<?php

/**
 * Part of the Sentinel package.
 *
 * NOTICE OF LICENSE
 *
 * Licensed under the 3-clause BSD License.
 *
 * This source file is subject to the 3-clause BSD License that is
 * bundled with this package in the LICENSE file.
 *
 * @package    Sentinel
 * @version    2.0.13
 * @author     Cartalyst LLC
 * @license    BSD License (3-clause)
 * @copyright  (c) 2011-2016, Cartalyst LLC
 * @link       http://cartalyst.com
 */

namespace Cartalyst\Sentinel\Hashing;

trait Hasher
{
    /**
     * The salt length.
     *
     * @var int
     */
    protected $saltLength = 22;

    /**
     * Create a random string for a salt.
     *
     * @return string
     */
    protected function createSalt()
    {
        $pool = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ./';
        $max = strlen($pool) - 1;
        $salt = '';
        for ($i = 0; $i < $this->saltLength; ++$i) {
            $salt .= $pool[random_int(0, $max)];
        }
        return $salt;
    }

    /**
     * Compares two strings $a and $b in length-constant time.
     *
     * @param  string  $a
     * @param  string  $b
     * @return boolean
     */
    protected function slowEquals($a, $b)
    {
        $diff = strlen($a) ^ strlen($b);

        for ($i = 0; $i < strlen($a) && $i < strlen($b); $i++) {
            $diff |= ord($a[$i]) ^ ord($b[$i]);
        }

        return $diff === 0;
    }
}
