hash_fun.h

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00001 // 'struct hash' from SGI -*- C++ -*-
00002 
00003 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2009, 2010
00004 // Free Software Foundation, Inc.
00005 //
00006 // This file is part of the GNU ISO C++ Library.  This library is free
00007 // software; you can redistribute it and/or modify it under the
00008 // terms of the GNU General Public License as published by the
00009 // Free Software Foundation; either version 3, or (at your option)
00010 // any later version.
00011 
00012 // This library is distributed in the hope that it will be useful,
00013 // but WITHOUT ANY WARRANTY; without even the implied warranty of
00014 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00015 // GNU General Public License for more details.
00016 
00017 // Under Section 7 of GPL version 3, you are granted additional
00018 // permissions described in the GCC Runtime Library Exception, version
00019 // 3.1, as published by the Free Software Foundation.
00020 
00021 // You should have received a copy of the GNU General Public License and
00022 // a copy of the GCC Runtime Library Exception along with this program;
00023 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
00024 // <http://www.gnu.org/licenses/>.
00025 
00026 /*
00027  * Copyright (c) 1996-1998
00028  * Silicon Graphics Computer Systems, Inc.
00029  *
00030  * Permission to use, copy, modify, distribute and sell this software
00031  * and its documentation for any purpose is hereby granted without fee,
00032  * provided that the above copyright notice appear in all copies and
00033  * that both that copyright notice and this permission notice appear
00034  * in supporting documentation.  Silicon Graphics makes no
00035  * representations about the suitability of this software for any
00036  * purpose.  It is provided "as is" without express or implied warranty.
00037  *
00038  *
00039  * Copyright (c) 1994
00040  * Hewlett-Packard Company
00041  *
00042  * Permission to use, copy, modify, distribute and sell this software
00043  * and its documentation for any purpose is hereby granted without fee,
00044  * provided that the above copyright notice appear in all copies and
00045  * that both that copyright notice and this permission notice appear
00046  * in supporting documentation.  Hewlett-Packard Company makes no
00047  * representations about the suitability of this software for any
00048  * purpose.  It is provided "as is" without express or implied warranty.
00049  *
00050  */
00051 
00052 /** @file backward/hash_fun.h
00053  *  This file is a GNU extension to the Standard C++ Library (possibly
00054  *  containing extensions from the HP/SGI STL subset).
00055  */
00056 
00057 #ifndef _BACKWARD_HASH_FUN_H
00058 #define _BACKWARD_HASH_FUN_H 1
00059 
00060 #include <cstddef>
00061 
00062 _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
00063 
00064   using std::size_t;
00065 
00066   template<class _Key>
00067     struct hash { };
00068 
00069   inline size_t
00070   __stl_hash_string(const char* __s)
00071   {
00072     unsigned long __h = 0;
00073     for ( ; *__s; ++__s)
00074       __h = 5 * __h + *__s;
00075     return size_t(__h);
00076   }
00077 
00078   template<>
00079     struct hash<char*>
00080     {
00081       size_t
00082       operator()(const char* __s) const
00083       { return __stl_hash_string(__s); }
00084     };
00085 
00086   template<>
00087     struct hash<const char*>
00088     {
00089       size_t
00090       operator()(const char* __s) const
00091       { return __stl_hash_string(__s); }
00092     };
00093 
00094   template<>
00095     struct hash<char>
00096     { 
00097       size_t
00098       operator()(char __x) const
00099       { return __x; }
00100     };
00101 
00102   template<>
00103     struct hash<unsigned char>
00104     { 
00105       size_t
00106       operator()(unsigned char __x) const
00107       { return __x; }
00108     };
00109 
00110   template<>
00111     struct hash<signed char>
00112     {
00113       size_t
00114       operator()(unsigned char __x) const
00115       { return __x; }
00116     };
00117 
00118   template<>
00119     struct hash<short>
00120     {
00121       size_t
00122       operator()(short __x) const
00123       { return __x; }
00124     };
00125 
00126   template<>
00127     struct hash<unsigned short>
00128     {
00129       size_t
00130       operator()(unsigned short __x) const
00131       { return __x; }
00132     };
00133 
00134   template<>
00135     struct hash<int>
00136     { 
00137       size_t 
00138       operator()(int __x) const 
00139       { return __x; }
00140     };
00141 
00142   template<>
00143     struct hash<unsigned int>
00144     { 
00145       size_t
00146       operator()(unsigned int __x) const
00147       { return __x; }
00148     };
00149 
00150   template<>
00151     struct hash<long>
00152     {
00153       size_t
00154       operator()(long __x) const
00155       { return __x; }
00156     };
00157 
00158   template<>
00159     struct hash<unsigned long>
00160     {
00161       size_t
00162       operator()(unsigned long __x) const
00163       { return __x; }
00164     };
00165 
00166 _GLIBCXX_END_NAMESPACE
00167 
00168 #endif

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