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
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.
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      */
181      ostream_iterator(ostream_type& __s, const _CharT* __c)
182      : _M_stream(&__s), _M_string(__c)  { }
183
184      /// Copy constructor.
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