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mpdf/vendor/setasign/fpdi/src/PdfParser/CrossReference/LineReader.php

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+<?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).
+ *
+ * @package setasign\Fpdi\PdfParser\CrossReference
+ */
+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
+     */
+    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)
+    {
+        $cycles = -1;
+        $bytesPerCycle = 100;
+
+        $reader->reset(null, $bytesPerCycle);
+
+        while (
+            ($trailerPos = \strpos($reader->getBuffer(false), 'trailer', \max($bytesPerCycle * $cycles++, 0))) === false
+        ) {
+            if ($reader->increaseLength($bytesPerCycle) === false) {
+                break;
+            }
+        }
+
+        if ($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);
+        $linesCount = \count($lines);
+        $start = null;
+        $entryCount = 0;
+
+        $offsets = [];
+
+        /** @noinspection ForeachInvariantsInspection */
+        for ($i = 0; $i < $linesCount; $i++) {
+            $line = \trim($lines[$i]);
+            if ($line) {
+                $pieces = \explode(' ', $line);
+
+                $c = \count($pieces);
+                switch ($c) {
+                    case 2:
+                        $start = (int) $pieces[0];
+                        $entryCount += (int) $pieces[1];
+                        break;
+
+                    /** @noinspection PhpMissingBreakStatementInspection */
+                    case 3:
+                        switch ($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;
+    }
+}