# hash_fun.h

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    00001 // 'struct hash' from SGI -*- C++ -*-
    00002
    00003 // Copyright (C) 2001, 2002, 2003, 2004, 2005 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 2, 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 // You should have received a copy of the GNU General Public License along
    00017 // with this library; see the file COPYING.  If not, write to the Free
    00018 // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
    00019 // USA.
    00020
    00021 // As a special exception, you may use this file as part of a free software
    00022 // library without restriction.  Specifically, if other files instantiate
    00023 // templates or use macros or inline functions from this file, or you compile
    00024 // this file and link it with other files to produce an executable, this
    00025 // file does not by itself cause the resulting executable to be covered by
    00026 // the GNU General Public License.  This exception does not however
    00027 // invalidate any other reasons why the executable file might be covered by
    00028 // the GNU General Public License.
    00029
    00030 /*
    00031  * Copyright (c) 1996-1998
    00032  * Silicon Graphics Computer Systems, Inc.
    00033  *
    00034  * Permission to use, copy, modify, distribute and sell this software
    00035  * and its documentation for any purpose is hereby granted without fee,
    00036  * provided that the above copyright notice appear in all copies and
    00037  * that both that copyright notice and this permission notice appear
    00038  * in supporting documentation.  Silicon Graphics makes no
    00039  * representations about the suitability of this software for any
    00040  * purpose.  It is provided "as is" without express or implied warranty.
    00041  *
    00042  *
    00043  * Copyright (c) 1994
    00044  * Hewlett-Packard Company
    00045  *
    00046  * Permission to use, copy, modify, distribute and sell this software
    00047  * and its documentation for any purpose is hereby granted without fee,
    00048  * provided that the above copyright notice appear in all copies and
    00049  * that both that copyright notice and this permission notice appear
    00050  * in supporting documentation.  Hewlett-Packard Company makes no
    00051  * representations about the suitability of this software for any
    00052  * purpose.  It is provided "as is" without express or implied warranty.
    00053  *
    00054  */
    00055
    00056 /** @file ext/hash_fun.h
    00057  *  This file is a GNU extension to the Standard C++ Library (possibly
    00058  *  containing extensions from the HP/SGI STL subset).
    00059  */
    00060
    00061 #ifndef _HASH_FUN_H
    00062 #define _HASH_FUN_H 1
    00063
    00064 #include <cstddef>
    00065
    00066 _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
    00067
    00068   using std::size_t;
    00069
    00070   template<class _Key>
    00071     struct hash { };
    00072
    00073   inline size_t
    00074   __stl_hash_string(const char* __s)
    00075   {
    00076     unsigned long __h = 0;
    00077     for ( ; *__s; ++__s)
    00078       __h = 5 * __h + *__s;
    00079     return size_t(__h);
    00080   }
    00081
    00082   template<>
    00083     struct hash<char*>
    00084     {
    00085       size_t
    00086       operator()(const char* __s) const
    00087       { return __stl_hash_string(__s); }
    00088     };
    00089
    00090   template<>
    00091     struct hash<const char*>
    00092     {
    00093       size_t
    00094       operator()(const char* __s) const
    00095       { return __stl_hash_string(__s); }
    00096     };
    00097
    00098   template<>
    00099     struct hash<char>
    00100     {
    00101       size_t
    00102       operator()(char __x) const
    00103       { return __x; }
    00104     };
    00105
    00106   template<>
    00107     struct hash<unsigned char>
    00108     {
    00109       size_t
    00110       operator()(unsigned char __x) const
    00111       { return __x; }
    00112     };
    00113
    00114   template<>
    00115     struct hash<signed char>
    00116     {
    00117       size_t
    00118       operator()(unsigned char __x) const
    00119       { return __x; }
    00120     };
    00121
    00122   template<>
    00123     struct hash<short>
    00124     {
    00125       size_t
    00126       operator()(short __x) const
    00127       { return __x; }
    00128     };
    00129
    00130   template<>
    00131     struct hash<unsigned short>
    00132     {
    00133       size_t
    00134       operator()(unsigned short __x) const
    00135       { return __x; }
    00136     };
    00137
    00138   template<>
    00139     struct hash<int>
    00140     {
    00141       size_t
    00142       operator()(int __x) const
    00143       { return __x; }
    00144     };
    00145
    00146   template<>
    00147     struct hash<unsigned int>
    00148     {
    00149       size_t
    00150       operator()(unsigned int __x) const
    00151       { return __x; }
    00152     };
    00153
    00154   template<>
    00155     struct hash<long>
    00156     {
    00157       size_t
    00158       operator()(long __x) const
    00159       { return __x; }
    00160     };
    00161
    00162   template<>
    00163     struct hash<unsigned long>
    00164     {
    00165       size_t
    00166       operator()(unsigned long __x) const
    00167       { return __x; }
    00168     };
    00169
    00170 _GLIBCXX_END_NAMESPACE
    00171
    00172 #endif