tiff.php

Bug tracker, and reporter.

<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to [e-mail] so we can send you a copy immediately.
 *
 * @package    Zend_Pdf
 * @copyright  Copyright (c) 2005-2008 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */


/** Zend_Pdf_Resource_Image */
require_once 'Zend/Pdf/Resource/Image.php';

/** Zend_Pdf_Exception */
require_once 'Zend/Pdf/Exception.php';

/** Zend_Pdf_Element_Numeric */
require_once 'Zend/Pdf/Element/Numeric.php';

/** Zend_Pdf_Element_Name */
require_once 'Zend/Pdf/Element/Name.php';


/**
 * TIFF image
 *
 * @package    Zend_Pdf
 * @copyright  Copyright (c) 2005-2008 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
class Zend_Pdf_Resource_Image_Tiff extends Zend_Pdf_Resource_Image
{
    const TIFF_FIELD_TYPE_BYTE=1;
    const TIFF_FIELD_TYPE_ASCII=2;
    const TIFF_FIELD_TYPE_SHORT=3;
    const TIFF_FIELD_TYPE_LONG=4;
    const TIFF_FIELD_TYPE_RATIONAL=5;

    const TIFF_TAG_IMAGE_WIDTH=256;
    const TIFF_TAG_IMAGE_LENGTH=257; //Height
    const TIFF_TAG_BITS_PER_SAMPLE=258;
    const TIFF_TAG_COMPRESSION=259;
    const TIFF_TAG_PHOTOMETRIC_INTERPRETATION=262;
    const TIFF_TAG_STRIP_OFFSETS=273;
    const TIFF_TAG_SAMPLES_PER_PIXEL=277;
    const TIFF_TAG_STRIP_BYTE_COUNTS=279;

    const TIFF_COMPRESSION_UNCOMPRESSED = 1;
    const TIFF_COMPRESSION_CCITT1D = 2;
    const TIFF_COMPRESSION_GROUP_3_FAX = 3;
    const TIFF_COMPRESSION_GROUP_4_FAX  = 4;
    const TIFF_COMPRESSION_LZW = 5;
    const TIFF_COMPRESSION_JPEG = 6;
    const TIFF_COMPRESSION_FLATE = 8;
    const TIFF_COMPRESSION_FLATE_OBSOLETE_CODE = 32946;
    const TIFF_COMPRESSION_PACKBITS = 32773;

    const TIFF_PHOTOMETRIC_INTERPRETATION_WHITE_IS_ZERO=0;
    const TIFF_PHOTOMETRIC_INTERPRETATION_BLACK_IS_ZERO=1;
    const TIFF_PHOTOMETRIC_INTERPRETATION_RGB=2;
    const TIFF_PHOTOMETRIC_INTERPRETATION_RGB_INDEXED=3;
    const TIFF_PHOTOMETRIC_INTERPRETATION_CMYK=5;
    const TIFF_PHOTOMETRIC_INTERPRETATION_YCBCR=6;
    const TIFF_PHOTOMETRIC_INTERPRETATION_CIELAB=8;

    protected $_width;
    protected $_height;
    protected $_imageProperties;
    protected $_endianType;
    protected $_fileSize;
    protected $_bitsPerSample;
    protected $_compression;
    protected $_filter;
    protected $_colorCode;
    protected $_whiteIsZero;
    protected $_blackIsZero;
    protected $_colorSpace;
    protected $_imageDataOffset;
    protected $_imageDataLength;

    const TIFF_ENDIAN_BIG=0;
    const TIFF_ENDIAN_LITTLE=1;

    const UNPACK_TYPE_BYTE=0;
    const UNPACK_TYPE_SHORT=1;
    const UNPACK_TYPE_LONG=2;
    const UNPACK_TYPE_RATIONAL=3;

    /**
     * Byte unpacking function
     *
     * Makes it possible to unpack bytes in one statement for enhanced logic readability.
     *
     * @param int $type
     * @param string $bytes
     * @throws Zend_Pdf_Exception
     */
    protected function unpackBytes($type, $bytes) {
        if(!isset($this->_endianType)) {
            throw new Zend_Pdf_Exception("The unpackBytes function can only be used after the endianness of the file is known");
        }
        switch($type) {
            case Zend_Pdf_Resource_Image_Tiff::UNPACK_TYPE_BYTE:
                $format = 'C';
                $unpacked = unpack($format, $bytes);
                return $unpacked[1];
                break;
            case Zend_Pdf_Resource_Image_Tiff::UNPACK_TYPE_SHORT:
                $format = ($this->_endianType == Zend_Pdf_Resource_Image_Tiff::TIFF_ENDIAN_LITTLE)?'v':'n';
                $unpacked = unpack($format, $bytes);
                return $unpacked[1];
                break;
            case Zend_Pdf_Resource_Image_Tiff::UNPACK_TYPE_LONG:
                $format = ($this->_endianType == Zend_Pdf_Resource_Image_Tiff::TIFF_ENDIAN_LITTLE)?'V':'N';
                $unpacked = unpack($format, $bytes);
                return $unpacked[1];
                break;
            case Zend_Pdf_Resource_Image_Tiff::UNPACK_TYPE_RATIONAL:
                $format = ($this->_endianType == Zend_Pdf_Resource_Image_Tiff::TIFF_ENDIAN_LITTLE)?'V2':'N2';
                $unpacked = unpack($format, $bytes);
                return ($unpacked[1]/$unpacked[2]);
                break;
        }
    }

    /**
     * Object constructor
     *
     * @param string $imageFileName
     * @throws Zend_Pdf_Exception
     */
    public function __construct($imageFileName)
    {
        if (($imageFile = @fopen($imageFileName, 'rb')) === false ) {
            throw new Zend_Pdf_Exception( "Can not open '$imageFileName' file for reading." );
        }

        $byteOrderIndicator = fread($imageFile, 2);
        if($byteOrderIndicator == 'II') {
            $this->_endianType = Zend_Pdf_Resource_Image_Tiff::TIFF_ENDIAN_LITTLE;
        } else if($byteOrderIndicator == 'MM') {
            $this->_endianType = Zend_Pdf_Resource_Image_Tiff::TIFF_ENDIAN_BIG;
        } else {
            throw new Zend_Pdf_Exception( "Not a tiff file or Tiff corrupt. No byte order indication found" );
        }

        $version = $this->unpackBytes(Zend_Pdf_Resource_Image_Tiff::UNPACK_TYPE_SHORT, fread($imageFile, 2));

        if($version != 42) {
            throw new Zend_Pdf_Exception( "Not a tiff file or Tiff corrupt. Incorrect version number." );
        }
        $ifdOffset = $this->unpackBytes(Zend_Pdf_Resource_Image_Tiff::UNPACK_TYPE_LONG, fread($imageFile, 4));

        $fileStats = fstat($imageFile);
        $this->_fileSize = $fileStats['size'];

        /*
         * Tiff files are stored as a series of Image File Directories (IFD) each direcctory
         * has a specific number of entries each 12 bytes in length. At the end of the directories
         * is four bytes pointing to the offset of the next IFD.
         */

        while($ifdOffset > 0) {
            if(fseek($imageFile, $ifdOffset, SEEK_SET) == -1 || $ifdOffset+2 >= $this->_fileSize) {
                throw new Zend_Pdf_Exception("Could not seek to the image file directory as indexed by the file. Likely cause is TIFF corruption. Offset: ". $ifdOffset);
            }

            $numDirEntries = $this->unpackBytes(Zend_Pdf_Resource_Image_Tiff::UNPACK_TYPE_SHORT, fread($imageFile, 2));

            /*
             * Since we now know how many entries are in this (IFD) we can extract the data.
             * The format of a TIFF directory entry is:
             *
             * 2 bytes (short) tag code; See TIFF_TAG constants at the top for supported values. (There are many more in the spec)
             * 2 bytes (short) field type
             * 4 bytes (long) number of values, or value count.
             * 4 bytes (mixed) data if the data will fit into 4 bytes or an offset if the data is too large.
             */
            for($dirEntryIdx = 1; $dirEntryIdx <= $numDirEntries; $dirEntryIdx++) {
                $tag         = $this->unpackBytes(Zend_Pdf_Resource_Image_Tiff::UNPACK_TYPE_SHORT, fread($imageFile, 2));
                $fieldType   = $this->unpackBytes(Zend_Pdf_Resource_Image_Tiff::UNPACK_TYPE_SHORT, fread($imageFile, 2));
                $valueCount  = $this->unpackBytes(Zend_Pdf_Resource_Image_Tiff::UNPACK_TYPE_LONG, fread($imageFile, 4));

                switch($fieldType) {
                    case Zend_Pdf_Resource_Image_Tiff::TIFF_FIELD_TYPE_BYTE:
                        $fieldLength = $valueCount;
                        break;
                    case Zend_Pdf_Resource_Image_Tiff::TIFF_FIELD_TYPE_ASCII:
                        $fieldLength = $valueCount;
                        break;
                    case Zend_Pdf_Resource_Image_Tiff::TIFF_FIELD_TYPE_SHORT:
                        $fieldLength = $valueCount * 2;
                        break;
                    case Zend_Pdf_Resource_Image_Tiff::TIFF_FIELD_TYPE_LONG:
                        $fieldLength = $valueCount * 4;
                        break;
                    case Zend_Pdf_Resource_Image_Tiff::TIFF_FIELD_TYPE_RATIONAL:
                        $fieldLength = $valueCount * 8;
                        break;
                    default:
                        $fieldLength = $valueCount;
                }

                $offsetBytes = fread($imageFile, 4);

                if($fieldLength <= 4) {