<?php
/**
* Class ParagonIE_Sodium_Core_Base64UrlSafe
*
* Copyright (c) 2016 - 2018 Paragon Initiative Enterprises.
* Copyright (c) 2014 Steve "Sc00bz" Thomas (steve at tobtu dot com)
*/
class ParagonIE_Sodium_Core_Base64_UrlSafe
{
// COPY ParagonIE_Sodium_Core_Base64_Common STARTING HERE
/**
* 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;
}
// COPY ParagonIE_Sodium_Core_Base64_Common ENDING HERE
/**
* 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 $src
* @return int
*/
protected static function decode6Bits($src)
{
$ret = -1;
// if ($src > 0x40 && $src < 0x5b) $ret += $src - 0x41 + 1; // -64
$ret += (((0x40 - $src) & ($src - 0x5b)) >> 8) & ($src - 64);
// if ($src > 0x60 && $src < 0x7b) $ret += $src - 0x61 + 26 + 1; // -70
$ret += (((0x60 - $src) & ($src - 0x7b)) >> 8) & ($src - 70);
// if ($src > 0x2f && $src < 0x3a) $ret += $src - 0x30 + 52 + 1; // 5
$ret += (((0x2f - $src) & ($src - 0x3a)) >> 8) & ($src + 5);
// if ($src == 0x2c) $ret += 62 + 1;
$ret += (((0x2c - $src) & ($src - 0x2e)) >> 8) & 63;
// if ($src == 0x5f) ret += 63 + 1;
$ret += (((0x5e - $src) & ($src - 0x60)) >> 8) & 64;
return $ret;
}
/**
* Uses bitwise operators instead of table-lookups to turn 8-bit integers
* into 6-bit integers.
*
* @param int $src
* @return string
*/
protected static function encode6Bits($src)
{
$diff = 0x41;
// if ($src > 25) $diff += 0x61 - 0x41 - 26; // 6
$diff += ((25 - $src) >> 8) & 6;
// if ($src > 51) $diff += 0x30 - 0x61 - 26; // -75
$diff -= ((51 - $src) >> 8) & 75;
// if ($src > 61) $diff += 0x2d - 0x30 - 10; // -13
$diff -= ((61 - $src) >> 8) & 13;
// if ($src > 62) $diff += 0x5f - 0x2b - 1; // 3
$diff += ((62 - $src) >> 8) & 49;
return pack('C', $src + $diff);
}
}
في جولة حصرية داخل “الغرفة الزرقاء” بقناة BBC العربية، نكشف كواليس واحدة من أكثر غرف الأخبار تطورًا في العالم.
كيف الذكاء اصطناعي يتحكم بالبث دون تدخل بشري، لتقدم تجربة بصرية مذهلة.
الفيديو يستعرض كيف تمزج BBC بين التقنية والاحتراف لتصنع نشرات إخبارية من قلب المستقبل.