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// 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
}
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