121 lines
5.1 KiB
C
121 lines
5.1 KiB
C
/*
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LZ4 - Fast LZ compression algorithm
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Header File
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Copyright (C) 2011-2012, 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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// Simple Functions
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//****************************
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int LZ4_compress (const char* source, char* dest, int isize);
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int LZ4_uncompress (const char* source, char* dest, int osize);
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/*
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LZ4_compress() :
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isize : is the input size. Max supported value is ~1.9GB
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return : the number of bytes written in buffer dest
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or 0 if the compression fails (if LZ4_COMPRESSMIN is set)
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note : destination buffer must be already allocated.
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destination buffer 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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LZ4_uncompress() :
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osize : is the output size, therefore the original size
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return : the number of bytes read in the source buffer
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If the source stream is malformed, the function will stop decoding and return a negative result, indicating the byte position of the faulty instruction
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This function never writes beyond dest + osize, and is therefore protected against malicious data packets
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note : destination buffer must be already allocated
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*/
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//****************************
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// Advanced Functions
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//****************************
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int LZ4_compressBound(int 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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isize : is the input size. Max supported value is ~1.9GB
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return : maximum output size in a "worst case" scenario
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note : this function is limited by "int" range (2^31-1)
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*/
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int LZ4_uncompress_unknownOutputSize (const char* source, char* dest, int isize, int maxOutputSize);
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/*
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LZ4_uncompress_unknownOutputSize() :
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isize : is the input size, therefore the compressed size
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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 malformed, the function will stop decoding and return a negative result, indicating the byte position of the faulty instruction
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This function never writes beyond dest + maxOutputSize, and is therefore protected against malicious data packets
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note : Destination buffer must be already allocated.
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This version is slightly slower than LZ4_uncompress()
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*/
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int LZ4_compressCtx(void** ctx, const char* source, char* dest, int isize);
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int LZ4_compress64kCtx(void** ctx, const char* source, char* dest, int isize);
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/*
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LZ4_compressCtx() :
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This function explicitly handles the CTX memory structure.
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It avoids allocating/deallocating memory between each call, improving performance when malloc is heavily invoked.
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This function is only useful when memory is allocated into the heap (HASH_LOG value beyond STACK_LIMIT)
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Performance difference will be noticeable only when repetitively calling the compression function over many small segments.
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Note : by default, memory is allocated into the stack, therefore "malloc" is not invoked.
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LZ4_compress64kCtx() :
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Same as LZ4_compressCtx(), but specific to small inputs (<64KB).
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isize *Must* be <64KB, otherwise the output will be corrupted.
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On first call : provide a *ctx=NULL; It will be automatically allocated.
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On next calls : reuse the same ctx pointer.
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Use different pointers for different threads when doing multi-threading.
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*/
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#if defined (__cplusplus)
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}
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#endif
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