// Copyright 2017 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.

// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris

package unix

import "time"

// TimespecToNsec converts a Timespec value into a number of

// nanoseconds since the Unix epoch.

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

// NsecToTimespec takes a number of nanoseconds since the Unix epoch

// and returns the corresponding Timespec value.

func NsecToTimespec(nsec int64) Timespec {

	sec := nsec / 1e9

	nsec = nsec % 1e9

	if nsec < 0 {

		nsec += 1e9

		sec--

	}

	return setTimespec(sec, nsec)

}

// TimeToTimespec converts t into a Timespec.

// On some 32-bit systems the range of valid Timespec values are smaller

// than that of time.Time values.  So if t is out of the valid range of

// Timespec, it returns a zero Timespec and ERANGE.

func TimeToTimespec(t time.Time) (Timespec, error) {

	sec := t.Unix()

	nsec := int64(t.Nanosecond())

	ts := setTimespec(sec, nsec)

	// Currently all targets have either int32 or int64 for Timespec.Sec.

	// If there were a new target with floating point type for it, we have

	// to consider the rounding error.

	if int64(ts.Sec) != sec {

		return Timespec{}, ERANGE

	}

	return ts, nil

}

// TimevalToNsec converts a Timeval value into a number of nanoseconds

// since the Unix epoch.

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

// NsecToTimeval takes a number of nanoseconds since the Unix epoch

// and returns the corresponding Timeval value.

func NsecToTimeval(nsec int64) Timeval {

	nsec += 999 // round up to microsecond

	usec := nsec % 1e9 / 1e3

	sec := nsec / 1e9

	if usec < 0 {

		usec += 1e6

		sec--

	}

	return setTimeval(sec, usec)

}

// Unix returns ts as the number of seconds and nanoseconds elapsed since the

// Unix epoch.

func (ts *Timespec) Unix() (sec int64, nsec int64) {

	return int64(ts.Sec), int64(ts.Nsec)

}

// Unix returns tv as the number of seconds and nanoseconds elapsed since the

// Unix epoch.

func (tv *Timeval) Unix() (sec int64, nsec int64) {

	return int64(tv.Sec), int64(tv.Usec) * 1000

}

// Nano returns ts as the number of nanoseconds elapsed since the Unix epoch.

func (ts *Timespec) Nano() int64 {

	return int64(ts.Sec)*1e9 + int64(ts.Nsec)

}

// Nano returns tv as the number of nanoseconds elapsed since the Unix epoch.

func (tv *Timeval) Nano() int64 {

	return int64(tv.Sec)*1e9 + int64(tv.Usec)*1000

}