diff options
Diffstat (limited to 'lib/lz4frame.c')
| -rw-r--r-- | lib/lz4frame.c | 49 |
1 files changed, 19 insertions, 30 deletions
diff --git a/lib/lz4frame.c b/lib/lz4frame.c index d08cf94..ed47c0a 100644 --- a/lib/lz4frame.c +++ b/lib/lz4frame.c @@ -208,6 +208,21 @@ static BYTE LZ4F_headerChecksum (const BYTE* header, size_t length) /************************************** * Simple compression functions **************************************/ +static blockSizeID_t LZ4F_optimalBSID(const blockSizeID_t requestedBSID, const size_t srcSize) +{ + blockSizeID_t proposedBSID = max64KB; + size_t maxBlockSize = 64 KB; + while (requestedBSID > proposedBSID) + { + if (srcSize <= maxBlockSize) + return proposedBSID; + proposedBSID = (blockSizeID_t)((int)proposedBSID + 1); + maxBlockSize <<= 2; + } + return requestedBSID; +} + + size_t LZ4F_compressFrameBound(size_t srcSize, const LZ4F_preferences_t* preferencesPtr) { LZ4F_preferences_t prefs; @@ -217,20 +232,7 @@ size_t LZ4F_compressFrameBound(size_t srcSize, const LZ4F_preferences_t* prefere if (preferencesPtr!=NULL) prefs = *preferencesPtr; else memset(&prefs, 0, sizeof(prefs)); - { - blockSizeID_t proposedBSID = max64KB; - size_t maxBlockSize = 64 KB; - while (prefs.frameInfo.blockSizeID > proposedBSID) - { - if (srcSize <= maxBlockSize) - { - prefs.frameInfo.blockSizeID = proposedBSID; - break; - } - proposedBSID = (blockSizeID_t)( ((int)proposedBSID) + 1); - maxBlockSize <<= 2; - } - } + prefs.frameInfo.blockSizeID = LZ4F_optimalBSID(prefs.frameInfo.blockSizeID, srcSize); prefs.autoFlush = 1; headerSize = 7; /* basic header size (no option) including magic number */ @@ -241,11 +243,11 @@ size_t LZ4F_compressFrameBound(size_t srcSize, const LZ4F_preferences_t* prefere /* LZ4F_compressFrame() -* Compress an entire srcBuffer into a valid LZ4 frame, as defined by specification v1.4.1, in a single step. +* Compress an entire srcBuffer into a valid LZ4 frame, as defined by specification v1.5.0, in a single step. * The most important rule is that dstBuffer MUST be large enough (dstMaxSize) to ensure compression completion even in worst case. * You can get the minimum value of dstMaxSize by using LZ4F_compressFrameBound() * If this condition is not respected, LZ4F_compressFrame() will fail (result is an errorCode) -* The LZ4F_preferences_t structure is optional : you can provide NULL as argument. All preferences will be set to default. +* The LZ4F_preferences_t structure is optional : you can provide NULL as argument. All preferences will then be set to default. * The result of the function is the number of bytes written into dstBuffer. * The function outputs an error code if it fails (can be tested using LZ4F_isError()) */ @@ -268,20 +270,7 @@ size_t LZ4F_compressFrame(void* dstBuffer, size_t dstMaxSize, const void* srcBuf if (preferencesPtr!=NULL) prefs = *preferencesPtr; else memset(&prefs, 0, sizeof(prefs)); - { - blockSizeID_t proposedBSID = max64KB; - size_t maxBlockSize = 64 KB; - while (prefs.frameInfo.blockSizeID > proposedBSID) - { - if (srcSize <= maxBlockSize) - { - prefs.frameInfo.blockSizeID = proposedBSID; - break; - } - proposedBSID = (blockSizeID_t)((int)proposedBSID + 1); - maxBlockSize <<= 2; - } - } + prefs.frameInfo.blockSizeID = LZ4F_optimalBSID(prefs.frameInfo.blockSizeID, srcSize); prefs.autoFlush = 1; if (srcSize <= LZ4F_getBlockSize(prefs.frameInfo.blockSizeID)) prefs.frameInfo.blockMode = blockIndependent; /* no need for linked blocks */ |