// Copyright 2009 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 syscall

import "unsafe"

func Getpagesize() int { return 4096 }

func TimespecToNsec(ts Timespec) int64 { return int64(ts.Sec)*1e9 + int64(ts.Nsec) }

func NsecToTimespec(nsec int64) (ts Timespec) {
	ts.Sec = int32(nsec / 1e9)
	ts.Nsec = int32(nsec % 1e9)
	return
}

func TimevalToNsec(tv Timeval) int64 { return int64(tv.Sec)*1e9 + int64(tv.Usec)*1e3 }

func NsecToTimeval(nsec int64) (tv Timeval) {
	nsec += 999 // round up to microsecond
	tv.Usec = int32(nsec % 1e9 / 1e3)
	tv.Sec = int32(nsec / 1e9)
	return
}

//sysnb	gettimeofday(tp *Timeval) (sec int32, usec int32, err error)
func Gettimeofday(tv *Timeval) error {
	// The tv passed to gettimeofday must be non-nil.
	// Before macOS Sierra (10.12), tv was otherwise unused and
	// the answers came back in the two registers.
	// As of Sierra, gettimeofday return zeros and populates
	// tv itself.
	sec, usec, err := gettimeofday(tv)
	if err != nil {
		return err
	}
	if sec != 0 || usec != 0 {
		tv.Sec = int32(sec)
		tv.Usec = int32(usec)
	}
	return nil
}

func SetKevent(k *Kevent_t, fd, mode, flags int) {
	k.Ident = uint32(fd)
	k.Filter = int16(mode)
	k.Flags = uint16(flags)
}

func (iov *Iovec) SetLen(length int) {
	iov.Len = uint32(length)
}

func (msghdr *Msghdr) SetControllen(length int) {
	msghdr.Controllen = uint32(length)
}

func (cmsg *Cmsghdr) SetLen(length int) {
	cmsg.Len = uint32(length)
}

func sendfile(outfd int, infd int, offset *int64, count int) (written int, err error) {
	var length = uint64(count)

	_, _, e1 := Syscall9(SYS_SENDFILE, uintptr(infd), uintptr(outfd), uintptr(*offset), uintptr(*offset>>32), uintptr(unsafe.Pointer(&length)), 0, 0, 0, 0)

	written = int(length)

	if e1 != 0 {
		err = e1
	}
	return
}

func Syscall9(num, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r1, r2 uintptr, err Errno) // sic
