1/*=============================================================================
2 Copyright (c) 2002 Juan Carlos Arevalo-Baeza
3 Copyright (c) 2002-2006 Hartmut Kaiser
4 Copyright (c) 2003 Giovanni Bajo
5 http://spirit.sourceforge.net/
6
7 Use, modification and distribution is subject to the Boost Software
8 License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
9 http://www.boost.org/LICENSE_1_0.txt)
10=============================================================================*/
11#ifndef BOOST_SPIRIT_CLASSIC_ITERATOR_IMPL_POSITION_ITERATOR_IPP
12#define BOOST_SPIRIT_CLASSIC_ITERATOR_IMPL_POSITION_ITERATOR_IPP
13
14#include <boost/config.hpp>
15#include <boost/iterator_adaptors.hpp>
16#include <boost/type_traits/add_const.hpp>
17#include <boost/mpl/if.hpp>
18#include <boost/type_traits/is_same.hpp>
19#include <boost/spirit/home/classic/core/nil.hpp> // for nil_t
20#include <iterator> // for std::iterator_traits
21
22namespace boost { namespace spirit {
23
24BOOST_SPIRIT_CLASSIC_NAMESPACE_BEGIN
25
26///////////////////////////////////////////////////////////////////////////////
27//
28// position_policy<file_position_without_column>
29//
30// Specialization to handle file_position_without_column. Only take care of
31// newlines since no column tracking is needed.
32//
33///////////////////////////////////////////////////////////////////////////////
34template <typename String>
35class position_policy<file_position_without_column_base<String> > {
36
37public:
38 void next_line(file_position_without_column_base<String>& pos)
39 {
40 ++pos.line;
41 }
42
43 void set_tab_chars(unsigned int /*chars*/){}
44 void next_char(file_position_without_column_base<String>& /*pos*/) {}
45 void tabulation(file_position_without_column_base<String>& /*pos*/) {}
46};
47
48///////////////////////////////////////////////////////////////////////////////
49//
50// position_policy<file_position>
51//
52// Specialization to handle file_position. Track characters and tabulation
53// to compute the current column correctly.
54//
55// Default tab size is 4. You can change this with the set_tabchars member
56// of position_iterator.
57//
58///////////////////////////////////////////////////////////////////////////////
59template <typename String>
60class position_policy<file_position_base<String> > {
61
62public:
63 position_policy()
64 : m_CharsPerTab(4)
65 {}
66
67 void next_line(file_position_base<String>& pos)
68 {
69 ++pos.line;
70 pos.column = 1;
71 }
72
73 void set_tab_chars(unsigned int chars)
74 {
75 m_CharsPerTab = chars;
76 }
77
78 void next_char(file_position_base<String>& pos)
79 {
80 ++pos.column;
81 }
82
83 void tabulation(file_position_base<String>& pos)
84 {
85 pos.column += m_CharsPerTab - (pos.column - 1) % m_CharsPerTab;
86 }
87
88private:
89 unsigned int m_CharsPerTab;
90};
91
92/* namespace boost::spirit { */ namespace iterator_ { namespace impl {
93
94template <typename T>
95struct make_const : boost::add_const<T>
96{};
97
98template <typename T>
99struct make_const<T&>
100{
101 typedef typename boost::add_const<T>::type& type;
102};
103
104///////////////////////////////////////////////////////////////////////////////
105//
106// position_iterator_base_generator
107//
108// Metafunction to generate the iterator type using boost::iterator_adaptors,
109// hiding all the metaprogramming thunking code in it. It is used
110// mainly to keep the public interface (position_iterator) cleanear.
111//
112///////////////////////////////////////////////////////////////////////////////
113template <typename MainIterT, typename ForwardIterT, typename PositionT>
114struct position_iterator_base_generator
115{
116private:
117 typedef std::iterator_traits<ForwardIterT> traits;
118 typedef typename traits::value_type value_type;
119 typedef typename traits::iterator_category iter_category_t;
120 typedef typename traits::reference reference;
121
122 // Position iterator is always a non-mutable iterator
123 typedef typename boost::add_const<value_type>::type const_value_type;
124
125public:
126 // Check if the MainIterT is nil. If it's nil, it means that the actual
127 // self type is position_iterator. Otherwise, it's a real type we
128 // must use
129 typedef typename boost::mpl::if_<
130 typename boost::is_same<MainIterT, nil_t>::type,
131 position_iterator<ForwardIterT, PositionT, nil_t>,
132 MainIterT
133 >::type main_iter_t;
134
135 typedef boost::iterator_adaptor<
136 main_iter_t,
137 ForwardIterT,
138 const_value_type,
139 boost::forward_traversal_tag,
140 typename make_const<reference>::type
141 > type;
142};
143
144}}
145
146BOOST_SPIRIT_CLASSIC_NAMESPACE_END
147
148}} /* namespace boost::spirit::iterator_::impl */
149
150#endif
151

source code of boost/libs/spirit/include/boost/spirit/home/classic/iterator/impl/position_iterator.ipp