libstdc++

stream_iterator.h
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1 // Stream iterators
2
3 // Copyright (C) 2001-2013 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 3, 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 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
19
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 // <http://www.gnu.org/licenses/>.
24
25 /** @file bits/stream_iterator.h
26 * This is an internal header file, included by other library headers.
27 * Do not attempt to use it directly. @headername{iterator}
28 */
29
30 #ifndef _STREAM_ITERATOR_H
31 #define _STREAM_ITERATOR_H 1
32
33 #pragma GCC system_header
34
35 #include <debug/debug.h>
36
37 namespace std _GLIBCXX_VISIBILITY(default)
38 {
39 _GLIBCXX_BEGIN_NAMESPACE_VERSION
40
41 /**
42 * @addtogroup iterators
43 * @{
44 */
45
46 /// Provides input iterator semantics for streams.
47 template<typename _Tp, typename _CharT = char,
48 typename _Traits = char_traits<_CharT>, typename _Dist = ptrdiff_t>
49 class istream_iterator
50 : public iterator<input_iterator_tag, _Tp, _Dist, const _Tp*, const _Tp&>
51 {
52 public:
53 typedef _CharT char_type;
54 typedef _Traits traits_type;
55 typedef basic_istream<_CharT, _Traits> istream_type;
56
57 private:
58 istream_type* _M_stream;
59 _Tp _M_value;
60 bool _M_ok;
61
62 public:
63 /// Construct end of input stream iterator.
64 _GLIBCXX_CONSTEXPR istream_iterator()
65 : _M_stream(0), _M_value(), _M_ok(false) {}
66
67 /// Construct start of input stream iterator.
68 istream_iterator(istream_type& __s)
69 : _M_stream(&__s)
70 { _M_read(); }
71
72 istream_iterator(const istream_iterator& __obj)
73 : _M_stream(__obj._M_stream), _M_value(__obj._M_value),
74 _M_ok(__obj._M_ok)
75 { }
76
77 const _Tp&
78 operator*() const
79 {
80 __glibcxx_requires_cond(_M_ok,
81 _M_message(__gnu_debug::__msg_deref_istream)
82 ._M_iterator(*this));
83 return _M_value;
84 }
85
86 const _Tp*
87 operator->() const { return &(operator*()); }
88
89 istream_iterator&
90 operator++()
91 {
92 __glibcxx_requires_cond(_M_ok,
93 _M_message(__gnu_debug::__msg_inc_istream)
94 ._M_iterator(*this));
95 _M_read();
96 return *this;
97 }
98
99 istream_iterator
100 operator++(int)
101 {
102 __glibcxx_requires_cond(_M_ok,
103 _M_message(__gnu_debug::__msg_inc_istream)
104 ._M_iterator(*this));
105 istream_iterator __tmp = *this;
106 _M_read();
107 return __tmp;
108 }
109
110 bool
111 _M_equal(const istream_iterator& __x) const
112 { return (_M_ok == __x._M_ok) && (!_M_ok || _M_stream == __x._M_stream); }
113
114 private:
115 void
116 _M_read()
117 {
118 _M_ok = (_M_stream && *_M_stream) ? true : false;
119 if (_M_ok)
120 {
121 *_M_stream >> _M_value;
122 _M_ok = *_M_stream ? true : false;
123 }
124 }
125 };
126
127 /// Return true if x and y are both end or not end, or x and y are the same.
128 template<typename _Tp, typename _CharT, typename _Traits, typename _Dist>
129 inline bool
130 operator==(const istream_iterator<_Tp, _CharT, _Traits, _Dist>& __x,
131 const istream_iterator<_Tp, _CharT, _Traits, _Dist>& __y)
132 { return __x._M_equal(__y); }
133
134 /// Return false if x and y are both end or not end, or x and y are the same.
135 template <class _Tp, class _CharT, class _Traits, class _Dist>
136 inline bool
137 operator!=(const istream_iterator<_Tp, _CharT, _Traits, _Dist>& __x,
138 const istream_iterator<_Tp, _CharT, _Traits, _Dist>& __y)
139 { return !__x._M_equal(__y); }
140
141 /**
142 * @brief Provides output iterator semantics for streams.
143 *
144 * This class provides an iterator to write to an ostream. The type Tp is
145 * the only type written by this iterator and there must be an
146 * operator<<(Tp) defined.
147 *
148 * @tparam _Tp The type to write to the ostream.
149 * @tparam _CharT The ostream char_type.
150 * @tparam _Traits The ostream char_traits.
151 */
152 template<typename _Tp, typename _CharT = char,
153 typename _Traits = char_traits<_CharT> >
154 class ostream_iterator
155 : public iterator<output_iterator_tag, void, void, void, void>
156 {
157 public:
158 //@{
159 /// Public typedef
160 typedef _CharT char_type;
161 typedef _Traits traits_type;
162 typedef basic_ostream<_CharT, _Traits> ostream_type;
163 //@}
164
165 private:
166 ostream_type* _M_stream;
167 const _CharT* _M_string;
168
169 public:
170 /// Construct from an ostream.
171 ostream_iterator(ostream_type& __s) : _M_stream(&__s), _M_string(0) {}
172
173 /**
174 * Construct from an ostream.
175 *
176 * The delimiter string @a c is written to the stream after every Tp
177 * written to the stream. The delimiter is not copied, and thus must
178 * not be destroyed while this iterator is in use.
179 *
180 * @param __s Underlying ostream to write to.
181 * @param __c CharT delimiter string to insert.
182 */
183 ostream_iterator(ostream_type& __s, const _CharT* __c)
184 : _M_stream(&__s), _M_string(__c) { }
185
186 /// Copy constructor.
187 ostream_iterator(const ostream_iterator& __obj)
188 : _M_stream(__obj._M_stream), _M_string(__obj._M_string) { }
189
190 /// Writes @a value to underlying ostream using operator<<. If
191 /// constructed with delimiter string, writes delimiter to ostream.
192 ostream_iterator&
193 operator=(const _Tp& __value)
194 {
195 __glibcxx_requires_cond(_M_stream != 0,
196 _M_message(__gnu_debug::__msg_output_ostream)
197 ._M_iterator(*this));
198 *_M_stream << __value;
199 if (_M_string) *_M_stream << _M_string;
200 return *this;
201 }
202
203 ostream_iterator&
204 operator*()
205 { return *this; }
206
207 ostream_iterator&
208 operator++()
209 { return *this; }
210
211 ostream_iterator&
212 operator++(int)
213 { return *this; }
214 };
215
216 // @} group iterators
217
218 _GLIBCXX_END_NAMESPACE_VERSION
219 } // namespace
220
221 #endif