1  // 'struct hash' from SGI -*- C++ -*-
       2  
       3  // Copyright (C) 2001-2023 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 _BACKWARD_HASH_FUN_H
      57  #define _BACKWARD_HASH_FUN_H 1
      58  
      59  #include <bits/c++config.h>
      60  
      61  namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
      62  {
      63  _GLIBCXX_BEGIN_NAMESPACE_VERSION
      64  
      65    using std::size_t;
      66  
      67    template<class _Key>
      68      struct hash { };
      69  
      70    inline size_t
      71    __stl_hash_string(const char* __s)
      72    {
      73      unsigned long __h = 0;
      74      for ( ; *__s; ++__s)
      75        __h = 5 * __h + *__s;
      76      return size_t(__h);
      77    }
      78  
      79    template<>
      80      struct hash<char*>
      81      {
      82        size_t
      83        operator()(const char* __s) const
      84        { return __stl_hash_string(__s); }
      85      };
      86  
      87    template<>
      88      struct hash<const char*>
      89      {
      90        size_t
      91        operator()(const char* __s) const
      92        { return __stl_hash_string(__s); }
      93      };
      94  
      95    template<>
      96      struct hash<char>
      97      { 
      98        size_t
      99        operator()(char __x) const
     100        { return __x; }
     101      };
     102  
     103    template<>
     104      struct hash<unsigned char>
     105      { 
     106        size_t
     107        operator()(unsigned char __x) const
     108        { return __x; }
     109      };
     110  
     111    template<>
     112      struct hash<signed char>
     113      {
     114        size_t
     115        operator()(unsigned char __x) const
     116        { return __x; }
     117      };
     118  
     119    template<>
     120      struct hash<short>
     121      {
     122        size_t
     123        operator()(short __x) const
     124        { return __x; }
     125      };
     126  
     127    template<>
     128      struct hash<unsigned short>
     129      {
     130        size_t
     131        operator()(unsigned short __x) const
     132        { return __x; }
     133      };
     134  
     135    template<>
     136      struct hash<int>
     137      { 
     138        size_t 
     139        operator()(int __x) const 
     140        { return __x; }
     141      };
     142  
     143    template<>
     144      struct hash<unsigned int>
     145      { 
     146        size_t
     147        operator()(unsigned int __x) const
     148        { return __x; }
     149      };
     150  
     151    template<>
     152      struct hash<long>
     153      {
     154        size_t
     155        operator()(long __x) const
     156        { return __x; }
     157      };
     158  
     159    template<>
     160      struct hash<unsigned long>
     161      {
     162        size_t
     163        operator()(unsigned long __x) const
     164        { return __x; }
     165      };
     166  
     167  _GLIBCXX_END_NAMESPACE_VERSION
     168  } // namespace
     169  
     170  #endif