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-rw-r--r--src/hash/fnv/fnv.go376
1 files changed, 376 insertions, 0 deletions
diff --git a/src/hash/fnv/fnv.go b/src/hash/fnv/fnv.go
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+++ b/src/hash/fnv/fnv.go
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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.
+//
+// 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
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-30 04:50:51 +0000