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

   1 // Streambuf iterators
   2
   3 // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
   4 // 2006, 2007, 2009, 2010
   5 // Free Software Foundation, Inc.
   6 //
   7 // This file is part of the GNU ISO C++ Library.  This library is free
   8 // software; you can redistribute it and/or modify it under the
   9 // terms of the GNU General Public License as published by the
  10 // Free Software Foundation; either version 3, or (at your option)
  11 // any later version.
  12
  13 // This library is distributed in the hope that it will be useful,
  14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 // GNU General Public License for more details.
  17
  18 // Under Section 7 of GPL version 3, you are granted additional
  19 // permissions described in the GCC Runtime Library Exception, version
  20 // 3.1, as published by the Free Software Foundation.
  21
  22 // You should have received a copy of the GNU General Public License and
  23 // a copy of the GCC Runtime Library Exception along with this program;
  24 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  25 // <http://www.gnu.org/licenses/>.
  26
  27 /** @file bits/streambuf_iterator.h
  28  *  This is an internal header file, included by other library headers.
  29  *  Do not attempt to use it directly. @headername{iterator}
  30  */
  31
  32 #ifndef _STREAMBUF_ITERATOR_H
  33 #define _STREAMBUF_ITERATOR_H 1
  34
  35 #pragma GCC system_header
  36
  37 #include <streambuf>
  38 #include <debug/debug.h>
  39
  40 _GLIBCXX_BEGIN_NAMESPACE(std)
  41
  42   /**
  43    * @addtogroup iterators
  44    * @{
  45    */
  46
  47   // 24.5.3 Template class istreambuf_iterator
  48   /// Provides input iterator semantics for streambufs.
  49   template<typename _CharT, typename _Traits>
  50     class istreambuf_iterator
  51     : public iterator<input_iterator_tag, _CharT, typename _Traits::off_type,
  52                       _CharT*, _CharT&>
  53     {
  54     public:
  55       // Types:
  56       //@{
  57       /// Public typedefs
  58       typedef _CharT                                    char_type;
  59       typedef _Traits                                   traits_type;
  60       typedef typename _Traits::int_type                int_type;
  61       typedef basic_streambuf<_CharT, _Traits>          streambuf_type;
  62       typedef basic_istream<_CharT, _Traits>            istream_type;
  63       //@}
  64
  65       template<typename _CharT2>
  66         friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value,
  67                                     ostreambuf_iterator<_CharT2> >::__type
  68         copy(istreambuf_iterator<_CharT2>, istreambuf_iterator<_CharT2>,
  69              ostreambuf_iterator<_CharT2>);
  70
  71       template<bool _IsMove, typename _CharT2>
  72         friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value,
  73                                                _CharT2*>::__type
  74         __copy_move_a2(istreambuf_iterator<_CharT2>,
  75                        istreambuf_iterator<_CharT2>, _CharT2*);
  76
  77       template<typename _CharT2>
  78         friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value,
  79                                     istreambuf_iterator<_CharT2> >::__type
  80         find(istreambuf_iterator<_CharT2>, istreambuf_iterator<_CharT2>,
  81              const _CharT2&);
  82
  83     private:
  84       // 24.5.3 istreambuf_iterator
  85       // p 1
  86       // If the end of stream is reached (streambuf_type::sgetc()
  87       // returns traits_type::eof()), the iterator becomes equal to
  88       // the "end of stream" iterator value.
  89       // NB: This implementation assumes the "end of stream" value
  90       // is EOF, or -1.
  91       mutable streambuf_type*   _M_sbuf;
  92       mutable int_type          _M_c;
  93
  94     public:
  95       ///  Construct end of input stream iterator.
  96       _GLIBCXX_CONSTEXPR istreambuf_iterator() throw()
  97       : _M_sbuf(0), _M_c(traits_type::eof()) { }
  98
  99       ///  Construct start of input stream iterator.
 100       istreambuf_iterator(istream_type& __s) throw()
 101       : _M_sbuf(__s.rdbuf()), _M_c(traits_type::eof()) { }
 102
 103       ///  Construct start of streambuf iterator.
 104       istreambuf_iterator(streambuf_type* __s) throw()
 105       : _M_sbuf(__s), _M_c(traits_type::eof()) { }
 106
 107       ///  Return the current character pointed to by iterator.  This returns
 108       ///  streambuf.sgetc().  It cannot be assigned.  NB: The result of
 109       ///  operator*() on an end of stream is undefined.
 110       char_type
 111       operator*() const
 112       {
 113 #ifdef _GLIBCXX_DEBUG_PEDANTIC
 114         // Dereferencing a past-the-end istreambuf_iterator is a
 115         // libstdc++ extension
 116         __glibcxx_requires_cond(!_M_at_eof(),
 117                                 _M_message(__gnu_debug::__msg_deref_istreambuf)
 118                                 ._M_iterator(*this));
 119 #endif
 120         return traits_type::to_char_type(_M_get());
 121       }
 122
 123       /// Advance the iterator.  Calls streambuf.sbumpc().
 124       istreambuf_iterator&
 125       operator++()
 126       {
 127         __glibcxx_requires_cond(!_M_at_eof(),
 128                                 _M_message(__gnu_debug::__msg_inc_istreambuf)
 129                                 ._M_iterator(*this));
 130         if (_M_sbuf)
 131           {
 132             _M_sbuf->sbumpc();
 133             _M_c = traits_type::eof();
 134           }
 135         return *this;
 136       }
 137
 138       /// Advance the iterator.  Calls streambuf.sbumpc().
 139       istreambuf_iterator
 140       operator++(int)
 141       {
 142         __glibcxx_requires_cond(!_M_at_eof(),
 143                                 _M_message(__gnu_debug::__msg_inc_istreambuf)
 144                                 ._M_iterator(*this));
 145
 146         istreambuf_iterator __old = *this;
 147         if (_M_sbuf)
 148           {
 149             __old._M_c = _M_sbuf->sbumpc();
 150             _M_c = traits_type::eof();
 151           }
 152         return __old;
 153       }
 154
 155       // _GLIBCXX_RESOLVE_LIB_DEFECTS
 156       // 110 istreambuf_iterator::equal not const
 157       // NB: there is also number 111 (NAD, Future) pending on this function.
 158       /// Return true both iterators are end or both are not end.
 159       bool
 160       equal(const istreambuf_iterator& __b) const
 161       { return _M_at_eof() == __b._M_at_eof(); }
 162
 163     private:
 164       int_type
 165       _M_get() const
 166       {
 167         const int_type __eof = traits_type::eof();
 168         int_type __ret = __eof;
 169         if (_M_sbuf)
 170           {
 171             if (!traits_type::eq_int_type(_M_c, __eof))
 172               __ret = _M_c;
 173             else if (!traits_type::eq_int_type((__ret = _M_sbuf->sgetc()),
 174                                                __eof))
 175               _M_c = __ret;
 176             else
 177               _M_sbuf = 0;
 178           }
 179         return __ret;
 180       }
 181
 182       bool
 183       _M_at_eof() const
 184       {
 185         const int_type __eof = traits_type::eof();
 186         return traits_type::eq_int_type(_M_get(), __eof);
 187       }
 188     };
 189
 190   template<typename _CharT, typename _Traits>
 191     inline bool
 192     operator==(const istreambuf_iterator<_CharT, _Traits>& __a,
 193                const istreambuf_iterator<_CharT, _Traits>& __b)
 194     { return __a.equal(__b); }
 195
 196   template<typename _CharT, typename _Traits>
 197     inline bool
 198     operator!=(const istreambuf_iterator<_CharT, _Traits>& __a,
 199                const istreambuf_iterator<_CharT, _Traits>& __b)
 200     { return !__a.equal(__b); }
 201
 202   /// Provides output iterator semantics for streambufs.
 203   template<typename _CharT, typename _Traits>
 204     class ostreambuf_iterator
 205     : public iterator<output_iterator_tag, void, void, void, void>
 206     {
 207     public:
 208       // Types:
 209       //@{
 210       /// Public typedefs
 211       typedef _CharT                           char_type;
 212       typedef _Traits                          traits_type;
 213       typedef basic_streambuf<_CharT, _Traits> streambuf_type;
 214       typedef basic_ostream<_CharT, _Traits>   ostream_type;
 215       //@}
 216
 217       template<typename _CharT2>
 218         friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value,
 219                                     ostreambuf_iterator<_CharT2> >::__type
 220         copy(istreambuf_iterator<_CharT2>, istreambuf_iterator<_CharT2>,
 221              ostreambuf_iterator<_CharT2>);
 222
 223     private:
 224       streambuf_type*   _M_sbuf;
 225       bool              _M_failed;
 226
 227     public:
 228       ///  Construct output iterator from ostream.
 229       ostreambuf_iterator(ostream_type& __s) throw ()
 230       : _M_sbuf(__s.rdbuf()), _M_failed(!_M_sbuf) { }
 231
 232       ///  Construct output iterator from streambuf.
 233       ostreambuf_iterator(streambuf_type* __s) throw ()
 234       : _M_sbuf(__s), _M_failed(!_M_sbuf) { }
 235
 236       ///  Write character to streambuf.  Calls streambuf.sputc().
 237       ostreambuf_iterator&
 238       operator=(_CharT __c)
 239       {
 240         if (!_M_failed &&
 241             _Traits::eq_int_type(_M_sbuf->sputc(__c), _Traits::eof()))
 242           _M_failed = true;
 243         return *this;
 244       }
 245
 246       /// Return *this.
 247       ostreambuf_iterator&
 248       operator*()
 249       { return *this; }
 250
 251       /// Return *this.
 252       ostreambuf_iterator&
 253       operator++(int)
 254       { return *this; }
 255
 256       /// Return *this.
 257       ostreambuf_iterator&
 258       operator++()
 259       { return *this; }
 260
 261       /// Return true if previous operator=() failed.
 262       bool
 263       failed() const throw()
 264       { return _M_failed; }
 265
 266       ostreambuf_iterator&
 267       _M_put(const _CharT* __ws, streamsize __len)
 268       {
 269         if (__builtin_expect(!_M_failed, true)
 270             && __builtin_expect(this->_M_sbuf->sputn(__ws, __len) != __len,
 271                                 false))
 272           _M_failed = true;
 273         return *this;
 274       }
 275     };
 276
 277   // Overloads for streambuf iterators.
 278   template<typename _CharT>
 279     typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
 280                                     ostreambuf_iterator<_CharT> >::__type
 281     copy(istreambuf_iterator<_CharT> __first,
 282          istreambuf_iterator<_CharT> __last,
 283          ostreambuf_iterator<_CharT> __result)
 284     {
 285       if (__first._M_sbuf && !__last._M_sbuf && !__result._M_failed)
 286         {
 287           bool __ineof;
 288           __copy_streambufs_eof(__first._M_sbuf, __result._M_sbuf, __ineof);
 289           if (!__ineof)
 290             __result._M_failed = true;
 291         }
 292       return __result;
 293     }
 294
 295   template<bool _IsMove, typename _CharT>
 296     typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
 297                                     ostreambuf_iterator<_CharT> >::__type
 298     __copy_move_a2(_CharT* __first, _CharT* __last,
 299                    ostreambuf_iterator<_CharT> __result)
 300     {
 301       const streamsize __num = __last - __first;
 302       if (__num > 0)
 303         __result._M_put(__first, __num);
 304       return __result;
 305     }
 306
 307   template<bool _IsMove, typename _CharT>
 308     typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
 309                                     ostreambuf_iterator<_CharT> >::__type
 310     __copy_move_a2(const _CharT* __first, const _CharT* __last,
 311                    ostreambuf_iterator<_CharT> __result)
 312     {
 313       const streamsize __num = __last - __first;
 314       if (__num > 0)
 315         __result._M_put(__first, __num);
 316       return __result;
 317     }
 318
 319   template<bool _IsMove, typename _CharT>
 320     typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
 321                                     _CharT*>::__type
 322     __copy_move_a2(istreambuf_iterator<_CharT> __first,
 323                    istreambuf_iterator<_CharT> __last, _CharT* __result)
 324     {
 325       typedef istreambuf_iterator<_CharT>                  __is_iterator_type;
 326       typedef typename __is_iterator_type::traits_type     traits_type;
 327       typedef typename __is_iterator_type::streambuf_type  streambuf_type;
 328       typedef typename traits_type::int_type               int_type;
 329
 330       if (__first._M_sbuf && !__last._M_sbuf)
 331         {
 332           streambuf_type* __sb = __first._M_sbuf;
 333           int_type __c = __sb->sgetc();
 334           while (!traits_type::eq_int_type(__c, traits_type::eof()))
 335             {
 336               const streamsize __n = __sb->egptr() - __sb->gptr();
 337               if (__n > 1)
 338                 {
 339                   traits_type::copy(__result, __sb->gptr(), __n);
 340                   __sb->gbump(__n);
 341                   __result += __n;
 342                   __c = __sb->underflow();
 343                 }
 344               else
 345                 {
 346                   *__result++ = traits_type::to_char_type(__c);
 347                   __c = __sb->snextc();
 348                 }
 349             }
 350         }
 351       return __result;
 352     }
 353
 354   template<typename _CharT>
 355     typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
 356                                     istreambuf_iterator<_CharT> >::__type
 357     find(istreambuf_iterator<_CharT> __first,
 358          istreambuf_iterator<_CharT> __last, const _CharT& __val)
 359     {
 360       typedef istreambuf_iterator<_CharT>                  __is_iterator_type;
 361       typedef typename __is_iterator_type::traits_type     traits_type;
 362       typedef typename __is_iterator_type::streambuf_type  streambuf_type;
 363       typedef typename traits_type::int_type               int_type;
 364
 365       if (__first._M_sbuf && !__last._M_sbuf)
 366         {
 367           const int_type __ival = traits_type::to_int_type(__val);
 368           streambuf_type* __sb = __first._M_sbuf;
 369           int_type __c = __sb->sgetc();
 370           while (!traits_type::eq_int_type(__c, traits_type::eof())
 371                  && !traits_type::eq_int_type(__c, __ival))
 372             {
 373               streamsize __n = __sb->egptr() - __sb->gptr();
 374               if (__n > 1)
 375                 {
 376                   const _CharT* __p = traits_type::find(__sb->gptr(),
 377                                                         __n, __val);
 378                   if (__p)
 379                     __n = __p - __sb->gptr();
 380                   __sb->gbump(__n);
 381                   __c = __sb->sgetc();
 382                 }
 383               else
 384                 __c = __sb->snextc();
 385             }
 386
 387           if (!traits_type::eq_int_type(__c, traits_type::eof()))
 388             __first._M_c = __c;
 389           else
 390             __first._M_sbuf = 0;
 391         }
 392       return __first;
 393     }
 394
 395 // @} group iterators
 396
 397 _GLIBCXX_END_NAMESPACE
 398
 399 #endif