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File: src/Base64DotSlashOrdered.php

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File: src/Base64DotSlashOrdered.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: 3 years ago
Size: 2,784 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 Base64DotSlashOrdered
 * ./[0-9][A-Z][a-z]
 *
 * @package ParagonIE\ConstantTime
 */
abstract class Base64DotSlashOrdered extends Base64
{
   
/**
     * Uses bitwise operators instead of table-lookups to turn 6-bit integers
     * into 8-bit integers.
     *
     * Base64 character set:
     * [.-9] [A-Z] [a-z]
     * 0x2e-0x39, 0x41-0x5a, 0x61-0x7a
     *
     * @param int $src
     * @return int
     */
   
protected static function decode6Bits(int $src): int
   
{
       
$ret = -1;

       
// if ($src > 0x2d && $src < 0x3a) ret += $src - 0x2e + 1; // -45
       
$ret += (((0x2d - $src) & ($src - 0x3a)) >> 8) & ($src - 45);

       
// if ($src > 0x40 && $src < 0x5b) ret += $src - 0x41 + 12 + 1; // -52
       
$ret += (((0x40 - $src) & ($src - 0x5b)) >> 8) & ($src - 52);

       
// if ($src > 0x60 && $src < 0x7b) ret += $src - 0x61 + 38 + 1; // -58
       
$ret += (((0x60 - $src) & ($src - 0x7b)) >> 8) & ($src - 58);

        return
$ret;
    }

   
/**
     * Uses bitwise operators instead of table-lookups to turn 8-bit integers
     * into 6-bit integers.
     *
     * @param int $src
     * @return string
     */
   
protected static function encode6Bits(int $src): string
   
{
       
$src += 0x2e;

       
// if ($src > 0x39) $src += 0x41 - 0x3a; // 7
       
$src += ((0x39 - $src) >> 8) & 7;

       
// if ($src > 0x5a) $src += 0x61 - 0x5b; // 6
       
$src += ((0x5a - $src) >> 8) & 6;

        return \
pack('C', $src);
    }
}

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