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 */
57struct 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
83int
84main()
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
112