libstdc++-v3/testsuite/util/hash_fn/limit_string_hash_fn.hpp

   1 // -*- C++ -*-
   2
   3 // Copyright (C) 2005, 2006 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 terms
   7 // of the GNU General Public License as published by the Free Software
   8 // Foundation; either version 2, or (at your option) any later
   9 // version.
  10
  11 // This library is distributed in the hope that it will be useful, but
  12 // WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 // General Public License for more details.
  15
  16 // You should have received a copy of the GNU General Public License
  17 // along with this library; see the file COPYING.  If not, write to
  18 // the Free Software Foundation, 59 Temple Place - Suite 330, Boston,
  19 // MA 02111-1307, USA.
  20
  21 // As a special exception, you may use this file as part of a free
  22 // software library without restriction.  Specifically, if other files
  23 // instantiate templates or use macros or inline functions from this
  24 // file, or you compile this file and link it with other files to
  25 // produce an executable, this file does not by itself cause the
  26 // resulting executable to be covered by the GNU General Public
  27 // License.  This exception does not however invalidate any other
  28 // reasons why the executable file might be covered by the GNU General
  29 // Public License.
  30
  31 // Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL.
  32
  33 // Permission to use, copy, modify, sell, and distribute this software
  34 // is hereby granted without fee, provided that the above copyright
  35 // notice appears in all copies, and that both that copyright notice
  36 // and this permission notice appear in supporting documentation. None
  37 // of the above authors, nor IBM Haifa Research Laboratories, make any
  38 // representation about the suitability of this software for any
  39 // purpose. It is provided "as is" without express or implied
  40 // warranty.
  41
  42 /**
  43  * @file limit_string_hash_fn.hpp
  44  * Contains a string hash function.
  45  */
  46
  47 #ifndef PB_DS_LIMIT_STRING_HASH_FN_HPP
  48 #define PB_DS_LIMIT_STRING_HASH_FN_HPP
  49
  50 #include <string>
  51
  52 namespace __gnu_pbds
  53 {
  54   namespace test
  55   {
  56     struct limit_string_hash_fn
  57     {
  58       static size_t _S_max;
  59
  60       inline size_t
  61       operator()(const std::string& r_str) const
  62       {
  63         size_t ret = 0;
  64         std::string::const_iterator b = r_str.begin();
  65         std::string::const_iterator e = r_str.end();
  66
  67         size_t i = 0;
  68         while (b != e&&  i < _S_max)
  69           {
  70             ret *= 5;
  71             ret += static_cast<size_t>(*(b++));
  72           }
  73         return ret;
  74       }
  75     };
  76
  77     size_t limit_string_hash_fn::_S_max;
  78
  79   } // namespace test
  80 } // namespace __gnu_pbds
  81
  82 #endif