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The JHOVE HUL validation modules.
/**********************************************************************
* Jhove - JSTOR/Harvard Object Validation Environment
* Copyright 2003 by JSTOR and the President and Fellows of Harvard College
**********************************************************************/
package edu.harvard.hul.ois.jhove.module.jpeg;
import java.io.*;
import java.util.*;
import edu.harvard.hul.ois.jhove.*;
import edu.harvard.hul.ois.jhove.module.tiff.ExifIFD;
import edu.harvard.hul.ois.jhove.module.tiff.TiffIFD;
import edu.harvard.hul.ois.jhove.module.tiff.TiffProfileExif;
import edu.harvard.hul.ois.jhove.module.tiff.TiffProfileExifIFD;
//import edu.harvard.hul.ois.jhove.module.*;
/**
* Reader of Exif data embedded in a JPEG App1 block. This makes use
* of the TIFF module, since an Exif stream is really an embedded TIFF
* file; but it is designed to fail cleanly if the TIFF module is absent.
*
* @author Gary McGath
*
*/
public final class JpegExif {
private boolean _exifProfileOK;
public JpegExif ()
{
_exifProfileOK = false;
}
/** Checks if the TIFF module is available.
*/
public static boolean isTiffAvailable ()
{
try {
Class tiffClass = Class.forName ("edu.harvard.hul.ois.jhove.module.TiffModule");
return true;
}
catch (Exception e) {
return false;
}
}
/** Reads the Exif data from the current point at the data stream,
* puts it into a temporary file, and makes a RepInfo object
* available. This should be called only if isTiffAvailable()
* has returned true.
*/
public RepInfo readExifData (DataInputStream dstream, JhoveBase je,
int length)
{
RandomAccessFile tiffRaf = null;
File tiffFile = null;
FileOutputStream fos = null;
RepInfo info = new RepInfo ("tempfile");
/* We're now at the beginning of the TIFF data.
* Copy it into a temporary file, then parse that
* as a TIFF file.
*/
try {
tiffFile = je.tempFile ();
}
catch (IOException e) {
info.setMessage (new ErrorMessage
("Error creating temporary file. Check your configuration: " +
e.getMessage ()));
return info;
}
try {
fos = new FileOutputStream (tiffFile);
int bufSize = je.getBufferSize ();
int tiffLen = length - 8;
/* Set a default buffer size if the app doesn't specify one. */
if (bufSize <= 0) {
bufSize = 32768;
}
if (bufSize > tiffLen) {
// can buffer whole file in one buffer
bufSize = tiffLen;
}
BufferedOutputStream bos = new BufferedOutputStream (fos, bufSize);
byte[] buf = new byte[bufSize];
while (tiffLen > 0) {
//int len;
int sz;
if (tiffLen < bufSize) {
sz = tiffLen;
}
else {
sz = bufSize;
}
sz = dstream.read (buf, 0, sz);
bos.write(buf, 0, sz);
tiffLen -= sz;
}
fos.flush ();
edu.harvard.hul.ois.jhove.module.TiffModule tiffMod =
new edu.harvard.hul.ois.jhove.module.TiffModule ();
tiffMod.setByteOffsetValid(true);
// Now parse the file, using a special parsing method.
// Close only after we're all done.
tiffRaf = new RandomAccessFile (tiffFile, "r");
List ifds = tiffMod.exifParse (tiffRaf, info);
if (ifds == null) {
return info;
}
// Locate the Exif IFD. (We probably also want the
// Interoperability IFD eventually.)
ListIterator iter = ifds.listIterator();
boolean first = true;
boolean haveNisoMetadata = false;
while (iter.hasNext()) {
Object ifd = iter.next ();
if (ifd instanceof TiffIFD) {
// The TIFF IFD has useful information, which gets put
// into its NISO metadata. Make it available to the caller.
if (first) {
NisoImageMetadata niso = ((TiffIFD) ifd).getNisoImageMetadata ();
// The first one is presumed to be the interesting one.
info.setProperty (new Property ("NisoImageMetadata",
PropertyType.NISOIMAGEMETADATA,
niso));
haveNisoMetadata = true;
TiffProfileExif exifProfile = new TiffProfileExif ();
_exifProfileOK = exifProfile.satisfiesProfile ((TiffIFD) ifd);
}
}
if (ifd instanceof ExifIFD) {
// Now for complicated stuff copying out the appropriate properties.
// Probably I just want to go through them and match interesting
// properties one by one, and copy them directly out.
// Or do I just want to copy the whole Exif property?
ExifIFD eifd = (ExifIFD) ifd;
Property ifdProp = eifd.getProperty( (je.getShowRawFlag ()));
List exifList = null;
if (ifdProp != null) {
exifList = eifd.exifProps (ifdProp);
}
if (_exifProfileOK) {
TiffProfileExifIFD exifIFDProfile = new TiffProfileExifIFD ();
_exifProfileOK = exifIFDProfile.satisfiesProfile(eifd);
}
if (exifList != null) {
info.setProperty(new Property ("Exif",
PropertyType.PROPERTY,
PropertyArity.LIST,
exifList));
}
// See if we have any interesting NISO metadata. If so, and
// we haven't gotten real NISO metadata, use it.
if (!haveNisoMetadata) {
NisoImageMetadata niso = eifd.getNisoImageMetadata ();
info.setProperty (new Property ("NisoImageMetadata",
PropertyType.NISOIMAGEMETADATA,
niso));
}
}
first = false;
}
}
catch (IOException e) {
info.setMessage (new ErrorMessage
("I/O exception processing Exif metadata: " +
e.getMessage ()));
// Maybe should put this directly in the parent's
// RepInfo, otherwise I have to copy the message afterwards.
}
finally {
if (tiffRaf != null) {
try {
tiffRaf.close();
}
catch (Exception e) {}
}
if (fos != null) {
try {
fos.close();
}
catch (Exception e) {}
}
if (tiffFile != null) {
try {
tiffFile.delete();
}
catch (Exception e) {}
}
}
return info;
}
/** Returns true if the Exif IFD is present and satisfies
* the profile requirements.
*/
public boolean isExifProfileOK ()
{
return _exifProfileOK;
}
}
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