<?php 
declare(strict_types=1); 
namespace ParagonIE\ConstantTime; 
 
/** 
 *  Copyright (c) 2016 - 2018 Paragon Initiative Enterprises. 
 *  Copyright (c) 2014 Steve "Sc00bz" Thomas (steve at tobtu dot com) 
 * 
 *  Permission is hereby granted, free of charge, to any person obtaining a copy 
 *  of this software and associated documentation files (the "Software"), to deal 
 *  in the Software without restriction, including without limitation the rights 
 *  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 
 *  copies of the Software, and to permit persons to whom the Software is 
 *  furnished to do so, subject to the following conditions: 
 * 
 *  The above copyright notice and this permission notice shall be included in all 
 *  copies or substantial portions of the Software. 
 * 
 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
 *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
 *  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
 *  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
 *  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 
 *  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 
 *  SOFTWARE. 
 */ 
 
/** 
 * Class Binary 
 * 
 * Binary string operators that don't choke on 
 * mbstring.func_overload 
 * 
 * @package ParagonIE\ConstantTime 
 */ 
abstract class Binary 
{ 
    /** 
     * Safe string length 
     * 
     * @ref mbstring.func_overload 
     * 
     * @param string $str 
     * @return int 
     */ 
    public static function safeStrlen(string $str): int 
    { 
        if (\function_exists('mb_strlen')) { 
            return (int) \mb_strlen($str, '8bit'); 
        } else { 
            return (int) \strlen($str); 
        } 
    } 
 
    /** 
     * Safe substring 
     * 
     * @ref mbstring.func_overload 
     * 
     * @staticvar boolean $exists 
     * @param string $str 
     * @param int $start 
     * @param int $length 
     * @return string 
     * @throws \TypeError 
     */ 
    public static function safeSubstr( 
        string $str, 
        int $start = 0, 
        $length = null 
    ): string { 
        if ($length === 0) { 
            return ''; 
        } 
        if (\function_exists('mb_substr')) { 
            return \mb_substr($str, $start, $length, '8bit'); 
        } 
        // Unlike mb_substr(), substr() doesn't accept NULL for length 
        if ($length !== null) { 
            return \substr($str, $start, $length); 
        } else { 
            return \substr($str, $start); 
        } 
    } 
} 
 
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