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 #if __google_stl_debug_string_dangling 90 else { 91 // Wipe local storage for destructed string with 0xCD. 92 // This mimics what DebugAllocation does to free()d memory. 93 __builtin_memset(_M_local_data, 0xcd, sizeof(_M_local_data)); 94 } 95 #endif 96 } 97 98 void 99 _M_destroy(size_type __size) throw() 100 { _M_get_allocator().deallocate(_M_data(), __size + 1); } 101 102 // _M_construct_aux is used to implement the 21.3.1 para 15 which 103 // requires special behaviour if _InIterator is an integral type 104 template<typename _InIterator> 105 void 106 _M_construct_aux(_InIterator __beg, _InIterator __end, 107 std::__false_type) 108 { 109 typedef typename iterator_traits<_InIterator>::iterator_category _Tag; 110 _M_construct(__beg, __end, _Tag()); 111 } 112 113 // _GLIBCXX_RESOLVE_LIB_DEFECTS 114 // 438. Ambiguity in the "do the right thing" clause 115 template<typename _Integer> 116 void 117 _M_construct_aux(_Integer __beg, _Integer __end, std::__true_type) 118 { _M_construct_aux_2(static_cast<size_type>(__beg), __end); } 119 120 void 121 _M_construct_aux_2(size_type __req, _CharT __c) 122 { _M_construct(__req, __c); } 123 124 template<typename _InIterator> 125 void 126 _M_construct(_InIterator __beg, _InIterator __end) 127 { 128 typedef typename std::__is_integer<_InIterator>::__type _Integral; 129 _M_construct_aux(__beg, __end, _Integral()); 130 } 131 132 // For Input Iterators, used in istreambuf_iterators, etc. 133 template<typename _InIterator> 134 void 135 _M_construct(_InIterator __beg, _InIterator __end, 136 std::input_iterator_tag); 137 138 // For forward_iterators up to random_access_iterators, used for 139 // string::iterator, _CharT*, etc. 140 template<typename _FwdIterator> 141 void 142 _M_construct(_FwdIterator __beg, _FwdIterator __end, 143 std::forward_iterator_tag); 144 145 void 146 _M_construct(size_type __req, _CharT __c); 147 148 public: 149 size_type 150 _M_max_size() const 151 { return (_M_get_allocator().max_size() - 1) / 2; } 152 153 _CharT* 154 _M_data() const 155 { return _M_dataplus._M_p; } 156 157 size_type 158 _M_length() const 159 { return _M_string_length; } 160 161 size_type 162 _M_capacity() const 163 { 164 return _M_is_local() ? size_type(_S_local_capacity) 165 : _M_allocated_capacity; 166 } 167 168 bool 169 _M_is_shared() const 170 { return false; } 171 172 void 173 _M_set_leaked() { } 174 175 void 176 _M_leak() { } 177 178 void 179 _M_set_length_no_wipe(size_type __n) 180 { 181 _M_length(__n); 182 traits_type::assign(_M_data()[__n], _CharT()); 183 } 184 185 void 186 _M_set_length(size_type __n) 187 { 188 #if __google_stl_debug_string_dangling 189 if (__n + 1 < _M_length()) 190 { 191 // Wipe the storage with 0xCD. 192 // Also wipes the old NUL terminator. 193 __builtin_memset(_M_data() + __n + 1, 0xcd, _M_length() - __n); 194 } 195 #endif 196 _M_set_length_no_wipe(__n); 197 } 198 199 __sso_string_base() 200 : _M_dataplus(_M_local_data) 201 { _M_set_length_no_wipe(0); } 202 203 __sso_string_base(const _Alloc& __a); 204 205 __sso_string_base(const __sso_string_base& __rcs); 206 207 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 208 __sso_string_base(__sso_string_base&& __rcs); 209 #endif 210 211 __sso_string_base(size_type __n, _CharT __c, const _Alloc& __a); 212 213 template<typename _InputIterator> 214 __sso_string_base(_InputIterator __beg, _InputIterator __end, 215 const _Alloc& __a); 216 217 ~__sso_string_base() 218 { _M_dispose(); } 219 220 _CharT_alloc_type& 221 _M_get_allocator() 222 { return _M_dataplus; } 223 224 const _CharT_alloc_type& 225 _M_get_allocator() const 226 { return _M_dataplus; } 227 228 void 229 _M_swap(__sso_string_base& __rcs); 230 231 void 232 _M_assign(const __sso_string_base& __rcs); 233 234 void 235 _M_reserve(size_type __res); 236 237 void 238 _M_mutate(size_type __pos, size_type __len1, const _CharT* __s, 239 size_type __len2); 240 241 void 242 _M_erase(size_type __pos, size_type __n); 243 244 void 245 _M_clear() 246 { _M_set_length(0); } 247 248 bool 249 _M_compare(const __sso_string_base&) const 250 { return false; } 251 }; 252 253 template<typename _CharT, typename _Traits, typename _Alloc> 254 void 255 __sso_string_base<_CharT, _Traits, _Alloc>:: 256 _M_swap(__sso_string_base& __rcs) 257 { 258 if (this == &__rcs) 259 return; 260 261 // _GLIBCXX_RESOLVE_LIB_DEFECTS 262 // 431. Swapping containers with unequal allocators. 263 std::__alloc_swap<_CharT_alloc_type>::_S_do_it(_M_get_allocator(), 264 __rcs._M_get_allocator()); 265 266 if (_M_is_local()) 267 if (__rcs._M_is_local()) 268 { 269 if (_M_length() && __rcs._M_length()) 270 { 271 _CharT __tmp_data[_S_local_capacity + 1]; 272 traits_type::copy(__tmp_data, __rcs._M_local_data, 273 _S_local_capacity + 1); 274 traits_type::copy(__rcs._M_local_data, _M_local_data, 275 _S_local_capacity + 1); 276 traits_type::copy(_M_local_data, __tmp_data, 277 _S_local_capacity + 1); 278 } 279 else if (__rcs._M_length()) 280 { 281 traits_type::copy(_M_local_data, __rcs._M_local_data, 282 _S_local_capacity + 1); 283 _M_length(__rcs._M_length()); 284 __rcs._M_set_length(0); 285 return; 286 } 287 else if (_M_length()) 288 { 289 traits_type::copy(__rcs._M_local_data, _M_local_data, 290 _S_local_capacity + 1); 291 __rcs._M_length(_M_length()); 292 _M_set_length(0); 293 return; 294 } 295 } 296 else 297 { 298 const size_type __tmp_capacity = __rcs._M_allocated_capacity; 299 traits_type::copy(__rcs._M_local_data, _M_local_data, 300 _S_local_capacity + 1); 301 _M_data(__rcs._M_data()); 302 __rcs._M_data(__rcs._M_local_data); 303 _M_capacity(__tmp_capacity); 304 } 305 else 306 { 307 const size_type __tmp_capacity = _M_allocated_capacity; 308 if (__rcs._M_is_local()) 309 { 310 traits_type::copy(_M_local_data, __rcs._M_local_data, 311 _S_local_capacity + 1); 312 __rcs._M_data(_M_data()); 313 _M_data(_M_local_data); 314 } 315 else 316 { 317 _CharT* __tmp_ptr = _M_data(); 318 _M_data(__rcs._M_data()); 319 __rcs._M_data(__tmp_ptr); 320 _M_capacity(__rcs._M_allocated_capacity); 321 } 322 __rcs._M_capacity(__tmp_capacity); 323 } 324 325 const size_type __tmp_length = _M_length(); 326 _M_length(__rcs._M_length()); 327 __rcs._M_length(__tmp_length); 328 } 329 330 template<typename _CharT, typename _Traits, typename _Alloc> 331 _CharT* 332 __sso_string_base<_CharT, _Traits, _Alloc>:: 333 _M_create(size_type& __capacity, size_type __old_capacity) 334 { 335 // _GLIBCXX_RESOLVE_LIB_DEFECTS 336 // 83. String::npos vs. string::max_size() 337 if (__capacity > _M_max_size()) 338 std::__throw_length_error(__N("__sso_string_base::_M_create")); 339 340 // The below implements an exponential growth policy, necessary to 341 // meet amortized linear time requirements of the library: see 342 // http://gcc.gnu.org/ml/libstdc++/2001-07/msg00085.html. 343 if (__capacity > __old_capacity && __capacity < 2 * __old_capacity) 344 { 345 __capacity = 2 * __old_capacity; 346 // Never allocate a string bigger than max_size. 347 if (__capacity > _M_max_size()) 348 __capacity = _M_max_size(); 349 } 350 351 // NB: Need an array of char_type[__capacity], plus a terminating 352 // null char_type() element. 353 return _M_get_allocator().allocate(__capacity + 1); 354 } 355 356 template<typename _CharT, typename _Traits, typename _Alloc> 357 __sso_string_base<_CharT, _Traits, _Alloc>:: 358 __sso_string_base(const _Alloc& __a) 359 : _M_dataplus(__a, _M_local_data) 360 { _M_set_length_no_wipe(0); } 361 362 template<typename _CharT, typename _Traits, typename _Alloc> 363 __sso_string_base<_CharT, _Traits, _Alloc>:: 364 __sso_string_base(const __sso_string_base& __rcs) 365 : _M_dataplus(__rcs._M_get_allocator(), _M_local_data) 366 { _M_construct(__rcs._M_data(), __rcs._M_data() + __rcs._M_length()); } 367 368 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 369 template<typename _CharT, typename _Traits, typename _Alloc> 370 __sso_string_base<_CharT, _Traits, _Alloc>:: 371 __sso_string_base(__sso_string_base&& __rcs) 372 : _M_dataplus(__rcs._M_get_allocator(), _M_local_data) 373 { 374 if (__rcs._M_is_local()) 375 { 376 if (__rcs._M_length()) 377 traits_type::copy(_M_local_data, __rcs._M_local_data, 378 _S_local_capacity + 1); 379 } 380 else 381 { 382 _M_data(__rcs._M_data()); 383 _M_capacity(__rcs._M_allocated_capacity); 384 } 385 386 _M_length(__rcs._M_length()); 387 __rcs._M_length(0); 388 __rcs._M_data(__rcs._M_local_data); 389 } 390 #endif 391 392 template<typename _CharT, typename _Traits, typename _Alloc> 393 __sso_string_base<_CharT, _Traits, _Alloc>:: 394 __sso_string_base(size_type __n, _CharT __c, const _Alloc& __a) 395 : _M_dataplus(__a, _M_local_data) 396 { _M_construct(__n, __c); } 397 398 template<typename _CharT, typename _Traits, typename _Alloc> 399 template<typename _InputIterator> 400 __sso_string_base<_CharT, _Traits, _Alloc>:: 401 __sso_string_base(_InputIterator __beg, _InputIterator __end, 402 const _Alloc& __a) 403 : _M_dataplus(__a, _M_local_data) 404 { _M_construct(__beg, __end); } 405 406 // NB: This is the special case for Input Iterators, used in 407 // istreambuf_iterators, etc. 408 // Input Iterators have a cost structure very different from 409 // pointers, calling for a different coding style. 410 template<typename _CharT, typename _Traits, typename _Alloc> 411 template<typename _InIterator> 412 void 413 __sso_string_base<_CharT, _Traits, _Alloc>:: 414 _M_construct(_InIterator __beg, _InIterator __end, 415 std::input_iterator_tag) 416 { 417 size_type __len = 0; 418 size_type __capacity = size_type(_S_local_capacity); 419 420 while (__beg != __end && __len < __capacity) 421 { 422 _M_data()[__len++] = *__beg; 423 ++__beg; 424 } 425 426 __try 427 { 428 while (__beg != __end) 429 { 430 if (__len == __capacity) 431 { 432 // Allocate more space. 433 __capacity = __len + 1; 434 _CharT* __another = _M_create(__capacity, __len); 435 this->_S_copy(__another, _M_data(), __len); 436 _M_dispose(); 437 _M_data(__another); 438 _M_capacity(__capacity); 439 } 440 _M_data()[__len++] = *__beg; 441 ++__beg; 442 } 443 } 444 __catch(...) 445 { 446 _M_dispose(); 447 __throw_exception_again; 448 } 449 450 _M_set_length_no_wipe(__len); 451 } 452 453 template<typename _CharT, typename _Traits, typename _Alloc> 454 template<typename _InIterator> 455 void 456 __sso_string_base<_CharT, _Traits, _Alloc>:: 457 _M_construct(_InIterator __beg, _InIterator __end, 458 std::forward_iterator_tag) 459 { 460 // NB: Not required, but considered best practice. 461 if (__is_null_pointer(__beg) && __beg != __end) 462 std::__throw_logic_error(__N("__sso_string_base::" 463 "_M_construct null not valid")); 464 465 size_type __dnew = static_cast<size_type>(std::distance(__beg, __end)); 466 467 if (__dnew > size_type(_S_local_capacity)) 468 { 469 _M_data(_M_create(__dnew, size_type(0))); 470 _M_capacity(__dnew); 471 } 472 473 // Check for out_of_range and length_error exceptions. 474 __try 475 { this->_S_copy_chars(_M_data(), __beg, __end); } 476 __catch(...) 477 { 478 _M_dispose(); 479 __throw_exception_again; 480 } 481 482 _M_set_length_no_wipe(__dnew); 483 } 484 485 template<typename _CharT, typename _Traits, typename _Alloc> 486 void 487 __sso_string_base<_CharT, _Traits, _Alloc>:: 488 _M_construct(size_type __n, _CharT __c) 489 { 490 if (__n > size_type(_S_local_capacity)) 491 { 492 _M_data(_M_create(__n, size_type(0))); 493 _M_capacity(__n); 494 } 495 496 if (__n) 497 this->_S_assign(_M_data(), __n, __c); 498 499 _M_set_length_no_wipe(__n); 500 } 501 502 template<typename _CharT, typename _Traits, typename _Alloc> 503 void 504 __sso_string_base<_CharT, _Traits, _Alloc>:: 505 _M_assign(const __sso_string_base& __rcs) 506 { 507 if (this != &__rcs) 508 { 509 const size_type __rsize = __rcs._M_length(); 510 const size_type __capacity = _M_capacity(); 511 512 if (__rsize > __capacity) 513 { 514 size_type __new_capacity = __rsize; 515 _CharT* __tmp = _M_create(__new_capacity, __capacity); 516 _M_dispose(); 517 _M_data(__tmp); 518 _M_capacity(__new_capacity); 519 } 520 521 if (__rsize) 522 this->_S_copy(_M_data(), __rcs._M_data(), __rsize); 523 524 _M_set_length(__rsize); 525 } 526 } 527 528 template<typename _CharT, typename _Traits, typename _Alloc> 529 void 530 __sso_string_base<_CharT, _Traits, _Alloc>:: 531 _M_reserve(size_type __res) 532 { 533 // Make sure we don't shrink below the current size. 534 if (__res < _M_length()) 535 __res = _M_length(); 536 537 const size_type __capacity = _M_capacity(); 538 if (__res != __capacity) 539 { 540 if (__res > __capacity 541 || __res > size_type(_S_local_capacity)) 542 { 543 _CharT* __tmp = _M_create(__res, __capacity); 544 this->_S_copy(__tmp, _M_data(), _M_length() + 1); 545 _M_dispose(); 546 _M_data(__tmp); 547 _M_capacity(__res); 548 } 549 else if (!_M_is_local()) 550 { 551 this->_S_copy(_M_local_data, _M_data(), _M_length() + 1); 552 _M_destroy(__capacity); 553 _M_data(_M_local_data); 554 } 555 } 556 } 557 558 template<typename _CharT, typename _Traits, typename _Alloc> 559 void 560 __sso_string_base<_CharT, _Traits, _Alloc>:: 561 _M_mutate(size_type __pos, size_type __len1, const _CharT* __s, 562 size_type __len2) 563 { 564 const size_type __how_much = _M_length() - __pos - __len1; 565 566 size_type __new_capacity = _M_length() + __len2 - __len1; 567 _CharT* __r = _M_create(__new_capacity, _M_capacity()); 568 569 if (__pos) 570 this->_S_copy(__r, _M_data(), __pos); 571 if (__s && __len2) 572 this->_S_copy(__r + __pos, __s, __len2); 573 if (__how_much) 574 this->_S_copy(__r + __pos + __len2, 575 _M_data() + __pos + __len1, __how_much); 576 577 _M_dispose(); 578 _M_data(__r); 579 _M_capacity(__new_capacity); 580 } 581 582 template<typename _CharT, typename _Traits, typename _Alloc> 583 void 584 __sso_string_base<_CharT, _Traits, _Alloc>:: 585 _M_erase(size_type __pos, size_type __n) 586 { 587 const size_type __how_much = _M_length() - __pos - __n; 588 589 if (__how_much && __n) 590 this->_S_move(_M_data() + __pos, _M_data() + __pos + __n, __how_much); 591 592 _M_set_length(_M_length() - __n); 593 } 594 595 _GLIBCXX_END_NAMESPACE_VERSION 596 } // namespace 597 598 #endif /* _SSO_STRING_BASE_H */ 599
