1 // Stream iterators
2
3 // Copyright (C) 2001, 2004, 2005 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 2, 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 // You should have received a copy of the GNU General Public License along
17 // with this library; see the file COPYING. If not, write to the Free
18 // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
19 // USA.
20
21 // As a special exception, you may use this file as part of a free software
22 // library without restriction. Specifically, if other files instantiate
23 // templates or use macros or inline functions from this file, or you compile
24 // this file and link it with other files to produce an executable, this
25 // file does not by itself cause the resulting executable to be covered by
26 // the GNU General Public License. This exception does not however
27 // invalidate any other reasons why the executable file might be covered by
28 // the GNU General Public License.
29
30 /** @file stream_iterator.h
31 * This is an internal header file, included by other library headers.
32 * You should not attempt to use it directly.
33 */
34
35 #ifndef _STREAM_ITERATOR_H
36 #define _STREAM_ITERATOR_H 1
37
38 #pragma GCC system_header
39
40 #include <debug/debug.h>
41
_GLIBCXX_BEGIN_NAMESPACE(std)42 _GLIBCXX_BEGIN_NAMESPACE(std)
43
44 /// Provides input iterator semantics for streams.
45 template<typename _Tp, typename _CharT = char,
46 typename _Traits = char_traits<_CharT>, typename _Dist = ptrdiff_t>
47 class istream_iterator
48 : public iterator<input_iterator_tag, _Tp, _Dist, const _Tp*, const _Tp&>
49 {
50 public:
51 typedef _CharT char_type;
52 typedef _Traits traits_type;
53 typedef basic_istream<_CharT, _Traits> istream_type;
54
55 private:
56 istream_type* _M_stream;
57 _Tp _M_value;
58 bool _M_ok;
59
60 public:
61 /// Construct end of input stream iterator.
62 istream_iterator()
63 : _M_stream(0), _M_value(), _M_ok(false) {}
64
65 /// Construct start of input stream iterator.
66 istream_iterator(istream_type& __s)
67 : _M_stream(&__s)
68 { _M_read(); }
69
70 istream_iterator(const istream_iterator& __obj)
71 : _M_stream(__obj._M_stream), _M_value(__obj._M_value),
72 _M_ok(__obj._M_ok)
73 { }
74
75 const _Tp&
76 operator*() const
77 {
78 __glibcxx_requires_cond(_M_ok,
79 _M_message(__gnu_debug::__msg_deref_istream)
80 ._M_iterator(*this));
81 return _M_value;
82 }
83
84 const _Tp*
85 operator->() const { return &(operator*()); }
86
87 istream_iterator&
88 operator++()
89 {
90 __glibcxx_requires_cond(_M_ok,
91 _M_message(__gnu_debug::__msg_inc_istream)
92 ._M_iterator(*this));
93 _M_read();
94 return *this;
95 }
96
97 istream_iterator
98 operator++(int)
99 {
100 __glibcxx_requires_cond(_M_ok,
101 _M_message(__gnu_debug::__msg_inc_istream)
102 ._M_iterator(*this));
103 istream_iterator __tmp = *this;
104 _M_read();
105 return __tmp;
106 }
107
108 bool
109 _M_equal(const istream_iterator& __x) const
110 { return (_M_ok == __x._M_ok) && (!_M_ok || _M_stream == __x._M_stream); }
111
112 private:
113 void
114 _M_read()
115 {
116 _M_ok = (_M_stream && *_M_stream) ? true : false;
117 if (_M_ok)
118 {
119 *_M_stream >> _M_value;
120 _M_ok = *_M_stream ? true : false;
121 }
122 }
123 };
124
125 /// Return true if x and y are both end or not end, or x and y are the same.
126 template<typename _Tp, typename _CharT, typename _Traits, typename _Dist>
127 inline bool
128 operator==(const istream_iterator<_Tp, _CharT, _Traits, _Dist>& __x,
129 const istream_iterator<_Tp, _CharT, _Traits, _Dist>& __y)
130 { return __x._M_equal(__y); }
131
132 /// Return false if x and y are both end or not end, or x and y are the same.
133 template <class _Tp, class _CharT, class _Traits, class _Dist>
134 inline bool
135 operator!=(const istream_iterator<_Tp, _CharT, _Traits, _Dist>& __x,
136 const istream_iterator<_Tp, _CharT, _Traits, _Dist>& __y)
137 { return !__x._M_equal(__y); }
138
139 /**
140 * @brief Provides output iterator semantics for streams.
141 *
142 * This class provides an iterator to write to an ostream. The type Tp is
143 * the only type written by this iterator and there must be an
144 * operator<<(Tp) defined.
145 *
146 * @param Tp The type to write to the ostream.
147 * @param CharT The ostream char_type.
148 * @param Traits The ostream char_traits.
149 */
150 template<typename _Tp, typename _CharT = char,
151 typename _Traits = char_traits<_CharT> >
152 class ostream_iterator
153 : public iterator<output_iterator_tag, void, void, void, void>
154 {
155 public:
156 //@{
157 /// Public typedef
158 typedef _CharT char_type;
159 typedef _Traits traits_type;
160 typedef basic_ostream<_CharT, _Traits> ostream_type;
161 //@}
162
163 private:
164 ostream_type* _M_stream;
165 const _CharT* _M_string;
166
167 public:
168 /// Construct from an ostream.
ostream_iterator(ostream_type & __s)169 ostream_iterator(ostream_type& __s) : _M_stream(&__s), _M_string(0) {}
170
171 /**
172 * Construct from an ostream.
173 *
174 * The delimiter string @a c is written to the stream after every Tp
175 * written to the stream. The delimiter is not copied, and thus must
176 * not be destroyed while this iterator is in use.
177 *
178 * @param s Underlying ostream to write to.
179 * @param c CharT delimiter string to insert.
180 */
ostream_iterator(ostream_type & __s,const _CharT * __c)181 ostream_iterator(ostream_type& __s, const _CharT* __c)
182 : _M_stream(&__s), _M_string(__c) { }
183
184 /// Copy constructor.
ostream_iterator(const ostream_iterator & __obj)185 ostream_iterator(const ostream_iterator& __obj)
186 : _M_stream(__obj._M_stream), _M_string(__obj._M_string) { }
187
188 /// Writes @a value to underlying ostream using operator<<. If
189 /// constructed with delimiter string, writes delimiter to ostream.
190 ostream_iterator&
191 operator=(const _Tp& __value)
192 {
193 __glibcxx_requires_cond(_M_stream != 0,
194 _M_message(__gnu_debug::__msg_output_ostream)
195 ._M_iterator(*this));
196 *_M_stream << __value;
197 if (_M_string) *_M_stream << _M_string;
198 return *this;
199 }
200
201 ostream_iterator&
202 operator*()
203 { return *this; }
204
205 ostream_iterator&
206 operator++()
207 { return *this; }
208
209 ostream_iterator&
210 operator++(int)
211 { return *this; }
212 };
213
214 _GLIBCXX_END_NAMESPACE
215
216 #endif
217