github.com/geraldss/go/src@v0.0.0-20210511222824-ac7d0ebfc235/hash/fnv/fnv.go (about) 1 // Copyright 2011 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 // Package fnv implements FNV-1 and FNV-1a, non-cryptographic hash functions 6 // created by Glenn Fowler, Landon Curt Noll, and Phong Vo. 7 // See 8 // https://en.wikipedia.org/wiki/Fowler-Noll-Vo_hash_function. 9 // 10 // All the hash.Hash implementations returned by this package also 11 // implement encoding.BinaryMarshaler and encoding.BinaryUnmarshaler to 12 // marshal and unmarshal the internal state of the hash. 13 package fnv 14 15 import ( 16 "errors" 17 "hash" 18 "math/bits" 19 ) 20 21 type ( 22 sum32 uint32 23 sum32a uint32 24 sum64 uint64 25 sum64a uint64 26 sum128 [2]uint64 27 sum128a [2]uint64 28 ) 29 30 const ( 31 offset32 = 2166136261 32 offset64 = 14695981039346656037 33 offset128Lower = 0x62b821756295c58d 34 offset128Higher = 0x6c62272e07bb0142 35 prime32 = 16777619 36 prime64 = 1099511628211 37 prime128Lower = 0x13b 38 prime128Shift = 24 39 ) 40 41 // New32 returns a new 32-bit FNV-1 hash.Hash. 42 // Its Sum method will lay the value out in big-endian byte order. 43 func New32() hash.Hash32 { 44 var s sum32 = offset32 45 return &s 46 } 47 48 // New32a returns a new 32-bit FNV-1a hash.Hash. 49 // Its Sum method will lay the value out in big-endian byte order. 50 func New32a() hash.Hash32 { 51 var s sum32a = offset32 52 return &s 53 } 54 55 // New64 returns a new 64-bit FNV-1 hash.Hash. 56 // Its Sum method will lay the value out in big-endian byte order. 57 func New64() hash.Hash64 { 58 var s sum64 = offset64 59 return &s 60 } 61 62 // New64a returns a new 64-bit FNV-1a hash.Hash. 63 // Its Sum method will lay the value out in big-endian byte order. 64 func New64a() hash.Hash64 { 65 var s sum64a = offset64 66 return &s 67 } 68 69 // New128 returns a new 128-bit FNV-1 hash.Hash. 70 // Its Sum method will lay the value out in big-endian byte order. 71 func New128() hash.Hash { 72 var s sum128 73 s[0] = offset128Higher 74 s[1] = offset128Lower 75 return &s 76 } 77 78 // New128a returns a new 128-bit FNV-1a hash.Hash. 79 // Its Sum method will lay the value out in big-endian byte order. 80 func New128a() hash.Hash { 81 var s sum128a 82 s[0] = offset128Higher 83 s[1] = offset128Lower 84 return &s 85 } 86 87 func (s *sum32) Reset() { *s = offset32 } 88 func (s *sum32a) Reset() { *s = offset32 } 89 func (s *sum64) Reset() { *s = offset64 } 90 func (s *sum64a) Reset() { *s = offset64 } 91 func (s *sum128) Reset() { s[0] = offset128Higher; s[1] = offset128Lower } 92 func (s *sum128a) Reset() { s[0] = offset128Higher; s[1] = offset128Lower } 93 94 func (s *sum32) Sum32() uint32 { return uint32(*s) } 95 func (s *sum32a) Sum32() uint32 { return uint32(*s) } 96 func (s *sum64) Sum64() uint64 { return uint64(*s) } 97 func (s *sum64a) Sum64() uint64 { return uint64(*s) } 98 99 func (s *sum32) Write(data []byte) (int, error) { 100 hash := *s 101 for _, c := range data { 102 hash *= prime32 103 hash ^= sum32(c) 104 } 105 *s = hash 106 return len(data), nil 107 } 108 109 func (s *sum32a) Write(data []byte) (int, error) { 110 hash := *s 111 for _, c := range data { 112 hash ^= sum32a(c) 113 hash *= prime32 114 } 115 *s = hash 116 return len(data), nil 117 } 118 119 func (s *sum64) Write(data []byte) (int, error) { 120 hash := *s 121 for _, c := range data { 122 hash *= prime64 123 hash ^= sum64(c) 124 } 125 *s = hash 126 return len(data), nil 127 } 128 129 func (s *sum64a) Write(data []byte) (int, error) { 130 hash := *s 131 for _, c := range data { 132 hash ^= sum64a(c) 133 hash *= prime64 134 } 135 *s = hash 136 return len(data), nil 137 } 138 139 func (s *sum128) Write(data []byte) (int, error) { 140 for _, c := range data { 141 // Compute the multiplication 142 s0, s1 := bits.Mul64(prime128Lower, s[1]) 143 s0 += s[1]<<prime128Shift + prime128Lower*s[0] 144 // Update the values 145 s[1] = s1 146 s[0] = s0 147 s[1] ^= uint64(c) 148 } 149 return len(data), nil 150 } 151 152 func (s *sum128a) Write(data []byte) (int, error) { 153 for _, c := range data { 154 s[1] ^= uint64(c) 155 // Compute the multiplication 156 s0, s1 := bits.Mul64(prime128Lower, s[1]) 157 s0 += s[1]<<prime128Shift + prime128Lower*s[0] 158 // Update the values 159 s[1] = s1 160 s[0] = s0 161 } 162 return len(data), nil 163 } 164 165 func (s *sum32) Size() int { return 4 } 166 func (s *sum32a) Size() int { return 4 } 167 func (s *sum64) Size() int { return 8 } 168 func (s *sum64a) Size() int { return 8 } 169 func (s *sum128) Size() int { return 16 } 170 func (s *sum128a) Size() int { return 16 } 171 172 func (s *sum32) BlockSize() int { return 1 } 173 func (s *sum32a) BlockSize() int { return 1 } 174 func (s *sum64) BlockSize() int { return 1 } 175 func (s *sum64a) BlockSize() int { return 1 } 176 func (s *sum128) BlockSize() int { return 1 } 177 func (s *sum128a) BlockSize() int { return 1 } 178 179 func (s *sum32) Sum(in []byte) []byte { 180 v := uint32(*s) 181 return append(in, byte(v>>24), byte(v>>16), byte(v>>8), byte(v)) 182 } 183 184 func (s *sum32a) Sum(in []byte) []byte { 185 v := uint32(*s) 186 return append(in, byte(v>>24), byte(v>>16), byte(v>>8), byte(v)) 187 } 188 189 func (s *sum64) Sum(in []byte) []byte { 190 v := uint64(*s) 191 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)) 192 } 193 194 func (s *sum64a) Sum(in []byte) []byte { 195 v := uint64(*s) 196 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)) 197 } 198 199 func (s *sum128) Sum(in []byte) []byte { 200 return append(in, 201 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]), 202 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]), 203 ) 204 } 205 206 func (s *sum128a) Sum(in []byte) []byte { 207 return append(in, 208 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]), 209 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]), 210 ) 211 } 212 213 const ( 214 magic32 = "fnv\x01" 215 magic32a = "fnv\x02" 216 magic64 = "fnv\x03" 217 magic64a = "fnv\x04" 218 magic128 = "fnv\x05" 219 magic128a = "fnv\x06" 220 marshaledSize32 = len(magic32) + 4 221 marshaledSize64 = len(magic64) + 8 222 marshaledSize128 = len(magic128) + 8*2 223 ) 224 225 func (s *sum32) MarshalBinary() ([]byte, error) { 226 b := make([]byte, 0, marshaledSize32) 227 b = append(b, magic32...) 228 b = appendUint32(b, uint32(*s)) 229 return b, nil 230 } 231 232 func (s *sum32a) MarshalBinary() ([]byte, error) { 233 b := make([]byte, 0, marshaledSize32) 234 b = append(b, magic32a...) 235 b = appendUint32(b, uint32(*s)) 236 return b, nil 237 } 238 239 func (s *sum64) MarshalBinary() ([]byte, error) { 240 b := make([]byte, 0, marshaledSize64) 241 b = append(b, magic64...) 242 b = appendUint64(b, uint64(*s)) 243 return b, nil 244 245 } 246 247 func (s *sum64a) MarshalBinary() ([]byte, error) { 248 b := make([]byte, 0, marshaledSize64) 249 b = append(b, magic64a...) 250 b = appendUint64(b, uint64(*s)) 251 return b, nil 252 } 253 254 func (s *sum128) MarshalBinary() ([]byte, error) { 255 b := make([]byte, 0, marshaledSize128) 256 b = append(b, magic128...) 257 b = appendUint64(b, s[0]) 258 b = appendUint64(b, s[1]) 259 return b, nil 260 } 261 262 func (s *sum128a) MarshalBinary() ([]byte, error) { 263 b := make([]byte, 0, marshaledSize128) 264 b = append(b, magic128a...) 265 b = appendUint64(b, s[0]) 266 b = appendUint64(b, s[1]) 267 return b, nil 268 } 269 270 func (s *sum32) UnmarshalBinary(b []byte) error { 271 if len(b) < len(magic32) || string(b[:len(magic32)]) != magic32 { 272 return errors.New("hash/fnv: invalid hash state identifier") 273 } 274 if len(b) != marshaledSize32 { 275 return errors.New("hash/fnv: invalid hash state size") 276 } 277 *s = sum32(readUint32(b[4:])) 278 return nil 279 } 280 281 func (s *sum32a) UnmarshalBinary(b []byte) error { 282 if len(b) < len(magic32a) || string(b[:len(magic32a)]) != magic32a { 283 return errors.New("hash/fnv: invalid hash state identifier") 284 } 285 if len(b) != marshaledSize32 { 286 return errors.New("hash/fnv: invalid hash state size") 287 } 288 *s = sum32a(readUint32(b[4:])) 289 return nil 290 } 291 292 func (s *sum64) UnmarshalBinary(b []byte) error { 293 if len(b) < len(magic64) || string(b[:len(magic64)]) != magic64 { 294 return errors.New("hash/fnv: invalid hash state identifier") 295 } 296 if len(b) != marshaledSize64 { 297 return errors.New("hash/fnv: invalid hash state size") 298 } 299 *s = sum64(readUint64(b[4:])) 300 return nil 301 } 302 303 func (s *sum64a) UnmarshalBinary(b []byte) error { 304 if len(b) < len(magic64a) || string(b[:len(magic64a)]) != magic64a { 305 return errors.New("hash/fnv: invalid hash state identifier") 306 } 307 if len(b) != marshaledSize64 { 308 return errors.New("hash/fnv: invalid hash state size") 309 } 310 *s = sum64a(readUint64(b[4:])) 311 return nil 312 } 313 314 func (s *sum128) UnmarshalBinary(b []byte) error { 315 if len(b) < len(magic128) || string(b[:len(magic128)]) != magic128 { 316 return errors.New("hash/fnv: invalid hash state identifier") 317 } 318 if len(b) != marshaledSize128 { 319 return errors.New("hash/fnv: invalid hash state size") 320 } 321 s[0] = readUint64(b[4:]) 322 s[1] = readUint64(b[12:]) 323 return nil 324 } 325 326 func (s *sum128a) UnmarshalBinary(b []byte) error { 327 if len(b) < len(magic128a) || string(b[:len(magic128a)]) != magic128a { 328 return errors.New("hash/fnv: invalid hash state identifier") 329 } 330 if len(b) != marshaledSize128 { 331 return errors.New("hash/fnv: invalid hash state size") 332 } 333 s[0] = readUint64(b[4:]) 334 s[1] = readUint64(b[12:]) 335 return nil 336 } 337 338 func readUint32(b []byte) uint32 { 339 _ = b[3] 340 return uint32(b[3]) | uint32(b[2])<<8 | uint32(b[1])<<16 | uint32(b[0])<<24 341 } 342 343 func appendUint32(b []byte, x uint32) []byte { 344 a := [4]byte{ 345 byte(x >> 24), 346 byte(x >> 16), 347 byte(x >> 8), 348 byte(x), 349 } 350 return append(b, a[:]...) 351 } 352 353 func appendUint64(b []byte, x uint64) []byte { 354 a := [8]byte{ 355 byte(x >> 56), 356 byte(x >> 48), 357 byte(x >> 40), 358 byte(x >> 32), 359 byte(x >> 24), 360 byte(x >> 16), 361 byte(x >> 8), 362 byte(x), 363 } 364 return append(b, a[:]...) 365 } 366 367 func readUint64(b []byte) uint64 { 368 _ = b[7] 369 return uint64(b[7]) | uint64(b[6])<<8 | uint64(b[5])<<16 | uint64(b[4])<<24 | 370 uint64(b[3])<<32 | uint64(b[2])<<40 | uint64(b[1])<<48 | uint64(b[0])<<56 371 }