| // Declarations for hash functions. -*- C++ -*- |
| |
| // Copyright (C) 2010-2021 Free Software Foundation, Inc. |
| // |
| // This file is part of the GNU ISO C++ Library. This library is free |
| // software; you can redistribute it and/or modify it under the |
| // terms of the GNU General Public License as published by the |
| // Free Software Foundation; either version 3, or (at your option) |
| // any later version. |
| |
| // This library is distributed in the hope that it will be useful, |
| // but WITHOUT ANY WARRANTY; without even the implied warranty of |
| // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| // GNU General Public License for more details. |
| |
| // Under Section 7 of GPL version 3, you are granted additional |
| // permissions described in the GCC Runtime Library Exception, version |
| // 3.1, as published by the Free Software Foundation. |
| |
| // You should have received a copy of the GNU General Public License and |
| // a copy of the GCC Runtime Library Exception along with this program; |
| // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see |
| // <http://www.gnu.org/licenses/>. |
| |
| /** @file bits/hash_bytes.h |
| * This is an internal header file, included by other library headers. |
| * Do not attempt to use it directly. @headername{functional} |
| */ |
| |
| #ifndef _HASH_BYTES_H |
| #define _HASH_BYTES_H 1 |
| |
| #pragma GCC system_header |
| |
| #include <bits/c++config.h> |
| |
| namespace std |
| { |
| _GLIBCXX_BEGIN_NAMESPACE_VERSION |
| |
| // Hash function implementation for the nontrivial specialization. |
| // All of them are based on a primitive that hashes a pointer to a |
| // byte array. The actual hash algorithm is not guaranteed to stay |
| // the same from release to release -- it may be updated or tuned to |
| // improve hash quality or speed. |
| size_t |
| _Hash_bytes(const void* __ptr, size_t __len, size_t __seed); |
| |
| // A similar hash primitive, using the FNV hash algorithm. This |
| // algorithm is guaranteed to stay the same from release to release. |
| // (although it might not produce the same values on different |
| // machines.) |
| size_t |
| _Fnv_hash_bytes(const void* __ptr, size_t __len, size_t __seed); |
| |
| _GLIBCXX_END_NAMESPACE_VERSION |
| } // namespace |
| |
| #endif |