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