/**
* Load and parse Exif data.
*
* This will populate the object with Exif data, contained as a
* {@link PelTiff} object. This TIFF object can be accessed with
* the {@link getTiff()} method.
*
* @param PelDataWindow $d
*/
public function load(PelDataWindow $d)
{
Pel::debug('Parsing %d bytes of Exif data...', $d->getSize());
/* There must be at least 6 bytes for the Exif header. */
if ($d->getSize() < 6) {
throw new PelInvalidDataException('Expected at least 6 bytes of Exif ' . 'data, found just %d bytes.', $d->getSize());
}
/* Verify the Exif header */
if ($d->strcmp(0, self::EXIF_HEADER)) {
$d->setWindowStart(strlen(self::EXIF_HEADER));
} else {
throw new PelInvalidDataException('Exif header not found.');
}
/* The rest of the data is TIFF data. */
$this->tiff = new PelTiff();
$this->tiff->load($d);
}
/**
* Turn this directory into bytes.
*
* This directory will be turned into a byte string, with the
* specified byte order. The offsets will be calculated from the
* offset given.
*
* @param int the offset of the first byte of this directory.
*
* @param PelByteOrder the byte order that should be used when
* turning integers into bytes. This should be one of {@link
* PelConvert::LITTLE_ENDIAN} and {@link PelConvert::BIG_ENDIAN}.
*/
function getBytes($offset, $order)
{
$bytes = '';
$extra_bytes = '';
Pel::debug('Bytes from IDF will start at offset %d within Exif data', $offset);
$n = count($this->entries) + count($this->sub);
if ($this->thumb_data != null) {
/* We need two extra entries for the thumbnail offset and
* length. */
$n += 2;
}
$bytes .= PelConvert::shortToBytes($n, $order);
/* Initialize offset of extra data. This included the bytes
* preceding this IFD, the bytes needed for the count of entries,
* the entries themselves (and sub entries), the extra data in the
* entries, and the IFD link.
*/
$end = $offset + 2 + 12 * $n + 4;
foreach ($this->entries as $tag => $entry) {
/* Each entry is 12 bytes long. */
$bytes .= PelConvert::shortToBytes($entry->getTag(), $order);
$bytes .= PelConvert::shortToBytes($entry->getFormat(), $order);
$bytes .= PelConvert::longToBytes($entry->getComponents(), $order);
/*
* Size? If bigger than 4 bytes, the actual data is not in
* the entry but somewhere else.
*/
$data = $entry->getBytes($order);
$s = strlen($data);
if ($s > 4) {
Pel::debug('Data size %d too big, storing at offset %d instead.', $s, $end);
$bytes .= PelConvert::longToBytes($end, $order);
$extra_bytes .= $data;
$end += $s;
} else {
Pel::debug('Data size %d fits.', $s);
/* Copy data directly, pad with NULL bytes as necessary to
* fill out the four bytes available.*/
$bytes .= $data . str_repeat(chr(0), 4 - $s);
}
}
if ($this->thumb_data != null) {
Pel::debug('Appending %d bytes of thumbnail data at %d', $this->thumb_data->getSize(), $end);
// TODO: make PelEntry a class that can be constructed with
// arguments corresponding to the newt four lines.
$bytes .= PelConvert::shortToBytes(PelTag::JPEG_INTERCHANGE_FORMAT_LENGTH, $order);
$bytes .= PelConvert::shortToBytes(PelFormat::LONG, $order);
$bytes .= PelConvert::longToBytes(1, $order);
$bytes .= PelConvert::longToBytes($this->thumb_data->getSize(), $order);
$bytes .= PelConvert::shortToBytes(PelTag::JPEG_INTERCHANGE_FORMAT, $order);
$bytes .= PelConvert::shortToBytes(PelFormat::LONG, $order);
$bytes .= PelConvert::longToBytes(1, $order);
$bytes .= PelConvert::longToBytes($end, $order);
$extra_bytes .= $this->thumb_data->getBytes();
$end += $this->thumb_data->getSize();
}
/* Find bytes from sub IFDs. */
$sub_bytes = '';
foreach ($this->sub as $type => $sub) {
if ($type == PelIfd::EXIF) {
$tag = PelTag::EXIF_IFD_POINTER;
} elseif ($type == PelIfd::GPS) {
$tag = PelTag::GPS_INFO_IFD_POINTER;
} elseif ($type == PelIfd::INTEROPERABILITY) {
$tag = PelTag::INTEROPERABILITY_IFD_POINTER;
}
/* Make an aditional entry with the pointer. */
$bytes .= PelConvert::shortToBytes($tag, $order);
/* Next the format, which is always unsigned long. */
$bytes .= PelConvert::shortToBytes(PelFormat::LONG, $order);
/* There is only one component. */
$bytes .= PelConvert::longToBytes(1, $order);
$data = $sub->getBytes($end, $order);
$s = strlen($data);
$sub_bytes .= $data;
$bytes .= PelConvert::longToBytes($end, $order);
$end += $s;
}
/* Make link to next IFD, if any*/
if ($this->isLastIFD()) {
$link = 0;
} else {
$link = $end;
}
Pel::debug('Link to next IFD: %d', $link);
$bytes .= PelConvert::longtoBytes($link, $order);
$bytes .= $extra_bytes . $sub_bytes;
if (!$this->isLastIfd()) {
$bytes .= $this->next->getBytes($end, $order);
}
return $bytes;
}
/**
* Check if data is valid TIFF data.
*
* This will read just enough data from the data window to determine
* if the data could be a valid TIFF data. This means that the
* check is more like a heuristic than a rigorous check.
*
* @param PelDataWindow $d
* the bytes that will be examined.
*
* @return boolean true if the data looks like valid TIFF data,
* false otherwise.
*
* @see PelJpeg::isValid()
*/
public static function isValid(PelDataWindow $d)
{
/* First check that we have enough data. */
if ($d->getSize() < 8) {
return false;
}
/* Byte order */
if ($d->strcmp(0, 'II')) {
$d->setByteOrder(PelConvert::LITTLE_ENDIAN);
} elseif ($d->strcmp(0, 'MM')) {
Pel::debug('Found Motorola byte order');
$d->setByteOrder(PelConvert::BIG_ENDIAN);
} else {
return false;
}
/* Verify the TIFF header */
return $d->getShort(2) == self::TIFF_HEADER;
}
/**
* 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) */
}
setlocale(LC_ALL, '');
/* Load the required files. One would normally just require the
* PelJpeg.php file for dealing with JPEG images, but because this
* example can handle both JPEG and TIFF it loads the PelDataWindow
* class too. */
require_once dirname(__FILE__) . '/../PelDataWindow.php';
require_once dirname(__FILE__) . '/../PelJpeg.php';
require_once dirname(__FILE__) . '/../PelTiff.php';
/* Store the name of the script in $prog and remove this first part of
* the command line. */
$prog = array_shift($argv);
$error = false;
/* The next argument could be -d to signal debug mode where lots of
* extra information is printed out when the image is parsed. */
if (isset($argv[0]) && $argv[0] == '-d') {
Pel::$debug = true;
array_shift($argv);
}
/* The mandatory input filename. */
if (isset($argv[0])) {
$input = array_shift($argv);
} else {
$error = true;
}
/* The mandatory output filename. */
if (isset($argv[0])) {
$output = array_shift($argv);
} else {
$error = true;
}
/* Usage information is printed if an error was found in the command
/**
* Enable/disable debugging output.
*
* @param boolean $flag
* use true to enable debug output, false to
* diable.
*/
public static function setDebug($flag)
{
self::$debug = $flag;
}
/**
* Enable/disable debugging output.
*
* @param boolean $flag use true to enable debug output, false to
* diable.
*/
function setDebug($flag)
{
self::$debug = $flag;
}
