File ICal/Serializer.php | PHP iCal Parser API

1:	<?php
2:	declare(strict_types=1);
3:
4:	namespace om\ICal;
5:
6:	/**
7:	* Writes components as iCalendar data (RFC 5545, section 3.1): CRLF line breaks and
8:	* lines folded at 75 octets without splitting UTF-8 characters. Properties are written
9:	* with their raw values, so unknown and X- properties are kept unchanged.
10:	*/
11:	final class Serializer {
12:	public static function serialize(Component $component): string {
13:	$result = 'BEGIN:' . $component->name . "\r\n";
14:	foreach ($component->properties as $property) {
15:	$result .= self::fold((string) $property);
16:	}
17:	foreach ($component->components as $child) {
18:	$result .= self::serialize($child);
19:	}
20:	return $result . 'END:' . $component->name . "\r\n";
21:	}
22:
23:	/**
24:	* Fold a content line into chunks of at most 75 octets.
25:	*/
26:	public static function fold(string $line): string {
27:	$result = '';
28:	$limit = 75;
29:	while (strlen($line) > $limit) {
30:	$cut = $limit;
31:	while ($cut > 1 && (ord($line[$cut]) & 0xC0) === 0x80) {
32:	$cut--; // do not split a multibyte character
33:	}
34:	$result .= substr($line, 0, $cut) . "\r\n ";
35:	$line = substr($line, $cut);
36:	$limit = 74; // the leading space counts
37:	}
38:	return $result . $line . "\r\n";
39:	}
40:	}
41: