/**

 * Back 2 Browser Bytecode Translator

 * Copyright (C) 2012 Jaroslav Tulach <jaroslav.tulach@apidesign.org>

 *

 * 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, version 2 of the License.

 *

 * 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. Look for COPYING file in the top folder.

 * If not, see http://opensource.org/licenses/GPL-2.0.

 */

package org.apidesign.javap;

/**

 *

 * @author Jaroslav Tulach <jtulach@netbeans.org>

 */

public final class TrapDataIterator {

    private final Hashtable exStart = new Hashtable();

    private final Hashtable exStop = new Hashtable();

    private TrapData[] current = new TrapData[10];

    private int currentCount;

    TrapDataIterator(Vector exceptionTable) {

        for (int i=0 ; i < exceptionTable.size(); i++) {

            final TrapData td = (TrapData)exceptionTable.elementAt(i);

            put(exStart, td.start_pc, td);

            put(exStop, td.end_pc, td);

        }

    }

    private static void put(Hashtable h, short key, TrapData td) {

        Short s = Short.valueOf((short)key);

        Vector v = (Vector) h.get(s);

        if (v == null) {

            v = new Vector(1);

            h.put(s, v);

        }

        v.add(td);

    }

    private boolean processAll(Hashtable h, Short key, boolean add) {

        boolean change = false;

        Vector v = (Vector)h.get(key);

        if (v != null) {

            int s = v.size();

            for (int i = 0; i < s; i++) {

                TrapData td = (TrapData)v.elementAt(i);

                if (add) {

                    add(td);

                    change = true;

                } else {

                    remove(td);

                    change = true;

                }

            }

        }

        return change;

    }

    public boolean advanceTo(int i) {

        Short s = Short.valueOf((short)i);

        boolean ch1 = processAll(exStart, s, true);

        boolean ch2 = processAll(exStop, s, false);

        return ch1 || ch2;

    }

    public boolean useTry() {

        return currentCount > 0;

    }

    public TrapData[] current() {

        TrapData[] copy = new TrapData[currentCount];

        for (int i = 0; i < currentCount; i++) {

            copy[i] = current[i];

        }

        return copy;

    }

    private void add(TrapData e) {

        if (currentCount == current.length) {

            TrapData[] data = new TrapData[currentCount * 2];

            for (int i = 0; i < currentCount; i++) {

                data[i] = current[i];

            }

            current = data;

        }

        current[currentCount++] = e;

    }

    private void remove(TrapData e) {

        if (currentCount == 0) {

            return;

        }

        int from = 0;

        while (from < currentCount) {

            if (e == current[from++]) {

                break;

            }

        }

        while (from < currentCount) {

            current[from - 1] = current[from];

            current[from] = null;

            from++;

        }

        currentCount--;

    }

}