// 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.
//
// All the hash.Hash implementations returned by this package also
// implement encoding.BinaryMarshaler and encoding.BinaryUnmarshaler to
// marshal and unmarshal the internal state of the hash.
package fnv
import (
"errors"
"hash"
"math/bits"
)
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
s0, s1 := bits.Mul64(prime128Lower, s[1])
s0 += s[1]<<prime128Shift + prime128Lower*s[0]
// Update the values
s[1] = s1
s[0] = s0
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
s0, s1 := bits.Mul64(prime128Lower, s[1])
s0 += s[1]<<prime128Shift + prime128Lower*s[0]
// Update the values
s[1] = s1
s[0] = s0
}
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]),
)
}
const (
magic32 = "fnv\x01"
magic32a = "fnv\x02"
magic64 = "fnv\x03"
magic64a = "fnv\x04"
magic128 = "fnv\x05"
magic128a = "fnv\x06"
marshaledSize32 = len(magic32) + 4
marshaledSize64 = len(magic64) + 8
marshaledSize128 = len(magic128) + 8*2
)
func (s *sum32) MarshalBinary() ([]byte, error) {
b := make([]byte, 0, marshaledSize32)
b = append(b, magic32...)
b = appendUint32(b, uint32(*s))
return b, nil
}
func (s *sum32a) MarshalBinary() ([]byte, error) {
b := make([]byte, 0, marshaledSize32)
b = append(b, magic32a...)
b = appendUint32(b, uint32(*s))
return b, nil
}
func (s *sum64) MarshalBinary() ([]byte, error) {
b := make([]byte, 0, marshaledSize64)
b = append(b, magic64...)
b = appendUint64(b, uint64(*s))
return b, nil
}
func (s *sum64a) MarshalBinary() ([]byte, error) {
b := make([]byte, 0, marshaledSize64)
b = append(b, magic64a...)
b = appendUint64(b, uint64(*s))
return b, nil
}
func (s *sum128) MarshalBinary() ([]byte, error) {
b := make([]byte, 0, marshaledSize128)
b = append(b, magic128...)
b = appendUint64(b, s[0])
b = appendUint64(b, s[1])
return b, nil
}
func (s *sum128a) MarshalBinary() ([]byte, error) {
b := make([]byte, 0, marshaledSize128)
b = append(b, magic128a...)
b = appendUint64(b, s[0])
b = appendUint64(b, s[1])
return b, nil
}
func (s *sum32) UnmarshalBinary(b []byte) error {
if len(b) < len(magic32) || string(b[:len(magic32)]) != magic32 {
return errors.New("hash/fnv: invalid hash state identifier")
}
if len(b) != marshaledSize32 {
return errors.New("hash/fnv: invalid hash state size")
}
*s = sum32(readUint32(b[4:]))
return nil
}
func (s *sum32a) UnmarshalBinary(b []byte) error {
if len(b) < len(magic32a) || string(b[:len(magic32a)]) != magic32a {
return errors.New("hash/fnv: invalid hash state identifier")
}
if len(b) != marshaledSize32 {
return errors.New("hash/fnv: invalid hash state size")
}
*s = sum32a(readUint32(b[4:]))
return nil
}
func (s *sum64) UnmarshalBinary(b []byte) error {
if len(b) < len(magic64) || string(b[:len(magic64)]) != magic64 {
return errors.New("hash/fnv: invalid hash state identifier")
}
if len(b) != marshaledSize64 {
return errors.New("hash/fnv: invalid hash state size")
}
*s = sum64(readUint64(b[4:]))
return nil
}
func (s *sum64a) UnmarshalBinary(b []byte) error {
if len(b) < len(magic64a) || string(b[:len(magic64a)]) != magic64a {
return errors.New("hash/fnv: invalid hash state identifier")
}
if len(b) != marshaledSize64 {
return errors.New("hash/fnv: invalid hash state size")
}
*s = sum64a(readUint64(b[4:]))
return nil
}
func (s *sum128) UnmarshalBinary(b []byte) error {
if len(b) < len(magic128) || string(b[:len(magic128)]) != magic128 {
return errors.New("hash/fnv: invalid hash state identifier")
}
if len(b) != marshaledSize128 {
return errors.New("hash/fnv: invalid hash state size")
}
s[0] = readUint64(b[4:])
s[1] = readUint64(b[12:])
return nil
}
func (s *sum128a) UnmarshalBinary(b []byte) error {
if len(b) < len(magic128a) || string(b[:len(magic128a)]) != magic128a {
return errors.New("hash/fnv: invalid hash state identifier")
}
if len(b) != marshaledSize128 {
return errors.New("hash/fnv: invalid hash state size")
}
s[0] = readUint64(b[4:])
s[1] = readUint64(b[12:])
return nil
}
func readUint32(b []byte) uint32 {
_ = b[3]
return uint32(b[3]) | uint32(b[2])<<8 | uint32(b[1])<<16 | uint32(b[0])<<24
}
func appendUint32(b []byte, x uint32) []byte {
a := [4]byte{
byte(x >> 24),
byte(x >> 16),
byte(x >> 8),
byte(x),
}
return append(b, a[:]...)
}
func appendUint64(b []byte, x uint64) []byte {
a := [8]byte{
byte(x >> 56),
byte(x >> 48),
byte(x >> 40),
byte(x >> 32),
byte(x >> 24),
byte(x >> 16),
byte(x >> 8),
byte(x),
}
return append(b, a[:]...)
}
func readUint64(b []byte) uint64 {
_ = b[7]
return uint64(b[7]) | uint64(b[6])<<8 | uint64(b[5])<<16 | uint64(b[4])<<24 |
uint64(b[3])<<32 | uint64(b[2])<<40 | uint64(b[1])<<48 | uint64(b[0])<<56
}
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