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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
// https://en.wikipedia.org/wiki/Fowler-Noll-Vo_hash_function.
package fnv
import (
"hash"
)
type (
sum32 uint32
sum32a uint32
sum64 uint64
sum64a uint64
sum128 [2]uint64
sum128a [2]uint64
)
const (
offset32 = 2166136261
offset64 = 14695981039346656037
offset128Lower = 0x62b821756295c58d
offset128Higher = 0x6c62272e07bb0142
prime32 = 16777619
prime64 = 1099511628211
prime128Lower = 0x13b
prime128Shift = 24
)
// New32 returns a new 32-bit FNV-1 hash.Hash.
// Its Sum method will lay the value out in big-endian byte order.
func New32() hash.Hash32 {
var s sum32 = offset32
return &s
}
// New32a returns a new 32-bit FNV-1a hash.Hash.
// Its Sum method will lay the value out in big-endian byte order.
func New32a() hash.Hash32 {
var s sum32a = offset32
return &s
}
// New64 returns a new 64-bit FNV-1 hash.Hash.
// Its Sum method will lay the value out in big-endian byte order.
func New64() hash.Hash64 {
var s sum64 = offset64
return &s
}
// New64a returns a new 64-bit FNV-1a hash.Hash.
// Its Sum method will lay the value out in big-endian byte order.
func New64a() hash.Hash64 {
var s sum64a = offset64
return &s
}
// New128 returns a new 128-bit FNV-1 hash.Hash.
// Its Sum method will lay the value out in big-endian byte order.
func New128() hash.Hash {
var s sum128
s[0] = offset128Higher
s[1] = offset128Lower
return &s
}
// New128a returns a new 128-bit FNV-1a hash.Hash.
// Its Sum method will lay the value out in big-endian byte order.
func New128a() hash.Hash {
var s sum128a
s[0] = offset128Higher
s[1] = offset128Lower
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 *sum128) Reset() { s[0] = offset128Higher; s[1] = offset128Lower }
func (s *sum128a) Reset() { s[0] = offset128Higher; s[1] = offset128Lower }
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 *sum128) Write(data []byte) (int, error) {
for _, c := range data {
// Compute the multiplication in 4 parts to simplify carrying
s1l := (s[1] & 0xffffffff) * prime128Lower
s1h := (s[1] >> 32) * prime128Lower
s0l := (s[0]&0xffffffff)*prime128Lower + (s[1]&0xffffffff)<<prime128Shift
s0h := (s[0]>>32)*prime128Lower + (s[1]>>32)<<prime128Shift
// Carries
s1h += s1l >> 32
s0l += s1h >> 32
s0h += s0l >> 32
// Update the values
s[1] = (s1l & 0xffffffff) + (s1h << 32)
s[0] = (s0l & 0xffffffff) + (s0h << 32)
s[1] ^= uint64(c)
}
return len(data), nil
}
func (s *sum128a) Write(data []byte) (int, error) {
for _, c := range data {
s[1] ^= uint64(c)
// Compute the multiplication in 4 parts to simplify carrying
s1l := (s[1] & 0xffffffff) * prime128Lower
s1h := (s[1] >> 32) * prime128Lower
s0l := (s[0]&0xffffffff)*prime128Lower + (s[1]&0xffffffff)<<prime128Shift
s0h := (s[0]>>32)*prime128Lower + (s[1]>>32)<<prime128Shift
// Carries
s1h += s1l >> 32
s0l += s1h >> 32
s0h += s0l >> 32
// Update the values
s[1] = (s1l & 0xffffffff) + (s1h << 32)
s[0] = (s0l & 0xffffffff) + (s0h << 32)
}
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 *sum128) Size() int { return 16 }
func (s *sum128a) Size() int { return 16 }
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 *sum128) BlockSize() int { return 1 }
func (s *sum128a) 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))
}
func (s *sum128) Sum(in []byte) []byte {
return append(in,
byte(s[0]>>56), byte(s[0]>>48), byte(s[0]>>40), byte(s[0]>>32), byte(s[0]>>24), byte(s[0]>>16), byte(s[0]>>8), byte(s[0]),
byte(s[1]>>56), byte(s[1]>>48), byte(s[1]>>40), byte(s[1]>>32), byte(s[1]>>24), byte(s[1]>>16), byte(s[1]>>8), byte(s[1]),
)
}
func (s *sum128a) Sum(in []byte) []byte {
return append(in,
byte(s[0]>>56), byte(s[0]>>48), byte(s[0]>>40), byte(s[0]>>32), byte(s[0]>>24), byte(s[0]>>16), byte(s[0]>>8), byte(s[0]),
byte(s[1]>>56), byte(s[1]>>48), byte(s[1]>>40), byte(s[1]>>32), byte(s[1]>>24), byte(s[1]>>16), byte(s[1]>>8), byte(s[1]),
)
}
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