package org.openedit.util;
import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
/**
* Adapts a <code>Reader</code> as an <code>InputStream</code>. Adapted
* from <CODE>StringInputStream</CODE>.
*
*/
public class ReaderInputStream extends InputStream
{
/** Source Reader */
private Reader in;
private String encoding = System.getProperty("file.encoding");
private byte[] slack;
private int begin;
/**
* Construct a <CODE>ReaderInputStream</CODE> for the specified <CODE>Reader</CODE>.
*
* @param reader
* <CODE>Reader</CODE>. Must not be <code>null</code>.
*/
public ReaderInputStream(Reader reader)
{
in = reader;
}
/**
* Construct a <CODE>ReaderInputStream</CODE> for the specified <CODE>Reader</CODE>,
* with the specified encoding.
*
* @param reader
* non-null <CODE>Reader</CODE>.
* @param encoding
* non-null <CODE>String</CODE> encoding.
*/
public ReaderInputStream(Reader reader, String encoding)
{
this(reader);
if (encoding == null)
{
throw new IllegalArgumentException("encoding must not be null");
}
else
{
this.encoding = encoding;
}
}
/**
* Reads from the <CODE>Reader</CODE>, returning the same value.
*
* @return the value of the next character in the <CODE>Reader</CODE>.
*
* @exception IOException
* if the original <code>Reader</code> fails to be read
*/
public synchronized int read() throws IOException
{
if (in == null)
{
throw new IOException("Stream Closed");
}
byte result;
if (slack != null && begin < slack.length)
{
result = slack[begin];
if (++begin == slack.length)
{
slack = null;
}
}
else
{
byte[] buf = new byte[1];
if (read(buf, 0, 1) <= 0)
{
result = -1;
}
result = buf[0];
}
if (result < -1)
{
result += 256;
}
return result;
}
/**
* Reads from the <code>Reader</code> into a byte array
*
* @param b
* the byte array to read into
* @param off
* the offset in the byte array
* @param len
* the length in the byte array to fill
* @return the actual number read into the byte array, -1 at the end of the
* stream
* @exception IOException
* if an error occurs
*/
public synchronized int read(byte[] b, int off, int len) throws IOException
{
if (in == null)
{
throw new IOException("Stream Closed");
}
while (slack == null)
{
char[] buf = new char[len]; // might read too much
int n = in.read(buf);
if (n == -1)
{
return -1;
}
if (n > 0)
{
slack = new String(buf, 0, n).getBytes(encoding);
begin = 0;
}
}
if (len > slack.length - begin)
{
len = slack.length - begin;
}
System.arraycopy(slack, begin, b, off, len);
if ((begin += len) >= slack.length)
{
slack = null;
}
return len;
}
/**
* Marks the read limit of the StringReader.
*
* @param limit
* the maximum limit of bytes that can be read before the mark
* position becomes invalid
*/
public synchronized void mark(final int limit)
{
try
{
in.mark(limit);
}
catch (IOException ioe)
{
throw new RuntimeException(ioe.getMessage());
}
}
/**
* @return the current number of bytes ready for reading
* @exception IOException
* if an error occurs
*/
public synchronized int available() throws IOException
{
if (in == null)
{
throw new IOException("Stream Closed");
}
if (slack != null)
{
return slack.length - begin;
}
if (in.ready())
{
return 1;
}
else
{
return 0;
}
}
/**
* @return false - mark is not supported
*/
public boolean markSupported()
{
return false; // would be imprecise
}
/**
* Resets the StringReader.
*
* @exception IOException
* if the StringReader fails to be reset
*/
public synchronized void reset() throws IOException
{
if (in == null)
{
throw new IOException("Stream Closed");
}
slack = null;
in.reset();
}
/**
* Closes the Stringreader.
*
* @exception IOException
* if the original StringReader fails to be closed
*/
public synchronized void close() throws IOException
{
if (in != null)
{
in.close();
slack = null;
in = null;
}
}
}