libc/include/sys/sysmacros.h

/*
 * Copyright (C) 2008 The Android Open Source Project
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *  * Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *  * Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#pragma once

/**
 * @file sys/sysmacros.h
 * @brief Major/minor device number macros.
 */

#include <sys/cdefs.h>

/** Combines `major` and `minor` into a device number. */
#define makedev(__major, __minor) \
  ( \
    (((__major) & 0xfffff000ULL) << 32) | (((__major) & 0xfffULL) << 8) | \
    (((__minor) & 0xffffff00ULL) << 12) | (((__minor) & 0xffULL)) \
  )

/** Extracts the major part of a device number. */
#define major(__dev) \
  ((unsigned) ((((unsigned long long) (__dev) >> 32) & 0xfffff000) | (((__dev) >> 8) & 0xfff)))

/** Extracts the minor part of a device number. */
#define minor(__dev) \
  ((unsigned) ((((__dev) >> 12) & 0xffffff00) | ((__dev) & 0xff)))