1 // Streambuf iterators 2 3 // Copyright (C) 1997-2020 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*, _CharT> 53 { 54 public: 55 // Types: 56 ///@{ 57 /// Public typedefs 58 #if __cplusplus < 201103L 59 typedef _CharT& reference; // Changed to _CharT by LWG 445 60 #elif __cplusplus > 201703L 61 // _GLIBCXX_RESOLVE_LIB_DEFECTS 62 // 3188. istreambuf_iterator::pointer should not be unspecified 63 using pointer = void; 64 #endif 65 66 typedef _CharT char_type; 67 typedef _Traits traits_type; 68 typedef typename _Traits::int_type int_type; 69 typedef basic_streambuf<_CharT, _Traits> streambuf_type; 70 typedef basic_istream<_CharT, _Traits> istream_type; 71 ///@} 72 73 template<typename _CharT2> 74 friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value, 75 ostreambuf_iterator<_CharT2> >::__type 76 copy(istreambuf_iterator<_CharT2>, istreambuf_iterator<_CharT2>, 77 ostreambuf_iterator<_CharT2>); 78 79 template<bool _IsMove, typename _CharT2> 80 friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value, 81 _CharT2*>::__type 82 __copy_move_a2(istreambuf_iterator<_CharT2>, 83 istreambuf_iterator<_CharT2>, _CharT2*); 84 85 #if __cplusplus >= 201103L 86 template<typename _CharT2, typename _Size> 87 friend __enable_if_t<__is_char<_CharT2>::__value, _CharT2*> 88 __copy_n_a(istreambuf_iterator<_CharT2>, _Size, _CharT2*); 89 #endif 90 91 template<typename _CharT2> 92 friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value, 93 istreambuf_iterator<_CharT2> >::__type 94 find(istreambuf_iterator<_CharT2>, istreambuf_iterator<_CharT2>, 95 const _CharT2&); 96 97 template<typename _CharT2, typename _Distance> 98 friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value, 99 void>::__type 100 advance(istreambuf_iterator<_CharT2>&, _Distance); 101 102 private: 103 // 24.5.3 istreambuf_iterator 104 // p 1 105 // If the end of stream is reached (streambuf_type::sgetc() 106 // returns traits_type::eof()), the iterator becomes equal to 107 // the "end of stream" iterator value. 108 // NB: This implementation assumes the "end of stream" value 109 // is EOF, or -1. 110 mutable streambuf_type* _M_sbuf; 111 int_type _M_c; 112 113 public: 114 /// Construct end of input stream iterator. 115 _GLIBCXX_CONSTEXPR istreambuf_iterator() _GLIBCXX_USE_NOEXCEPT 116 : _M_sbuf(0), _M_c(traits_type::eof()) { } 117 118 #if __cplusplus > 201703L && __cpp_lib_concepts 119 constexpr istreambuf_iterator(default_sentinel_t) noexcept 120 : istreambuf_iterator() { } 121 #endif 122 123 #if __cplusplus >= 201103L 124 istreambuf_iterator(const istreambuf_iterator&) noexcept = default; 125 126 ~istreambuf_iterator() = default; 127 #endif 128 129 /// Construct start of input stream iterator. 130 istreambuf_iterator(istream_type& __s) _GLIBCXX_USE_NOEXCEPT 131 : _M_sbuf(__s.rdbuf()), _M_c(traits_type::eof()) { } 132 133 /// Construct start of streambuf iterator. 134 istreambuf_iterator(streambuf_type* __s) _GLIBCXX_USE_NOEXCEPT 135 : _M_sbuf(__s), _M_c(traits_type::eof()) { } 136 137 #if __cplusplus >= 201103L 138 istreambuf_iterator& 139 operator=(const istreambuf_iterator&) noexcept = default; 140 #endif 141 142 /// Return the current character pointed to by iterator. This returns 143 /// streambuf.sgetc(). It cannot be assigned. NB: The result of 144 /// operator*() on an end of stream is undefined. 145 char_type 146 operator*() const 147 { 148 int_type __c = _M_get(); 149 150 #ifdef _GLIBCXX_DEBUG_PEDANTIC 151 // Dereferencing a past-the-end istreambuf_iterator is a 152 // libstdc++ extension 153 __glibcxx_requires_cond(!_S_is_eof(__c), 154 _M_message(__gnu_debug::__msg_deref_istreambuf) 155 ._M_iterator(*this)); 156 #endif 157 return traits_type::to_char_type(__c); 158 } 159 160 /// Advance the iterator. Calls streambuf.sbumpc(). 161 istreambuf_iterator& 162 operator++() 163 { 164 __glibcxx_requires_cond(_M_sbuf && 165 (!_S_is_eof(_M_c) || !_S_is_eof(_M_sbuf->sgetc())), 166 _M_message(__gnu_debug::__msg_inc_istreambuf) 167 ._M_iterator(*this)); 168 169 _M_sbuf->sbumpc(); 170 _M_c = traits_type::eof(); 171 return *this; 172 } 173 174 /// Advance the iterator. Calls streambuf.sbumpc(). 175 istreambuf_iterator 176 operator++(int) 177 { 178 __glibcxx_requires_cond(_M_sbuf && 179 (!_S_is_eof(_M_c) || !_S_is_eof(_M_sbuf->sgetc())), 180 _M_message(__gnu_debug::__msg_inc_istreambuf) 181 ._M_iterator(*this)); 182 183 istreambuf_iterator __old = *this; 184 __old._M_c = _M_sbuf->sbumpc(); 185 _M_c = traits_type::eof(); 186 return __old; 187 } 188 189 // _GLIBCXX_RESOLVE_LIB_DEFECTS 190 // 110 istreambuf_iterator::equal not const 191 // NB: there is also number 111 (NAD) relevant to this function. 192 /// Return true both iterators are end or both are not end. 193 bool 194 equal(const istreambuf_iterator& __b) const 195 { return _M_at_eof() == __b._M_at_eof(); } 196 197 private: 198 int_type 199 _M_get() const 200 { 201 int_type __ret = _M_c; 202 if (_M_sbuf && _S_is_eof(__ret) && _S_is_eof(__ret = _M_sbuf->sgetc())) 203 _M_sbuf = 0; 204 return __ret; 205 } 206 207 bool 208 _M_at_eof() const 209 { return _S_is_eof(_M_get()); } 210 211 static bool 212 _S_is_eof(int_type __c) 213 { 214 const int_type __eof = traits_type::eof(); 215 return traits_type::eq_int_type(__c, __eof); 216 } 217 218 #if __cplusplus > 201703L && __cpp_lib_concepts 219 friend bool 220 operator==(const istreambuf_iterator& __i, default_sentinel_t __s) 221 { return __i._M_at_eof(); } 222 #endif 223 }; 224 225 template<typename _CharT, typename _Traits> 226 inline bool 227 operator==(const istreambuf_iterator<_CharT, _Traits>& __a, 228 const istreambuf_iterator<_CharT, _Traits>& __b) 229 { return __a.equal(__b); } 230 231 template<typename _CharT, typename _Traits> 232 inline bool 233 operator!=(const istreambuf_iterator<_CharT, _Traits>& __a, 234 const istreambuf_iterator<_CharT, _Traits>& __b) 235 { return !__a.equal(__b); } 236 237 /// Provides output iterator semantics for streambufs. 238 template<typename _CharT, typename _Traits> 239 class ostreambuf_iterator 240 : public iterator<output_iterator_tag, void, void, void, void> 241 { 242 public: 243 // Types: 244 ///@{ 245 /// Public typedefs 246 #if __cplusplus > 201703L 247 using difference_type = ptrdiff_t; 248 #endif 249 typedef _CharT char_type; 250 typedef _Traits traits_type; 251 typedef basic_streambuf<_CharT, _Traits> streambuf_type; 252 typedef basic_ostream<_CharT, _Traits> ostream_type; 253 ///@} 254 255 template<typename _CharT2> 256 friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value, 257 ostreambuf_iterator<_CharT2> >::__type 258 copy(istreambuf_iterator<_CharT2>, istreambuf_iterator<_CharT2>, 259 ostreambuf_iterator<_CharT2>); 260 261 private: 262 streambuf_type* _M_sbuf; 263 bool _M_failed; 264 265 public: 266 267 #if __cplusplus > 201703L 268 constexpr 269 ostreambuf_iterator() noexcept 270 : _M_sbuf(nullptr), _M_failed(true) { } 271 #endif 272 273 /// Construct output iterator from ostream. 274 ostreambuf_iterator(ostream_type& __s) _GLIBCXX_USE_NOEXCEPT 275 : _M_sbuf(__s.rdbuf()), _M_failed(!_M_sbuf) { } 276 277 /// Construct output iterator from streambuf. 278 ostreambuf_iterator(streambuf_type* __s) _GLIBCXX_USE_NOEXCEPT 279 : _M_sbuf(__s), _M_failed(!_M_sbuf) { } 280 281 /// Write character to streambuf. Calls streambuf.sputc(). 282 ostreambuf_iterator& 283 operator=(_CharT __c) 284 { 285 if (!_M_failed && 286 _Traits::eq_int_type(_M_sbuf->sputc(__c), _Traits::eof())) 287 _M_failed = true; 288 return *this; 289 } 290 291 /// Return *this. 292 ostreambuf_iterator& 293 operator*() 294 { return *this; } 295 296 /// Return *this. 297 ostreambuf_iterator& 298 operator++(int) 299 { return *this; } 300 301 /// Return *this. 302 ostreambuf_iterator& 303 operator++() 304 { return *this; } 305 306 /// Return true if previous operator=() failed. 307 bool 308 failed() const _GLIBCXX_USE_NOEXCEPT 309 { return _M_failed; } 310 311 ostreambuf_iterator& 312 _M_put(const _CharT* __ws, streamsize __len) 313 { 314 if (__builtin_expect(!_M_failed, true) 315 && __builtin_expect(this->_M_sbuf->sputn(__ws, __len) != __len, 316 false)) 317 _M_failed = true; 318 return *this; 319 } 320 }; 321 322 // Overloads for streambuf iterators. 323 template<typename _CharT> 324 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value, 325 ostreambuf_iterator<_CharT> >::__type 326 copy(istreambuf_iterator<_CharT> __first, 327 istreambuf_iterator<_CharT> __last, 328 ostreambuf_iterator<_CharT> __result) 329 { 330 if (__first._M_sbuf && !__last._M_sbuf && !__result._M_failed) 331 { 332 bool __ineof; 333 __copy_streambufs_eof(__first._M_sbuf, __result._M_sbuf, __ineof); 334 if (!__ineof) 335 __result._M_failed = true; 336 } 337 return __result; 338 } 339 340 template<bool _IsMove, typename _CharT> 341 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value, 342 ostreambuf_iterator<_CharT> >::__type 343 __copy_move_a2(_CharT* __first, _CharT* __last, 344 ostreambuf_iterator<_CharT> __result) 345 { 346 const streamsize __num = __last - __first; 347 if (__num > 0) 348 __result._M_put(__first, __num); 349 return __result; 350 } 351 352 template<bool _IsMove, typename _CharT> 353 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value, 354 ostreambuf_iterator<_CharT> >::__type 355 __copy_move_a2(const _CharT* __first, const _CharT* __last, 356 ostreambuf_iterator<_CharT> __result) 357 { 358 const streamsize __num = __last - __first; 359 if (__num > 0) 360 __result._M_put(__first, __num); 361 return __result; 362 } 363 364 template<bool _IsMove, typename _CharT> 365 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value, 366 _CharT*>::__type 367 __copy_move_a2(istreambuf_iterator<_CharT> __first, 368 istreambuf_iterator<_CharT> __last, _CharT* __result) 369 { 370 typedef istreambuf_iterator<_CharT> __is_iterator_type; 371 typedef typename __is_iterator_type::traits_type traits_type; 372 typedef typename __is_iterator_type::streambuf_type streambuf_type; 373 typedef typename traits_type::int_type int_type; 374 375 if (__first._M_sbuf && !__last._M_sbuf) 376 { 377 streambuf_type* __sb = __first._M_sbuf; 378 int_type __c = __sb->sgetc(); 379 while (!traits_type::eq_int_type(__c, traits_type::eof())) 380 { 381 const streamsize __n = __sb->egptr() - __sb->gptr(); 382 if (__n > 1) 383 { 384 traits_type::copy(__result, __sb->gptr(), __n); 385 __sb->__safe_gbump(__n); 386 __result += __n; 387 __c = __sb->underflow(); 388 } 389 else 390 { 391 *__result++ = traits_type::to_char_type(__c); 392 __c = __sb->snextc(); 393 } 394 } 395 } 396 return __result; 397 } 398 399 #if __cplusplus >= 201103L 400 template<typename _CharT, typename _Size> 401 __enable_if_t<__is_char<_CharT>::__value, _CharT*> 402 __copy_n_a(istreambuf_iterator<_CharT> __it, _Size __n, _CharT* __result) 403 { 404 if (__n == 0) 405 return __result; 406 407 __glibcxx_requires_cond(__it._M_sbuf, 408 _M_message(__gnu_debug::__msg_inc_istreambuf) 409 ._M_iterator(__it)); 410 _CharT* __beg = __result; 411 __result += __it._M_sbuf->sgetn(__beg, __n); 412 __glibcxx_requires_cond(__result - __beg == __n, 413 _M_message(__gnu_debug::__msg_inc_istreambuf) 414 ._M_iterator(__it)); 415 return __result; 416 } 417 #endif // C++11 418 419 template<typename _CharT> 420 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value, 421 istreambuf_iterator<_CharT> >::__type 422 find(istreambuf_iterator<_CharT> __first, 423 istreambuf_iterator<_CharT> __last, const _CharT& __val) 424 { 425 typedef istreambuf_iterator<_CharT> __is_iterator_type; 426 typedef typename __is_iterator_type::traits_type traits_type; 427 typedef typename __is_iterator_type::streambuf_type streambuf_type; 428 typedef typename traits_type::int_type int_type; 429 const int_type __eof = traits_type::eof(); 430 431 if (__first._M_sbuf && !__last._M_sbuf) 432 { 433 const int_type __ival = traits_type::to_int_type(__val); 434 streambuf_type* __sb = __first._M_sbuf; 435 int_type __c = __sb->sgetc(); 436 while (!traits_type::eq_int_type(__c, __eof) 437 && !traits_type::eq_int_type(__c, __ival)) 438 { 439 streamsize __n = __sb->egptr() - __sb->gptr(); 440 if (__n > 1) 441 { 442 const _CharT* __p = traits_type::find(__sb->gptr(), 443 __n, __val); 444 if (__p) 445 __n = __p - __sb->gptr(); 446 __sb->__safe_gbump(__n); 447 __c = __sb->sgetc(); 448 } 449 else 450 __c = __sb->snextc(); 451 } 452 453 __first._M_c = __eof; 454 } 455 456 return __first; 457 } 458 459 template<typename _CharT, typename _Distance> 460 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value, 461 void>::__type 462 advance(istreambuf_iterator<_CharT>& __i, _Distance __n) 463 { 464 if (__n == 0) 465 return; 466 467 __glibcxx_assert(__n > 0); 468 __glibcxx_requires_cond(!__i._M_at_eof(), 469 _M_message(__gnu_debug::__msg_inc_istreambuf) 470 ._M_iterator(__i)); 471 472 typedef istreambuf_iterator<_CharT> __is_iterator_type; 473 typedef typename __is_iterator_type::traits_type traits_type; 474 typedef typename __is_iterator_type::streambuf_type streambuf_type; 475 typedef typename traits_type::int_type int_type; 476 const int_type __eof = traits_type::eof(); 477 478 streambuf_type* __sb = __i._M_sbuf; 479 while (__n > 0) 480 { 481 streamsize __size = __sb->egptr() - __sb->gptr(); 482 if (__size > __n) 483 { 484 __sb->__safe_gbump(__n); 485 break; 486 } 487 488 __sb->__safe_gbump(__size); 489 __n -= __size; 490 if (traits_type::eq_int_type(__sb->underflow(), __eof)) 491 { 492 __glibcxx_requires_cond(__n == 0, 493 _M_message(__gnu_debug::__msg_inc_istreambuf) 494 ._M_iterator(__i)); 495 break; 496 } 497 } 498 499 __i._M_c = __eof; 500 } 501 502 /// @} group iterators 503 504 _GLIBCXX_END_NAMESPACE_VERSION 505 } // namespace 506 507 #endif 508