my $Set = qr/[^$CharSet]/;
length join "", split $Set, $SearchStr;

##</code><code>##

sub CountSetChars
  {
  my $Count;
  my $CharSet = shift;
  my $Set = qr/[^$CharSet]/;
  my $Param;

  while ($Param = shift)
    {
    if (defined @$Param)
      {map {$Count += CountSetChars ($CharSet, $_)} @$Param;}
    elsif (ref $Param)
      {$Count += length join "", split $Set, @$Param;}
    else
      {$Count += length join "", split $Set, $Param;}
    }
  return $Count;
  }