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

   1 // -*- C++ -*-
   2
   3 // Copyright (C) 2005-2021 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 3, 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 COPYING3.  If not see
  18 // <http://www.gnu.org/licenses/>.
  19
  20
  21 // Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL.
  22
  23 // Permission to use, copy, modify, sell, and distribute this software
  24 // is hereby granted without fee, provided that the above copyright
  25 // notice appears in all copies, and that both that copyright notice
  26 // and this permission notice appear in supporting documentation. None
  27 // of the above authors, nor IBM Haifa Research Laboratories, make any
  28 // representation about the suitability of this software for any
  29 // purpose. It is provided "as is" without express or implied
  30 // warranty.
  31
  32 /**
  33  * @file limit_string_hash_fn.hpp
  34  * Contains a string hash function.
  35  */
  36
  37 #ifndef PB_DS_LIMIT_STRING_HASH_FN_HPP
  38 #define PB_DS_LIMIT_STRING_HASH_FN_HPP
  39
  40 #include <string>
  41
  42 namespace __gnu_pbds
  43 {
  44   namespace test
  45   {
  46     struct limit_string_hash_fn
  47     {
  48       static size_t _S_max;
  49
  50       inline size_t
  51       operator()(const std::string& r_str) const
  52       {
  53         size_t ret = 0;
  54         std::string::const_iterator b = r_str.begin();
  55         std::string::const_iterator e = r_str.end();
  56
  57         size_t i = 0;
  58         while (b != e&&  i < _S_max)
  59           {
  60             ret *= 5;
  61             ret += static_cast<size_t>(*(b++));
  62           }
  63         return ret;
  64       }
  65     };
  66
  67     size_t limit_string_hash_fn::_S_max;
  68
  69   } // namespace test
  70 } // namespace __gnu_pbds
  71
  72 #endif