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engines/crab/PriorityQueue.h

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+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+/*
+ * This code is based on the CRAB engine
+ *
+ * Copyright (c) Arvind Raja Yadav
+ *
+ * Licensed under MIT
+ *
+ */
+
+#ifndef CRAB_PRIORITYQUEUE_H
+#define CRAB_PRIORITYQUEUE_H
+
+
+namespace Crab {
+
+//! \brief The open heap used by all cost-based search algorithms.
+//!
+//! This class template is basically a thin wrapper on top of both the <code>std::deque</code>
+//! class template and the <a href="http://www.sgi.com/tech/stl/">STL</a> heap operations.
+template<typename Node>
+class PriorityQueue {
+	Common::Array<Node *> _open;
+	bool (*compare)(Node const *, Node const *);
+
+public:
+	//! \brief Constructs a new <code>%PriorityQueue</code> that heap-sorts nodes
+	//! using the specified comparator.
+	explicit PriorityQueue(bool (*)(Node const *, Node const *));
+
+	//! \brief Returns <code>true</code> if the heap contains no nodes,
+	//! <code>false</code> otherwise.
+	bool empty() const;
+
+	//! \brief Removes all nodes from the heap.
+	//!
+	//! \post
+	//!   - <code>empty()</code>
+	void clear();
+
+	//! \brief Returns the number of nodes currently in the heap.
+	size_t size() const;
+
+	//! \brief Pushes the specified node onto the heap.
+	//!
+	//! The heap will maintain the ordering of its nodes during this operation.
+	//!
+	//! \post
+	//!   - <code>! empty()</code>
+	void push(Node *node);
+
+	//! \brief Returns the least costly node in the heap.
+	//!
+	//! \pre
+	//!   - <code>! empty()</code>
+	Node *front() const;
+
+	//! \brief Removes the least costly node from the heap.
+	//!
+	//! The heap will maintain the ordering of its nodes during this operation.
+	//!
+	//! \pre
+	//!   - <code>! empty()</code>
+	void pop();
+
+	//! \brief Removes all instances of the specified node from the heap.
+	void remove(Node const *node);
+
+	//! \brief Enumerates all nodes in the heap so far.
+	//!
+	//! \param   sorted  the container to which each node will be added.
+	//!
+	//! \pre
+	//!   - There must be no <code>NULL</code> pointers in the heap.
+	//! \post
+	//!   - All nodes should be sorted by this heap's comparator.
+	void enumerate(Common::Array<Node const *> &sorted) const;
+};
+
+template<typename Node>
+PriorityQueue<Node>::PriorityQueue(bool (*c)(Node const *, Node const *)) : _open(), compare(c) {
+}
+
+template<typename Node>
+bool PriorityQueue<Node>::empty() const {
+	return _open.empty();
+}
+
+template<typename Node>
+void PriorityQueue<Node>::clear() {
+	_open.clear();
+}
+
+template<typename Node>
+size_t PriorityQueue<Node>::size() const {
+	return _open.size();
+}
+
+template<typename Node>
+void PriorityQueue<Node>::push(Node *node) {
+	_open.insert(Common::upperBound(_open.begin(), _open.end(), node, compare), node);
+}
+
+template<typename Node>
+Node *PriorityQueue<Node>::front() const {
+	return _open.back();
+}
+
+template<typename Node>
+void PriorityQueue<Node>::pop() {
+	_open.pop_back();
+}
+
+template<typename Node>
+void PriorityQueue<Node>::remove(Node const *node) {
+	_open.erase(Common::remove(_open.begin(), _open.end(), node), _open.end());
+}
+
+template<typename Node>
+void PriorityQueue<Node>::enumerate(Common::Array<Node const *> &sorted) const {
+	sorted.resize(_open.size());
+	Common::copy(_open.begin(), _open.end(), sorted.begin());
+}
+
+} // End of namespace Crab
+
+#endif // CRAB_PRIORITYQUEUE_H