formidable / classes / helpers / FrmSerializedStringParserHelper.php

FrmSerializedStringParserHelper.php in Formidable Forms – WordPress Form Builder for Contact Forms, Calculators, Quizzes & More 6.18, at classes/helpers/FrmSerializedStringParserHelper.php

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1	<?php
2
3	if ( ! defined( 'ABSPATH' ) ) {
4	die( 'You are not allowed to call this page directly.' );
5	}
6
7	/**
8	* Parses serialized strings without using the unsafe unserialize function.
9	*
10	* @since 6.2
11	*/
12	class FrmSerializedStringParserHelper {
13
14	/**
15	* @var FrmSerializedStringParserHelper\|null
16	*/
17	private static $instance;
18
19	/**
20	* Get a singleton instance of the parser.
21	*
22	* @return FrmSerializedStringParserHelper
23	*/
24	public static function get() {
25	if ( ! isset( self::$instance ) ) {
26	self::$instance = new self();
27	}
28	return self::$instance;
29	}
30
31	/**
32	* Private constructor to enforce the use of FrmSerializedStringParserHelper::get.
33	*/
34	private function __construct() {}
35
36	/**
37	* Parse a string containing a serialized data structure.
38	* This is the initial entry point into the recursive parser.
39	*
40	* @param string $string
41	* @return mixed
42	*/
43	public function parse( $string ) {
44	return $this->do_parse( new FrmStringReaderHelper( $string ) );
45	}
46
47	/**
48	* This is the recursive parser.
49	*
50	* @param FrmStringReaderHelper $string
51	* @return array\|bool\|float\|int\|string\|null
52	*/
53	private function do_parse( $string ) {
54	// May be : or ; as a terminator, depending on what the data type is.
55	$type = $string->read( 1 );
56	$string->skip_next_character();
57
58	switch ( $type ) {
59	case 'a':
60	return $this->parse_array( $string );
61
62	case 's':
63	return $this->parse_string( $string );
64
65	case 'i':
66	return $this->parse_int( $string );
67
68	case 'd':
69	return $this->parse_float( $string );
70
71	case 'b':
72	return $this->parse_bool( $string );
73	}
74
75	// Includes case 'N' and case 'O'.
76	// Treat a serialized object or anything unexpected as Null.
77	return null;
78	}
79
80	/**
81	* @param FrmStringReaderHelper $string
82	* @return array
83	*/
84	private function parse_array( $string ) {
85	// Associative array: a:length:{[index][value]...}
86	$count = (int) $string->read_until( ':' );
87
88	// Eat the opening "{" of the array.
89	$string->skip_next_character();
90
91	$val = array();
92	for ( $i = 0; $i < $count; $i++ ) {
93	$array_key = $this->do_parse( $string );
94	$array_value = $this->do_parse( $string );
95
96	if ( ! is_array( $array_key ) ) {
97	$val[ $array_key ] = $array_value;
98	}
99	}
100
101	// Eat "}" terminating the array.
102	$string->skip_next_character();
103
104	return $val;
105	}
106
107	/**
108	* @param FrmStringReaderHelper $string
109	* @return string
110	*/
111	private function parse_string( $string ) {
112	$len = (int) $string->read_until( ':' );
113	$val = $string->read( $len + 2 );
114
115	// Eat the separator.
116	$string->skip_next_character();
117
118	return $val;
119	}
120
121	/**
122	* @param FrmStringReaderHelper $string
123	* @return int
124	*/
125	private function parse_int( $string ) {
126	return (int) $string->read_until( ';' );
127	}
128
129	/**
130	* @param FrmStringReaderHelper $string
131	* @return float
132	*/
133	private function parse_float( $string ) {
134	return (float) $string->read_until( ';' );
135	}
136
137	/**
138	* @param FrmStringReaderHelper $string
139	* @return bool
140	*/
141	private function parse_bool( $string ) {
142	// Boolean is 0 or 1.
143	$val = $string->read( 1 ) === '1';
144	$string->skip_next_character();
145	return $val;
146	}
147	}
148