Editando: fnv.go
// 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 }
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