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File Content: `PelJpeg.php`

<?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
 */

/**
 * 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
 */
namespace lsolesen\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
     */
    protected $sections = [];

    /**
     * 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 boolean|string|PelDataWindow|resource|\GDImage $data
     *            the data that this JPEG. This can either be a
     *            filename, a {@link PelDataWindow} object, or a PHP image resource
     *            handle.
     * @throws PelInvalidArgumentException
     */
    public function __construct($data = false)
    {
        if ($data !== false) {
            if (is_string($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') || (PHP_VERSION_ID >= 80000 && is_object($data) && $data instanceof \GDImage)) {
                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 $d
     *            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 $filename.
     *            This must be a readable file.
     * @return void
     * @throws PelException if file could not be loaded
     */
    public function loadFile($filename)
    {
        $content = @file_get_contents($filename);
        if ($content === false) {
            throw new PelException('Can not open file "%s"', $filename);
        } else {
            $this->load(new PelDataWindow($content));
        }
    }

    /**
     * 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 $exif
     *            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])) {
                $section = $this->sections[$i];
                if ($section[0] == PelJpegMarker::APP0) {
                    $app0_offset = $i;
                } elseif (($section[0] == PelJpegMarker::APP1) && ($section[1] instanceof PelExif)) {
                    $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 $icc
     *            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 first valid APP1 Exif section data.
     *
     * Use this to get the @{link PelExif Exif data} stored.
     *
     * @return PelExif|null the Exif data found or null if the image has no
     *         Exif data.
     */
    public function getExif()
    {
        $sections_count = count($this->sections);
        for ($i = 0; $i < $sections_count; $i ++) {
            $section = $this->getSection(PelJpegMarker::APP1, $i);
            if ($section instanceof PelExif) {
                return $section;
            }
        }
        return null;
    }

    /**
     * Get ICC data.
     *
     * Use this to get the @{link PelJpegContent ICC data} stored.
     *
     * @return PelJpegContent|null the ICC data found or null if the image has no
     *         ICC data.
     */
    public function getICC()
    {
        $icc = $this->getSection(PelJpegMarker::APP2);
        return $icc;
    }

    /**
     * Clear any Exif data.
     *
     * This method will only clear @{link PelJpegMarker::APP1} EXIF sections found.
     */
    public function clearExif()
    {
        $idx = 0;
        while ($idx < count($this->sections)) {
            $s = $this->sections[$idx];
            if (($s[0] == PelJpegMarker::APP1) && ($s[1] instanceof PelExif)) {
                array_splice($this->sections, $idx, 1);
                $idx --;
            } else {
                ++ $idx;
            }
        }
    }

    /**
     * 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 integer $marker
     *            the marker identifying the new section.
     * @param PelJpegContent $content
     *            the content of the new section.
     */
    public function appendSection($marker, PelJpegContent $content)
    {
        $this->sections[] = [
            $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 integer $marker
     *            the marker for the new section.
     * @param PelJpegContent $content
     *            the content of the new section.
     * @param integer $offset
     *            the offset where the new section will be inserted ---
     *            use 0 to insert it at the very beginning, use 1 to insert it
     *            between sections 1 and 2, etc.
     */
    public function insertSection($marker, PelJpegContent $content, $offset)
    {
        array_splice($this->sections, $offset, 0, [
            [
                $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 integer $marker
     *            the marker identifying the section.
     * @param integer $skip
     *            the number of sections to be skipped. This must be a
     *            non-negative integer.
     * @return PelJpegContent|PelExif|null the content found, or null if there is no
     *         content available.
     */
    public function getSection($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 $filename
     *            the filename to save in. An existing file with the
     *            same name will be overwritten!
     * @return integer|FALSE The number of bytes that were written to the
     *         file, or FALSE on failure.
     */
    public function saveFile($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 $d
     *            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;
    }
}
Name	Size	Permission
Pel.php	10753 bytes	0644
PelCanonMakerNotes.php	8958 bytes	0644
PelConvert.php	14173 bytes	0644
PelDataWindow.php	19433 bytes	0644
PelDataWindowOffsetException.php	1141 bytes	0644
PelDataWindowWindowException.php	1378 bytes	0644
PelEntry.php	7985 bytes	0644
PelEntryAscii.php	3793 bytes	0644
PelEntryByte.php	3039 bytes	0644
PelEntryCopyright.php	5324 bytes	0644
PelEntryException.php	2475 bytes	0644
PelEntryLong.php	4156 bytes	0644
PelEntryNumber.php	8694 bytes	0644
PelEntryRational.php	6221 bytes	0644
PelEntrySByte.php	3313 bytes	0644
PelEntrySLong.php	3429 bytes	0644
PelEntrySRational.php	5485 bytes	0644
PelEntrySShort.php	36714 bytes	0644
PelEntryShort.php	15184 bytes	0644
PelEntryTime.php	12303 bytes	0644
PelEntryUndefined.php	5621 bytes	0644
PelEntryUserComment.php	4104 bytes	0644
PelEntryVersion.php	5093 bytes	0644
PelEntryWindowsString.php	5663 bytes	0644
PelException.php	2044 bytes	0644
PelExif.php	4439 bytes	0644
PelFormat.php	6131 bytes	0644
PelIfd.php	56077 bytes	0644
PelIfdException.php	1426 bytes	0644
PelIllegalFormatException.php	1534 bytes	0644
PelInvalidArgumentException.php	1387 bytes	0644
PelInvalidDataException.php	1375 bytes	0644
PelJpeg.php	23082 bytes	0644
PelJpegComment.php	2762 bytes	0644
PelJpegContent.php	2262 bytes	0644
PelJpegInvalidMarkerException.php	1898 bytes	0644
PelJpegMarker.php	11789 bytes	0644
PelMakerNotes.php	2417 bytes	0644
PelMakerNotesMalformedException.php	1676 bytes	0644
PelOverflowException.php	2121 bytes	0644
PelTag.php	69462 bytes	0644
PelTiff.php	10078 bytes	0644
PelUnexpectedFormatException.php	2622 bytes	0644
PelWrongComponentCountException.php	2189 bytes	0644
File Content: PelJpeg.php

File Content: `PelJpeg.php`
