/*

 * Copyright (c) 2003, 2013, 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

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package com.sun.imageio.plugins.wbmp;

import java.util.Locale;

import javax.imageio.spi.ImageReaderSpi;

import javax.imageio.stream.ImageInputStream;

import javax.imageio.spi.IIORegistry;

import javax.imageio.spi.ServiceRegistry;

import java.io.IOException;

import javax.imageio.ImageReader;

import javax.imageio.IIOException;

import com.sun.imageio.plugins.common.ReaderUtil;

public class WBMPImageReaderSpi extends ImageReaderSpi {

    private static final int MAX_WBMP_WIDTH = 1024;

    private static final int MAX_WBMP_HEIGHT = 768;

    private static String [] writerSpiNames =

        {"com.sun.imageio.plugins.wbmp.WBMPImageWriterSpi"};

    private static String[] formatNames = {"wbmp", "WBMP"};

    private static String[] entensions = {"wbmp"};

    private static String[] mimeType = {"image/vnd.wap.wbmp"};

    private boolean registered = false;

    public WBMPImageReaderSpi() {

        super("Oracle Corporation",

              "1.0",

              formatNames,

              entensions,

              mimeType,

              "com.sun.imageio.plugins.wbmp.WBMPImageReader",

              new Class[] { ImageInputStream.class },

              writerSpiNames,

              true,

              null, null, null, null,

              true,

              WBMPMetadata.nativeMetadataFormatName,

              "com.sun.imageio.plugins.wbmp.WBMPMetadataFormat",

              null, null);

    }

    public void onRegistration(ServiceRegistry registry,

                               Class<?> category) {

        if (registered) {

            return;

        }

        registered = true;

    }

    public String getDescription(Locale locale) {

        return "Standard WBMP Image Reader";

    }

    public boolean canDecodeInput(Object source) throws IOException {

        if (!(source instanceof ImageInputStream)) {

            return false;

        }

        ImageInputStream stream = (ImageInputStream)source;

        stream.mark();

        try {

            int type = stream.readByte();   // TypeField

            int fixHeaderField = stream.readByte();

            // check WBMP "header"

            if (type != 0 || fixHeaderField != 0) {

                // while WBMP reader does not support ext WBMP headers

                return false;

            }

            int width = ReaderUtil.readMultiByteInteger(stream);

            int height = ReaderUtil.readMultiByteInteger(stream);

            // check image dimension

            if (width <= 0 || height <= 0) {

                return false;

            }

            long dataLength = stream.length();

            if (dataLength == -1) {

                // We can't verify that amount of data in the stream

                // corresponds to image dimension because we do not know

                // the length of the data stream.

                // Assuming that wbmp image are used for mobile devices,

                // let's introduce an upper limit for image dimension.

                // In case if exact amount of raster data is unknown,

                // let's reject images with dimension above the limit.

                return (width < MAX_WBMP_WIDTH) && (height < MAX_WBMP_HEIGHT);

            }

            dataLength -= stream.getStreamPosition();

            long scanSize = (width / 8) + ((width % 8) == 0 ? 0 : 1);

            return (dataLength == scanSize * height);

        } finally {

            stream.reset();

        }

    }

    public ImageReader createReaderInstance(Object extension)

        throws IIOException {

        return new WBMPImageReader(this);

    }

}