libstdc++-v3/include/bits/streambuf_iterator.h

   1 // Streambuf iterators
   2
   3 // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004
   4 // Free Software Foundation, Inc.
   5 //
   6 // This file is part of the GNU ISO C++ Library.  This library is free
   7 // software; you can redistribute it and/or modify it under the
   8 // terms of the GNU General Public License as published by the
   9 // Free Software Foundation; either version 2, or (at your option)
  10 // any later version.
  11
  12 // This library is distributed in the hope that it will be useful,
  13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 // GNU General Public License for more details.
  16
  17 // You should have received a copy of the GNU General Public License along
  18 // with this library; see the file COPYING.  If not, write to the Free
  19 // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
  20 // USA.
  21
  22 // As a special exception, you may use this file as part of a free software
  23 // library without restriction.  Specifically, if other files instantiate
  24 // templates or use macros or inline functions from this file, or you compile
  25 // this file and link it with other files to produce an executable, this
  26 // file does not by itself cause the resulting executable to be covered by
  27 // the GNU General Public License.  This exception does not however
  28 // invalidate any other reasons why the executable file might be covered by
  29 // the GNU General Public License.
  30
  31 /** @file streambuf_iterator.h
  32  *  This is an internal header file, included by other library headers.
  33  *  You should not attempt to use it directly.
  34  */
  35
  36 #ifndef _STREAMBUF_ITERATOR_H
  37 #define _STREAMBUF_ITERATOR_H 1
  38
  39 #pragma GCC system_header
  40
  41 #include <streambuf>
  42 #include <debug/debug.h>
  43
  44 // NB: Should specialize copy, find algorithms for streambuf iterators.
  45
  46 namespace std
  47 {
  48   // 24.5.3 Template class istreambuf_iterator
  49   /// Provides input iterator semantics for streambufs.
  50   template<typename _CharT, typename _Traits>
  51     class istreambuf_iterator
  52     : public iterator<input_iterator_tag, _CharT, typename _Traits::off_type,
  53                       _CharT*, _CharT&>
  54     {
  55     public:
  56       // Types:
  57       //@{
  58       /// Public typedefs
  59       typedef _CharT                                    char_type;
  60       typedef _Traits                                   traits_type;
  61       typedef typename _Traits::int_type                int_type;
  62       typedef basic_streambuf<_CharT, _Traits>          streambuf_type;
  63       typedef basic_istream<_CharT, _Traits>            istream_type;
  64       //@}
  65
  66     private:
  67       // 24.5.3 istreambuf_iterator
  68       // p 1
  69       // If the end of stream is reached (streambuf_type::sgetc()
  70       // returns traits_type::eof()), the iterator becomes equal to
  71       // the "end of stream" iterator value.
  72       // NB: This implementation assumes the "end of stream" value
  73       // is EOF, or -1.
  74       mutable streambuf_type*   _M_sbuf;
  75       mutable int_type          _M_c;
  76
  77     public:
  78       ///  Construct end of input stream iterator.
  79       istreambuf_iterator() throw()
  80       : _M_sbuf(0), _M_c(traits_type::eof()) { }
  81
  82       ///  Construct start of input stream iterator.
  83       istreambuf_iterator(istream_type& __s) throw()
  84       : _M_sbuf(__s.rdbuf()), _M_c(traits_type::eof()) { }
  85
  86       ///  Construct start of streambuf iterator.
  87       istreambuf_iterator(streambuf_type* __s) throw()
  88       : _M_sbuf(__s), _M_c(traits_type::eof()) { }
  89
  90       ///  Return the current character pointed to by iterator.  This returns
  91       ///  streambuf.sgetc().  It cannot be assigned.  NB: The result of
  92       ///  operator*() on an end of stream is undefined.
  93       char_type
  94       operator*() const
  95       {
  96 #ifdef _GLIBCXX_DEBUG_PEDANTIC
  97         // Dereferencing a past-the-end istreambuf_iterator is a
  98         // libstdc++ extension
  99         __glibcxx_requires_cond(!_M_at_eof(),
 100                                 _M_message(__gnu_debug::__msg_deref_istreambuf)
 101                                 ._M_iterator(*this));
 102 #endif
 103         return traits_type::to_char_type(_M_get());
 104       }
 105
 106       /// Advance the iterator.  Calls streambuf.sbumpc().
 107       istreambuf_iterator&
 108       operator++()
 109       {
 110         __glibcxx_requires_cond(!_M_at_eof(),
 111                                 _M_message(__gnu_debug::__msg_inc_istreambuf)
 112                                 ._M_iterator(*this));
 113         const int_type __eof = traits_type::eof();
 114         if (_M_sbuf && traits_type::eq_int_type(_M_sbuf->sbumpc(), __eof))
 115           _M_sbuf = 0;
 116         else
 117           _M_c = __eof;
 118         return *this;
 119       }
 120
 121       /// Advance the iterator.  Calls streambuf.sbumpc().
 122       istreambuf_iterator
 123       operator++(int)
 124       {
 125         __glibcxx_requires_cond(!_M_at_eof(),
 126                                 _M_message(__gnu_debug::__msg_inc_istreambuf)
 127                                 ._M_iterator(*this));
 128
 129         const int_type __eof = traits_type::eof();
 130         istreambuf_iterator __old = *this;
 131         if (_M_sbuf
 132             && traits_type::eq_int_type((__old._M_c = _M_sbuf->sbumpc()),
 133                                         __eof))
 134           _M_sbuf = 0;
 135         else
 136           _M_c = __eof;
 137         return __old;
 138       }
 139
 140       // _GLIBCXX_RESOLVE_LIB_DEFECTS
 141       // 110 istreambuf_iterator::equal not const
 142       // NB: there is also number 111 (NAD, Future) pending on this function.
 143       /// Return true both iterators are end or both are not end.
 144       bool
 145       equal(const istreambuf_iterator& __b) const
 146       {
 147         const bool __thiseof = _M_at_eof();
 148         const bool __beof = __b._M_at_eof();
 149         return (__thiseof && __beof || (!__thiseof && !__beof));
 150       }
 151
 152     private:
 153       int_type
 154       _M_get() const
 155       {
 156         const int_type __eof = traits_type::eof();
 157         int_type __ret = __eof;
 158         if (_M_sbuf)
 159           {
 160             if (!traits_type::eq_int_type(_M_c, __eof)
 161                 || !traits_type::eq_int_type((_M_c = _M_sbuf->sgetc()),
 162                                              __eof))
 163               __ret = _M_c;
 164             else
 165               _M_sbuf = 0;
 166           }
 167         return __ret;
 168       }
 169
 170       bool
 171       _M_at_eof() const
 172       {
 173         const int_type __eof = traits_type::eof();
 174         return traits_type::eq_int_type(_M_get(), __eof);
 175       }
 176     };
 177
 178   template<typename _CharT, typename _Traits>
 179     inline bool
 180     operator==(const istreambuf_iterator<_CharT, _Traits>& __a,
 181                const istreambuf_iterator<_CharT, _Traits>& __b)
 182     { return __a.equal(__b); }
 183
 184   template<typename _CharT, typename _Traits>
 185     inline bool
 186     operator!=(const istreambuf_iterator<_CharT, _Traits>& __a,
 187                const istreambuf_iterator<_CharT, _Traits>& __b)
 188     { return !__a.equal(__b); }
 189
 190   /// Provides output iterator semantics for streambufs.
 191   template<typename _CharT, typename _Traits>
 192     class ostreambuf_iterator
 193     : public iterator<output_iterator_tag, void, void, void, void>
 194     {
 195     public:
 196       // Types:
 197       //@{
 198       /// Public typedefs
 199       typedef _CharT                           char_type;
 200       typedef _Traits                          traits_type;
 201       typedef basic_streambuf<_CharT, _Traits> streambuf_type;
 202       typedef basic_ostream<_CharT, _Traits>   ostream_type;
 203       //@}
 204
 205     private:
 206       streambuf_type*   _M_sbuf;
 207       bool              _M_failed;
 208
 209     public:
 210       ///  Construct output iterator from ostream.
 211       ostreambuf_iterator(ostream_type& __s) throw ()
 212       : _M_sbuf(__s.rdbuf()), _M_failed(!_M_sbuf) { }
 213
 214       ///  Construct output iterator from streambuf.
 215       ostreambuf_iterator(streambuf_type* __s) throw ()
 216       : _M_sbuf(__s), _M_failed(!_M_sbuf) { }
 217
 218       ///  Write character to streambuf.  Calls streambuf.sputc().
 219       ostreambuf_iterator&
 220       operator=(_CharT __c)
 221       {
 222         if (!_M_failed &&
 223             _Traits::eq_int_type(_M_sbuf->sputc(__c), _Traits::eof()))
 224           _M_failed = true;
 225         return *this;
 226       }
 227
 228       /// Return *this.
 229       ostreambuf_iterator&
 230       operator*()
 231       { return *this; }
 232
 233       /// Return *this.
 234       ostreambuf_iterator&
 235       operator++(int)
 236       { return *this; }
 237
 238       /// Return *this.
 239       ostreambuf_iterator&
 240       operator++()
 241       { return *this; }
 242
 243       /// Return true if previous operator=() failed.
 244       bool
 245       failed() const throw()
 246       { return _M_failed; }
 247
 248       ostreambuf_iterator&
 249       _M_put(const _CharT* __ws, streamsize __len)
 250       {
 251         if (__builtin_expect(!_M_failed, true)
 252             && __builtin_expect(this->_M_sbuf->sputn(__ws, __len) != __len,
 253                                 false))
 254           _M_failed = true;
 255         return *this;
 256       }
 257     };
 258 } // namespace std
 259 #endif