--- /dev/null
+<?php
+
+/**
+ * PEL: PHP Exif Library.
+ * A library with support for reading and
+ * writing all Exif headers in JPEG and TIFF images using PHP.
+ *
+ * Copyright (C) 2004, 2005, 2006, 2007 Martin Geisler.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program in the file COPYING; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301 USA
+ */
+
+namespace lsolesen\pel;
+
+/**
+ * Class for handling JPEG data.
+ *
+ * The {@link PelJpeg} class defined here provides an abstraction for
+ * dealing with a JPEG file. The file will be contain a number of
+ * sections containing some {@link PelJpegContent content} identified
+ * by a {@link PelJpegMarker marker}.
+ *
+ * The {@link getExif()} method is used get hold of the {@link
+ * PelJpegMarker::APP1 APP1} section which stores Exif data. So if
+ * the name of the JPEG file is stored in $filename, then one would
+ * get hold of the Exif data by saying:
+ *
+ * <code>
+ * $jpeg = new PelJpeg($filename);
+ * $exif = $jpeg->getExif();
+ * $tiff = $exif->getTiff();
+ * $ifd0 = $tiff->getIfd();
+ * $exif = $ifd0->getSubIfd(PelIfd::EXIF);
+ * $ifd1 = $ifd0->getNextIfd();
+ * </code>
+ *
+ * The $idf0 and $ifd1 variables will then be two {@link PelTiff TIFF}
+ * {@link PelIfd Image File Directories}, in which the data is stored
+ * under the keys found in {@link PelTag}.
+ *
+ * Should one have some image data (in the form of a {@link
+ * PelDataWindow}) of an unknown type, then the {@link
+ * PelJpeg::isValid()} function is handy: it will quickly test if the
+ * data could be valid JPEG data. The {@link PelTiff::isValid()}
+ * function does the same for TIFF images.
+ *
+ * @author Martin Geisler <mgeisler@users.sourceforge.net>
+ * @package PEL
+ */
+class PelJpeg
+{
+
+ /**
+ * The sections in the JPEG data.
+ *
+ * A JPEG file is built up as a sequence of sections, each section
+ * is identified with a {@link PelJpegMarker}. Some sections can
+ * occur more than once in the JPEG stream (the {@link
+ * PelJpegMarker::DQT DQT} and {@link PelJpegMarker::DHT DTH}
+ * markers for example) and so this is an array of ({@link
+ * PelJpegMarker}, {@link PelJpegContent}) pairs.
+ *
+ * The content can be either generic {@link PelJpegContent JPEG
+ * content} or {@link PelExif Exif data}.
+ *
+ * @var array
+ */
+ private $sections = array();
+
+ /**
+ * The JPEG image data.
+ *
+ * @var PelDataWindow
+ */
+ private $jpeg_data = null;
+
+ /**
+ * Construct a new JPEG object.
+ *
+ * The new object will be empty unless an argument is given from
+ * which it can initialize itself. This can either be the filename
+ * of a JPEG image, a {@link PelDataWindow} object or a PHP image
+ * resource handle.
+ *
+ * New Exif data (in the form of a {@link PelExif} object) can be
+ * inserted with the {@link setExif()} method:
+ *
+ * <code>
+ * $jpeg = new PelJpeg($data);
+ * // Create container for the Exif information:
+ * $exif = new PelExif();
+ * // Now Add a PelTiff object with a PelIfd object with one or more
+ * // PelEntry objects to $exif... Finally add $exif to $jpeg:
+ * $jpeg->setExif($exif);
+ * </code>
+ *
+ * @param
+ * mixed the data that this JPEG. This can either be a
+ * filename, a {@link PelDataWindow} object, or a PHP image resource
+ * handle.
+ */
+ public function __construct($data = false)
+ {
+ if ($data === false) {
+ return;
+ }
+
+ if (is_string($data)) {
+ Pel::debug('Initializing PelJpeg object from %s', $data);
+ $this->loadFile($data);
+ } elseif ($data instanceof PelDataWindow) {
+ Pel::debug('Initializing PelJpeg object from PelDataWindow.');
+ $this->load($data);
+ } elseif (is_resource($data) && get_resource_type($data) == 'gd') {
+ Pel::debug('Initializing PelJpeg object from image resource.');
+ $this->load(new PelDataWindow($data));
+ } else {
+ throw new PelInvalidArgumentException('Bad type for $data: %s', gettype($data));
+ }
+ }
+
+ /**
+ * JPEG sections start with 0xFF. The first byte that is not
+ * 0xFF is a marker (hopefully).
+ *
+ * @param PelDataWindow $d
+ *
+ * @return integer
+ */
+ protected static function getJpgSectionStart($d)
+ {
+ for ($i = 0; $i < 7; $i ++) {
+ if ($d->getByte($i) != 0xFF) {
+ break;
+ }
+ }
+ return $i;
+ }
+
+ /**
+ * 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.
+ */
+ public 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) {
+ $i = $this->getJpgSectionStart($d);
+
+ $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(0x00, $content);
+ }
+
+ /* Done with the loop. */
+ break;
+ }
+ }
+ }
+ } /* while ($d->getSize() > 0) */
+ }
+
+ /**
+ * Load data from a file into a JPEG object.
+ *
+ * @param
+ * string the filename. This must be a readable file.
+ */
+ public function loadFile($filename)
+ {
+ $this->load(new PelDataWindow(file_get_contents($filename)));
+ }
+
+ /**
+ * Set Exif data.
+ *
+ * Use this to set the Exif data in the image. This will overwrite
+ * any old Exif information in the image.
+ *
+ * @param
+ * PelExif the Exif data.
+ */
+ public function setExif(PelExif $exif)
+ {
+ $app0_offset = 1;
+ $app1_offset = - 1;
+
+ /* Search through all sections looking for APP0 or APP1. */
+ $sections_count = count($this->sections);
+ for ($i = 0; $i < $sections_count; $i ++) {
+ if (! empty($this->sections[$i][0])) {
+ if ($this->sections[$i][0] == PelJpegMarker::APP0) {
+ $app0_offset = $i;
+ } elseif ($this->sections[$i][0] == PelJpegMarker::APP1) {
+ $app1_offset = $i;
+ break;
+ }
+ }
+ }
+
+ /*
+ * Store the Exif data at the appropriate place, either where the
+ * old Exif data was stored ($app1_offset) or right after APP0
+ * ($app0_offset+1).
+ */
+ if ($app1_offset > 0) {
+ $this->sections[$app1_offset][1] = $exif;
+ } else {
+ $this->insertSection(PelJpegMarker::APP1, $exif, $app0_offset + 1);
+ }
+ }
+
+ /**
+ * Set ICC data.
+ *
+ * Use this to set the ICC data in the image. This will overwrite
+ * any old ICC information in the image.
+ *
+ * @param
+ * PelJpegContent the ICC data.
+ */
+ public function setICC(PelJpegContent $icc)
+ {
+ $app1_offset = 1;
+ $app2_offset = - 1;
+
+ /* Search through all sections looking for APP0 or APP1. */
+ $count_sections = count($this->sections);
+ for ($i = 0; $i < $count_sections; $i ++) {
+ if (! empty($this->sections[$i][0])) {
+ if ($this->sections[$i][0] == PelJpegMarker::APP1) {
+ $app1_offset = $i;
+ } elseif ($this->sections[$i][0] == PelJpegMarker::APP2) {
+ $app2_offset = $i;
+ break;
+ }
+ }
+ }
+
+ /*
+ * Store the Exif data at the appropriate place, either where the
+ * old Exif data was stored ($app1_offset) or right after APP0
+ * ($app0_offset+1).
+ */
+ if ($app2_offset > 0) {
+ $this->sections[$app1_offset][1] = $icc;
+ } else {
+ $this->insertSection(PelJpegMarker::APP2, $icc, $app1_offset + 1);
+ }
+ }
+
+ /**
+ * Get Exif data.
+ *
+ * Use this to get the @{link PelExif Exif data} stored.
+ *
+ * @return PelExif the Exif data found or null if the image has no
+ * Exif data.
+ */
+ public function getExif()
+ {
+ $exif = $this->getSection(PelJpegMarker::APP1);
+ if ($exif instanceof PelExif) {
+ return $exif;
+ }
+ return null;
+ }
+
+ /**
+ * Get ICC data.
+ *
+ * Use this to get the @{link PelJpegContent ICC data} stored.
+ *
+ * @return PelJpegContent the ICC data found or null if the image has no
+ * ICC data.
+ */
+ public function getICC()
+ {
+ $icc = $this->getSection(PelJpegMarker::APP2);
+ if ($icc instanceof PelJpegContent) {
+ return $icc;
+ }
+ return null;
+ }
+
+ /**
+ * Clear any Exif data.
+ *
+ * This method will only clear the first @{link PelJpegMarker::APP1}
+ * section found (there should normally be just one).
+ */
+ public function clearExif()
+ {
+ $sections_count = count($this->sections);
+ for ($i = 0; $i < $sections_count; $i ++) {
+ if ($this->sections[$i][0] == PelJpegMarker::APP1) {
+ unset($this->sections[$i]);
+ return;
+ }
+ }
+ }
+
+ /**
+ * Append a new section.
+ *
+ * Used only when loading an image. If it used again later, then the
+ * section will end up after the @{link PelJpegMarker::EOI EOI
+ * marker} and will probably not be useful.
+ *
+ * Please use @{link setExif()} instead if you intend to add Exif
+ * information to an image as that function will know the right
+ * place to insert the data.
+ *
+ * @param
+ * PelJpegMarker the marker identifying the new section.
+ *
+ * @param
+ * PelJpegContent the content of the new section.
+ */
+ public function appendSection($marker, PelJpegContent $content)
+ {
+ $this->sections[] = array(
+ $marker,
+ $content
+ );
+ }
+
+ /**
+ * Insert a new section.
+ *
+ * Please use @{link setExif()} instead if you intend to add Exif
+ * information to an image as that function will know the right
+ * place to insert the data.
+ *
+ * @param
+ * PelJpegMarker the marker for the new section.
+ *
+ * @param
+ * PelJpegContent the content of the new section.
+ *
+ * @param
+ * int the offset where the new section will be inserted ---
+ * use 0 to insert it at the very beginning, use 1 to insert it
+ * between sections 1 and 2, etc.
+ */
+ public function insertSection($marker, PelJpegContent $content, $offset)
+ {
+ array_splice($this->sections, $offset, 0, array(
+ array(
+ $marker,
+ $content
+ )
+ ));
+ }
+
+ /**
+ * Get a section corresponding to a particular marker.
+ *
+ * Please use the {@link getExif()} if you just need the Exif data.
+ *
+ * This will search through the sections of this JPEG object,
+ * looking for a section identified with the specified {@link
+ * PelJpegMarker marker}. The {@link PelJpegContent content} will
+ * then be returned. The optional argument can be used to skip over
+ * some of the sections. So if one is looking for the, say, third
+ * {@link PelJpegMarker::DHT DHT} section one would do:
+ *
+ * <code>
+ * $dht3 = $jpeg->getSection(PelJpegMarker::DHT, 2);
+ * </code>
+ *
+ * @param
+ * PelJpegMarker the marker identifying the section.
+ *
+ * @param
+ * int the number of sections to be skipped. This must be a
+ * non-negative integer.
+ *
+ * @return PelJpegContent the content found, or null if there is no
+ * content available.
+ */
+ public function getSection($marker, $skip = 0)
+ {
+ foreach ($this->sections as $s) {
+ if ($s[0] == $marker) {
+ if ($skip > 0) {
+ $skip --;
+ } else {
+ return $s[1];
+ }
+ }
+ }
+
+ return null;
+ }
+
+ /**
+ * Get all sections.
+ *
+ * @return array an array of ({@link PelJpegMarker}, {@link
+ * PelJpegContent}) pairs. Each pair is an array with the {@link
+ * PelJpegMarker} as the first element and the {@link
+ * PelJpegContent} as the second element, so the return type is an
+ * array of arrays.
+ *
+ * So to loop through all the sections in a given JPEG image do
+ * this:
+ *
+ * <code>
+ * foreach ($jpeg->getSections() as $section) {
+ * $marker = $section[0];
+ * $content = $section[1];
+ * // Use $marker and $content here.
+ * }
+ * </code>
+ *
+ * instead of this:
+ *
+ * <code>
+ * foreach ($jpeg->getSections() as $marker => $content) {
+ * // Does not work the way you would think...
+ * }
+ * </code>
+ *
+ * The problem is that there could be several sections with the same
+ * marker, and thus a simple associative array does not suffice.
+ */
+ public function getSections()
+ {
+ return $this->sections;
+ }
+
+ /**
+ * Turn this JPEG object into bytes.
+ *
+ * The bytes returned by this method is ready to be stored in a file
+ * as a valid JPEG image. Use the {@link saveFile()} convenience
+ * method to do this.
+ *
+ * @return string bytes representing this JPEG object, including all
+ * its sections and their associated data.
+ */
+ public function getBytes()
+ {
+ $bytes = '';
+
+ foreach ($this->sections as $section) {
+ $m = $section[0];
+ $c = $section[1];
+
+ /* Write the marker */
+ $bytes .= "\xFF" . PelJpegMarker::getBytes($m);
+ /* Skip over empty markers. */
+ if ($m == PelJpegMarker::SOI || $m == PelJpegMarker::EOI) {
+ continue;
+ }
+
+ $data = $c->getBytes();
+ $size = strlen($data) + 2;
+
+ $bytes .= PelConvert::shortToBytes($size, PelConvert::BIG_ENDIAN);
+ $bytes .= $data;
+
+ /* In case of SOS, we need to write the JPEG data. */
+ if ($m == PelJpegMarker::SOS) {
+ $bytes .= $this->jpeg_data->getBytes();
+ }
+ }
+
+ return $bytes;
+ }
+
+ /**
+ * Save the JPEG object as a JPEG image in a file.
+ *
+ * @param
+ * string the filename to save in. An existing file with the
+ * same name will be overwritten!
+ *
+ * @return integer|FALSE The number of bytes that were written to the
+ * file, or FALSE on failure.
+ */
+ public function saveFile($filename)
+ {
+ return file_put_contents($filename, $this->getBytes());
+ }
+
+ /**
+ * Make a string representation of this JPEG object.
+ *
+ * This is mainly usefull for debugging. It will show the structure
+ * of the image, and its sections.
+ *
+ * @return string debugging information about this JPEG object.
+ */
+ public function __toString()
+ {
+ $str = Pel::tra("Dumping JPEG data...\n");
+ $count_sections = count($this->sections);
+ for ($i = 0; $i < $count_sections; $i ++) {
+ $m = $this->sections[$i][0];
+ $c = $this->sections[$i][1];
+ $str .= Pel::fmt("Section %d (marker 0x%02X - %s):\n", $i, $m, PelJpegMarker::getName($m));
+ $str .= Pel::fmt(" Description: %s\n", PelJpegMarker::getDescription($m));
+
+ if ($m == PelJpegMarker::SOI || $m == PelJpegMarker::EOI) {
+ continue;
+ }
+
+ if ($c instanceof PelExif) {
+ $str .= Pel::tra(" Content : Exif data\n");
+ $str .= $c->__toString() . "\n";
+ } elseif ($c instanceof PelJpegComment) {
+ $str .= Pel::fmt(" Content : %s\n", $c->getValue());
+ } else {
+ $str .= Pel::tra(" Content : Unknown\n");
+ }
+ }
+
+ return $str;
+ }
+
+ /**
+ * 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()
+ */
+ public static function isValid(PelDataWindow $d)
+ {
+ /* JPEG data is stored in big-endian format. */
+ $d->setByteOrder(PelConvert::BIG_ENDIAN);
+
+ $i = self::getJpgSectionStart($d);
+
+ return $d->getByte($i) == PelJpegMarker::SOI;
+ }
+}
projects / yaffs-website / blobdiff