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author | Yann Collet <yann.collet.73@gmail.com> | 2014-11-30 22:32:12 (GMT) |
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committer | Yann Collet <yann.collet.73@gmail.com> | 2014-11-30 22:32:12 (GMT) |
commit | d008c87151abf8c36a9f98d28461bf6f3dfdc6ae (patch) | |
tree | f9cbf5a95577a4bbbe610b1dca00e1f332e56623 /lib/lz4hc.h | |
parent | 80030c16fff7a8a5dae18cf2b1ab5da508137847 (diff) | |
download | lz4-d008c87151abf8c36a9f98d28461bf6f3dfdc6ae.zip lz4-d008c87151abf8c36a9f98d28461bf6f3dfdc6ae.tar.gz lz4-d008c87151abf8c36a9f98d28461bf6f3dfdc6ae.tar.bz2 |
New directory structure : library source files into /lib directory
Diffstat (limited to 'lib/lz4hc.h')
-rw-r--r-- | lib/lz4hc.h | 223 |
1 files changed, 223 insertions, 0 deletions
diff --git a/lib/lz4hc.h b/lib/lz4hc.h new file mode 100644 index 0000000..26ba6d3 --- /dev/null +++ b/lib/lz4hc.h @@ -0,0 +1,223 @@ +/* + LZ4 HC - High Compression Mode of LZ4 + 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 homepage : http://fastcompression.blogspot.com/p/lz4.html + - LZ4 source repository : http://code.google.com/p/lz4/ +*/ +#pragma once + + +#if defined (__cplusplus) +extern "C" { +#endif + + +int LZ4_compressHC (const char* source, char* dest, int inputSize); +/* +LZ4_compressHC : + return : the number of bytes in compressed buffer dest + or 0 if compression fails. + note : destination buffer must be already allocated. + To avoid any problem, size it to handle worst cases situations (input data not compressible) + Worst case size evaluation is provided by function LZ4_compressBound() (see "lz4.h") +*/ + +int LZ4_compressHC_limitedOutput (const char* source, char* dest, int inputSize, int maxOutputSize); +/* +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 1 GB + maxOutputSize : is maximum allowed size into the destination buffer (which must be already allocated) + return : the number of output bytes written in buffer 'dest' + or 0 if compression fails. +*/ + + +int LZ4_compressHC2 (const char* source, char* dest, int inputSize, int compressionLevel); +int LZ4_compressHC2_limitedOutput (const char* source, char* dest, int inputSize, int maxOutputSize, int compressionLevel); +/* + Same functions as above, but with programmable 'compressionLevel'. + Recommended values are between 4 and 9, although any value between 0 and 16 will work. + 'compressionLevel'==0 means use default 'compressionLevel' value. + Values above 16 behave the same as 16. + Equivalent variants exist for all other compression functions below. +*/ + +/* Note : + Decompression functions are provided within LZ4 source code (see "lz4.h") (BSD license) +*/ + + +/************************************** + Using an external allocation +**************************************/ +int LZ4_sizeofStateHC(void); +int LZ4_compressHC_withStateHC (void* state, const char* source, char* dest, int inputSize); +int LZ4_compressHC_limitedOutput_withStateHC (void* state, const char* source, char* dest, int inputSize, int maxOutputSize); + +int LZ4_compressHC2_withStateHC (void* state, const char* source, char* dest, int inputSize, int compressionLevel); +int LZ4_compressHC2_limitedOutput_withStateHC(void* state, const char* source, char* dest, int inputSize, int maxOutputSize, int compressionLevel); + +/* +These functions are provided should you prefer to allocate memory for compression tables with your own allocation methods. +To know how much memory must be allocated for the compression tables, use : +int LZ4_sizeofStateHC(); + +Note that tables must be aligned for pointer (32 or 64 bits), otherwise compression will fail (return code 0). + +The allocated memory can be provided to the compression functions using 'void* state' parameter. +LZ4_compress_withStateHC() and LZ4_compress_limitedOutput_withStateHC() are equivalent to previously described functions. +They just use the externally allocated memory for state instead of allocating their own (on stack, or on heap). +*/ + + + +/************************************** + Experimental Streaming Functions +**************************************/ +#define LZ4_STREAMHCSIZE_U64 32774 +#define LZ4_STREAMHCSIZE (LZ4_STREAMHCSIZE_U64 * sizeof(unsigned long long)) +typedef struct { unsigned long long table[LZ4_STREAMHCSIZE_U64]; } LZ4_streamHC_t; + +/* +This structure allows static allocation of LZ4 HC streaming state. +State must then be initialized using LZ4_resetStreamHC() before first use. + +If you prefer dynamic allocation, please refer to functions below. +*/ + +LZ4_streamHC_t* LZ4_createStreamHC(void); +int LZ4_freeStreamHC (LZ4_streamHC_t* LZ4_streamHCPtr); + +/* +These functions create and release memory for LZ4 HC streaming state. +Newly created states are already initialized. +Existing state space can be re-used anytime using LZ4_resetStreamHC(). +*/ + +void LZ4_resetStreamHC (LZ4_streamHC_t* LZ4_streamHCPtr, int compressionLevel); +int LZ4_loadDictHC (LZ4_streamHC_t* LZ4_streamHCPtr, const char* dictionary, int dictSize); + +int LZ4_compressHC_continue (LZ4_streamHC_t* LZ4_streamHCPtr, const char* source, char* dest, int inputSize); +int LZ4_compressHC_limitedOutput_continue (LZ4_streamHC_t* LZ4_streamHCPtr, const char* source, char* dest, int inputSize, int maxOutputSize); + +int LZ4_saveDictHC (LZ4_streamHC_t* LZ4_streamHCPtr, char* safeBuffer, int maxDictSize); + +/* +These functions compress data in successive blocks of any size, using previous blocks as dictionary. +One key assumption is that each previous block will remain read-accessible while compressing next block. + +Before starting compression, state must be properly initialized, using LZ4_resetStreamHC(). +A first "fictional block" can then be designated as initial dictionary, using LZ4_loadDictHC() (Optional). + +Then, use LZ4_compressHC_continue() or LZ4_compressHC_limitedOutput_continue() to compress each successive block. +They work like usual LZ4_compressHC() or LZ4_compressHC_limitedOutput(), but use previous memory blocks to improve compression. +Previous memory blocks (including initial dictionary when present) must remain accessible and unmodified during compression. + +If, for any reason, previous data block can't be preserved in memory during next compression block, +you must save it to a safer memory space, +using LZ4_saveDictHC(). +*/ + + + +/************************************** + Deprecated Streaming Functions +**************************************/ +/* Note : these streaming functions still follows the older model */ +void* LZ4_createHC (const char* inputBuffer); +//int LZ4_compressHC_continue (void* LZ4HC_Data, const char* source, char* dest, int inputSize); +//int LZ4_compressHC_limitedOutput_continue (void* LZ4HC_Data, const char* source, char* dest, int inputSize, int maxOutputSize); +char* LZ4_slideInputBufferHC (void* LZ4HC_Data); +int LZ4_freeHC (void* LZ4HC_Data); + +int LZ4_compressHC2_continue (void* LZ4HC_Data, const char* source, char* dest, int inputSize, int compressionLevel); +int LZ4_compressHC2_limitedOutput_continue (void* LZ4HC_Data, const char* source, char* dest, int inputSize, int maxOutputSize, int compressionLevel); + +/* +These functions allow the compression of dependent blocks, where each block benefits from prior 64 KB within preceding blocks. +In order to achieve this, it is necessary to start creating the LZ4HC Data Structure, thanks to the function : + +void* LZ4_createHC (const char* inputBuffer); +The result of the function is the (void*) pointer on the LZ4HC Data Structure. +This pointer will be needed in all other functions. +If the pointer returned is NULL, then the allocation has failed, and compression must be aborted. +The only parameter 'const char* inputBuffer' must, obviously, point at the beginning of input buffer. +The input buffer must be already allocated, and size at least 192KB. +'inputBuffer' will also be the 'const char* source' of the first block. + +All blocks are expected to lay next to each other within the input buffer, starting from 'inputBuffer'. +To compress each block, use either LZ4_compressHC_continue() or LZ4_compressHC_limitedOutput_continue(). +Their behavior are identical to LZ4_compressHC() or LZ4_compressHC_limitedOutput(), +but require the LZ4HC Data Structure as their first argument, and check that each block starts right after the previous one. +If next block does not begin immediately after the previous one, the compression will fail (return 0). + +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 : +char* LZ4_slideInputBufferHC(void* LZ4HC_Data); +must be performed. It will typically copy the latest 64KB of input at the beginning of input buffer. +Note that, for this function to work properly, minimum size of an input buffer must be 192KB. +==> The memory position where the next input data block must start is provided as the result of the function. + +Compression can then resume, using LZ4_compressHC_continue() or LZ4_compressHC_limitedOutput_continue(), as usual. + +When compression is completed, a call to LZ4_freeHC() will release the memory used by the LZ4HC Data Structure. +*/ + +int LZ4_sizeofStreamStateHC(void); +int LZ4_resetStreamStateHC(void* state, const char* inputBuffer); + +/* +These functions achieve the same result as : +void* LZ4_createHC (const char* inputBuffer); + +They are provided here to allow the user program to allocate memory using its own routines. + +To know how much space must be allocated, use LZ4_sizeofStreamStateHC(); +Note also that space must be aligned for pointers (32 or 64 bits). + +Once space is allocated, you must initialize it using : LZ4_resetStreamStateHC(void* state, const char* inputBuffer); +void* state is a pointer to the space allocated. +It must be aligned for pointers (32 or 64 bits), and be large enough. +The parameter 'const char* inputBuffer' must, obviously, point at the beginning of input buffer. +The input buffer must be already allocated, and size at least 192KB. +'inputBuffer' will also be the 'const char* source' of the first block. + +The same space can be re-used multiple times, just by initializing it each time with LZ4_resetStreamState(). +return value of LZ4_resetStreamStateHC() must be 0 is OK. +Any other value means there was an error (typically, state is not aligned for pointers (32 or 64 bits)). +*/ + + +#if defined (__cplusplus) +} +#endif |