1<?php 2declare(strict_types=1); 3namespace ParagonIE\ConstantTime; 4 5use TypeError; 6 7/** 8 * Copyright (c) 2016 - 2022 Paragon Initiative Enterprises. 9 * Copyright (c) 2014 Steve "Sc00bz" Thomas (steve at tobtu dot com) 10 * 11 * Permission is hereby granted, free of charge, to any person obtaining a copy 12 * of this software and associated documentation files (the "Software"), to deal 13 * in the Software without restriction, including without limitation the rights 14 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 15 * copies of the Software, and to permit persons to whom the Software is 16 * furnished to do so, subject to the following conditions: 17 * 18 * The above copyright notice and this permission notice shall be included in all 19 * copies or substantial portions of the Software. 20 * 21 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 22 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 23 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 24 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 25 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 26 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 27 * SOFTWARE. 28 */ 29 30/** 31 * Class Binary 32 * 33 * Binary string operators that don't choke on 34 * mbstring.func_overload 35 * 36 * @package ParagonIE\ConstantTime 37 */ 38abstract class Binary 39{ 40 /** 41 * Safe string length 42 * 43 * @ref mbstring.func_overload 44 * 45 * @param string $str 46 * @return int 47 */ 48 public static function safeStrlen(string $str): int 49 { 50 if (\function_exists('mb_strlen')) { 51 // mb_strlen in PHP 7.x can return false. 52 /** @psalm-suppress RedundantCast */ 53 return (int) \mb_strlen($str, '8bit'); 54 } else { 55 return \strlen($str); 56 } 57 } 58 59 /** 60 * Safe substring 61 * 62 * @ref mbstring.func_overload 63 * 64 * @staticvar boolean $exists 65 * @param string $str 66 * @param int $start 67 * @param ?int $length 68 * @return string 69 * 70 * @throws TypeError 71 */ 72 public static function safeSubstr( 73 string $str, 74 int $start = 0, 75 $length = null 76 ): string { 77 if ($length === 0) { 78 return ''; 79 } 80 if (\function_exists('mb_substr')) { 81 return \mb_substr($str, $start, $length, '8bit'); 82 } 83 // Unlike mb_substr(), substr() doesn't accept NULL for length 84 if ($length !== null) { 85 return \substr($str, $start, $length); 86 } else { 87 return \substr($str, $start); 88 } 89 } 90} 91