1 // Streambuf iterators 2 3 // Copyright (C) 1997-2019 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 3, 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 // Under Section 7 of GPL version 3, you are granted additional 17 // permissions described in the GCC Runtime Library Exception, version 18 // 3.1, as published by the Free Software Foundation. 19 20 // You should have received a copy of the GNU General Public License and 21 // a copy of the GCC Runtime Library Exception along with this program; 22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 23 // <http://www.gnu.org/licenses/>. 24 25 /** @file bits/streambuf_iterator.h 26 * This is an internal header file, included by other library headers. 27 * Do not attempt to use it directly. @headername{iterator} 28 */ 29 30 #ifndef _STREAMBUF_ITERATOR_H 31 #define _STREAMBUF_ITERATOR_H 1 32 33 #pragma GCC system_header 34 35 #include <streambuf> 36 #include <debug/debug.h> 37 38 namespace std _GLIBCXX_VISIBILITY(default) 39 { 40 _GLIBCXX_BEGIN_NAMESPACE_VERSION 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*, 53 #if __cplusplus >= 201103L 54 // LWG 445. 55 _CharT> 56 #else 57 _CharT&> 58 #endif 59 { 60 public: 61 // Types: 62 //@{ 63 /// Public typedefs 64 typedef _CharT char_type; 65 typedef _Traits traits_type; 66 typedef typename _Traits::int_type int_type; 67 typedef basic_streambuf<_CharT, _Traits> streambuf_type; 68 typedef basic_istream<_CharT, _Traits> istream_type; 69 //@} 70 71 template<typename _CharT2> 72 friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value, 73 ostreambuf_iterator<_CharT2> >::__type 74 copy(istreambuf_iterator<_CharT2>, istreambuf_iterator<_CharT2>, 75 ostreambuf_iterator<_CharT2>); 76 77 template<bool _IsMove, typename _CharT2> 78 friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value, 79 _CharT2*>::__type 80 __copy_move_a2(istreambuf_iterator<_CharT2>, 81 istreambuf_iterator<_CharT2>, _CharT2*); 82 83 template<typename _CharT2> 84 friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value, 85 istreambuf_iterator<_CharT2> >::__type 86 find(istreambuf_iterator<_CharT2>, istreambuf_iterator<_CharT2>, 87 const _CharT2&); 88 89 template<typename _CharT2, typename _Distance> 90 friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value, 91 void>::__type 92 advance(istreambuf_iterator<_CharT2>&, _Distance); 93 94 private: 95 // 24.5.3 istreambuf_iterator 96 // p 1 97 // If the end of stream is reached (streambuf_type::sgetc() 98 // returns traits_type::eof()), the iterator becomes equal to 99 // the "end of stream" iterator value. 100 // NB: This implementation assumes the "end of stream" value 101 // is EOF, or -1. 102 mutable streambuf_type* _M_sbuf; 103 int_type _M_c; 104 105 public: 106 /// Construct end of input stream iterator. 107 _GLIBCXX_CONSTEXPR istreambuf_iterator() _GLIBCXX_USE_NOEXCEPT 108 : _M_sbuf(0), _M_c(traits_type::eof()) { } 109 110 #if __cplusplus >= 201103L 111 istreambuf_iterator(const istreambuf_iterator&) noexcept = default; 112 113 ~istreambuf_iterator() = default; 114 #endif 115 116 /// Construct start of input stream iterator. 117 istreambuf_iterator(istream_type& __s) _GLIBCXX_USE_NOEXCEPT 118 : _M_sbuf(__s.rdbuf()), _M_c(traits_type::eof()) { } 119 120 /// Construct start of streambuf iterator. 121 istreambuf_iterator(streambuf_type* __s) _GLIBCXX_USE_NOEXCEPT 122 : _M_sbuf(__s), _M_c(traits_type::eof()) { } 123 124 #if __cplusplus >= 201103L 125 istreambuf_iterator& 126 operator=(const istreambuf_iterator&) noexcept = default; 127 #endif 128 129 /// Return the current character pointed to by iterator. This returns 130 /// streambuf.sgetc(). It cannot be assigned. NB: The result of 131 /// operator*() on an end of stream is undefined. 132 char_type 133 operator*() const 134 { 135 int_type __c = _M_get(); 136 137 #ifdef _GLIBCXX_DEBUG_PEDANTIC 138 // Dereferencing a past-the-end istreambuf_iterator is a 139 // libstdc++ extension 140 __glibcxx_requires_cond(!_S_is_eof(__c), 141 _M_message(__gnu_debug::__msg_deref_istreambuf) 142 ._M_iterator(*this)); 143 #endif 144 return traits_type::to_char_type(__c); 145 } 146 147 /// Advance the iterator. Calls streambuf.sbumpc(). 148 istreambuf_iterator& 149 operator++() 150 { 151 __glibcxx_requires_cond(_M_sbuf && 152 (!_S_is_eof(_M_c) || !_S_is_eof(_M_sbuf->sgetc())), 153 _M_message(__gnu_debug::__msg_inc_istreambuf) 154 ._M_iterator(*this)); 155 156 _M_sbuf->sbumpc(); 157 _M_c = traits_type::eof(); 158 return *this; 159 } 160 161 /// Advance the iterator. Calls streambuf.sbumpc(). 162 istreambuf_iterator 163 operator++(int) 164 { 165 __glibcxx_requires_cond(_M_sbuf && 166 (!_S_is_eof(_M_c) || !_S_is_eof(_M_sbuf->sgetc())), 167 _M_message(__gnu_debug::__msg_inc_istreambuf) 168 ._M_iterator(*this)); 169 170 istreambuf_iterator __old = *this; 171 __old._M_c = _M_sbuf->sbumpc(); 172 _M_c = traits_type::eof(); 173 return __old; 174 } 175 176 // _GLIBCXX_RESOLVE_LIB_DEFECTS 177 // 110 istreambuf_iterator::equal not const 178 // NB: there is also number 111 (NAD) relevant to this function. 179 /// Return true both iterators are end or both are not end. 180 bool 181 equal(const istreambuf_iterator& __b) const 182 { return _M_at_eof() == __b._M_at_eof(); } 183 184 private: 185 int_type 186 _M_get() const 187 { 188 int_type __ret = _M_c; 189 if (_M_sbuf && _S_is_eof(__ret) && _S_is_eof(__ret = _M_sbuf->sgetc())) 190 _M_sbuf = 0; 191 return __ret; 192 } 193 194 bool 195 _M_at_eof() const 196 { return _S_is_eof(_M_get()); } 197 198 static bool 199 _S_is_eof(int_type __c) 200 { 201 const int_type __eof = traits_type::eof(); 202 return traits_type::eq_int_type(__c, __eof); 203 } 204 }; 205 206 template<typename _CharT, typename _Traits> 207 inline bool 208 operator==(const istreambuf_iterator<_CharT, _Traits>& __a, 209 const istreambuf_iterator<_CharT, _Traits>& __b) 210 { return __a.equal(__b); } 211 212 template<typename _CharT, typename _Traits> 213 inline bool 214 operator!=(const istreambuf_iterator<_CharT, _Traits>& __a, 215 const istreambuf_iterator<_CharT, _Traits>& __b) 216 { return !__a.equal(__b); } 217 218 /// Provides output iterator semantics for streambufs. 219 template<typename _CharT, typename _Traits> 220 class ostreambuf_iterator 221 : public iterator<output_iterator_tag, void, void, void, void> 222 { 223 public: 224 // Types: 225 //@{ 226 /// Public typedefs 227 typedef _CharT char_type; 228 typedef _Traits traits_type; 229 typedef basic_streambuf<_CharT, _Traits> streambuf_type; 230 typedef basic_ostream<_CharT, _Traits> ostream_type; 231 //@} 232 233 template<typename _CharT2> 234 friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value, 235 ostreambuf_iterator<_CharT2> >::__type 236 copy(istreambuf_iterator<_CharT2>, istreambuf_iterator<_CharT2>, 237 ostreambuf_iterator<_CharT2>); 238 239 private: 240 streambuf_type* _M_sbuf; 241 bool _M_failed; 242 243 public: 244 /// Construct output iterator from ostream. 245 ostreambuf_iterator(ostream_type& __s) _GLIBCXX_USE_NOEXCEPT 246 : _M_sbuf(__s.rdbuf()), _M_failed(!_M_sbuf) { } 247 248 /// Construct output iterator from streambuf. 249 ostreambuf_iterator(streambuf_type* __s) _GLIBCXX_USE_NOEXCEPT 250 : _M_sbuf(__s), _M_failed(!_M_sbuf) { } 251 252 /// Write character to streambuf. Calls streambuf.sputc(). 253 ostreambuf_iterator& 254 operator=(_CharT __c) 255 { 256 if (!_M_failed && 257 _Traits::eq_int_type(_M_sbuf->sputc(__c), _Traits::eof())) 258 _M_failed = true; 259 return *this; 260 } 261 262 /// Return *this. 263 ostreambuf_iterator& 264 operator*() 265 { return *this; } 266 267 /// Return *this. 268 ostreambuf_iterator& 269 operator++(int) 270 { return *this; } 271 272 /// Return *this. 273 ostreambuf_iterator& 274 operator++() 275 { return *this; } 276 277 /// Return true if previous operator=() failed. 278 bool 279 failed() const _GLIBCXX_USE_NOEXCEPT 280 { return _M_failed; } 281 282 ostreambuf_iterator& 283 _M_put(const _CharT* __ws, streamsize __len) 284 { 285 if (__builtin_expect(!_M_failed, true) 286 && __builtin_expect(this->_M_sbuf->sputn(__ws, __len) != __len, 287 false)) 288 _M_failed = true; 289 return *this; 290 } 291 }; 292 293 // Overloads for streambuf iterators. 294 template<typename _CharT> 295 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value, 296 ostreambuf_iterator<_CharT> >::__type 297 copy(istreambuf_iterator<_CharT> __first, 298 istreambuf_iterator<_CharT> __last, 299 ostreambuf_iterator<_CharT> __result) 300 { 301 if (__first._M_sbuf && !__last._M_sbuf && !__result._M_failed) 302 { 303 bool __ineof; 304 __copy_streambufs_eof(__first._M_sbuf, __result._M_sbuf, __ineof); 305 if (!__ineof) 306 __result._M_failed = true; 307 } 308 return __result; 309 } 310 311 template<bool _IsMove, typename _CharT> 312 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value, 313 ostreambuf_iterator<_CharT> >::__type 314 __copy_move_a2(_CharT* __first, _CharT* __last, 315 ostreambuf_iterator<_CharT> __result) 316 { 317 const streamsize __num = __last - __first; 318 if (__num > 0) 319 __result._M_put(__first, __num); 320 return __result; 321 } 322 323 template<bool _IsMove, typename _CharT> 324 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value, 325 ostreambuf_iterator<_CharT> >::__type 326 __copy_move_a2(const _CharT* __first, const _CharT* __last, 327 ostreambuf_iterator<_CharT> __result) 328 { 329 const streamsize __num = __last - __first; 330 if (__num > 0) 331 __result._M_put(__first, __num); 332 return __result; 333 } 334 335 template<bool _IsMove, typename _CharT> 336 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value, 337 _CharT*>::__type 338 __copy_move_a2(istreambuf_iterator<_CharT> __first, 339 istreambuf_iterator<_CharT> __last, _CharT* __result) 340 { 341 typedef istreambuf_iterator<_CharT> __is_iterator_type; 342 typedef typename __is_iterator_type::traits_type traits_type; 343 typedef typename __is_iterator_type::streambuf_type streambuf_type; 344 typedef typename traits_type::int_type int_type; 345 346 if (__first._M_sbuf && !__last._M_sbuf) 347 { 348 streambuf_type* __sb = __first._M_sbuf; 349 int_type __c = __sb->sgetc(); 350 while (!traits_type::eq_int_type(__c, traits_type::eof())) 351 { 352 const streamsize __n = __sb->egptr() - __sb->gptr(); 353 if (__n > 1) 354 { 355 traits_type::copy(__result, __sb->gptr(), __n); 356 __sb->__safe_gbump(__n); 357 __result += __n; 358 __c = __sb->underflow(); 359 } 360 else 361 { 362 *__result++ = traits_type::to_char_type(__c); 363 __c = __sb->snextc(); 364 } 365 } 366 } 367 return __result; 368 } 369 370 template<typename _CharT> 371 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value, 372 istreambuf_iterator<_CharT> >::__type 373 find(istreambuf_iterator<_CharT> __first, 374 istreambuf_iterator<_CharT> __last, const _CharT& __val) 375 { 376 typedef istreambuf_iterator<_CharT> __is_iterator_type; 377 typedef typename __is_iterator_type::traits_type traits_type; 378 typedef typename __is_iterator_type::streambuf_type streambuf_type; 379 typedef typename traits_type::int_type int_type; 380 const int_type __eof = traits_type::eof(); 381 382 if (__first._M_sbuf && !__last._M_sbuf) 383 { 384 const int_type __ival = traits_type::to_int_type(__val); 385 streambuf_type* __sb = __first._M_sbuf; 386 int_type __c = __sb->sgetc(); 387 while (!traits_type::eq_int_type(__c, __eof) 388 && !traits_type::eq_int_type(__c, __ival)) 389 { 390 streamsize __n = __sb->egptr() - __sb->gptr(); 391 if (__n > 1) 392 { 393 const _CharT* __p = traits_type::find(__sb->gptr(), 394 __n, __val); 395 if (__p) 396 __n = __p - __sb->gptr(); 397 __sb->__safe_gbump(__n); 398 __c = __sb->sgetc(); 399 } 400 else 401 __c = __sb->snextc(); 402 } 403 404 __first._M_c = __eof; 405 } 406 407 return __first; 408 } 409 410 template<typename _CharT, typename _Distance> 411 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value, 412 void>::__type 413 advance(istreambuf_iterator<_CharT>& __i, _Distance __n) 414 { 415 if (__n == 0) 416 return; 417 418 __glibcxx_assert(__n > 0); 419 __glibcxx_requires_cond(!__i._M_at_eof(), 420 _M_message(__gnu_debug::__msg_inc_istreambuf) 421 ._M_iterator(__i)); 422 423 typedef istreambuf_iterator<_CharT> __is_iterator_type; 424 typedef typename __is_iterator_type::traits_type traits_type; 425 typedef typename __is_iterator_type::streambuf_type streambuf_type; 426 typedef typename traits_type::int_type int_type; 427 const int_type __eof = traits_type::eof(); 428 429 streambuf_type* __sb = __i._M_sbuf; 430 while (__n > 0) 431 { 432 streamsize __size = __sb->egptr() - __sb->gptr(); 433 if (__size > __n) 434 { 435 __sb->__safe_gbump(__n); 436 break; 437 } 438 439 __sb->__safe_gbump(__size); 440 __n -= __size; 441 if (traits_type::eq_int_type(__sb->underflow(), __eof)) 442 { 443 __glibcxx_requires_cond(__n == 0, 444 _M_message(__gnu_debug::__msg_inc_istreambuf) 445 ._M_iterator(__i)); 446 break; 447 } 448 } 449 450 __i._M_c = __eof; 451 } 452 453 // @} group iterators 454 455 _GLIBCXX_END_NAMESPACE_VERSION 456 } // namespace 457 458 #endif 459