/*

 * Copyright 2003 Sun Microsystems, Inc.  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.  Sun designates this

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

 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package com.sun.imageio.plugins.wbmp;

import java.awt.Rectangle;

import java.awt.image.BufferedImage;

import java.awt.image.DataBufferByte;

import java.awt.image.MultiPixelPackedSampleModel;

import java.awt.image.Raster;

import java.awt.image.WritableRaster;

import javax.imageio.IIOException;

import javax.imageio.ImageReader;

import javax.imageio.ImageReadParam;

import javax.imageio.ImageTypeSpecifier;

import javax.imageio.metadata.IIOMetadata;

import javax.imageio.spi.ImageReaderSpi;

import javax.imageio.stream.ImageInputStream;

import java.io.*;

import java.util.ArrayList;

import java.util.Iterator;

import com.sun.imageio.plugins.common.I18N;

/** This class is the Java Image IO plugin reader for WBMP images.

 *  It may subsample the image, clip the image,

 *  and shift the decoded image origin if the proper decoding parameter

 *  are set in the provided <code>WBMPImageReadParam</code>.

 */

public class WBMPImageReader extends ImageReader {

    /** The input stream where reads from */

    private ImageInputStream iis = null;

    /** Indicates whether the header is read. */

    private boolean gotHeader = false;

    /** The original image width. */

    private int width;

    /** The original image height. */

    private int height;

    private int wbmpType;

    private WBMPMetadata metadata;

    /** Constructs <code>WBMPImageReader</code> from the provided

     *  <code>ImageReaderSpi</code>.

     */

    public WBMPImageReader(ImageReaderSpi originator) {

        super(originator);

    }

    /** Overrides the method defined in the superclass. */

    public void setInput(Object input,

                         boolean seekForwardOnly,

                         boolean ignoreMetadata) {

        super.setInput(input, seekForwardOnly, ignoreMetadata);

        iis = (ImageInputStream) input; // Always works

        gotHeader = false;

    }

    /** Overrides the method defined in the superclass. */

    public int getNumImages(boolean allowSearch) throws IOException {

        if (iis == null) {

            throw new IllegalStateException(I18N.getString("GetNumImages0"));

        }

        if (seekForwardOnly && allowSearch) {

            throw new IllegalStateException(I18N.getString("GetNumImages1"));

        }

        return 1;

    }

    public int getWidth(int imageIndex) throws IOException {

        checkIndex(imageIndex);

        readHeader();

        return width;

    }

    public int getHeight(int imageIndex) throws IOException {

        checkIndex(imageIndex);

        readHeader();

        return height;

    }

    public boolean isRandomAccessEasy(int imageIndex) throws IOException {

        checkIndex(imageIndex);

        return true;

    }

    private void checkIndex(int imageIndex) {

        if (imageIndex != 0) {

            throw new IndexOutOfBoundsException(I18N.getString("WBMPImageReader0"));

        }

    }

    public void readHeader() throws IOException {

        if (gotHeader)

            return;

        if (iis == null) {

            throw new IllegalStateException("Input source not set!");

        }

        metadata = new WBMPMetadata();

        wbmpType = iis.readByte();   // TypeField

        byte fixHeaderField = iis.readByte();

        // check for valid wbmp image

        if (fixHeaderField != 0

            || !isValidWbmpType(wbmpType))

        {

            throw new IIOException(I18N.getString("WBMPImageReader2"));

        }

        metadata.wbmpType = wbmpType;

        // Read image width

        width = readMultiByteInteger();

        metadata.width = width;

        // Read image height

        height = readMultiByteInteger();

        metadata.height = height;

        gotHeader = true;

    }

    public Iterator getImageTypes(int imageIndex)

        throws IOException {

        checkIndex(imageIndex);

        readHeader();

        BufferedImage bi =

            new BufferedImage(1, 1, BufferedImage.TYPE_BYTE_BINARY);

        ArrayList list = new ArrayList(1);

        list.add(new ImageTypeSpecifier(bi));

        return list.iterator();

    }

    public ImageReadParam getDefaultReadParam() {

        return new ImageReadParam();

    }

    public IIOMetadata getImageMetadata(int imageIndex)

        throws IOException {

        checkIndex(imageIndex);

        if (metadata == null) {

            readHeader();

        }

        return metadata;

    }

    public IIOMetadata getStreamMetadata() throws IOException {

        return null;

    }

    public BufferedImage read(int imageIndex, ImageReadParam param)

        throws IOException {

        if (iis == null) {

            throw new IllegalStateException(I18N.getString("WBMPImageReader1"));

        }

        checkIndex(imageIndex);

        clearAbortRequest();

        processImageStarted(imageIndex);

        if (param == null)

            param = getDefaultReadParam();

        //read header

        readHeader();

        Rectangle sourceRegion = new Rectangle(0, 0, 0, 0);

        Rectangle destinationRegion = new Rectangle(0, 0, 0, 0);

        computeRegions(param, this.width, this.height,

                       param.getDestination(),

                       sourceRegion,

                       destinationRegion);

        int scaleX = param.getSourceXSubsampling();

        int scaleY = param.getSourceYSubsampling();

        int xOffset = param.getSubsamplingXOffset();

        int yOffset = param.getSubsamplingYOffset();

        // If the destination is provided, then use it.  Otherwise, create new one

        BufferedImage bi = param.getDestination();

        if (bi == null)

            bi = new BufferedImage(destinationRegion.x + destinationRegion.width,

                              destinationRegion.y + destinationRegion.height,

                              BufferedImage.TYPE_BYTE_BINARY);

        boolean noTransform =

            destinationRegion.equals(new Rectangle(0, 0, width, height)) &&

            destinationRegion.equals(new Rectangle(0, 0, bi.getWidth(), bi.getHeight()));

        // Get the image data.

        WritableRaster tile = bi.getWritableTile(0, 0);

        // Get the SampleModel.

        MultiPixelPackedSampleModel sm =

            (MultiPixelPackedSampleModel)bi.getSampleModel();

        if (noTransform) {

            if (abortRequested()) {

                processReadAborted();

                return bi;

            }

            // If noTransform is necessary, read the data.

            iis.read(((DataBufferByte)tile.getDataBuffer()).getData(),

                     0, height*sm.getScanlineStride());

            processImageUpdate(bi,

                               0, 0,

                               width, height, 1, 1,

                               new int[]{0});

            processImageProgress(100.0F);

        } else {

            int len = (this.width + 7) / 8;

            byte[] buf = new byte[len];

            byte[] data = ((DataBufferByte)tile.getDataBuffer()).getData();

            int lineStride = sm.getScanlineStride();

            iis.skipBytes(len * sourceRegion.y);

            int skipLength = len * (scaleY - 1);

            // cache the values to avoid duplicated computation

            int[] srcOff = new int[destinationRegion.width];

            int[] destOff = new int[destinationRegion.width];

            int[] srcPos = new int[destinationRegion.width];

            int[] destPos = new int[destinationRegion.width];

            for (int i = destinationRegion.x, x = sourceRegion.x, j = 0;

                i < destinationRegion.x + destinationRegion.width;

                    i++, j++, x += scaleX) {

                srcPos[j] = x >> 3;

                srcOff[j] = 7 - (x & 7);

                destPos[j] = i >> 3;

                destOff[j] = 7 - (i & 7);

            }

            for (int j = 0, y = sourceRegion.y,

                k = destinationRegion.y * lineStride;

                j < destinationRegion.height; j++, y+=scaleY) {

                if (abortRequested())

                    break;

                iis.read(buf, 0, len);

                for (int i = 0; i < destinationRegion.width; i++) {

                    //get the bit and assign to the data buffer of the raster

                    int v = (buf[srcPos[i]] >> srcOff[i]) & 1;

                    data[k + destPos[i]] |= v << destOff[i];

                }

                k += lineStride;

                iis.skipBytes(skipLength);

                        processImageUpdate(bi,

                                           0, j,

                                           destinationRegion.width, 1, 1, 1,

                                           new int[]{0});

                        processImageProgress(100.0F*j/destinationRegion.height);

            }

        }

        if (abortRequested())

            processReadAborted();

        else

            processImageComplete();

        return bi;

    }

    public boolean canReadRaster() {

        return true;

    }

    public Raster readRaster(int imageIndex,

                             ImageReadParam param) throws IOException {

        BufferedImage bi = read(imageIndex, param);

        return bi.getData();

    }

    public void reset() {

        super.reset();

        iis = null;

        gotHeader = false;

    }

    private int readMultiByteInteger() throws IOException {

        int value = iis.readByte();

        int result = value & 0x7f;

        while((value & 0x80) == 0x80) {

            result <<= 7;

            value = iis.readByte();

            result |= (value & 0x7f);

        }

        return result;

    }

    /*

     * This method verifies that given byte is valid wbmp type marker.

     * At the moment only 0x0 marker is described by wbmp spec.

     */

    boolean isValidWbmpType(int type) {

        return type == 0;

    }

}