libstdc++-v3/include/ext/stl_hash_fun.h

   1 // 'struct hash' from SGI -*- C++ -*-
   2
   3 // Copyright (C) 2001, 2002 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 2, 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 // You should have received a copy of the GNU General Public License along
  17 // with this library; see the file COPYING.  If not, write to the Free
  18 // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
  19 // USA.
  20
  21 // As a special exception, you may use this file as part of a free software
  22 // library without restriction.  Specifically, if other files instantiate
  23 // templates or use macros or inline functions from this file, or you compile
  24 // this file and link it with other files to produce an executable, this
  25 // file does not by itself cause the resulting executable to be covered by
  26 // the GNU General Public License.  This exception does not however
  27 // invalidate any other reasons why the executable file might be covered by
  28 // the GNU General Public License.
  29
  30 /*
  31  * Copyright (c) 1996-1998
  32  * Silicon Graphics Computer Systems, Inc.
  33  *
  34  * Permission to use, copy, modify, distribute and sell this software
  35  * and its documentation for any purpose is hereby granted without fee,
  36  * provided that the above copyright notice appear in all copies and
  37  * that both that copyright notice and this permission notice appear
  38  * in supporting documentation.  Silicon Graphics makes no
  39  * representations about the suitability of this software for any
  40  * purpose.  It is provided "as is" without express or implied warranty.
  41  *
  42  *
  43  * Copyright (c) 1994
  44  * Hewlett-Packard Company
  45  *
  46  * Permission to use, copy, modify, distribute and sell this software
  47  * and its documentation for any purpose is hereby granted without fee,
  48  * provided that the above copyright notice appear in all copies and
  49  * that both that copyright notice and this permission notice appear
  50  * in supporting documentation.  Hewlett-Packard Company makes no
  51  * representations about the suitability of this software for any
  52  * purpose.  It is provided "as is" without express or implied warranty.
  53  *
  54  */
  55
  56 /** @file ext/stl_hash_fun.h
  57  *  This file is a GNU extension to the Standard C++ Library (possibly
  58  *  containing extensions from the HP/SGI STL subset).  You should only
  59  *  include this header if you are using GCC 3 or later.
  60  */
  61
  62 #ifndef _CPP_BITS_STL_HASH_FUN_H
  63 #define _CPP_BITS_STL_HASH_FUN_H 1
  64
  65 #include <cstddef>
  66
  67 namespace __gnu_cxx
  68 {
  69 using std::size_t;
  70
  71 template <class _Key> struct hash { };
  72
  73 inline size_t __stl_hash_string(const char* __s)
  74 {
  75   unsigned long __h = 0;
  76   for ( ; *__s; ++__s)
  77     __h = 5*__h + *__s;
  78
  79   return size_t(__h);
  80 }
  81
  82 template<> struct hash<char*>
  83 {
  84   size_t operator()(const char* __s) const { return __stl_hash_string(__s); }
  85 };
  86
  87 template<> struct hash<const char*>
  88 {
  89   size_t operator()(const char* __s) const { return __stl_hash_string(__s); }
  90 };
  91
  92 template<> struct hash<char> {
  93   size_t operator()(char __x) const { return __x; }
  94 };
  95 template<> struct hash<unsigned char> {
  96   size_t operator()(unsigned char __x) const { return __x; }
  97 };
  98 template<> struct hash<signed char> {
  99   size_t operator()(unsigned char __x) const { return __x; }
 100 };
 101 template<> struct hash<short> {
 102   size_t operator()(short __x) const { return __x; }
 103 };
 104 template<> struct hash<unsigned short> {
 105   size_t operator()(unsigned short __x) const { return __x; }
 106 };
 107 template<> struct hash<int> {
 108   size_t operator()(int __x) const { return __x; }
 109 };
 110 template<> struct hash<unsigned int> {
 111   size_t operator()(unsigned int __x) const { return __x; }
 112 };
 113 template<> struct hash<long> {
 114   size_t operator()(long __x) const { return __x; }
 115 };
 116 template<> struct hash<unsigned long> {
 117   size_t operator()(unsigned long __x) const { return __x; }
 118 };
 119
 120 } // namespace __gnu_cxx
 121
 122 #endif /* _CPP_BITS_STL_HASH_FUN_H */
 123
 124 // Local Variables:
 125 // mode:C++
 126 // End: