Search moodle.org's
Developer Documentation

See Release Notes

  • Bug fixes for general core bugs in 4.2.x will end 22 April 2024 (12 months).
  • Bug fixes for security issues in 4.2.x will end 7 October 2024 (18 months).
  • PHP version: minimum PHP 8.0.0 Note: minimum PHP version has increased since Moodle 4.1. PHP 8.1.x is supported too.
<?php

/**
 * This file is part of FPDI
 *
 * @package   setasign\Fpdi
 * @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 LineReader
 *
 * This reader class read all cross-reference entries in a single run.
 * It supports reading cross-references with e.g. invalid data (e.g. entries with a length < or > 20 bytes).
 */
class LineReader extends AbstractReader implements ReaderInterface
{
    /**
     * The object offsets.
     *
     * @var array
     */
    protected $offsets;

    /**
     * LineReader constructor.
     *
     * @param PdfParser $parser
     * @throws CrossReferenceException
     */
    public function __construct(PdfParser $parser)
    {
        $this->read($this->extract($parser->getStreamReader()));
        parent::__construct($parser);
    }

    /**
     * @inheritdoc
> * @return int|false
*/ public function getOffsetFor($objectNumber) { if (isset($this->offsets[$objectNumber])) { return $this->offsets[$objectNumber][0]; } return false; } /** * Get all found offsets. * * @return array */ public function getOffsets() { return $this->offsets; } /** * Extracts the cross reference data from the stream reader. * * @param StreamReader $reader * @return string * @throws CrossReferenceException */ protected function extract(StreamReader $reader) { $bytesPerCycle = 100; $reader->reset(null, $bytesPerCycle); $cycles = 0; do { // 6 = length of "trailer" - 1 $pos = \max(($bytesPerCycle * $cycles) - 6, 0); $trailerPos = \strpos($reader->getBuffer(false), 'trailer', $pos); $cycles++; } while ($trailerPos === false && $reader->increaseLength($bytesPerCycle) !== false); if ($trailerPos === false) { throw new CrossReferenceException( 'Unexpected end of cross reference. "trailer"-keyword not found.', CrossReferenceException::NO_TRAILER_FOUND ); } $xrefContent = \substr($reader->getBuffer(false), 0, $trailerPos); $reader->reset($reader->getPosition() + $trailerPos); return $xrefContent; } /** * Read the cross-reference entries. * * @param string $xrefContent * @throws CrossReferenceException */ protected function read($xrefContent) { // get eol markers in the first 100 bytes \preg_match_all("/(\r\n|\n|\r)/", \substr($xrefContent, 0, 100), $m); if (\count($m[0]) === 0) { throw new CrossReferenceException( 'No data found in cross-reference.', CrossReferenceException::INVALID_DATA ); } // count(array_count_values()) is faster then count(array_unique()) // @see https://github.com/symfony/symfony/pull/23731 // can be reverted for php7.2 $differentLineEndings = \count(\array_count_values($m[0])); if ($differentLineEndings > 1) { $lines = \preg_split("/(\r\n|\n|\r)/", $xrefContent, -1, PREG_SPLIT_NO_EMPTY); } else { $lines = \explode($m[0][0], $xrefContent); } unset($differentLineEndings, $m); if (!\is_array($lines)) { $this->offsets = []; return; } $start = 0; $offsets = []; // trim all lines and remove empty lines $lines = \array_filter(\array_map('\trim', $lines)); foreach ($lines as $line) { $pieces = \explode(' ', $line); switch (\count($pieces)) { case 2: $start = (int) $pieces[0]; break; case 3: switch ($pieces[2]) { case 'n': $offsets[$start] = [(int) $pieces[0], (int) $pieces[1]]; $start++; break 2; case 'f': $start++; break 2; } // fall through if pieces doesn't match default: throw new CrossReferenceException( \sprintf('Unexpected data in xref table (%s)', \implode(' ', $pieces)), CrossReferenceException::INVALID_DATA ); } } $this->offsets = $offsets; } }