$string ='    aaaa    bbbbccccccccbbbb   aaaabbbbbcdddddddddddddddddddd';

$l = length($string);
$pp = 0;
while ($pp < $l) {
  $c = substr $string, $pp, 1;
	if ($string =~ /\G\Q$c\E+/gc) {
		print "('$c',", $pp, ",",pos($string) - $pp,")\n";
		$pp = pos($string);
	}
}