name : Base64Encoder.php <?php /* * This file is part of the Symfony package. * * (c) Fabien Potencier <fabien@symfony.com> * * For the full copyright and license information, please view the LICENSE * file that was distributed with this source code. */ namespace Symfony\Component\Mime\Encoder; /** * @author Chris Corbyn */ class Base64Encoder implements EncoderInterface { /** * Takes an unencoded string and produces a Base64 encoded string from it. * * Base64 encoded strings have a maximum line length of 76 characters. * If the first line needs to be shorter, indicate the difference with * $firstLineOffset. */ public function encodeString(string $string, ?string $charset = 'utf-8', int $firstLineOffset = 0, int $maxLineLength = 0): string { if (0 >= $maxLineLength || 76 < $maxLineLength) { $maxLineLength = 76; } $encodedString = base64_encode($string); $firstLine = ''; if (0 !== $firstLineOffset) { $firstLine = substr($encodedString, 0, $maxLineLength - $firstLineOffset)."\r\n"; $encodedString = substr($encodedString, $maxLineLength - $firstLineOffset); } return $firstLine.trim(chunk_split($encodedString, $maxLineLength, "\r\n")); } }