Truncates a UTF-8-encoded string safely to a number of bytes.
If the end position is in the middle of a UTF-8 sequence, it scans backwards until the beginning of the byte sequence.
Use this function whenever you want to chop off a string at an unsure location. On the other hand, if you're sure that you're splitting on a character boundary (e.g. after using strpos() or similar), you can safely use substr() instead.
string $string: The string to truncate.
int $len: An upper limit on the returned string length.
string The truncated string.
public static function truncateBytes($string, $len) {
if (strlen($string) <= $len) {
return $string;
}
if (ord($string[$len]) < 0x80 || ord($string[$len]) >= 0xc0) {
return substr($string, 0, $len);
}
// Scan backwards to beginning of the byte sequence.
while (--$len >= 0 && ord($string[$len]) >= 0x80 && ord($string[$len]) < 0xc0) {
}
return substr($string, 0, $len);
}