status-go/vendor/github.com/spaolacci/murmur3/murmur64.go

58 lines
1.5 KiB
Go

package murmur3
import (
"hash"
)
// Make sure interfaces are correctly implemented.
var (
_ hash.Hash = new(digest64)
_ hash.Hash64 = new(digest64)
_ bmixer = new(digest64)
)
// digest64 is half a digest128.
type digest64 digest128
// New64 returns a 64-bit hasher
func New64() hash.Hash64 { return New64WithSeed(0) }
// New64WithSeed returns a 64-bit hasher set with explicit seed value
func New64WithSeed(seed uint32) hash.Hash64 {
d := (*digest64)(New128WithSeed(seed).(*digest128))
return d
}
func (d *digest64) Sum(b []byte) []byte {
h1 := d.Sum64()
return append(b,
byte(h1>>56), byte(h1>>48), byte(h1>>40), byte(h1>>32),
byte(h1>>24), byte(h1>>16), byte(h1>>8), byte(h1))
}
func (d *digest64) Sum64() uint64 {
h1, _ := (*digest128)(d).Sum128()
return h1
}
// Sum64 returns the MurmurHash3 sum of data. It is equivalent to the
// following sequence (without the extra burden and the extra allocation):
// hasher := New64()
// hasher.Write(data)
// return hasher.Sum64()
func Sum64(data []byte) uint64 { return Sum64WithSeed(data, 0) }
// Sum64WithSeed returns the MurmurHash3 sum of data. It is equivalent to the
// following sequence (without the extra burden and the extra allocation):
// hasher := New64WithSeed(seed)
// hasher.Write(data)
// return hasher.Sum64()
func Sum64WithSeed(data []byte, seed uint32) uint64 {
d := &digest128{h1: uint64(seed), h2: uint64(seed)}
d.seed = seed
d.tail = d.bmix(data)
d.clen = len(data)
h1, _ := d.Sum128()
return h1
}