<?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 Base32Hex
* [0-9][A-V]
*
* @package ParagonIE\ConstantTime
*/
abstract class Base32Hex extends Base32
{
/**
* Uses bitwise operators instead of table-lookups to turn 5-bit integers
* into 8-bit integers.
*
* @param int $src
* @return int
*/
protected static function decode5Bits(int $src): int
{
$ret = -1;
// if ($src > 0x30 && $src < 0x3a) ret += $src - 0x2e + 1; // -47
$ret += (((0x2f - $src) & ($src - 0x3a)) >> 8) & ($src - 47);
// if ($src > 0x60 && $src < 0x77) ret += $src - 0x61 + 10 + 1; // -86
$ret += (((0x60 - $src) & ($src - 0x77)) >> 8) & ($src - 86);
return $ret;
}
/**
* Uses bitwise operators instead of table-lookups to turn 5-bit integers
* into 8-bit integers.
*
* @param int $src
* @return int
*/
protected static function decode5BitsUpper(int $src): int
{
$ret = -1;
// if ($src > 0x30 && $src < 0x3a) ret += $src - 0x2e + 1; // -47
$ret += (((0x2f - $src) & ($src - 0x3a)) >> 8) & ($src - 47);
// if ($src > 0x40 && $src < 0x57) ret += $src - 0x41 + 10 + 1; // -54
$ret += (((0x40 - $src) & ($src - 0x57)) >> 8) & ($src - 54);
return $ret;
}
/**
* Uses bitwise operators instead of table-lookups to turn 8-bit integers
* into 5-bit integers.
*
* @param int $src
* @return string
*/
protected static function encode5Bits(int $src): string
{
$src += 0x30;
// if ($src > 0x39) $src += 0x61 - 0x3a; // 39
$src += ((0x39 - $src) >> 8) & 39;
return \pack('C', $src);
}
/**
* Uses bitwise operators instead of table-lookups to turn 8-bit integers
* into 5-bit integers.
*
* Uppercase variant.
*
* @param int $src
* @return string
*/
protected static function encode5BitsUpper(int $src): string
{
$src += 0x30;
// if ($src > 0x39) $src += 0x41 - 0x3a; // 7
$src += ((0x39 - $src) >> 8) & 7;
return \pack('C', $src);
}
}
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