Philippe Ranger wrote:

> 
> <<Bob:
> Besides, it would seem that wrapping around the best of the
> "bitsInByte" solutions would be both faster and less cumbersome.
> >>
> 
> Perhaps, but that involves one call per byte. 

By wrap I meant put the code inside a loop.  This is between 1.7 and 3x
faster depending on the size of the set on a PII, and it uses your
BitsInByte Nibble algorithm crushed into one pascal expression.


function card1(var tar; size: integer): integer;
const
  nibbleTable:array[0..15] of integer=( 0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2,
3, 2, 3, 3, 4);
var
  Data:PByteArray;
  i,b:integer;
begin
  result:=0;
  Data:=@TByteArray(tar)[size];
  i:=-size;
  while i<0 do
  begin
    b:=Data[i];
    inc(result,NibbleTable[b and $F]+NibbleTable[(b shr 4) and $F]);
    inc(i);
  end;
end;




-- 
Bob Lee
High Performance Delphi - http://www.econos.com/optimize/
Updated August 2