source: trunk/yat/utility/IteratorTraits.h @ 914

Last change on this file since 914 was 914, checked in by Peter, 14 years ago

refactoring add function in Averagers, refs #246

  • Property svn:eol-style set to native
  • Property svn:keywords set to Id
File size: 3.4 KB
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1#ifndef _theplu_yat_utility_iterator_traits_
2#define _theplu_yat_utility_iterator_traits_
3
4// $Id: IteratorTraits.h 914 2007-09-29 02:18:52Z 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  template <class U, class V>
59  struct weighted_iterator_traits<yat::utility::IteratorWeighted<U,V> > {
60    typedef weighted_type type;
61  };
62
63  // check (at compile time) that iterator is unweighted.
64  inline void check_iterator_is_unweighted(unweighted_type x){} 
65  template <class Iter>
66  void check_iterator_is_unweighted(Iter iter) 
67  {check_iterator_unweighted(typename weighted_iterator_traits<Iter>::type());}
68
69
70  /*
71    Function to be used to make compile-time decision how to return
72    data from an iterator separating two cases: weighted and
73    unweighted.
74
75    In this way unweighted iterators can be used in a weighted context.
76   */ 
77  // Peter, perhaps these should be templatized, but for now return
78  // type double is hard coded.
79  template <class Iter>
80  double iterator_traits_data(Iter iter)
81  { return iterator_traits_data(iter, weighted_iterator_traits<Iter>::type()); } 
82
83  template <class Iter>
84  double iterator_traits_data(Iter i, weighted_type)
85  { return i.data(); } 
86
87  template <class Iter>
88  double iterator_traits_data(Iter i, unweighted_type)
89  { return *i; } 
90
91  /*
92    Function to be used to make compile-time decision how to return
93    data from an iterator separating two cases: weighted and
94    unweighted.
95
96    In this way unweighted iterators can be used in a weighted context
97    and weight will be set to unity.
98   */ 
99  // Peter, perhaps these should be templatized, but for now return
100  // type double is hard coded.
101  template <class Iter>
102  double iterator_traits_weight(Iter iter)
103  { return iterator_traits_data(iter, weighted_iterator_traits<Iter>::type()); } 
104
105  template <class Iter>
106  double iterator_traits_weight(Iter i, weighted_type)
107  { return i.weight(); } 
108
109  template <class Iter>
110  double iterator_traits_weight(Iter i, unweighted_type)
111  { return 1.0; } 
112
113
114}}} // of namespace utility, yat, and theplu
115
116#endif
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