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Diffstat (limited to '')
| -rw-r--r-- | src/hash/fnv/fnv.go | 371 |
1 files changed, 371 insertions, 0 deletions
diff --git a/src/hash/fnv/fnv.go b/src/hash/fnv/fnv.go new file mode 100644 index 0000000..0fce177 --- /dev/null +++ b/src/hash/fnv/fnv.go @@ -0,0 +1,371 @@ +// 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 +} |