org.monte.media.io.ByteArrayImageOutputStream Maven / Gradle / Ivy
/*
* @(#)ByteArrayImageOutputStream.java 1.0.1 2011-01-23
*
* Copyright (c) 2011 Werner Randelshofer
* Staldenmattweg 2, Goldau, CH-6405, Switzerland.
* All rights reserved.
*
* The copyright of this software is owned by Werner Randelshofer.
* You may not use, copy or modify this software, except in
* accordance with the license agreement you entered into with
* Werner Randelshofer. For details see accompanying license terms.
*/
package org.monte.media.io;
import java.io.OutputStream;
import javax.imageio.stream.ImageOutputStreamImpl;
import java.io.ByteArrayOutputStream;
import javax.imageio.stream.ImageOutputStream;
import java.io.IOException;
import java.util.Arrays;
import java.nio.ByteOrder;
import static java.lang.Math.*;
/**
* This class implements an image output stream in which the data is
* written into a byte array. The buffer automatically grows as data
* is written to it.
* The data can be retrieved using {@code toByteArray()}, {@code toImageOutputStream()}
* and {@code toOutputStream()}.
*
* Closing a {@code ByteArrayImageOutputStream} has no effect. The methods in
* this class can be called after the stream has been closed without
* generating an {@code IOException}.
*
* @author Werner Randelshofer
* @version 1.0.1 2011-01-23 Implements length method.
*
1.0 2011-01-18 Created.
*/
public class ByteArrayImageOutputStream extends ImageOutputStreamImpl {
/**
* An array of bytes that was provided
* by the creator of the stream. Elements buf[0]
* through buf[count-1] are the
* only bytes that can ever be read from the
* stream; element buf[streamPos] is
* the next byte to be read.
*/
protected byte buf[];
/**
* The index one greater than the last valid character in the input
* stream buffer.
* This value should always be nonnegative
* and not larger than the length of buf.
* It is one greater than the position of
* the last byte within buf that
* can ever be read from the input stream buffer.
*/
protected int count;
/** The offset to the start of the array. */
private final int arrayOffset;
public ByteArrayImageOutputStream() {
this(16);
}
public ByteArrayImageOutputStream(int initialCapacity) {
this(new byte[initialCapacity]);
}
public ByteArrayImageOutputStream(byte[] buf) {
this(buf, ByteOrder.BIG_ENDIAN);
}
public ByteArrayImageOutputStream(byte[] buf, ByteOrder byteOrder) {
this(buf, 0, buf.length, byteOrder);
}
public ByteArrayImageOutputStream(byte[] buf, int offset, int length, ByteOrder byteOrder) {
this.buf = buf;
this.streamPos = offset;
this.count = Math.min(offset + length, buf.length);
this.arrayOffset = offset;
this.byteOrder = byteOrder;
}
public ByteArrayImageOutputStream(ByteOrder byteOrder) {
this(new byte[16],byteOrder);
}
/**
* Reads the next byte of data from this input stream. The value
* byte is returned as an int in the range
* 0 to 255. If no byte is available
* because the end of the stream has been reached, the value
* -1 is returned.
*
* This read method
* cannot block.
*
* @return the next byte of data, or -1 if the end of the
* stream has been reached.
*/
@Override
public synchronized int read() throws IOException {
flushBits();
return (streamPos < count) ? (buf[(int) (streamPos++)] & 0xff) : -1;
}
/**
* Reads up to len bytes of data into an array of bytes
* from this input stream.
* If streamPos equals count,
* then -1 is returned to indicate
* end of file. Otherwise, the number k
* of bytes read is equal to the smaller of
* len and count-streamPos.
* If k is positive, then bytes
* buf[streamPos] through buf[streamPos+k-1]
* are copied into b[off] through
* b[off+k-1] in the manner performed
* by System.arraycopy. The
* value k is added into streamPos
* and k is returned.
*
* This read method cannot block.
*
* @param b the buffer into which the data is read.
* @param off the start offset in the destination array b
* @param len the maximum number of bytes read.
* @return the total number of bytes read into the buffer, or
* -1 if there is no more data because the end of
* the stream has been reached.
* @exception NullPointerException If b is null.
* @exception IndexOutOfBoundsException If off is negative,
* len is negative, or len is greater than
* b.length - off
*/
@Override
public synchronized int read(byte b[], int off, int len) throws IOException {
flushBits();
if (b == null) {
throw new NullPointerException();
} else if (off < 0 || len < 0 || len > b.length - off) {
throw new IndexOutOfBoundsException();
}
if (streamPos >= count) {
return -1;
}
if (streamPos + len > count) {
len = (int) (count - streamPos);
}
if (len <= 0) {
return 0;
}
System.arraycopy(buf, (int) streamPos, b, off, len);
streamPos += len;
return len;
}
/**
* Skips n bytes of input from this input stream. Fewer
* bytes might be skipped if the end of the input stream is reached.
* The actual number k
* of bytes to be skipped is equal to the smaller
* of n and count-streamPos.
* The value k is added into streamPos
* and k is returned.
*
* @param n the number of bytes to be skipped.
* @return the actual number of bytes skipped.
*/
public synchronized long skip(long n) {
if (streamPos + n > count) {
n = count - streamPos;
}
if (n < 0) {
return 0;
}
streamPos += n;
return n;
}
/**
* Returns the number of remaining bytes that can be read (or skipped over)
* from this input stream.
*
* The value returned is count - streamPos,
* which is the number of bytes remaining to be read from the input buffer.
*
* @return the number of remaining bytes that can be read (or skipped
* over) from this input stream without blocking.
*/
public synchronized int available() {
return (int) (count - streamPos);
}
/**
* Closing a ByteArrayInputStream has no effect. The methods in
* this class can be called after the stream has been closed without
* generating an IOException.
*
*/
@Override
public void close() {
// does nothing!!
}
@Override
public long getStreamPosition() throws IOException {
checkClosed();
return streamPos - arrayOffset;
}
@Override
public void seek(long pos) throws IOException {
checkClosed();
flushBits();
// This test also covers pos < 0
if (pos < flushedPos) {
throw new IndexOutOfBoundsException("pos < flushedPos!");
}
this.streamPos = pos + arrayOffset;
}
/**
* Writes the specified byte to this output stream.
*
* @param b the byte to be written.
*/
@Override
public synchronized void write(int b) throws IOException {
flushBits();
long newcount = max(streamPos + 1, count);
if (newcount> Integer.MAX_VALUE) {
throw new IndexOutOfBoundsException(newcount+" > max array size");
}
if (newcount > buf.length) {
buf = Arrays.copyOf(buf, max(buf.length << 1, (int) newcount));
}
buf[(int) streamPos++] = (byte) b;
count = (int)newcount;
}
/**
* Writes the specified byte array to this output stream.
*
* @param b the data.
*/
@Override
public synchronized void write(byte b[]) throws IOException {
write(b, 0, b.length);
}
/**
* Writes len bytes from the specified byte array
* starting at offset off to this output stream.
*
* @param b the data.
* @param off the start offset in the data.
* @param len the number of bytes to write.
*/
@Override
public synchronized void write(byte b[], int off, int len) throws IOException {
flushBits();
if ((off < 0) || (off > b.length) || (len < 0)
|| ((off + len) > b.length) || ((off + len) < 0)) {
throw new IndexOutOfBoundsException("off="+off+", len="+len+", b.length="+b.length);
} else if (len == 0) {
return;
}
int newcount = max((int) streamPos + len, count);
if (newcount > buf.length) {
buf = Arrays.copyOf(buf, Math.max(buf.length << 1, newcount));
}
System.arraycopy(b, off, buf, (int) streamPos, len);
streamPos += len;
count = newcount;
}
/** Writes the contents of the byte array into the specified output
* stream.
* @param out
*/
public void toOutputStream(OutputStream out) throws IOException {
out.write(buf, arrayOffset, count);
}
/** Writes the contents of the byte array into the specified image output
* stream.
* @param out
*/
public void toImageOutputStream(ImageOutputStream out) throws IOException {
out.write(buf, arrayOffset, count);
}
/**
* Creates a newly allocated byte array. Its size is the current
* size of this output stream and the valid contents of the buffer
* have been copied into it.
*
* @return the current contents of this output stream, as a byte array.
* @see java.io.ByteArrayOutputStream#size()
*/
public synchronized byte[] toByteArray() {
byte[] copy = new byte[count - arrayOffset];
System.arraycopy(buf, arrayOffset, copy, 0, count);
return copy;
}
/** Returns the internally used byte buffer. */
public byte[] getBuffer() {
return buf;
}
@Override
public long length() {
return count-arrayOffset;
}
/**
* Resets the count field of this byte array output
* stream to zero, so that all currently accumulated output in the
* output stream is discarded. The output stream can be used again,
* reusing the already allocated buffer space.
*
* @see java.io.ByteArrayInputStream#count
*/
public synchronized void clear() {
count = arrayOffset;
streamPos=arrayOffset;
}
}