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/*
* Copyright 1999-2005 The Apache Software Foundation.
*
* Licensed 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.
*/
/* $Id$ */
package org.apache.fop.image.analyser;
// Java
import java.io.InputStream;
import java.io.IOException;
// FOP
import org.apache.fop.image.FopImage;
import org.apache.fop.apps.FOUserAgent;
/**
* ImageReader object for BMP image type.
*
* @author Pankaj Narula
* @version $Id: BMPReader.java,v 1.8 2003/03/06 21:25:45 jeremias Exp $
*/
public class BMPReader implements ImageReader {
/** Length of the BMP header */
protected static final int BMP_SIG_LENGTH = 46;
/** offset to width */
private static final int WIDTH_OFFSET = 18;
/** offset to height */
private static final int HEIGHT_OFFSET = 18;
/** offset to horizontal res */
private static final int HRES_OFFSET = 38;
/** offset to vertical res */
private static final int VRES_OFFSET = 42;
/** @see org.apache.fop.image.analyser.ImageReader */
public FopImage.ImageInfo verifySignature(String uri, InputStream bis,
FOUserAgent ua) throws IOException {
byte[] header = getDefaultHeader(bis);
boolean supported = ((header[0] == (byte) 0x42)
&& (header[1] == (byte) 0x4d));
if (supported) {
FopImage.ImageInfo info = getDimension(header);
info.inputStream = bis;
return info;
} else {
return null;
}
}
/**
* Returns the MIME type supported by this implementation.
*
* @return The MIME type
*/
public String getMimeType() {
return "image/bmp";
}
private FopImage.ImageInfo getDimension(byte[] header) {
FopImage.ImageInfo info = new FopImage.ImageInfo();
info.mimeType = getMimeType();
// little endian notation
int byte1 = header[WIDTH_OFFSET] & 0xff;
int byte2 = header[WIDTH_OFFSET + 1] & 0xff;
int byte3 = header[WIDTH_OFFSET + 2] & 0xff;
int byte4 = header[WIDTH_OFFSET + 3] & 0xff;
long l = (long) ((byte4 << 24) | (byte3 << 16)
| (byte2 << 8) | byte1);
info.width = (int) (l & 0xffffffff);
byte1 = header[HEIGHT_OFFSET] & 0xff;
byte2 = header[HEIGHT_OFFSET + 1] & 0xff;
byte3 = header[HEIGHT_OFFSET + 2] & 0xff;
byte4 = header[HEIGHT_OFFSET + 3] & 0xff;
l = (long) ((byte4 << 24) | (byte3 << 16) | (byte2 << 8) | byte1);
info.height = (int) (l & 0xffffffff);
byte1 = header[HRES_OFFSET] & 0xff;
byte2 = header[HRES_OFFSET + 1] & 0xff;
byte3 = header[HRES_OFFSET + 2] & 0xff;
byte4 = header[HRES_OFFSET + 3] & 0xff;
l = (long) ((byte4 << 24) | (byte3 << 16) | (byte2 << 8) | byte1);
if (l > 0) {
info.dpiHorizontal = l / 39.37d;
}
byte1 = header[VRES_OFFSET] & 0xff;
byte2 = header[VRES_OFFSET + 1] & 0xff;
byte3 = header[VRES_OFFSET + 2] & 0xff;
byte4 = header[VRES_OFFSET + 3] & 0xff;
l = (long) ((byte4 << 24) | (byte3 << 16) | (byte2 << 8) | byte1);
if (l > 0) {
info.dpiVertical = l / 39.37d;
}
return info;
}
private byte[] getDefaultHeader(InputStream imageStream)
throws IOException {
byte[] header = new byte[BMP_SIG_LENGTH];
try {
imageStream.mark(BMP_SIG_LENGTH + 1);
imageStream.read(header);
imageStream.reset();
} catch (IOException ex) {
try {
imageStream.reset();
} catch (IOException exbis) {
// throw the original exception, not this one
}
throw ex;
}
return header;
}
}
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