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/*
* $Id$
* Copyright (C) 2001-2002 The Apache Software Foundation. All rights reserved.
* For details on use and redistribution please refer to the
* LICENSE file included with these sources.
*/
package org.apache.fop.image.analyser;
// Java
import java.io.BufferedInputStream;
import java.io.IOException;
// FOP
import org.apache.fop.image.FopImage;
import org.apache.fop.fo.FOUserAgent;
/**
* ImageReader object for TIFF image type.
*
* @author Pankaj Narula, Michael Lee
* @version $Id$
*/
public class TIFFReader implements ImageReader {
private static final int TIFF_SIG_LENGTH = 8;
/** @see org.apache.fop.image.analyser.ImageReader */
public FopImage.ImageInfo verifySignature(String uri, BufferedInputStream bis,
FOUserAgent ua) throws IOException {
byte[] header = getDefaultHeader(bis);
boolean supported = false;
// first 2 bytes = II (little endian encoding)
if (header[0] == (byte) 0x49 && header[1] == (byte) 0x49) {
// look for '42' in byte 3 and '0' in byte 4
if (header[2] == 42 && header[3] == 0) {
supported = true;
}
}
// first 2 bytes == MM (big endian encoding)
if (header[0] == (byte) 0x4D && header[1] == (byte) 0x4D) {
// look for '42' in byte 4 and '0' in byte 3
if (header[2] == 0 && header[3] == 42) {
supported = true;
}
}
if (supported) {
FopImage.ImageInfo info = getDimension(header);
info.mimeType = getMimeType();
return info;
} else {
return null;
}
}
/**
* Returns the MIME type supported by this implementation.
*
* @return The MIME type
*/
public String getMimeType() {
return "image/tiff";
}
private FopImage.ImageInfo getDimension(byte[] header) {
// currently not setting the width and height
// these are set again by the Jimi image reader.
// I suppose I'll do it one day to be complete. Or
// someone else will.
// Note: bytes 4,5,6,7 contain the byte offset in the stream of the first IFD block
/*
* //png is always big endian
* int byte1 = header[ 16 ] & 0xff;
* int byte2 = header[ 17 ] & 0xff;
* int byte3 = header[ 18 ] & 0xff;
* int byte4 = header[ 19 ] & 0xff;
* long l = ( long ) ( ( byte1 << 24 ) | ( byte2 << 16 ) |
* ( byte3 << 8 ) | byte4 );
* this.width = ( int ) ( l );
* byte1 = header[ 20 ] & 0xff;
* byte2 = header[ 21 ] & 0xff;
* byte3 = header[ 22 ] & 0xff;
* byte4 = header[ 23 ] & 0xff;
* l = ( long ) ( ( byte1 << 24 ) | ( byte2 << 16 ) | ( byte3 << 8 ) |
* byte4 );
* this.height = ( int ) ( l );
*/
FopImage.ImageInfo info = new FopImage.ImageInfo();
info.width = -1;
info.height = -1;
return info;
}
private byte[] getDefaultHeader(BufferedInputStream imageStream)
throws IOException {
byte[] header = new byte[TIFF_SIG_LENGTH];
try {
imageStream.mark(TIFF_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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