C++程序  |  81行  |  2.1 KB

/*
 * Copyright (C) 2017 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#ifndef __CMD_H__
#define __CMD_H__

#define _IOC_NRBITS     8
#define _IOC_TYPEBITS   8

/*
 * Let any architecture override either of the following before
 * including this file.
 */

#ifndef _IOC_SIZEBITS
# define _IOC_SIZEBITS  14
#endif

#ifndef _IOC_DIRBITS
# define _IOC_DIRBITS   2
#endif

#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, which any architecture can choose to override
 * before including this file.
 */

#ifndef _IOC_NONE
# define _IOC_NONE      0U
#endif

#ifndef _IOC_WRITE
# define _IOC_WRITE     1U
#endif

#ifndef _IOC_READ
# define _IOC_READ      2U
#endif



#define _IOC_TYPECHECK(t) (sizeof(t))
#define _IOC(dir,type,nr,size) \
        (((dir)  << _IOC_DIRSHIFT) | \
         ((type) << _IOC_TYPESHIFT) | \
         ((nr)   << _IOC_NRSHIFT) | \
         ((size) << _IOC_SIZESHIFT))



/* 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)))

#endif