import java.io.Reader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.ByteArrayInputStream;

import java.io.IOException;
import java.io.EOFException;
import java.io.CharConversionException;
import java.io.UnsupportedEncodingException;

/**
 * AutoInputStreamReader is like InputStreamReader, but detects the used
 * character encoding automatically, from a list of possible choices.
 *
 * @author	Fredrik Roubert <roubert@df.lth.se>
 * @version	21 March 2003
 *
 * @see		java.io.InputStreamReader
 */
public class AutoInputStreamReader extends Reader
{
	protected InputStreamReader isr;

	AutoInputStreamReader(InputStream is, String encs[])
	throws IOException, UnsupportedEncodingException
	{
		ByteArrayInputStream bais;
		byte buf[];
		int len;

		if ((len = is.available()) < 1)
			throw new EOFException();

		buf = new byte[len];
		if (is.read(buf) < 1)
			throw new EOFException();

		is.close();
		bais = new ByteArrayInputStream(buf);

		for (int i = 0; i < encs.length; i ++)
		{
			isr = new InputStreamReader(bais, encs[i]);

			try
			{
				while (isr.read() != -1)
					;
			}
			catch (CharConversionException e)
			{
				bais.reset();
				isr.close();
				continue;
			}

			bais.reset();
			isr.close();
			isr = new InputStreamReader(bais, encs[i]);
			return;
		}

		throw new UnsupportedEncodingException();
	}

	public String getEncoding()
	{
		return isr.getEncoding();
	}

	public void close()
	throws IOException
	{
		isr.close();
	}

	public void mark(int readAheadLimit)
	throws IOException
	{
		isr.mark(readAheadLimit);
	}

	public boolean markSupported()
	{
		return isr.markSupported();
	}

	public int read()
	throws IOException
	{
		return isr.read();
	}

	public int read(char[] cbuf)
	throws IOException
	{
		return isr.read(cbuf);
	}

	public int read(char[] cbuf, int off, int len)
	throws IOException
	{
		return isr.read(cbuf, off, len);
	}

	public boolean ready()
	throws IOException
	{
		return isr.ready();
	}

	public void reset()
	throws IOException
	{
		isr.reset();
	}

	public long skip(long n)
	throws IOException
	{
		return isr.skip(n);
	}
}