<?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 Base32
* [A-Z][2-7]
*
* @package ParagonIE\ConstantTime
*/
abstract class Base32 implements EncoderInterface
{
/**
* Decode a Base32-encoded string into raw binary
*
* @param string $src
* @return string
* @throws \TypeError
*/
public static function decode(string $src, bool $strictPadding = false): string
{
return static::doDecode($src, false, $strictPadding);
}
/**
* Decode an uppercase Base32-encoded string into raw binary
*
* @param string $src
* @return string
* @throws \TypeError
*/
public static function decodeUpper(string $src, bool $strictPadding = false): string
{
return static::doDecode($src, true, $strictPadding);
}
/**
* Encode into Base32 (RFC 4648)
*
* @param string $src
* @return string
* @throws \TypeError
*/
public static function encode(string $src): string
{
return static::doEncode($src, false, true);
}
/**
* Encode into Base32 (RFC 4648)
*
* @param string $src
* @return string
* @throws \TypeError
*/
public static function encodeUnpadded(string $src): string
{
return static::doEncode($src, false, false);
}
/**
* Encode into uppercase Base32 (RFC 4648)
*
* @param string $src
* @return string
* @throws \TypeError
*/
public static function encodeUpper(string $src): string
{
return static::doEncode($src, true, true);
}
/**
* Encode into uppercase Base32 (RFC 4648)
*
* @param string $src
* @return string
* @throws \TypeError
*/
public static function encodeUpperUnpadded(string $src): string
{
return static::doEncode($src, true, false);
}
/**
* 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 > 96 && $src < 123) $ret += $src - 97 + 1; // -64
$ret += (((0x60 - $src) & ($src - 0x7b)) >> 8) & ($src - 96);
// if ($src > 0x31 && $src < 0x38) $ret += $src - 24 + 1; // -23
$ret += (((0x31 - $src) & ($src - 0x38)) >> 8) & ($src - 23);
return $ret;
}
/**
* Uses bitwise operators instead of table-lookups to turn 5-bit integers
* into 8-bit integers.
*
* Uppercase variant.
*
* @param int $src
* @return int
*/
protected static function decode5BitsUpper(int $src): int
{
$ret = -1;
// if ($src > 64 && $src < 91) $ret += $src - 65 + 1; // -64
$ret += (((0x40 - $src) & ($src - 0x5b)) >> 8) & ($src - 64);
// if ($src > 0x31 && $src < 0x38) $ret += $src - 24 + 1; // -23
$ret += (((0x31 - $src) & ($src - 0x38)) >> 8) & ($src - 23);
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
{
$diff = 0x61;
// if ($src > 25) $ret -= 72;
$diff -= ((25 - $src) >> 8) & 73;
return \pack('C', $src + $diff);
}
/**
* 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
{
$diff = 0x41;
// if ($src > 25) $ret -= 40;
$diff -= ((25 - $src) >> 8) & 41;
return \pack('C', $src + $diff);
}
/**
* Base32 decoding
*
* @param string $src
* @param bool $upper
* @param bool $strictPadding
* @return string
* @throws \TypeError
* @psalm-suppress RedundantCondition
*/
protected static function doDecode(string $src, bool $upper = false, bool $strictPadding = false): string
{
// We do this to reduce code duplication:
$method = $upper
? 'decode5BitsUpper'
: 'decode5Bits';
// Remove padding
$srcLen = Binary::safeStrlen($src);
if ($srcLen === 0) {
return '';
}
if ($strictPadding) {
if (($srcLen & 7) === 0) {
for ($j = 0; $j < 7; ++$j) {
if ($src[$srcLen - 1] === '=') {
$srcLen--;
} else {
break;
}
}
}
if (($srcLen & 7) === 1) {
throw new \RangeException(
'Incorrect padding'
);
}
} else {
$src = \rtrim($src, '=');
$srcLen = Binary::safeStrlen($src);
}
$err = 0;
$dest = '';
// Main loop (no padding):
for ($i = 0; $i + 8 <= $srcLen; $i += 8) {
/** @var array<int, int> $chunk */
$chunk = \unpack('C*', Binary::safeSubstr($src, $i, 8));
/** @var int $c0 */
$c0 = static::$method($chunk[1]);
/** @var int $c1 */
$c1 = static::$method($chunk[2]);
/** @var int $c2 */
$c2 = static::$method($chunk[3]);
/** @var int $c3 */
$c3 = static::$method($chunk[4]);
/** @var int $c4 */
$c4 = static::$method($chunk[5]);
/** @var int $c5 */
$c5 = static::$method($chunk[6]);
/** @var int $c6 */
$c6 = static::$method($chunk[7]);
/** @var int $c7 */
$c7 = static::$method($chunk[8]);
$dest .= \pack(
'CCCCC',
(($c0 << 3) | ($c1 >> 2) ) & 0xff,
(($c1 << 6) | ($c2 << 1) | ($c3 >> 4)) & 0xff,
(($c3 << 4) | ($c4 >> 1) ) & 0xff,
(($c4 << 7) | ($c5 << 2) | ($c6 >> 3)) & 0xff,
(($c6 << 5) | ($c7 ) ) & 0xff
);
$err |= ($c0 | $c1 | $c2 | $c3 | $c4 | $c5 | $c6 | $c7) >> 8;
}
// The last chunk, which may have padding:
if ($i < $srcLen) {
/** @var array<int, int> $chunk */
$chunk = \unpack('C*', Binary::safeSubstr($src, $i, $srcLen - $i));
/** @var int $c0 */
$c0 = static::$method($chunk[1]);
if ($i + 6 < $srcLen) {
/** @var int $c1 */
$c1 = static::$method($chunk[2]);
/** @var int $c2 */
$c2 = static::$method($chunk[3]);
/** @var int $c3 */
$c3 = static::$method($chunk[4]);
/** @var int $c4 */
$c4 = static::$method($chunk[5]);
/** @var int $c5 */
$c5 = static::$method($chunk[6]);
/** @var int $c6 */
$c6 = static::$method($chunk[7]);
$dest .= \pack(
'CCCC',
(($c0 << 3) | ($c1 >> 2) ) & 0xff,
(($c1 << 6) | ($c2 << 1) | ($c3 >> 4)) & 0xff,
(($c3 << 4) | ($c4 >> 1) ) & 0xff,
(($c4 << 7) | ($c5 << 2) | ($c6 >> 3)) & 0xff
);
$err |= ($c0 | $c1 | $c2 | $c3 | $c4 | $c5 | $c6) >> 8;
} elseif ($i + 5 < $srcLen) {
/** @var int $c1 */
$c1 = static::$method($chunk[2]);
/** @var int $c2 */
$c2 = static::$method($chunk[3]);
/** @var int $c3 */
$c3 = static::$method($chunk[4]);
/** @var int $c4 */
$c4 = static::$method($chunk[5]);
/** @var int $c5 */
$c5 = static::$method($chunk[6]);
$dest .= \pack(
'CCCC',
(($c0 << 3) | ($c1 >> 2) ) & 0xff,
(($c1 << 6) | ($c2 << 1) | ($c3 >> 4)) & 0xff,
(($c3 << 4) | ($c4 >> 1) ) & 0xff,
(($c4 << 7) | ($c5 << 2) ) & 0xff
);
$err |= ($c0 | $c1 | $c2 | $c3 | $c4 | $c5) >> 8;
} elseif ($i + 4 < $srcLen) {
/** @var int $c1 */
$c1 = static::$method($chunk[2]);
/** @var int $c2 */
$c2 = static::$method($chunk[3]);
/** @var int $c3 */
$c3 = static::$method($chunk[4]);
/** @var int $c4 */
$c4 = static::$method($chunk[5]);
$dest .= \pack(
'CCC',
(($c0 << 3) | ($c1 >> 2) ) & 0xff,
(($c1 << 6) | ($c2 << 1) | ($c3 >> 4)) & 0xff,
(($c3 << 4) | ($c4 >> 1) ) & 0xff
);
$err |= ($c0 | $c1 | $c2 | $c3 | $c4) >> 8;
} elseif ($i + 3 < $srcLen) {
/** @var int $c1 */
$c1 = static::$method($chunk[2]);
/** @var int $c2 */
$c2 = static::$method($chunk[3]);
/** @var int $c3 */
$c3 = static::$method($chunk[4]);
$dest .= \pack(
'CC',
(($c0 << 3) | ($c1 >> 2) ) & 0xff,
(($c1 << 6) | ($c2 << 1) | ($c3 >> 4)) & 0xff
);
$err |= ($c0 | $c1 | $c2 | $c3) >> 8;
} elseif ($i + 2 < $srcLen) {
/** @var int $c1 */
$c1 = static::$method($chunk[2]);
/** @var int $c2 */
$c2 = static::$method($chunk[3]);
$dest .= \pack(
'CC',
(($c0 << 3) | ($c1 >> 2) ) & 0xff,
(($c1 << 6) | ($c2 << 1) ) & 0xff
);
$err |= ($c0 | $c1 | $c2) >> 8;
} elseif ($i + 1 < $srcLen) {
/** @var int $c1 */
$c1 = static::$method($chunk[2]);
$dest .= \pack(
'C',
(($c0 << 3) | ($c1 >> 2) ) & 0xff
);
$err |= ($c0 | $c1) >> 8;
} else {
$dest .= \pack(
'C',
(($c0 << 3) ) & 0xff
);
$err |= ($c0) >> 8;
}
}
/** @var bool $check */
$check = ($err === 0);
if (!$check) {
throw new \RangeException(
'Base32::doDecode() only expects characters in the correct base32 alphabet'
);
}
return $dest;
}
/**
* Base32 Encoding
*
* @param string $src
* @param bool $upper
* @param bool $pad
* @return string
* @throws \TypeError
*/
protected static function doEncode(string $src, bool $upper = false, $pad = true): string
{
// We do this to reduce code duplication:
$method = $upper
? 'encode5BitsUpper'
: 'encode5Bits';
$dest = '';
$srcLen = Binary::safeStrlen($src);
// Main loop (no padding):
for ($i = 0; $i + 5 <= $srcLen; $i += 5) {
/** @var array<int, int> $chunk */
$chunk = \unpack('C*', Binary::safeSubstr($src, $i, 5));
$b0 = $chunk[1];
$b1 = $chunk[2];
$b2 = $chunk[3];
$b3 = $chunk[4];
$b4 = $chunk[5];
$dest .=
static::$method( ($b0 >> 3) & 31) .
static::$method((($b0 << 2) | ($b1 >> 6)) & 31) .
static::$method((($b1 >> 1) ) & 31) .
static::$method((($b1 << 4) | ($b2 >> 4)) & 31) .
static::$method((($b2 << 1) | ($b3 >> 7)) & 31) .
static::$method((($b3 >> 2) ) & 31) .
static::$method((($b3 << 3) | ($b4 >> 5)) & 31) .
static::$method( $b4 & 31);
}
// The last chunk, which may have padding:
if ($i < $srcLen) {
/** @var array<int, int> $chunk */
$chunk = \unpack('C*', Binary::safeSubstr($src, $i, $srcLen - $i));
$b0 = $chunk[1];
if ($i + 3 < $srcLen) {
$b1 = $chunk[2];
$b2 = $chunk[3];
$b3 = $chunk[4];
$dest .=
static::$method( ($b0 >> 3) & 31) .
static::$method((($b0 << 2) | ($b1 >> 6)) & 31) .
static::$method((($b1 >> 1) ) & 31) .
static::$method((($b1 << 4) | ($b2 >> 4)) & 31) .
static::$method((($b2 << 1) | ($b3 >> 7)) & 31) .
static::$method((($b3 >> 2) ) & 31) .
static::$method((($b3 << 3) ) & 31);
if ($pad) {
$dest .= '=';
}
} elseif ($i + 2 < $srcLen) {
$b1 = $chunk[2];
$b2 = $chunk[3];
$dest .=
static::$method( ($b0 >> 3) & 31) .
static::$method((($b0 << 2) | ($b1 >> 6)) & 31) .
static::$method((($b1 >> 1) ) & 31) .
static::$method((($b1 << 4) | ($b2 >> 4)) & 31) .
static::$method((($b2 << 1) ) & 31);
if ($pad) {
$dest .= '===';
}
} elseif ($i + 1 < $srcLen) {
$b1 = $chunk[2];
$dest .=
static::$method( ($b0 >> 3) & 31) .
static::$method((($b0 << 2) | ($b1 >> 6)) & 31) .
static::$method((($b1 >> 1) ) & 31) .
static::$method((($b1 << 4) ) & 31);
if ($pad) {
$dest .= '====';
}
} else {
$dest .=
static::$method( ($b0 >> 3) & 31) .
static::$method( ($b0 << 2) & 31);
if ($pad) {
$dest .= '======';
}
}
}
return $dest;
}
}
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