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    <h3>Editing: Base64ContentEncoder.php</h3>
    <textarea name="content" rows="20" cols="80">&lt;?php

/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier &lt;fabien@symfony.com&gt;
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Symfony\Component\Mime\Encoder;

use Symfony\Component\Mime\Exception\RuntimeException;

/**
 * @author Fabien Potencier &lt;fabien@symfony.com&gt;
 */
final class Base64ContentEncoder extends Base64Encoder implements ContentEncoderInterface
{
    public function encodeByteStream($stream, int $maxLineLength = 0): iterable
    {
        if (!\is_resource($stream)) {
            throw new \TypeError(sprintf('Method &quot;%s&quot; takes a stream as a first argument.', __METHOD__));
        }

        $filter = stream_filter_append($stream, 'convert.base64-encode', \STREAM_FILTER_READ, [
            'line-length' =&gt; 0 &gt;= $maxLineLength || 76 &lt; $maxLineLength ? 76 : $maxLineLength,
            'line-break-chars' =&gt; &quot;\r\n&quot;,
        ]);
        if (!\is_resource($filter)) {
            throw new RuntimeException('Unable to set the base64 content encoder to the filter.');
        }

        while (!feof($stream)) {
            yield fread($stream, 16372);
        }
        stream_filter_remove($filter);
    }

    public function getName(): string
    {
        return 'base64';
    }
}
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