1 // Declarations for hash functions. -*- C++ -*- 2 3 // Copyright (C) 2010-2013 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
