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/* ====================================================================
   Licensed to the Apache Software Foundation (ASF) under one or more
   contributor license agreements.  See the NOTICE file distributed with
   this work for additional information regarding copyright ownership.
   The ASF licenses this file to You under the Apache License, Version 2.0
   (the "License"); you may not use this file except in compliance with
   the License.  You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
==================================================================== */

package org.apache.poi.hslf.blip;

import java.awt.Dimension;
import java.awt.Rectangle;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.zip.InflaterInputStream;

import org.apache.poi.hslf.exceptions.HSLFException;
import org.apache.poi.util.LittleEndian;
import org.apache.poi.util.LocaleUtil;
import org.apache.poi.util.Units;

/**
 * Represents EMF (Windows Enhanced Metafile) picture data.
 */
public final class EMF extends Metafile {

    public static class NativeHeader {
        // rectangular inclusive-inclusive bounds, in device units, of the smallest 
        // rectangle that can be drawn around the image stored in the metafile.
        private final Rectangle deviceBounds;

        private final static String EMF_SIGNATURE = " EMF"; // 0x464D4520 (LE)
        
        public NativeHeader(byte data[], int offset) {
            int type = (int)LittleEndian.getUInt(data, offset); offset += 4;
            if (type != 1) {
                throw new HSLFException("Invalid EMF picture");
            }
            // ignore header size
            offset += 4;
            int left = LittleEndian.getInt(data, offset); offset += 4;
            int top = LittleEndian.getInt(data, offset); offset += 4;
            int right = LittleEndian.getInt(data, offset); offset += 4;
            int bottom = LittleEndian.getInt(data, offset); offset += 4;
            deviceBounds = new Rectangle(left, top, right-left, bottom-top);
            // ignore frame bounds
            offset += 16;
            String signature = new String(data, offset, EMF_SIGNATURE.length(), LocaleUtil.CHARSET_1252);
            if (!EMF_SIGNATURE.equals(signature)) {
                throw new HSLFException("Invalid EMF picture");
            }
        }

        public Dimension getSize() {
            return deviceBounds.getSize();
        }
    }
    
    @Override
    public byte[] getData(){
        try {
            byte[] rawdata = getRawData();

            ByteArrayOutputStream out = new ByteArrayOutputStream();
            InputStream is = new ByteArrayInputStream( rawdata );
            Header header = new Header();
            header.read(rawdata, CHECKSUM_SIZE);
            is.skip(header.getSize() + CHECKSUM_SIZE);

            InflaterInputStream inflater = new InflaterInputStream( is );
            byte[] chunk = new byte[4096];
            int count;
            while ((count = inflater.read(chunk)) >=0 ) {
                out.write(chunk,0,count);
            }
            inflater.close();
            return out.toByteArray();
        } catch (IOException e){
            throw new HSLFException(e);
        }
    }

    @Override
    public void setData(byte[] data) throws IOException {
        byte[] compressed = compress(data, 0, data.length);

        NativeHeader nHeader = new NativeHeader(data, 0);
        
        Header header = new Header();
        header.wmfsize = data.length;
        header.bounds = nHeader.deviceBounds;
        Dimension nDim = nHeader.getSize();
        header.size = new Dimension(Units.toEMU(nDim.getWidth()), Units.toEMU(nDim.getHeight()));
        header.zipsize = compressed.length;

        byte[] checksum = getChecksum(data);
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        out.write(checksum);
        if (uidInstanceCount == 2) {
            out.write(checksum);
        }
        header.write(out);
        out.write(compressed);

        setRawData(out.toByteArray());
    }

    @Override
    public PictureType getType(){
        return PictureType.EMF;
    }

    /**
     * EMF signature is {@code 0x3D40} or {@code 0x3D50}
     *
     * @return EMF signature ({@code 0x3D40} or {@code 0x3D50})
     */
    public int getSignature(){
        return (uidInstanceCount == 1 ? 0x3D40 : 0x3D50);
    }
    
    /**
     * Sets the EMF signature - either {@code 0x3D40} or {@code 0x3D50}
     */
    public void setSignature(int signature) {
        switch (signature) {
            case 0x3D40:
                uidInstanceCount = 1;
                break;
            case 0x3D50:
                uidInstanceCount = 2;
                break;
            default:
                throw new IllegalArgumentException(signature+" is not a valid instance/signature value for EMF");
        }        
    }
}