/**
* Set thumbnail data.
*
* Use this to embed an arbitrary JPEG image within this IFD. The
* data will be checked to ensure that it has a proper {@link
* PelJpegMarker::EOI} at the end. If not, then the length is
* adjusted until one if found. An {@link PelIfdException} might be
* thrown (depending on {@link Pel::$strict}) this case.
*
* @param PelDataWindow the thumbnail data.
*/
function setThumbnail(PelDataWindow $d)
{
$size = $d->getSize();
/* Now move backwards until we find the EOI JPEG marker. */
while ($d->getByte($size - 2) != 0xff || $d->getByte($size - 1) != PelJpegMarker::EOI) {
$size--;
}
if ($size != $d->getSize()) {
Pel::maybeThrow(new PelIfdException('Decrementing thumbnail size ' . 'to %d bytes', $size));
}
$this->thumb_data = $d->getClone(0, $size);
}
/**
* Test data to see if it could be a valid JPEG image.
*
* The function will only look at the first few bytes of the data,
* and try to determine if it could be a valid JPEG image based on
* those bytes. This means that the check is more like a heuristic
* than a rigorous check.
*
* @param PelDataWindow the bytes that will be checked.
*
* @return boolean true if the bytes look like the beginning of a
* JPEG image, false otherwise.
*
* @see PelTiff::isValid()
*/
static function isValid(PelDataWindow $d)
{
/* JPEG data is stored in big-endian format. */
$d->setByteOrder(PelConvert::BIG_ENDIAN);
for ($i = 0; $i < 7; $i++) {
if ($d->getByte($i) != 0xff) {
break;
}
}
return $d->getByte($i) == PelJpegMarker::SOI;
}
/**
* Load TIFF data.
*
* The data given will be parsed and an internal tree representation
* will be built. If the data cannot be parsed correctly, a {@link
* PelInvalidDataException} is thrown, explaining the problem.
*
* @param
* d
* PelDataWindow the data from which the object will be
* constructed. This should be valid TIFF data, coming either
* directly from a TIFF image or from the Exif data in a JPEG image.
*/
public function load(PelDataWindow $d)
{
Pel::debug('Parsing %d bytes of TIFF data...', $d->getSize());
/*
* There must be at least 8 bytes available: 2 bytes for the byte
* order, 2 bytes for the TIFF header, and 4 bytes for the offset
* to the first IFD.
*/
if ($d->getSize() < 8) {
throw new PelInvalidDataException('Expected at least 8 bytes of TIFF ' . 'data, found just %d bytes.', $d->getSize());
}
/* Byte order */
if ($d->strcmp(0, 'II')) {
Pel::debug('Found Intel byte order');
$d->setByteOrder(PelConvert::LITTLE_ENDIAN);
} elseif ($d->strcmp(0, 'MM')) {
Pel::debug('Found Motorola byte order');
$d->setByteOrder(PelConvert::BIG_ENDIAN);
} else {
throw new PelInvalidDataException('Unknown byte order found in TIFF ' . 'data: 0x%2X%2X', $d->getByte(0), $d->getByte(1));
}
/* Verify the TIFF header */
if ($d->getShort(2) != self::TIFF_HEADER) {
throw new PelInvalidDataException('Missing TIFF magic value.');
}
/* IFD 0 offset */
$offset = $d->getLong(4);
Pel::debug('First IFD at offset %d.', $offset);
if ($offset > 0) {
/*
* Parse the first IFD, this will automatically parse the
* following IFDs and any sub IFDs.
*/
$this->ifd = new PelIfd(PelIfd::IFD0);
$this->ifd->load($d, $offset);
}
}
function testReadBigIntegers()
{
$window = new PelDataWindow("‰«Íï", PelConvert::BIG_ENDIAN);
$this->assertEqual($window->getSize(), 4);
$this->assertEqual($window->getBytes(), "‰«Íï");
$this->assertEqual($window->getByte(0), 0x89);
$this->assertEqual($window->getByte(1), 0xab);
$this->assertEqual($window->getByte(2), 0xcd);
$this->assertEqual($window->getByte(3), 0xef);
$this->assertEqual($window->getShort(0), 0x89ab);
$this->assertEqual($window->getShort(1), 0xabcd);
$this->assertEqual($window->getShort(2), 0xcdef);
$this->assertEqual($window->getLong(0), 0x89abcdef);
$window->setByteOrder(PelConvert::LITTLE_ENDIAN);
$this->assertEqual($window->getSize(), 4);
$this->assertEqual($window->getBytes(), "‰«Íï");
$this->assertEqual($window->getByte(0), 0x89);
$this->assertEqual($window->getByte(1), 0xab);
$this->assertEqual($window->getByte(2), 0xcd);
$this->assertEqual($window->getByte(3), 0xef);
$this->assertEqual($window->getShort(0), 0xab89);
$this->assertEqual($window->getShort(1), 0xcdab);
$this->assertEqual($window->getShort(2), 0xefcd);
$this->assertEqual($window->getLong(0), 0xefcdab89);
}
