diff options
Diffstat (limited to 'lib/lz4.h')
| -rw-r--r-- | lib/lz4.h | 207 |
1 files changed, 126 insertions, 81 deletions
@@ -39,16 +39,16 @@ extern "C" { #endif /* - * lz4.h provides block compression functions, for optimal performance. + * lz4.h provides block compression functions, and gives full buffer control to programmer. * If you need to generate inter-operable compressed data (respecting LZ4 frame specification), - * please use lz4frame.h instead. + * and can let the library handle its own memory, please use lz4frame.h instead. */ /************************************** * Version **************************************/ #define LZ4_VERSION_MAJOR 1 /* for breaking interface changes */ -#define LZ4_VERSION_MINOR 6 /* for new (non-breaking) interface capabilities */ +#define LZ4_VERSION_MINOR 7 /* for new (non-breaking) interface capabilities */ #define LZ4_VERSION_RELEASE 0 /* for tweaks, bug-fixes, or development */ #define LZ4_VERSION_NUMBER (LZ4_VERSION_MAJOR *100*100 + LZ4_VERSION_MINOR *100 + LZ4_VERSION_RELEASE) int LZ4_versionNumber (void); @@ -70,28 +70,32 @@ int LZ4_versionNumber (void); * Simple Functions **************************************/ -int LZ4_compress (const char* source, char* dest, int sourceSize); +int LZ4_compress_default(const char* source, char* dest, int sourceSize, int maxDestSize); int LZ4_decompress_safe (const char* source, char* dest, int compressedSize, int maxDecompressedSize); /* -LZ4_compress() : - Compresses 'sourceSize' 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_SIZE - return : the number of bytes written in buffer dest - or 0 if the compression fails +LZ4_compress_default() : + Compresses 'sourceSize' bytes from buffer 'source' + into already allocated 'dest' buffer of size 'maxDestSize'. + Compression is guaranteed to succeed if 'maxDestSize' >= LZ4_compressBound(sourceSize). + It also runs faster, so it's a recommended setting. + If the function cannot compress 'source' into a more limited 'dest' budget, + compression stops *immediately*, and the function result is zero. + As a consequence, 'dest' content is not valid. + This function never writes outside 'dest' buffer, nor read outside 'source' buffer. + sourceSize : Max supported value is LZ4_MAX_INPUT_VALUE + maxDestSize : full or partial size of buffer 'dest' (which must be already allocated) + return : the number of bytes written into buffer 'dest' (necessarily <= maxOutputSize) + or 0 if compression fails LZ4_decompress_safe() : - compressedSize : is obviously the source size - maxDecompressedSize : is the size of the destination buffer, which must be already allocated. - return : the number of bytes decompressed into the destination buffer (necessarily <= maxDecompressedSize) - If the destination buffer is not large enough, decoding will stop and output an error code (<0). + compressedSize : is the precise full size of the compressed block. + maxDecompressedSize : is the size of destination buffer, which must be already allocated. + return : the number of bytes decompressed into destination buffer (necessarily <= maxDecompressedSize) + If 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, - and never writes outside of output buffer, nor reads outside of input buffer. - It is also protected against malicious data packets. + This function is protected against buffer overflow exploits, including malicious data packets. + It never writes outside output buffer, nor reads outside input buffer. */ @@ -99,45 +103,55 @@ LZ4_decompress_safe() : * 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) +#define LZ4_COMPRESSBOUND(isize) ((unsigned)(isize) > (unsigned)LZ4_MAX_INPUT_SIZE ? 0 : (isize) + ((isize)/255) + 16) /* LZ4_compressBound() : Provides the maximum size that LZ4 compression may output in a "worst case" scenario (input data not compressible) - This function is primarily useful for memory allocation purposes (output buffer size). + This function is primarily useful for memory allocation purposes (destination buffer size). Macro LZ4_COMPRESSBOUND() is also provided for compilation-time evaluation (stack memory allocation for example). - - 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) + Note that LZ4_compress_default() compress faster when dest buffer size is >= LZ4_compressBound(srcSize) + inputSize : 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); - +int LZ4_compressBound(int inputSize); /* -LZ4_compress_limitedOutput() : - Compress 'sourceSize' 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 saves time and memory on detecting non-compressible (or barely compressible) data. - This function never writes outside of provided output buffer. - - sourceSize : 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 compression fails +LZ4_compress_fast() : + Same as LZ4_compress_default(), but allows to select an "acceleration" factor. + The larger the acceleration value, the faster the algorithm, but also the lesser the compression. + It's a trade-off. It can be fine tuned, with each successive value providing roughly +~3% to speed. + An acceleration value of "0" means "use Default value" (see lz4.c) + An acceleration value of "1" is the same as regular LZ4_compress_default() */ -int LZ4_compress_limitedOutput (const char* source, char* dest, int sourceSize, int maxOutputSize); +int LZ4_compress_fast (const char* source, char* dest, int sourceSize, int maxDestSize, int acceleration); /* -LZ4_compress_withState() : - Same compression functions, but using an externally allocated memory space to store compression state. +LZ4_compress_fast_extState() : + Same compression function, just using an externally allocated memory space to store compression state. Use LZ4_sizeofState() to know how much memory must be allocated, - and then, provide it as 'void* state' to compression functions. + and allocate it on 8-bytes boundaries (using malloc() typically). + Then, provide it as 'void* state' to compression function. */ int LZ4_sizeofState(void); -int LZ4_compress_withState (void* state, const char* source, char* dest, int inputSize); -int LZ4_compress_limitedOutput_withState (void* state, const char* source, char* dest, int inputSize, int maxOutputSize); +int LZ4_compress_fast_extState (void* state, const char* source, char* dest, int inputSize, int maxDestSize, int acceleration); + + +/* +LZ4_compress_destSize() : + Reverse the logic, by compressing as much data as possible from 'source' buffer + into already allocated buffer 'dest' of size 'targetDestSize'. + This function either compresses the entire 'source' content into 'dest' if it's large enough, + or fill 'dest' buffer completely with as much data as possible from 'source'. + Original idea by WiredTiger team. + *sourceSizePtr : will be modified to indicate how many bytes where read from 'source' to fill 'dest'. + New value is necessarily <= old value. + return : Nb bytes written into 'dest' (necessarily <= targetDestSize) + or 0 if compression fails +*/ +int LZ4_compress_destSize (const char* source, char* dest, int* sourceSizePtr, int targetDestSize); /* @@ -153,7 +167,6 @@ LZ4_decompress_fast() : */ 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' @@ -172,7 +185,6 @@ int LZ4_decompress_safe_partial (const char* source, char* dest, int compressedS /*********************************************** * Streaming Compression Functions ***********************************************/ - #define LZ4_STREAMSIZE_U64 ((1 << (LZ4_MEMORY_USAGE-3)) + 4) #define LZ4_STREAMSIZE (LZ4_STREAMSIZE_U64 * sizeof(long long)) /* @@ -188,7 +200,7 @@ typedef struct { long long table[LZ4_STREAMSIZE_U64]; } LZ4_stream_t; * LZ4_resetStream * Use this function to init an allocated LZ4_stream_t structure */ -void LZ4_resetStream (LZ4_stream_t* LZ4_streamPtr); +void LZ4_resetStream (LZ4_stream_t* streamPtr); /* * LZ4_createStream will allocate and initialize an LZ4_stream_t structure @@ -197,7 +209,7 @@ void LZ4_resetStream (LZ4_stream_t* LZ4_streamPtr); * They are more future proof, in case of a change of LZ4_stream_t size. */ LZ4_stream_t* LZ4_createStream(void); -int LZ4_freeStream (LZ4_stream_t* LZ4_streamPtr); +int LZ4_freeStream (LZ4_stream_t* streamPtr); /* * LZ4_loadDict @@ -206,32 +218,27 @@ int LZ4_freeStream (LZ4_stream_t* LZ4_streamPtr); * Loading a size of 0 is allowed. * Return : dictionary size, in bytes (necessarily <= 64 KB) */ -int LZ4_loadDict (LZ4_stream_t* LZ4_streamPtr, const char* dictionary, int dictSize); +int LZ4_loadDict (LZ4_stream_t* streamPtr, 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. - * dest buffer must be already allocated, and sized to at least LZ4_compressBound(inputSize) + * LZ4_compress_fast_continue + * Compress buffer content 'src', using data from previously compressed blocks as dictionary to improve compression ratio. + * Important : Previous data blocks are assumed to still be present and unmodified ! + * 'dst' buffer must be already allocated. + * If maxDstSize >= LZ4_compressBound(srcSize), compression is guaranteed to succeed, and runs faster. + * If not, and if compressed data cannot fit into 'dst' buffer size, compression stops, and function returns a zero. */ -int LZ4_compress_continue (LZ4_stream_t* LZ4_streamPtr, 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 (LZ4_stream_t* LZ4_streamPtr, const char* source, char* dest, int inputSize, int maxOutputSize); +int LZ4_compress_fast_continue (LZ4_stream_t* streamPtr, const char* src, char* dst, int srcSize, int maxDstSize, int acceleration); /* * LZ4_saveDict * If previously compressed data block is not guaranteed to remain available at its memory location * save it into a safer 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() + * dictionary is immediately usable, you can therefore call LZ4_compress_fast_continue() * Return : saved dictionary size in bytes (necessarily <= dictSize), or 0 if error */ -int LZ4_saveDict (LZ4_stream_t* LZ4_streamPtr, char* safeBuffer, int dictSize); +int LZ4_saveDict (LZ4_stream_t* streamPtr, char* safeBuffer, int dictSize); /************************************************ @@ -266,8 +273,18 @@ int LZ4_setStreamDecode (LZ4_streamDecode_t* LZ4_streamDecode, const char* dicti *_continue() : These decoding functions allow decompression of multiple blocks in "streaming" mode. Previously decoded blocks *must* remain available at the memory position where they were decoded (up to 64 KB) - If this condition is not possible, save the relevant part of decoded data into a safe buffer, - and indicate where is its new address using LZ4_setStreamDecode() + In the case of a ring buffers, decoding buffer must be either : + - Exactly same size as encoding buffer, with same update rule (block boundaries at same positions) + In which case, the decoding & encoding ring buffer can have any size, including very small ones ( < 64 KB). + - Larger than encoding buffer, by a minimum of maxBlockSize more bytes. + maxBlockSize is implementation dependent. It's the maximum size you intend to compress into a single block. + In which case, encoding and decoding buffers do not need to be synchronized, + and encoding ring buffer can have any size, including small ones ( < 64 KB). + - _At least_ 64 KB + 8 bytes + maxBlockSize. + In which case, encoding and decoding buffers do not need to be synchronized, + and encoding ring buffer can have any size, including larger than decoding buffer. + Whenever these conditions are not possible, save the last 64KB of decoded data into a safe buffer, + and indicate where it is saved using LZ4_setStreamDecode() */ int LZ4_decompress_safe_continue (LZ4_streamDecode_t* LZ4_streamDecode, const char* source, char* dest, int compressedSize, int maxDecompressedSize); int LZ4_decompress_fast_continue (LZ4_streamDecode_t* LZ4_streamDecode, const char* source, char* dest, int originalSize); @@ -277,8 +294,8 @@ int LZ4_decompress_fast_continue (LZ4_streamDecode_t* LZ4_streamDecode, const ch Advanced decoding functions : *_usingDict() : These decoding functions work the same as - a combination of LZ4_setDictDecode() followed by LZ4_decompress_x_continue() - They are stand-alone and don't use nor update an LZ4_streamDecode_t structure. + a combination of LZ4_setStreamDecode() followed by LZ4_decompress_x_continue() + They are stand-alone. They don't need nor update an LZ4_streamDecode_t structure. */ int LZ4_decompress_safe_usingDict (const char* source, char* dest, int compressedSize, int maxDecompressedSize, const char* dictStart, int dictSize); int LZ4_decompress_fast_usingDict (const char* source, char* dest, int originalSize, const char* dictStart, int dictSize); @@ -288,27 +305,55 @@ int LZ4_decompress_fast_usingDict (const char* source, char* dest, int originalS /************************************** * Obsolete Functions **************************************/ -/* -Obsolete decompression functions -These function names are deprecated and should no longer be used. -They are only provided here for compatibility with older user programs. -- LZ4_uncompress is the same as LZ4_decompress_fast -- LZ4_uncompress_unknownOutputSize is the same as LZ4_decompress_safe -These function prototypes are now disabled; uncomment them if you really need them. -It is highly recommended to stop using these functions and migrate to newer ones */ +/* Deprecate Warnings */ +/* Should these warnings messages be a problem, + it is generally possible to disable them, + with -Wno-deprecated-declarations for gcc + or _CRT_SECURE_NO_WARNINGS in Visual for example. + You can also define LZ4_DEPRECATE_WARNING_DEFBLOCK. */ +#ifndef LZ4_DEPRECATE_WARNING_DEFBLOCK +# define LZ4_DEPRECATE_WARNING_DEFBLOCK +# define LZ4_GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__) +# if (LZ4_GCC_VERSION >= 405) || defined(__clang__) +# define LZ4_DEPRECATED(message) __attribute__((deprecated(message))) +# elif (LZ4_GCC_VERSION >= 301) +# define LZ4_DEPRECATED(message) __attribute__((deprecated)) +# elif defined(_MSC_VER) +# define LZ4_DEPRECATED(message) __declspec(deprecated(message)) +# else +# pragma message("WARNING: You need to implement LZ4_DEPRECATED for this compiler") +# define LZ4_DEPRECATED(message) +# endif +#endif /* LZ4_DEPRECATE_WARNING_DEFBLOCK */ + +/* Obsolete compression functions */ +/* These functions are planned to start generate warnings by r131 approximately */ +int LZ4_compress (const char* source, char* dest, int sourceSize); +int LZ4_compress_limitedOutput (const char* source, char* dest, int sourceSize, int maxOutputSize); +int LZ4_compress_withState (void* state, const char* source, char* dest, int inputSize); +int LZ4_compress_limitedOutput_withState (void* state, const char* source, char* dest, int inputSize, int maxOutputSize); +int LZ4_compress_continue (LZ4_stream_t* LZ4_streamPtr, const char* source, char* dest, int inputSize); +int LZ4_compress_limitedOutput_continue (LZ4_stream_t* LZ4_streamPtr, const char* source, char* dest, int inputSize, int maxOutputSize); + +/* Obsolete decompression functions */ +/* These function names are completely deprecated and must no longer be used. + They are only provided here for compatibility with older programs. + - LZ4_uncompress is the same as LZ4_decompress_fast + - LZ4_uncompress_unknownOutputSize is the same as LZ4_decompress_safe + These function prototypes are now disabled; uncomment them only if you really need them. + It is highly recommended to stop using these prototypes and migrate to maintained ones */ /* int LZ4_uncompress (const char* source, char* dest, int outputSize); */ /* int LZ4_uncompress_unknownOutputSize (const char* source, char* dest, int isize, int maxOutputSize); */ - /* Obsolete streaming functions; use new streaming interface whenever possible */ -void* LZ4_create (const char* inputBuffer); -int LZ4_sizeofStreamState(void); -int LZ4_resetStreamState(void* state, const char* inputBuffer); -char* LZ4_slideInputBuffer (void* state); +LZ4_DEPRECATED("use LZ4_createStream() instead") void* LZ4_create (char* inputBuffer); +LZ4_DEPRECATED("use LZ4_createStream() instead") int LZ4_sizeofStreamState(void); +LZ4_DEPRECATED("use LZ4_resetStream() instead") int LZ4_resetStreamState(void* state, char* inputBuffer); +LZ4_DEPRECATED("use LZ4_saveDict() instead") char* LZ4_slideInputBuffer (void* state); /* Obsolete streaming decoding functions */ -int LZ4_decompress_safe_withPrefix64k (const char* source, char* dest, int compressedSize, int maxOutputSize); -int LZ4_decompress_fast_withPrefix64k (const char* source, char* dest, int originalSize); +LZ4_DEPRECATED("use LZ4_decompress_safe_usingDict() instead") int LZ4_decompress_safe_withPrefix64k (const char* src, char* dst, int compressedSize, int maxDstSize); +LZ4_DEPRECATED("use LZ4_decompress_fast_usingDict() instead") int LZ4_decompress_fast_withPrefix64k (const char* src, char* dst, int originalSize); #if defined (__cplusplus) |