old-autovect-branch/libjava/classpath/gnu/javax/imageio/bmp/BMPFileHeader.java

   1 /* BMPFileHeader.java --
   2    Copyright (C)  2005  Free Software Foundation, Inc.
   3
   4 This file is part of GNU Classpath.
   5
   6 GNU Classpath is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Classpath is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Classpath; see the file COPYING.  If not, write to the
  18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19 02110-1301 USA.
  20
  21 Linking this library statically or dynamically with other modules is
  22 making a combined work based on this library.  Thus, the terms and
  23 conditions of the GNU General Public License cover the whole
  24 combination.
  25
  26 As a special exception, the copyright holders of this library give you
  27 permission to link this library with independent modules to produce an
  28 executable, regardless of the license terms of these independent
  29 modules, and to copy and distribute the resulting executable under
  30 terms of your choice, provided that you also meet, for each linked
  31 independent module, the terms and conditions of the license of that
  32 module.  An independent module is a module which is not derived from
  33 or based on this library.  If you modify this library, you may extend
  34 this exception to your version of the library, but you are not
  35 obligated to do so.  If you do not wish to do so, delete this
  36 exception statement from your version. */
  37
  38 package gnu.javax.imageio.bmp;
  39
  40 import java.io.IOException;
  41 import javax.imageio.stream.ImageInputStream;
  42 import java.io.OutputStream;
  43 import java.nio.ByteBuffer;
  44 import java.nio.ByteOrder;
  45
  46 public class BMPFileHeader {
  47     /** Header signature, always 'BM' */
  48     private final static short bfType = 0x424d;
  49
  50     /** Bitmap file size, in bytes. */
  51     private long bfSize;
  52
  53     /** Offset from the beginning of the file to the bitmap data */
  54     private long bfOffBits;
  55
  56     /** BITMAPFILEHEADER is 14 bytes */
  57     public static final int SIZE = 14;
  58
  59     /**
  60      * Creates the header from an input stream, which is not closed.
  61      * @throws IOException if an I/O error occured.
  62      * @throws BMPException if the header was invalid
  63      */
  64     public BMPFileHeader(ImageInputStream in) throws IOException, BMPException {
  65         byte[] data = new byte[SIZE];
  66
  67         if (in.read(data) != SIZE)
  68             throw new IOException("Couldn't read header.");
  69         ByteBuffer buf = ByteBuffer.wrap(data);
  70
  71         if(buf.getShort(0) != bfType)
  72             throw new BMPException("Not a BMP file.");
  73
  74         buf.order(ByteOrder.LITTLE_ENDIAN);
  75
  76         // get size (keep unsigned)
  77         bfSize = ((long)buf.getInt(2) & (0xFFFFFFFF));
  78
  79         // Two reserved shorts are here, and should be zero,
  80         // perhaps they should be tested to be zero, but I don't
  81         // feel this strictness is necessary.
  82
  83         bfOffBits = ((long)buf.getInt(10) & (0xFFFFFFFF));
  84     }
  85
  86     /**
  87      * Writes the header to an output stream, which is not closed or flushed.
  88      * @throws IOException if an I/O error occured.
  89      */
  90     public void write(OutputStream out) throws IOException {
  91         ByteBuffer buf = ByteBuffer.allocate(SIZE);
  92         buf.putShort(0, bfType); // ID
  93         buf.putInt(2, (int)(bfSize & (0xFFFFFFFF))); // size
  94         buf.putInt(6, 0); // 4 reserved bytes set to zero
  95         buf.putInt(2, (int)(bfOffBits & (0xFFFFFFFF))); // size
  96         out.write(buf.array());
  97     }
  98
  99     /**
 100      * Sets the file size
 101      */
 102     public void setSize(long size){
 103         bfSize = size;
 104     }
 105
 106     /**
 107      * Sets the bitmap offset within the file
 108      */
 109     public void setOffset(long offset){
 110         bfOffBits = offset;
 111     }
 112
 113     /**
 114      * Gets the file size
 115      */
 116     public long getSize(){
 117         return bfSize;
 118     }
 119
 120     /**
 121      * Gets the bitmap offset within the file
 122      */
 123     public long getOffset(){
 124         return bfOffBits;
 125     }
 126 }
 127
 128