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Diffstat (limited to 'vendor/github.com/pierrec/lz4/lz4.go')
-rw-r--r-- | vendor/github.com/pierrec/lz4/lz4.go | 68 |
1 files changed, 0 insertions, 68 deletions
diff --git a/vendor/github.com/pierrec/lz4/lz4.go b/vendor/github.com/pierrec/lz4/lz4.go deleted file mode 100644 index 35802756c..000000000 --- a/vendor/github.com/pierrec/lz4/lz4.go +++ /dev/null @@ -1,68 +0,0 @@ -// Package lz4 implements reading and writing lz4 compressed data (a frame), -// as specified in http://fastcompression.blogspot.fr/2013/04/lz4-streaming-format-final.html. -// -// Although the block level compression and decompression functions are exposed and are fully compatible -// with the lz4 block format definition, they are low level and should not be used directly. -// For a complete description of an lz4 compressed block, see: -// http://fastcompression.blogspot.fr/2011/05/lz4-explained.html -// -// See https://github.com/Cyan4973/lz4 for the reference C implementation. -// -package lz4 - -const ( - // Extension is the LZ4 frame file name extension - Extension = ".lz4" - // Version is the LZ4 frame format version - Version = 1 - - frameMagic uint32 = 0x184D2204 - frameSkipMagic uint32 = 0x184D2A50 - - // The following constants are used to setup the compression algorithm. - minMatch = 4 // the minimum size of the match sequence size (4 bytes) - winSizeLog = 16 // LZ4 64Kb window size limit - winSize = 1 << winSizeLog - winMask = winSize - 1 // 64Kb window of previous data for dependent blocks - compressedBlockFlag = 1 << 31 - compressedBlockMask = compressedBlockFlag - 1 - - // hashLog determines the size of the hash table used to quickly find a previous match position. - // Its value influences the compression speed and memory usage, the lower the faster, - // but at the expense of the compression ratio. - // 16 seems to be the best compromise. - hashLog = 16 - hashTableSize = 1 << hashLog - hashShift = uint((minMatch * 8) - hashLog) - - mfLimit = 8 + minMatch // The last match cannot start within the last 12 bytes. - skipStrength = 6 // variable step for fast scan -) - -// map the block max size id with its value in bytes: 64Kb, 256Kb, 1Mb and 4Mb. -var ( - bsMapID = map[byte]int{4: 64 << 10, 5: 256 << 10, 6: 1 << 20, 7: 4 << 20} - bsMapValue = make(map[int]byte, len(bsMapID)) -) - -// Reversed. -func init() { - for i, v := range bsMapID { - bsMapValue[v] = i - } -} - -// Header describes the various flags that can be set on a Writer or obtained from a Reader. -// The default values match those of the LZ4 frame format definition -// (http://fastcompression.blogspot.com/2013/04/lz4-streaming-format-final.html). -// -// NB. in a Reader, in case of concatenated frames, the Header values may change between Read() calls. -// It is the caller responsibility to check them if necessary. -type Header struct { - BlockChecksum bool // Compressed blocks checksum flag. - NoChecksum bool // Frame checksum flag. - BlockMaxSize int // Size of the uncompressed data block (one of [64KB, 256KB, 1MB, 4MB]). Default=4MB. - Size uint64 // Frame total size. It is _not_ computed by the Writer. - CompressionLevel int // Compression level (higher is better, use 0 for fastest compression). - done bool // Header processed flag (Read or Write and checked). -} |