Not enought laconically, although fast enought:

$string ='    aaaa    bbbbccccccccbbbb   aaaabbbbbcddddddddddddddddddd
+d';

$l = length($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);
    }
}
[download]