gomp-20050608-branch/libstdc++-v3/testsuite/ext/pb_assoc/example/store_hash.cc

   1 // -*- C++ -*-
   2
   3 // Copyright (C) 2005 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, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
  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 // Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL.
  31
  32 // Permission to use, copy, modify, sell, and distribute this software
  33 // is hereby granted without fee, provided that the above copyright
  34 // notice appears in all copies, and that both that copyright notice and
  35 // this permission notice appear in supporting documentation. None of
  36 // the above authors, nor IBM Haifa Research Laboratories, make any
  37 // representation about the suitability of this software for any
  38 // purpose. It is provided "as is" without express or implied warranty.
  39
  40 /**
  41  * @file hash_mod_example.cpp
  42  * An example showing how to use cc_ht_map with alternative policies.
  43  */
  44
  45 // For cc_hash_assoc_cntnr.
  46 #include <ext/pb_assoc/assoc_cntnr.hpp>
  47 // For direct_mask_range_hashing and hash_standard_resize_policy.
  48 #include <ext/pb_assoc/hash_policy.hpp>
  49 // For unary_function, binary_function.
  50 #include <functional>
  51 // For string.
  52 #include <string>
  53
  54 /*
  55  * A string hash functor
  56  */
  57 struct string_hash : public std::unary_function<
  58   std::string,
  59                      size_t>
  60 {
  61   inline size_t
  62   operator()(std::string str) const
  63   {
  64     std::string::const_iterator b = str.begin();
  65
  66     std::string::const_iterator e = str.end();
  67
  68     size_t hash = 0;
  69
  70     while (b != e)
  71       {
  72         hash *= 5;
  73
  74         hash += static_cast<size_t>(*b);
  75
  76         ++b;
  77       }
  78
  79     return (hash);
  80   }
  81 };
  82
  83 int
  84 main()
  85 {
  86   /*
  87    * A collision-chaining hash table mapping strings to ints.
  88    */
  89   typedef
  90     pb_assoc::cc_hash_assoc_cntnr<
  91     std::string,
  92     int,
  93     // Hash function.
  94     string_hash,
  95     // Equivalence function.
  96     std::equal_to<
  97     std::string>,
  98     // Range hashing function.
  99     pb_assoc::direct_mask_range_hashing<>,
 100     // Resize policy.
 101     pb_assoc::hash_standard_resize_policy<>,
 102     // Store the hash value with each entry.
 103     true>
 104     map_t;
 105
 106   map_t h;
 107
 108   h["Hello, "] = 0;
 109   h["world"] = 1;
 110 }
 111