// Copyright 2018 The Go Authors. All rights reserved.

// Use of this source code is governed by a BSD-style

// license that can be found in the LICENSE file.

package unix

import (

	"runtime"

	"unsafe"

)

// ioctl itself should not be exposed directly, but additional get/set

// functions for specific types are permissible.

// IoctlSetInt performs an ioctl operation which sets an integer value

// on fd, using the specified request number.

func IoctlSetInt(fd int, req uint, value int) error {

	return ioctl(fd, req, uintptr(value))

}

// IoctlSetPointerInt performs an ioctl operation which sets an

// integer value on fd, using the specified request number. The ioctl

// argument is called with a pointer to the integer value, rather than

// passing the integer value directly.

func IoctlSetPointerInt(fd int, req uint, value int) error {

	v := int32(value)

	return ioctl(fd, req, uintptr(unsafe.Pointer(&v)))

}

// IoctlSetWinsize performs an ioctl on fd with a *Winsize argument.

//

// To change fd's window size, the req argument should be TIOCSWINSZ.

func IoctlSetWinsize(fd int, req uint, value *Winsize) error {

	// TODO: if we get the chance, remove the req parameter and

	// hardcode TIOCSWINSZ.

	err := ioctl(fd, req, uintptr(unsafe.Pointer(value)))

	runtime.KeepAlive(value)

	return err

}

// IoctlSetTermios performs an ioctl on fd with a *Termios.

//

// The req value will usually be TCSETA or TIOCSETA.

func IoctlSetTermios(fd int, req uint, value *Termios) error {

	// TODO: if we get the chance, remove the req parameter.

	err := ioctl(fd, req, uintptr(unsafe.Pointer(value)))

	runtime.KeepAlive(value)

	return err

}

// IoctlGetInt performs an ioctl operation which gets an integer value

// from fd, using the specified request number.

//

// A few ioctl requests use the return value as an output parameter;

// for those, IoctlRetInt should be used instead of this function.

func IoctlGetInt(fd int, req uint) (int, error) {

	var value int

	err := ioctl(fd, req, uintptr(unsafe.Pointer(&value)))

	return value, err

}

func IoctlGetWinsize(fd int, req uint) (*Winsize, error) {

	var value Winsize

	err := ioctl(fd, req, uintptr(unsafe.Pointer(&value)))

	return &value, err

}

func IoctlGetTermios(fd int, req uint) (*Termios, error) {

	var value Termios

	err := ioctl(fd, req, uintptr(unsafe.Pointer(&value)))

	return &value, err

}