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Freedom for Media in Java

There is a newer version: 1.0.2-jitsi

package net.sf.fmj.utility;

import java.io.*;

/**
 * Represents a byte array as an OutputStream.
 *
 * @author Lyubomir Marinov
 */
public class ByteBufferOutputStream
    extends OutputStream
{
    /**
     * The index within {@link #buf} which was initially writable.
     */
    private final int beginIndex;

    /**
     * The byte array represented as an OutputStream by this
     * instance.
     */
    private final byte[] buf;

    /**
     * The index right after the last writable index within {@link #buf}.
     */
    private final int endIndex;

    /**
     * The first writable index within {@link #buf}.
     */
    private int index;

    /**
     * Initializes a new ByteBufferOutputStream instance which is to
     * represent a specific byte array as an OutputStream.
     *
     * @param buf the byte array for which the new instance is to
     * implement OutputStream
     */
    public ByteBufferOutputStream(byte[] buf)
    {
        this(buf, 0, buf.length);
    }

    /**
     * Initializes a new ByteBufferOutputStream instance which is to
     * represent a specific byte array as an OutputStream.
     *
     * @param buf the byte array for which the new instance is to
     * implement OutputStream
     * @param off
     * @param len
     */
    public ByteBufferOutputStream(byte[] buf, int off, int len)
    {
        if (buf == null)
            throw new NullPointerException("buf");
        if (off < 0)
            throw new IndexOutOfBoundsException("off");
        if (len > buf.length)
            throw new IndexOutOfBoundsException("len");

        this.buf = buf;
        this.beginIndex = off;
        this.index = off;
        this.endIndex = off + len;
    }

    /**
     * Returns the number of bytes written into this OutputStream.
     *
     * @return the number of bytes written into this OutputStream
     */
    public int size()
    {
        return index - beginIndex;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void write(int b)
        throws IOException
    {
        if (index >= endIndex)
        {
            throw new IOException(
                    "This " + ByteBufferOutputStream.class.getName()
                        + " is fully written.");
        }
        else
        {
            buf[index++] = (byte) b;
        }
    }
}