# stream_iterator.h

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    00001 // Stream iterators
    00002
    00003 // Copyright (C) 2001, 2004 Free Software Foundation, Inc.
    00004 //
    00005 // This file is part of the GNU ISO C++ Library.  This library is free
    00006 // software; you can redistribute it and/or modify it under the
    00007 // terms of the GNU General Public License as published by the
    00008 // Free Software Foundation; either version 2, or (at your option)
    00009 // any later version.
    00010
    00011 // This library is distributed in the hope that it will be useful,
    00012 // but WITHOUT ANY WARRANTY; without even the implied warranty of
    00013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    00014 // GNU General Public License for more details.
    00015
    00016 // You should have received a copy of the GNU General Public License along
    00017 // with this library; see the file COPYING.  If not, write to the Free
    00018 // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
    00019 // USA.
    00020
    00021 // As a special exception, you may use this file as part of a free software
    00022 // library without restriction.  Specifically, if other files instantiate
    00023 // templates or use macros or inline functions from this file, or you compile
    00024 // this file and link it with other files to produce an executable, this
    00025 // file does not by itself cause the resulting executable to be covered by
    00026 // the GNU General Public License.  This exception does not however
    00027 // invalidate any other reasons why the executable file might be covered by
    00028 // the GNU General Public License.
    00029
    00030 /** @file stream_iterator.h
    00031  *  This is an internal header file, included by other library headers.
    00032  *  You should not attempt to use it directly.
    00033  */
    00034
    00035 #ifndef _STREAM_ITERATOR_H
    00036 #define _STREAM_ITERATOR_H 1
    00037
    00038 #pragma GCC system_header
    00039
    00040 #include <debug/debug.h>
    00041
    00042 namespace std
    00043 {
    00044   /// Provides input iterator semantics for streams.
    00045   template<typename _Tp, typename _CharT = char,
    00046            typename _Traits = char_traits<_CharT>, typename _Dist = ptrdiff_t>
    00047     class istream_iterator
    00048     : public iterator<input_iterator_tag, _Tp, _Dist, const _Tp*, const _Tp&>
    00049     {
    00050     public:
    00051       typedef _CharT                         char_type;
    00052       typedef _Traits                        traits_type;
    00053       typedef basic_istream<_CharT, _Traits> istream_type;
    00054
    00055     private:
    00056       istream_type* _M_stream;
    00057       _Tp       _M_value;
    00058       bool      _M_ok;
    00059
    00060     public:
    00061       ///  Construct end of input stream iterator.
    00062       istream_iterator()
    00063       : _M_stream(0), _M_ok(false) {}
    00064
    00065       ///  Construct start of input stream iterator.
    00066       istream_iterator(istream_type& __s)
    00067       : _M_stream(&__s)
    00068       { _M_read(); }
    00069
    00070       istream_iterator(const istream_iterator& __obj)
    00071       : _M_stream(__obj._M_stream), _M_value(__obj._M_value),
    00072         _M_ok(__obj._M_ok)
    00073       { }
    00074
    00075       const _Tp&
    00076       operator*() const
    00077       {
    00078     __glibcxx_requires_cond(_M_ok,
    00079                 _M_message(__gnu_debug::__msg_deref_istream)
    00080                 ._M_iterator(*this));
    00081     return _M_value;
    00082       }
    00083
    00084       const _Tp*
    00085       operator->() const { return &(operator*()); }
    00086
    00087       istream_iterator&
    00088       operator++()
    00089       {
    00090     __glibcxx_requires_cond(_M_ok,
    00091                 _M_message(__gnu_debug::__msg_inc_istream)
    00092                 ._M_iterator(*this));
    00093     _M_read();
    00094     return *this;
    00095       }
    00096
    00097       istream_iterator
    00098       operator++(int)
    00099       {
    00100     __glibcxx_requires_cond(_M_ok,
    00101                 _M_message(__gnu_debug::__msg_inc_istream)
    00102                 ._M_iterator(*this));
    00103     istream_iterator __tmp = *this;
    00104     _M_read();
    00105     return __tmp;
    00106       }
    00107
    00108       bool
    00109       _M_equal(const istream_iterator& __x) const
    00110       { return (_M_ok == __x._M_ok) && (!_M_ok || _M_stream == __x._M_stream); }
    00111
    00112     private:
    00113       void
    00114       _M_read()
    00115       {
    00116     _M_ok = (_M_stream && *_M_stream) ? true : false;
    00117     if (_M_ok)
    00118       {
    00119         *_M_stream >> _M_value;
    00120         _M_ok = *_M_stream ? true : false;
    00121       }
    00122       }
    00123     };
    00124
    00125   ///  Return true if x and y are both end or not end, or x and y are the same.
    00126   template<typename _Tp, typename _CharT, typename _Traits, typename _Dist>
    00127     inline bool
    00128     operator==(const istream_iterator<_Tp, _CharT, _Traits, _Dist>& __x,
    00129            const istream_iterator<_Tp, _CharT, _Traits, _Dist>& __y)
    00130     { return __x._M_equal(__y); }
    00131
    00132   ///  Return false if x and y are both end or not end, or x and y are the same.
    00133   template <class _Tp, class _CharT, class _Traits, class _Dist>
    00134     inline bool
    00135     operator!=(const istream_iterator<_Tp, _CharT, _Traits, _Dist>& __x,
    00136            const istream_iterator<_Tp, _CharT, _Traits, _Dist>& __y)
    00137     { return !__x._M_equal(__y); }
    00138
    00139   /**
    00140    *  @brief  Provides output iterator semantics for streams.
    00141    *
    00142    *  This class provides an iterator to write to an ostream.  The type Tp is
    00143    *  the only type written by this iterator and there must be an
    00144    *  operator<<(Tp) defined.
    00145    *
    00146    *  @param  Tp  The type to write to the ostream.
    00147    *  @param  CharT  The ostream char_type.
    00148    *  @param  Traits  The ostream char_traits.
    00149   */
    00150   template<typename _Tp, typename _CharT = char,
    00151            typename _Traits = char_traits<_CharT> >
    00152     class ostream_iterator
    00153     : public iterator<output_iterator_tag, void, void, void, void>
    00154     {
    00155     public:
    00156       //@{
    00157       /// Public typedef
    00158       typedef _CharT                         char_type;
    00159       typedef _Traits                        traits_type;
    00160       typedef basic_ostream<_CharT, _Traits> ostream_type;
    00161       //@}
    00162
    00163     private:
    00164       ostream_type* _M_stream;
    00165       const _CharT* _M_string;
    00166
    00167     public:
    00168       /// Construct from an ostream.
    00169       ostream_iterator(ostream_type& __s) : _M_stream(&__s), _M_string(0) {}
    00170
    00171       /**
    00172        *  Construct from an ostream.
    00173        *
    00174        *  The delimiter string @a c is written to the stream after every Tp
    00175        *  written to the stream.  The delimiter is not copied, and thus must
    00176        *  not be destroyed while this iterator is in use.
    00177        *
    00178        *  @param  s  Underlying ostream to write to.
    00179        *  @param  c  CharT delimiter string to insert.
    00180       */
    00181       ostream_iterator(ostream_type& __s, const _CharT* __c)
    00182       : _M_stream(&__s), _M_string(__c)  { }
    00183
    00184       /// Copy constructor.
    00185       ostream_iterator(const ostream_iterator& __obj)
    00186       : _M_stream(__obj._M_stream), _M_string(__obj._M_string)  { }
    00187
    00188       /// Writes @a value to underlying ostream using operator<<.  If
    00189       /// constructed with delimiter string, writes delimiter to ostream.
    00190       ostream_iterator&
    00191       operator=(const _Tp& __value)
    00192       {
    00193     __glibcxx_requires_cond(_M_stream != 0,
    00194                 _M_message(__gnu_debug::__msg_output_ostream)
    00195                 ._M_iterator(*this));
    00196     *_M_stream << __value;
    00197     if (_M_string) *_M_stream << _M_string;
    00198     return *this;
    00199       }
    00200
    00201       ostream_iterator&
    00202       operator*()
    00203       { return *this; }
    00204
    00205       ostream_iterator&
    00206       operator++()
    00207       { return *this; }
    00208
    00209       ostream_iterator&
    00210       operator++(int)
    00211       { return *this; }
    00212     };
    00213 } // namespace std
    00214 #endif