1 // Map implementation -*- C++ -*- 2 3 // Copyright (C) 2001, 2002, 2004 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 2, 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 // You should have received a copy of the GNU General Public License along 17 // with this library; see the file COPYING. If not, write to the Free 18 // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, 19 // USA. 20 21 // As a special exception, you may use this file as part of a free software 22 // library without restriction. Specifically, if other files instantiate 23 // templates or use macros or inline functions from this file, or you compile 24 // this file and link it with other files to produce an executable, this 25 // file does not by itself cause the resulting executable to be covered by 26 // the GNU General Public License. This exception does not however 27 // invalidate any other reasons why the executable file might be covered by 28 // the GNU General Public License. 29 30 /* 31 * 32 * Copyright (c) 1994 33 * Hewlett-Packard Company 34 * 35 * Permission to use, copy, modify, distribute and sell this software 36 * and its documentation for any purpose is hereby granted without fee, 37 * provided that the above copyright notice appear in all copies and 38 * that both that copyright notice and this permission notice appear 39 * in supporting documentation. Hewlett-Packard Company makes no 40 * representations about the suitability of this software for any 41 * purpose. It is provided "as is" without express or implied warranty. 42 * 43 * 44 * Copyright (c) 1996,1997 45 * Silicon Graphics Computer Systems, Inc. 46 * 47 * Permission to use, copy, modify, distribute and sell this software 48 * and its documentation for any purpose is hereby granted without fee, 49 * provided that the above copyright notice appear in all copies and 50 * that both that copyright notice and this permission notice appear 51 * in supporting documentation. Silicon Graphics makes no 52 * representations about the suitability of this software for any 53 * purpose. It is provided "as is" without express or implied warranty. 54 */ 55 56 /** @file stl_map.h 57 * This is an internal header file, included by other library headers. 58 * You should not attempt to use it directly. 59 */ 60 61 #ifndef _MAP_H 62 #define _MAP_H 1 63 64 #include <bits/concept_check.h> 65 66 namespace _GLIBCXX_STD 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 Containers 73 * @ingroup Assoc_containers 74 * 75 * Meets the requirements of a <a href="tables.html#65">container</a>, a 76 * <a href="tables.html#66">reversible container</a>, and an 77 * <a href="tables.html#69">associative container</a> (using unique keys). 78 * For a @c map<Key,T> the key_type is Key, the mapped_type is T, and the 79 * value_type is std::pair<const Key,T>. 80 * 81 * Maps support bidirectional iterators. 82 * 83 * @if maint 84 * The private tree data is declared exactly the same way for map and 85 * multimap; the distinction is made entirely in how the tree functions are 86 * called (*_unique versus *_equal, same as the standard). 87 * @endif 88 */ 89 template <typename _Key, typename _Tp, typename _Compare = less<_Key>, 90 typename _Alloc = allocator<pair<const _Key, _Tp> > > 91 class map 92 { 93 // concept requirements 94 __glibcxx_class_requires(_Tp, _SGIAssignableConcept) 95 __glibcxx_class_requires4(_Compare, bool, _Key, _Key, 96 _BinaryFunctionConcept) 97 98 public: 99 typedef _Key key_type; 100 typedef _Tp mapped_type; 101 typedef pair<const _Key, _Tp> value_type; 102 typedef _Compare key_compare; 103 104 class value_compare 105 : public binary_function<value_type, value_type, bool> 106 { 107 friend class map<_Key,_Tp,_Compare,_Alloc>; 108 protected: 109 _Compare comp; 110 111 value_compare(_Compare __c) 112 : comp(__c) { } 113 114 public: 115 bool operator()(const value_type& __x, const value_type& __y) const 116 { return comp(__x.first, __y.first); } 117 }; 118 119 private: 120 /// @if maint This turns a red-black tree into a [multi]map. @endif 121 typedef _Rb_tree<key_type, value_type, 122 _Select1st<value_type>, key_compare, _Alloc> _Rep_type; 123 /// @if maint The actual tree structure. @endif 124 _Rep_type _M_t; 125 126 public: 127 // many of these are specified differently in ISO, but the following are 128 // "functionally equivalent" 129 typedef typename _Alloc::pointer pointer; 130 typedef typename _Alloc::const_pointer const_pointer; 131 typedef typename _Alloc::reference reference; 132 typedef typename _Alloc::const_reference const_reference; 133 typedef typename _Rep_type::allocator_type allocator_type; 134 typedef typename _Rep_type::iterator iterator; 135 typedef typename _Rep_type::const_iterator const_iterator; 136 typedef typename _Rep_type::size_type size_type; 137 typedef typename _Rep_type::difference_type difference_type; 138 typedef typename _Rep_type::reverse_iterator reverse_iterator; 139 typedef typename _Rep_type::const_reverse_iterator const_reverse_iterator; 140 141 // [23.3.1.1] construct/copy/destroy 142 // (get_allocator() is normally listed in this section, but seems to have 143 // been accidentally omitted in the printed standard) 144 /** 145 * @brief Default constructor creates no elements. 146 */ 147 map() 148 : _M_t(_Compare(), allocator_type()) { } 149 150 // for some reason this was made a separate function 151 /** 152 * @brief Default constructor creates no elements. 153 */ 154 explicit 155 map(const _Compare& __comp, const allocator_type& __a = allocator_type()) 156 : _M_t(__comp, __a) { } 157 158 /** 159 * @brief Map copy constructor. 160 * @param x A %map of identical element and allocator types. 161 * 162 * The newly-created %map uses a copy of the allocation object used 163 * by @a x. 164 */ 165 map(const map& __x) 166 : _M_t(__x._M_t) { } 167 168 /** 169 * @brief Builds a %map from a range. 170 * @param first An input iterator. 171 * @param last An input iterator. 172 * 173 * Create a %map consisting of copies of the elements from [first,last). 174 * This is linear in N if the range is already sorted, and NlogN 175 * otherwise (where N is distance(first,last)). 176 */ 177 template <typename _InputIterator> 178 map(_InputIterator __first, _InputIterator __last) 179 : _M_t(_Compare(), allocator_type()) 180 { _M_t.insert_unique(__first, __last); } 181 182 /** 183 * @brief Builds a %map from a range. 184 * @param first An input iterator. 185 * @param last An input iterator. 186 * @param comp A comparison functor. 187 * @param a An allocator object. 188 * 189 * Create a %map consisting of copies of the elements from [first,last). 190 * This is linear in N if the range is already sorted, and NlogN 191 * otherwise (where N is distance(first,last)). 192 */ 193 template <typename _InputIterator> 194 map(_InputIterator __first, _InputIterator __last, 195 const _Compare& __comp, const allocator_type& __a = allocator_type()) 196 : _M_t(__comp, __a) 197 { _M_t.insert_unique(__first, __last); } 198 199 // FIXME There is no dtor declared, but we should have something generated 200 // by Doxygen. I don't know what tags to add to this paragraph to make 201 // that happen: 202 /** 203 * The dtor only erases the elements, and note that if the elements 204 * themselves are pointers, the pointed-to memory is not touched in any 205 * way. Managing the pointer is the user's responsibilty. 206 */ 207 208 /** 209 * @brief Map assignment operator. 210 * @param x A %map of identical element and allocator types. 211 * 212 * All the elements of @a x are copied, but unlike the copy constructor, 213 * the allocator object is not copied. 214 */ 215 map& 216 operator=(const map& __x) 217 { 218 _M_t = __x._M_t; 219 return *this; 220 } 221 222 /// Get a copy of the memory allocation object. 223 allocator_type 224 get_allocator() const 225 { return _M_t.get_allocator(); } 226 227 // iterators 228 /** 229 * Returns a read/write iterator that points to the first pair in the 230 * %map. 231 * Iteration is done in ascending order according to the keys. 232 */ 233 iterator 234 begin() 235 { return _M_t.begin(); } 236 237 /** 238 * Returns a read-only (constant) iterator that points to the first pair 239 * in the %map. Iteration is done in ascending order according to the 240 * keys. 241 */ 242 const_iterator 243 begin() const 244 { return _M_t.begin(); } 245 246 /** 247 * Returns a read/write iterator that points one past the last pair in 248 * the %map. Iteration is done in ascending order according to the keys. 249 */ 250 iterator 251 end() 252 { return _M_t.end(); } 253 254 /** 255 * Returns a read-only (constant) iterator that points one past the last 256 * pair in the %map. Iteration is done in ascending order according to 257 * the keys. 258 */ 259 const_iterator 260 end() const 261 { return _M_t.end(); } 262 263 /** 264 * Returns a read/write reverse iterator that points to the last pair in 265 * the %map. Iteration is done in descending order according to the 266 * keys. 267 */ 268 reverse_iterator 269 rbegin() 270 { return _M_t.rbegin(); } 271 272 /** 273 * Returns a read-only (constant) reverse iterator that points to the 274 * last pair in the %map. Iteration is done in descending order 275 * according to the keys. 276 */ 277 const_reverse_iterator 278 rbegin() const 279 { return _M_t.rbegin(); } 280 281 /** 282 * Returns a read/write reverse iterator that points to one before the 283 * first pair in the %map. Iteration is done in descending order 284 * according to the keys. 285 */ 286 reverse_iterator 287 rend() 288 { return _M_t.rend(); } 289 290 /** 291 * Returns a read-only (constant) reverse iterator that points to one 292 * before the first pair in the %map. Iteration is done in descending 293 * order according to the keys. 294 */ 295 const_reverse_iterator 296 rend() const 297 { return _M_t.rend(); } 298 299 // capacity 300 /** Returns true if the %map is empty. (Thus begin() would equal 301 * end().) 302 */ 303 bool 304 empty() const 305 { return _M_t.empty(); } 306 307 /** Returns the size of the %map. */ 308 size_type 309 size() const 310 { return _M_t.size(); } 311 312 /** Returns the maximum size of the %map. */ 313 size_type 314 max_size() const 315 { return _M_t.max_size(); } 316 317 // [23.3.1.2] element access 318 /** 319 * @brief Subscript ( @c [] ) access to %map data. 320 * @param k The key for which data should be retrieved. 321 * @return A reference to the data of the (key,data) %pair. 322 * 323 * Allows for easy lookup with the subscript ( @c [] ) operator. Returns 324 * data associated with the key specified in subscript. If the key does 325 * not exist, a pair with that key is created using default values, which 326 * is then returned. 327 * 328 * Lookup requires logarithmic time. 329 */ 330 mapped_type& 331 operator[](const key_type& __k) 332 { 333 // concept requirements 334 __glibcxx_function_requires(_DefaultConstructibleConcept<mapped_type>) 335 336 iterator __i = lower_bound(__k); 337 // __i->first is greater than or equivalent to __k. 338 if (__i == end() || key_comp()(__k, (*__i).first)) 339 __i = insert(__i, value_type(__k, mapped_type())); 340 return (*__i).second; 341 } 342 343 // modifiers 344 /** 345 * @brief Attempts to insert a std::pair into the %map. 346 * @param x Pair to be inserted (see std::make_pair for easy creation of 347 * pairs). 348 * @return A pair, of which the first element is an iterator that points 349 * to the possibly inserted pair, and the second is a bool that 350 * is true if the pair was actually inserted. 351 * 352 * This function attempts to insert a (key, value) %pair into the %map. 353 * A %map relies on unique keys and thus a %pair is only inserted if its 354 * first element (the key) is not already present in the %map. 355 * 356 * Insertion requires logarithmic time. 357 */ 358 pair<iterator,bool> 359 insert(const value_type& __x) 360 { return _M_t.insert_unique(__x); } 361 362 /** 363 * @brief Attempts to insert a std::pair into the %map. 364 * @param position An iterator that serves as a hint as to where the 365 * pair should be inserted. 366 * @param x Pair to be inserted (see std::make_pair for easy creation of 367 * pairs). 368 * @return An iterator that points to the element with key of @a x (may 369 * or may not be the %pair passed in). 370 * 371 * This function is not concerned about whether the insertion took place, 372 * and thus does not return a boolean like the single-argument 373 * insert() does. Note that the first parameter is only a hint and can 374 * potentially improve the performance of the insertion process. A bad 375 * hint would cause no gains in efficiency. 376 * 377 * See http://gcc.gnu.org/onlinedocs/libstdc++/23_containers/howto.html#4 378 * for more on "hinting". 379 * 380 * Insertion requires logarithmic time (if the hint is not taken). 381 */ 382 iterator 383 insert(iterator position, const value_type& __x) 384 { return _M_t.insert_unique(position, __x); } 385 386 /** 387 * @brief A template function that attemps to insert a range of elements. 388 * @param first Iterator pointing to the start of the range to be 389 * inserted. 390 * @param last Iterator pointing to the end of the range. 391 * 392 * Complexity similar to that of the range constructor. 393 */ 394 template <typename _InputIterator> 395 void 396 insert(_InputIterator __first, _InputIterator __last) 397 { _M_t.insert_unique(__first, __last); } 398 399 /** 400 * @brief Erases an element from a %map. 401 * @param position An iterator pointing to the element to be erased. 402 * 403 * This function erases an element, pointed to by the given iterator, 404 * from a %map. Note that this function only erases the element, and 405 * that if the element is itself a pointer, the pointed-to memory is not 406 * touched in any way. Managing the pointer is the user's responsibilty. 407 */ 408 void 409 erase(iterator __position) 410 { _M_t.erase(__position); } 411 412 /** 413 * @brief Erases elements according to the provided key. 414 * @param x Key of element to be erased. 415 * @return The number of elements erased. 416 * 417 * This function erases all the elements located by the given key from 418 * a %map. 419 * Note that this function only erases the element, and that if 420 * the element is itself a pointer, the pointed-to memory is not touched 421 * in any way. Managing the pointer is the user's responsibilty. 422 */ 423 size_type 424 erase(const key_type& __x) 425 { return _M_t.erase(__x); } 426 427 /** 428 * @brief Erases a [first,last) range of elements from a %map. 429 * @param first Iterator pointing to the start of the range to be 430 * erased. 431 * @param last Iterator pointing to the end of the range to be erased. 432 * 433 * This function erases a sequence of elements from a %map. 434 * Note that this function only erases the element, and that if 435 * the element is itself a pointer, the pointed-to memory is not touched 436 * in any way. Managing the pointer is the user's responsibilty. 437 */ 438 void 439 erase(iterator __first, iterator __last) 440 { _M_t.erase(__first, __last); } 441 442 /** 443 * @brief Swaps data with another %map. 444 * @param x A %map of the same element and allocator types. 445 * 446 * This exchanges the elements between two maps in constant time. 447 * (It is only swapping a pointer, an integer, and an instance of 448 * the @c Compare type (which itself is often stateless and empty), so it 449 * should be quite fast.) 450 * Note that the global std::swap() function is specialized such that 451 * std::swap(m1,m2) will feed to this function. 452 */ 453 void 454 swap(map& __x) 455 { _M_t.swap(__x._M_t); } 456 457 /** 458 * Erases all elements in a %map. Note that this function only erases 459 * the elements, and that if the elements themselves are pointers, the 460 * pointed-to memory is not touched in any way. Managing the pointer is 461 * the user's responsibilty. 462 */ 463 void 464 clear() 465 { _M_t.clear(); } 466 467 // observers 468 /** 469 * Returns the key comparison object out of which the %map was 470 * constructed. 471 */ 472 key_compare 473 key_comp() const 474 { return _M_t.key_comp(); } 475 476 /** 477 * Returns a value comparison object, built from the key comparison 478 * object out of which the %map was constructed. 479 */ 480 value_compare 481 value_comp() const 482 { return value_compare(_M_t.key_comp()); } 483 484 // [23.3.1.3] map operations 485 /** 486 * @brief Tries to locate an element in a %map. 487 * @param x Key of (key, value) %pair to be located. 488 * @return Iterator pointing to sought-after element, or end() if not 489 * found. 490 * 491 * This function takes a key and tries to locate the element with which 492 * the key matches. If successful the function returns an iterator 493 * pointing to the sought after %pair. If unsuccessful it returns the 494 * past-the-end ( @c end() ) iterator. 495 */ 496 iterator 497 find(const key_type& __x) 498 { return _M_t.find(__x); } 499 500 /** 501 * @brief Tries to locate an element in a %map. 502 * @param x Key of (key, value) %pair to be located. 503 * @return Read-only (constant) iterator pointing to sought-after 504 * element, or end() if not found. 505 * 506 * This function takes a key and tries to locate the element with which 507 * the key matches. If successful the function returns a constant 508 * iterator pointing to the sought after %pair. If unsuccessful it 509 * returns the past-the-end ( @c end() ) iterator. 510 */ 511 const_iterator 512 find(const key_type& __x) const 513 { return _M_t.find(__x); } 514 515 /** 516 * @brief Finds the number of elements with given key. 517 * @param x Key of (key, value) pairs to be located. 518 * @return Number of elements with specified key. 519 * 520 * This function only makes sense for multimaps; for map the result will 521 * either be 0 (not present) or 1 (present). 522 */ 523 size_type 524 count(const key_type& __x) const 525 { return _M_t.find(__x) == _M_t.end() ? 0 : 1; } 526 527 /** 528 * @brief Finds the beginning of a subsequence matching given key. 529 * @param x Key of (key, value) pair to be located. 530 * @return Iterator pointing to first element equal to or greater 531 * than key, or end(). 532 * 533 * This function returns the first element of a subsequence of elements 534 * that matches the given key. If unsuccessful it returns an iterator 535 * pointing to the first element that has a greater value than given key 536 * or end() if no such element exists. 537 */ 538 iterator 539 lower_bound(const key_type& __x) 540 { return _M_t.lower_bound(__x); } 541 542 /** 543 * @brief Finds the beginning of a subsequence matching given key. 544 * @param x Key of (key, value) pair to be located. 545 * @return Read-only (constant) iterator pointing to first element 546 * equal to or greater than key, or end(). 547 * 548 * This function returns the first element of a subsequence of elements 549 * that matches the given key. If unsuccessful it returns an iterator 550 * pointing to the first element that has a greater value than given key 551 * or end() if no such element exists. 552 */ 553 const_iterator 554 lower_bound(const key_type& __x) const 555 { return _M_t.lower_bound(__x); } 556 557 /** 558 * @brief Finds the end of a subsequence matching given key. 559 * @param x Key of (key, value) pair to be located. 560 * @return Iterator pointing to the first element 561 * greater than key, or end(). 562 */ 563 iterator 564 upper_bound(const key_type& __x) 565 { return _M_t.upper_bound(__x); } 566 567 /** 568 * @brief Finds the end of a subsequence matching given key. 569 * @param x Key of (key, value) pair to be located. 570 * @return Read-only (constant) iterator pointing to first iterator 571 * greater than key, or end(). 572 */ 573 const_iterator 574 upper_bound(const key_type& __x) const 575 { return _M_t.upper_bound(__x); } 576 577 /** 578 * @brief Finds a subsequence matching given key. 579 * @param x Key of (key, value) pairs to be located. 580 * @return Pair of iterators that possibly points to the subsequence 581 * matching given key. 582 * 583 * This function is equivalent to 584 * @code 585 * std::make_pair(c.lower_bound(val), 586 * c.upper_bound(val)) 587 * @endcode 588 * (but is faster than making the calls separately). 589 * 590 * This function probably only makes sense for multimaps. 591 */ 592 pair<iterator,iterator> 593 equal_range(const key_type& __x) 594 { return _M_t.equal_range(__x); } 595 596 /** 597 * @brief Finds a subsequence matching given key. 598 * @param x Key of (key, value) pairs to be located. 599 * @return Pair of read-only (constant) iterators that possibly points 600 * to the subsequence matching given key. 601 * 602 * This function is equivalent to 603 * @code 604 * std::make_pair(c.lower_bound(val), 605 * c.upper_bound(val)) 606 * @endcode 607 * (but is faster than making the calls separately). 608 * 609 * This function probably only makes sense for multimaps. 610 */ 611 pair<const_iterator,const_iterator> 612 equal_range(const key_type& __x) const 613 { return _M_t.equal_range(__x); } 614 615 template <typename _K1, typename _T1, typename _C1, typename _A1> 616 friend bool 617 operator== (const map<_K1,_T1,_C1,_A1>&, 618 const map<_K1,_T1,_C1,_A1>&); 619 620 template <typename _K1, typename _T1, typename _C1, typename _A1> 621 friend bool 622 operator< (const map<_K1,_T1,_C1,_A1>&, 623 const map<_K1,_T1,_C1,_A1>&); 624 }; 625 626 /** 627 * @brief Map equality comparison. 628 * @param x A %map. 629 * @param y A %map of the same type as @a x. 630 * @return True iff the size and elements of the maps are equal. 631 * 632 * This is an equivalence relation. It is linear in the size of the 633 * maps. Maps are considered equivalent if their sizes are equal, 634 * and if corresponding elements compare equal. 635 */ 636 template <typename _Key, typename _Tp, typename _Compare, typename _Alloc> 637 inline bool 638 operator==(const map<_Key,_Tp,_Compare,_Alloc>& __x, 639 const map<_Key,_Tp,_Compare,_Alloc>& __y) 640 { return __x._M_t == __y._M_t; } 641 642 /** 643 * @brief Map ordering relation. 644 * @param x A %map. 645 * @param y A %map of the same type as @a x. 646 * @return True iff @a x is lexicographically less than @a y. 647 * 648 * This is a total ordering relation. It is linear in the size of the 649 * maps. The elements must be comparable with @c <. 650 * 651 * See std::lexicographical_compare() for how the determination is made. 652 */ 653 template <typename _Key, typename _Tp, typename _Compare, typename _Alloc> 654 inline bool 655 operator<(const map<_Key,_Tp,_Compare,_Alloc>& __x, 656 const map<_Key,_Tp,_Compare,_Alloc>& __y) 657 { return __x._M_t < __y._M_t; } 658 659 /// Based on operator== 660 template <typename _Key, typename _Tp, typename _Compare, typename _Alloc> 661 inline bool 662 operator!=(const map<_Key,_Tp,_Compare,_Alloc>& __x, 663 const map<_Key,_Tp,_Compare,_Alloc>& __y) 664 { return !(__x == __y); } 665 666 /// Based on operator< 667 template <typename _Key, typename _Tp, typename _Compare, typename _Alloc> 668 inline bool 669 operator>(const map<_Key,_Tp,_Compare,_Alloc>& __x, 670 const map<_Key,_Tp,_Compare,_Alloc>& __y) 671 { return __y < __x; } 672 673 /// Based on operator< 674 template <typename _Key, typename _Tp, typename _Compare, typename _Alloc> 675 inline bool 676 operator<=(const map<_Key,_Tp,_Compare,_Alloc>& __x, 677 const map<_Key,_Tp,_Compare,_Alloc>& __y) 678 { return !(__y < __x); } 679 680 /// Based on operator< 681 template <typename _Key, typename _Tp, typename _Compare, typename _Alloc> 682 inline bool 683 operator>=(const map<_Key,_Tp,_Compare,_Alloc>& __x, 684 const map<_Key,_Tp,_Compare,_Alloc>& __y) 685 { return !(__x < __y); } 686 687 /// See std::map::swap(). 688 template <typename _Key, typename _Tp, typename _Compare, typename _Alloc> 689 inline void 690 swap(map<_Key,_Tp,_Compare,_Alloc>& __x, map<_Key,_Tp,_Compare,_Alloc>& __y) 691 { __x.swap(__y); } 692 } // namespace std 693 694 #endif /* _MAP_H */ 695