text: /* 
   * by WN @ Jul 01, 2009
   */
  
  #ifndef IOCTL_H
  #define IOCTL_H
  
  
  #define _IOC_NRBITS	8
  #define _IOC_TYPEBITS	8
  #define _IOC_SIZEBITS	14
  #define _IOC_DIRBITS	2
  
  #define _IOC_NRMASK	((1 << _IOC_NRBITS)-1)
  #define _IOC_TYPEMASK	((1 << _IOC_TYPEBITS)-1)
  #define _IOC_SIZEMASK	((1 << _IOC_SIZEBITS)-1)
  #define _IOC_DIRMASK	((1 << _IOC_DIRBITS)-1)
  
  #define _IOC_NRSHIFT	0
  #define _IOC_TYPESHIFT	(_IOC_NRSHIFT+_IOC_NRBITS)
  #define _IOC_SIZESHIFT	(_IOC_TYPESHIFT+_IOC_TYPEBITS)
  #define _IOC_DIRSHIFT	(_IOC_SIZESHIFT+_IOC_SIZEBITS)
  
  /*
   * Direction bits.
   */
  #define _IOC_NONE	0U
  #define _IOC_WRITE	1U
  #define _IOC_READ	2U
  
  #define _IOC(dir,type,nr,size) \
  	(((dir)  << _IOC_DIRSHIFT) | \
  	 ((type) << _IOC_TYPESHIFT) | \
  	 ((nr)   << _IOC_NRSHIFT) | \
  	 ((size) << _IOC_SIZESHIFT))
  
  #define __invalid_size_argument_for_IOC	((1 << _IOC_SIZEBITS) - 1)
  #define _IOC_TYPECHECK(t) \
  	((sizeof(t) == sizeof(t[1]) && \
  	  sizeof(t) < (1 << _IOC_SIZEBITS)) ? \
  	  sizeof(t) : __invalid_size_argument_for_IOC)
  
  /* used to create numbers */
  #define _IO(type,nr)		_IOC(_IOC_NONE,(type),(nr),0)
  #define _IOR(type,nr,size)	_IOC(_IOC_READ,(type),(nr),(_IOC_TYPECHECK(size)))
  #define _IOW(type,nr,size)	_IOC(_IOC_WRITE,(type),(nr),(_IOC_TYPECHECK(size)))
  #define _IOWR(type,nr,size)	_IOC(_IOC_READ|_IOC_WRITE,(type),(nr),(_IOC_TYPECHECK(size)))
  #define _IOR_BAD(type,nr,size)	_IOC(_IOC_READ,(type),(nr),sizeof(size))
  #define _IOW_BAD(type,nr,size)	_IOC(_IOC_WRITE,(type),(nr),sizeof(size))
  #define _IOWR_BAD(type,nr,size)	_IOC(_IOC_READ|_IOC_WRITE,(type),(nr),sizeof(size))
  
  /* used to decode ioctl numbers.. */
  #define _IOC_DIR(nr)		(((nr) >> _IOC_DIRSHIFT) & _IOC_DIRMASK)
  #define _IOC_TYPE(nr)		(((nr) >> _IOC_TYPESHIFT) & _IOC_TYPEMASK)
  #define _IOC_NR(nr)		(((nr) >> _IOC_NRSHIFT) & _IOC_NRMASK)
  #define _IOC_SIZE(nr)		(((nr) >> _IOC_SIZESHIFT) & _IOC_SIZEMASK)
  
  /* ...and for the drivers/sound files... */
  
  #define IOC_IN		(_IOC_WRITE << _IOC_DIRSHIFT)
  #define IOC_OUT		(_IOC_READ << _IOC_DIRSHIFT)
  #define IOC_INOUT	((_IOC_WRITE|_IOC_READ) << _IOC_DIRSHIFT)
  #define IOCSIZE_MASK	(_IOC_SIZEMASK << _IOC_SIZESHIFT)
  #define IOCSIZE_SHIFT	(_IOC_SIZESHIFT)
  
  #endif
  
  