libstdc++
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00001 // Declarations for hash functions. -*- C++ -*- 00002 00003 // Copyright (C) 2010, 2011 Free Software Foundation, Inc. 00004 // 00005 // This file is part of the GNU ISO C++ Library. This library is free 00006 // software; you can redistribute it and/or modify it under the 00007 // terms of the GNU General Public License as published by the 00008 // Free Software Foundation; either version 3, or (at your option) 00009 // any later version. 00010 00011 // This library is distributed in the hope that it will be useful, 00012 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00014 // GNU General Public License for more details. 00015 00016 // Under Section 7 of GPL version 3, you are granted additional 00017 // permissions described in the GCC Runtime Library Exception, version 00018 // 3.1, as published by the Free Software Foundation. 00019 00020 // You should have received a copy of the GNU General Public License and 00021 // a copy of the GCC Runtime Library Exception along with this program; 00022 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 00023 // <http://www.gnu.org/licenses/>. 00024 00025 /** @file bits/hash_bytes.h 00026 * This is an internal header file, included by other library headers. 00027 * Do not attempt to use it directly. @headername{functional} 00028 */ 00029 00030 #ifndef _HASH_BYTES_H 00031 #define _HASH_BYTES_H 1 00032 00033 #pragma GCC system_header 00034 00035 #include <bits/c++config.h> 00036 00037 namespace std 00038 { 00039 _GLIBCXX_BEGIN_NAMESPACE_VERSION 00040 00041 // Hash function implementation for the nontrivial specialization. 00042 // All of them are based on a primitive that hashes a pointer to a 00043 // byte array. The actual hash algorithm is not guaranteed to stay 00044 // the same from release to release -- it may be updated or tuned to 00045 // improve hash quality or speed. 00046 size_t 00047 _Hash_bytes(const void* __ptr, size_t __len, size_t __seed); 00048 00049 // A similar hash primitive, using the FNV hash algorithm. This 00050 // algorithm is guaranteed to stay the same from release to release. 00051 // (although it might not produce the same values on different 00052 // machines.) 00053 size_t 00054 _Fnv_hash_bytes(const void* __ptr, size_t __len, size_t __seed); 00055 00056 _GLIBCXX_END_NAMESPACE_VERSION 00057 } // namespace 00058 00059 #endif