1 // Map implementation -*- C++ -*- 2 3 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 4 // 2011 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 /* 27 * 28 * Copyright (c) 1994 29 * Hewlett-Packard Company 30 * 31 * Permission to use, copy, modify, distribute and sell this software 32 * and its documentation for any purpose is hereby granted without fee, 33 * provided that the above copyright notice appear in all copies and 34 * that both that copyright notice and this permission notice appear 35 * in supporting documentation. Hewlett-Packard Company makes no 36 * representations about the suitability of this software for any 37 * purpose. It is provided "as is" without express or implied warranty. 38 * 39 * 40 * Copyright (c) 1996,1997 41 * Silicon Graphics Computer Systems, Inc. 42 * 43 * Permission to use, copy, modify, distribute and sell this software 44 * and its documentation for any purpose is hereby granted without fee, 45 * provided that the above copyright notice appear in all copies and 46 * that both that copyright notice and this permission notice appear 47 * in supporting documentation. Silicon Graphics makes no 48 * representations about the suitability of this software for any 49 * purpose. It is provided "as is" without express or implied warranty. 50 */ 51 52 /** @file bits/stl_map.h 53 * This is an internal header file, included by other library headers. 54 * Do not attempt to use it directly. @headername{map} 55 */ 56 57 #ifndef _STL_MAP_H 58 #define _STL_MAP_H 1 59 60 #include <bits/functexcept.h> 61 #include <bits/concept_check.h> 62 #include <initializer_list> 63 64 namespace std _GLIBCXX_VISIBILITY(default) 65 { 66 _GLIBCXX_BEGIN_NAMESPACE_CONTAINER 67 68 /** 69 * @brief A standard container made up of (key,value) pairs, which can be 70 * retrieved based on a key, in logarithmic time. 71 * 72 * @ingroup associative_containers 73 * 74 * Meets the requirements of a <a href="tables.html#65">container</a>, a 75 * <a href="tables.html#66">reversible container</a>, and an 76 * <a href="tables.html#69">associative container</a> (using unique keys). 77 * For a @c map<Key,T> the key_type is Key, the mapped_type is T, and the 78 * value_type is std::pair<const Key,T>. 79 * 80 * Maps support bidirectional iterators. 81 * 82 * The private tree data is declared exactly the same way for map and 83 * multimap; the distinction is made entirely in how the tree functions are 84 * called (*_unique versus *_equal, same as the standard). 85 */ 86 template <typename _Key, typename _Tp, typename _Compare = std::less<_Key>, 87 typename _Alloc = std::allocator<std::pair<const _Key, _Tp> > > 88 class map 89 { 90 public: 91 typedef _Key key_type; 92 typedef _Tp mapped_type; 93 typedef std::pair<const _Key, _Tp> value_type; 94 typedef _Compare key_compare; 95 typedef _Alloc allocator_type; 96 97 private: 98 // concept requirements 99 typedef typename _Alloc::value_type _Alloc_value_type; 100 __glibcxx_class_requires(_Tp, _SGIAssignableConcept) 101 __glibcxx_class_requires4(_Compare, bool, _Key, _Key, 102 _BinaryFunctionConcept) 103 __glibcxx_class_requires2(value_type, _Alloc_value_type, _SameTypeConcept) 104 105 public: 106 class value_compare 107 : public std::binary_function<value_type, value_type, bool> 108 { 109 friend class map<_Key, _Tp, _Compare, _Alloc>; 110 protected: 111 _Compare comp; 112 113 value_compare(_Compare __c) 114 : comp(__c) { } 115 116 public: 117 bool operator()(const value_type& __x, const value_type& __y) const 118 { return comp(__x.first, __y.first); } 119 }; 120 121 private: 122 /// This turns a red-black tree into a [multi]map. 123 typedef typename _Alloc::template rebind<value_type>::other 124 _Pair_alloc_type; 125 126 typedef _Rb_tree<key_type, value_type, _Select1st<value_type>, 127 key_compare, _Pair_alloc_type> _Rep_type; 128 129 /// The actual tree structure. 130 _Rep_type _M_t; 131 132 public: 133 // many of these are specified differently in ISO, but the following are 134 // "functionally equivalent" 135 typedef typename _Pair_alloc_type::pointer pointer; 136 typedef typename _Pair_alloc_type::const_pointer const_pointer; 137 typedef typename _Pair_alloc_type::reference reference; 138 typedef typename _Pair_alloc_type::const_reference const_reference; 139 typedef typename _Rep_type::iterator iterator; 140 typedef typename _Rep_type::const_iterator const_iterator; 141 typedef typename _Rep_type::size_type size_type; 142 typedef typename _Rep_type::difference_type difference_type; 143 typedef typename _Rep_type::reverse_iterator reverse_iterator; 144 typedef typename _Rep_type::const_reverse_iterator const_reverse_iterator; 145 146 // [23.3.1.1] construct/copy/destroy 147 // (get_allocator() is normally listed in this section, but seems to have 148 // been accidentally omitted in the printed standard) 149 /** 150 * @brief Default constructor creates no elements. 151 */ 152 map() 153 : _M_t() { } 154 155 /** 156 * @brief Creates a %map with no elements. 157 * @param comp A comparison object. 158 * @param a An allocator object. 159 */ 160 explicit 161 map(const _Compare& __comp, 162 const allocator_type& __a = allocator_type()) 163 : _M_t(__comp, __a) { } 164 165 /** 166 * @brief %Map copy constructor. 167 * @param x A %map of identical element and allocator types. 168 * 169 * The newly-created %map uses a copy of the allocation object 170 * used by @a x. 171 */ 172 map(const map& __x) 173 : _M_t(__x._M_t) { } 174 175 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 176 /** 177 * @brief %Map move constructor. 178 * @param x A %map of identical element and allocator types. 179 * 180 * The newly-created %map contains the exact contents of @a x. 181 * The contents of @a x are a valid, but unspecified %map. 182 */ 183 map(map&& __x) 184 : _M_t(std::move(__x._M_t)) { } 185 186 /** 187 * @brief Builds a %map from an initializer_list. 188 * @param l An initializer_list. 189 * @param comp A comparison object. 190 * @param a An allocator object. 191 * 192 * Create a %map consisting of copies of the elements in the 193 * initializer_list @a l. 194 * This is linear in N if the range is already sorted, and NlogN 195 * otherwise (where N is @a l.size()). 196 */ 197 map(initializer_list<value_type> __l, 198 const _Compare& __c = _Compare(), 199 const allocator_type& __a = allocator_type()) 200 : _M_t(__c, __a) 201 { _M_t._M_insert_unique(__l.begin(), __l.end()); } 202 #endif 203 204 /** 205 * @brief Builds a %map from a range. 206 * @param first An input iterator. 207 * @param last An input iterator. 208 * 209 * Create a %map consisting of copies of the elements from [first,last). 210 * This is linear in N if the range is already sorted, and NlogN 211 * otherwise (where N is distance(first,last)). 212 */ 213 template<typename _InputIterator> 214 map(_InputIterator __first, _InputIterator __last) 215 : _M_t() 216 { _M_t._M_insert_unique(__first, __last); } 217 218 /** 219 * @brief Builds a %map from a range. 220 * @param first An input iterator. 221 * @param last An input iterator. 222 * @param comp A comparison functor. 223 * @param a An allocator object. 224 * 225 * Create a %map consisting of copies of the elements from [first,last). 226 * This is linear in N if the range is already sorted, and NlogN 227 * otherwise (where N is distance(first,last)). 228 */ 229 template<typename _InputIterator> 230 map(_InputIterator __first, _InputIterator __last, 231 const _Compare& __comp, 232 const allocator_type& __a = allocator_type()) 233 : _M_t(__comp, __a) 234 { _M_t._M_insert_unique(__first, __last); } 235 236 // FIXME There is no dtor declared, but we should have something 237 // generated by Doxygen. I don't know what tags to add to this 238 // paragraph to make that happen: 239 /** 240 * The dtor only erases the elements, and note that if the elements 241 * themselves are pointers, the pointed-to memory is not touched in any 242 * way. Managing the pointer is the user's responsibility. 243 */ 244 245 /** 246 * @brief %Map assignment operator. 247 * @param x A %map of identical element and allocator types. 248 * 249 * All the elements of @a x are copied, but unlike the copy constructor, 250 * the allocator object is not copied. 251 */ 252 map& 253 operator=(const map& __x) 254 { 255 _M_t = __x._M_t; 256 return *this; 257 } 258 259 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 260 /** 261 * @brief %Map move assignment operator. 262 * @param x A %map of identical element and allocator types. 263 * 264 * The contents of @a x are moved into this map (without copying). 265 * @a x is a valid, but unspecified %map. 266 */ 267 map& 268 operator=(map&& __x) 269 { 270 // NB: DR 1204. 271 // NB: DR 675. 272 this->clear(); 273 this->swap(__x); 274 return *this; 275 } 276 277 /** 278 * @brief %Map list assignment operator. 279 * @param l An initializer_list. 280 * 281 * This function fills a %map with copies of the elements in the 282 * initializer list @a l. 283 * 284 * Note that the assignment completely changes the %map and 285 * that the resulting %map's size is the same as the number 286 * of elements assigned. Old data may be lost. 287 */ 288 map& 289 operator=(initializer_list<value_type> __l) 290 { 291 this->clear(); 292 this->insert(__l.begin(), __l.end()); 293 return *this; 294 } 295 #endif 296 297 /// Get a copy of the memory allocation object. 298 allocator_type 299 get_allocator() const 300 { return _M_t.get_allocator(); } 301 302 // iterators 303 /** 304 * Returns a read/write iterator that points to the first pair in the 305 * %map. 306 * Iteration is done in ascending order according to the keys. 307 */ 308 iterator 309 begin() 310 { return _M_t.begin(); } 311 312 /** 313 * Returns a read-only (constant) iterator that points to the first pair 314 * in the %map. Iteration is done in ascending order according to the 315 * keys. 316 */ 317 const_iterator 318 begin() const 319 { return _M_t.begin(); } 320 321 /** 322 * Returns a read/write iterator that points one past the last 323 * pair in the %map. Iteration is done in ascending order 324 * according to the keys. 325 */ 326 iterator 327 end() 328 { return _M_t.end(); } 329 330 /** 331 * Returns a read-only (constant) iterator that points one past the last 332 * pair in the %map. Iteration is done in ascending order according to 333 * the keys. 334 */ 335 const_iterator 336 end() const 337 { return _M_t.end(); } 338 339 /** 340 * Returns a read/write reverse iterator that points to the last pair in 341 * the %map. Iteration is done in descending order according to the 342 * keys. 343 */ 344 reverse_iterator 345 rbegin() 346 { return _M_t.rbegin(); } 347 348 /** 349 * Returns a read-only (constant) reverse iterator that points to the 350 * last pair in the %map. Iteration is done in descending order 351 * according to the keys. 352 */ 353 const_reverse_iterator 354 rbegin() const 355 { return _M_t.rbegin(); } 356 357 /** 358 * Returns a read/write reverse iterator that points to one before the 359 * first pair in the %map. Iteration is done in descending order 360 * according to the keys. 361 */ 362 reverse_iterator 363 rend() 364 { return _M_t.rend(); } 365 366 /** 367 * Returns a read-only (constant) reverse iterator that points to one 368 * before the first pair in the %map. Iteration is done in descending 369 * order according to the keys. 370 */ 371 const_reverse_iterator 372 rend() const 373 { return _M_t.rend(); } 374 375 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 376 /** 377 * Returns a read-only (constant) iterator that points to the first pair 378 * in the %map. Iteration is done in ascending order according to the 379 * keys. 380 */ 381 const_iterator 382 cbegin() const 383 { return _M_t.begin(); } 384 385 /** 386 * Returns a read-only (constant) iterator that points one past the last 387 * pair in the %map. Iteration is done in ascending order according to 388 * the keys. 389 */ 390 const_iterator 391 cend() const 392 { return _M_t.end(); } 393 394 /** 395 * Returns a read-only (constant) reverse iterator that points to the 396 * last pair in the %map. Iteration is done in descending order 397 * according to the keys. 398 */ 399 const_reverse_iterator 400 crbegin() const 401 { return _M_t.rbegin(); } 402 403 /** 404 * Returns a read-only (constant) reverse iterator that points to one 405 * before the first pair in the %map. Iteration is done in descending 406 * order according to the keys. 407 */ 408 const_reverse_iterator 409 crend() const 410 { return _M_t.rend(); } 411 #endif 412 413 // capacity 414 /** Returns true if the %map is empty. (Thus begin() would equal 415 * end().) 416 */ 417 bool 418 empty() const 419 { return _M_t.empty(); } 420 421 /** Returns the size of the %map. */ 422 size_type 423 size() const 424 { return _M_t.size(); } 425 426 /** Returns the maximum size of the %map. */ 427 size_type 428 max_size() const 429 { return _M_t.max_size(); } 430 431 // [23.3.1.2] element access 432 /** 433 * @brief Subscript ( @c [] ) access to %map data. 434 * @param k The key for which data should be retrieved. 435 * @return A reference to the data of the (key,data) %pair. 436 * 437 * Allows for easy lookup with the subscript ( @c [] ) 438 * operator. Returns data associated with the key specified in 439 * subscript. If the key does not exist, a pair with that key 440 * is created using default values, which is then returned. 441 * 442 * Lookup requires logarithmic time. 443 */ 444 mapped_type& 445 operator[](const key_type& __k) 446 { 447 // concept requirements 448 __glibcxx_function_requires(_DefaultConstructibleConcept<mapped_type>) 449 450 iterator __i = lower_bound(__k); 451 // __i->first is greater than or equivalent to __k. 452 if (__i == end() || key_comp()(__k, (*__i).first)) 453 __i = insert(__i, value_type(__k, mapped_type())); 454 return (*__i).second; 455 } 456 457 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 458 mapped_type& 459 operator[](key_type&& __k) 460 { 461 // concept requirements 462 __glibcxx_function_requires(_DefaultConstructibleConcept<mapped_type>) 463 464 iterator __i = lower_bound(__k); 465 // __i->first is greater than or equivalent to __k. 466 if (__i == end() || key_comp()(__k, (*__i).first)) 467 __i = insert(__i, std::make_pair(std::move(__k), mapped_type())); 468 return (*__i).second; 469 } 470 #endif 471 472 // _GLIBCXX_RESOLVE_LIB_DEFECTS 473 // DR 464. Suggestion for new member functions in standard containers. 474 /** 475 * @brief Access to %map data. 476 * @param k The key for which data should be retrieved. 477 * @return A reference to the data whose key is equivalent to @a k, if 478 * such a data is present in the %map. 479 * @throw std::out_of_range If no such data is present. 480 */ 481 mapped_type& 482 at(const key_type& __k) 483 { 484 iterator __i = lower_bound(__k); 485 if (__i == end() || key_comp()(__k, (*__i).first)) 486 __throw_out_of_range(__N("map::at")); 487 return (*__i).second; 488 } 489 490 const mapped_type& 491 at(const key_type& __k) const 492 { 493 const_iterator __i = lower_bound(__k); 494 if (__i == end() || key_comp()(__k, (*__i).first)) 495 __throw_out_of_range(__N("map::at")); 496 return (*__i).second; 497 } 498 499 // modifiers 500 /** 501 * @brief Attempts to insert a std::pair into the %map. 502 503 * @param x Pair to be inserted (see std::make_pair for easy creation 504 * of pairs). 505 506 * @return A pair, of which the first element is an iterator that 507 * points to the possibly inserted pair, and the second is 508 * a bool that is true if the pair was actually inserted. 509 * 510 * This function attempts to insert a (key, value) %pair into the %map. 511 * A %map relies on unique keys and thus a %pair is only inserted if its 512 * first element (the key) is not already present in the %map. 513 * 514 * Insertion requires logarithmic time. 515 */ 516 std::pair<iterator, bool> 517 insert(const value_type& __x) 518 { return _M_t._M_insert_unique(__x); } 519 520 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 521 template<typename _Pair, typename = typename 522 std::enable_if<std::is_convertible<_Pair, 523 value_type>::value>::type> 524 std::pair<iterator, bool> 525 insert(_Pair&& __x) 526 { return _M_t._M_insert_unique(std::forward<_Pair>(__x)); } 527 #endif 528 529 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 530 /** 531 * @brief Attempts to insert a list of std::pairs into the %map. 532 * @param list A std::initializer_list<value_type> of pairs to be 533 * inserted. 534 * 535 * Complexity similar to that of the range constructor. 536 */ 537 void 538 insert(std::initializer_list<value_type> __list) 539 { insert(__list.begin(), __list.end()); } 540 #endif 541 542 /** 543 * @brief Attempts to insert a std::pair into the %map. 544 * @param position An iterator that serves as a hint as to where the 545 * pair should be inserted. 546 * @param x Pair to be inserted (see std::make_pair for easy creation 547 * of pairs). 548 * @return An iterator that points to the element with key of @a x (may 549 * or may not be the %pair passed in). 550 * 551 552 * This function is not concerned about whether the insertion 553 * took place, and thus does not return a boolean like the 554 * single-argument insert() does. Note that the first 555 * parameter is only a hint and can potentially improve the 556 * performance of the insertion process. A bad hint would 557 * cause no gains in efficiency. 558 * 559 * See 560 * http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt07ch17.html 561 * for more on @a hinting. 562 * 563 * Insertion requires logarithmic time (if the hint is not taken). 564 */ 565 iterator 566 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 567 insert(const_iterator __position, const value_type& __x) 568 #else 569 insert(iterator __position, const value_type& __x) 570 #endif 571 { return _M_t._M_insert_unique_(__position, __x); } 572 573 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 574 template<typename _Pair, typename = typename 575 std::enable_if<std::is_convertible<_Pair, 576 value_type>::value>::type> 577 iterator 578 insert(const_iterator __position, _Pair&& __x) 579 { return _M_t._M_insert_unique_(__position, 580 std::forward<_Pair>(__x)); } 581 #endif 582 583 /** 584 * @brief Template function that attempts to insert a range of elements. 585 * @param first Iterator pointing to the start of the range to be 586 * inserted. 587 * @param last Iterator pointing to the end of the range. 588 * 589 * Complexity similar to that of the range constructor. 590 */ 591 template<typename _InputIterator> 592 void 593 insert(_InputIterator __first, _InputIterator __last) 594 { _M_t._M_insert_unique(__first, __last); } 595 596 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 597 // _GLIBCXX_RESOLVE_LIB_DEFECTS 598 // DR 130. Associative erase should return an iterator. 599 /** 600 * @brief Erases an element from a %map. 601 * @param position An iterator pointing to the element to be erased. 602 * @return An iterator pointing to the element immediately following 603 * @a position prior to the element being erased. If no such 604 * element exists, end() is returned. 605 * 606 * This function erases an element, pointed to by the given 607 * iterator, from a %map. Note that this function only erases 608 * the element, and that if the element is itself a pointer, 609 * the pointed-to memory is not touched in any way. Managing 610 * the pointer is the user's responsibility. 611 */ 612 iterator 613 erase(const_iterator __position) 614 { return _M_t.erase(__position); } 615 616 // LWG 2059. 617 iterator 618 erase(iterator __position) 619 { return _M_t.erase(__position); } 620 #else 621 /** 622 * @brief Erases an element from a %map. 623 * @param position An iterator pointing to the element to be erased. 624 * 625 * This function erases an element, pointed to by the given 626 * iterator, from a %map. Note that this function only erases 627 * the element, and that if the element is itself a pointer, 628 * the pointed-to memory is not touched in any way. Managing 629 * the pointer is the user's responsibility. 630 */ 631 void 632 erase(iterator __position) 633 { _M_t.erase(__position); } 634 #endif 635 636 /** 637 * @brief Erases elements according to the provided key. 638 * @param x Key of element to be erased. 639 * @return The number of elements erased. 640 * 641 * This function erases all the elements located by the given key from 642 * a %map. 643 * Note that this function only erases the element, and that if 644 * the element is itself a pointer, the pointed-to memory is not touched 645 * in any way. Managing the pointer is the user's responsibility. 646 */ 647 size_type 648 erase(const key_type& __x) 649 { return _M_t.erase(__x); } 650 651 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 652 // _GLIBCXX_RESOLVE_LIB_DEFECTS 653 // DR 130. Associative erase should return an iterator. 654 /** 655 * @brief Erases a [first,last) range of elements from a %map. 656 * @param first Iterator pointing to the start of the range to be 657 * erased. 658 * @param last Iterator pointing to the end of the range to be erased. 659 * @return The iterator @a last. 660 * 661 * This function erases a sequence of elements from a %map. 662 * Note that this function only erases the element, and that if 663 * the element is itself a pointer, the pointed-to memory is not touched 664 * in any way. Managing the pointer is the user's responsibility. 665 */ 666 iterator 667 erase(const_iterator __first, const_iterator __last) 668 { return _M_t.erase(__first, __last); } 669 #else 670 /** 671 * @brief Erases a [first,last) range of elements from a %map. 672 * @param first Iterator pointing to the start of the range to be 673 * erased. 674 * @param last Iterator pointing to the end of the range to be erased. 675 * 676 * This function erases a sequence of elements from a %map. 677 * Note that this function only erases the element, and that if 678 * the element is itself a pointer, the pointed-to memory is not touched 679 * in any way. Managing the pointer is the user's responsibility. 680 */ 681 void 682 erase(iterator __first, iterator __last) 683 { _M_t.erase(__first, __last); } 684 #endif 685 686 /** 687 * @brief Swaps data with another %map. 688 * @param x A %map of the same element and allocator types. 689 * 690 * This exchanges the elements between two maps in constant 691 * time. (It is only swapping a pointer, an integer, and an 692 * instance of the @c Compare type (which itself is often 693 * stateless and empty), so it should be quite fast.) Note 694 * that the global std::swap() function is specialized such 695 * that std::swap(m1,m2) will feed to this function. 696 */ 697 void 698 swap(map& __x) 699 { _M_t.swap(__x._M_t); } 700 701 /** 702 * Erases all elements in a %map. Note that this function only 703 * erases the elements, and that if the elements themselves are 704 * pointers, the pointed-to memory is not touched in any way. 705 * Managing the pointer is the user's responsibility. 706 */ 707 void 708 clear() 709 { _M_t.clear(); } 710 711 // observers 712 /** 713 * Returns the key comparison object out of which the %map was 714 * constructed. 715 */ 716 key_compare 717 key_comp() const 718 { return _M_t.key_comp(); } 719 720 /** 721 * Returns a value comparison object, built from the key comparison 722 * object out of which the %map was constructed. 723 */ 724 value_compare 725 value_comp() const 726 { return value_compare(_M_t.key_comp()); } 727 728 // [23.3.1.3] map operations 729 /** 730 * @brief Tries to locate an element in a %map. 731 * @param x Key of (key, value) %pair to be located. 732 * @return Iterator pointing to sought-after element, or end() if not 733 * found. 734 * 735 * This function takes a key and tries to locate the element with which 736 * the key matches. If successful the function returns an iterator 737 * pointing to the sought after %pair. If unsuccessful it returns the 738 * past-the-end ( @c end() ) iterator. 739 */ 740 iterator 741 find(const key_type& __x) 742 { return _M_t.find(__x); } 743 744 /** 745 * @brief Tries to locate an element in a %map. 746 * @param x Key of (key, value) %pair to be located. 747 * @return Read-only (constant) iterator pointing to sought-after 748 * element, or end() if not found. 749 * 750 * This function takes a key and tries to locate the element with which 751 * the key matches. If successful the function returns a constant 752 * iterator pointing to the sought after %pair. If unsuccessful it 753 * returns the past-the-end ( @c end() ) iterator. 754 */ 755 const_iterator 756 find(const key_type& __x) const 757 { return _M_t.find(__x); } 758 759 /** 760 * @brief Finds the number of elements with given key. 761 * @param x Key of (key, value) pairs to be located. 762 * @return Number of elements with specified key. 763 * 764 * This function only makes sense for multimaps; for map the result will 765 * either be 0 (not present) or 1 (present). 766 */ 767 size_type 768 count(const key_type& __x) const 769 { return _M_t.find(__x) == _M_t.end() ? 0 : 1; } 770 771 /** 772 * @brief Finds the beginning of a subsequence matching given key. 773 * @param x Key of (key, value) pair to be located. 774 * @return Iterator pointing to first element equal to or greater 775 * than key, or end(). 776 * 777 * This function returns the first element of a subsequence of elements 778 * that matches the given key. If unsuccessful it returns an iterator 779 * pointing to the first element that has a greater value than given key 780 * or end() if no such element exists. 781 */ 782 iterator 783 lower_bound(const key_type& __x) 784 { return _M_t.lower_bound(__x); } 785 786 /** 787 * @brief Finds the beginning of a subsequence matching given key. 788 * @param x Key of (key, value) pair to be located. 789 * @return Read-only (constant) iterator pointing to first element 790 * equal to or greater than key, or end(). 791 * 792 * This function returns the first element of a subsequence of elements 793 * that matches the given key. If unsuccessful it returns an iterator 794 * pointing to the first element that has a greater value than given key 795 * or end() if no such element exists. 796 */ 797 const_iterator 798 lower_bound(const key_type& __x) const 799 { return _M_t.lower_bound(__x); } 800 801 /** 802 * @brief Finds the end of a subsequence matching given key. 803 * @param x Key of (key, value) pair to be located. 804 * @return Iterator pointing to the first element 805 * greater than key, or end(). 806 */ 807 iterator 808 upper_bound(const key_type& __x) 809 { return _M_t.upper_bound(__x); } 810 811 /** 812 * @brief Finds the end of a subsequence matching given key. 813 * @param x Key of (key, value) pair to be located. 814 * @return Read-only (constant) iterator pointing to first iterator 815 * greater than key, or end(). 816 */ 817 const_iterator 818 upper_bound(const key_type& __x) const 819 { return _M_t.upper_bound(__x); } 820 821 /** 822 * @brief Finds a subsequence matching given key. 823 * @param x Key of (key, value) pairs to be located. 824 * @return Pair of iterators that possibly points to the subsequence 825 * matching given key. 826 * 827 * This function is equivalent to 828 * @code 829 * std::make_pair(c.lower_bound(val), 830 * c.upper_bound(val)) 831 * @endcode 832 * (but is faster than making the calls separately). 833 * 834 * This function probably only makes sense for multimaps. 835 */ 836 std::pair<iterator, iterator> 837 equal_range(const key_type& __x) 838 { return _M_t.equal_range(__x); } 839 840 /** 841 * @brief Finds a subsequence matching given key. 842 * @param x Key of (key, value) pairs to be located. 843 * @return Pair of read-only (constant) iterators that possibly points 844 * to the subsequence matching given key. 845 * 846 * This function is equivalent to 847 * @code 848 * std::make_pair(c.lower_bound(val), 849 * c.upper_bound(val)) 850 * @endcode 851 * (but is faster than making the calls separately). 852 * 853 * This function probably only makes sense for multimaps. 854 */ 855 std::pair<const_iterator, const_iterator> 856 equal_range(const key_type& __x) const 857 { return _M_t.equal_range(__x); } 858 859 template<typename _K1, typename _T1, typename _C1, typename _A1> 860 friend bool 861 operator==(const map<_K1, _T1, _C1, _A1>&, 862 const map<_K1, _T1, _C1, _A1>&); 863 864 template<typename _K1, typename _T1, typename _C1, typename _A1> 865 friend bool 866 operator<(const map<_K1, _T1, _C1, _A1>&, 867 const map<_K1, _T1, _C1, _A1>&); 868 }; 869 870 /** 871 * @brief Map equality comparison. 872 * @param x A %map. 873 * @param y A %map of the same type as @a x. 874 * @return True iff the size and elements of the maps are equal. 875 * 876 * This is an equivalence relation. It is linear in the size of the 877 * maps. Maps are considered equivalent if their sizes are equal, 878 * and if corresponding elements compare equal. 879 */ 880 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc> 881 inline bool 882 operator==(const map<_Key, _Tp, _Compare, _Alloc>& __x, 883 const map<_Key, _Tp, _Compare, _Alloc>& __y) 884 { return __x._M_t == __y._M_t; } 885 886 /** 887 * @brief Map ordering relation. 888 * @param x A %map. 889 * @param y A %map of the same type as @a x. 890 * @return True iff @a x is lexicographically less than @a y. 891 * 892 * This is a total ordering relation. It is linear in the size of the 893 * maps. The elements must be comparable with @c <. 894 * 895 * See std::lexicographical_compare() for how the determination is made. 896 */ 897 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc> 898 inline bool 899 operator<(const map<_Key, _Tp, _Compare, _Alloc>& __x, 900 const map<_Key, _Tp, _Compare, _Alloc>& __y) 901 { return __x._M_t < __y._M_t; } 902 903 /// Based on operator== 904 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc> 905 inline bool 906 operator!=(const map<_Key, _Tp, _Compare, _Alloc>& __x, 907 const map<_Key, _Tp, _Compare, _Alloc>& __y) 908 { return !(__x == __y); } 909 910 /// Based on operator< 911 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc> 912 inline bool 913 operator>(const map<_Key, _Tp, _Compare, _Alloc>& __x, 914 const map<_Key, _Tp, _Compare, _Alloc>& __y) 915 { return __y < __x; } 916 917 /// Based on operator< 918 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc> 919 inline bool 920 operator<=(const map<_Key, _Tp, _Compare, _Alloc>& __x, 921 const map<_Key, _Tp, _Compare, _Alloc>& __y) 922 { return !(__y < __x); } 923 924 /// Based on operator< 925 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc> 926 inline bool 927 operator>=(const map<_Key, _Tp, _Compare, _Alloc>& __x, 928 const map<_Key, _Tp, _Compare, _Alloc>& __y) 929 { return !(__x < __y); } 930 931 /// See std::map::swap(). 932 template<typename _Key, typename _Tp, typename _Compare, typename _Alloc> 933 inline void 934 swap(map<_Key, _Tp, _Compare, _Alloc>& __x, 935 map<_Key, _Tp, _Compare, _Alloc>& __y) 936 { __x.swap(__y); } 937 938 _GLIBCXX_END_NAMESPACE_CONTAINER 939 } // namespace std 940 941 #endif /* _STL_MAP_H */ 942