/*
 * @(#)ImageReader.java	1.140 03/08/27
 *
 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package javax.imageio;

import java.awt.Point;
import java.awt.Rectangle;
import java.awt.image.BufferedImage;
import java.awt.image.Raster;
import java.awt.image.RenderedImage;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Locale;
import java.util.MissingResourceException;
import java.util.ResourceBundle;
import java.util.Set;
import javax.imageio.spi.ImageReaderSpi;
import javax.imageio.event.IIOReadWarningListener;
import javax.imageio.event.IIOReadProgressListener;
import javax.imageio.event.IIOReadUpdateListener;
import javax.imageio.metadata.IIOMetadata;
import javax.imageio.metadata.IIOMetadataFormatImpl;
import javax.imageio.stream.ImageInputStream;

/**
 * An abstract superclass for parsing and decoding of images.  This
 * class must be subclassed by classes that read in images in the
 * context of the Java Image I/O framework.
 *
 * <p> <code>ImageReader</code> objects are normally instantiated by
 * the service provider interface (SPI) class for the specific format.
 * Service provider classes (e.g., instances of
 * <code>ImageReaderSpi</code>) are registered with the
 * <code>IIORegistry</code>, which uses them for format recognition
 * and presentation of available format readers and writers.
 *
 * <p> When an input source is set (using the <code>setInput</code>
 * method), it may be marked as "seek forward only".  This setting
 * means that images contained within the input source will only be
 * read in order, possibly allowing the reader to avoid caching
 * portions of the input containing data associated with images that
 * have been read previously.
 *
 * @see ImageWriter
 * @see javax.imageio.spi.IIORegistry
 * @see javax.imageio.spi.ImageReaderSpi
 *
 * @version 0.5
 */
public abstract class ImageReader {

    /**
     * The <code>ImageReaderSpi</code> that instantiated this object,
     * or <code>null</code> if its identity is not known or none
     * exists.  By default it is initialized to <code>null</code>.
     */
    protected ImageReaderSpi originatingProvider;

    /**
     * The <code>ImageInputStream</code> or other
     * <code>Object</code> by <code>setInput</code> and retrieved
     * by <code>getInput</code>.  By default it is initialized to
     * <code>null</code>.
     */
    protected Object input = null;

    /**
     * <code>true</code> if the current input source has been marked
     * as allowing only forward seeking by <code>setInput</code>.  By
     * default, the value is <code>false</code>.
     *
     * @see #minIndex
     * @see #setInput
     */
    protected boolean seekForwardOnly = false;

    /**
     * <code>true</code> if the current input source has been marked
     * as allowing metadata to be ignored by <code>setInput</code>.
     * By default, the value is <code>false</code>.
     *
     * @see #setInput
     */
    protected boolean ignoreMetadata = false;

    /**
     * The smallest valid index for reading, initially 0.  When
     * <code>seekForwardOnly</code> is <code>true</code>, various methods
     * may throw an <code>IndexOutOfBoundsException</code> on an
     * attempt to access data associate with an image having a lower
     * index.
     *
     * @see #seekForwardOnly
     * @see #setInput