1 | // Declarations for hash functions. -*- C++ -*- |
2 | |
3 | // Copyright (C) 2010-2017 Free Software Foundation, Inc. |
4 | // |
5 | // This file is part of the GNU ISO C++ Library. This library is free |
6 | // software; you can redistribute it and/or modify it under the |
7 | // terms of the GNU General Public License as published by the |
8 | // Free Software Foundation; either version 3, or (at your option) |
9 | // any later version. |
10 | |
11 | // This library is distributed in the hope that it will be useful, |
12 | // but WITHOUT ANY WARRANTY; without even the implied warranty of |
13 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
14 | // GNU General Public License for more details. |
15 | |
16 | // Under Section 7 of GPL version 3, you are granted additional |
17 | // permissions described in the GCC Runtime Library Exception, version |
18 | // 3.1, as published by the Free Software Foundation. |
19 | |
20 | // You should have received a copy of the GNU General Public License and |
21 | // a copy of the GCC Runtime Library Exception along with this program; |
22 | // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see |
23 | // <http://www.gnu.org/licenses/>. |
24 | |
25 | /** @file bits/hash_bytes.h |
26 | * This is an internal header file, included by other library headers. |
27 | * Do not attempt to use it directly. @headername{functional} |
28 | */ |
29 | |
30 | #ifndef _HASH_BYTES_H |
31 | #define _HASH_BYTES_H 1 |
32 | |
33 | #pragma GCC system_header |
34 | |
35 | #include <bits/c++config.h> |
36 | |
37 | namespace std |
38 | { |
39 | _GLIBCXX_BEGIN_NAMESPACE_VERSION |
40 | |
41 | // Hash function implementation for the nontrivial specialization. |
42 | // All of them are based on a primitive that hashes a pointer to a |
43 | // byte array. The actual hash algorithm is not guaranteed to stay |
44 | // the same from release to release -- it may be updated or tuned to |
45 | // improve hash quality or speed. |
46 | size_t |
47 | _Hash_bytes(const void* __ptr, size_t __len, size_t __seed); |
48 | |
49 | // A similar hash primitive, using the FNV hash algorithm. This |
50 | // algorithm is guaranteed to stay the same from release to release. |
51 | // (although it might not produce the same values on different |
52 | // machines.) |
53 | size_t |
54 | _Fnv_hash_bytes(const void* __ptr, size_t __len, size_t __seed); |
55 | |
56 | _GLIBCXX_END_NAMESPACE_VERSION |
57 | } // namespace |
58 | |
59 | #endif |
60 | |