1<?php
2/**
3 * @copyright Copyright (c) 2014 Carsten Brandt
4 * @license https://github.com/cebe/markdown/blob/master/LICENSE
5 * @link https://github.com/cebe/markdown#readme
6 */
7
8namespace cebe\markdown\inline;
9
10/**
11 * Adds inline emphasizes and strong elements
12 */
13trait EmphStrongTrait
14{
15	/**
16	 * Parses emphasized and strong elements.
17	 * @marker _
18	 * @marker *
19	 */
20	protected function parseEmphStrong($text)
21	{
22		$marker = $text[0];
23
24		if (!isset($text[1])) {
25			return [['text', $text[0]], 1];
26		}
27
28		if ($marker == $text[1]) { // strong
29			// work around a PHP bug that crashes with a segfault on too much regex backtrack
30			// check whether the end marker exists in the text
31			// https://github.com/erusev/parsedown/issues/443
32			// https://bugs.php.net/bug.php?id=45735
33			if (strpos($text, $marker . $marker, 2) === false) {
34				return [['text', $text[0] . $text[1]], 2];
35			}
36
37			if ($marker === '*' && preg_match('/^[*]{2}((?>\\\\[*]|[^*]|[*][^*]*[*])+?)[*]{2}/s', $text, $matches) ||
38				$marker === '_' && preg_match('/^__((?>\\\\_|[^_]|_[^_]*_)+?)__/us', $text, $matches)) {
39
40				return [
41					[
42						'strong',
43						$this->parseInline($matches[1]),
44					],
45					strlen($matches[0])
46				];
47			}
48		} else { // emph
49			// work around a PHP bug that crashes with a segfault on too much regex backtrack
50			// check whether the end marker exists in the text
51			// https://github.com/erusev/parsedown/issues/443
52			// https://bugs.php.net/bug.php?id=45735
53			if (strpos($text, $marker, 1) === false) {
54				return [['text', $text[0]], 1];
55			}
56
57			if ($marker === '*' && preg_match('/^[*]((?>\\\\[*]|[^*]|[*][*][^*]+?[*][*])+?)[*](?![*][^*])/s', $text, $matches) ||
58				$marker === '_' && preg_match('/^_((?>\\\\_|[^_]|__[^_]*__)+?)_(?!_[^_])\b/us', $text, $matches)) {
59				// if only a single whitespace or nothing is contained in an emphasis, do not consider it valid
60				if ($matches[1] === '' || $matches[1] === ' ') {
61					return [['text', $text[0]], 1];
62				}
63				return [
64					[
65						'emph',
66						$this->parseInline($matches[1]),
67					],
68					strlen($matches[0])
69				];
70			}
71		}
72		return [['text', $text[0]], 1];
73	}
74
75	protected function renderStrong($block)
76	{
77		return '<strong>' . $this->renderAbsy($block[1]) . '</strong>';
78	}
79
80	protected function renderEmph($block)
81	{
82		return '<em>' . $this->renderAbsy($block[1]) . '</em>';
83	}
84
85    abstract protected function parseInline($text);
86    abstract protected function renderAbsy($blocks);
87}
88