<?php
/**
* Class ParagonIE_Sodium_Core_Base64
*
* Copyright (c) 2016 - 2018 Paragon Initiative Enterprises.
* Copyright (c) 2014 Steve "Sc00bz" Thomas (steve at tobtu dot com)
*
* We have to copy/paste the contents into the variant files because PHP 5.2
* doesn't support late static binding, and we have no better workaround
* available that won't break PHP 7+. Therefore, we're forced to duplicate code.
*/
abstract class ParagonIE_Sodium_Core_Base64_Common
{
/**
* Encode into Base64
*
* Base64 character set "[A-Z][a-z][0-9]+/"
*
* @param string $src
* @return string
* @throws TypeError
*/
public static function encode($src)
{
return self::doEncode($src, true);
}
/**
* Encode into Base64, no = padding
*
* Base64 character set "[A-Z][a-z][0-9]+/"
*
* @param string $src
* @return string
* @throws TypeError
*/
public static function encodeUnpadded($src)
{
return self::doEncode($src, false);
}
/**
* @param string $src
* @param bool $pad Include = padding?
* @return string
* @throws TypeError
*/
protected static function doEncode($src, $pad = true)
{
$dest = '';
$srcLen = ParagonIE_Sodium_Core_Util::strlen($src);
// Main loop (no padding):
for ($i = 0; $i + 3 <= $srcLen; $i += 3) {
/** @var array<int, int> $chunk */
$chunk = unpack('C*', ParagonIE_Sodium_Core_Util::substr($src, $i, 3));
$b0 = $chunk[1];
$b1 = $chunk[2];
$b2 = $chunk[3];
$dest .=
self::encode6Bits( $b0 >> 2 ) .
self::encode6Bits((($b0 << 4) | ($b1 >> 4)) & 63) .
self::encode6Bits((($b1 << 2) | ($b2 >> 6)) & 63) .
self::encode6Bits( $b2 & 63);
}
// The last chunk, which may have padding:
if ($i < $srcLen) {
/** @var array<int, int> $chunk */
$chunk = unpack('C*', ParagonIE_Sodium_Core_Util::substr($src, $i, $srcLen - $i));
$b0 = $chunk[1];
if ($i + 1 < $srcLen) {
$b1 = $chunk[2];
$dest .=
self::encode6Bits($b0 >> 2) .
self::encode6Bits((($b0 << 4) | ($b1 >> 4)) & 63) .
self::encode6Bits(($b1 << 2) & 63);
if ($pad) {
$dest .= '=';
}
} else {
$dest .=
self::encode6Bits( $b0 >> 2) .
self::encode6Bits(($b0 << 4) & 63);
if ($pad) {
$dest .= '==';
}
}
}
return $dest;
}
/**
* decode from base64 into binary
*
* Base64 character set "./[A-Z][a-z][0-9]"
*
* @param string $src
* @param bool $strictPadding
* @return string
* @throws RangeException
* @throws TypeError
* @psalm-suppress RedundantCondition
*/
public static function decode($src, $strictPadding = false)
{
// Remove padding
$srcLen = ParagonIE_Sodium_Core_Util::strlen($src);
if ($srcLen === 0) {
return '';
}
if ($strictPadding) {
if (($srcLen & 3) === 0) {
if ($src[$srcLen - 1] === '=') {
$srcLen--;
if ($src[$srcLen - 1] === '=') {
$srcLen--;
}
}
}
if (($srcLen & 3) === 1) {
throw new RangeException(
'Incorrect padding'
);
}
if ($src[$srcLen - 1] === '=') {
throw new RangeException(
'Incorrect padding'
);
}
} else {
$src = rtrim($src, '=');
$srcLen = ParagonIE_Sodium_Core_Util::strlen($src);
}
$err = 0;
$dest = '';
// Main loop (no padding):
for ($i = 0; $i + 4 <= $srcLen; $i += 4) {
/** @var array<int, int> $chunk */
$chunk = unpack('C*', ParagonIE_Sodium_Core_Util::substr($src, $i, 4));
$c0 = self::decode6Bits($chunk[1]);
$c1 = self::decode6Bits($chunk[2]);
$c2 = self::decode6Bits($chunk[3]);
$c3 = self::decode6Bits($chunk[4]);
$dest .= pack(
'CCC',
((($c0 << 2) | ($c1 >> 4)) & 0xff),
((($c1 << 4) | ($c2 >> 2)) & 0xff),
((($c2 << 6) | $c3 ) & 0xff)
);
$err |= ($c0 | $c1 | $c2 | $c3) >> 8;
}
// The last chunk, which may have padding:
if ($i < $srcLen) {
/** @var array<int, int> $chunk */
$chunk = unpack('C*', ParagonIE_Sodium_Core_Util::substr($src, $i, $srcLen - $i));
$c0 = self::decode6Bits($chunk[1]);
if ($i + 2 < $srcLen) {
$c1 = self::decode6Bits($chunk[2]);
$c2 = self::decode6Bits($chunk[3]);
$dest .= pack(
'CC',
((($c0 << 2) | ($c1 >> 4)) & 0xff),
((($c1 << 4) | ($c2 >> 2)) & 0xff)
);
$err |= ($c0 | $c1 | $c2) >> 8;
} elseif ($i + 1 < $srcLen) {
$c1 = self::decode6Bits($chunk[2]);
$dest .= pack(
'C',
((($c0 << 2) | ($c1 >> 4)) & 0xff)
);
$err |= ($c0 | $c1) >> 8;
} elseif ($i < $srcLen && $strictPadding) {
$err |= 1;
}
}
/** @var bool $check */
$check = ($err === 0);
if (!$check) {
throw new RangeException(
'Base64::decode() only expects characters in the correct base64 alphabet'
);
}
return $dest;
}
/**
* Uses bitwise operators instead of table-lookups to turn 6-bit integers
* into 8-bit integers.
*
* Base64 character set:
* [A-Z] [a-z] [0-9] + /
* 0x41-0x5a, 0x61-0x7a, 0x30-0x39, 0x2b, 0x2f
*
* @param int $src
* @return int
*/
abstract protected static function decode6Bits($src);
/**
* Uses bitwise operators instead of table-lookups to turn 8-bit integers
* into 6-bit integers.
*
* @param int $src
* @return string
*/
abstract protected static function encode6Bits($src);
}