<?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')) {

    /**

     * Powered by ext/mcrypt (and thankfully NOT libmcrypt)

     *

     * @ref https://bugs.php.net/bug.php?id=55169

     * @ref https://github.com/php/php-src/blob/c568ffe5171d942161fc8dda066bce844bdef676/ext/mcrypt/mcrypt.c#L1321-L1386

     *

     * @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'

            );

        }

        $buf = @mcrypt_create_iv($bytes, MCRYPT_DEV_URANDOM);

        if (

            $buf !== false

            &&

            RandomCompat_strlen($buf) === $bytes

        ) {

            /**

             * Return our random entropy buffer here:

             */

            return $buf;

        }

        /**

         * If we reach here, PHP has failed us.

         */

        throw new Exception(

            'Could not gather sufficient random data'

        );

    }

}