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See Release Notes
Long Term Support Release

  • Bug fixes for general core bugs in 3.9.x will end* 10 May 2021 (12 months).
  • Bug fixes for security issues in 3.9.x will end* 8 May 2023 (36 months).
  • PHP version: minimum PHP 7.2.0 Note: minimum PHP version has increased since Moodle 3.8. PHP 7.3.x and 7.4.x are supported too.
<?php
>
/** * This file is part of FPDI * * @package setasign\Fpdi
< * @copyright Copyright (c) 2019 Setasign - Jan Slabon (https://www.setasign.com)
> * @copyright Copyright (c) 2020 Setasign GmbH & Co. KG (https://www.setasign.com)
* @license http://opensource.org/licenses/mit-license The MIT License */ namespace setasign\Fpdi\PdfParser\CrossReference; use setasign\Fpdi\PdfParser\PdfParser; use setasign\Fpdi\PdfParser\StreamReader; /** * Class FixedReader * * This reader allows a very less overhead parsing of single entries of the cross-reference, because the main entries * are only read when needed and not in a single run.
< * < * @package setasign\Fpdi\PdfParser\CrossReference
*/ class FixedReader extends AbstractReader implements ReaderInterface { /** * @var StreamReader */ protected $reader; /** * Data of subsections. * * @var array */ protected $subSections; /** * FixedReader constructor. * * @param PdfParser $parser * @throws CrossReferenceException */ public function __construct(PdfParser $parser) { $this->reader = $parser->getStreamReader(); $this->read(); parent::__construct($parser); } /** * Get all subsection data. * * @return array */ public function getSubSections() { return $this->subSections; } /** * @inheritdoc */ public function getOffsetFor($objectNumber) { foreach ($this->subSections as $offset => list($startObject, $objectCount)) {
> /** if ($objectNumber >= $startObject && $objectNumber < ($startObject + $objectCount)) { > * @var int $startObject $position = $offset + 20 * ($objectNumber - $startObject); > * @var int $objectCount $this->reader->ensure($position, 20); > */
$line = $this->reader->readBytes(20); if ($line[17] === 'f') { return false; } return (int) \substr($line, 0, 10); } } return false; } /** * Read the cross-reference. * * This reader will only read the subsections in this method. The offsets were resolved individually by this * information. * * @throws CrossReferenceException */ protected function read() { $subSections = []; $startObject = $entryCount = $lastLineStart = null; $validityChecked = false; while (($line = $this->reader->readLine(20)) !== false) { if (\strpos($line, 'trailer') !== false) { $this->reader->reset($lastLineStart); break; } // jump over if line content doesn't match the expected string if (\sscanf($line, '%d %d', $startObject, $entryCount) !== 2) { continue; } $oldPosition = $this->reader->getPosition(); $position = $oldPosition + $this->reader->getOffset(); if (!$validityChecked && $entryCount > 0) { $nextLine = $this->reader->readBytes(21); /* Check the next line for maximum of 20 bytes and not longer * By catching 21 bytes and trimming the length should be still 21. */ if (\strlen(\trim($nextLine)) !== 21) { throw new CrossReferenceException( 'Cross-reference entries are larger than 20 bytes.', CrossReferenceException::ENTRIES_TOO_LARGE ); } /* Check for less than 20 bytes: cut the line to 20 bytes and trim; have to result in exactly 18 bytes. * If it would have less bytes the substring would get the first bytes of the next line which would * evaluate to a 20 bytes long string after trimming. */ if (\strlen(\trim(\substr($nextLine, 0, 20))) !== 18) { throw new CrossReferenceException( 'Cross-reference entries are less than 20 bytes.', CrossReferenceException::ENTRIES_TOO_SHORT ); } $validityChecked = true; } $subSections[$position] = [$startObject, $entryCount]; $lastLineStart = $position + $entryCount * 20; $this->reader->reset($lastLineStart); } // reset after the last correct parsed line $this->reader->reset($lastLineStart); if (\count($subSections) === 0) { throw new CrossReferenceException( 'No entries found in cross-reference.', CrossReferenceException::NO_ENTRIES ); } $this->subSections = $subSections; } /** * Fixes an invalid object number shift. * * This method can be used to repair documents with an invalid subsection header: * * <code> * xref * 1 7 * 0000000000 65535 f * 0000000009 00000 n * 0000412075 00000 n * 0000412172 00000 n * 0000412359 00000 n * 0000412417 00000 n * 0000412468 00000 n * </code> * * It shall only be called on the first table. * * @return bool */ public function fixFaultySubSectionShift() { $subSections = $this->getSubSections(); if (\count($subSections) > 1) { return false; } $subSection = \current($subSections); if ($subSection[0] != 1) { return false; } if ($this->getOffsetFor(1) === false) { foreach ($subSections as $offset => list($startObject, $objectCount)) { $this->subSections[$offset] = [$startObject - 1, $objectCount]; } return true; } return false; } }