<?php 
/** 
 * CodeIgniter 
 * 
 * An open source application development framework for PHP 
 * 
 * This content is released under the MIT License (MIT) 
 * 
 * Copyright (c) 2019 - 2022, CodeIgniter Foundation 
 * 
 * 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. 
 * 
 * @package    CodeIgniter 
 * @author    EllisLab Dev Team 
 * @copyright    Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/) 
 * @copyright    Copyright (c) 2014 - 2019, British Columbia Institute of Technology (https://bcit.ca/) 
 * @copyright    Copyright (c) 2019 - 2022, CodeIgniter Foundation (https://codeigniter.com/) 
 * @license    https://opensource.org/licenses/MIT    MIT License 
 * @link    https://codeigniter.com 
 * @since    Version 3.0.0 
 * @filesource 
 */ 
defined('BASEPATH') OR exit('No direct script access allowed'); 
 
/** 
 * PHP ext/hash compatibility package 
 * 
 * @package        CodeIgniter 
 * @subpackage    CodeIgniter 
 * @category    Compatibility 
 * @author        Andrey Andreev 
 * @link        https://codeigniter.com/userguide3/ 
 * @link        https://secure.php.net/hash 
 */ 
 
// ------------------------------------------------------------------------ 
 
if (is_php('5.6')) 
{ 
    return; 
} 
 
// ------------------------------------------------------------------------ 
 
if ( ! function_exists('hash_equals')) 
{ 
    /** 
     * hash_equals() 
     * 
     * @link    http://php.net/hash_equals 
     * @param    string    $known_string 
     * @param    string    $user_string 
     * @return    bool 
     */ 
    function hash_equals($known_string, $user_string) 
    { 
        if ( ! is_string($known_string)) 
        { 
            trigger_error('hash_equals(): Expected known_string to be a string, '.strtolower(gettype($known_string)).' given', E_USER_WARNING); 
            return FALSE; 
        } 
        elseif ( ! is_string($user_string)) 
        { 
            trigger_error('hash_equals(): Expected user_string to be a string, '.strtolower(gettype($user_string)).' given', E_USER_WARNING); 
            return FALSE; 
        } 
        elseif (($length = strlen($known_string)) !== strlen($user_string)) 
        { 
            return FALSE; 
        } 
 
        $diff = 0; 
        for ($i = 0; $i < $length; $i++) 
        { 
            $diff |= ord($known_string[$i]) ^ ord($user_string[$i]); 
        } 
 
        return ($diff === 0); 
    } 
} 
 
// ------------------------------------------------------------------------ 
 
if (is_php('5.5')) 
{ 
    return; 
} 
 
// ------------------------------------------------------------------------ 
 
if ( ! function_exists('hash_pbkdf2')) 
{ 
    /** 
     * hash_pbkdf2() 
     * 
     * @link    http://php.net/hash_pbkdf2 
     * @param    string    $algo 
     * @param    string    $password 
     * @param    string    $salt 
     * @param    int    $iterations 
     * @param    int    $length 
     * @param    bool    $raw_output 
     * @return    string 
     */ 
    function hash_pbkdf2($algo, $password, $salt, $iterations, $length = 0, $raw_output = FALSE) 
    { 
        if ( ! in_array(strtolower($algo), hash_algos(), TRUE)) 
        { 
            trigger_error('hash_pbkdf2(): Unknown hashing algorithm: '.$algo, E_USER_WARNING); 
            return FALSE; 
        } 
 
        if (($type = gettype($iterations)) !== 'integer') 
        { 
            if ($type === 'object' && method_exists($iterations, '__toString')) 
            { 
                $iterations = (string) $iterations; 
            } 
 
            if (is_string($iterations) && is_numeric($iterations)) 
            { 
                $iterations = (int) $iterations; 
            } 
            else 
            { 
                trigger_error('hash_pbkdf2() expects parameter 4 to be long, '.$type.' given', E_USER_WARNING); 
                return NULL; 
            } 
        } 
 
        if ($iterations < 1) 
        { 
            trigger_error('hash_pbkdf2(): Iterations must be a positive integer: '.$iterations, E_USER_WARNING); 
            return FALSE; 
        } 
 
        if (($type = gettype($length)) !== 'integer') 
        { 
            if ($type === 'object' && method_exists($length, '__toString')) 
            { 
                $length = (string) $length; 
            } 
 
            if (is_string($length) && is_numeric($length)) 
            { 
                $length = (int) $length; 
            } 
            else 
            { 
                trigger_error('hash_pbkdf2() expects parameter 5 to be long, '.$type.' given', E_USER_WARNING); 
                return NULL; 
            } 
        } 
 
        if ($length < 0) 
        { 
            trigger_error('hash_pbkdf2(): Length must be greater than or equal to 0: '.$length, E_USER_WARNING); 
            return FALSE; 
        } 
 
        $hash_length = defined('MB_OVERLOAD_STRING') 
            ? mb_strlen(hash($algo, NULL, TRUE), '8bit') 
            : strlen(hash($algo, NULL, TRUE)); 
        empty($length) && $length = $hash_length; 
 
        // Pre-hash password inputs longer than the algorithm's block size 
        // (i.e. prepare HMAC key) to mitigate potential DoS attacks. 
        static $block_sizes; 
        empty($block_sizes) && $block_sizes = array( 
            'gost' => 32, 
            'haval128,3' => 128, 
            'haval160,3' => 128, 
            'haval192,3' => 128, 
            'haval224,3' => 128, 
            'haval256,3' => 128, 
            'haval128,4' => 128, 
            'haval160,4' => 128, 
            'haval192,4' => 128, 
            'haval224,4' => 128, 
            'haval256,4' => 128, 
            'haval128,5' => 128, 
            'haval160,5' => 128, 
            'haval192,5' => 128, 
            'haval224,5' => 128, 
            'haval256,5' => 128, 
            'md2' => 16, 
            'md4' => 64, 
            'md5' => 64, 
            'ripemd128' => 64, 
            'ripemd160' => 64, 
            'ripemd256' => 64, 
            'ripemd320' => 64, 
            'salsa10' => 64, 
            'salsa20' => 64, 
            'sha1' => 64, 
            'sha224' => 64, 
            'sha256' => 64, 
            'sha384' => 128, 
            'sha512' => 128, 
            'snefru' => 32, 
            'snefru256' => 32, 
            'tiger128,3' => 64, 
            'tiger160,3' => 64, 
            'tiger192,3' => 64, 
            'tiger128,4' => 64, 
            'tiger160,4' => 64, 
            'tiger192,4' => 64, 
            'whirlpool' => 64 
        ); 
 
        if (isset($block_sizes[$algo], $password[$block_sizes[$algo]])) 
        { 
            $password = hash($algo, $password, TRUE); 
        } 
 
        $hash = ''; 
        // Note: Blocks are NOT 0-indexed 
        for ($bc = (int) ceil($length / $hash_length), $bi = 1; $bi <= $bc; $bi++) 
        { 
            $key = $derived_key = hash_hmac($algo, $salt.pack('N', $bi), $password, TRUE); 
            for ($i = 1; $i < $iterations; $i++) 
            { 
                $derived_key ^= $key = hash_hmac($algo, $key, $password, TRUE); 
            } 
 
            $hash .= $derived_key; 
        } 
 
        // This is not RFC-compatible, but we're aiming for natural PHP compatibility 
        if ( ! $raw_output) 
        { 
            $hash = bin2hex($hash); 
        } 
 
        return defined('MB_OVERLOAD_STRING') 
            ? mb_substr($hash, 0, $length, '8bit') 
            : substr($hash, 0, $length); 
    } 
} 
 
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