seaweedfs/go/storage/crc.go
2016-04-09 14:38:01 +08:00

31 lines
516 B
Go

package storage
import (
"encoding/binary"
"fmt"
"github.com/klauspost/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
}
func (n *Needle) Etag() string {
bits := make([]byte, 4)
binary.BigEndian.PutUint32(bits, uint32(n.Checksum))
return fmt.Sprintf("\"%x\"", bits)
}