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315 lines
14 KiB
315 lines
14 KiB
/* |
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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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* lz4.h provides raw compression format functions, for optimal performance and integration into programs. |
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* If you need to generate data using an inter-operable format (respecting the framing specification), |
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* please use lz4frame.h instead. |
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*/ |
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/************************************** |
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Version |
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**************************************/ |
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#define LZ4_VERSION_MAJOR 1 /* for breaking interface changes */ |
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#define LZ4_VERSION_MINOR 5 /* for new (non-breaking) interface capabilities */ |
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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 sourceSize); |
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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 'sourceSize' 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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and never writes outside of output buffer, nor reads outside of input buffer. |
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It is also 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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/* |
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LZ4_compressBound() : |
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Provides the maximum size that LZ4 compression may output in a "worst case" scenario (input data not compressible) |
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This function is primarily useful for memory allocation purposes (output buffer size). |
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Macro LZ4_COMPRESSBOUND() is also provided for compilation-time evaluation (stack memory allocation for example). |
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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 'sourceSize' 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 saves time and memory on detecting non-compressible (or barely compressible) data. |
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This function never writes outside of provided output buffer. |
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sourceSize : 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 compression fails |
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*/ |
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int LZ4_compress_limitedOutput (const char* source, char* dest, int sourceSize, 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 intentionally 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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Streaming Compression Functions |
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***********************************************/ |
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#define LZ4_STREAMSIZE_U64 ((1 << (LZ4_MEMORY_USAGE-3)) + 4) |
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#define LZ4_STREAMSIZE (LZ4_STREAMSIZE_U64 * sizeof(long long)) |
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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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* note : only allocated directly the structure if you are statically linking LZ4 |
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* If you are using liblz4 as a DLL, please use below construction methods instead. |
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*/ |
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typedef struct { long long table[LZ4_STREAMSIZE_U64]; } LZ4_stream_t; |
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/* |
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* LZ4_resetStream |
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* Use this function to init an allocated LZ4_stream_t structure |
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*/ |
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void LZ4_resetStream (LZ4_stream_t* LZ4_streamPtr); |
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/* |
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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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* In the context of a DLL (liblz4), please use these methods rather than the static struct. |
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* They are more future proof, in case of a change of LZ4_stream_t size. |
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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_streamPtr); |
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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 : dictionary size, in bytes (necessarily <= 64 KB) |
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*/ |
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int LZ4_loadDict (LZ4_stream_t* LZ4_streamPtr, 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_streamPtr, 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_streamPtr, 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 safer 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 : dictionary size in bytes, or 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_streamPtr, char* safeBuffer, int dictSize); |
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/************************************************ |
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Streaming Decompression Functions |
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************************************************/ |
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#define LZ4_STREAMDECODESIZE_U64 4 |
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#define LZ4_STREAMDECODESIZE (LZ4_STREAMDECODESIZE_U64 * sizeof(unsigned long long)) |
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typedef struct { unsigned long long table[LZ4_STREAMDECODESIZE_U64]; } LZ4_streamDecode_t; |
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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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* init this structure content using LZ4_setStreamDecode or memset() before first use ! |
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* |
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* In the context of a DLL (liblz4) please prefer usage of construction methods below. |
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* They are more future proof, in case of a change of LZ4_streamDecode_t size in the future. |
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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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* LZ4_setStreamDecode |
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* Use this function to instruct where to find the dictionary. |
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* Setting a size of 0 is allowed (same effect as reset). |
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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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*_continue() : |
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These decoding functions allow decompression of multiple blocks in "streaming" mode. |
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Previously decoded blocks *must* remain available at the memory position where they were decoded (up to 64 KB) |
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If this condition is not possible, save the relevant part of decoded data into a safe buffer, |
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and indicate where is its new address using LZ4_setStreamDecode() |
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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 maxDecompressedSize); |
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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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They are stand-alone and don'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 maxDecompressedSize, 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 migrate 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 streaming functions; use new streaming 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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