BitShares-Core  4.0.0
BitShares blockchain implementation and command-line interface software
city.hpp
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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, 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 #pragma once
43 
44 #include <fc/uint128.hpp>
45 
46 #include <stdlib.h> // for size_t.
47 #include <stdint.h>
48 #include <utility>
49 
50 namespace fc {
51 
52 // Hash function for a byte array.
53 uint64_t city_hash64(const char *buf, size_t len);
54 
55 #if SIZE_MAX > UINT32_MAX
56 inline size_t city_hash_size_t(const char *buf, size_t len) { return city_hash64(buf, len); }
57 #else
58 uint32_t city_hash32(const char *buf, size_t len);
59 inline size_t city_hash_size_t(const char *buf, size_t len) { return city_hash32(buf, len); }
60 #endif
61 
62 // Hash function for a byte array.
63 uint128_t city_hash_crc_128(const char *s, size_t len);
64 
65 } // namespace fc
uint32_t city_hash32(const char *buf, size_t len)
Definition: city.cpp:198
uint128_t city_hash_crc_128(const char *s, size_t len)
Definition: city.cpp:649
size_t city_hash_size_t(const char *buf, size_t len)
Definition: city.hpp:59
Definition: api.hpp:15
uint64_t city_hash64(const char *buf, size_t len)
Definition: city.cpp:375