libstdc++
hash_bytes.h
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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