libstdc++
stream_iterator.h
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1 // Stream iterators
2 
3 // Copyright (C) 2001, 2004, 2005, 2009, 2010 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>
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;
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.
69  : _M_stream(&__s)
70  { _M_read(); }
71 
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 
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 
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
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
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> >
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;
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.
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.
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 
204  operator*()
205  { return *this; }
206 
208  operator++()
209  { return *this; }
210 
212  operator++(int)
213  { return *this; }
214  };
215 
216  // @} group iterators
217 
218 _GLIBCXX_END_NAMESPACE_VERSION
219 } // namespace
220 
221 #endif