PHP获取远程文件大小函数

<?php
function GetFileSize($url) {
	$url = parse_url ( $url );
	if ($fp = @fsockopen ( $url ['host'], empty ( $url ['port'] ) ? 80 : $url ['port'], $error )) {
		fputs ( $fp, "GET " . (empty ( $url ['path'] ) ? '/' : $url ['path']) . " HTTP/1.1\r\n" );
		fputs ( $fp, "Host:$url[host]\r\n\r\n" );
		while ( ! feof ( $fp ) ) {
			$tmp = fgets ( $fp );
			if (trim ( $tmp ) == '') {
				break;
			} else if (preg_match ( '/Content-Length:(.*)/si', $tmp, $arr )) {
				return trim ( $arr [1] );
			}
		}
		return null;
	} else {
		return null;
	}
}
?>