mORMot Open Source

function StrToIPv4( const AValue: AnsiString; var IPv4: UInt32 ): Boolean; inline;
var
  O, I, C, V: Byte;
  Data: array[0..3] of Byte absolute IPv4;
begin
  // * Inital result
  Result := False;

  // * Reset main iterator
  I := 0;
  // * Walk IPv4 octets
  for O := 3 downto 0 do
  begin
    // * Octet value
    V := 0;
    // * Octet loop
    while True do
    begin
      // * Increase character iterator
      Inc( I );
      // * Get character
      C := Byte( AValue[I] );

      // * If NULL or dot [.]
      if ( C = 0 ) or ( C = 46 ) then Break;
      // * If space [ ]
      if ( C = 32 ) then Continue;

      // * If digit
      if ( C >= 48 ) and ( C <= 57 ) then
        // * Calculate octet value
        V := V * 10 + ( C - 48 )
      else
        // * Exit function
        Exit;

    end;
    // * Write octet value
    Data[O] := V;
  end;

  // * Assign result
  Result := True;
end;