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comparison: other-licenses/nsis/Contrib/CityHash/cityhash/city.h
other-licenses/nsis/Contrib/CityHash/cityhash/city.h
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| 1 // Copyright (c) 2011 Google, Inc. | |
| 2 // | |
| 3 // Permission is hereby granted, free of charge, to any person obtaining a copy | |
| 4 // of this software and associated documentation files (the "Software"), to deal | |
| 5 // in the Software without restriction, including without limitation the rights | |
| 6 // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
| 7 // copies of the Software, and to permit persons to whom the Software is | |
| 8 // furnished to do so, subject to the following conditions: | |
| 9 // | |
| 10 // The above copyright notice and this permission notice shall be included in | |
| 11 // all copies or substantial portions of the Software. | |
| 12 // | |
| 13 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
| 14 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
| 15 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
| 16 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
| 17 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
| 18 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN | |
| 19 // THE SOFTWARE. | |
| 20 // | |
| 21 // CityHash Version 1, by Geoff Pike and Jyrki Alakuijala | |
| 22 // | |
| 23 // This file provides a few functions for hashing strings. On x86-64 | |
| 24 // hardware in 2011, CityHash64() is faster than other high-quality | |
| 25 // hash functions, such as Murmur. This is largely due to higher | |
| 26 // instruction-level parallelism. CityHash64() and CityHash128() also perform | |
| 27 // well on hash-quality tests. | |
| 28 // | |
| 29 // CityHash128() is optimized for relatively long strings and returns | |
| 30 // a 128-bit hash. For strings more than about 2000 bytes it can be | |
| 31 // faster than CityHash64(). | |
| 32 // | |
| 33 // Functions in the CityHash family are not suitable for cryptography. | |
| 34 // | |
| 35 // WARNING: This code has not been tested on big-endian platforms! | |
| 36 // It is known to work well on little-endian platforms that have a small penalty | |
| 37 // for unaligned reads, such as current Intel and AMD moderate-to-high-end CPUs. | |
| 38 // | |
| 39 // By the way, for some hash functions, given strings a and b, the hash | |
| 40 // of a+b is easily derived from the hashes of a and b. This property | |
| 41 // doesn't hold for any hash functions in this file. | |
| 42 | |
| 43 #ifndef CITY_HASH_H_ | |
| 44 #define CITY_HASH_H_ | |
| 45 | |
| 46 #include "../CityHash.h" // added by moz, specific to nsis project | |
| 47 | |
| 48 #include <stdlib.h> // for size_t. | |
| 49 #include <utility> | |
| 50 | |
| 51 typedef unsigned __int8 uint8; | |
| 52 typedef unsigned __int32 uint32; | |
| 53 typedef unsigned __int64 uint64; | |
| 54 typedef std::pair<uint64, uint64> uint128; | |
| 55 | |
| 56 inline uint64 Uint128Low64(const uint128& x) { return x.first; } | |
| 57 inline uint64 Uint128High64(const uint128& x) { return x.second; } | |
| 58 | |
| 59 // Hash function for a byte array. | |
| 60 uint64 CityHash64(const char *buf, size_t len); | |
| 61 | |
| 62 // Hash function for a byte array. For convenience, a 64-bit seed is also | |
| 63 // hashed into the result. | |
| 64 uint64 CityHash64WithSeed(const char *buf, size_t len, uint64 seed); | |
| 65 | |
| 66 // Hash function for a byte array. For convenience, two seeds are also | |
| 67 // hashed into the result. | |
| 68 uint64 CityHash64WithSeeds(const char *buf, size_t len, | |
| 69 uint64 seed0, uint64 seed1); | |
| 70 | |
| 71 // Hash function for a byte array. | |
| 72 uint128 CityHash128(const char *s, size_t len); | |
| 73 | |
| 74 // Hash function for a byte array. For convenience, a 128-bit seed is also | |
| 75 // hashed into the result. | |
| 76 uint128 CityHash128WithSeed(const char *s, size_t len, uint128 seed); | |
| 77 | |
| 78 // Hash 128 input bits down to 64 bits of output. | |
| 79 // This is intended to be a reasonably good hash function. | |
| 80 inline uint64 Hash128to64(const uint128& x) { | |
| 81 // Murmur-inspired hashing. | |
| 82 const uint64 kMul = 0x9ddfea08eb382d69; | |
| 83 uint64 a = (Uint128Low64(x) ^ Uint128High64(x)) * kMul; | |
| 84 a ^= (a >> 47); | |
| 85 uint64 b = (Uint128High64(x) ^ a) * kMul; | |
| 86 b ^= (b >> 47); | |
| 87 b *= kMul; | |
| 88 return b; | |
| 89 } | |
| 90 | |
| 91 #endif // CITY_HASH_H_ |
