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 ) 19 20 type ( 21 sum32 uint32 22 sum32a uint32 23 sum64 uint64 24 sum64a uint64 25 sum128 [2]uint64 26 sum128a [2]uint64 27 ) 28 29 const ( 30 offset32 = 2166136261 31 offset64 = 14695981039346656037 32 offset128Lower = 0x62b821756295c58d 33 offset128Higher = 0x6c62272e07bb0142 34 prime32 = 16777619 35 prime64 = 1099511628211 36 prime128Lower = 0x13b 37 prime128Shift = 24 38 ) 39 40 // New32 returns a new 32-bit FNV-1 hash.Hash. 41 // Its Sum method will lay the value out in big-endian byte order. 42 func New32() hash.Hash32 { 43 var s sum32 = offset32 44 return &s 45 } 46 47 // New32a returns a new 32-bit FNV-1a hash.Hash. 48 // Its Sum method will lay the value out in big-endian byte order. 49 func New32a() hash.Hash32 { 50 var s sum32a = offset32 51 return &s 52 } 53 54 // New64 returns a new 64-bit FNV-1 hash.Hash. 55 // Its Sum method will lay the value out in big-endian byte order. 56 func New64() hash.Hash64 { 57 var s sum64 = offset64 58 return &s 59 } 60 61 // New64a returns a new 64-bit FNV-1a hash.Hash. 62 // Its Sum method will lay the value out in big-endian byte order. 63 func New64a() hash.Hash64 { 64 var s sum64a = offset64 65 return &s 66 } 67 68 // New128 returns a new 128-bit FNV-1 hash.Hash. 69 // Its Sum method will lay the value out in big-endian byte order. 70 func New128() hash.Hash { 71 var s sum128 72 s[0] = offset128Higher 73 s[1] = offset128Lower 74 return &s 75 } 76 77 // New128a returns a new 128-bit FNV-1a hash.Hash. 78 // Its Sum method will lay the value out in big-endian byte order. 79 func New128a() hash.Hash { 80 var s sum128a 81 s[0] = offset128Higher 82 s[1] = offset128Lower 83 return &s 84 } 85 86 func (s *sum32) Reset() { *s = offset32 } 87 func (s *sum32a) Reset() { *s = offset32 } 88 func (s *sum64) Reset() { *s = offset64 } 89 func (s *sum64a) Reset() { *s = offset64 } 90 func (s *sum128) Reset() { s[0] = offset128Higher; s[1] = offset128Lower } 91 func (s *sum128a) Reset() { s[0] = offset128Higher; s[1] = offset128Lower } 92 93 func (s *sum32) Sum32() uint32 { return uint32(*s) } 94 func (s *sum32a) Sum32() uint32 { return uint32(*s) } 95 func (s *sum64) Sum64() uint64 { return uint64(*s) } 96 func (s *sum64a) Sum64() uint64 { return uint64(*s) } 97 98 func (s *sum32) Write(data []byte) (int, error) { 99 hash := *s 100 for _, c := range data { 101 hash *= prime32 102 hash ^= sum32(c) 103 } 104 *s = hash 105 return len(data), nil 106 } 107 108 func (s *sum32a) Write(data []byte) (int, error) { 109 hash := *s 110 for _, c := range data { 111 hash ^= sum32a(c) 112 hash *= prime32 113 } 114 *s = hash 115 return len(data), nil 116 } 117 118 func (s *sum64) Write(data []byte) (int, error) { 119 hash := *s 120 for _, c := range data { 121 hash *= prime64 122 hash ^= sum64(c) 123 } 124 *s = hash 125 return len(data), nil 126 } 127 128 func (s *sum64a) Write(data []byte) (int, error) { 129 hash := *s 130 for _, c := range data { 131 hash ^= sum64a(c) 132 hash *= prime64 133 } 134 *s = hash 135 return len(data), nil 136 } 137 138 func (s *sum128) Write(data []byte) (int, error) { 139 for _, c := range data { 140 // Compute the multiplication in 4 parts to simplify carrying 141 s1l := (s[1] & 0xffffffff) * prime128Lower 142 s1h := (s[1] >> 32) * prime128Lower 143 s0l := (s[0]&0xffffffff)*prime128Lower + (s[1]&0xffffffff)<<prime128Shift 144 s0h := (s[0]>>32)*prime128Lower + (s[1]>>32)<<prime128Shift 145 // Carries 146 s1h += s1l >> 32 147 s0l += s1h >> 32 148 s0h += s0l >> 32 149 // Update the values 150 s[1] = (s1l & 0xffffffff) + (s1h << 32) 151 s[0] = (s0l & 0xffffffff) + (s0h << 32) 152 s[1] ^= uint64(c) 153 } 154 return len(data), nil 155 } 156 157 func (s *sum128a) Write(data []byte) (int, error) { 158 for _, c := range data { 159 s[1] ^= uint64(c) 160 // Compute the multiplication in 4 parts to simplify carrying 161 s1l := (s[1] & 0xffffffff) * prime128Lower 162 s1h := (s[1] >> 32) * prime128Lower 163 s0l := (s[0]&0xffffffff)*prime128Lower + (s[1]&0xffffffff)<<prime128Shift 164 s0h := (s[0]>>32)*prime128Lower + (s[1]>>32)<<prime128Shift 165 // Carries 166 s1h += s1l >> 32 167 s0l += s1h >> 32 168 s0h += s0l >> 32 169 // Update the values 170 s[1] = (s1l & 0xffffffff) + (s1h << 32) 171 s[0] = (s0l & 0xffffffff) + (s0h << 32) 172 } 173 return len(data), nil 174 } 175 176 func (s *sum32) Size() int { return 4 } 177 func (s *sum32a) Size() int { return 4 } 178 func (s *sum64) Size() int { return 8 } 179 func (s *sum64a) Size() int { return 8 } 180 func (s *sum128) Size() int { return 16 } 181 func (s *sum128a) Size() int { return 16 } 182 183 func (s *sum32) BlockSize() int { return 1 } 184 func (s *sum32a) BlockSize() int { return 1 } 185 func (s *sum64) BlockSize() int { return 1 } 186 func (s *sum64a) BlockSize() int { return 1 } 187 func (s *sum128) BlockSize() int { return 1 } 188 func (s *sum128a) BlockSize() int { return 1 } 189 190 func (s *sum32) Sum(in []byte) []byte { 191 v := uint32(*s) 192 return append(in, byte(v>>24), byte(v>>16), byte(v>>8), byte(v)) 193 } 194 195 func (s *sum32a) Sum(in []byte) []byte { 196 v := uint32(*s) 197 return append(in, byte(v>>24), byte(v>>16), byte(v>>8), byte(v)) 198 } 199 200 func (s *sum64) Sum(in []byte) []byte { 201 v := uint64(*s) 202 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)) 203 } 204 205 func (s *sum64a) Sum(in []byte) []byte { 206 v := uint64(*s) 207 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)) 208 } 209 210 func (s *sum128) Sum(in []byte) []byte { 211 return append(in, 212 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]), 213 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]), 214 ) 215 } 216 217 func (s *sum128a) Sum(in []byte) []byte { 218 return append(in, 219 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]), 220 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]), 221 ) 222 } 223 224 const ( 225 magic32 = "fnv\x01" 226 magic32a = "fnv\x02" 227 magic64 = "fnv\x03" 228 magic64a = "fnv\x04" 229 magic128 = "fnv\x05" 230 magic128a = "fnv\x06" 231 marshaledSize32 = len(magic32) + 4 232 marshaledSize64 = len(magic64) + 8 233 marshaledSize128 = len(magic128) + 8*2 234 ) 235 236 func (s *sum32) MarshalBinary() ([]byte, error) { 237 b := make([]byte, 0, marshaledSize32) 238 b = append(b, magic32...) 239 b = appendUint32(b, uint32(*s)) 240 return b, nil 241 } 242 243 func (s *sum32a) MarshalBinary() ([]byte, error) { 244 b := make([]byte, 0, marshaledSize32) 245 b = append(b, magic32a...) 246 b = appendUint32(b, uint32(*s)) 247 return b, nil 248 } 249 250 func (s *sum64) MarshalBinary() ([]byte, error) { 251 b := make([]byte, 0, marshaledSize64) 252 b = append(b, magic64...) 253 b = appendUint64(b, uint64(*s)) 254 return b, nil 255 256 } 257 258 func (s *sum64a) MarshalBinary() ([]byte, error) { 259 b := make([]byte, 0, marshaledSize64) 260 b = append(b, magic64a...) 261 b = appendUint64(b, uint64(*s)) 262 return b, nil 263 } 264 265 func (s *sum128) MarshalBinary() ([]byte, error) { 266 b := make([]byte, 0, marshaledSize128) 267 b = append(b, magic128...) 268 b = appendUint64(b, s[0]) 269 b = appendUint64(b, s[1]) 270 return b, nil 271 } 272 273 func (s *sum128a) MarshalBinary() ([]byte, error) { 274 b := make([]byte, 0, marshaledSize128) 275 b = append(b, magic128a...) 276 b = appendUint64(b, s[0]) 277 b = appendUint64(b, s[1]) 278 return b, nil 279 } 280 281 func (s *sum32) UnmarshalBinary(b []byte) error { 282 if len(b) < len(magic32) || string(b[:len(magic32)]) != magic32 { 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 = sum32(readUint32(b[4:])) 289 return nil 290 } 291 292 func (s *sum32a) UnmarshalBinary(b []byte) error { 293 if len(b) < len(magic32a) || string(b[:len(magic32a)]) != magic32a { 294 return errors.New("hash/fnv: invalid hash state identifier") 295 } 296 if len(b) != marshaledSize32 { 297 return errors.New("hash/fnv: invalid hash state size") 298 } 299 *s = sum32a(readUint32(b[4:])) 300 return nil 301 } 302 303 func (s *sum64) UnmarshalBinary(b []byte) error { 304 if len(b) < len(magic64) || string(b[:len(magic64)]) != magic64 { 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 = sum64(readUint64(b[4:])) 311 return nil 312 } 313 314 func (s *sum64a) UnmarshalBinary(b []byte) error { 315 if len(b) < len(magic64a) || string(b[:len(magic64a)]) != magic64a { 316 return errors.New("hash/fnv: invalid hash state identifier") 317 } 318 if len(b) != marshaledSize64 { 319 return errors.New("hash/fnv: invalid hash state size") 320 } 321 *s = sum64a(readUint64(b[4:])) 322 return nil 323 } 324 325 func (s *sum128) UnmarshalBinary(b []byte) error { 326 if len(b) < len(magic128) || string(b[:len(magic128)]) != magic128 { 327 return errors.New("hash/fnv: invalid hash state identifier") 328 } 329 if len(b) != marshaledSize128 { 330 return errors.New("hash/fnv: invalid hash state size") 331 } 332 s[0] = readUint64(b[4:]) 333 s[1] = readUint64(b[12:]) 334 return nil 335 } 336 337 func (s *sum128a) UnmarshalBinary(b []byte) error { 338 if len(b) < len(magic128a) || string(b[:len(magic128a)]) != magic128a { 339 return errors.New("hash/fnv: invalid hash state identifier") 340 } 341 if len(b) != marshaledSize128 { 342 return errors.New("hash/fnv: invalid hash state size") 343 } 344 s[0] = readUint64(b[4:]) 345 s[1] = readUint64(b[12:]) 346 return nil 347 } 348 349 func readUint32(b []byte) uint32 { 350 _ = b[3] 351 return uint32(b[3]) | uint32(b[2])<<8 | uint32(b[1])<<16 | uint32(b[0])<<24 352 } 353 354 func appendUint32(b []byte, x uint32) []byte { 355 a := [4]byte{ 356 byte(x >> 24), 357 byte(x >> 16), 358 byte(x >> 8), 359 byte(x), 360 } 361 return append(b, a[:]...) 362 } 363 364 func appendUint64(b []byte, x uint64) []byte { 365 a := [8]byte{ 366 byte(x >> 56), 367 byte(x >> 48), 368 byte(x >> 40), 369 byte(x >> 32), 370 byte(x >> 24), 371 byte(x >> 16), 372 byte(x >> 8), 373 byte(x), 374 } 375 return append(b, a[:]...) 376 } 377 378 func readUint64(b []byte) uint64 { 379 _ = b[7] 380 return uint64(b[7]) | uint64(b[6])<<8 | uint64(b[5])<<16 | uint64(b[4])<<24 | 381 uint64(b[3])<<32 | uint64(b[2])<<40 | uint64(b[1])<<48 | uint64(b[0])<<56 382 } 383
