ilist.h revision e21a6bae806d13e644a92b3df23e4d5b78bdb75c
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 44namespace llvm { 45 46template<typename NodeTy, typename Traits> class iplist; 47template<typename NodeTy> class ilist_iterator; 48 49/// ilist_nextprev_traits - A fragment for template traits for intrusive list 50/// that provides default next/prev implementations for common operations. 51/// 52template<typename NodeTy> 53struct ilist_nextprev_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 63/// ilist_sentinel_traits - A fragment for template traits for intrusive list 64/// that provides default sentinel implementations for common operations. 65/// 66template<typename NodeTy> 67struct ilist_sentinel_traits { 68 static NodeTy *createSentinel() { return new NodeTy(); } 69 static void destroySentinel(NodeTy *N) { delete N; } 70}; 71 72/// ilist_default_traits - Default template traits for intrusive list. 73/// By inheriting from this, you can easily use default implementations 74/// for all common operations. 75/// 76template<typename NodeTy> 77struct ilist_default_traits : ilist_nextprev_traits<NodeTy>, 78 ilist_sentinel_traits<NodeTy> { 79 static NodeTy *createNode(const NodeTy &V) { return new NodeTy(V); } 80 static void deleteNode(NodeTy *V) { delete V; } 81 82 void addNodeToList(NodeTy *) {} 83 void removeNodeFromList(NodeTy *) {} 84 void transferNodesFromList(ilist_default_traits & /*SrcTraits*/, 85 ilist_iterator<NodeTy> /*first*/, 86 ilist_iterator<NodeTy> /*last*/) {} 87}; 88 89// Template traits for intrusive list. By specializing this template class, you 90// can change what next/prev fields are used to store the links... 91template<typename NodeTy> 92struct ilist_traits : ilist_default_traits<NodeTy> {}; 93 94// Const traits are the same as nonconst traits... 95template<typename Ty> 96struct ilist_traits<const Ty> : public ilist_traits<Ty> {}; 97 98//===----------------------------------------------------------------------===// 99// ilist_iterator<Node> - Iterator for intrusive list. 100// 101template<typename NodeTy> 102class ilist_iterator 103 : public bidirectional_iterator<NodeTy, ptrdiff_t> { 104 105public: 106 typedef ilist_traits<NodeTy> Traits; 107 typedef bidirectional_iterator<NodeTy, ptrdiff_t> super; 108 109 typedef typename super::value_type value_type; 110 typedef typename super::difference_type difference_type; 111 typedef typename super::pointer pointer; 112 typedef typename super::reference reference; 113private: 114 pointer NodePtr; 115 116 // ilist_iterator is not a random-access iterator, but it has an 117 // implicit conversion to pointer-type, which is. Declare (but 118 // don't define) these functions as private to help catch 119 // accidental misuse. 120 void operator[](difference_type) const; 121 void operator+(difference_type) const; 122 void operator-(difference_type) const; 123 void operator+=(difference_type) const; 124 void operator-=(difference_type) const; 125 template<class T> void operator<(T) const; 126 template<class T> void operator<=(T) const; 127 template<class T> void operator>(T) const; 128 template<class T> void operator>=(T) const; 129 template<class T> void operator-(T) const; 130public: 131 132 ilist_iterator(pointer NP) : NodePtr(NP) {} 133 ilist_iterator(reference NR) : NodePtr(&NR) {} 134 ilist_iterator() : NodePtr(0) {} 135 136 // This is templated so that we can allow constructing a const iterator from 137 // a nonconst iterator... 138 template<class node_ty> 139 ilist_iterator(const ilist_iterator<node_ty> &RHS) 140 : NodePtr(RHS.getNodePtrUnchecked()) {} 141 142 // This is templated so that we can allow assigning to a const iterator from 143 // a nonconst iterator... 144 template<class node_ty> 145 const ilist_iterator &operator=(const ilist_iterator<node_ty> &RHS) { 146 NodePtr = RHS.getNodePtrUnchecked(); 147 return *this; 148 } 149 150 // Accessors... 151 operator pointer() const { 152 assert(Traits::getNext(NodePtr) != 0 && "Dereferencing end()!"); 153 return NodePtr; 154 } 155 156 reference operator*() const { 157 assert(Traits::getNext(NodePtr) != 0 && "Dereferencing end()!"); 158 return *NodePtr; 159 } 160 pointer operator->() const { return &operator*(); } 161 162 // Comparison operators 163 bool operator==(const ilist_iterator &RHS) const { 164 return NodePtr == RHS.NodePtr; 165 } 166 bool operator!=(const ilist_iterator &RHS) const { 167 return NodePtr != RHS.NodePtr; 168 } 169 170 // Increment and decrement operators... 171 ilist_iterator &operator--() { // predecrement - Back up 172 NodePtr = Traits::getPrev(NodePtr); 173 assert(Traits::getNext(NodePtr) && "--'d off the beginning of an ilist!"); 174 return *this; 175 } 176 ilist_iterator &operator++() { // preincrement - Advance 177 NodePtr = Traits::getNext(NodePtr); 178 assert(NodePtr && "++'d off the end of an ilist!"); 179 return *this; 180 } 181 ilist_iterator operator--(int) { // postdecrement operators... 182 ilist_iterator tmp = *this; 183 --*this; 184 return tmp; 185 } 186 ilist_iterator operator++(int) { // postincrement operators... 187 ilist_iterator tmp = *this; 188 ++*this; 189 return tmp; 190 } 191 192 // Internal interface, do not use... 193 pointer getNodePtrUnchecked() const { return NodePtr; } 194}; 195 196// do not implement. this is to catch errors when people try to use 197// them as random access iterators 198template<typename T> 199void operator-(int, ilist_iterator<T>); 200template<typename T> 201void operator-(ilist_iterator<T>,int); 202 203template<typename T> 204void operator+(int, ilist_iterator<T>); 205template<typename T> 206void operator+(ilist_iterator<T>,int); 207 208// operator!=/operator== - Allow mixed comparisons without dereferencing 209// the iterator, which could very likely be pointing to end(). 210template<typename T> 211bool operator!=(const T* LHS, const ilist_iterator<const T> &RHS) { 212 return LHS != RHS.getNodePtrUnchecked(); 213} 214template<typename T> 215bool operator==(const T* LHS, const ilist_iterator<const T> &RHS) { 216 return LHS == RHS.getNodePtrUnchecked(); 217} 218template<typename T> 219bool operator!=(T* LHS, const ilist_iterator<T> &RHS) { 220 return LHS != RHS.getNodePtrUnchecked(); 221} 222template<typename T> 223bool operator==(T* LHS, const ilist_iterator<T> &RHS) { 224 return LHS == RHS.getNodePtrUnchecked(); 225} 226 227 228// Allow ilist_iterators to convert into pointers to a node automatically when 229// used by the dyn_cast, cast, isa mechanisms... 230 231template<typename From> struct simplify_type; 232 233template<typename NodeTy> struct simplify_type<ilist_iterator<NodeTy> > { 234 typedef NodeTy* SimpleType; 235 236 static SimpleType getSimplifiedValue(const ilist_iterator<NodeTy> &Node) { 237 return &*Node; 238 } 239}; 240template<typename NodeTy> struct simplify_type<const ilist_iterator<NodeTy> > { 241 typedef NodeTy* SimpleType; 242 243 static SimpleType getSimplifiedValue(const ilist_iterator<NodeTy> &Node) { 244 return &*Node; 245 } 246}; 247 248 249//===----------------------------------------------------------------------===// 250// 251/// iplist - The subset of list functionality that can safely be used on nodes 252/// of polymorphic types, i.e. a heterogenous list with a common base class that 253/// holds the next/prev pointers. The only state of the list itself is a single 254/// pointer to the head of the list. 255/// 256/// This list can be in one of three interesting states: 257/// 1. The list may be completely unconstructed. In this case, the head 258/// pointer is null. When in this form, any query for an iterator (e.g. 259/// begin() or end()) causes the list to transparently change to state #2. 260/// 2. The list may be empty, but contain a sentinel for the end iterator. This 261/// sentinel is created by the Traits::createSentinel method and is a link 262/// in the list. When the list is empty, the pointer in the iplist points 263/// to the sentinel. Once the sentinel is constructed, it 264/// is not destroyed until the list is. 265/// 3. The list may contain actual objects in it, which are stored as a doubly 266/// linked list of nodes. One invariant of the list is that the predecessor 267/// of the first node in the list always points to the last node in the list, 268/// and the successor pointer for the sentinel (which always stays at the 269/// end of the list) is always null. 270/// 271template<typename NodeTy, typename Traits=ilist_traits<NodeTy> > 272class iplist : public Traits { 273 mutable NodeTy *Head; 274 275 // Use the prev node pointer of 'head' as the tail pointer. This is really a 276 // circularly linked list where we snip the 'next' link from the sentinel node 277 // back to the first node in the list (to preserve assertions about going off 278 // the end of the list). 279 NodeTy *getTail() { return this->getPrev(Head); } 280 const NodeTy *getTail() const { return this->getPrev(Head); } 281 void setTail(NodeTy *N) const { this->setPrev(Head, N); } 282 283 /// CreateLazySentinel - This method verifies whether the sentinel for the 284 /// list has been created and lazily makes it if not. 285 void CreateLazySentinel() const { 286 if (Head != 0) return; 287 Head = Traits::createSentinel(); 288 this->setNext(Head, 0); 289 setTail(Head); 290 } 291 292 static bool op_less(NodeTy &L, NodeTy &R) { return L < R; } 293 static bool op_equal(NodeTy &L, NodeTy &R) { return L == R; } 294 295 // No fundamental reason why iplist can't by copyable, but the default 296 // copy/copy-assign won't do. 297 iplist(const iplist &); // do not implement 298 void operator=(const iplist &); // do not implement 299 300public: 301 typedef NodeTy *pointer; 302 typedef const NodeTy *const_pointer; 303 typedef NodeTy &reference; 304 typedef const NodeTy &const_reference; 305 typedef NodeTy value_type; 306 typedef ilist_iterator<NodeTy> iterator; 307 typedef ilist_iterator<const NodeTy> const_iterator; 308 typedef size_t size_type; 309 typedef ptrdiff_t difference_type; 310 typedef std::reverse_iterator<const_iterator> const_reverse_iterator; 311 typedef std::reverse_iterator<iterator> reverse_iterator; 312 313 iplist() : Head(0) {} 314 ~iplist() { 315 if (!Head) return; 316 clear(); 317 Traits::destroySentinel(getTail()); 318 } 319 320 // Iterator creation methods. 321 iterator begin() { 322 CreateLazySentinel(); 323 return iterator(Head); 324 } 325 const_iterator begin() const { 326 CreateLazySentinel(); 327 return const_iterator(Head); 328 } 329 iterator end() { 330 CreateLazySentinel(); 331 return iterator(getTail()); 332 } 333 const_iterator end() const { 334 CreateLazySentinel(); 335 return const_iterator(getTail()); 336 } 337 338 // reverse iterator creation methods. 339 reverse_iterator rbegin() { return reverse_iterator(end()); } 340 const_reverse_iterator rbegin() const{ return const_reverse_iterator(end()); } 341 reverse_iterator rend() { return reverse_iterator(begin()); } 342 const_reverse_iterator rend() const { return const_reverse_iterator(begin());} 343 344 345 // Miscellaneous inspection routines. 346 size_type max_size() const { return size_type(-1); } 347 bool empty() const { return Head == 0 || Head == getTail(); } 348 349 // Front and back accessor functions... 350 reference front() { 351 assert(!empty() && "Called front() on empty list!"); 352 return *Head; 353 } 354 const_reference front() const { 355 assert(!empty() && "Called front() on empty list!"); 356 return *Head; 357 } 358 reference back() { 359 assert(!empty() && "Called back() on empty list!"); 360 return *this->getPrev(getTail()); 361 } 362 const_reference back() const { 363 assert(!empty() && "Called back() on empty list!"); 364 return *this->getPrev(getTail()); 365 } 366 367 void swap(iplist &RHS) { 368 assert(0 && "Swap does not use list traits callback correctly yet!"); 369 std::swap(Head, RHS.Head); 370 } 371 372 iterator insert(iterator where, NodeTy *New) { 373 NodeTy *CurNode = where.getNodePtrUnchecked(), *PrevNode = this->getPrev(CurNode); 374 this->setNext(New, CurNode); 375 this->setPrev(New, PrevNode); 376 377 if (CurNode != Head) // Is PrevNode off the beginning of the list? 378 this->setNext(PrevNode, New); 379 else 380 Head = New; 381 this->setPrev(CurNode, New); 382 383 this->addNodeToList(New); // Notify traits that we added a node... 384 return New; 385 } 386 387 NodeTy *remove(iterator &IT) { 388 assert(IT != end() && "Cannot remove end of list!"); 389 NodeTy *Node = &*IT; 390 NodeTy *NextNode = this->getNext(Node); 391 NodeTy *PrevNode = this->getPrev(Node); 392 393 if (Node != Head) // Is PrevNode off the beginning of the list? 394 this->setNext(PrevNode, NextNode); 395 else 396 Head = NextNode; 397 this->setPrev(NextNode, PrevNode); 398 IT = NextNode; 399 removeNodeFromList(Node); // Notify traits that we removed a node... 400 401 // Set the next/prev pointers of the current node to null. This isn't 402 // strictly required, but this catches errors where a node is removed from 403 // an ilist (and potentially deleted) with iterators still pointing at it. 404 // When those iterators are incremented or decremented, they will assert on 405 // the null next/prev pointer instead of "usually working". 406 this->setNext(Node, 0); 407 this->setPrev(Node, 0); 408 return Node; 409 } 410 411 NodeTy *remove(const iterator &IT) { 412 iterator MutIt = IT; 413 return remove(MutIt); 414 } 415 416 // erase - remove a node from the controlled sequence... and delete it. 417 iterator erase(iterator where) { 418 deleteNode(remove(where)); 419 return where; 420 } 421 422 423private: 424 // transfer - The heart of the splice function. Move linked list nodes from 425 // [first, last) into position. 426 // 427 void transfer(iterator position, iplist &L2, iterator first, iterator last) { 428 assert(first != last && "Should be checked by callers"); 429 430 if (position != last) { 431 // Note: we have to be careful about the case when we move the first node 432 // in the list. This node is the list sentinel node and we can't move it. 433 NodeTy *ThisSentinel = getTail(); 434 setTail(0); 435 NodeTy *L2Sentinel = L2.getTail(); 436 L2.setTail(0); 437 438 // Remove [first, last) from its old position. 439 NodeTy *First = &*first, *Prev = getPrev(First); 440 NodeTy *Next = last.getNodePtrUnchecked(), *Last = getPrev(Next); 441 if (Prev) 442 this->setNext(Prev, Next); 443 else 444 L2.Head = Next; 445 this->setPrev(Next, Prev); 446 447 // Splice [first, last) into its new position. 448 NodeTy *PosNext = position.getNodePtrUnchecked(); 449 NodeTy *PosPrev = getPrev(PosNext); 450 451 // Fix head of list... 452 if (PosPrev) 453 this->setNext(PosPrev, First); 454 else 455 Head = First; 456 this->setPrev(First, PosPrev); 457 458 // Fix end of list... 459 this->setNext(Last, PosNext); 460 this->setPrev(PosNext, Last); 461 462 transferNodesFromList(L2, First, PosNext); 463 464 // Now that everything is set, restore the pointers to the list sentinels. 465 L2.setTail(L2Sentinel); 466 setTail(ThisSentinel); 467 } 468 } 469 470public: 471 472 //===----------------------------------------------------------------------=== 473 // Functionality derived from other functions defined above... 474 // 475 476 size_type size() const { 477 if (Head == 0) return 0; // Don't require construction of sentinel if empty. 478#if __GNUC__ == 2 479 // GCC 2.95 has a broken std::distance 480 size_type Result = 0; 481 std::distance(begin(), end(), Result); 482 return Result; 483#else 484 return std::distance(begin(), end()); 485#endif 486 } 487 488 iterator erase(iterator first, iterator last) { 489 while (first != last) 490 first = erase(first); 491 return last; 492 } 493 494 void clear() { if (Head) erase(begin(), end()); } 495 496 // Front and back inserters... 497 void push_front(NodeTy *val) { insert(begin(), val); } 498 void push_back(NodeTy *val) { insert(end(), val); } 499 void pop_front() { 500 assert(!empty() && "pop_front() on empty list!"); 501 erase(begin()); 502 } 503 void pop_back() { 504 assert(!empty() && "pop_back() on empty list!"); 505 iterator t = end(); erase(--t); 506 } 507 508 // Special forms of insert... 509 template<class InIt> void insert(iterator where, InIt first, InIt last) { 510 for (; first != last; ++first) insert(where, *first); 511 } 512 513 // Splice members - defined in terms of transfer... 514 void splice(iterator where, iplist &L2) { 515 if (!L2.empty()) 516 transfer(where, L2, L2.begin(), L2.end()); 517 } 518 void splice(iterator where, iplist &L2, iterator first) { 519 iterator last = first; ++last; 520 if (where == first || where == last) return; // No change 521 transfer(where, L2, first, last); 522 } 523 void splice(iterator where, iplist &L2, iterator first, iterator last) { 524 if (first != last) transfer(where, L2, first, last); 525 } 526 527 528 529 //===----------------------------------------------------------------------=== 530 // High-Level Functionality that shouldn't really be here, but is part of list 531 // 532 533 // These two functions are actually called remove/remove_if in list<>, but 534 // they actually do the job of erase, rename them accordingly. 535 // 536 void erase(const NodeTy &val) { 537 for (iterator I = begin(), E = end(); I != E; ) { 538 iterator next = I; ++next; 539 if (*I == val) erase(I); 540 I = next; 541 } 542 } 543 template<class Pr1> void erase_if(Pr1 pred) { 544 for (iterator I = begin(), E = end(); I != E; ) { 545 iterator next = I; ++next; 546 if (pred(*I)) erase(I); 547 I = next; 548 } 549 } 550 551 template<class Pr2> void unique(Pr2 pred) { 552 if (empty()) return; 553 for (iterator I = begin(), E = end(), Next = begin(); ++Next != E;) { 554 if (pred(*I)) 555 erase(Next); 556 else 557 I = Next; 558 Next = I; 559 } 560 } 561 void unique() { unique(op_equal); } 562 563 template<class Pr3> void merge(iplist &right, Pr3 pred) { 564 iterator first1 = begin(), last1 = end(); 565 iterator first2 = right.begin(), last2 = right.end(); 566 while (first1 != last1 && first2 != last2) 567 if (pred(*first2, *first1)) { 568 iterator next = first2; 569 transfer(first1, right, first2, ++next); 570 first2 = next; 571 } else { 572 ++first1; 573 } 574 if (first2 != last2) transfer(last1, right, first2, last2); 575 } 576 void merge(iplist &right) { return merge(right, op_less); } 577 578 template<class Pr3> void sort(Pr3 pred); 579 void sort() { sort(op_less); } 580 void reverse(); 581}; 582 583 584template<typename NodeTy> 585struct ilist : public iplist<NodeTy> { 586 typedef typename iplist<NodeTy>::size_type size_type; 587 typedef typename iplist<NodeTy>::iterator iterator; 588 589 ilist() {} 590 ilist(const ilist &right) { 591 insert(this->begin(), right.begin(), right.end()); 592 } 593 explicit ilist(size_type count) { 594 insert(this->begin(), count, NodeTy()); 595 } 596 ilist(size_type count, const NodeTy &val) { 597 insert(this->begin(), count, val); 598 } 599 template<class InIt> ilist(InIt first, InIt last) { 600 insert(this->begin(), first, last); 601 } 602 603 604 // Forwarding functions: A workaround for GCC 2.95 which does not correctly 605 // support 'using' declarations to bring a hidden member into scope. 606 // 607 iterator insert(iterator a, NodeTy *b){ return iplist<NodeTy>::insert(a, b); } 608 void push_front(NodeTy *a) { iplist<NodeTy>::push_front(a); } 609 void push_back(NodeTy *a) { iplist<NodeTy>::push_back(a); } 610 611 612 // Main implementation here - Insert for a node passed by value... 613 iterator insert(iterator where, const NodeTy &val) { 614 return insert(where, createNode(val)); 615 } 616 617 618 // Front and back inserters... 619 void push_front(const NodeTy &val) { insert(this->begin(), val); } 620 void push_back(const NodeTy &val) { insert(this->end(), val); } 621 622 // Special forms of insert... 623 template<class InIt> void insert(iterator where, InIt first, InIt last) { 624 for (; first != last; ++first) insert(where, *first); 625 } 626 void insert(iterator where, size_type count, const NodeTy &val) { 627 for (; count != 0; --count) insert(where, val); 628 } 629 630 // Assign special forms... 631 void assign(size_type count, const NodeTy &val) { 632 iterator I = this->begin(); 633 for (; I != this->end() && count != 0; ++I, --count) 634 *I = val; 635 if (count != 0) 636 insert(this->end(), val, val); 637 else 638 erase(I, this->end()); 639 } 640 template<class InIt> void assign(InIt first1, InIt last1) { 641 iterator first2 = this->begin(), last2 = this->end(); 642 for ( ; first1 != last1 && first2 != last2; ++first1, ++first2) 643 *first1 = *first2; 644 if (first2 == last2) 645 erase(first1, last1); 646 else 647 insert(last1, first2, last2); 648 } 649 650 651 // Resize members... 652 void resize(size_type newsize, NodeTy val) { 653 iterator i = this->begin(); 654 size_type len = 0; 655 for ( ; i != this->end() && len < newsize; ++i, ++len) /* empty*/ ; 656 657 if (len == newsize) 658 erase(i, this->end()); 659 else // i == end() 660 insert(this->end(), newsize - len, val); 661 } 662 void resize(size_type newsize) { resize(newsize, NodeTy()); } 663}; 664 665} // End llvm namespace 666 667namespace std { 668 // Ensure that swap uses the fast list swap... 669 template<class Ty> 670 void swap(llvm::iplist<Ty> &Left, llvm::iplist<Ty> &Right) { 671 Left.swap(Right); 672 } 673} // End 'std' extensions... 674 675#endif // LLVM_ADT_ILIST_H 676