seaweedfs/go/storage/crc.go

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package storage
import (
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"code.google.com/p/weed-fs/go/util"
"fmt"
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"hash/crc32"
)
var table = crc32.MakeTable(crc32.Castagnoli)
type CRC uint32
func NewCRC(b []byte) CRC {
return CRC(0).Update(b)
}
func (c CRC) Update(b []byte) CRC {
return CRC(crc32.Update(uint32(c), table, b))
}
func (c CRC) Value() uint32 {
return uint32(c>>15|c<<17) + 0xa282ead8
}
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func (n *Needle) Etag() string {
bits := make([]byte, 4)
util.Uint32toBytes(bits, uint32(n.Checksum))
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return fmt.Sprintf("\"%x\"", bits)
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}