1 //===-- llvm/ADT/ilist - Intrusive Linked List Template ---------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source 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 // provides 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
39 #define LLVM_ADT_ILIST
41 #include "llvm/ADT/iterator"
46 template<typename NodeTy, typename Traits> class iplist;
47 template<typename NodeTy> class ilist_iterator;
49 // Template traits for intrusive list. By specializing this template class, you
50 // can change what next/prev fields are used to store the links...
51 template<typename NodeTy>
53 static NodeTy *getPrev(NodeTy *N) { return N->getPrev(); }
54 static NodeTy *getNext(NodeTy *N) { return N->getNext(); }
55 static const NodeTy *getPrev(const NodeTy *N) { return N->getPrev(); }
56 static const NodeTy *getNext(const NodeTy *N) { return N->getNext(); }
58 static void setPrev(NodeTy *N, NodeTy *Prev) { N->setPrev(Prev); }
59 static void setNext(NodeTy *N, NodeTy *Next) { N->setNext(Next); }
61 static NodeTy *createNode(const NodeTy &V) { return new NodeTy(V); }
63 static NodeTy *createSentinel() { return new NodeTy(); }
64 static void destroySentinel(NodeTy *N) { delete N; }
66 void addNodeToList(NodeTy *NTy) {}
67 void removeNodeFromList(NodeTy *NTy) {}
68 void transferNodesFromList(iplist<NodeTy, ilist_traits> &L2,
69 ilist_iterator<NodeTy> first,
70 ilist_iterator<NodeTy> last) {}
73 // Const traits are the same as nonconst traits...
75 struct ilist_traits<const Ty> : public ilist_traits<Ty> {};
78 //===----------------------------------------------------------------------===//
79 // ilist_iterator<Node> - Iterator for intrusive list.
81 template<typename NodeTy>
83 : public bidirectional_iterator<NodeTy, ptrdiff_t> {
84 typedef ilist_traits<NodeTy> Traits;
85 typedef bidirectional_iterator<NodeTy, ptrdiff_t> super;
88 typedef size_t size_type;
89 typedef typename super::pointer pointer;
90 typedef typename super::reference reference;
95 ilist_iterator(pointer NP) : NodePtr(NP) {}
96 ilist_iterator(reference NR) : NodePtr(&NR) {}
97 ilist_iterator() : NodePtr(0) {}
99 // This is templated so that we can allow constructing a const iterator from
100 // a nonconst iterator...
101 template<class node_ty>
102 ilist_iterator(const ilist_iterator<node_ty> &RHS)
103 : NodePtr(RHS.getNodePtrUnchecked()) {}
105 // This is templated so that we can allow assigning to a const iterator from
106 // a nonconst iterator...
107 template<class node_ty>
108 const ilist_iterator &operator=(const ilist_iterator<node_ty> &RHS) {
109 NodePtr = RHS.getNodePtrUnchecked();
114 operator pointer() const {
115 assert(Traits::getNext(NodePtr) != 0 && "Dereferencing end()!");
119 reference operator*() const {
120 assert(Traits::getNext(NodePtr) != 0 && "Dereferencing end()!");
123 pointer operator->() { return &operator*(); }
124 const pointer operator->() const { return &operator*(); }
126 // Comparison operators
127 bool operator==(const ilist_iterator &RHS) const {
128 return NodePtr == RHS.NodePtr;
130 bool operator!=(const ilist_iterator &RHS) const {
131 return NodePtr != RHS.NodePtr;
134 // Increment and decrement operators...
135 ilist_iterator &operator--() { // predecrement - Back up
136 NodePtr = Traits::getPrev(NodePtr);
137 assert(Traits::getNext(NodePtr) && "--'d off the beginning of an ilist!");
140 ilist_iterator &operator++() { // preincrement - Advance
141 NodePtr = Traits::getNext(NodePtr);
142 assert(NodePtr && "++'d off the end of an ilist!");
145 ilist_iterator operator--(int) { // postdecrement operators...
146 ilist_iterator tmp = *this;
150 ilist_iterator operator++(int) { // postincrement operators...
151 ilist_iterator tmp = *this;
156 // Internal interface, do not use...
157 pointer getNodePtrUnchecked() const { return NodePtr; }
160 // do not implement. this is to catch errors when people try to use
161 // them as random access iterators
163 void operator-(int, ilist_iterator<T>);
165 void operator-(ilist_iterator<T>,int);
168 void operator+(int, ilist_iterator<T>);
170 void operator+(ilist_iterator<T>,int);
172 // operator!=/operator== - Allow mixed comparisons without dereferencing
173 // the iterator, which could very likely be pointing to end().
175 bool operator!=(const T* LHS, const ilist_iterator<const T> &RHS) {
176 return LHS != RHS.getNodePtrUnchecked();
179 bool operator==(const T* LHS, const ilist_iterator<const T> &RHS) {
180 return LHS == RHS.getNodePtrUnchecked();
183 bool operator!=(T* LHS, const ilist_iterator<T> &RHS) {
184 return LHS != RHS.getNodePtrUnchecked();
187 bool operator==(T* LHS, const ilist_iterator<T> &RHS) {
188 return LHS == RHS.getNodePtrUnchecked();
192 // Allow ilist_iterators to convert into pointers to a node automatically when
193 // used by the dyn_cast, cast, isa mechanisms...
195 template<typename From> struct simplify_type;
197 template<typename NodeTy> struct simplify_type<ilist_iterator<NodeTy> > {
198 typedef NodeTy* SimpleType;
200 static SimpleType getSimplifiedValue(const ilist_iterator<NodeTy> &Node) {
204 template<typename NodeTy> struct simplify_type<const ilist_iterator<NodeTy> > {
205 typedef NodeTy* SimpleType;
207 static SimpleType getSimplifiedValue(const ilist_iterator<NodeTy> &Node) {
213 //===----------------------------------------------------------------------===//
215 /// iplist - The subset of list functionality that can safely be used on nodes
216 /// of polymorphic types, i.e. a heterogenous list with a common base class that
217 /// holds the next/prev pointers. The only state of the list itself is a single
218 /// pointer to the head of the list.
220 /// This list can be in one of three interesting states:
221 /// 1. The list may be completely unconstructed. In this case, the head
222 /// pointer is null. When in this form, any query for an iterator (e.g.
223 /// begin() or end()) causes the list to transparently change to state #2.
224 /// 2. The list may be empty, but contain a sentinal for the end iterator. This
225 /// sentinal is created by the Traits::createSentinel method and is a link
226 /// in the list. When the list is empty, the pointer in the iplist points
227 /// to the sentinal. Once the sentinal is constructed, it
228 /// is not destroyed until the list is.
229 /// 3. The list may contain actual objects in it, which are stored as a doubly
230 /// linked list of nodes. One invariant of the list is that the predecessor
231 /// of the first node in the list always points to the last node in the list,
232 /// and the successor pointer for the sentinal (which always stays at the
233 /// end of the list) is always null.
235 template<typename NodeTy, typename Traits=ilist_traits<NodeTy> >
236 class iplist : public Traits {
237 mutable NodeTy *Head;
239 // Use the prev node pointer of 'head' as the tail pointer. This is really a
240 // circularly linked list where we snip the 'next' link from the sentinel node
241 // back to the first node in the list (to preserve assertions about going off
242 // the end of the list).
243 NodeTy *getTail() { return getPrev(Head); }
244 const NodeTy *getTail() const { return getPrev(Head); }
245 void setTail(NodeTy *N) const { setPrev(Head, N); }
247 /// CreateLazySentinal - This method verifies whether the sentinal for the
248 /// list has been created and lazily makes it if not.
249 void CreateLazySentinal() const {
250 if (Head != 0) return;
251 Head = Traits::createSentinel();
256 static bool op_less(NodeTy &L, NodeTy &R) { return L < R; }
257 static bool op_equal(NodeTy &L, NodeTy &R) { return L == R; }
259 typedef NodeTy *pointer;
260 typedef const NodeTy *const_pointer;
261 typedef NodeTy &reference;
262 typedef const NodeTy &const_reference;
263 typedef NodeTy value_type;
264 typedef ilist_iterator<NodeTy> iterator;
265 typedef ilist_iterator<const NodeTy> const_iterator;
266 typedef size_t size_type;
267 typedef ptrdiff_t difference_type;
268 typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
269 typedef std::reverse_iterator<iterator> reverse_iterator;
271 iplist() : Head(0) {}
275 Traits::destroySentinel(getTail());
278 // Iterator creation methods.
280 CreateLazySentinal();
281 return iterator(Head);
283 const_iterator begin() const {
284 CreateLazySentinal();
285 return const_iterator(Head);
288 CreateLazySentinal();
289 return iterator(getTail());
291 const_iterator end() const {
292 CreateLazySentinal();
293 return const_iterator(getTail());
296 // reverse iterator creation methods.
297 reverse_iterator rbegin() { return reverse_iterator(end()); }
298 const_reverse_iterator rbegin() const{ return const_reverse_iterator(end()); }
299 reverse_iterator rend() { return reverse_iterator(begin()); }
300 const_reverse_iterator rend() const { return const_reverse_iterator(begin());}
303 // Miscellaneous inspection routines.
304 size_type max_size() const { return size_type(-1); }
305 bool empty() const { return Head == 0 || Head == getTail(); }
307 // Front and back accessor functions...
309 assert(!empty() && "Called front() on empty list!");
312 const_reference front() const {
313 assert(!empty() && "Called front() on empty list!");
317 assert(!empty() && "Called back() on empty list!");
318 return *getPrev(getTail());
320 const_reference back() const {
321 assert(!empty() && "Called back() on empty list!");
322 return *getPrev(getTail());
325 void swap(iplist &RHS) {
326 abort(); // Swap does not use list traits callback correctly yet!
327 std::swap(Head, RHS.Head);
330 iterator insert(iterator where, NodeTy *New) {
331 NodeTy *CurNode = where.getNodePtrUnchecked(), *PrevNode = getPrev(CurNode);
332 setNext(New, CurNode);
333 setPrev(New, PrevNode);
335 if (CurNode != Head) // Is PrevNode off the beginning of the list?
336 setNext(PrevNode, New);
339 setPrev(CurNode, New);
341 addNodeToList(New); // Notify traits that we added a node...
345 NodeTy *remove(iterator &IT) {
346 assert(IT != end() && "Cannot remove end of list!");
348 NodeTy *NextNode = getNext(Node);
349 NodeTy *PrevNode = getPrev(Node);
351 if (Node != Head) // Is PrevNode off the beginning of the list?
352 setNext(PrevNode, NextNode);
355 setPrev(NextNode, PrevNode);
357 removeNodeFromList(Node); // Notify traits that we removed a node...
361 NodeTy *remove(const iterator &IT) {
363 return remove(MutIt);
366 // erase - remove a node from the controlled sequence... and delete it.
367 iterator erase(iterator where) {
368 delete remove(where);
374 // transfer - The heart of the splice function. Move linked list nodes from
375 // [first, last) into position.
377 void transfer(iterator position, iplist &L2, iterator first, iterator last) {
378 assert(first != last && "Should be checked by callers");
380 if (position != last) {
381 // Note: we have to be careful about the case when we move the first node
382 // in the list. This node is the list sentinel node and we can't move it.
383 NodeTy *ThisSentinel = getTail();
385 NodeTy *L2Sentinel = L2.getTail();
388 // Remove [first, last) from its old position.
389 NodeTy *First = &*first, *Prev = getPrev(First);
390 NodeTy *Next = last.getNodePtrUnchecked(), *Last = getPrev(Next);
397 // Splice [first, last) into its new position.
398 NodeTy *PosNext = position.getNodePtrUnchecked();
399 NodeTy *PosPrev = getPrev(PosNext);
401 // Fix head of list...
403 setNext(PosPrev, First);
406 setPrev(First, PosPrev);
408 // Fix end of list...
409 setNext(Last, PosNext);
410 setPrev(PosNext, Last);
412 transferNodesFromList(L2, First, PosNext);
414 // Now that everything is set, restore the pointers to the list sentinals.
415 L2.setTail(L2Sentinel);
416 setTail(ThisSentinel);
422 //===----------------------------------------------------------------------===
423 // Functionality derived from other functions defined above...
426 size_type size() const {
427 if (Head == 0) return 0; // Don't require construction of sentinal if empty.
429 // GCC 2.95 has a broken std::distance
430 size_type Result = 0;
431 std::distance(begin(), end(), Result);
434 return std::distance(begin(), end());
438 iterator erase(iterator first, iterator last) {
439 while (first != last)
440 first = erase(first);
444 void clear() { if (Head) erase(begin(), end()); }
446 // Front and back inserters...
447 void push_front(NodeTy *val) { insert(begin(), val); }
448 void push_back(NodeTy *val) { insert(end(), val); }
450 assert(!empty() && "pop_front() on empty list!");
454 assert(!empty() && "pop_back() on empty list!");
455 iterator t = end(); erase(--t);
458 // Special forms of insert...
459 template<class InIt> void insert(iterator where, InIt first, InIt last) {
460 for (; first != last; ++first) insert(where, *first);
463 // Splice members - defined in terms of transfer...
464 void splice(iterator where, iplist &L2) {
466 transfer(where, L2, L2.begin(), L2.end());
468 void splice(iterator where, iplist &L2, iterator first) {
469 iterator last = first; ++last;
470 if (where == first || where == last) return; // No change
471 transfer(where, L2, first, last);
473 void splice(iterator where, iplist &L2, iterator first, iterator last) {
474 if (first != last) transfer(where, L2, first, last);
479 //===----------------------------------------------------------------------===
480 // High-Level Functionality that shouldn't really be here, but is part of list
483 // These two functions are actually called remove/remove_if in list<>, but
484 // they actually do the job of erase, rename them accordingly.
486 void erase(const NodeTy &val) {
487 for (iterator I = begin(), E = end(); I != E; ) {
488 iterator next = I; ++next;
489 if (*I == val) erase(I);
493 template<class Pr1> void erase_if(Pr1 pred) {
494 for (iterator I = begin(), E = end(); I != E; ) {
495 iterator next = I; ++next;
496 if (pred(*I)) erase(I);
501 template<class Pr2> void unique(Pr2 pred) {
503 for (iterator I = begin(), E = end(), Next = begin(); ++Next != E;) {
511 void unique() { unique(op_equal); }
513 template<class Pr3> void merge(iplist &right, Pr3 pred) {
514 iterator first1 = begin(), last1 = end();
515 iterator first2 = right.begin(), last2 = right.end();
516 while (first1 != last1 && first2 != last2)
517 if (pred(*first2, *first1)) {
518 iterator next = first2;
519 transfer(first1, right, first2, ++next);
524 if (first2 != last2) transfer(last1, right, first2, last2);
526 void merge(iplist &right) { return merge(right, op_less); }
528 template<class Pr3> void sort(Pr3 pred);
529 void sort() { sort(op_less); }
534 template<typename NodeTy>
535 struct ilist : public iplist<NodeTy> {
536 typedef typename iplist<NodeTy>::size_type size_type;
537 typedef typename iplist<NodeTy>::iterator iterator;
540 ilist(const ilist &right) {
541 insert(this->begin(), right.begin(), right.end());
543 explicit ilist(size_type count) {
544 insert(this->begin(), count, NodeTy());
546 ilist(size_type count, const NodeTy &val) {
547 insert(this->begin(), count, val);
549 template<class InIt> ilist(InIt first, InIt last) {
550 insert(this->begin(), first, last);
554 // Forwarding functions: A workaround for GCC 2.95 which does not correctly
555 // support 'using' declarations to bring a hidden member into scope.
557 iterator insert(iterator a, NodeTy *b){ return iplist<NodeTy>::insert(a, b); }
558 void push_front(NodeTy *a) { iplist<NodeTy>::push_front(a); }
559 void push_back(NodeTy *a) { iplist<NodeTy>::push_back(a); }
562 // Main implementation here - Insert for a node passed by value...
563 iterator insert(iterator where, const NodeTy &val) {
564 return insert(where, createNode(val));
568 // Front and back inserters...
569 void push_front(const NodeTy &val) { insert(this->begin(), val); }
570 void push_back(const NodeTy &val) { insert(this->end(), val); }
572 // Special forms of insert...
573 template<class InIt> void insert(iterator where, InIt first, InIt last) {
574 for (; first != last; ++first) insert(where, *first);
576 void insert(iterator where, size_type count, const NodeTy &val) {
577 for (; count != 0; --count) insert(where, val);
580 // Assign special forms...
581 void assign(size_type count, const NodeTy &val) {
582 iterator I = this->begin();
583 for (; I != this->end() && count != 0; ++I, --count)
586 insert(this->end(), val, val);
588 erase(I, this->end());
590 template<class InIt> void assign(InIt first1, InIt last1) {
591 iterator first2 = this->begin(), last2 = this->end();
592 for ( ; first1 != last1 && first2 != last2; ++first1, ++first2)
595 erase(first1, last1);
597 insert(last1, first2, last2);
602 void resize(size_type newsize, NodeTy val) {
603 iterator i = this->begin();
605 for ( ; i != this->end() && len < newsize; ++i, ++len) /* empty*/ ;
608 erase(i, this->end());
610 insert(this->end(), newsize - len, val);
612 void resize(size_type newsize) { resize(newsize, NodeTy()); }
615 } // End llvm namespace
618 // Ensure that swap uses the fast list swap...
620 void swap(llvm::iplist<Ty> &Left, llvm::iplist<Ty> &Right) {
623 } // End 'std' extensions...