1 //==-- llvm/ADT/ilist.h - Intrusive Linked List Template ---------*- C++ -*-==//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
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
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.
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.
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.
30 // Requirements for a user of this list:
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
36 //===----------------------------------------------------------------------===//
38 #ifndef LLVM_ADT_ILIST_H
39 #define LLVM_ADT_ILIST_H
41 #include "llvm/ADT/iterator.h"
46 template<typename NodeTy, typename Traits> class iplist;
47 template<typename NodeTy> class ilist_iterator;
49 /// ilist_nextprev_traits - A fragment for template traits for intrusive list
50 /// that provides default next/prev implementations for common operations.
52 template<typename NodeTy>
53 struct 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(); }
59 static void setPrev(NodeTy *N, NodeTy *Prev) { N->setPrev(Prev); }
60 static void setNext(NodeTy *N, NodeTy *Next) { N->setNext(Next); }
63 /// ilist_sentinel_traits - A fragment for template traits for intrusive list
64 /// that provides default sentinel implementations for common operations.
66 template<typename NodeTy>
67 struct ilist_sentinel_traits {
68 static NodeTy *createSentinel() { return new NodeTy(); }
69 static void destroySentinel(NodeTy *N) { delete N; }
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.
76 template<typename NodeTy>
77 struct 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; }
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*/) {}
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...
91 template<typename NodeTy>
92 struct ilist_traits : ilist_default_traits<NodeTy> {};
94 // Const traits are the same as nonconst traits...
96 struct ilist_traits<const Ty> : public ilist_traits<Ty> {};
98 //===----------------------------------------------------------------------===//
99 // ilist_iterator<Node> - Iterator for intrusive list.
101 template<typename NodeTy>
103 : public bidirectional_iterator<NodeTy, ptrdiff_t> {
106 typedef ilist_traits<NodeTy> Traits;
107 typedef bidirectional_iterator<NodeTy, ptrdiff_t> super;
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;
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;
132 ilist_iterator(pointer NP) : NodePtr(NP) {}
133 ilist_iterator(reference NR) : NodePtr(&NR) {}
134 ilist_iterator() : NodePtr(0) {}
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()) {}
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();
151 operator pointer() const {
152 assert(Traits::getNext(NodePtr) != 0 && "Dereferencing end()!");
156 reference operator*() const {
157 assert(Traits::getNext(NodePtr) != 0 && "Dereferencing end()!");
160 pointer operator->() const { return &operator*(); }
162 // Comparison operators
163 bool operator==(const ilist_iterator &RHS) const {
164 return NodePtr == RHS.NodePtr;
166 bool operator!=(const ilist_iterator &RHS) const {
167 return NodePtr != RHS.NodePtr;
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!");
176 ilist_iterator &operator++() { // preincrement - Advance
177 NodePtr = Traits::getNext(NodePtr);
178 assert(NodePtr && "++'d off the end of an ilist!");
181 ilist_iterator operator--(int) { // postdecrement operators...
182 ilist_iterator tmp = *this;
186 ilist_iterator operator++(int) { // postincrement operators...
187 ilist_iterator tmp = *this;
192 // Internal interface, do not use...
193 pointer getNodePtrUnchecked() const { return NodePtr; }
196 // do not implement. this is to catch errors when people try to use
197 // them as random access iterators
199 void operator-(int, ilist_iterator<T>);
201 void operator-(ilist_iterator<T>,int);
204 void operator+(int, ilist_iterator<T>);
206 void operator+(ilist_iterator<T>,int);
208 // operator!=/operator== - Allow mixed comparisons without dereferencing
209 // the iterator, which could very likely be pointing to end().
211 bool operator!=(const T* LHS, const ilist_iterator<const T> &RHS) {
212 return LHS != RHS.getNodePtrUnchecked();
215 bool operator==(const T* LHS, const ilist_iterator<const T> &RHS) {
216 return LHS == RHS.getNodePtrUnchecked();
219 bool operator!=(T* LHS, const ilist_iterator<T> &RHS) {
220 return LHS != RHS.getNodePtrUnchecked();
223 bool operator==(T* LHS, const ilist_iterator<T> &RHS) {
224 return LHS == RHS.getNodePtrUnchecked();
228 // Allow ilist_iterators to convert into pointers to a node automatically when
229 // used by the dyn_cast, cast, isa mechanisms...
231 template<typename From> struct simplify_type;
233 template<typename NodeTy> struct simplify_type<ilist_iterator<NodeTy> > {
234 typedef NodeTy* SimpleType;
236 static SimpleType getSimplifiedValue(const ilist_iterator<NodeTy> &Node) {
240 template<typename NodeTy> struct simplify_type<const ilist_iterator<NodeTy> > {
241 typedef NodeTy* SimpleType;
243 static SimpleType getSimplifiedValue(const ilist_iterator<NodeTy> &Node) {
249 //===----------------------------------------------------------------------===//
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.
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.
271 template<typename NodeTy, typename Traits=ilist_traits<NodeTy> >
272 class iplist : public Traits {
273 mutable NodeTy *Head;
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); }
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);
292 static bool op_less(NodeTy &L, NodeTy &R) { return L < R; }
293 static bool op_equal(NodeTy &L, NodeTy &R) { return L == R; }
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
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;
313 iplist() : Head(0) {}
317 Traits::destroySentinel(getTail());
320 // Iterator creation methods.
322 CreateLazySentinel();
323 return iterator(Head);
325 const_iterator begin() const {
326 CreateLazySentinel();
327 return const_iterator(Head);
330 CreateLazySentinel();
331 return iterator(getTail());
333 const_iterator end() const {
334 CreateLazySentinel();
335 return const_iterator(getTail());
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());}
345 // Miscellaneous inspection routines.
346 size_type max_size() const { return size_type(-1); }
347 bool empty() const { return Head == 0 || Head == getTail(); }
349 // Front and back accessor functions...
351 assert(!empty() && "Called front() on empty list!");
354 const_reference front() const {
355 assert(!empty() && "Called front() on empty list!");
359 assert(!empty() && "Called back() on empty list!");
360 return *this->getPrev(getTail());
362 const_reference back() const {
363 assert(!empty() && "Called back() on empty list!");
364 return *this->getPrev(getTail());
367 void swap(iplist &RHS) {
368 assert(0 && "Swap does not use list traits callback correctly yet!");
369 std::swap(Head, RHS.Head);
372 iterator insert(iterator where, NodeTy *New) {
373 NodeTy *CurNode = where.getNodePtrUnchecked();
374 NodeTy *PrevNode = this->getPrev(CurNode);
375 this->setNext(New, CurNode);
376 this->setPrev(New, PrevNode);
378 if (CurNode != Head) // Is PrevNode off the beginning of the list?
379 this->setNext(PrevNode, New);
382 this->setPrev(CurNode, New);
384 this->addNodeToList(New); // Notify traits that we added a node...
388 iterator insertAfter(iterator where, NodeTy *New) {
390 return insert(begin(), New);
392 return insert(++where, New);
395 NodeTy *remove(iterator &IT) {
396 assert(IT != end() && "Cannot remove end of list!");
398 NodeTy *NextNode = this->getNext(Node);
399 NodeTy *PrevNode = this->getPrev(Node);
401 if (Node != Head) // Is PrevNode off the beginning of the list?
402 this->setNext(PrevNode, NextNode);
405 this->setPrev(NextNode, PrevNode);
407 this->removeNodeFromList(Node); // Notify traits that we removed a node...
409 // Set the next/prev pointers of the current node to null. This isn't
410 // strictly required, but this catches errors where a node is removed from
411 // an ilist (and potentially deleted) with iterators still pointing at it.
412 // When those iterators are incremented or decremented, they will assert on
413 // the null next/prev pointer instead of "usually working".
414 this->setNext(Node, 0);
415 this->setPrev(Node, 0);
419 NodeTy *remove(const iterator &IT) {
421 return remove(MutIt);
424 // erase - remove a node from the controlled sequence... and delete it.
425 iterator erase(iterator where) {
426 this->deleteNode(remove(where));
432 // transfer - The heart of the splice function. Move linked list nodes from
433 // [first, last) into position.
435 void transfer(iterator position, iplist &L2, iterator first, iterator last) {
436 assert(first != last && "Should be checked by callers");
438 if (position != last) {
439 // Note: we have to be careful about the case when we move the first node
440 // in the list. This node is the list sentinel node and we can't move it.
441 NodeTy *ThisSentinel = getTail();
443 NodeTy *L2Sentinel = L2.getTail();
446 // Remove [first, last) from its old position.
447 NodeTy *First = &*first, *Prev = getPrev(First);
448 NodeTy *Next = last.getNodePtrUnchecked(), *Last = getPrev(Next);
450 this->setNext(Prev, Next);
453 this->setPrev(Next, Prev);
455 // Splice [first, last) into its new position.
456 NodeTy *PosNext = position.getNodePtrUnchecked();
457 NodeTy *PosPrev = getPrev(PosNext);
459 // Fix head of list...
461 this->setNext(PosPrev, First);
464 this->setPrev(First, PosPrev);
466 // Fix end of list...
467 this->setNext(Last, PosNext);
468 this->setPrev(PosNext, Last);
470 transferNodesFromList(L2, First, PosNext);
472 // Now that everything is set, restore the pointers to the list sentinels.
473 L2.setTail(L2Sentinel);
474 setTail(ThisSentinel);
480 //===----------------------------------------------------------------------===
481 // Functionality derived from other functions defined above...
484 size_type size() const {
485 if (Head == 0) return 0; // Don't require construction of sentinel if empty.
487 // GCC 2.95 has a broken std::distance
488 size_type Result = 0;
489 std::distance(begin(), end(), Result);
492 return std::distance(begin(), end());
496 iterator erase(iterator first, iterator last) {
497 while (first != last)
498 first = erase(first);
502 void clear() { if (Head) erase(begin(), end()); }
504 // Front and back inserters...
505 void push_front(NodeTy *val) { insert(begin(), val); }
506 void push_back(NodeTy *val) { insert(end(), val); }
508 assert(!empty() && "pop_front() on empty list!");
512 assert(!empty() && "pop_back() on empty list!");
513 iterator t = end(); erase(--t);
516 // Special forms of insert...
517 template<class InIt> void insert(iterator where, InIt first, InIt last) {
518 for (; first != last; ++first) insert(where, *first);
521 // Splice members - defined in terms of transfer...
522 void splice(iterator where, iplist &L2) {
524 transfer(where, L2, L2.begin(), L2.end());
526 void splice(iterator where, iplist &L2, iterator first) {
527 iterator last = first; ++last;
528 if (where == first || where == last) return; // No change
529 transfer(where, L2, first, last);
531 void splice(iterator where, iplist &L2, iterator first, iterator last) {
532 if (first != last) transfer(where, L2, first, last);
537 //===----------------------------------------------------------------------===
538 // High-Level Functionality that shouldn't really be here, but is part of list
541 // These two functions are actually called remove/remove_if in list<>, but
542 // they actually do the job of erase, rename them accordingly.
544 void erase(const NodeTy &val) {
545 for (iterator I = begin(), E = end(); I != E; ) {
546 iterator next = I; ++next;
547 if (*I == val) erase(I);
551 template<class Pr1> void erase_if(Pr1 pred) {
552 for (iterator I = begin(), E = end(); I != E; ) {
553 iterator next = I; ++next;
554 if (pred(*I)) erase(I);
559 template<class Pr2> void unique(Pr2 pred) {
561 for (iterator I = begin(), E = end(), Next = begin(); ++Next != E;) {
569 void unique() { unique(op_equal); }
571 template<class Pr3> void merge(iplist &right, Pr3 pred) {
572 iterator first1 = begin(), last1 = end();
573 iterator first2 = right.begin(), last2 = right.end();
574 while (first1 != last1 && first2 != last2)
575 if (pred(*first2, *first1)) {
576 iterator next = first2;
577 transfer(first1, right, first2, ++next);
582 if (first2 != last2) transfer(last1, right, first2, last2);
584 void merge(iplist &right) { return merge(right, op_less); }
586 template<class Pr3> void sort(Pr3 pred);
587 void sort() { sort(op_less); }
592 template<typename NodeTy>
593 struct ilist : public iplist<NodeTy> {
594 typedef typename iplist<NodeTy>::size_type size_type;
595 typedef typename iplist<NodeTy>::iterator iterator;
598 ilist(const ilist &right) {
599 insert(this->begin(), right.begin(), right.end());
601 explicit ilist(size_type count) {
602 insert(this->begin(), count, NodeTy());
604 ilist(size_type count, const NodeTy &val) {
605 insert(this->begin(), count, val);
607 template<class InIt> ilist(InIt first, InIt last) {
608 insert(this->begin(), first, last);
612 // Forwarding functions: A workaround for GCC 2.95 which does not correctly
613 // support 'using' declarations to bring a hidden member into scope.
615 iterator insert(iterator a, NodeTy *b){ return iplist<NodeTy>::insert(a, b); }
616 void push_front(NodeTy *a) { iplist<NodeTy>::push_front(a); }
617 void push_back(NodeTy *a) { iplist<NodeTy>::push_back(a); }
620 // Main implementation here - Insert for a node passed by value...
621 iterator insert(iterator where, const NodeTy &val) {
622 return insert(where, createNode(val));
626 // Front and back inserters...
627 void push_front(const NodeTy &val) { insert(this->begin(), val); }
628 void push_back(const NodeTy &val) { insert(this->end(), val); }
630 // Special forms of insert...
631 template<class InIt> void insert(iterator where, InIt first, InIt last) {
632 for (; first != last; ++first) insert(where, *first);
634 void insert(iterator where, size_type count, const NodeTy &val) {
635 for (; count != 0; --count) insert(where, val);
638 // Assign special forms...
639 void assign(size_type count, const NodeTy &val) {
640 iterator I = this->begin();
641 for (; I != this->end() && count != 0; ++I, --count)
644 insert(this->end(), val, val);
646 erase(I, this->end());
648 template<class InIt> void assign(InIt first1, InIt last1) {
649 iterator first2 = this->begin(), last2 = this->end();
650 for ( ; first1 != last1 && first2 != last2; ++first1, ++first2)
653 erase(first1, last1);
655 insert(last1, first2, last2);
660 void resize(size_type newsize, NodeTy val) {
661 iterator i = this->begin();
663 for ( ; i != this->end() && len < newsize; ++i, ++len) /* empty*/ ;
666 erase(i, this->end());
668 insert(this->end(), newsize - len, val);
670 void resize(size_type newsize) { resize(newsize, NodeTy()); }
673 } // End llvm namespace
676 // Ensure that swap uses the fast list swap...
678 void swap(llvm::iplist<Ty> &Left, llvm::iplist<Ty> &Right) {
681 } // End 'std' extensions...
683 #endif // LLVM_ADT_ILIST_H