<?php 
/** 
 * Random_* Compatibility Library  
 * for using the new PHP 7 random_* API in PHP 5 projects 
 *  
 * The MIT License (MIT) 
 * 
 * Copyright (c) 2015 - 2017 Paragon Initiative Enterprises 
 *  
 * 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. 
 */ 
 
if (!is_callable('random_bytes')) { 
    /** 
     * If the libsodium PHP extension is loaded, we'll use it above any other 
     * solution. 
     * 
     * libsodium-php project: 
     * @ref https://github.com/jedisct1/libsodium-php 
     * 
     * @param int $bytes 
     * 
     * @throws Exception 
     * 
     * @return string 
     */ 
    function random_bytes($bytes) 
    { 
        try { 
            $bytes = RandomCompat_intval($bytes); 
        } catch (TypeError $ex) { 
            throw new TypeError( 
                'random_bytes(): $bytes must be an integer' 
            ); 
        } 
 
        if ($bytes < 1) { 
            throw new Error( 
                'Length must be greater than 0' 
            ); 
        } 
 
        /** 
         * @var string 
         */ 
        $buf = ''; 
 
        /** 
         * \Sodium\randombytes_buf() doesn't allow more than 2147483647 bytes to be 
         * generated in one invocation. 
         */ 
        if ($bytes > 2147483647) { 
            for ($i = 0; $i < $bytes; $i += 1073741824) { 
                $n = ($bytes - $i) > 1073741824 
                    ? 1073741824 
                    : $bytes - $i; 
                $buf .= Sodium::randombytes_buf($n); 
            } 
        } else { 
            $buf .= Sodium::randombytes_buf($bytes); 
        } 
 
        if (is_string($buf)) { 
            if (RandomCompat_strlen($buf) === $bytes) { 
                return $buf; 
            } 
        } 
 
        /** 
         * If we reach here, PHP has failed us. 
         */ 
        throw new Exception( 
            'Could not gather sufficient random data' 
        ); 
    } 
} 
 
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