Current File : /var/www/tif-dev/wp-content/plugins/worker/src/MWP/Stream/Base64EncodedStream.php
<?php
/*
* This file is part of the ManageWP Worker plugin.
*
* (c) ManageWP LLC <contact@managewp.com>
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
class MWP_Stream_Base64EncodedStream extends MWP_Stream_Decorator
{
/** @var MWP_Stream_Interface */
private $buffer;
const BASE64_BLOCK_SIZE = 4;
const ORIGIN_BLOCK_SIZE = 3;
public function __construct(MWP_Stream_Interface $stream)
{
parent::__construct($stream);
$this->buffer = new MWP_Stream_Buffer();
}
public function eof()
{
return $this->buffer->eof() && $this->getStream()->eof();
}
public function read($length)
{
$readFromBuffer = $this->buffer->read($length);
if (strlen($readFromBuffer) === $length) {
return $readFromBuffer;
}
$remaining = $length - strlen($readFromBuffer);
// Calculate the approximate length required to read so that the base64 encoded stream does not have padding.
// base64 is calculated for blocks of 3 input characters resulting in 4 output characters.
// strlen(base64_encode($str)) ==> strlen($str) * 4 / 3
//
// This leads to:
//
// strlen($str) ==> strlen(base64_encode($str)) * 3 / 4
//
// Meaning, to read $length characters from the base64 encoded string, read 3/4 of $length from the original stream.
// $length is first rounded to the first larger number divisible by 4 since base64 encoded strings come in blocks of 4 characters.
$closestGroupLength = $remaining + (self::BASE64_BLOCK_SIZE - $remaining % self::BASE64_BLOCK_SIZE);
$read = $closestGroupLength * self::ORIGIN_BLOCK_SIZE / self::BASE64_BLOCK_SIZE;
$this->buffer->write(base64_encode($this->getStream()->read($read)));
return $readFromBuffer.$this->buffer->read($remaining);
}
}
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