134 lines
2.8 KiB
Go
134 lines
2.8 KiB
Go
// Copyright 2011 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// The fnv package implements FNV-1 and FNV-1a,
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// non-cryptographic hash functions created by
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// Glenn Fowler, Landon Curt Noll, and Phong Vo.
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// See http://isthe.com/chongo/tech/comp/fnv/.
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package fnv
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import (
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"encoding/binary"
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"hash"
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"os"
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"unsafe"
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)
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type (
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sum32 uint32
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sum32a uint32
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sum64 uint64
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sum64a uint64
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)
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const (
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offset32 = 2166136261
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offset64 = 14695981039346656037
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prime32 = 16777619
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prime64 = 1099511628211
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)
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// New32 returns a new 32-bit FNV-1 hash.Hash.
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func New32() hash.Hash32 {
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var s sum32 = offset32
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return &s
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}
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// New32a returns a new 32-bit FNV-1a hash.Hash.
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func New32a() hash.Hash32 {
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var s sum32a = offset32
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return &s
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}
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// New64 returns a new 64-bit FNV-1 hash.Hash.
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func New64() hash.Hash64 {
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var s sum64 = offset64
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return &s
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}
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// New64a returns a new 64-bit FNV-1a hash.Hash.
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func New64a() hash.Hash64 {
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var s sum64a = offset64
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return &s
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}
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func (s *sum32) Reset() { *s = offset32 }
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func (s *sum32a) Reset() { *s = offset32 }
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func (s *sum64) Reset() { *s = offset64 }
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func (s *sum64a) Reset() { *s = offset64 }
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func (s *sum32) Sum32() uint32 { return uint32(*s) }
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func (s *sum32a) Sum32() uint32 { return uint32(*s) }
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func (s *sum64) Sum64() uint64 { return uint64(*s) }
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func (s *sum64a) Sum64() uint64 { return uint64(*s) }
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func (s *sum32) Write(data []byte) (int, os.Error) {
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hash := *s
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for _, c := range data {
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hash *= prime32
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hash ^= sum32(c)
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}
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*s = hash
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return len(data), nil
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}
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func (s *sum32a) Write(data []byte) (int, os.Error) {
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hash := *s
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for _, c := range data {
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hash ^= sum32a(c)
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hash *= prime32
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}
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*s = hash
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return len(data), nil
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}
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func (s *sum64) Write(data []byte) (int, os.Error) {
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hash := *s
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for _, c := range data {
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hash *= prime64
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hash ^= sum64(c)
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}
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*s = hash
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return len(data), nil
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}
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func (s *sum64a) Write(data []byte) (int, os.Error) {
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hash := *s
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for _, c := range data {
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hash ^= sum64a(c)
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hash *= prime64
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}
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*s = hash
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return len(data), nil
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}
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func (s *sum32) Size() int { return unsafe.Sizeof(*s) }
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func (s *sum32a) Size() int { return unsafe.Sizeof(*s) }
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func (s *sum64) Size() int { return unsafe.Sizeof(*s) }
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func (s *sum64a) Size() int { return unsafe.Sizeof(*s) }
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func (s *sum32) Sum() []byte {
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a := make([]byte, unsafe.Sizeof(*s))
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binary.BigEndian.PutUint32(a, uint32(*s))
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return a
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}
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func (s *sum32a) Sum() []byte {
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a := make([]byte, unsafe.Sizeof(*s))
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binary.BigEndian.PutUint32(a, uint32(*s))
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return a
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}
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func (s *sum64) Sum() []byte {
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a := make([]byte, unsafe.Sizeof(*s))
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binary.BigEndian.PutUint64(a, uint64(*s))
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return a
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}
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func (s *sum64a) Sum() []byte {
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a := make([]byte, unsafe.Sizeof(*s))
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binary.BigEndian.PutUint64(a, uint64(*s))
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return a
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}
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