PHP Classes

File: src/Binary.php

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  Classes of Scott Arciszewski   PHP Constant Time String Encoding   src/Binary.php   Download  
File: src/Binary.php
Role: Class source
Content type: text/plain
Description: Class source
Class: PHP Constant Time String Encoding
Encode text without leaking context information
Author: By
Last change:
Date: 5 years ago
Size: 2,606 bytes
 

Contents

Class file image Download
<?php
declare(strict_types=1);
namespace
ParagonIE\ConstantTime;

/**
 * Copyright (c) 2016 - 2018 Paragon Initiative Enterprises.
 * Copyright (c) 2014 Steve "Sc00bz" Thomas (steve at tobtu dot com)
 *
 * 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.
 */

/**
 * Class Binary
 *
 * Binary string operators that don't choke on
 * mbstring.func_overload
 *
 * @package ParagonIE\ConstantTime
 */
abstract class Binary
{
   
/**
     * Safe string length
     *
     * @ref mbstring.func_overload
     *
     * @param string $str
     * @return int
     */
   
public static function safeStrlen(string $str): int
   
{
        if (\
function_exists('mb_strlen')) {
            return (int) \
mb_strlen($str, '8bit');
        } else {
            return (int) \
strlen($str);
        }
    }

   
/**
     * Safe substring
     *
     * @ref mbstring.func_overload
     *
     * @staticvar boolean $exists
     * @param string $str
     * @param int $start
     * @param int $length
     * @return string
     * @throws \TypeError
     */
   
public static function safeSubstr(
       
string $str,
       
int $start = 0,
       
$length = null
   
): string {
        if (
$length === 0) {
            return
'';
        }
        if (\
function_exists('mb_substr')) {
            return \
mb_substr($str, $start, $length, '8bit');
        }
       
// Unlike mb_substr(), substr() doesn't accept NULL for length
       
if ($length !== null) {
            return \
substr($str, $start, $length);
        } else {
            return \
substr($str, $start);
        }
    }
}