1 /*
   2  * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package com.sun.imageio.plugins.wbmp;
  27 
  28 import java.util.Locale;
  29 import javax.imageio.spi.ImageReaderSpi;
  30 import javax.imageio.stream.ImageInputStream;
  31 import javax.imageio.spi.IIORegistry;
  32 import javax.imageio.spi.ServiceRegistry;
  33 import java.io.IOException;
  34 import javax.imageio.ImageReader;
  35 import javax.imageio.IIOException;
  36 import com.sun.imageio.plugins.common.ReaderUtil;
  37 
  38 public class WBMPImageReaderSpi extends ImageReaderSpi {
  39 
  40     private static final int MAX_WBMP_WIDTH = 1024;
  41     private static final int MAX_WBMP_HEIGHT = 768;
  42 
  43     private static String [] writerSpiNames =
  44         {"com.sun.imageio.plugins.wbmp.WBMPImageWriterSpi"};
  45     private static String[] formatNames = {"wbmp", "WBMP"};
  46     private static String[] entensions = {"wbmp"};
  47     private static String[] mimeType = {"image/vnd.wap.wbmp"};
  48 
  49     private boolean registered = false;
  50 
  51     public WBMPImageReaderSpi() {
  52         super("Oracle Corporation",
  53               "1.0",
  54               formatNames,
  55               entensions,
  56               mimeType,
  57               "com.sun.imageio.plugins.wbmp.WBMPImageReader",
  58               new Class<?>[] { ImageInputStream.class },
  59               writerSpiNames,
  60               true,
  61               null, null, null, null,
  62               true,
  63               WBMPMetadata.nativeMetadataFormatName,
  64               "com.sun.imageio.plugins.wbmp.WBMPMetadataFormat",
  65               null, null);
  66     }
  67 
  68     public void onRegistration(ServiceRegistry registry,
  69                                Class<?> category) {
  70         if (registered) {
  71             return;
  72         }
  73         registered = true;
  74     }
  75 
  76     public String getDescription(Locale locale) {
  77         return "Standard WBMP Image Reader";
  78     }
  79 
  80     public boolean canDecodeInput(Object source) throws IOException {
  81         if (!(source instanceof ImageInputStream)) {
  82             return false;
  83         }
  84 
  85         ImageInputStream stream = (ImageInputStream)source;
  86 
  87         stream.mark();
  88         try {
  89             int type = stream.readByte();   // TypeField
  90             int fixHeaderField = stream.readByte();
  91             // check WBMP "header"
  92             if (type != 0 || fixHeaderField != 0) {
  93                 // while WBMP reader does not support ext WBMP headers
  94                 return false;
  95             }
  96 
  97             int width = ReaderUtil.readMultiByteInteger(stream);
  98             int height = ReaderUtil.readMultiByteInteger(stream);
  99             // check image dimension
 100             if (width <= 0 || height <= 0) {
 101                 return false;
 102             }
 103 
 104             long dataLength = stream.length();
 105             if (dataLength == -1) {
 106                 // We can't verify that amount of data in the stream
 107                 // corresponds to image dimension because we do not know
 108                 // the length of the data stream.
 109                 // Assuming that wbmp image are used for mobile devices,
 110                 // let's introduce an upper limit for image dimension.
 111                 // In case if exact amount of raster data is unknown,
 112                 // let's reject images with dimension above the limit.
 113                 return (width < MAX_WBMP_WIDTH) && (height < MAX_WBMP_HEIGHT);
 114             }
 115 
 116             dataLength -= stream.getStreamPosition();
 117 
 118             long scanSize = (width / 8) + ((width % 8) == 0 ? 0 : 1);
 119 
 120             return (dataLength == scanSize * height);
 121         } finally {
 122             stream.reset();
 123         }
 124     }
 125 
 126     public ImageReader createReaderInstance(Object extension)
 127         throws IIOException {
 128         return new WBMPImageReader(this);
 129     }
 130 }