diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/lz4frame.h | 27 | ||||
| -rw-r--r-- | lib/lz4hc.c | 12 |
2 files changed, 21 insertions, 18 deletions
diff --git a/lib/lz4frame.h b/lib/lz4frame.h index 7184cc3..48fbf80 100644 --- a/lib/lz4frame.h +++ b/lib/lz4frame.h @@ -207,6 +207,7 @@ typedef struct { unsigned reserved[3]; } LZ4F_decompressOptions_t; + /* Resource management */ LZ4F_errorCode_t LZ4F_createDecompressionContext(LZ4F_decompressionContext_t* ctxPtr, unsigned version); @@ -220,6 +221,7 @@ LZ4F_errorCode_t LZ4F_freeDecompressionContext(LZ4F_decompressionContext_t ctx); * Object can release its memory using LZ4F_freeDecompressionContext(); */ + /* Decompression */ size_t LZ4F_getFrameInfo(LZ4F_decompressionContext_t ctx, @@ -232,7 +234,7 @@ size_t LZ4F_getFrameInfo(LZ4F_decompressionContext_t ctx, * LZ4F_getFrameInfo() can also be used *after* starting decompression, on a valid LZ4F_decompressionContext_t. * The number of bytes read from srcBuffer will be provided within *srcSizePtr (necessarily <= original value). * You are expected to resume decompression from where it stopped (srcBuffer + *srcSizePtr) - * The function result is an hint of the better srcSize to use for next call to LZ4F_decompress, + * The function result is an hint of how many srcSize bytes LZ4F_decompress() expects for next call, * or an error code which can be tested using LZ4F_isError(). */ @@ -246,20 +248,21 @@ size_t LZ4F_decompress(LZ4F_decompressionContext_t ctx, * * The number of bytes regenerated into dstBuffer will be provided within *dstSizePtr (necessarily <= original value). * - * The number of bytes effectively used from srcBuffer will be provided within *srcSizePtr (necessarily <= original value). - * If the number of bytes read is < number of bytes provided, then the decompression operation is not complete. - * This typically happens when dstBuffer is not large enough to contain all decoded data. - * LZ4F_decompress() will have to be called again, starting from where it stopped (srcBuffer + *srcSizePtr) + * The number of bytes read from srcBuffer will be provided within *srcSizePtr (necessarily <= original value). + * If number of bytes read is < number of bytes provided, then decompression operation is not completed. + * It typically happens when dstBuffer is not large enough to contain all decoded data. + * LZ4F_decompress() must be called again, starting from where it stopped (srcBuffer + *srcSizePtr) * The function will check this condition, and refuse to continue if it is not respected. - * dstBuffer is supposed to be flushed between calls to the function, since its content will be rewritten. - * Different dst arguments can be used between each calls. * - * The function result is an hint of the better srcSize to use for next call to LZ4F_decompress. - * Basically, it's the size of the current (or remaining) compressed block + header of next block. - * Respecting the hint provides some boost to performance, since it does not need intermediate buffers. + * dstBuffer is supposed to be flushed between each call to the function, since its content will be overwritten. + * dst arguments can be changed at will with each consecutive call to the function. + * + * The function result is an hint of how many srcSize bytes LZ4F_decompress() expects for next call. + * Schematically, it's the size of the current (or remaining) compressed block + header of next block. + * Respecting the hint provides some boost to performance, since it does skip intermediate buffers. * This is just a hint, you can always provide any srcSize you want. - * When a frame is fully decoded, the function result will be 0. - * If decompression failed, function result is an error code which can be tested using LZ4F_isError(). + * When a frame is fully decoded, the function result will be 0. (no more data expected) + * If decompression failed, function result is an error code, which can be tested using LZ4F_isError(). */ diff --git a/lib/lz4hc.c b/lib/lz4hc.c index 6690e81..45f1208 100644 --- a/lib/lz4hc.c +++ b/lib/lz4hc.c @@ -36,13 +36,12 @@ You can contact the author at : /************************************** Tuning Parameter **************************************/ -#define LZ4HC_DEFAULT_COMPRESSIONLEVEL 8 +static const int LZ4HC_compressionLevel_default = 8; /************************************** Includes **************************************/ -#include "lz4.h" #include "lz4hc.h" @@ -82,6 +81,8 @@ You can contact the author at : #define OPTIMAL_ML (int)((ML_MASK-1)+MINMATCH) +static const int g_maxCompressionLevel = 16; + /************************************** Local Types @@ -328,7 +329,6 @@ FORCE_INLINE int LZ4HC_encodeSequence ( } -#define MAX_COMPRESSION_LEVEL 16 static int LZ4HC_compress_generic ( void* ctxvoid, const char* source, @@ -361,9 +361,9 @@ static int LZ4HC_compress_generic ( /* init */ - if (compressionLevel > MAX_COMPRESSION_LEVEL) compressionLevel = MAX_COMPRESSION_LEVEL; - if (compressionLevel == 0) compressionLevel = LZ4HC_DEFAULT_COMPRESSIONLEVEL; - maxNbAttempts = 1 << compressionLevel; + if (compressionLevel > g_maxCompressionLevel) compressionLevel = g_maxCompressionLevel; + if (compressionLevel < 1) compressionLevel = LZ4HC_compressionLevel_default; + maxNbAttempts = 1 << (compressionLevel-1); ctx->end += inputSize; ip++; |