btrfs-disk 0.13.0

Platform-independent parsing and writing of btrfs on-disk structures
Documentation 
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/* Portable shim for <linux/ioctl.h>.
 *
 * On Linux this header is provided by the kernel; on other platforms we
 * supply the _IO/_IOR/_IOW/_IOWR macros so btrfs.h can be parsed.  The
 * encoding matches the Linux generic-asm ioctl.h so any BTRFS_IOC_*
 * constant computed here has the same value as on Linux — the disk
 * crate doesn't actually issue ioctls, but downstream consumers may.
 */
#ifndef _LINUX_IOCTL_H
#define _LINUX_IOCTL_H

#define _IOC_NRBITS    8
#define _IOC_TYPEBITS  8
#define _IOC_SIZEBITS 14
#define _IOC_DIRBITS   2

#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)

#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 _IOC_TYPECHECK(t) (sizeof(t))

#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))

#endif /* _LINUX_IOCTL_H */