| // 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 |
| } |
| |
| // readUint32 is semantically the same as [binary.BigEndian.Uint32] |
| // We copied this function because we can not import "encoding/binary" here. |
| func readUint32(b []byte) uint32 { |
| _ = b[3] |
| return uint32(b[3]) | uint32(b[2])<<8 | uint32(b[1])<<16 | uint32(b[0])<<24 |
| } |
| |
| // appendUint32 is semantically the same as [binary.BigEndian.AppendUint32] |
| // We copied this function because we can not import "encoding/binary" here. |
| func appendUint32(b []byte, x uint32) []byte { |
| return append(b, |
| byte(x>>24), |
| byte(x>>16), |
| byte(x>>8), |
| byte(x), |
| ) |
| } |
| |
| // appendUint64 is semantically the same as [binary.BigEndian.AppendUint64] |
| // We copied this function because we can not import "encoding/binary" here. |
| func appendUint64(b []byte, x uint64) []byte { |
| return append(b, |
| byte(x>>56), |
| byte(x>>48), |
| byte(x>>40), |
| byte(x>>32), |
| byte(x>>24), |
| byte(x>>16), |
| byte(x>>8), |
| byte(x), |
| ) |
| } |
| |
| // readUint64 is semantically the same as [binary.BigEndian.Uint64] |
| // We copied this function because we can not import "encoding/binary" here. |
| 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 |
| } |
