323 lines
14 KiB
C
323 lines
14 KiB
C
/*
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LZ4 - Fast LZ compression algorithm
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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 source repository : http://code.google.com/p/lz4/
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- LZ4 public forum : https://groups.google.com/forum/#!forum/lz4c
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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 3 /* for minor interface/format changes */
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#define LZ4_VERSION_RELEASE 0 /* for tweaks, bug-fixes, or development */
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#define LZ4_VERSION_NUMBER (LZ4_VERSION_MAJOR *100*100 + LZ4_VERSION_MINOR *100 + LZ4_VERSION_RELEASE)
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int LZ4_versionNumber (void);
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/**************************************
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Tuning parameter
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**************************************/
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/*
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* LZ4_MEMORY_USAGE :
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* Memory usage formula : N->2^N Bytes (examples : 10 -> 1KB; 12 -> 4KB ; 16 -> 64KB; 20 -> 1MB; etc.)
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* Increasing memory usage improves compression ratio
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* Reduced memory usage can improve speed, due to cache effect
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* Default value is 14, for 16KB, which nicely fits into Intel x86 L1 cache
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*/
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#define LZ4_MEMORY_USAGE 14
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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 compressedSize, int maxDecompressedSize);
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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_SIZE
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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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compressedSize : is obviously the source size
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maxDecompressedSize : is the size of the destination buffer, which must be already allocated.
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return : the number of bytes decompressed into the destination buffer (necessarily <= maxDecompressedSize)
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If the destination buffer is not large enough, decoding will stop and output an error code (<0).
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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 :
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it never writes outside of output buffer, and never reads outside of input buffer.
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Therefore, it is protected against malicious data packets.
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*/
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/*
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Note :
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Should you prefer to explicitly allocate compression-table memory using your own allocation method,
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use the streaming functions provided below, simply reset the memory area between each call to LZ4_compress_continue()
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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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/*
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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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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_compressBound(int isize);
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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_compress_limitedOutput (const char* source, char* dest, int inputSize, int maxOutputSize);
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/*
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LZ4_compress_withState() :
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Same compression functions, but using an externally allocated memory space to store compression state.
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Use LZ4_sizeofState() to know how much memory must be allocated,
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and then, provide it as 'void* state' to compression functions.
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*/
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int LZ4_sizeofState(void);
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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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LZ4_decompress_fast() :
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originalSize : is the original and therefore 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 detected malformed, the function will stop decoding and return a negative result.
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Destination buffer must be already allocated. Its size must be a minimum of 'originalSize' bytes.
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note : This function fully respect memory boundaries for properly formed compressed data.
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It is a bit faster than LZ4_decompress_safe().
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However, it does not provide any protection against intentionnally modified data stream (malicious input).
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Use this function in trusted environment only (data to decode comes from a trusted source).
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*/
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int LZ4_decompress_fast (const char* source, char* dest, int originalSize);
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/*
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LZ4_decompress_safe_partial() :
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This function decompress a compressed block of size 'compressedSize' at position 'source'
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into destination buffer 'dest' of size 'maxDecompressedSize'.
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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 <= maxDecompressedSize)
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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_decompress_safe_partial (const char* source, char* dest, int compressedSize, int targetOutputSize, int maxDecompressedSize);
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/***********************************************
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Experimental Continuous Block Mode
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These functions allow the compression of continuous blocks,
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where each block benefits from prior 64 KB within preceding blocks to achieve better compression ratio.
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A flow of multiple continuous blocks is called a "stream".
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***********************************************/
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#define LZ4_STREAMSIZE_U32 ((1 << (LZ4_MEMORY_USAGE-2)) + 8)
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#define LZ4_STREAMSIZE (LZ4_STREAMSIZE_U32 * sizeof(unsigned int))
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/*
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* LZ4_stream_t
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* information structure to track an LZ4 stream.
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* important : init this structure content before first use !
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*/
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typedef struct { unsigned int table[LZ4_STREAMSIZE_U32]; } LZ4_stream_t;
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/*
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* LZ4_resetStream
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* Use this function to init a newly allocated LZ4_stream_t structure
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* You can also reset an existing LZ4_stream_t structure
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*/
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void LZ4_resetStream (LZ4_stream_t* LZ4_stream);
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/*
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* If you prefer dynamic allocation methods,
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* LZ4_createStream will allocate and initialize an LZ4_stream_t structure
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* LZ4_freeStream releases its memory.
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*/
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LZ4_stream_t* LZ4_createStream(void);
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int LZ4_freeStream (LZ4_stream_t* LZ4_stream);
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/*
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* LZ4_loadDict
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* Use this function to load a static dictionary into LZ4_stream.
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* Any previous data will be forgotten, only 'dictionary' will remain in memory.
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* Loading a size of 0 is allowed.
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* Return : 1 if OK, 0 if error
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*/
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int LZ4_loadDict (LZ4_stream_t* LZ4_stream, const char* dictionary, int dictSize);
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/*
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* LZ4_compress_continue
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* Compress data block 'source', using blocks compressed before as dictionary to improve compression ratio
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* Previous data blocks are assumed to still be present at their previous location.
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*/
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int LZ4_compress_continue (LZ4_stream_t* LZ4_stream, const char* source, char* dest, int inputSize);
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/*
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* LZ4_compress_limitedOutput_continue
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* Same as before, but also specify a maximum target compressed size (maxOutputSize)
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* If objective cannot be met, compression exits, and returns a zero.
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*/
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int LZ4_compress_limitedOutput_continue (LZ4_stream_t* LZ4_stream, const char* source, char* dest, int inputSize, int maxOutputSize);
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/*
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* LZ4_saveDict
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* If previously compressed data block is not guaranteed to remain available at its memory location
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* save it into a safe place (char* safeBuffer)
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* Note : you don't need to call LZ4_loadDict() afterwards,
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* dictionary is immediately usable, you can therefore call again LZ4_compress_continue()
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* Return : 1 if OK, 0 if error
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* Note : any dictSize > 64 KB will be interpreted as 64KB.
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*/
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int LZ4_saveDict (LZ4_stream_t* LZ4_stream, char* safeBuffer, int dictSize);
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/************************************************
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Experimental CBM Decompression Functions
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************************************************/
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#define LZ4_STREAMDECODESIZE_U32 4
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#define LZ4_STREAMDECODESIZE (LZ4_STREAMDECODESIZE_U32 * sizeof(unsigned int))
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/*
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* LZ4_streamDecode_t
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* information structure to track an LZ4 stream.
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* important : init this structure content using LZ4_setStreamDecode or memset() before first use !
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*/
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typedef struct { unsigned int table[LZ4_STREAMDECODESIZE_U32]; } LZ4_streamDecode_t;
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/*
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* LZ4_setStreamDecode
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* Use this function to instruct where to find the dictionary.
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* This function can be used to specify a static dictionary,
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* or to instruct where to find some previously decoded data saved into a different memory space.
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* Setting a size of 0 is allowed (same effect as no dictionary).
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* Return : 1 if OK, 0 if error
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*/
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int LZ4_setStreamDecode (LZ4_streamDecode_t* LZ4_streamDecode, const char* dictionary, int dictSize);
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/*
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* If you prefer dynamic allocation methods,
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* LZ4_createStreamDecode will allocate and initialize an LZ4_streamDecode_t structure
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* LZ4_freeStreamDecode releases its memory.
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*/
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LZ4_streamDecode_t* LZ4_createStreamDecode(void);
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int LZ4_freeStreamDecode (LZ4_streamDecode_t* LZ4_stream);
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/*
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*_continue() :
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These decoding functions allow decompression of multiple blocks in "streaming" mode.
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Previously decoded blocks must still be available at the memory position where they were decoded.
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If it's not possible, save the relevant part of decoded data into a safe buffer,
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and indicate where its new address using LZ4_setDictDecode()
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*/
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int LZ4_decompress_safe_continue (LZ4_streamDecode_t* LZ4_streamDecode, const char* source, char* dest, int compressedSize, int maxOutputSize);
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int LZ4_decompress_fast_continue (LZ4_streamDecode_t* LZ4_streamDecode, const char* source, char* dest, int originalSize);
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/*
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Advanced decoding functions :
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*_usingDict() :
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These decoding functions work the same as
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a combination of LZ4_setDictDecode() followed by LZ4_decompress_x_continue()
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all together into a single function call.
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It doesn't use nor update an LZ4_streamDecode_t structure.
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*/
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int LZ4_decompress_safe_usingDict (const char* source, char* dest, int compressedSize, int maxOutputSize, const char* dictStart, int dictSize);
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int LZ4_decompress_fast_usingDict (const char* source, char* dest, int originalSize, const char* dictStart, int dictSize);
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/**************************************
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Obsolete Functions
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**************************************/
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/*
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Obsolete decompression functions
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These function names are deprecated and should no longer be used.
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They are only provided here for compatibility with older user programs.
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- LZ4_uncompress is the same as LZ4_decompress_fast
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- LZ4_uncompress_unknownOutputSize is the same as LZ4_decompress_safe
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These function prototypes are now disabled; uncomment them if you really need them.
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It is highly recommended to stop using these functions and migrated to newer ones */
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/* int LZ4_uncompress (const char* source, char* dest, int outputSize); */
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/* int LZ4_uncompress_unknownOutputSize (const char* source, char* dest, int isize, int maxOutputSize); */
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/* Obsolete CBM functions; use new CBM interface whenever possible */
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void* LZ4_create (const char* inputBuffer);
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int LZ4_sizeofStreamState(void);
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int LZ4_resetStreamState(void* state, const char* inputBuffer);
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char* LZ4_slideInputBuffer (void* state);
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/* Obsolete streaming decoding functions */
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int LZ4_decompress_safe_withPrefix64k (const char* source, char* dest, int compressedSize, int maxOutputSize);
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int LZ4_decompress_fast_withPrefix64k (const char* source, char* dest, int originalSize);
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#if defined (__cplusplus)
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}
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#endif
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