xref: /dokuwiki/vendor/paragonie/constant_time_encoding/src/Binary.php (revision 8e88a29b81301f78509349ab1152bb09c229123e) 
1<?php
2declare(strict_types=1);
3namespace ParagonIE\ConstantTime;
4
5use SensitiveParameter;
6use TypeError;
7use function strlen;
8use function substr;
9
10/**
11 *  Copyright (c) 2016 - 2022 Paragon Initiative Enterprises.
12 *  Copyright (c) 2014 Steve "Sc00bz" Thomas (steve at tobtu dot com)
13 *
14 *  Permission is hereby granted, free of charge, to any person obtaining a copy
15 *  of this software and associated documentation files (the "Software"), to deal
16 *  in the Software without restriction, including without limitation the rights
17 *  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
18 *  copies of the Software, and to permit persons to whom the Software is
19 *  furnished to do so, subject to the following conditions:
20 *
21 *  The above copyright notice and this permission notice shall be included in all
22 *  copies or substantial portions of the Software.
23 *
24 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
25 *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
26 *  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
27 *  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
28 *  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
29 *  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
30 *  SOFTWARE.
31 */
32
33/**
34 * Class Binary
35 *
36 * Binary string operators that don't choke on
37 * mbstring.func_overload
38 *
39 * @package ParagonIE\ConstantTime
40 */
41abstract class Binary
42{
43    /**
44     * Safe string length
45     *
46     * @ref mbstring.func_overload
47     *
48     * @param string $str
49     * @return int
50     */
51    public static function safeStrlen(
52        #[SensitiveParameter]
53        string $str
54    ): int {
55        return strlen($str);
56    }
57
58    /**
59     * Safe substring
60     *
61     * @ref mbstring.func_overload
62     *
63     * @staticvar boolean $exists
64     * @param string $str
65     * @param int $start
66     * @param ?int $length
67     * @return string
68     *
69     * @throws TypeError
70     */
71    public static function safeSubstr(
72        #[SensitiveParameter]
73        string $str,
74        int $start = 0,
75        ?int $length = null
76    ): string {
77        if ($length === 0) {
78            return '';
79        }
80        // Unlike mb_substr(), substr() doesn't accept NULL for length
81        if ($length !== null) {
82            return substr($str, $start, $length);
83        } else {
84            return substr($str, $start);
85        }
86    }
87}
88