ilist.h revision e14d81deeb6bb3404ffee5e59ecb88304f112f4a
1//==-- llvm/ADT/ilist.h - Intrusive Linked List Template ---------*- C++ -*-==// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file defines classes to implement an intrusive doubly linked list class 11// (i.e. each node of the list must contain a next and previous field for the 12// list. 13// 14// The ilist_traits trait class is used to gain access to the next and previous 15// fields of the node type that the list is instantiated with. If it is not 16// specialized, the list defaults to using the getPrev(), getNext() method calls 17// to get the next and previous pointers. 18// 19// The ilist class itself, should be a plug in replacement for list, assuming 20// that the nodes contain next/prev pointers. This list replacement does not 21// provide a constant time size() method, so be careful to use empty() when you 22// really want to know if it's empty. 23// 24// The ilist class is implemented by allocating a 'tail' node when the list is 25// created (using ilist_traits<>::createSentinel()). This tail node is 26// absolutely required because the user must be able to compute end()-1. Because 27// of this, users of the direct next/prev links will see an extra link on the 28// end of the list, which should be ignored. 29// 30// Requirements for a user of this list: 31// 32// 1. The user must provide {g|s}et{Next|Prev} methods, or specialize 33// ilist_traits to provide an alternate way of getting and setting next and 34// prev links. 35// 36//===----------------------------------------------------------------------===// 37 38#ifndef LLVM_ADT_ILIST_H 39#define LLVM_ADT_ILIST_H 40 41#include "llvm/ADT/iterator.h" 42#include <cassert> 43#include <cstdlib> 44 45namespace llvm { 46 47template<typename NodeTy, typename Traits> class iplist; 48template<typename NodeTy> class ilist_iterator; 49 50// Template traits for intrusive list. By specializing this template class, you 51// can change what next/prev fields are used to store the links... 52template<typename NodeTy> 53struct ilist_traits { 54 static NodeTy *getPrev(NodeTy *N) { return N->getPrev(); } 55 static NodeTy *getNext(NodeTy *N) { return N->getNext(); } 56 static const NodeTy *getPrev(const NodeTy *N) { return N->getPrev(); } 57 static const NodeTy *getNext(const NodeTy *N) { return N->getNext(); } 58 59 static void setPrev(NodeTy *N, NodeTy *Prev) { N->setPrev(Prev); } 60 static void setNext(NodeTy *N, NodeTy *Next) { N->setNext(Next); } 61 62 static NodeTy *createNode(const NodeTy &V) { return new NodeTy(V); } 63 static void deleteNode(NodeTy *V) { delete V; } 64 65 static NodeTy *createSentinel() { return new NodeTy(); } 66 static void destroySentinel(NodeTy *N) { delete N; } 67 68 void addNodeToList(NodeTy *NTy) {} 69 void removeNodeFromList(NodeTy *NTy) {} 70 void transferNodesFromList(iplist<NodeTy, ilist_traits> &L2, 71 ilist_iterator<NodeTy> first, 72 ilist_iterator<NodeTy> last) {} 73}; 74 75// Const traits are the same as nonconst traits... 76template<typename Ty> 77struct ilist_traits<const Ty> : public ilist_traits<Ty> {}; 78 79 80//===----------------------------------------------------------------------===// 81// ilist_iterator<Node> - Iterator for intrusive list. 82// 83template<typename NodeTy> 84class ilist_iterator 85 : public bidirectional_iterator<NodeTy, ptrdiff_t> { 86 typedef ilist_traits<NodeTy> Traits; 87 typedef bidirectional_iterator<NodeTy, ptrdiff_t> super; 88 89public: 90 typedef size_t size_type; 91 typedef typename super::pointer pointer; 92 typedef typename super::reference reference; 93private: 94 pointer NodePtr; 95public: 96 97 ilist_iterator(pointer NP) : NodePtr(NP) {} 98 ilist_iterator(reference NR) : NodePtr(&NR) {} 99 ilist_iterator() : NodePtr(0) {} 100 101 // This is templated so that we can allow constructing a const iterator from 102 // a nonconst iterator... 103 template<class node_ty> 104 ilist_iterator(const ilist_iterator<node_ty> &RHS) 105 : NodePtr(RHS.getNodePtrUnchecked()) {} 106 107 // This is templated so that we can allow assigning to a const iterator from 108 // a nonconst iterator... 109 template<class node_ty> 110 const ilist_iterator &operator=(const ilist_iterator<node_ty> &RHS) { 111 NodePtr = RHS.getNodePtrUnchecked(); 112 return *this; 113 } 114 115 // Accessors... 116 operator pointer() const { 117 assert(Traits::getNext(NodePtr) != 0 && "Dereferencing end()!"); 118 return NodePtr; 119 } 120 121 reference operator*() const { 122 assert(Traits::getNext(NodePtr) != 0 && "Dereferencing end()!"); 123 return *NodePtr; 124 } 125 pointer operator->() const { return &operator*(); } 126 127 // Comparison operators 128 bool operator==(const ilist_iterator &RHS) const { 129 return NodePtr == RHS.NodePtr; 130 } 131 bool operator!=(const ilist_iterator &RHS) const { 132 return NodePtr != RHS.NodePtr; 133 } 134 135 // Increment and decrement operators... 136 ilist_iterator &operator--() { // predecrement - Back up 137 NodePtr = Traits::getPrev(NodePtr); 138 assert(Traits::getNext(NodePtr) && "--'d off the beginning of an ilist!"); 139 return *this; 140 } 141 ilist_iterator &operator++() { // preincrement - Advance 142 NodePtr = Traits::getNext(NodePtr); 143 assert(NodePtr && "++'d off the end of an ilist!"); 144 return *this; 145 } 146 ilist_iterator operator--(int) { // postdecrement operators... 147 ilist_iterator tmp = *this; 148 --*this; 149 return tmp; 150 } 151 ilist_iterator operator++(int) { // postincrement operators... 152 ilist_iterator tmp = *this; 153 ++*this; 154 return tmp; 155 } 156 157 // Internal interface, do not use... 158 pointer getNodePtrUnchecked() const { return NodePtr; } 159}; 160 161// do not implement. this is to catch errors when people try to use 162// them as random access iterators 163template<typename T> 164void operator-(int, ilist_iterator<T>); 165template<typename T> 166void operator-(ilist_iterator<T>,int); 167 168template<typename T> 169void operator+(int, ilist_iterator<T>); 170template<typename T> 171void operator+(ilist_iterator<T>,int); 172 173// operator!=/operator== - Allow mixed comparisons without dereferencing 174// the iterator, which could very likely be pointing to end(). 175template<typename T> 176bool operator!=(const T* LHS, const ilist_iterator<const T> &RHS) { 177 return LHS != RHS.getNodePtrUnchecked(); 178} 179template<typename T> 180bool operator==(const T* LHS, const ilist_iterator<const T> &RHS) { 181 return LHS == RHS.getNodePtrUnchecked(); 182} 183template<typename T> 184bool operator!=(T* LHS, const ilist_iterator<T> &RHS) { 185 return LHS != RHS.getNodePtrUnchecked(); 186} 187template<typename T> 188bool operator==(T* LHS, const ilist_iterator<T> &RHS) { 189 return LHS == RHS.getNodePtrUnchecked(); 190} 191 192 193// Allow ilist_iterators to convert into pointers to a node automatically when 194// used by the dyn_cast, cast, isa mechanisms... 195 196template<typename From> struct simplify_type; 197 198template<typename NodeTy> struct simplify_type<ilist_iterator<NodeTy> > { 199 typedef NodeTy* SimpleType; 200 201 static SimpleType getSimplifiedValue(const ilist_iterator<NodeTy> &Node) { 202 return &*Node; 203 } 204}; 205template<typename NodeTy> struct simplify_type<const ilist_iterator<NodeTy> > { 206 typedef NodeTy* SimpleType; 207 208 static SimpleType getSimplifiedValue(const ilist_iterator<NodeTy> &Node) { 209 return &*Node; 210 } 211}; 212 213 214//===----------------------------------------------------------------------===// 215// 216/// iplist - The subset of list functionality that can safely be used on nodes 217/// of polymorphic types, i.e. a heterogenous list with a common base class that 218/// holds the next/prev pointers. The only state of the list itself is a single 219/// pointer to the head of the list. 220/// 221/// This list can be in one of three interesting states: 222/// 1. The list may be completely unconstructed. In this case, the head 223/// pointer is null. When in this form, any query for an iterator (e.g. 224/// begin() or end()) causes the list to transparently change to state #2. 225/// 2. The list may be empty, but contain a sentinal for the end iterator. This 226/// sentinal is created by the Traits::createSentinel method and is a link 227/// in the list. When the list is empty, the pointer in the iplist points 228/// to the sentinal. Once the sentinal is constructed, it 229/// is not destroyed until the list is. 230/// 3. The list may contain actual objects in it, which are stored as a doubly 231/// linked list of nodes. One invariant of the list is that the predecessor 232/// of the first node in the list always points to the last node in the list, 233/// and the successor pointer for the sentinal (which always stays at the 234/// end of the list) is always null. 235/// 236template<typename NodeTy, typename Traits=ilist_traits<NodeTy> > 237class iplist : public Traits { 238 mutable NodeTy *Head; 239 240 // Use the prev node pointer of 'head' as the tail pointer. This is really a 241 // circularly linked list where we snip the 'next' link from the sentinel node 242 // back to the first node in the list (to preserve assertions about going off 243 // the end of the list). 244 NodeTy *getTail() { return getPrev(Head); } 245 const NodeTy *getTail() const { return getPrev(Head); } 246 void setTail(NodeTy *N) const { setPrev(Head, N); } 247 248 /// CreateLazySentinal - This method verifies whether the sentinal for the 249 /// list has been created and lazily makes it if not. 250 void CreateLazySentinal() const { 251 if (Head != 0) return; 252 Head = Traits::createSentinel(); 253 setNext(Head, 0); 254 setTail(Head); 255 } 256 257 static bool op_less(NodeTy &L, NodeTy &R) { return L < R; } 258 static bool op_equal(NodeTy &L, NodeTy &R) { return L == R; } 259 260 // No fundamental reason why iplist can't by copyable, but the default 261 // copy/copy-assign won't do. 262 iplist(const iplist &); // do not implement 263 void operator=(const iplist &); // do not implement 264 265public: 266 typedef NodeTy *pointer; 267 typedef const NodeTy *const_pointer; 268 typedef NodeTy &reference; 269 typedef const NodeTy &const_reference; 270 typedef NodeTy value_type; 271 typedef ilist_iterator<NodeTy> iterator; 272 typedef ilist_iterator<const NodeTy> const_iterator; 273 typedef size_t size_type; 274 typedef ptrdiff_t difference_type; 275 typedef std::reverse_iterator<const_iterator> const_reverse_iterator; 276 typedef std::reverse_iterator<iterator> reverse_iterator; 277 278 iplist() : Head(0) {} 279 ~iplist() { 280 if (!Head) return; 281 clear(); 282 Traits::destroySentinel(getTail()); 283 } 284 285 // Iterator creation methods. 286 iterator begin() { 287 CreateLazySentinal(); 288 return iterator(Head); 289 } 290 const_iterator begin() const { 291 CreateLazySentinal(); 292 return const_iterator(Head); 293 } 294 iterator end() { 295 CreateLazySentinal(); 296 return iterator(getTail()); 297 } 298 const_iterator end() const { 299 CreateLazySentinal(); 300 return const_iterator(getTail()); 301 } 302 303 // reverse iterator creation methods. 304 reverse_iterator rbegin() { return reverse_iterator(end()); } 305 const_reverse_iterator rbegin() const{ return const_reverse_iterator(end()); } 306 reverse_iterator rend() { return reverse_iterator(begin()); } 307 const_reverse_iterator rend() const { return const_reverse_iterator(begin());} 308 309 310 // Miscellaneous inspection routines. 311 size_type max_size() const { return size_type(-1); } 312 bool empty() const { return Head == 0 || Head == getTail(); } 313 314 // Front and back accessor functions... 315 reference front() { 316 assert(!empty() && "Called front() on empty list!"); 317 return *Head; 318 } 319 const_reference front() const { 320 assert(!empty() && "Called front() on empty list!"); 321 return *Head; 322 } 323 reference back() { 324 assert(!empty() && "Called back() on empty list!"); 325 return *getPrev(getTail()); 326 } 327 const_reference back() const { 328 assert(!empty() && "Called back() on empty list!"); 329 return *getPrev(getTail()); 330 } 331 332 void swap(iplist &RHS) { 333 abort(); // Swap does not use list traits callback correctly yet! 334 std::swap(Head, RHS.Head); 335 } 336 337 iterator insert(iterator where, NodeTy *New) { 338 NodeTy *CurNode = where.getNodePtrUnchecked(), *PrevNode = getPrev(CurNode); 339 setNext(New, CurNode); 340 setPrev(New, PrevNode); 341 342 if (CurNode != Head) // Is PrevNode off the beginning of the list? 343 setNext(PrevNode, New); 344 else 345 Head = New; 346 setPrev(CurNode, New); 347 348 addNodeToList(New); // Notify traits that we added a node... 349 return New; 350 } 351 352 NodeTy *remove(iterator &IT) { 353 assert(IT != end() && "Cannot remove end of list!"); 354 NodeTy *Node = &*IT; 355 NodeTy *NextNode = getNext(Node); 356 NodeTy *PrevNode = getPrev(Node); 357 358 if (Node != Head) // Is PrevNode off the beginning of the list? 359 setNext(PrevNode, NextNode); 360 else 361 Head = NextNode; 362 setPrev(NextNode, PrevNode); 363 IT = NextNode; 364 removeNodeFromList(Node); // Notify traits that we removed a node... 365 366 // Set the next/prev pointers of the current node to null. This isn't 367 // strictly required, but this catches errors where a node is removed from 368 // an ilist (and potentially deleted) with iterators still pointing at it. 369 // When those iterators are incremented or decremented, they will assert on 370 // the null next/prev pointer instead of "usually working". 371 setNext(Node, 0); 372 setPrev(Node, 0); 373 return Node; 374 } 375 376 NodeTy *remove(const iterator &IT) { 377 iterator MutIt = IT; 378 return remove(MutIt); 379 } 380 381 // erase - remove a node from the controlled sequence... and delete it. 382 iterator erase(iterator where) { 383 deleteNode(remove(where)); 384 return where; 385 } 386 387 388private: 389 // transfer - The heart of the splice function. Move linked list nodes from 390 // [first, last) into position. 391 // 392 void transfer(iterator position, iplist &L2, iterator first, iterator last) { 393 assert(first != last && "Should be checked by callers"); 394 395 if (position != last) { 396 // Note: we have to be careful about the case when we move the first node 397 // in the list. This node is the list sentinel node and we can't move it. 398 NodeTy *ThisSentinel = getTail(); 399 setTail(0); 400 NodeTy *L2Sentinel = L2.getTail(); 401 L2.setTail(0); 402 403 // Remove [first, last) from its old position. 404 NodeTy *First = &*first, *Prev = getPrev(First); 405 NodeTy *Next = last.getNodePtrUnchecked(), *Last = getPrev(Next); 406 if (Prev) 407 setNext(Prev, Next); 408 else 409 L2.Head = Next; 410 setPrev(Next, Prev); 411 412 // Splice [first, last) into its new position. 413 NodeTy *PosNext = position.getNodePtrUnchecked(); 414 NodeTy *PosPrev = getPrev(PosNext); 415 416 // Fix head of list... 417 if (PosPrev) 418 setNext(PosPrev, First); 419 else 420 Head = First; 421 setPrev(First, PosPrev); 422 423 // Fix end of list... 424 setNext(Last, PosNext); 425 setPrev(PosNext, Last); 426 427 transferNodesFromList(L2, First, PosNext); 428 429 // Now that everything is set, restore the pointers to the list sentinals. 430 L2.setTail(L2Sentinel); 431 setTail(ThisSentinel); 432 } 433 } 434 435public: 436 437 //===----------------------------------------------------------------------=== 438 // Functionality derived from other functions defined above... 439 // 440 441 size_type size() const { 442 if (Head == 0) return 0; // Don't require construction of sentinal if empty. 443#if __GNUC__ == 2 444 // GCC 2.95 has a broken std::distance 445 size_type Result = 0; 446 std::distance(begin(), end(), Result); 447 return Result; 448#else 449 return std::distance(begin(), end()); 450#endif 451 } 452 453 iterator erase(iterator first, iterator last) { 454 while (first != last) 455 first = erase(first); 456 return last; 457 } 458 459 void clear() { if (Head) erase(begin(), end()); } 460 461 // Front and back inserters... 462 void push_front(NodeTy *val) { insert(begin(), val); } 463 void push_back(NodeTy *val) { insert(end(), val); } 464 void pop_front() { 465 assert(!empty() && "pop_front() on empty list!"); 466 erase(begin()); 467 } 468 void pop_back() { 469 assert(!empty() && "pop_back() on empty list!"); 470 iterator t = end(); erase(--t); 471 } 472 473 // Special forms of insert... 474 template<class InIt> void insert(iterator where, InIt first, InIt last) { 475 for (; first != last; ++first) insert(where, *first); 476 } 477 478 // Splice members - defined in terms of transfer... 479 void splice(iterator where, iplist &L2) { 480 if (!L2.empty()) 481 transfer(where, L2, L2.begin(), L2.end()); 482 } 483 void splice(iterator where, iplist &L2, iterator first) { 484 iterator last = first; ++last; 485 if (where == first || where == last) return; // No change 486 transfer(where, L2, first, last); 487 } 488 void splice(iterator where, iplist &L2, iterator first, iterator last) { 489 if (first != last) transfer(where, L2, first, last); 490 } 491 492 493 494 //===----------------------------------------------------------------------=== 495 // High-Level Functionality that shouldn't really be here, but is part of list 496 // 497 498 // These two functions are actually called remove/remove_if in list<>, but 499 // they actually do the job of erase, rename them accordingly. 500 // 501 void erase(const NodeTy &val) { 502 for (iterator I = begin(), E = end(); I != E; ) { 503 iterator next = I; ++next; 504 if (*I == val) erase(I); 505 I = next; 506 } 507 } 508 template<class Pr1> void erase_if(Pr1 pred) { 509 for (iterator I = begin(), E = end(); I != E; ) { 510 iterator next = I; ++next; 511 if (pred(*I)) erase(I); 512 I = next; 513 } 514 } 515 516 template<class Pr2> void unique(Pr2 pred) { 517 if (empty()) return; 518 for (iterator I = begin(), E = end(), Next = begin(); ++Next != E;) { 519 if (pred(*I)) 520 erase(Next); 521 else 522 I = Next; 523 Next = I; 524 } 525 } 526 void unique() { unique(op_equal); } 527 528 template<class Pr3> void merge(iplist &right, Pr3 pred) { 529 iterator first1 = begin(), last1 = end(); 530 iterator first2 = right.begin(), last2 = right.end(); 531 while (first1 != last1 && first2 != last2) 532 if (pred(*first2, *first1)) { 533 iterator next = first2; 534 transfer(first1, right, first2, ++next); 535 first2 = next; 536 } else { 537 ++first1; 538 } 539 if (first2 != last2) transfer(last1, right, first2, last2); 540 } 541 void merge(iplist &right) { return merge(right, op_less); } 542 543 template<class Pr3> void sort(Pr3 pred); 544 void sort() { sort(op_less); } 545 void reverse(); 546}; 547 548 549template<typename NodeTy> 550struct ilist : public iplist<NodeTy> { 551 typedef typename iplist<NodeTy>::size_type size_type; 552 typedef typename iplist<NodeTy>::iterator iterator; 553 554 ilist() {} 555 ilist(const ilist &right) { 556 insert(this->begin(), right.begin(), right.end()); 557 } 558 explicit ilist(size_type count) { 559 insert(this->begin(), count, NodeTy()); 560 } 561 ilist(size_type count, const NodeTy &val) { 562 insert(this->begin(), count, val); 563 } 564 template<class InIt> ilist(InIt first, InIt last) { 565 insert(this->begin(), first, last); 566 } 567 568 569 // Forwarding functions: A workaround for GCC 2.95 which does not correctly 570 // support 'using' declarations to bring a hidden member into scope. 571 // 572 iterator insert(iterator a, NodeTy *b){ return iplist<NodeTy>::insert(a, b); } 573 void push_front(NodeTy *a) { iplist<NodeTy>::push_front(a); } 574 void push_back(NodeTy *a) { iplist<NodeTy>::push_back(a); } 575 576 577 // Main implementation here - Insert for a node passed by value... 578 iterator insert(iterator where, const NodeTy &val) { 579 return insert(where, createNode(val)); 580 } 581 582 583 // Front and back inserters... 584 void push_front(const NodeTy &val) { insert(this->begin(), val); } 585 void push_back(const NodeTy &val) { insert(this->end(), val); } 586 587 // Special forms of insert... 588 template<class InIt> void insert(iterator where, InIt first, InIt last) { 589 for (; first != last; ++first) insert(where, *first); 590 } 591 void insert(iterator where, size_type count, const NodeTy &val) { 592 for (; count != 0; --count) insert(where, val); 593 } 594 595 // Assign special forms... 596 void assign(size_type count, const NodeTy &val) { 597 iterator I = this->begin(); 598 for (; I != this->end() && count != 0; ++I, --count) 599 *I = val; 600 if (count != 0) 601 insert(this->end(), val, val); 602 else 603 erase(I, this->end()); 604 } 605 template<class InIt> void assign(InIt first1, InIt last1) { 606 iterator first2 = this->begin(), last2 = this->end(); 607 for ( ; first1 != last1 && first2 != last2; ++first1, ++first2) 608 *first1 = *first2; 609 if (first2 == last2) 610 erase(first1, last1); 611 else 612 insert(last1, first2, last2); 613 } 614 615 616 // Resize members... 617 void resize(size_type newsize, NodeTy val) { 618 iterator i = this->begin(); 619 size_type len = 0; 620 for ( ; i != this->end() && len < newsize; ++i, ++len) /* empty*/ ; 621 622 if (len == newsize) 623 erase(i, this->end()); 624 else // i == end() 625 insert(this->end(), newsize - len, val); 626 } 627 void resize(size_type newsize) { resize(newsize, NodeTy()); } 628}; 629 630} // End llvm namespace 631 632namespace std { 633 // Ensure that swap uses the fast list swap... 634 template<class Ty> 635 void swap(llvm::iplist<Ty> &Left, llvm::iplist<Ty> &Right) { 636 Left.swap(Right); 637 } 638} // End 'std' extensions... 639 640#endif // LLVM_ADT_ILIST_H 641