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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package fnv implements FNV-1 and FNV-1a, non-cryptographic hash functions
// created by Glenn Fowler, Landon Curt Noll, and Phong Vo.
// See
// http://en.wikipedia.org/wiki/Fowler%E2%80%93Noll%E2%80%93Vo_hash_function.
package fnv
import (
"hash"
)
type (
sum32 uint32
sum32a uint32
sum64 uint64
sum64a uint64
)
const (
offset32 = 2166136261
offset64 = 14695981039346656037
prime32 = 16777619
prime64 = 1099511628211
)
// New32 returns a new 32-bit FNV-1 hash.Hash.
func New32() hash.Hash32 {
var s sum32 = offset32
return &s
}
// New32a returns a new 32-bit FNV-1a hash.Hash.
func New32a() hash.Hash32 {
var s sum32a = offset32
return &s
}
// New64 returns a new 64-bit FNV-1 hash.Hash.
func New64() hash.Hash64 {
var s sum64 = offset64
return &s
}
// New64a returns a new 64-bit FNV-1a hash.Hash.
func New64a() hash.Hash64 {
var s sum64a = offset64
return &s
}
func (s *sum32) Reset() { *s = offset32 }
func (s *sum32a) Reset() { *s = offset32 }
func (s *sum64) Reset() { *s = offset64 }
func (s *sum64a) Reset() { *s = offset64 }
func (s *sum32) Sum32() uint32 { return uint32(*s) }
func (s *sum32a) Sum32() uint32 { return uint32(*s) }
func (s *sum64) Sum64() uint64 { return uint64(*s) }
func (s *sum64a) Sum64() uint64 { return uint64(*s) }
func (s *sum32) Write(data []byte) (int, error) {
hash := *s
for _, c := range data {
hash *= prime32
hash ^= sum32(c)
}
*s = hash
return len(data), nil
}
func (s *sum32a) Write(data []byte) (int, error) {
hash := *s
for _, c := range data {
hash ^= sum32a(c)
hash *= prime32
}
*s = hash
return len(data), nil
}
func (s *sum64) Write(data []byte) (int, error) {
hash := *s
for _, c := range data {
hash *= prime64
hash ^= sum64(c)
}
*s = hash
return len(data), nil
}
func (s *sum64a) Write(data []byte) (int, error) {
hash := *s
for _, c := range data {
hash ^= sum64a(c)
hash *= prime64
}
*s = hash
return len(data), nil
}
func (s *sum32) Size() int { return 4 }
func (s *sum32a) Size() int { return 4 }
func (s *sum64) Size() int { return 8 }
func (s *sum64a) Size() int { return 8 }
func (s *sum32) BlockSize() int { return 1 }
func (s *sum32a) BlockSize() int { return 1 }
func (s *sum64) BlockSize() int { return 1 }
func (s *sum64a) BlockSize() int { return 1 }
func (s *sum32) Sum(in []byte) []byte {
v := uint32(*s)
return append(in, byte(v>>24), byte(v>>16), byte(v>>8), byte(v))
}
func (s *sum32a) Sum(in []byte) []byte {
v := uint32(*s)
return append(in, byte(v>>24), byte(v>>16), byte(v>>8), byte(v))
}
func (s *sum64) Sum(in []byte) []byte {
v := uint64(*s)
return append(in, byte(v>>56), byte(v>>48), byte(v>>40), byte(v>>32), byte(v>>24), byte(v>>16), byte(v>>8), byte(v))
}
func (s *sum64a) Sum(in []byte) []byte {
v := uint64(*s)
return append(in, byte(v>>56), byte(v>>48), byte(v>>40), byte(v>>32), byte(v>>24), byte(v>>16), byte(v>>8), byte(v))
}
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