* dest, int inputSize, int maxOutputSize);
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char* LZ4_slideInputBuffer (void* LZ4_Data);
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int LZ4_free (void* LZ4_Data);
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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 LZ4 Data Structure, thanks to the function :
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void* LZ4_create (const char* inputBuffer);
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The result of the function is the (void*) pointer on the LZ4 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_compress_continue() or LZ4_compress_limitedOutput_continue().
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Their behavior are identical to LZ4_compress() or LZ4_compress_limitedOutput(),
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but require the LZ4 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_slideInputBuffer(void* LZ4_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_compress_continue() or LZ4_compress_limitedOutput_continue(), as usual.
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When compression is completed, a call to LZ4_free() will release the memory used by the LZ4 Data Structure.
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*/
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int LZ4_sizeofStreamState();
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int LZ4_resetStreamState(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_create (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_sizeofStreamState();
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Note also that space must be 4-bytes aligned.
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Once space is allocated, you must initialize it using : LZ4_resetStreamState(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 on 4-bytes boundaries, 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_resetStreamState() must be 0 is OK.
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Any other value means there was an error (typically, pointer is not aligned on 4-bytes boundaries).
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*/
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int LZ4_decompress_safe_withPrefix64k (const char* source, char* dest, int inputSize, int maxOutputSize);
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int LZ4_decompress_fast_withPrefix64k (const char* source, char* dest, int outputSize);
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/*
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*_withPrefix64k() :
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These decoding functions work the same as their "normal name" versions,
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but can use up to 64KB of data in front of 'char* dest'.
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These functions are necessary to decode inter-dependant blocks.
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*/
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/**************************************
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Obsolete Functions
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**************************************/
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/*
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These functions are deprecated and should no longer be used.
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They are provided here for compatibility with existing user programs.
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*/
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static inline int LZ4_uncompress (const char* source, char* dest, int outputSize) { return LZ4_decompress_fast(source, dest, outputSize); }
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static inline int LZ4_uncompress_unknownOutputSize (const char* source, char* dest, int isize, int maxOutputSize) { return LZ4_decompress_safe(source, dest, isize, maxOutputSize); }
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#if defined (__cplusplus)
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}
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#endif
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