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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: