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| /* | |
| LZ4 HC - High Compression Mode of LZ4 | |
| Header File | |
| Copyright (C) 2011-2020, 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 : https://github.com/lz4/lz4 | |
| - LZ4 public forum : https://groups.google.com/forum/#!forum/lz4c | |
| */ | |
| extern "C" { | |
| /* --- Dependency --- */ | |
| /* note : lz4hc requires lz4.h/lz4.c for compilation */ | |
| /* --- Useful constants --- */ | |
| /*-************************************ | |
| * Block Compression | |
| **************************************/ | |
| /*! LZ4_compress_HC() : | |
| * Compress data from `src` into `dst`, using the powerful but slower "HC" algorithm. | |
| * `dst` must be already allocated. | |
| * Compression is guaranteed to succeed if `dstCapacity >= LZ4_compressBound(srcSize)` (see "lz4.h") | |
| * Max supported `srcSize` value is LZ4_MAX_INPUT_SIZE (see "lz4.h") | |
| * `compressionLevel` : any value between 1 and LZ4HC_CLEVEL_MAX will work. | |
| * Values > LZ4HC_CLEVEL_MAX behave the same as LZ4HC_CLEVEL_MAX. | |
| * @return : the number of bytes written into 'dst' | |
| * or 0 if compression fails. | |
| */ | |
| LZ4LIB_API int LZ4_compress_HC (const char* src, char* dst, int srcSize, int dstCapacity, int compressionLevel); | |
| /* Note : | |
| * Decompression functions are provided within "lz4.h" (BSD license) | |
| */ | |
| /*! LZ4_compress_HC_extStateHC() : | |
| * Same as LZ4_compress_HC(), but using an externally allocated memory segment for `state`. | |
| * `state` size is provided by LZ4_sizeofStateHC(). | |
| * Memory segment must be aligned on 8-bytes boundaries (which a normal malloc() should do properly). | |
| */ | |
| LZ4LIB_API int LZ4_sizeofStateHC(void); | |
| LZ4LIB_API int LZ4_compress_HC_extStateHC(void* stateHC, const char* src, char* dst, int srcSize, int maxDstSize, int compressionLevel); | |
| /*! LZ4_compress_HC_destSize() : v1.9.0+ | |
| * Will compress as much data as possible from `src` | |
| * to fit into `targetDstSize` budget. | |
| * Result is provided in 2 parts : | |
| * @return : the number of bytes written into 'dst' (necessarily <= targetDstSize) | |
| * or 0 if compression fails. | |
| * `srcSizePtr` : on success, *srcSizePtr is updated to indicate how much bytes were read from `src` | |
| */ | |
| LZ4LIB_API int LZ4_compress_HC_destSize(void* stateHC, | |
| const char* src, char* dst, | |
| int* srcSizePtr, int targetDstSize, | |
| int compressionLevel); | |
| /*-************************************ | |
| * Streaming Compression | |
| * Bufferless synchronous API | |
| **************************************/ | |
| typedef union LZ4_streamHC_u LZ4_streamHC_t; /* incomplete type (defined later) */ | |
| /*! LZ4_createStreamHC() and LZ4_freeStreamHC() : | |
| * These functions create and release memory for LZ4 HC streaming state. | |
| * Newly created states are automatically initialized. | |
| * A same state can be used multiple times consecutively, | |
| * starting with LZ4_resetStreamHC_fast() to start a new stream of blocks. | |
| */ | |
| LZ4LIB_API LZ4_streamHC_t* LZ4_createStreamHC(void); | |
| LZ4LIB_API int LZ4_freeStreamHC (LZ4_streamHC_t* streamHCPtr); | |
| /* | |
| These functions compress data in successive blocks of any size, | |
| using previous blocks as dictionary, to improve compression ratio. | |
| One key assumption is that previous blocks (up to 64 KB) remain read-accessible while compressing next blocks. | |
| There is an exception for ring buffers, which can be smaller than 64 KB. | |
| Ring-buffer scenario is automatically detected and handled within LZ4_compress_HC_continue(). | |
| Before starting compression, state must be allocated and properly initialized. | |
| LZ4_createStreamHC() does both, though compression level is set to LZ4HC_CLEVEL_DEFAULT. | |
| Selecting the compression level can be done with LZ4_resetStreamHC_fast() (starts a new stream) | |
| or LZ4_setCompressionLevel() (anytime, between blocks in the same stream) (experimental). | |
| LZ4_resetStreamHC_fast() only works on states which have been properly initialized at least once, | |
| which is automatically the case when state is created using LZ4_createStreamHC(). | |
| After reset, a first "fictional block" can be designated as initial dictionary, | |
| using LZ4_loadDictHC() (Optional). | |
| Note: In order for LZ4_loadDictHC() to create the correct data structure, | |
| it is essential to set the compression level _before_ loading the dictionary. | |
| Invoke LZ4_compress_HC_continue() to compress each successive block. | |
| The number of blocks is unlimited. | |
| Previous input blocks, including initial dictionary when present, | |
| must remain accessible and unmodified during compression. | |
| It's allowed to update compression level anytime between blocks, | |
| using LZ4_setCompressionLevel() (experimental). | |
| @dst buffer should be sized to handle worst case scenarios | |
| (see LZ4_compressBound(), it ensures compression success). | |
| In case of failure, the API does not guarantee recovery, | |
| so the state _must_ be reset. | |
| To ensure compression success | |
| whenever @dst buffer size cannot be made >= LZ4_compressBound(), | |
| consider using LZ4_compress_HC_continue_destSize(). | |
| Whenever previous input blocks can't be preserved unmodified in-place during compression of next blocks, | |
| it's possible to copy the last blocks into a more stable memory space, using LZ4_saveDictHC(). | |
| Return value of LZ4_saveDictHC() is the size of dictionary effectively saved into 'safeBuffer' (<= 64 KB) | |
| After completing a streaming compression, | |
| it's possible to start a new stream of blocks, using the same LZ4_streamHC_t state, | |
| just by resetting it, using LZ4_resetStreamHC_fast(). | |
| */ | |
| LZ4LIB_API void LZ4_resetStreamHC_fast(LZ4_streamHC_t* streamHCPtr, int compressionLevel); /* v1.9.0+ */ | |
| LZ4LIB_API int LZ4_loadDictHC (LZ4_streamHC_t* streamHCPtr, const char* dictionary, int dictSize); | |
| LZ4LIB_API int LZ4_compress_HC_continue (LZ4_streamHC_t* streamHCPtr, | |
| const char* src, char* dst, | |
| int srcSize, int maxDstSize); | |
| /*! LZ4_compress_HC_continue_destSize() : v1.9.0+ | |
| * Similar to LZ4_compress_HC_continue(), | |
| * but will read as much data as possible from `src` | |
| * to fit into `targetDstSize` budget. | |
| * Result is provided into 2 parts : | |
| * @return : the number of bytes written into 'dst' (necessarily <= targetDstSize) | |
| * or 0 if compression fails. | |
| * `srcSizePtr` : on success, *srcSizePtr will be updated to indicate how much bytes were read from `src`. | |
| * Note that this function may not consume the entire input. | |
| */ | |
| LZ4LIB_API int LZ4_compress_HC_continue_destSize(LZ4_streamHC_t* LZ4_streamHCPtr, | |
| const char* src, char* dst, | |
| int* srcSizePtr, int targetDstSize); | |
| LZ4LIB_API int LZ4_saveDictHC (LZ4_streamHC_t* streamHCPtr, char* safeBuffer, int maxDictSize); | |
| /*! LZ4_attach_HC_dictionary() : stable since v1.10.0 | |
| * This API allows for the efficient re-use of a static dictionary many times. | |
| * | |
| * Rather than re-loading the dictionary buffer into a working context before | |
| * each compression, or copying a pre-loaded dictionary's LZ4_streamHC_t into a | |
| * working LZ4_streamHC_t, this function introduces a no-copy setup mechanism, | |
| * in which the working stream references the dictionary stream in-place. | |
| * | |
| * Several assumptions are made about the state of the dictionary stream. | |
| * Currently, only streams which have been prepared by LZ4_loadDictHC() should | |
| * be expected to work. | |
| * | |
| * Alternatively, the provided dictionary stream pointer may be NULL, in which | |
| * case any existing dictionary stream is unset. | |
| * | |
| * A dictionary should only be attached to a stream without any history (i.e., | |
| * a stream that has just been reset). | |
| * | |
| * The dictionary will remain attached to the working stream only for the | |
| * current stream session. Calls to LZ4_resetStreamHC(_fast) will remove the | |
| * dictionary context association from the working stream. The dictionary | |
| * stream (and source buffer) must remain in-place / accessible / unchanged | |
| * through the lifetime of the stream session. | |
| */ | |
| LZ4LIB_API void | |
| LZ4_attach_HC_dictionary(LZ4_streamHC_t* working_stream, | |
| const LZ4_streamHC_t* dictionary_stream); | |
| /*^********************************************** | |
| * !!!!!! STATIC LINKING ONLY !!!!!! | |
| ***********************************************/ | |
| /*-****************************************************************** | |
| * PRIVATE DEFINITIONS : | |
| * Do not use these definitions directly. | |
| * They are merely exposed to allow static allocation of `LZ4_streamHC_t`. | |
| * Declare an `LZ4_streamHC_t` directly, rather than any type below. | |
| * Even then, only do so in the context of static linking, as definitions may change between versions. | |
| ********************************************************************/ | |
| /* Never ever use these definitions directly ! | |
| * Declare or allocate an LZ4_streamHC_t instead. | |
| **/ | |
| typedef struct LZ4HC_CCtx_internal LZ4HC_CCtx_internal; | |
| struct LZ4HC_CCtx_internal | |
| { | |
| LZ4_u32 hashTable[LZ4HC_HASHTABLESIZE]; | |
| LZ4_u16 chainTable[LZ4HC_MAXD]; | |
| const LZ4_byte* end; /* next block here to continue on current prefix */ | |
| const LZ4_byte* prefixStart; /* Indexes relative to this position */ | |
| const LZ4_byte* dictStart; /* alternate reference for extDict */ | |
| LZ4_u32 dictLimit; /* below that point, need extDict */ | |
| LZ4_u32 lowLimit; /* below that point, no more history */ | |
| LZ4_u32 nextToUpdate; /* index from which to continue dictionary update */ | |
| short compressionLevel; | |
| LZ4_i8 favorDecSpeed; /* favor decompression speed if this flag set, | |
| otherwise, favor compression ratio */ | |
| LZ4_i8 dirty; /* stream has to be fully reset if this flag is set */ | |
| const LZ4HC_CCtx_internal* dictCtx; | |
| }; | |
| union LZ4_streamHC_u { | |
| char minStateSize[LZ4_STREAMHC_MINSIZE]; | |
| LZ4HC_CCtx_internal internal_donotuse; | |
| }; /* previously typedef'd to LZ4_streamHC_t */ | |
| /* LZ4_streamHC_t : | |
| * This structure allows static allocation of LZ4 HC streaming state. | |
| * This can be used to allocate statically on stack, or as part of a larger structure. | |
| * | |
| * Such state **must** be initialized using LZ4_initStreamHC() before first use. | |
| * | |
| * Note that invoking LZ4_initStreamHC() is not required when | |
| * the state was created using LZ4_createStreamHC() (which is recommended). | |
| * Using the normal builder, a newly created state is automatically initialized. | |
| * | |
| * Static allocation shall only be used in combination with static linking. | |
| */ | |
| /* LZ4_initStreamHC() : v1.9.0+ | |
| * Required before first use of a statically allocated LZ4_streamHC_t. | |
| * Before v1.9.0 : use LZ4_resetStreamHC() instead | |
| */ | |
| LZ4LIB_API LZ4_streamHC_t* LZ4_initStreamHC(void* buffer, size_t size); | |
| /*-************************************ | |
| * Deprecated Functions | |
| **************************************/ | |
| /* see lz4.h LZ4_DISABLE_DEPRECATE_WARNINGS to turn off deprecation warnings */ | |
| /* deprecated compression functions */ | |
| LZ4_DEPRECATED("use LZ4_compress_HC() instead") LZ4LIB_API int LZ4_compressHC (const char* source, char* dest, int inputSize); | |
| LZ4_DEPRECATED("use LZ4_compress_HC() instead") LZ4LIB_API int LZ4_compressHC_limitedOutput (const char* source, char* dest, int inputSize, int maxOutputSize); | |
| LZ4_DEPRECATED("use LZ4_compress_HC() instead") LZ4LIB_API int LZ4_compressHC2 (const char* source, char* dest, int inputSize, int compressionLevel); | |
| LZ4_DEPRECATED("use LZ4_compress_HC() instead") LZ4LIB_API int LZ4_compressHC2_limitedOutput(const char* source, char* dest, int inputSize, int maxOutputSize, int compressionLevel); | |
| LZ4_DEPRECATED("use LZ4_compress_HC_extStateHC() instead") LZ4LIB_API int LZ4_compressHC_withStateHC (void* state, const char* source, char* dest, int inputSize); | |
| LZ4_DEPRECATED("use LZ4_compress_HC_extStateHC() instead") LZ4LIB_API int LZ4_compressHC_limitedOutput_withStateHC (void* state, const char* source, char* dest, int inputSize, int maxOutputSize); | |
| LZ4_DEPRECATED("use LZ4_compress_HC_extStateHC() instead") LZ4LIB_API int LZ4_compressHC2_withStateHC (void* state, const char* source, char* dest, int inputSize, int compressionLevel); | |
| LZ4_DEPRECATED("use LZ4_compress_HC_extStateHC() instead") LZ4LIB_API int LZ4_compressHC2_limitedOutput_withStateHC(void* state, const char* source, char* dest, int inputSize, int maxOutputSize, int compressionLevel); | |
| LZ4_DEPRECATED("use LZ4_compress_HC_continue() instead") LZ4LIB_API int LZ4_compressHC_continue (LZ4_streamHC_t* LZ4_streamHCPtr, const char* source, char* dest, int inputSize); | |
| LZ4_DEPRECATED("use LZ4_compress_HC_continue() instead") LZ4LIB_API int LZ4_compressHC_limitedOutput_continue (LZ4_streamHC_t* LZ4_streamHCPtr, const char* source, char* dest, int inputSize, int maxOutputSize); | |
| /* Obsolete streaming functions; degraded functionality; do not use! | |
| * | |
| * In order to perform streaming compression, these functions depended on data | |
| * that is no longer tracked in the state. They have been preserved as well as | |
| * possible: using them will still produce a correct output. However, use of | |
| * LZ4_slideInputBufferHC() will truncate the history of the stream, rather | |
| * than preserve a window-sized chunk of history. | |
| */ | |
| LZ4_DEPRECATED("use LZ4_createStreamHC() instead") LZ4LIB_API void* LZ4_createHC (const char* inputBuffer); | |
| LZ4_DEPRECATED("use LZ4_freeStreamHC() instead") LZ4LIB_API int LZ4_freeHC (void* LZ4HC_Data); | |
| LZ4_DEPRECATED("use LZ4_saveDictHC() instead") LZ4LIB_API char* LZ4_slideInputBufferHC (void* LZ4HC_Data); | |
| LZ4_DEPRECATED("use LZ4_compress_HC_continue() instead") LZ4LIB_API int LZ4_compressHC2_continue (void* LZ4HC_Data, const char* source, char* dest, int inputSize, int compressionLevel); | |
| LZ4_DEPRECATED("use LZ4_compress_HC_continue() instead") LZ4LIB_API int LZ4_compressHC2_limitedOutput_continue (void* LZ4HC_Data, const char* source, char* dest, int inputSize, int maxOutputSize, int compressionLevel); | |
| LZ4_DEPRECATED("use LZ4_createStreamHC() instead") LZ4LIB_API int LZ4_sizeofStreamStateHC(void); | |
| LZ4_DEPRECATED("use LZ4_initStreamHC() instead") LZ4LIB_API int LZ4_resetStreamStateHC(void* state, char* inputBuffer); | |
| /* LZ4_resetStreamHC() is now replaced by LZ4_initStreamHC(). | |
| * The intention is to emphasize the difference with LZ4_resetStreamHC_fast(), | |
| * which is now the recommended function to start a new stream of blocks, | |
| * but cannot be used to initialize a memory segment containing arbitrary garbage data. | |
| * | |
| * It is recommended to switch to LZ4_initStreamHC(). | |
| * LZ4_resetStreamHC() will generate deprecation warnings in a future version. | |
| */ | |
| LZ4LIB_API void LZ4_resetStreamHC (LZ4_streamHC_t* streamHCPtr, int compressionLevel); | |
| } | |
| /*-************************************************** | |
| * !!!!! STATIC LINKING ONLY !!!!! | |
| * Following definitions are considered experimental. | |
| * They should not be linked from DLL, | |
| * as there is no guarantee of API stability yet. | |
| * Prototypes will be promoted to "stable" status | |
| * after successful usage in real-life scenarios. | |
| ***************************************************/ | |
| extern "C" { | |
| /*! LZ4_setCompressionLevel() : v1.8.0+ (experimental) | |
| * It's possible to change compression level | |
| * between successive invocations of LZ4_compress_HC_continue*() | |
| * for dynamic adaptation. | |
| */ | |
| LZ4LIB_STATIC_API void LZ4_setCompressionLevel( | |
| LZ4_streamHC_t* LZ4_streamHCPtr, int compressionLevel); | |
| /*! LZ4_favorDecompressionSpeed() : v1.8.2+ (experimental) | |
| * Opt. Parser will favor decompression speed over compression ratio. | |
| * Only applicable to levels >= LZ4HC_CLEVEL_OPT_MIN. | |
| */ | |
| LZ4LIB_STATIC_API void LZ4_favorDecompressionSpeed( | |
| LZ4_streamHC_t* LZ4_streamHCPtr, int favor); | |
| /*! LZ4_resetStreamHC_fast() : v1.9.0+ | |
| * When an LZ4_streamHC_t is known to be in a internally coherent state, | |
| * it can often be prepared for a new compression with almost no work, only | |
| * sometimes falling back to the full, expensive reset that is always required | |
| * when the stream is in an indeterminate state (i.e., the reset performed by | |
| * LZ4_resetStreamHC()). | |
| * | |
| * LZ4_streamHCs are guaranteed to be in a valid state when: | |
| * - returned from LZ4_createStreamHC() | |
| * - reset by LZ4_resetStreamHC() | |
| * - memset(stream, 0, sizeof(LZ4_streamHC_t)) | |
| * - the stream was in a valid state and was reset by LZ4_resetStreamHC_fast() | |
| * - the stream was in a valid state and was then used in any compression call | |
| * that returned success | |
| * - the stream was in an indeterminate state and was used in a compression | |
| * call that fully reset the state (LZ4_compress_HC_extStateHC()) and that | |
| * returned success | |
| * | |
| * Note: | |
| * A stream that was last used in a compression call that returned an error | |
| * may be passed to this function. However, it will be fully reset, which will | |
| * clear any existing history and settings from the context. | |
| */ | |
| LZ4LIB_STATIC_API void LZ4_resetStreamHC_fast( | |
| LZ4_streamHC_t* LZ4_streamHCPtr, int compressionLevel); | |
| /*! LZ4_compress_HC_extStateHC_fastReset() : | |
| * A variant of LZ4_compress_HC_extStateHC(). | |
| * | |
| * Using this variant avoids an expensive initialization step. It is only safe | |
| * to call if the state buffer is known to be correctly initialized already | |
| * (see above comment on LZ4_resetStreamHC_fast() for a definition of | |
| * "correctly initialized"). From a high level, the difference is that this | |
| * function initializes the provided state with a call to | |
| * LZ4_resetStreamHC_fast() while LZ4_compress_HC_extStateHC() starts with a | |
| * call to LZ4_resetStreamHC(). | |
| */ | |
| LZ4LIB_STATIC_API int LZ4_compress_HC_extStateHC_fastReset ( | |
| void* state, | |
| const char* src, char* dst, | |
| int srcSize, int dstCapacity, | |
| int compressionLevel); | |
| } | |
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