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package org.apache.juneau.parser;

import java.io.*;

/**
 * Input stream meant to be used as input for stream-based parsers.
 *
 * <p>
 * Keeps track of current byte position.
 *
 * <ul class='notes'>
 * 	<li class='warn'>This class is not thread safe.
 * </ul>
 *
 * <ul class='seealso'>
 * 	<li class='link'>{@doc jm.SerializersAndParsers}
 * 	<li class='extlink'>{@source}
 * </ul>
 */
public class ParserInputStream extends InputStream implements Positionable {

	private final InputStream is;
	int pos = 0;

	/**
	 * Constructor.
	 *
	 * @param pipe The parser input.
	 * @throws IOException Thrown by underlying stream.
	 */
	protected ParserInputStream(ParserPipe pipe) throws IOException {
		this.is = pipe.getInputStream();
		pipe.setPositionable(this);
	}

	@Override /* InputStream */
	public int read() throws IOException {
		int i = is.read();
		if (i > 0)
			pos++;
		return i;
	}

	@Override /* Positionable */
	public Position getPosition() {
		return new Position(pos);
	}
}
