github.com/Andyfoo/golang/x/sys@v0.0.0-20190901054642-57c1bf301704/unix/dev_openbsd.go (about)

     1  // Copyright 2017 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // Functions to access/create device major and minor numbers matching the
     6  // encoding used in OpenBSD's sys/types.h header.
     7  
     8  package unix
     9  
    10  // Major returns the major component of an OpenBSD device number.
    11  func Major(dev uint64) uint32 {
    12  	return uint32((dev & 0x0000ff00) >> 8)
    13  }
    14  
    15  // Minor returns the minor component of an OpenBSD device number.
    16  func Minor(dev uint64) uint32 {
    17  	minor := uint32((dev & 0x000000ff) >> 0)
    18  	minor |= uint32((dev & 0xffff0000) >> 8)
    19  	return minor
    20  }
    21  
    22  // Mkdev returns an OpenBSD device number generated from the given major and minor
    23  // components.
    24  func Mkdev(major, minor uint32) uint64 {
    25  	dev := (uint64(major) << 8) & 0x0000ff00
    26  	dev |= (uint64(minor) << 8) & 0xffff0000
    27  	dev |= (uint64(minor) << 0) & 0x000000ff
    28  	return dev
    29  }