com.viaoa.image.jpg.ImageInputStreamAdapter Maven / Gradle / Ivy
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/*
* @(#)ImageInputStreamAdapter.java 1.0 2009-12-17
*
* Copyright (c) 2009 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.FilterInputStream;
import java.io.IOException;
import javax.imageio.stream.ImageInputStream;
/**
* ImageInputStreamAdapter.
*
* @author Werner Randelshofer
* @version 1.0 2009-12-17 Created.
*/
public class ImageInputStreamAdapter extends FilterInputStream {
private ImageInputStream iis;
public ImageInputStreamAdapter(ImageInputStream iis) {
super(null);
this.iis=iis;
}
/**
* 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 method blocks until input data
* is available, the end of the stream is detected, or an exception
* is thrown.
*
* This method
* simply performs in.read() and returns the result.
*
* @return the next byte of data, or -1 if the end of the
* stream is reached.
* @exception IOException if an I/O error occurs.
* @see java.io.FilterInputStream#in
*/
@Override
public int read() throws IOException {
return iis.read();
}
/**
* Reads up to len bytes of data from this input stream
* into an array of bytes. If len is not zero, the method
* blocks until some input is available; otherwise, no
* bytes are read and 0 is returned.
*
* This method simply performs in.read(b, off, len)
* and returns the result.
*
* @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
* @exception IOException if an I/O error occurs.
* @see java.io.FilterInputStream#in
*/
@Override
public int read(byte b[], int off, int len) throws IOException {
return iis.read(b, off, len);
}
/**
* {@inheritDoc}
*
* This method simply performs in.skip(n).
*/
@Override
public long skip(long n) throws IOException {
return iis.skipBytes(n);
}
/**
* Returns an estimate of the number of bytes that can be read (or
* skipped over) from this input stream without blocking by the next
* caller of a method for this input stream. The next caller might be
* the same thread or another thread. A single read or skip of this
* many bytes will not block, but may read or skip fewer bytes.
*
* This method returns the result of {@link #in in}.available().
*
* @return an estimate of the number of bytes that can be read (or skipped
* over) from this input stream without blocking.
* @exception IOException if an I/O error occurs.
*/
@Override
public int available() throws IOException {
return (iis.isCached()) ? //
(int)Math.min(Integer.MAX_VALUE, iis.length() - iis.getStreamPosition()) :
0;
}
/**
* Closes this input stream and releases any system resources
* associated with the stream.
* This
* method simply performs in.close().
*
* @exception IOException if an I/O error occurs.
* @see java.io.FilterInputStream#in
*/
@Override
public void close() throws IOException {
iis.close();
}
/**
* Marks the current position in this input stream. A subsequent
* call to the reset method repositions this stream at
* the last marked position so that subsequent reads re-read the same bytes.
*
* The readlimit argument tells this input stream to
* allow that many bytes to be read before the mark position gets
* invalidated.
*
* This method simply performs in.mark(readlimit).
*
* @param readlimit the maximum limit of bytes that can be read before
* the mark position becomes invalid.
* @see java.io.FilterInputStream#in
* @see java.io.FilterInputStream#reset()
*/
@Override
public synchronized void mark(int readlimit) {
iis.mark();
}
/**
* Repositions this stream to the position at the time the
* mark method was last called on this input stream.
*
* This method
* simply performs in.reset().
*
* Stream marks are intended to be used in
* situations where you need to read ahead a little to see what's in
* the stream. Often this is most easily done by invoking some
* general parser. If the stream is of the type handled by the
* parse, it just chugs along happily. If the stream is not of
* that type, the parser should toss an exception when it fails.
* If this happens within readlimit bytes, it allows the outer
* code to reset the stream and try another parser.
*
* @exception IOException if the stream has not been marked or if the
* mark has been invalidated.
* @see java.io.FilterInputStream#in
* @see java.io.FilterInputStream#mark(int)
*/
@Override
public synchronized void reset() throws IOException {
iis.reset();
}
/**
* Tests if this input stream supports the mark
* and reset methods.
* This method
* simply performs in.markSupported().
*
* @return true if this stream type supports the
* mark and reset method;
* false otherwise.
* @see java.io.FilterInputStream#in
* @see java.io.InputStream#mark(int)
* @see java.io.InputStream#reset()
*/
@Override
public boolean markSupported() {
return true;
}
}