1// Stream iterators
2
3// Copyright (C) 2001-2019 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
37namespace 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(std::__addressof(__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#if __cplusplus >= 201103L
78 istream_iterator& operator=(const istream_iterator&) = default;
79#endif
80
81 const _Tp&
82 operator*() const
83 {
84 __glibcxx_requires_cond(_M_ok,
85 _M_message(__gnu_debug::__msg_deref_istream)
86 ._M_iterator(*this));
87 return _M_value;
88 }
89
90 const _Tp*
91 operator->() const { return std::__addressof((operator*())); }
92
93 istream_iterator&
94 operator++()
95 {
96 __glibcxx_requires_cond(_M_ok,
97 _M_message(__gnu_debug::__msg_inc_istream)
98 ._M_iterator(*this));
99 _M_read();
100 return *this;
101 }
102
103 istream_iterator
104 operator++(int)
105 {
106 __glibcxx_requires_cond(_M_ok,
107 _M_message(__gnu_debug::__msg_inc_istream)
108 ._M_iterator(*this));
109 istream_iterator __tmp = *this;
110 _M_read();
111 return __tmp;
112 }
113
114 bool
115 _M_equal(const istream_iterator& __x) const
116 { return (_M_ok == __x._M_ok) && (!_M_ok || _M_stream == __x._M_stream); }
117
118 private:
119 void
120 _M_read()
121 {
122 _M_ok = (_M_stream && *_M_stream) ? true : false;
123 if (_M_ok)
124 {
125 *_M_stream >> _M_value;
126 _M_ok = *_M_stream ? true : false;
127 }
128 }
129 };
130
131 /// Return true if x and y are both end or not end, or x and y are the same.
132 template<typename _Tp, typename _CharT, typename _Traits, typename _Dist>
133 inline bool
134 operator==(const istream_iterator<_Tp, _CharT, _Traits, _Dist>& __x,
135 const istream_iterator<_Tp, _CharT, _Traits, _Dist>& __y)
136 { return __x._M_equal(__y); }
137
138 /// Return false if x and y are both end or not end, or x and y are the same.
139 template <class _Tp, class _CharT, class _Traits, class _Dist>
140 inline bool
141 operator!=(const istream_iterator<_Tp, _CharT, _Traits, _Dist>& __x,
142 const istream_iterator<_Tp, _CharT, _Traits, _Dist>& __y)
143 { return !__x._M_equal(__y); }
144
145 /**
146 * @brief Provides output iterator semantics for streams.
147 *
148 * This class provides an iterator to write to an ostream. The type Tp is
149 * the only type written by this iterator and there must be an
150 * operator<<(Tp) defined.
151 *
152 * @tparam _Tp The type to write to the ostream.
153 * @tparam _CharT The ostream char_type.
154 * @tparam _Traits The ostream char_traits.
155 */
156 template<typename _Tp, typename _CharT = char,
157 typename _Traits = char_traits<_CharT> >
158 class ostream_iterator
159 : public iterator<output_iterator_tag, void, void, void, void>
160 {
161 public:
162 //@{
163 /// Public typedef
164 typedef _CharT char_type;
165 typedef _Traits traits_type;
166 typedef basic_ostream<_CharT, _Traits> ostream_type;
167 //@}
168
169 private:
170 ostream_type* _M_stream;
171 const _CharT* _M_string;
172
173 public:
174 /// Construct from an ostream.
175 ostream_iterator(ostream_type& __s)
176 : _M_stream(std::__addressof(__s)), _M_string(0) {}
177
178 /**
179 * Construct from an ostream.
180 *
181 * The delimiter string @a c is written to the stream after every Tp
182 * written to the stream. The delimiter is not copied, and thus must
183 * not be destroyed while this iterator is in use.
184 *
185 * @param __s Underlying ostream to write to.
186 * @param __c CharT delimiter string to insert.
187 */
188 ostream_iterator(ostream_type& __s, const _CharT* __c)
189 : _M_stream(&__s), _M_string(__c) { }
190
191 /// Copy constructor.
192 ostream_iterator(const ostream_iterator& __obj)
193 : _M_stream(__obj._M_stream), _M_string(__obj._M_string) { }
194
195#if __cplusplus >= 201103L
196 ostream_iterator& operator=(const ostream_iterator&) = default;
197#endif
198
199 /// Writes @a value to underlying ostream using operator<<. If
200 /// constructed with delimiter string, writes delimiter to ostream.
201 ostream_iterator&
202 operator=(const _Tp& __value)
203 {
204 __glibcxx_requires_cond(_M_stream != 0,
205 _M_message(__gnu_debug::__msg_output_ostream)
206 ._M_iterator(*this));
207 *_M_stream << __value;
208 if (_M_string) *_M_stream << _M_string;
209 return *this;
210 }
211
212 ostream_iterator&
213 operator*()
214 { return *this; }
215
216 ostream_iterator&
217 operator++()
218 { return *this; }
219
220 ostream_iterator&
221 operator++(int)
222 { return *this; }
223 };
224
225 // @} group iterators
226
227_GLIBCXX_END_NAMESPACE_VERSION
228} // namespace
229
230#endif
231