record an procedure übergeben

[shmia]

Ungetested (aber im Prinzip ok ):

Delphi-Quellcode:

function InternetChecksum(PData: PWord; Count: Integer):integer;
begin 
  result := 0; 
  while Count > 1 do
  begin 
    result := result + PData^; 
    Inc(PData);
    Dec(Count, 2); 
  end;
  
  // Add left-over byte, if any
  if Count > 0 then
     Result := Result + PByte(PData)^;

  // Fold 32-bit sum to 16 bits 
  while (Result and $FFFF000) <> 0 do
     Result := (Result and $FFFF) + (Result shr 16); 

  Result := not Result; 
end; 

procedure CheckSumIcmpHeader(var hdr:TIcmpHeader);
begin
   hdr.usCheckSum := 0;  // nicht wegoptimieren !!!
   hdr.usCheckSum := InternetCheckSum(PWord(@hdr), sizeof(TIcmpHeader));
end;