contrib/gcc-4.4/libstdc++-v3/include/backward/hash_fun.h

   1 // 'struct hash' from SGI -*- C++ -*-
   2
   3 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2009 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 /*
  26  * Copyright (c) 1996-1998
  27  * Silicon Graphics Computer Systems, Inc.
  28  *
  29  * Permission to use, copy, modify, distribute and sell this software
  30  * and its documentation for any purpose is hereby granted without fee,
  31  * provided that the above copyright notice appear in all copies and
  32  * that both that copyright notice and this permission notice appear
  33  * in supporting documentation.  Silicon Graphics makes no
  34  * representations about the suitability of this software for any
  35  * purpose.  It is provided "as is" without express or implied warranty.
  36  *
  37  *
  38  * Copyright (c) 1994
  39  * Hewlett-Packard Company
  40  *
  41  * Permission to use, copy, modify, distribute and sell this software
  42  * and its documentation for any purpose is hereby granted without fee,
  43  * provided that the above copyright notice appear in all copies and
  44  * that both that copyright notice and this permission notice appear
  45  * in supporting documentation.  Hewlett-Packard Company makes no
  46  * representations about the suitability of this software for any
  47  * purpose.  It is provided "as is" without express or implied warranty.
  48  *
  49  */
  50
  51 /** @file backward/hash_fun.h
  52  *  This file is a GNU extension to the Standard C++ Library (possibly
  53  *  containing extensions from the HP/SGI STL subset).
  54  */
  55
  56 #ifndef _HASH_FUN_H
  57 #define _HASH_FUN_H 1
  58
  59 #include <cstddef>
  60
  61 _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
  62
  63   using std::size_t;
  64
  65   template<class _Key>
  66     struct hash { };
  67
  68   inline size_t
  69   __stl_hash_string(const char* __s)
  70   {
  71     unsigned long __h = 0;
  72     for ( ; *__s; ++__s)
  73       __h = 5 * __h + *__s;
  74     return size_t(__h);
  75   }
  76
  77   template<>
  78     struct hash<char*>
  79     {
  80       size_t
  81       operator()(const char* __s) const
  82       { return __stl_hash_string(__s); }
  83     };
  84
  85   template<>
  86     struct hash<const char*>
  87     {
  88       size_t
  89       operator()(const char* __s) const
  90       { return __stl_hash_string(__s); }
  91     };
  92
  93   template<>
  94     struct hash<char>
  95     {
  96       size_t
  97       operator()(char __x) const
  98       { return __x; }
  99     };
 100
 101   template<>
 102     struct hash<unsigned char>
 103     {
 104       size_t
 105       operator()(unsigned char __x) const
 106       { return __x; }
 107     };
 108
 109   template<>
 110     struct hash<signed char>
 111     {
 112       size_t
 113       operator()(unsigned char __x) const
 114       { return __x; }
 115     };
 116
 117   template<>
 118     struct hash<short>
 119     {
 120       size_t
 121       operator()(short __x) const
 122       { return __x; }
 123     };
 124
 125   template<>
 126     struct hash<unsigned short>
 127     {
 128       size_t
 129       operator()(unsigned short __x) const
 130       { return __x; }
 131     };
 132
 133   template<>
 134     struct hash<int>
 135     {
 136       size_t
 137       operator()(int __x) const
 138       { return __x; }
 139     };
 140
 141   template<>
 142     struct hash<unsigned int>
 143     {
 144       size_t
 145       operator()(unsigned int __x) const
 146       { return __x; }
 147     };
 148
 149   template<>
 150     struct hash<long>
 151     {
 152       size_t
 153       operator()(long __x) const
 154       { return __x; }
 155     };
 156
 157   template<>
 158     struct hash<unsigned long>
 159     {
 160       size_t
 161       operator()(unsigned long __x) const
 162       { return __x; }
 163     };
 164
 165 _GLIBCXX_END_NAMESPACE
 166
 167 #endif