com.viaoa.image.jpg.ImageInputStreamImpl2 Maven / Gradle / Ivy
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/*
* @(#)ImageInputStreamImpl2.java
*
* Copyright (c) 2011 Werner Randelshofer, Immensee, Switzerland.
* All rights reserved.
*
* You may not use, copy or modify this file, except in compliance with the
* license agreement you entered into with Werner Randelshofer.
* For details see accompanying license terms.
*/
package com.viaoa.image.jpg;
import java.io.IOException;
import java.nio.ByteOrder;
import javax.imageio.stream.ImageInputStreamImpl;
/**
* {@code ImageInputStreamImpl2} fixes bugs in ImageInputStreamImpl.
*
* ImageInputStreamImpl uses read(byte[]) instead of readFully(byte[]) inside of
* readShort. This results in corrupt data input if the underlying stream can
* not fulfill the read operation in a single step.
*
* @author Werner Randelshofer
* @version $Id: ImageInputStreamImpl2.java 134 2011-12-02 16:23:00Z werner $
*/
public abstract class ImageInputStreamImpl2 extends ImageInputStreamImpl {
// Length of the buffer used for readFully(type[], int, int)
private static final int BYTE_BUF_LENGTH = 8192;
/**
* Byte buffer used for readFully(type[], int, int). Note that this
* array is also used for bulk reads in readShort(), readInt(), etc, so
* it should be large enough to hold a primitive value (i.e. >= 8 bytes).
* Also note that this array is package protected, so that it can be
* used by ImageOutputStreamImpl in a similar manner.
*/
byte[] byteBuf = new byte[BYTE_BUF_LENGTH];
@Override
public short readShort() throws IOException {
readFully(byteBuf, 0, 2);
if (byteOrder == ByteOrder.BIG_ENDIAN) {
return (short)
(((byteBuf[0] & 0xff) << 8) | ((byteBuf[1] & 0xff) << 0));
} else {
return (short)
(((byteBuf[1] & 0xff) << 8) | ((byteBuf[0] & 0xff) << 0));
}
}
public int readInt() throws IOException {
readFully(byteBuf, 0, 4);
if (byteOrder == ByteOrder.BIG_ENDIAN) {
return
(((byteBuf[0] & 0xff) << 24) | ((byteBuf[1] & 0xff) << 16) |
((byteBuf[2] & 0xff) << 8) | ((byteBuf[3] & 0xff) << 0));
} else {
return
(((byteBuf[3] & 0xff) << 24) | ((byteBuf[2] & 0xff) << 16) |
((byteBuf[1] & 0xff) << 8) | ((byteBuf[0] & 0xff) << 0));
}
}
}