1 // Short-string-optimized versatile string base -*- C++ -*- 2 3 // Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010 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 3, 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 // Under Section 7 of GPL version 3, you are granted additional 18 // permissions described in the GCC Runtime Library Exception, version 19 // 3.1, as published by the Free Software Foundation. 20 21 // You should have received a copy of the GNU General Public License and 22 // a copy of the GCC Runtime Library Exception along with this program; 23 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 24 // <http://www.gnu.org/licenses/>. 25 26 /** @file ext/sso_string_base.h 27 * This is an internal header file, included by other library headers. 28 * Do not attempt to use it directly. @headername{ext/vstring.h} 29 */ 30 31 #ifndef _SSO_STRING_BASE_H 32 #define _SSO_STRING_BASE_H 1 33 34 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default) 35 { 36 _GLIBCXX_BEGIN_NAMESPACE_VERSION 37 38 template<typename _CharT, typename _Traits, typename _Alloc> 39 class __sso_string_base 40 : protected __vstring_utility<_CharT, _Traits, _Alloc> 41 { 42 public: 43 typedef _Traits traits_type; 44 typedef typename _Traits::char_type value_type; 45 46 typedef __vstring_utility<_CharT, _Traits, _Alloc> _Util_Base; 47 typedef typename _Util_Base::_CharT_alloc_type _CharT_alloc_type; 48 typedef typename _CharT_alloc_type::size_type size_type; 49 50 private: 51 // Data Members: 52 typename _Util_Base::template _Alloc_hider<_CharT_alloc_type> 53 _M_dataplus; 54 size_type _M_string_length; 55 56 enum { _S_local_capacity = 15 }; 57 58 union 59 { 60 _CharT _M_local_data[_S_local_capacity + 1]; 61 size_type _M_allocated_capacity; 62 }; 63 64 void 65 _M_data(_CharT* __p) 66 { _M_dataplus._M_p = __p; } 67 68 void 69 _M_length(size_type __length) 70 { _M_string_length = __length; } 71 72 void 73 _M_capacity(size_type __capacity) 74 { _M_allocated_capacity = __capacity; } 75 76 bool 77 _M_is_local() const 78 { return _M_data() == _M_local_data; } 79 80 // Create & Destroy 81 _CharT* 82 _M_create(size_type&, size_type); 83 84 void 85 _M_dispose() 86 { 87 if (!_M_is_local()) 88 _M_destroy(_M_allocated_capacity); 89 } 90 91 void 92 _M_destroy(size_type __size) throw() 93 { _M_get_allocator().deallocate(_M_data(), __size + 1); } 94 95 // _M_construct_aux is used to implement the 21.3.1 para 15 which 96 // requires special behaviour if _InIterator is an integral type 97 template<typename _InIterator> 98 void 99 _M_construct_aux(_InIterator __beg, _InIterator __end, 100 std::__false_type) 101 { 102 typedef typename iterator_traits<_InIterator>::iterator_category _Tag; 103 _M_construct(__beg, __end, _Tag()); 104 } 105 106 // _GLIBCXX_RESOLVE_LIB_DEFECTS 107 // 438. Ambiguity in the "do the right thing" clause 108 template<typename _Integer> 109 void 110 _M_construct_aux(_Integer __beg, _Integer __end, std::__true_type) 111 { _M_construct_aux_2(static_cast<size_type>(__beg), __end); } 112 113 void 114 _M_construct_aux_2(size_type __req, _CharT __c) 115 { _M_construct(__req, __c); } 116 117 template<typename _InIterator> 118 void 119 _M_construct(_InIterator __beg, _InIterator __end) 120 { 121 typedef typename std::__is_integer<_InIterator>::__type _Integral; 122 _M_construct_aux(__beg, __end, _Integral()); 123 } 124 125 // For Input Iterators, used in istreambuf_iterators, etc. 126 template<typename _InIterator> 127 void 128 _M_construct(_InIterator __beg, _InIterator __end, 129 std::input_iterator_tag); 130 131 // For forward_iterators up to random_access_iterators, used for 132 // string::iterator, _CharT*, etc. 133 template<typename _FwdIterator> 134 void 135 _M_construct(_FwdIterator __beg, _FwdIterator __end, 136 std::forward_iterator_tag); 137 138 void 139 _M_construct(size_type __req, _CharT __c); 140 141 public: 142 size_type 143 _M_max_size() const 144 { return (_M_get_allocator().max_size() - 1) / 2; } 145 146 _CharT* 147 _M_data() const 148 { return _M_dataplus._M_p; } 149 150 size_type 151 _M_length() const 152 { return _M_string_length; } 153 154 size_type 155 _M_capacity() const 156 { 157 return _M_is_local() ? size_type(_S_local_capacity) 158 : _M_allocated_capacity; 159 } 160 161 bool 162 _M_is_shared() const 163 { return false; } 164 165 void 166 _M_set_leaked() { } 167 168 void 169 _M_leak() { } 170 171 void 172 _M_set_length(size_type __n) 173 { 174 _M_length(__n); 175 traits_type::assign(_M_data()[__n], _CharT()); 176 } 177 178 __sso_string_base() 179 : _M_dataplus(_M_local_data) 180 { _M_set_length(0); } 181 182 __sso_string_base(const _Alloc& __a); 183 184 __sso_string_base(const __sso_string_base& __rcs); 185 186 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 187 __sso_string_base(__sso_string_base&& __rcs); 188 #endif 189 190 __sso_string_base(size_type __n, _CharT __c, const _Alloc& __a); 191 192 template<typename _InputIterator> 193 __sso_string_base(_InputIterator __beg, _InputIterator __end, 194 const _Alloc& __a); 195 196 ~__sso_string_base() 197 { _M_dispose(); } 198 199 _CharT_alloc_type& 200 _M_get_allocator() 201 { return _M_dataplus; } 202 203 const _CharT_alloc_type& 204 _M_get_allocator() const 205 { return _M_dataplus; } 206 207 void 208 _M_swap(__sso_string_base& __rcs); 209 210 void 211 _M_assign(const __sso_string_base& __rcs); 212 213 void 214 _M_reserve(size_type __res); 215 216 void 217 _M_mutate(size_type __pos, size_type __len1, const _CharT* __s, 218 size_type __len2); 219 220 void 221 _M_erase(size_type __pos, size_type __n); 222 223 void 224 _M_clear() 225 { _M_set_length(0); } 226 227 bool 228 _M_compare(const __sso_string_base&) const 229 { return false; } 230 }; 231 232 template<typename _CharT, typename _Traits, typename _Alloc> 233 void 234 __sso_string_base<_CharT, _Traits, _Alloc>:: 235 _M_swap(__sso_string_base& __rcs) 236 { 237 if (this == &__rcs) 238 return; 239 240 // _GLIBCXX_RESOLVE_LIB_DEFECTS 241 // 431. Swapping containers with unequal allocators. 242 std::__alloc_swap<_CharT_alloc_type>::_S_do_it(_M_get_allocator(), 243 __rcs._M_get_allocator()); 244 245 if (_M_is_local()) 246 if (__rcs._M_is_local()) 247 { 248 if (_M_length() && __rcs._M_length()) 249 { 250 _CharT __tmp_data[_S_local_capacity + 1]; 251 traits_type::copy(__tmp_data, __rcs._M_local_data, 252 _S_local_capacity + 1); 253 traits_type::copy(__rcs._M_local_data, _M_local_data, 254 _S_local_capacity + 1); 255 traits_type::copy(_M_local_data, __tmp_data, 256 _S_local_capacity + 1); 257 } 258 else if (__rcs._M_length()) 259 { 260 traits_type::copy(_M_local_data, __rcs._M_local_data, 261 _S_local_capacity + 1); 262 _M_length(__rcs._M_length()); 263 __rcs._M_set_length(0); 264 return; 265 } 266 else if (_M_length()) 267 { 268 traits_type::copy(__rcs._M_local_data, _M_local_data, 269 _S_local_capacity + 1); 270 __rcs._M_length(_M_length()); 271 _M_set_length(0); 272 return; 273 } 274 } 275 else 276 { 277 const size_type __tmp_capacity = __rcs._M_allocated_capacity; 278 traits_type::copy(__rcs._M_local_data, _M_local_data, 279 _S_local_capacity + 1); 280 _M_data(__rcs._M_data()); 281 __rcs._M_data(__rcs._M_local_data); 282 _M_capacity(__tmp_capacity); 283 } 284 else 285 { 286 const size_type __tmp_capacity = _M_allocated_capacity; 287 if (__rcs._M_is_local()) 288 { 289 traits_type::copy(_M_local_data, __rcs._M_local_data, 290 _S_local_capacity + 1); 291 __rcs._M_data(_M_data()); 292 _M_data(_M_local_data); 293 } 294 else 295 { 296 _CharT* __tmp_ptr = _M_data(); 297 _M_data(__rcs._M_data()); 298 __rcs._M_data(__tmp_ptr); 299 _M_capacity(__rcs._M_allocated_capacity); 300 } 301 __rcs._M_capacity(__tmp_capacity); 302 } 303 304 const size_type __tmp_length = _M_length(); 305 _M_length(__rcs._M_length()); 306 __rcs._M_length(__tmp_length); 307 } 308 309 template<typename _CharT, typename _Traits, typename _Alloc> 310 _CharT* 311 __sso_string_base<_CharT, _Traits, _Alloc>:: 312 _M_create(size_type& __capacity, size_type __old_capacity) 313 { 314 // _GLIBCXX_RESOLVE_LIB_DEFECTS 315 // 83. String::npos vs. string::max_size() 316 if (__capacity > _M_max_size()) 317 std::__throw_length_error(__N("__sso_string_base::_M_create")); 318 319 // The below implements an exponential growth policy, necessary to 320 // meet amortized linear time requirements of the library: see 321 // http://gcc.gnu.org/ml/libstdc++/2001-07/msg00085.html. 322 if (__capacity > __old_capacity && __capacity < 2 * __old_capacity) 323 { 324 __capacity = 2 * __old_capacity; 325 // Never allocate a string bigger than max_size. 326 if (__capacity > _M_max_size()) 327 __capacity = _M_max_size(); 328 } 329 330 // NB: Need an array of char_type[__capacity], plus a terminating 331 // null char_type() element. 332 return _M_get_allocator().allocate(__capacity + 1); 333 } 334 335 template<typename _CharT, typename _Traits, typename _Alloc> 336 __sso_string_base<_CharT, _Traits, _Alloc>:: 337 __sso_string_base(const _Alloc& __a) 338 : _M_dataplus(__a, _M_local_data) 339 { _M_set_length(0); } 340 341 template<typename _CharT, typename _Traits, typename _Alloc> 342 __sso_string_base<_CharT, _Traits, _Alloc>:: 343 __sso_string_base(const __sso_string_base& __rcs) 344 : _M_dataplus(__rcs._M_get_allocator(), _M_local_data) 345 { _M_construct(__rcs._M_data(), __rcs._M_data() + __rcs._M_length()); } 346 347 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 348 template<typename _CharT, typename _Traits, typename _Alloc> 349 __sso_string_base<_CharT, _Traits, _Alloc>:: 350 __sso_string_base(__sso_string_base&& __rcs) 351 : _M_dataplus(__rcs._M_get_allocator(), _M_local_data) 352 { 353 if (__rcs._M_is_local()) 354 { 355 if (__rcs._M_length()) 356 traits_type::copy(_M_local_data, __rcs._M_local_data, 357 _S_local_capacity + 1); 358 } 359 else 360 { 361 _M_data(__rcs._M_data()); 362 _M_capacity(__rcs._M_allocated_capacity); 363 } 364 365 _M_length(__rcs._M_length()); 366 __rcs._M_length(0); 367 __rcs._M_data(__rcs._M_local_data); 368 } 369 #endif 370 371 template<typename _CharT, typename _Traits, typename _Alloc> 372 __sso_string_base<_CharT, _Traits, _Alloc>:: 373 __sso_string_base(size_type __n, _CharT __c, const _Alloc& __a) 374 : _M_dataplus(__a, _M_local_data) 375 { _M_construct(__n, __c); } 376 377 template<typename _CharT, typename _Traits, typename _Alloc> 378 template<typename _InputIterator> 379 __sso_string_base<_CharT, _Traits, _Alloc>:: 380 __sso_string_base(_InputIterator __beg, _InputIterator __end, 381 const _Alloc& __a) 382 : _M_dataplus(__a, _M_local_data) 383 { _M_construct(__beg, __end); } 384 385 // NB: This is the special case for Input Iterators, used in 386 // istreambuf_iterators, etc. 387 // Input Iterators have a cost structure very different from 388 // pointers, calling for a different coding style. 389 template<typename _CharT, typename _Traits, typename _Alloc> 390 template<typename _InIterator> 391 void 392 __sso_string_base<_CharT, _Traits, _Alloc>:: 393 _M_construct(_InIterator __beg, _InIterator __end, 394 std::input_iterator_tag) 395 { 396 size_type __len = 0; 397 size_type __capacity = size_type(_S_local_capacity); 398 399 while (__beg != __end && __len < __capacity) 400 { 401 _M_data()[__len++] = *__beg; 402 ++__beg; 403 } 404 405 __try 406 { 407 while (__beg != __end) 408 { 409 if (__len == __capacity) 410 { 411 // Allocate more space. 412 __capacity = __len + 1; 413 _CharT* __another = _M_create(__capacity, __len); 414 this->_S_copy(__another, _M_data(), __len); 415 _M_dispose(); 416 _M_data(__another); 417 _M_capacity(__capacity); 418 } 419 _M_data()[__len++] = *__beg; 420 ++__beg; 421 } 422 } 423 __catch(...) 424 { 425 _M_dispose(); 426 __throw_exception_again; 427 } 428 429 _M_set_length(__len); 430 } 431 432 template<typename _CharT, typename _Traits, typename _Alloc> 433 template<typename _InIterator> 434 void 435 __sso_string_base<_CharT, _Traits, _Alloc>:: 436 _M_construct(_InIterator __beg, _InIterator __end, 437 std::forward_iterator_tag) 438 { 439 // NB: Not required, but considered best practice. 440 if (__is_null_pointer(__beg) && __beg != __end) 441 std::__throw_logic_error(__N("__sso_string_base::" 442 "_M_construct null not valid")); 443 444 size_type __dnew = static_cast<size_type>(std::distance(__beg, __end)); 445 446 if (__dnew > size_type(_S_local_capacity)) 447 { 448 _M_data(_M_create(__dnew, size_type(0))); 449 _M_capacity(__dnew); 450 } 451 452 // Check for out_of_range and length_error exceptions. 453 __try 454 { this->_S_copy_chars(_M_data(), __beg, __end); } 455 __catch(...) 456 { 457 _M_dispose(); 458 __throw_exception_again; 459 } 460 461 _M_set_length(__dnew); 462 } 463 464 template<typename _CharT, typename _Traits, typename _Alloc> 465 void 466 __sso_string_base<_CharT, _Traits, _Alloc>:: 467 _M_construct(size_type __n, _CharT __c) 468 { 469 if (__n > size_type(_S_local_capacity)) 470 { 471 _M_data(_M_create(__n, size_type(0))); 472 _M_capacity(__n); 473 } 474 475 if (__n) 476 this->_S_assign(_M_data(), __n, __c); 477 478 _M_set_length(__n); 479 } 480 481 template<typename _CharT, typename _Traits, typename _Alloc> 482 void 483 __sso_string_base<_CharT, _Traits, _Alloc>:: 484 _M_assign(const __sso_string_base& __rcs) 485 { 486 if (this != &__rcs) 487 { 488 const size_type __rsize = __rcs._M_length(); 489 const size_type __capacity = _M_capacity(); 490 491 if (__rsize > __capacity) 492 { 493 size_type __new_capacity = __rsize; 494 _CharT* __tmp = _M_create(__new_capacity, __capacity); 495 _M_dispose(); 496 _M_data(__tmp); 497 _M_capacity(__new_capacity); 498 } 499 500 if (__rsize) 501 this->_S_copy(_M_data(), __rcs._M_data(), __rsize); 502 503 _M_set_length(__rsize); 504 } 505 } 506 507 template<typename _CharT, typename _Traits, typename _Alloc> 508 void 509 __sso_string_base<_CharT, _Traits, _Alloc>:: 510 _M_reserve(size_type __res) 511 { 512 // Make sure we don't shrink below the current size. 513 if (__res < _M_length()) 514 __res = _M_length(); 515 516 const size_type __capacity = _M_capacity(); 517 if (__res != __capacity) 518 { 519 if (__res > __capacity 520 || __res > size_type(_S_local_capacity)) 521 { 522 _CharT* __tmp = _M_create(__res, __capacity); 523 this->_S_copy(__tmp, _M_data(), _M_length() + 1); 524 _M_dispose(); 525 _M_data(__tmp); 526 _M_capacity(__res); 527 } 528 else if (!_M_is_local()) 529 { 530 this->_S_copy(_M_local_data, _M_data(), _M_length() + 1); 531 _M_destroy(__capacity); 532 _M_data(_M_local_data); 533 } 534 } 535 } 536 537 template<typename _CharT, typename _Traits, typename _Alloc> 538 void 539 __sso_string_base<_CharT, _Traits, _Alloc>:: 540 _M_mutate(size_type __pos, size_type __len1, const _CharT* __s, 541 size_type __len2) 542 { 543 const size_type __how_much = _M_length() - __pos - __len1; 544 545 size_type __new_capacity = _M_length() + __len2 - __len1; 546 _CharT* __r = _M_create(__new_capacity, _M_capacity()); 547 548 if (__pos) 549 this->_S_copy(__r, _M_data(), __pos); 550 if (__s && __len2) 551 this->_S_copy(__r + __pos, __s, __len2); 552 if (__how_much) 553 this->_S_copy(__r + __pos + __len2, 554 _M_data() + __pos + __len1, __how_much); 555 556 _M_dispose(); 557 _M_data(__r); 558 _M_capacity(__new_capacity); 559 } 560 561 template<typename _CharT, typename _Traits, typename _Alloc> 562 void 563 __sso_string_base<_CharT, _Traits, _Alloc>:: 564 _M_erase(size_type __pos, size_type __n) 565 { 566 const size_type __how_much = _M_length() - __pos - __n; 567 568 if (__how_much && __n) 569 this->_S_move(_M_data() + __pos, _M_data() + __pos + __n, __how_much); 570 571 _M_set_length(_M_length() - __n); 572 } 573 574 _GLIBCXX_END_NAMESPACE_VERSION 575 } // namespace 576 577 #endif /* _SSO_STRING_BASE_H */ 578