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Diffstat (limited to 'mfbt/lz4.h')
| -rw-r--r-- | mfbt/lz4.h | 276 |
1 files changed, 276 insertions, 0 deletions
diff --git a/mfbt/lz4.h b/mfbt/lz4.h new file mode 100644 index 000000000..bf6780122 --- /dev/null +++ b/mfbt/lz4.h @@ -0,0 +1,276 @@ +/* + LZ4 - Fast LZ compression algorithm + 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 source repository : http://code.google.com/p/lz4/ + - LZ4 public forum : https://groups.google.com/forum/#!forum/lz4c +*/ +#pragma once + +#if defined (__cplusplus) +extern "C" { +#endif + + +/************************************** + Version +**************************************/ +#define LZ4_VERSION_MAJOR 1 /* for major interface/format changes */ +#define LZ4_VERSION_MINOR 2 /* for minor interface/format changes */ +#define LZ4_VERSION_RELEASE 0 /* for tweaks, bug-fixes, or development */ + + +/************************************** + Tuning parameter +**************************************/ +/* + * LZ4_MEMORY_USAGE : + * Memory usage formula : N->2^N Bytes (examples : 10 -> 1KB; 12 -> 4KB ; 16 -> 64KB; 20 -> 1MB; etc.) + * Increasing memory usage improves compression ratio + * Reduced memory usage can improve speed, due to cache effect + * Default value is 14, for 16KB, which nicely fits into Intel x86 L1 cache + */ +#define LZ4_MEMORY_USAGE 14 + + +/************************************** + Simple Functions +**************************************/ + +int LZ4_compress (const char* source, char* dest, int inputSize); +int LZ4_decompress_safe (const char* source, char* dest, int compressedSize, int maxOutputSize); + +/* +LZ4_compress() : + Compresses 'inputSize' bytes from 'source' into 'dest'. + Destination buffer must be already allocated, + and must be sized to handle worst cases situations (input data not compressible) + Worst case size evaluation is provided by function LZ4_compressBound() + inputSize : Max supported value is LZ4_MAX_INPUT_VALUE + return : the number of bytes written in buffer dest + or 0 if the compression fails + +LZ4_decompress_safe() : + compressedSize : is obviously the source size + maxOutputSize : is the size of the destination buffer, which must be already allocated. + return : the number of bytes decoded in the destination buffer (necessarily <= maxOutputSize) + If the destination buffer is not large enough, decoding will stop and output an error code (<0). + If the source stream is detected malformed, the function will stop decoding and return a negative result. + This function is protected against buffer overflow exploits : + it never writes outside of output buffer, and never reads outside of input buffer. + Therefore, it is protected against malicious data packets. +*/ + + +/* +Note : + Should you prefer to explicitly allocate compression-table memory using your own allocation method, + use the streaming functions provided below, simply reset the memory area between each call to LZ4_compress_continue() +*/ + + +/************************************** + Advanced Functions +**************************************/ +#define LZ4_MAX_INPUT_SIZE 0x7E000000 /* 2 113 929 216 bytes */ +#define LZ4_COMPRESSBOUND(isize) ((unsigned int)(isize) > (unsigned int)LZ4_MAX_INPUT_SIZE ? 0 : (isize) + ((isize)/255) + 16) + +/* +LZ4_compressBound() : + Provides the maximum size that LZ4 may output in a "worst case" scenario (input data not compressible) + primarily useful for memory allocation of output buffer. + macro is also provided when result needs to be evaluated at compilation (such as stack memory allocation). + + isize : is the input size. Max supported value is LZ4_MAX_INPUT_SIZE + return : maximum output size in a "worst case" scenario + or 0, if input size is too large ( > LZ4_MAX_INPUT_SIZE) +*/ +int LZ4_compressBound(int isize); + + +/* +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 LZ4_MAX_INPUT_VALUE + maxOutputSize : is the size of the destination buffer (which must be already allocated) + return : the number of bytes written in buffer 'dest' + or 0 if the compression fails +*/ +int LZ4_compress_limitedOutput (const char* source, char* dest, int inputSize, int maxOutputSize); + + +/* +LZ4_decompress_fast() : + originalSize : is the original and therefore uncompressed size + return : the number of bytes read from the source buffer (in other words, the compressed size) + If the source stream is malformed, the function will stop decoding and return a negative result. + Destination buffer must be already allocated. Its size must be a minimum of 'originalSize' bytes. + note : This function is a bit faster than LZ4_decompress_safe() + It provides fast decompression and fully respect memory boundaries for properly formed compressed data. + It does not provide full protection against intentionnally modified data stream. + Use this function in a trusted environment (data to decode comes from a trusted source). +*/ +int LZ4_decompress_fast (const char* source, char* dest, int originalSize); + + +/* +LZ4_decompress_safe_partial() : + This function decompress a compressed block of size 'compressedSize' at position 'source' + into output buffer 'dest' of size 'maxOutputSize'. + The function tries to stop decompressing operation as soon as 'targetOutputSize' has been reached, + reducing decompression time. + return : the number of bytes decoded in the destination buffer (necessarily <= maxOutputSize) + Note : this number can be < 'targetOutputSize' should the compressed block to decode be smaller. + Always control how many bytes were decoded. + If the source stream is detected malformed, the function will stop decoding and return a negative result. + This function never writes outside of output buffer, and never reads outside of input buffer. It is therefore protected against malicious data packets +*/ +int LZ4_decompress_safe_partial (const char* source, char* dest, int compressedSize, int targetOutputSize, int maxOutputSize); + + +/*********************************************** + Experimental Streaming Compression Functions +***********************************************/ + +#define LZ4_STREAMSIZE_U32 ((1 << (LZ4_MEMORY_USAGE-2)) + 8) +#define LZ4_STREAMSIZE (LZ4_STREAMSIZE_U32 * sizeof(unsigned int)) +/* + * LZ4_stream_t + * information structure to track an LZ4 stream. + * important : set this structure content to zero before first use ! + */ +typedef struct { unsigned int table[LZ4_STREAMSIZE_U32]; } LZ4_stream_t; + +/* + * If you prefer dynamic allocation methods, + * LZ4_createStream + * provides a pointer (void*) towards an initialized LZ4_stream_t structure. + * LZ4_free just frees it. + */ +void* LZ4_createStream(); +int LZ4_free (void* LZ4_stream); + + +/* + * LZ4_loadDict + * Use this function to load a static dictionary into LZ4_stream. + * Any previous data will be forgotten, only 'dictionary' will remain in memory. + * Loading a size of 0 is allowed (same effect as init). + * Return : 1 if OK, 0 if error + */ +int LZ4_loadDict (void* LZ4_stream, const char* dictionary, int dictSize); + +/* + * LZ4_compress_continue + * Compress data block 'source', using blocks compressed before as dictionary to improve compression ratio + * Previous data blocks are assumed to still be present at their previous location. + */ +int LZ4_compress_continue (void* LZ4_stream, const char* source, char* dest, int inputSize); + +/* + * LZ4_compress_limitedOutput_continue + * Same as before, but also specify a maximum target compressed size (maxOutputSize) + * If objective cannot be met, compression exits, and returns a zero. + */ +int LZ4_compress_limitedOutput_continue (void* LZ4_stream, const char* source, char* dest, int inputSize, int maxOutputSize); + +/* + * LZ4_saveDict + * If previously compressed data block is not guaranteed to remain at its previous memory location + * save it into a safe place (char* safeBuffer) + * Note : you don't need to call LZ4_loadDict() afterwards, + * dictionary is immediately usable, you can therefore call again LZ4_compress_continue() + * Return : 1 if OK, 0 if error + * Note : any dictSize > 64 KB will be interpreted as 64KB. + */ +int LZ4_saveDict (void* LZ4_stream, char* safeBuffer, int dictSize); + + +/************************************************ + Experimental Streaming Decompression Functions +************************************************/ + +#define LZ4_STREAMDECODESIZE_U32 4 +#define LZ4_STREAMDECODESIZE (LZ4_STREAMDECODESIZE_U32 * sizeof(unsigned int)) +/* + * LZ4_streamDecode_t + * information structure to track an LZ4 stream. + * important : set this structure content to zero before first use ! + */ +typedef struct { unsigned int table[LZ4_STREAMDECODESIZE_U32]; } LZ4_streamDecode_t; + +/* + * If you prefer dynamic allocation methods, + * LZ4_createStreamDecode() + * provides a pointer (void*) towards an initialized LZ4_streamDecode_t structure. + * LZ4_free just frees it. + */ +void* LZ4_createStreamDecode(); +int LZ4_free (void* LZ4_stream); /* yes, it's the same one as for compression */ + +/* +*_continue() : + These decoding functions allow decompression of multiple blocks in "streaming" mode. + Previously decoded blocks must still be available at the memory position where they were decoded. + If it's not possible, save the relevant part of decoded data into a safe buffer, + and indicate where it stands using LZ4_setDictDecode() +*/ +int LZ4_decompress_safe_continue (void* LZ4_streamDecode, const char* source, char* dest, int compressedSize, int maxOutputSize); +int LZ4_decompress_fast_continue (void* LZ4_streamDecode, const char* source, char* dest, int originalSize); + +/* + * LZ4_setDictDecode + * Use this function to instruct where to find the dictionary. + * This function can be used to specify a static dictionary, + * or to instruct where to find some previously decoded data saved into a different memory space. + * Setting a size of 0 is allowed (same effect as no dictionary). + * Return : 1 if OK, 0 if error + */ +int LZ4_setDictDecode (void* LZ4_streamDecode, const char* dictionary, int dictSize); + + +/* +Advanced decoding functions : +*_usingDict() : + These decoding functions work the same as + a combination of LZ4_setDictDecode() followed by LZ4_decompress_x_continue() + all together into a single function call. + It doesn't use nor update an LZ4_streamDecode_t structure. +*/ +int LZ4_decompress_safe_usingDict (const char* source, char* dest, int compressedSize, int maxOutputSize, const char* dictStart, int dictSize); +int LZ4_decompress_fast_usingDict (const char* source, char* dest, int originalSize, const char* dictStart, int dictSize); + + + +#if defined (__cplusplus) +} +#endif |