diff options
Diffstat (limited to 'lz4hc.h')
| -rw-r--r-- | lz4hc.h | 62 |
1 files changed, 56 insertions, 6 deletions
@@ -74,7 +74,7 @@ int LZ4_compressHC2_limitedOutput (const char* source, char* dest, int inputSize */ /* Note : -Decompression functions are provided within LZ4 source code (see "lz4.h") (BSD license) + Decompression functions are provided within LZ4 source code (see "lz4.h") (BSD license) */ @@ -95,19 +95,69 @@ 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 compressions functions using 'void* state' parameter. +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 area instead of allocating their own (on stack, or on heap). +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_U32 65548 +#define LZ4_STREAMHCSIZE (LZ4_STREAMHCSIZE_U32 * sizeof(unsigned int)) +typedef struct { unsigned int table[LZ4_STREAMHCSIZE_U32]; } 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(). +*/ + + + /************************************** - Streaming Functions + 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); +//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); |