404-solution / includes / core / RegexHelperPreg.php

RegexHelperPreg.php in 404 Solution trunk, at includes/core/RegexHelperPreg.php

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1	<?php
2
3
4	if (!defined('ABSPATH')) {
5	exit;
6	}
7
8	/**
9	* preg-backed implementation of ABJ_404_Solution_RegexHelper.
10	*
11	* Use when the PHP mbstring extension is unavailable. Also used directly
12	* by callers that need PCRE regex semantics (\d, \w, lookarounds,
13	* delimiters) regardless of host mbstring availability - the regex
14	* methods auto-pick a delimiter and forward to preg_*.
15	*/
16	class ABJ_404_Solution_RegexHelperPreg extends ABJ_404_Solution_RegexHelper {
17
18	/** @var self\|null */
19	private static $instance = null;
20	/**
21	* Test seam: install or clear the cached singleton instance without
22	* private-field reflection. Pass null to reset between tests; pass a
23	* configured instance (or double) to install it (M105 singleton-reset seam).
24	*
25	* @param self\|null $instance
26	* @return void
27	*/
28	public static function setInstance($instance) {
29	self::$instance = $instance;
30	}
31
32
33	/**
34	* Candidate delimiter characters tried in order when wrapping a PCRE
35	* pattern. The first one that does not appear in the pattern wins.
36	*
37	* @var array<int, string>
38	*/
39	private $delimiterChars = array('`', '^', '\|', '~', '!', ';', ':', ',', '@', "'", '/');
40
41	public static function getInstance(): self {
42	if (self::$instance === null) {
43	self::$instance = new self();
44	}
45	return self::$instance;
46	}
47
48	/**
49	* @param array<int, string>\|null $regs
50	* @return bool\|int
51	*/
52	public function regexMatch(string $pattern, string $string, ?array &$regs = null) {
53	$delimiterA = "{";
54	$delimiterB = "}";
55	if (strpos($pattern, "}") !== false) {
56	$delimiterA = $delimiterB = $this->findADelimiter($pattern);
57	}
58	$regs = $regs ?? [];
59	return preg_match($delimiterA . $pattern . $delimiterB, $string, $regs);
60	}
61
62	/**
63	* @param array<int, string>\|null $regs
64	* @return bool\|int
65	*/
66	public function regexMatchi(string $pattern, string $string, ?array &$regs = null) {
67	$delimiterA = "{";
68	$delimiterB = "}";
69	if (strpos($pattern, "}") !== false) {
70	$delimiterA = $delimiterB = $this->findADelimiter($pattern);
71	}
72	$regs = $regs ?? [];
73	return preg_match($delimiterA . $pattern . $delimiterB . 'i', $string, $regs);
74	}
75
76	/** @return string\|null */
77	public function regexReplace($pattern, $replacement, $string) {
78	$delimiterA = "{";
79	$delimiterB = "}";
80	if (strpos($pattern, "}") !== false) {
81	$delimiterA = $delimiterB = $this->findADelimiter($pattern);
82	}
83	$replacementDelimiter = $this->findADelimiter($replacement);
84	$replacement = preg_replace($replacementDelimiter . '\\\\' . $replacementDelimiter, '\$', $replacement) ?? $replacement;
85	return preg_replace($delimiterA . $pattern . $delimiterB, $replacement, $string);
86	}
87
88	/**
89	* Pick a delimiter character that does not occur in $pattern so the
90	* pattern can be wrapped as PCRE input without conflicting.
91	*
92	* @param string $pattern
93	* @return string
94	*/
95	public function findADelimiter(string $pattern): string {
96	if ($pattern === '') {
97	return $this->delimiterChars[0];
98	}
99
100	foreach ($this->delimiterChars as $char) {
101	if ($char === '') { continue; }
102	$parts = explode($char, $pattern);
103	if (count($parts) === 1) {
104	return $char;
105	}
106	}
107
108	throw new Exception("I can't find a valid delimiter character to use for the regular expression: "
109	. esc_html($pattern));
110	}
111	}
112