rlm@10: /*
rlm@10:  * @(#)SeekableByteArrayOutputStream.java  1.0  2010-12-27
rlm@10:  * 
rlm@10:  * Copyright © 2010 Werner Randelshofer, Immensee, Switzerland.
rlm@10:  * All rights reserved.
rlm@10:  * 
rlm@10:  * You may not use, copy or modify this file, except in compliance with the
rlm@10:  * license agreement you entered into with Werner Randelshofer.
rlm@10:  * For details see accompanying license terms.
rlm@10:  */
rlm@10: 
rlm@10: package ca.randelshofer;
rlm@10: 
rlm@10: import java.io.ByteArrayOutputStream;
rlm@10: import java.io.IOException;
rlm@10: import java.io.OutputStream;
rlm@10: import java.util.Arrays;
rlm@10: import static java.lang.Math.*;
rlm@10: /**
rlm@10:  * {@code SeekableByteArrayOutputStream}.
rlm@10:  *
rlm@10:  * @author Werner Randelshofer
rlm@10:  * @version 1.0 2010-12-27 Created.
rlm@10:  */
rlm@10: public class SeekableByteArrayOutputStream extends ByteArrayOutputStream {
rlm@10: 
rlm@10:     /**
rlm@10:      * The current stream position.
rlm@10:      */
rlm@10:     private int pos;
rlm@10: 
rlm@10:     /**
rlm@10:      * Creates a new byte array output stream. The buffer capacity is
rlm@10:      * initially 32 bytes, though its size increases if necessary.
rlm@10:      */
rlm@10:     public SeekableByteArrayOutputStream() {
rlm@10: 	this(32);
rlm@10:     }
rlm@10: 
rlm@10:     /**
rlm@10:      * Creates a new byte array output stream, with a buffer capacity of
rlm@10:      * the specified size, in bytes.
rlm@10:      *
rlm@10:      * @param   size   the initial size.
rlm@10:      * @exception  IllegalArgumentException if size is negative.
rlm@10:      */
rlm@10:     public SeekableByteArrayOutputStream(int size) {
rlm@10:         if (size < 0) {
rlm@10:             throw new IllegalArgumentException("Negative initial size: "
rlm@10:                                                + size);
rlm@10:         }
rlm@10: 	buf = new byte[size];
rlm@10:     }
rlm@10: 
rlm@10:     /**
rlm@10:      * Writes the specified byte to this byte array output stream.
rlm@10:      *
rlm@10:      * @param   b   the byte to be written.
rlm@10:      */
rlm@10:     @Override
rlm@10:     public synchronized void write(int b) {
rlm@10: 	int newcount = max(pos + 1, count);
rlm@10: 	if (newcount > buf.length) {
rlm@10:             buf = Arrays.copyOf(buf, Math.max(buf.length << 1, newcount));
rlm@10: 	}
rlm@10: 	buf[pos++] = (byte)b;
rlm@10: 	count = newcount;
rlm@10:     }
rlm@10: 
rlm@10:     /**
rlm@10:      * Writes <code>len</code> bytes from the specified byte array
rlm@10:      * starting at offset <code>off</code> to this byte array output stream.
rlm@10:      *
rlm@10:      * @param   b     the data.
rlm@10:      * @param   off   the start offset in the data.
rlm@10:      * @param   len   the number of bytes to write.
rlm@10:      */
rlm@10:     @Override
rlm@10:     public synchronized void write(byte b[], int off, int len) {
rlm@10: 	if ((off < 0) || (off > b.length) || (len < 0) ||
rlm@10:             ((off + len) > b.length) || ((off + len) < 0)) {
rlm@10: 	    throw new IndexOutOfBoundsException();
rlm@10: 	} else if (len == 0) {
rlm@10: 	    return;
rlm@10: 	}
rlm@10:         int newcount = max(pos+len,count);
rlm@10:         if (newcount > buf.length) {
rlm@10:             buf = Arrays.copyOf(buf, Math.max(buf.length << 1, newcount));
rlm@10:         }
rlm@10:         System.arraycopy(b, off, buf, pos, len);
rlm@10:         pos+=len;
rlm@10:         count = newcount;
rlm@10:     }
rlm@10: 
rlm@10:     /**
rlm@10:      * Resets the <code>count</code> field of this byte array output
rlm@10:      * stream to zero, so that all currently accumulated output in the
rlm@10:      * output stream is discarded. The output stream can be used again,
rlm@10:      * reusing the already allocated buffer space.
rlm@10:      *
rlm@10:      * @see     java.io.ByteArrayInputStream#count
rlm@10:      */
rlm@10:     @Override
rlm@10:     public synchronized void reset() {
rlm@10: 	count = 0;
rlm@10:         pos=0;
rlm@10:     }
rlm@10: 
rlm@10:     /**
rlm@10:      * Sets the current stream position to the desired location.  The
rlm@10:      * next read will occur at this location.  The bit offset is set
rlm@10:      * to 0.
rlm@10:      *
rlm@10:      * <p> An <code>IndexOutOfBoundsException</code> will be thrown if
rlm@10:      * <code>pos</code> is smaller than the flushed position (as
rlm@10:      * returned by <code>getflushedPosition</code>).
rlm@10:      *
rlm@10:      * <p> It is legal to seek past the end of the file; an
rlm@10:      * <code>EOFException</code> will be thrown only if a read is
rlm@10:      * performed.
rlm@10:      *
rlm@10:      * @param pos a <code>long</code> containing the desired file
rlm@10:      * pointer position.
rlm@10:      *
rlm@10:      * @exception IndexOutOfBoundsException if <code>pos</code> is smaller
rlm@10:      * than the flushed position.
rlm@10:      * @exception IOException if any other I/O error occurs.
rlm@10:      */
rlm@10:     public void seek(long pos) throws IOException {
rlm@10:         this.pos = (int)pos;
rlm@10:     }
rlm@10: 
rlm@10:         /**
rlm@10:      * Returns the current byte position of the stream.  The next write
rlm@10:      * will take place starting at this offset.
rlm@10:      *
rlm@10:      * @return a long containing the position of the stream.
rlm@10:      *
rlm@10:      * @exception IOException if an I/O error occurs.
rlm@10:      */
rlm@10:     public long getStreamPosition() throws IOException {
rlm@10:         return pos;
rlm@10:     }
rlm@10: 
rlm@10:     /** Writes the contents of the byte array into the specified output
rlm@10:      * stream.
rlm@10:      * @param out
rlm@10:      */
rlm@10:     public void toOutputStream(OutputStream out) throws IOException {
rlm@10:         out.write(buf, 0, count);
rlm@10:     }
rlm@10: 
rlm@10: }