/*******************************************************************************
* Copyright (c) 2015 Bruno Medeiros and other Contributors.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* Bruno Medeiros - initial API and implementation
*******************************************************************************/
package melnorme.lang.utils.parse;
import static melnorme.utilbox.core.Assert.AssertNamespace.assertTrue;
public abstract class OffsetBasedCharacterReader<EXC extends Exception> extends BasicCharSource<EXC> {
protected int readPosition = 0;
public OffsetBasedCharacterReader() {
super();
}
public int getReadPosition() {
return readPosition;
}
public int getConsumedCount() {
return readPosition;
}
protected void invariant() {
assertTrue(readPosition >= 0);
}
@Override
protected void consume_next_invariant(int next) {
// allow consume at EOS
}
@Override
protected void doConsume() throws EXC {
readPosition++;
invariant();
}
/**
* Same as {@link IBasicCharSource#consumeAmount(int)} but one is allowed to consume beyond EOS.
*/
@Override
public void consumeAmount(int count) throws EXC {
readPosition += count;
invariant();
}
@Override
public void unread() throws EXC {
readPosition--;
invariant();
doUnread();
}
protected abstract void doUnread() throws EXC;
public void reset() throws EXC {
readPosition = 0;
}
}