/*[INCLUDE-IF Sidecar18-SE]*/
/*
 * Copyright IBM Corp. and others 2007
 *
 * This program and the accompanying materials are made available under
 * the terms of the Eclipse Public License 2.0 which accompanies this
 * distribution and is available at https://www.eclipse.org/legal/epl-2.0/
 * or the Apache License, Version 2.0 which accompanies this distribution and
 * is available at https://www.apache.org/licenses/LICENSE-2.0.
 *
 * This Source Code may also be made available under the following
 * Secondary Licenses when the conditions for such availability set
 * forth in the Eclipse Public License, v. 2.0 are satisfied: GNU
 * General Public License, version 2 with the GNU Classpath
 * Exception [1] and GNU General Public License, version 2 with the
 * OpenJDK Assembly Exception [2].
 *
 * [1] https://www.gnu.org/software/classpath/license.html
 * [2] https://openjdk.org/legal/assembly-exception.html
 *
 * SPDX-License-Identifier: EPL-2.0 OR Apache-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0 OR GPL-2.0-only WITH OpenJDK-assembly-exception-1.0
 */
package com.ibm.dtfj.javacore.parser.framework.input;

import java.io.IOException;

/**
 * Input buffer that computes character offset from disk.
 *
 */
public abstract class OffsetBasedJavaCoreInputBuffer  implements IInputBuffer{

	protected int fOffset;
	private boolean fStreamEnd;

	protected StringBuffer fBuffer;
	protected static final int DEFAULT_LENGTH = 10;
	protected static final int START_OFFSET = 1;

	public OffsetBasedJavaCoreInputBuffer() {
		fBuffer = new StringBuffer();
		fStreamEnd = false;
		fOffset = 1;
	}

	protected void markStreamEnd(boolean mark) {
		fStreamEnd = mark;
	}

	protected boolean isStreamEnd() {
		return fStreamEnd;
	}

	/**
	 * @see com.ibm.dtfj.javacore.parser.framework.input.IInputBuffer#endReached()
	 *
	 * @return determines if everything has been consumed from the reader stream.
	 */
	public boolean endReached() {
		return fStreamEnd && fBuffer.length() == 0;
	}

	/**
	 *
	 * @see com.ibm.dtfj.javacore.parser.framework.input.IInputBuffer#length()
	 *
	 * @return buffer length
	 */
	public int length() {
		return fBuffer.length();
	}

	/**
	 *
	 * @see com.ibm.dtfj.javacore.parser.framework.input.IInputBuffer#charAt(int)
	 *
	 * @param buffer index where character is located
	 * @return character at specified index
	 */
	public char charAt(int i) {
		return fBuffer.charAt(i);
	}

	/**
	 *
	 * @param length to add to current offset
	 */
	protected void updateOffset(int length) {
		fOffset += length;
	}

	/**
	 * Closes the java.io.Reader or input stream associated with this
	 * buffered reader.
	 *
	 * @throws IOException if error encountered while closing.
	 */
	abstract public void close()	throws IOException;

}
