/*

 * Copyright (c) 2001, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package com.sun.imageio.plugins.jpeg;

import javax.imageio.metadata.IIOMetadataNode;

import javax.imageio.stream.ImageOutputStream;

import javax.imageio.metadata.IIOInvalidTreeException;

import java.io.IOException;

import java.io.UnsupportedEncodingException;

import org.w3c.dom.Node;

/**

 * A Comment marker segment.  Retains an array of bytes representing the

 * comment data as it is read from the stream.  If the marker segment is

 * constructed from a String, then local default encoding is assumed

 * when creating the byte array.  If the marker segment is created from

 * an <code>IIOMetadataNode</code>, the user object, if present is

 * assumed to be a byte array containing the comment data.  If there is

 * no user object then the comment attribute is used to create the

 * byte array, again assuming the default local encoding.

 */

class COMMarkerSegment extends MarkerSegment {

    private static final String ENCODING = "ISO-8859-1";

    /**

     * Constructs a marker segment from the given buffer, which contains

     * data from an <code>ImageInputStream</code>.  This is used when

     * reading metadata from a stream.

     */

    COMMarkerSegment(JPEGBuffer buffer) throws IOException {

        super(buffer);

        loadData(buffer);

    }

    /**

     * Constructs a marker segment from a String.  This is used when

     * modifying metadata from a non-native tree and when transcoding.

     * The default encoding is used to construct the byte array.

     */

    COMMarkerSegment(String comment) {

        super(JPEG.COM);

        data = comment.getBytes(); // Default encoding

    }

    /**

     * Constructs a marker segment from a native tree node.  If the node

     * is an <code>IIOMetadataNode</code> and contains a user object,

     * that object is used rather than the string attribute.  If the

     * string attribute is used, the default encoding is used.

     */

    COMMarkerSegment(Node node) throws IIOInvalidTreeException{

        super(JPEG.COM);

        if (node instanceof IIOMetadataNode) {

            IIOMetadataNode ourNode = (IIOMetadataNode) node;

            data = (byte []) ourNode.getUserObject();

        }

        if (data == null) {

            String comment =

                node.getAttributes().getNamedItem("comment").getNodeValue();

            if (comment != null) {

                data = comment.getBytes(); // Default encoding

            } else {

                throw new IIOInvalidTreeException("Empty comment node!", node);

            }

        }

    }

    /**

     * Returns the array encoded as a String, using ISO-Latin-1 encoding.

     * If an application needs another encoding, the data array must be

     * consulted directly.

     */

    String getComment() {

        try {

            return new String (data, ENCODING);

        } catch (UnsupportedEncodingException e) {}  // Won't happen

        return null;

    }

    /**

     * Returns an <code>IIOMetadataNode</code> containing the data array

     * as a user object and a string encoded using ISO-8895-1, as an

     * attribute.

     */

    IIOMetadataNode getNativeNode() {

        IIOMetadataNode node = new IIOMetadataNode("com");

        node.setAttribute("comment", getComment());

        if (data != null) {

            node.setUserObject(data.clone());

        }

        return node;

    }

    /**

     * Writes the data for this segment to the stream in

     * valid JPEG format, directly from the data array.

     */

    void write(ImageOutputStream ios) throws IOException {

        length = 2 + data.length;

        writeTag(ios);

        ios.write(data);

    }

    void print() {

        printTag("COM");

        System.out.println("<" + getComment() + ">");

    }

}