/*
- * $Id: splay.h,v 1.7 1998/09/23 17:20:05 wessels Exp $
+ * Copyright (C) 1996-2014 The Squid Software Foundation and contributors
+ *
+ * Squid software is distributed under GPLv2+ license and includes
+ * contributions from numerous individuals and organizations.
+ * Please see the COPYING and CONTRIBUTORS files for details.
*/
+#ifndef SQUID_SPLAY_H
+#define SQUID_SPLAY_H
-typedef struct _splay_node {
- void *data;
- struct _splay_node *left;
- struct _splay_node *right;
-} splayNode;
+#include "fatal.h"
+#include <stack>
-typedef int SPLAYCMP(const void *, splayNode *);
-typedef void SPLAYWALKEE(void *, void *);
-typedef void SPLAYFREE(void *);
+// private class of Splay. Do not use directly
+template <class V>
+class SplayNode
+{
+public:
+ typedef V Value;
+ typedef int SPLAYCMP(Value const &a, Value const &b);
+ typedef void SPLAYFREE(Value &);
+ typedef void SPLAYWALKEE(Value const & nodedata, void *state);
+ static void DefaultFree (Value &aValue) {delete aValue;}
-extern int splayLastResult;
+ SplayNode<V> (Value const &);
+ Value data;
+ mutable SplayNode<V> *left;
+ mutable SplayNode<V> *right;
+ void destroy(SPLAYFREE * = DefaultFree);
+ void walk(SPLAYWALKEE *, void *callerState);
+ SplayNode<V> const * start() const;
+ SplayNode<V> const * finish() const;
+
+ SplayNode<V> * remove(const Value data, SPLAYCMP * compare);
+
+ SplayNode<V> * insert(Value data, SPLAYCMP * compare);
+
+ /// look in the splay for data for where compare(data,candidate) == true.
+ /// return NULL if not found, a pointer to the sought data if found.
+ template <class FindValue> SplayNode<V> * splay(const FindValue &data, int( * compare)(FindValue const &a, Value const &b)) const;
+
+ /// recursively visit left nodes, this node, and then right nodes
+ template <class Visitor> void visit(Visitor &v) const;
+};
+
+typedef SplayNode<void *> splayNode;
+
+template <class V>
+class SplayConstIterator;
+
+template <class V>
+class SplayIterator;
+
+template <class V>
+class Splay
+{
+public:
+ typedef V Value;
+ typedef int SPLAYCMP(Value const &a, Value const &b);
+ typedef void SPLAYFREE(Value &);
+ typedef SplayIterator<V> iterator;
+ typedef const SplayConstIterator<V> const_iterator;
+ Splay():head(NULL), elements (0) {}
+
+ template <class FindValue> Value const *find (FindValue const &, int( * compare)(FindValue const &a, Value const &b)) const;
+
+ void insert(Value const &, SPLAYCMP *compare);
+
+ void remove(Value const &, SPLAYCMP *compare);
+
+ void destroy(SPLAYFREE * = SplayNode<V>::DefaultFree);
+
+ SplayNode<V> const * start() const;
+
+ SplayNode<V> const * finish() const;
+
+ size_t size() const;
+
+ bool empty() const { return size() == 0; }
+
+ const_iterator begin() const;
+
+ const_iterator end() const;
+
+ /// recursively visit all nodes, in left-to-right order
+ template <class Visitor> void visit(Visitor &v) const;
+
+private:
+ mutable SplayNode<V> * head;
+ size_t elements;
+};
+
+SQUIDCEXTERN int splayLastResult;
+
+template<class V>
+SplayNode<V>::SplayNode (Value const &someData) : data(someData), left(NULL), right (NULL) {}
+
+template<class V>
+void
+SplayNode<V>::walk(SPLAYWALKEE * walkee, void *state)
+{
+ if (left)
+ left->walk(walkee, state);
+
+ walkee(data, state);
+
+ if (right)
+ right->walk(walkee, state);
+}
+
+template<class V>
+SplayNode<V> const *
+SplayNode<V>::start() const
+{
+ if (left)
+ return left->start();
+
+ return this;
+}
+
+template<class V>
+SplayNode<V> const *
+SplayNode<V>::finish() const
+{
+ if (right)
+ return right->finish();
+
+ return this;
+}
+
+template<class V>
+void
+SplayNode<V>::destroy(SPLAYFREE * free_func)
+{
+ if (left)
+ left->destroy(free_func);
+
+ if (right)
+ right->destroy(free_func);
+
+ free_func(data);
+
+ delete this;
+}
+
+template<class V>
+SplayNode<V> *
+SplayNode<V>::remove(Value const dataToRemove, SPLAYCMP * compare)
+{
+ SplayNode<V> *result = splay(dataToRemove, compare);
+
+ if (splayLastResult == 0) { /* found it */
+ SplayNode<V> *newTop;
+
+ if (result->left == NULL) {
+ newTop = result->right;
+ } else {
+ newTop = result->left->splay(dataToRemove, compare);
+ /* temporary */
+ newTop->right = result->right;
+ result->right = NULL;
+ }
+
+ delete result;
+ return newTop;
+ }
+
+ return result; /* It wasn't there */
+}
+
+template<class V>
+SplayNode<V> *
+SplayNode<V>::insert(Value dataToInsert, SPLAYCMP * compare)
+{
+ /* create node to insert */
+ SplayNode<V> *newNode = new SplayNode<V>(dataToInsert);
+ SplayNode<V> *newTop = splay(dataToInsert, compare);
+
+ if (splayLastResult < 0) {
+ newNode->left = newTop->left;
+ newNode->right = newTop;
+ newTop->left = NULL;
+ return newNode;
+ } else if (splayLastResult > 0) {
+ newNode->right = newTop->right;
+ newNode->left = newTop;
+ newTop->right = NULL;
+ return newNode;
+ } else {
+ /* duplicate entry */
+ delete newNode;
+ return newTop;
+ }
+}
+
+template<class V>
+template<class FindValue>
+SplayNode<V> *
+SplayNode<V>::splay(FindValue const &dataToFind, int( * compare)(FindValue const &a, Value const &b)) const
+{
+ Value temp = Value();
+ SplayNode<V> N(temp);
+ SplayNode<V> *l;
+ SplayNode<V> *r;
+ SplayNode<V> *y;
+ N.left = N.right = NULL;
+ l = r = &N;
+
+ SplayNode<V> *top = const_cast<SplayNode<V> *>(this);
+
+ for (;;) {
+ splayLastResult = compare(dataToFind, top->data);
+
+ if (splayLastResult < 0) {
+ if (top->left == NULL)
+ break;
+
+ if ((splayLastResult = compare(dataToFind, top->left->data)) < 0) {
+ y = top->left; /* rotate right */
+ top->left = y->right;
+ y->right = top;
+ top = y;
+
+ if (top->left == NULL)
+ break;
+ }
+
+ r->left = top; /* link right */
+ r = top;
+ top = top->left;
+ } else if (splayLastResult > 0) {
+ if (top->right == NULL)
+ break;
+
+ if ((splayLastResult = compare(dataToFind, top->right->data)) > 0) {
+ y = top->right; /* rotate left */
+ top->right = y->left;
+ y->left = top;
+ top = y;
+
+ if (top->right == NULL)
+ break;
+ }
+
+ l->right = top; /* link left */
+ l = top;
+ top = top->right;
+ } else {
+ break;
+ }
+ }
+
+ l->right = top->left; /* assemble */
+ r->left = top->right;
+ top->left = N.right;
+ top->right = N.left;
+ return top;
+}
+
+template <class V>
+template <class Visitor>
+void
+SplayNode<V>::visit(Visitor &visitor) const
+{
+ if (left)
+ left->visit(visitor);
+ visitor(data);
+ if (right)
+ right->visit(visitor);
+}
+
+template <class V>
+template <class Visitor>
+void
+Splay<V>::visit(Visitor &visitor) const
+{
+ if (head)
+ head->visit(visitor);
+}
+
+template <class V>
+template <class FindValue>
+typename Splay<V>::Value const *
+Splay<V>::find (FindValue const &value, int( * compare)(FindValue const &a, Value const &b)) const
+{
+ if (head == NULL)
+ return NULL;
+
+ head = head->splay(value, compare);
+
+ if (splayLastResult != 0)
+ return NULL;
+
+ return &head->data;
+}
+
+template <class V>
+void
+Splay<V>::insert(Value const &value, SPLAYCMP *compare)
+{
+ assert (find (value, compare) == NULL);
+ if (head == NULL)
+ head = new SplayNode<V>(value);
+ else
+ head = head->insert(value, compare);
+ ++elements;
+}
+
+template <class V>
+void
+Splay<V>::remove(Value const &value, SPLAYCMP *compare)
+{
+ assert (find (value, compare));
+
+ head = head->remove(value, compare);
+
+ --elements;
+}
+
+template <class V>
+SplayNode<V> const *
+Splay<V>:: start() const
+{
+ if (head)
+ return head->start();
+
+ return NULL;
+}
+
+template <class V>
+SplayNode<V> const *
+Splay<V>:: finish() const
+{
+ if (head)
+ return head->finish();
+
+ return NULL;
+}
+
+template <class V>
+void
+Splay<V>:: destroy(SPLAYFREE *free_func)
+{
+ if (head)
+ head->destroy(free_func);
+
+ head = NULL;
+
+ elements = 0;
+}
+
+template <class V>
+size_t
+Splay<V>::size() const
+{
+ return elements;
+}
+
+template <class V>
+const SplayConstIterator<V>
+Splay<V>::begin() const
+{
+ return const_iterator(head);
+}
+
+template <class V>
+const SplayConstIterator<V>
+Splay<V>::end() const
+{
+ return const_iterator(NULL);
+}
+
+// XXX: This does not seem to iterate the whole thing in some cases.
+template <class V>
+class SplayConstIterator
+{
+
+public:
+ typedef const V value_type;
+ SplayConstIterator (SplayNode<V> *aNode);
+ bool operator == (SplayConstIterator const &right) const;
+ SplayConstIterator operator ++ (int dummy);
+ SplayConstIterator &operator ++ ();
+ V const & operator * () const;
+
+private:
+ void advance();
+ void addLeftPath(SplayNode<V> *aNode);
+ void init(SplayNode<V> *);
+ std::stack<SplayNode<V> *> toVisit;
+};
+
+template <class V>
+SplayConstIterator<V>::SplayConstIterator (SplayNode<V> *aNode)
+{
+ init(aNode);
+}
+
+template <class V>
+bool
+SplayConstIterator<V>::operator == (SplayConstIterator const &right) const
+{
+ if (toVisit.empty() && right.toVisit.empty())
+ return true;
+ if (!toVisit.empty() && !right.toVisit.empty())
+ return toVisit.top() == right.toVisit.top();
+ // only one of the two is empty
+ return false;
+}
+
+template <class V>
+SplayConstIterator<V> &
+SplayConstIterator<V>::operator ++ ()
+{
+ advance();
+ return *this;
+}
+
+template <class V>
+SplayConstIterator<V>
+SplayConstIterator<V>::operator ++ (int dummy)
+{
+ SplayConstIterator<V> result = *this;
+ advance();
+ return result;
+}
+
+/* advance is simple enough:
+* if the stack is empty, we're done.
+* otherwise, pop the last visited node
+* then, pop the next node to visit
+* if that has a right child, add it and it's
+* left-to-end path.
+* then add the node back.
+*/
+template <class V>
+void
+SplayConstIterator<V>::advance()
+{
+ if (toVisit.empty())
+ return;
+
+ toVisit.pop();
+
+ if (toVisit.empty())
+ return;
+
+ // not empty
+ SplayNode<V> *currentNode = toVisit.top();
+ toVisit.pop();
+
+ addLeftPath(currentNode->right);
+
+ toVisit.push(currentNode);
+}
+
+template <class V>
+void
+SplayConstIterator<V>::addLeftPath(SplayNode<V> *aNode)
+{
+ if (aNode == NULL)
+ return;
+
+ do {
+ toVisit.push(aNode);
+ aNode = aNode->left;
+ } while (aNode != NULL);
+}
+
+template <class V>
+void
+SplayConstIterator<V>::init(SplayNode<V> *head)
+{
+ addLeftPath(head);
+}
+
+template <class V>
+V const &
+SplayConstIterator<V>::operator * () const
+{
+ /* can't dereference when past the end */
+
+ if (toVisit.size() == 0)
+ fatal ("Attempt to dereference SplayConstIterator past-the-end\n");
+
+ return toVisit.top()->data;
+}
+
+#endif /* SQUID_SPLAY_H */
-extern splayNode *splay_insert(void *, splayNode *, SPLAYCMP *);
-extern splayNode *splay_splay(const void *, splayNode *, SPLAYCMP *);
-extern void splay_destroy(splayNode *, SPLAYFREE *);
-extern void splay_walk(splayNode *, SPLAYWALKEE *, void *);
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