/**
* Load data into a JPEG object.
*
* The data supplied will be parsed and turned into an object
* structure representing the image. This structure can then be
* manipulated and later turned back into an string of bytes.
*
* This methods can be called at any time after a JPEG object has
* been constructed, also after the {@link appendSection()} has been
* called to append custom sections. Loading several JPEG images
* into one object will accumulate the sections, but there will only
* be one {@link PelJpegMarker::SOS} section at any given time.
*
* @param PelDataWindow the data that will be turned into JPEG
* sections.
*/
function load(PelDataWindow $d)
{
Pel::debug('Parsing %d bytes...', $d->getSize());
/* JPEG data is stored in big-endian format. */
$d->setByteOrder(PelConvert::BIG_ENDIAN);
/* Run through the data to read the sections in the image. After
* each section is read, the start of the data window will be
* moved forward, and after the last section we'll terminate with
* no data left in the window. */
while ($d->getSize() > 0) {
/* JPEG sections start with 0xFF. The first byte that is not
* 0xFF is a marker (hopefully).
*/
for ($i = 0; $i < 7; $i++) {
if ($d->getByte($i) != 0xff) {
break;
}
}
$marker = $d->getByte($i);
if (!PelJpegMarker::isValid($marker)) {
throw new PelJpegInvalidMarkerException($marker, $i);
}
/* Move window so first byte becomes first byte in this
* section. */
$d->setWindowStart($i + 1);
if ($marker == PelJpegMarker::SOI || $marker == PelJpegMarker::EOI) {
$content = new PelJpegContent(new PelDataWindow());
$this->appendSection($marker, $content);
} else {
/* Read the length of the section. The length includes the
* two bytes used to store the length. */
$len = $d->getShort(0) - 2;
Pel::debug('Found %s section of length %d', PelJpegMarker::getName($marker), $len);
/* Skip past the length. */
$d->setWindowStart(2);
if ($marker == PelJpegMarker::APP1) {
try {
$content = new PelExif();
$content->load($d->getClone(0, $len));
} catch (PelInvalidDataException $e) {
/* We store the data as normal JPEG content if it could
* not be parsed as Exif data. */
$content = new PelJpegContent($d->getClone(0, $len));
}
$this->appendSection($marker, $content);
/* Skip past the data. */
$d->setWindowStart($len);
} elseif ($marker == PelJpegMarker::COM) {
$content = new PelJpegComment();
$content->load($d->getClone(0, $len));
$this->appendSection($marker, $content);
$d->setWindowStart($len);
} else {
$content = new PelJpegContent($d->getClone(0, $len));
$this->appendSection($marker, $content);
/* Skip past the data. */
$d->setWindowStart($len);
/* In case of SOS, image data will follow. */
if ($marker == PelJpegMarker::SOS) {
/* Some images have some trailing (garbage?) following the
* EOI marker. To handle this we seek backwards until we
* find the EOI marker. Any trailing content is stored as
* a PelJpegContent object. */
$length = $d->getSize();
while ($d->getByte($length - 2) != 0xff || $d->getByte($length - 1) != PelJpegMarker::EOI) {
$length--;
}
$this->jpeg_data = $d->getClone(0, $length - 2);
Pel::debug('JPEG data: ' . $this->jpeg_data->__toString());
/* Append the EOI. */
$this->appendSection(PelJpegMarker::EOI, new PelJpegContent(new PelDataWindow()));
/* Now check to see if there are any trailing data. */
if ($length != $d->getSize()) {
Pel::maybeThrow(new PelException('Found trailing content ' . 'after EOI: %d bytes', $d->getSize() - $length));
$content = new PelJpegContent($d->getClone($length));
/* We don't have a proper JPEG marker for trailing
* garbage, so we just use 0x00... */
$this->appendSection(0x0, $content);
}
/* Done with the loop. */
break;
}
}
}
}
/* while ($d->getSize() > 0) */
}