$query = $ENV{QUERY_STRING};

if (defined($query) && $query ne '') {
  foreach (split (/&/, $query)) {  #change to /[&;]/, right?
    y/+/ /;
    s/%(..)/sprintf("%c", hex($1))/ge;    # unquote %-quoted
 #change above to chr hex $1?
    if (/(\S+)=(.*)/) { # change \S to [^=], I'd say
      $input{$1} = $2 if ($2 ne ""); #and what if it is?
    } else {
      $input{$_}++;
    }
  }
}