<?php 
/** 
 * Random_* Compatibility Library 
 * for using the new PHP 7 random_* API in PHP 5 projects 
 * 
 * @version 2.0.10 
 * @released 2017-03-13 
 * 
 * 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 (!defined('PHP_VERSION_ID')) { 
    // This constant was introduced in PHP 5.2.7 
    $RandomCompatversion = array_map('intval', explode('.', PHP_VERSION)); 
    define( 
        'PHP_VERSION_ID', 
        $RandomCompatversion[0] * 10000 
        + $RandomCompatversion[1] * 100 
        + $RandomCompatversion[2] 
    ); 
    $RandomCompatversion = null; 
} 
 
/** 
 * PHP 7.0.0 and newer have these functions natively. 
 */ 
if (PHP_VERSION_ID >= 70000) { 
    return; 
} 
 
if (!defined('RANDOM_COMPAT_READ_BUFFER')) { 
    define('RANDOM_COMPAT_READ_BUFFER', 8); 
} 
 
$RandomCompatDIR = dirname(__FILE__); 
 
require_once $RandomCompatDIR . '/byte_safe_strings.php'; 
require_once $RandomCompatDIR . '/cast_to_int.php'; 
require_once $RandomCompatDIR . '/error_polyfill.php'; 
 
if (!is_callable('random_bytes')) { 
    /** 
     * PHP 5.2.0 - 5.6.x way to implement random_bytes() 
     * 
     * We use conditional statements here to define the function in accordance 
     * to the operating environment. It's a micro-optimization. 
     * 
     * In order of preference: 
     *   1. Use libsodium if available. 
     *   2. fread() /dev/urandom if available (never on Windows) 
     *   3. mcrypt_create_iv($bytes, MCRYPT_DEV_URANDOM) 
     *   4. COM('CAPICOM.Utilities.1')->GetRandom() 
     * 
     * See RATIONALE.md for our reasoning behind this particular order 
     */ 
    if (extension_loaded('libsodium')) { 
        // See random_bytes_libsodium.php 
        if (PHP_VERSION_ID >= 50300 && is_callable('\\Sodium\\randombytes_buf')) { 
            require_once $RandomCompatDIR . '/random_bytes_libsodium.php'; 
        } elseif (method_exists('Sodium', 'randombytes_buf')) { 
            require_once $RandomCompatDIR . '/random_bytes_libsodium_legacy.php'; 
        } 
    } 
 
    /** 
     * Reading directly from /dev/urandom: 
     */ 
    if (DIRECTORY_SEPARATOR === '/') { 
        // DIRECTORY_SEPARATOR === '/' on Unix-like OSes -- this is a fast 
        // way to exclude Windows. 
        $RandomCompatUrandom = true; 
        $RandomCompat_basedir = ini_get('open_basedir'); 
 
        if (!empty($RandomCompat_basedir)) { 
            $RandomCompat_open_basedir = explode( 
                PATH_SEPARATOR, 
                strtolower($RandomCompat_basedir) 
            ); 
            $RandomCompatUrandom = (array() !== array_intersect( 
                array('/dev', '/dev/', '/dev/urandom'), 
                $RandomCompat_open_basedir 
            )); 
            $RandomCompat_open_basedir = null; 
        } 
 
        if ( 
            !is_callable('random_bytes') 
            && 
            $RandomCompatUrandom 
            && 
            @is_readable('/dev/urandom') 
        ) { 
            // Error suppression on is_readable() in case of an open_basedir 
            // or safe_mode failure. All we care about is whether or not we 
            // can read it at this point. If the PHP environment is going to 
            // panic over trying to see if the file can be read in the first 
            // place, that is not helpful to us here. 
 
            // See random_bytes_dev_urandom.php 
            require_once $RandomCompatDIR . '/random_bytes_dev_urandom.php'; 
        } 
        // Unset variables after use 
        $RandomCompat_basedir = null; 
    } else { 
        $RandomCompatUrandom = false; 
    } 
 
    /** 
     * mcrypt_create_iv() 
     * 
     * We only want to use mcypt_create_iv() if: 
     * 
     * - random_bytes() hasn't already been defined 
     * - the mcrypt extensions is loaded 
     * - One of these two conditions is true: 
     *   - We're on Windows (DIRECTORY_SEPARATOR !== '/') 
     *   - We're not on Windows and /dev/urandom is readabale 
     *     (i.e. we're not in a chroot jail) 
     * - Special case: 
     *   - If we're not on Windows, but the PHP version is between 
     *     5.6.10 and 5.6.12, we don't want to use mcrypt. It will 
     *     hang indefinitely. This is bad. 
     *   - If we're on Windows, we want to use PHP >= 5.3.7 or else 
     *     we get insufficient entropy errors. 
     */ 
    if ( 
        !is_callable('random_bytes') 
        && 
        // Windows on PHP < 5.3.7 is broken, but non-Windows is not known to be. 
        (DIRECTORY_SEPARATOR === '/' || PHP_VERSION_ID >= 50307) 
        && 
        // Prevent this code from hanging indefinitely on non-Windows; 
        // see https://bugs.php.net/bug.php?id=69833 
        ( 
            DIRECTORY_SEPARATOR !== '/' || 
            (PHP_VERSION_ID <= 50609 || PHP_VERSION_ID >= 50613) 
        ) 
        && 
        extension_loaded('mcrypt') 
    ) { 
        // See random_bytes_mcrypt.php 
        require_once $RandomCompatDIR . '/random_bytes_mcrypt.php'; 
    } 
    $RandomCompatUrandom = null; 
 
    /** 
     * This is a Windows-specific fallback, for when the mcrypt extension 
     * isn't loaded. 
     */ 
    if ( 
        !is_callable('random_bytes') 
        && 
        extension_loaded('com_dotnet') 
        && 
        class_exists('COM') 
    ) { 
        $RandomCompat_disabled_classes = preg_split( 
            '#\s*,\s*#', 
            strtolower(ini_get('disable_classes')) 
        ); 
 
        if (!in_array('com', $RandomCompat_disabled_classes)) { 
            try { 
                $RandomCompatCOMtest = new COM('CAPICOM.Utilities.1'); 
                if (method_exists($RandomCompatCOMtest, 'GetRandom')) { 
                    // See random_bytes_com_dotnet.php 
                    require_once $RandomCompatDIR . '/random_bytes_com_dotnet.php'; 
                } 
            } catch (com_exception $e) { 
                // Don't try to use it. 
            } 
        } 
        $RandomCompat_disabled_classes = null; 
        $RandomCompatCOMtest = null; 
    } 
 
    /** 
     * throw new Exception 
     */ 
    if (!is_callable('random_bytes')) { 
        /** 
         * We don't have any more options, so let's throw an exception right now 
         * and hope the developer won't let it fail silently. 
         * 
         * @param mixed $length 
         * @return void 
         * @throws Exception 
         */ 
        function random_bytes($length) 
        { 
            unset($length); // Suppress "variable not used" warnings. 
            throw new Exception( 
                'There is no suitable CSPRNG installed on your system' 
            ); 
        } 
    } 
} 
 
if (!is_callable('random_int')) { 
    require_once $RandomCompatDIR . '/random_int.php'; 
} 
 
$RandomCompatDIR = null; 
 
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