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         if (_M_sbuf)
 114           {
 115             _M_sbuf->sbumpc();
 116             _M_c = traits_type::eof();
 117           }
 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         istreambuf_iterator __old = *this;
 130         if (_M_sbuf)
 131           {
 132             __old._M_c = _M_sbuf->sbumpc();
 133             _M_c = traits_type::eof();
 134           }
 135         return __old;
 136       }
 137
 138       // _GLIBCXX_RESOLVE_LIB_DEFECTS
 139       // 110 istreambuf_iterator::equal not const
 140       // NB: there is also number 111 (NAD, Future) pending on this function.
 141       /// Return true both iterators are end or both are not end.
 142       bool
 143       equal(const istreambuf_iterator& __b) const
 144       {
 145         const bool __thiseof = _M_at_eof();
 146         const bool __beof = __b._M_at_eof();
 147         return (__thiseof && __beof || (!__thiseof && !__beof));
 148       }
 149
 150     private:
 151       int_type
 152       _M_get() const
 153       {
 154         const int_type __eof = traits_type::eof();
 155         int_type __ret = __eof;
 156         if (_M_sbuf)
 157           {
 158             if (!traits_type::eq_int_type(_M_c, __eof))
 159               __ret = _M_c;
 160             else if (!traits_type::eq_int_type((__ret = _M_sbuf->sgetc()),
 161                                                __eof))
 162               _M_c = __ret;
 163             else
 164               _M_sbuf = 0;
 165           }
 166         return __ret;
 167       }
 168
 169       bool
 170       _M_at_eof() const
 171       {
 172         const int_type __eof = traits_type::eof();
 173         return traits_type::eq_int_type(_M_get(), __eof);
 174       }
 175     };
 176
 177   template<typename _CharT, typename _Traits>
 178     inline bool
 179     operator==(const istreambuf_iterator<_CharT, _Traits>& __a,
 180                const istreambuf_iterator<_CharT, _Traits>& __b)
 181     { return __a.equal(__b); }
 182
 183   template<typename _CharT, typename _Traits>
 184     inline bool
 185     operator!=(const istreambuf_iterator<_CharT, _Traits>& __a,
 186                const istreambuf_iterator<_CharT, _Traits>& __b)
 187     { return !__a.equal(__b); }
 188
 189   /// Provides output iterator semantics for streambufs.
 190   template<typename _CharT, typename _Traits>
 191     class ostreambuf_iterator
 192     : public iterator<output_iterator_tag, void, void, void, void>
 193     {
 194     public:
 195       // Types:
 196       //@{
 197       /// Public typedefs
 198       typedef _CharT                           char_type;
 199       typedef _Traits                          traits_type;
 200       typedef basic_streambuf<_CharT, _Traits> streambuf_type;
 201       typedef basic_ostream<_CharT, _Traits>   ostream_type;
 202       //@}
 203
 204     private:
 205       streambuf_type*   _M_sbuf;
 206       bool              _M_failed;
 207
 208     public:
 209       ///  Construct output iterator from ostream.
 210       ostreambuf_iterator(ostream_type& __s) throw ()
 211       : _M_sbuf(__s.rdbuf()), _M_failed(!_M_sbuf) { }
 212
 213       ///  Construct output iterator from streambuf.
 214       ostreambuf_iterator(streambuf_type* __s) throw ()
 215       : _M_sbuf(__s), _M_failed(!_M_sbuf) { }
 216
 217       ///  Write character to streambuf.  Calls streambuf.sputc().
 218       ostreambuf_iterator&
 219       operator=(_CharT __c)
 220       {
 221         if (!_M_failed &&
 222             _Traits::eq_int_type(_M_sbuf->sputc(__c), _Traits::eof()))
 223           _M_failed = true;
 224         return *this;
 225       }
 226
 227       /// Return *this.
 228       ostreambuf_iterator&
 229       operator*()
 230       { return *this; }
 231
 232       /// Return *this.
 233       ostreambuf_iterator&
 234       operator++(int)
 235       { return *this; }
 236
 237       /// Return *this.
 238       ostreambuf_iterator&
 239       operator++()
 240       { return *this; }
 241
 242       /// Return true if previous operator=() failed.
 243       bool
 244       failed() const throw()
 245       { return _M_failed; }
 246
 247       ostreambuf_iterator&
 248       _M_put(const _CharT* __ws, streamsize __len)
 249       {
 250         if (__builtin_expect(!_M_failed, true)
 251             && __builtin_expect(this->_M_sbuf->sputn(__ws, __len) != __len,
 252                                 false))
 253           _M_failed = true;
 254         return *this;
 255       }
 256     };
 257 } // namespace std
 258 #endif