mirror of
https://github.com/astaxie/beego.git
synced 2024-11-30 03:41:29 +00:00
49 lines
832 B
Go
49 lines
832 B
Go
|
// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
|
||
|
|
// All rights reserved.
|
||
|
|
//
|
||
|
|
// Use of this source code is governed by a BSD-style license that can be
|
||
|
|
// found in the LICENSE file.
|
||
|
|
|
||
|
|
package util
|
||
|
|
|
||
|
|
import (
|
||
|
|
"encoding/binary"
|
||
|
|
)
|
||
|
|
|
||
|
|
// Hash return hash of the given data.
|
||
|
|
func Hash(data []byte, seed uint32) uint32 {
|
||
|
|
// Similar to murmur hash
|
||
|
|
const (
|
||
|
|
m = uint32(0xc6a4a793)
|
||
|
|
r = uint32(24)
|
||
|
|
)
|
||
|
|
var (
|
||
|
|
h = seed ^ (uint32(len(data)) * m)
|
||
|
|
i int
|
||
|
|
)
|
||
|
|
|
||
|
|
for n := len(data) - len(data)%4; i < n; i += 4 {
|
||
|
|
h += binary.LittleEndian.Uint32(data[i:])
|
||
|
|
h *= m
|
||
|
|
h ^= (h >> 16)
|
||
|
|
}
|
||
|
|
|
||
|
|
switch len(data) - i {
|
||
|
|
default:
|
||
|
|
panic("not reached")
|
||
|
|
case 3:
|
||
|
|
h += uint32(data[i+2]) << 16
|
||
|
|
fallthrough
|
||
|
|
case 2:
|
||
|
|
h += uint32(data[i+1]) << 8
|
||
|
|
fallthrough
|
||
|
|
case 1:
|
||
|
|
h += uint32(data[i])
|
||
|
|
h *= m
|
||
|
|
h ^= (h >> r)
|
||
|
|
case 0:
|
||
|
|
}
|
||
|
|
|
||
|
|
return h
|
||
|
|
}
|