| 1 | // Declarations for hash functions. -*- C++ -*-
|
|---|
| 2 |
|
|---|
| 3 | // Copyright (C) 2010-2021 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
|
|---|
