// 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 unix

import (
	"syscall"
	"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
}

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 writtenOut uint64 = 0
	_, _, e1 := Syscall9(SYS_SENDFILE, uintptr(infd), uintptr(outfd), uintptr(*offset), uintptr((*offset)>>32), uintptr(count), 0, uintptr(unsafe.Pointer(&writtenOut)), 0, 0)

	written = int(writtenOut)

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

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