/* 
   ------------------------------------------------------
   Methode KeyboardLED zur Steuerung der Keyboard-LEDs
   (NumLock/CapsLock/ScrollLock-Lichter)
   
   Benutzungshinweise: Man benutze
   KeyboardLED(LEDvalue,"Cmd"), wobei
   Cmd = on/off/switch,
   LEDvalue: ScrollLock=1, NumLock=2, CapsLock=4
   bzw. eine beliebige Summe dieser Werte:
   AlleAus=0, CapsLock+NumLock=6, etc.
   
   Der folgende Code wurde übernommen von:
   http://www.autohotkey.com/forum/viewtopic.php?t=10532
   
   Um eventuelle Wechselwirkungen mit dem bestehenden
   Code (insb. der Unicode-Konvertierung) auszuschießen,
   sind auch alle (Hilfsmethoden) mit dem Postfix LED
   versehen worden.
   ------------------------------------------------------
*/

KeyboardLED(LEDvalue, Cmd)  ; LEDvalue: ScrollLock=1, NumLock=2, CapsLock=4 ; Cmd = on/off/switch
{
  Static h_device
  If ! h_device ; initialise
    {
    device =\Device\KeyBoardClass0
    SetUnicodeStrLED(fn,device) 
    h_device:=NtCreateFileLED(fn,0+0x00000100+0x00000080+0x00100000,1,1,0x00000040+0x00000020,0)
    }

  VarSetCapacity( output_actual, 4, 0 )
  input_size = 4
  VarSetCapacity( input, input_size, 0 )

  If Cmd= switch  ;switches every LED according to LEDvalue
   KeyLED:= LEDvalue
  If Cmd= on  ;forces all choosen LED's to ON (LEDvalue= 0 ->LED's according to keystate)
   KeyLED:= LEDvalue | (GetKeyState("ScrollLock", "T") + 2*GetKeyState("NumLock", "T") + 4*GetKeyState("CapsLock", "T"))
  If Cmd= off  ;forces all choosen LED's to OFF (LEDvalue= 0 ->LED's according to keystate)
    {
    LEDvalue:= LEDvalue ^ 7
    KeyLED:= LEDvalue & (GetKeyState("ScrollLock", "T") + 2*GetKeyState("NumLock", "T") + 4*GetKeyState("CapsLock", "T"))
    }
  ; EncodeIntegerLED( KeyLED, 1, &input, 2 ) ;input bit pattern (KeyLED): bit 0 = scrolllock ;bit 1 = numlock ;bit 2 = capslock
  input := Chr(1) Chr(1) Chr(KeyLED)
  input := Chr(1)
  input=
  success := DllCall( "DeviceIoControl"
              , "uint", h_device
              , "uint", CTL_CODE_LED( 0x0000000b     ; FILE_DEVICE_KEYBOARD
                        , 2
                        , 0             ; METHOD_BUFFERED
                        , 0  )          ; FILE_ANY_ACCESS
              , "uint", &input
              , "uint", input_size
              , "uint", 0
              , "uint", 0
              , "uint", &output_actual
              , "uint", 0 )
}

CTL_CODE_LED( p_device_type, p_function, p_method, p_access )
{
  Return, ( p_device_type << 16 ) | ( p_access << 14 ) | ( p_function << 2 ) | p_method
}


NtCreateFileLED(ByRef wfilename,desiredaccess,sharemode,createdist,flags,fattribs)
{ 
  VarSetCapacity(fh,4,0) 
  VarSetCapacity(objattrib,24,0) 
  VarSetCapacity(io,8,0) 
  VarSetCapacity(pus,8) 
  uslen:=DllCall("lstrlenW","str",wfilename)*2 
  InsertIntegerLED(uslen,pus,0,2) 
  InsertIntegerLED(uslen,pus,2,2) 
  InsertIntegerLED(&wfilename,pus,4) 
  InsertIntegerLED(24,objattrib,0) 
  InsertIntegerLED(&pus,objattrib,8) 
  status:=DllCall("ntdll\ZwCreateFile","str",fh,"UInt",desiredaccess,"str",objattrib,"str",io,"UInt",0,"UInt",fattribs
                  ,"UInt",sharemode,"UInt",createdist,"UInt",flags,"UInt",0,"UInt",0, "UInt") 
  return ExtractIntegerLED(fh) 
} 


SetUnicodeStrLED(ByRef out, str_)
{ 
  VarSetCapacity(st1, 8, 0) 
  InsertIntegerLED(0x530025, st1) 
  VarSetCapacity(out, (StrLen(str_)+1)*2, 0) 
  DllCall("wsprintfW", "str", out, "str", st1, "str", str_, "Cdecl UInt") 
} 


ExtractIntegerLED(ByRef pSource, pOffset = 0, pIsSigned = false, pSize = 4) 
; pSource is a string (buffer) whose memory area contains a raw/binary integer at pOffset. 
; The caller should pass true for pSigned to interpret the result as signed vs. unsigned. 
; pSize is the size of PSource's integer in bytes (e.g. 4 bytes for a DWORD or Int). 
; pSource must be ByRef to avoid corruption during the formal-to-actual copying process 
; (since pSource might contain valid data beyond its first binary zero). 
{ 
  Loop %pSize%  ; Build the integer by adding up its bytes. 
    result += *(&pSource + pOffset + A_Index-1) << 8*(A_Index-1) 
  if (!pIsSigned OR pSize > 4 OR result < 0x80000000) 
    return result  ; Signed vs. unsigned doesn't matter in these cases. 
  ; Otherwise, convert the value (now known to be 32-bit) to its signed counterpart: 
  return -(0xFFFFFFFF - result + 1) 
} 


InsertIntegerLED(pInteger, ByRef pDest, pOffset = 0, pSize = 4) 
; The caller must ensure that pDest has sufficient capacity.  To preserve any existing contents in pDest, 
; only pSize number of bytes starting at pOffset are altered in it. 
{ 
  Loop %pSize%  ; Copy each byte in the integer into the structure as raw binary data. 
    DllCall("RtlFillMemory", "UInt", &pDest + pOffset + A_Index-1, "UInt", 1, "UChar", pInteger >> 8*(A_Index-1) & 0xFF) 
}