/*
* FindBugs - Find Bugs in Java programs
* Copyright (C) 2006, University of Maryland
*
* 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
*/
package edu.umd.cs.findbugs.ba;
import java.util.HashMap;
import java.util.Iterator;
/**
* Compute a compact numbering of Locations in a CFG.
* This is useful for analyses that want to use a BitSet to
* keep track of Locations.
*
* @author David Hovemeyer
*/
public class CompactLocationNumbering {
private HashMap<Location, Integer> locationToNumberMap;
private HashMap<Integer, Location> numberToLocationMap;
/**
* Constructor.
*
* @param cfg the CFG containing the Locations to number
*/
public CompactLocationNumbering(CFG cfg) {
this.locationToNumberMap = new HashMap<Location, Integer>();
this.numberToLocationMap = new HashMap<Integer, Location>();
build(cfg);
}
/**
* Get the size of the numbering,
* which is the maximum number assigned plus one.
*
* @return the maximum number assigned plus one
*/
public int getSize() {
return locationToNumberMap.size();
}
/**
* Get the number of given Location,
* which will be a non-negative integer
* in the range 0..getSize() - 1.
*
* @param location
* @return the number of the location
*/
public int getNumber(Location location) {
return locationToNumberMap.get(location).intValue();
}
/**
* Get the Location given its number.
*
* @param number the number
* @return Location corresponding to that number
*/
public Location getLocation(int number) {
return numberToLocationMap.get(number);
}
private void build(CFG cfg) {
int count = 0;
for (Iterator<Location> i = cfg.locationIterator(); i.hasNext(); ) {
Integer number = count++;
Location location = i.next();
locationToNumberMap.put(location, number);
numberToLocationMap.put(number, location);
}
}
}
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