/* Soot - a J*va Optimization Framework
* Copyright (C) 1997 Clark Verbrugge
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/*
* Modified by the Sable Research Group and others 1997-1999.
* See the 'credits' file distributed with Soot for the complete list of
* contributors. (Soot is distributed at http://www.sable.mcgill.ca/soot)
*/
package soot.coffi;
import java.util.ArrayList;
import java.util.NoSuchElementException;
/** A queue of BasicBlocks.
* @author Clark Verbrugge
* @see BasicBlock
*/
final class BBQ {
private final ArrayList<BasicBlock> q = new ArrayList<BasicBlock>();
/** Adds a block to the end of the queue, but only if its <i>inq</i> flag is false.
* @param b the Basic Block in question.
* @see BasicBlock#inq
*/
public void push(BasicBlock b) {
if (b.inq!=true) { // ensure only in queue once...
b.inq = true;
q.add(b);
}
}
/** Removes the first block in the queue (and resets its <i>inq</i> flag).
* @return BasicBlock which was first.
* @exception java.util.NoSuchElementException if the queue is empty.
* @see BasicBlock#inq
*/
public BasicBlock pull() throws NoSuchElementException {
if(q.size()==0)
throw new
NoSuchElementException("Pull from empty BBQ");
BasicBlock b = (q.get(0));
q.remove(0);
b.inq = false;
return b;
}
/** Answers whether a block is in the queue or not.
* @param BasicBlock in question.
* @return <i>true</i> if it is, <i>false</i> if it ain't.
* @see BasicBlock#inq
*/
public boolean contains(BasicBlock b) { return b.inq; }
/** Answers the size of the queue.
* @return size of the queue.
*/
public int size() { return q.size(); }
/** Answers whether the queue is empty
* @return <i>true</i> if it is, <i>false</i> if it ain't.
*/
public boolean isEmpty() { return q.isEmpty(); }
/** Empties the queue of all blocks (and resets their <i>inq</i> flags). */
public void clear() {
BasicBlock b;
for (BasicBlock basicBlock : q) {
b = (basicBlock);
b.inq = false;
}
q.clear();
}
}