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<?php
/*
* This file is part of SwiftMailer.
* (c) 2004-2009 Chris Corbyn
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
/**
* Handles Base 64 Transfer Encoding in Swift Mailer.
*
* @author Chris Corbyn
*/
class Swift_Mime_ContentEncoder_Base64ContentEncoder extends Swift_Encoder_Base64Encoder implements Swift_Mime_ContentEncoder
{
/**
* Encode stream $in to stream $out.
*
* @param Swift_OutputByteStream $os
* @param Swift_InputByteStream $is
* @param int $firstLineOffset
* @param int $maxLineLength, optional, 0 indicates the default of 76 bytes
*/
public function encodeByteStream(Swift_OutputByteStream $os, Swift_InputByteStream $is, $firstLineOffset = 0, $maxLineLength = 0)
{
if (0 >= $maxLineLength || 76 < $maxLineLength) {
$maxLineLength = 76;
}
$remainder = 0;
$base64ReadBufferRemainderBytes = null;
// To reduce memory usage, the output buffer is streamed to the input buffer like so:
// Output Stream => base64encode => wrap line length => Input Stream
// HOWEVER it's important to note that base64_encode() should only be passed whole triplets of data (except for the final chunk of data)
// otherwise it will assume the input data has *ended* and it will incorrectly pad/terminate the base64 data mid-stream.
// We use $base64ReadBufferRemainderBytes to carry over 1-2 "remainder" bytes from the each chunk from OutputStream and pre-pend those onto the
// chunk of bytes read in the next iteration.
// When the OutputStream is empty, we must flush any remainder bytes.
while (true) {
$readBytes = $os->read(8192);
$atEOF = ($readBytes === false);
if ($atEOF) {
$streamTheseBytes = $base64ReadBufferRemainderBytes;
} else {
$streamTheseBytes = $base64ReadBufferRemainderBytes.$readBytes;
}
$base64ReadBufferRemainderBytes = null;
$bytesLength = strlen($streamTheseBytes);
if ($bytesLength === 0) { // no data left to encode
break;
}
// if we're not on the last block of the ouput stream, make sure $streamTheseBytes ends with a complete triplet of data
// and carry over remainder 1-2 bytes to the next loop iteration
if (!$atEOF) {
$excessBytes = $bytesLength % 3;
if ($excessBytes !== 0) {
$base64ReadBufferRemainderBytes = substr($streamTheseBytes, -$excessBytes);
$streamTheseBytes = substr($streamTheseBytes, 0, $bytesLength - $excessBytes);
}
}
$encoded = base64_encode($streamTheseBytes);
$encodedTransformed = '';
$thisMaxLineLength = $maxLineLength - $remainder - $firstLineOffset;
while ($thisMaxLineLength < strlen($encoded)) {
$encodedTransformed .= substr($encoded, 0, $thisMaxLineLength)."\r\n";
$firstLineOffset = 0;
$encoded = substr($encoded, $thisMaxLineLength);
$thisMaxLineLength = $maxLineLength;
$remainder = 0;
}
if (0 < $remainingLength = strlen($encoded)) {
$remainder += $remainingLength;
$encodedTransformed .= $encoded;
$encoded = null;
}
$is->write($encodedTransformed);
if ($atEOF) {
break;
}
}
}
/**
* Get the name of this encoding scheme.
* Returns the string 'base64'.
*
* @return string
*/
public function getName()
{
return 'base64';
}
}
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