package LBJ2.io;
import java.io.IOException;
import java.io.OutputStream;
/**
* This class will convert whatever data is sent to it into little endian,
* hexidecimal text and send that text on to another
* <code>OutputStream</code>. The most common usage of this class will
* involve passing it to the constructor of another
* <code>OutputStream</code>. For instance: <br><br>
*
* <pre>
* ObjectOutputStream oos =
* new ObjectOutputStream(
* new GZIPOutputStream(
* new HexOutputStream(new FileOutputStream(fileName))));
* </pre>
*
* @see HexInputStream
* @author Nick Rizzolo
**/
public class HexOutputStream extends OutputStream
{
/** Characters representing a hexidecimal digit. */
private static final String digits = "0123456789ABCDEF";
/**
* The <code>OutputStream</code> to which converted output should be sent.
**/
private OutputStream out;
/**
* Initializes this stream with another output stream.
*
* @param o The output stream to which converted output should be sent.
**/
public HexOutputStream(OutputStream o) { out = o; }
/**
* Writes the specified byte to this output stream. The general contract
* for <code>write</code> is that one byte is written to the output stream.
* The byte to be written is the eight low-order bits of the argument
* <code>b</code>. The 24 high-order bits of <code>b</code> are ignored.
*
* @param b The byte to be written.
**/
public void write(int b) throws IOException {
b &= 255;
out.write(digits.charAt(b & 15));
out.write(digits.charAt((b & 240) >> 4));
}
/**
* Writes <code>b.length</code> bytes from the specified byte array to this
* output stream. The general contract for <code>write(b)</code> is that
* it should have exactly the same effect as the call <code>write(b, 0,
* b.length)</code>.
*
* @param b The bytes to be written.
**/
public void write(byte[] b) throws IOException {
write(b, 0, b.length);
}
/**
* Writes <code>len</code> bytes from the specified byte array starting at
* offset <code>off</code> to this output stream. The general contract for
* <code>write(b, off, len)</code> is that some of the bytes in the array
* <code>b</code> are written to the output stream in order; element
* <code>b[off]</code> is the first byte written and
* <code>b[off+len-1]</code> is the last byte written by this operation.
* <br><br>
*
* If <code>b</code> is <code>null</code>, a
* <code>NullPointerException</code> is thrown. <br><br>
*
* If <code>off</code> is negative, or <code>len</code> is negative, or
* <code>off+len</code> is greater than the length of the array
* <code>b</code>, then an <code>IndexOutOfBoundsException</code> is
* thrown.
*
* @param b A buffer containing the bytes to be written.
* @param off The offset of the first byte to be written.
* @param len The amount of bytes to be written.
**/
public void write(byte[] b, int off, int len) throws IOException {
byte[] hex = new byte[2 * len];
for (int i = 0; i < len; ++i) {
hex[2 * i] = (byte) digits.charAt(b[off + i] & 15);
hex[2 * i + 1] = (byte) digits.charAt((b[off + i] & 240) >> 4);
}
out.write(hex);
}
/**
* Flushes this output stream and forces any buffered output bytes to be
* written out. The general contract of <code>flush</code> is that calling
* it is an indication that, if any bytes previously written have been
* buffered by the implementation of the output stream, such bytes should
* immediately be written to their intended destination.
**/
public void flush() throws IOException { out.flush(); }
/**
* Closes this output stream and releases any system resources associated
* with this stream. The general contract of <code>close</code> is that it
* closes the output stream. A closed stream cannot perform output
* operations and cannot be reopened.
**/
public void close() throws IOException { out.close(); }
}