source: trunk/yat/utility/iterator_traits.h @ 966

Last change on this file since 966 was 966, checked in by Peter, 14 years ago

fixing some doxygen warnings

  • Property svn:eol-style set to native
  • Property svn:keywords set to Id
File size: 5.2 KB
Line 
1#ifndef _theplu_yat_utility_iterator_traits_
2#define _theplu_yat_utility_iterator_traits_
3
4// $Id: iterator_traits.h 966 2007-10-11 17:01:01Z peter $
5
6/*
7  Copyright (C) 2007 Peter Johansson
8
9  This file is part of the yat library, http://trac.thep.lu.se/trac/yat
10
11  The yat library is free software; you can redistribute it and/or
12  modify it under the terms of the GNU General Public License as
13  published by the Free Software Foundation; either version 2 of the
14  License, or (at your option) any later version.
15
16  The yat library is distributed in the hope that it will be useful,
17  but WITHOUT ANY WARRANTY; without even the implied warranty of
18  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19  General Public License for more details.
20
21  You should have received a copy of the GNU General Public License
22  along with this program; if not, write to the Free Software
23  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
24  02111-1307, USA.
25*/
26
27#include "yat/utility/IteratorWeighted.h"
28
29namespace theplu {
30namespace yat {
31namespace utility {
32
33  /**
34    Struct to be used to make compile-time decision that Iterator is
35    unweighted, which is the default.
36   */ 
37  struct unweighted_type {
38    typedef unweighted_type type;
39  };
40   
41  /**
42    Struct to be used to make compile-time decision that Iterator is
43    weighted. Some algorithms come in also in a weighted version in
44    this tag could be used to decide on using them (rather than
45    unweighted cousin).
46   */ 
47  struct weighted_type {
48    typedef weighted_type type;
49  };
50
51  /// All iterators should default to unweighted type ...
52  template <class T>
53  struct weighted_iterator_traits {
54    typedef unweighted_type type;
55  };
56
57  /// but specialized to return weighted type for some things
58  //
59  // if you add a new weighted iterator, add a new specialization like
60  // this one.
61  template <class U, class V>
62  struct weighted_iterator_traits<yat::utility::IteratorWeighted<U,V> > {
63    typedef weighted_type type;
64  };
65
66
67
68  /**
69    Metafunction that works on a pair weighted-unweighted types and
70    return weighted_type. The metafunction is specialized for
71    unweighted unweighted in which case unweighted is returned.
72   */
73  template <class T1, class T2>
74  struct unweighted_type_and {
75    typedef weighted_type type;
76  };
77
78  /**
79    Specialization that sets type to be unweighted when both arguments
80    are unweighted
81   */
82  template <>
83  struct unweighted_type_and<unweighted_type, unweighted_type> {
84    typedef unweighted_type type;
85  };
86
87  /**
88    struct used to determine if a pair of iterators should be treated
89    as weighted. If both iterators are unweighted, type is set to
90    unweighted else weighted.
91  */
92  template <class T1, class T2>
93  struct weighted_if_any2 {
94    typedef typename weighted_iterator_traits<T1>::type w_type1;
95    typedef typename weighted_iterator_traits<T2>::type w_type2;
96    typedef typename unweighted_type_and<w_type1, w_type2>::type type;
97  };
98
99  /**
100    Same as weighted_iterator_traits2 but for 3 arguments.
101   */
102  template <class T1, class T2, class T3>
103  struct weighted_if_any3 {
104    typedef typename weighted_if_any2<T1, T2>::type tmp;
105    typedef typename weighted_iterator_traits<T3>::type w_type3;
106    typedef typename unweighted_type_and<tmp, w_type3>::type type;
107  };
108
109  /// check (at compile time) that iterator is unweighted.
110  inline void check_iterator_is_unweighted(unweighted_type x){} 
111
112  /**
113     check (at compile time) that iterator \a iter is unweighted. This
114     function is strictly not needed, but exists only for convenience.
115   */
116  template <class Iter>
117  void check_iterator_is_unweighted(Iter iter) 
118  { check_iterator_is_unweighted(typename 
119                                 weighted_iterator_traits<Iter>::type());
120  }
121
122
123  /**
124    Function to be used to make compile-time decision how to return
125    data from an iterator separating two cases: weighted and
126    unweighted.
127
128    In this way unweighted iterators can be used in a weighted context.
129   */ 
130  // Peter, perhaps these should be templatized, but for now return
131  // type double is hard coded.
132  template <class Iter>
133  double iterator_traits_data(Iter iter)
134  { return iterator_traits_data(iter, typename 
135                                weighted_iterator_traits<Iter>::type()); } 
136
137  /**
138     \return data for weighted iterator
139   */
140  template <class Iter>
141  double iterator_traits_data(Iter i, weighted_type)
142  { return i.data(); } 
143
144  /**
145     \return data for unweighted data
146   */
147  template <class Iter>
148  double iterator_traits_data(Iter i, unweighted_type)
149  { return *i; } 
150
151  /**
152    Function to be used to make compile-time decision how to return
153    data from an iterator separating two cases: weighted and
154    unweighted.
155
156    In this way unweighted iterators can be used in a weighted context
157    and weight will be set to unity.
158   */ 
159  // Peter, perhaps these should be templatized, but for now return
160  // type double is hard coded.
161  template <class Iter>
162  double iterator_traits_weight(Iter iter)
163  { return iterator_traits_weight(iter, typename 
164                                  weighted_iterator_traits<Iter>::type()); } 
165
166  /**
167     \return weight for weighted iterator
168   */
169  template <class Iter>
170  double iterator_traits_weight(Iter i, weighted_type)
171  { return i.weight(); } 
172
173  /**
174     \return weight for unweighted iterator
175   */
176  template <class Iter>
177  double iterator_traits_weight(Iter i, unweighted_type)
178  { return 1.0; } 
179
180
181}}} // of namespace utility, yat, and theplu
182
183#endif
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