github.com/Andyfoo/golang/x/sys@v0.0.0-20190901054642-57c1bf301704/unix/timestruct.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  // +build aix darwin dragonfly freebsd linux netbsd openbsd solaris
     6  
     7  package unix
     8  
     9  import "time"
    10  
    11  // TimespecToNsec converts a Timespec value into a number of
    12  // nanoseconds since the Unix epoch.
    13  func TimespecToNsec(ts Timespec) int64 { return int64(ts.Sec)*1e9 + int64(ts.Nsec) }
    14  
    15  // NsecToTimespec takes a number of nanoseconds since the Unix epoch
    16  // and returns the corresponding Timespec value.
    17  func NsecToTimespec(nsec int64) Timespec {
    18  	sec := nsec / 1e9
    19  	nsec = nsec % 1e9
    20  	if nsec < 0 {
    21  		nsec += 1e9
    22  		sec--
    23  	}
    24  	return setTimespec(sec, nsec)
    25  }
    26  
    27  // TimeToTimespec converts t into a Timespec.
    28  // On some 32-bit systems the range of valid Timespec values are smaller
    29  // than that of time.Time values.  So if t is out of the valid range of
    30  // Timespec, it returns a zero Timespec and ERANGE.
    31  func TimeToTimespec(t time.Time) (Timespec, error) {
    32  	sec := t.Unix()
    33  	nsec := int64(t.Nanosecond())
    34  	ts := setTimespec(sec, nsec)
    35  
    36  	// Currently all targets have either int32 or int64 for Timespec.Sec.
    37  	// If there were a new target with floating point type for it, we have
    38  	// to consider the rounding error.
    39  	if int64(ts.Sec) != sec {
    40  		return Timespec{}, ERANGE
    41  	}
    42  	return ts, nil
    43  }
    44  
    45  // TimevalToNsec converts a Timeval value into a number of nanoseconds
    46  // since the Unix epoch.
    47  func TimevalToNsec(tv Timeval) int64 { return int64(tv.Sec)*1e9 + int64(tv.Usec)*1e3 }
    48  
    49  // NsecToTimeval takes a number of nanoseconds since the Unix epoch
    50  // and returns the corresponding Timeval value.
    51  func NsecToTimeval(nsec int64) Timeval {
    52  	nsec += 999 // round up to microsecond
    53  	usec := nsec % 1e9 / 1e3
    54  	sec := nsec / 1e9
    55  	if usec < 0 {
    56  		usec += 1e6
    57  		sec--
    58  	}
    59  	return setTimeval(sec, usec)
    60  }
    61  
    62  // Unix returns ts as the number of seconds and nanoseconds elapsed since the
    63  // Unix epoch.
    64  func (ts *Timespec) Unix() (sec int64, nsec int64) {
    65  	return int64(ts.Sec), int64(ts.Nsec)
    66  }
    67  
    68  // Unix returns tv as the number of seconds and nanoseconds elapsed since the
    69  // Unix epoch.
    70  func (tv *Timeval) Unix() (sec int64, nsec int64) {
    71  	return int64(tv.Sec), int64(tv.Usec) * 1000
    72  }
    73  
    74  // Nano returns ts as the number of nanoseconds elapsed since the Unix epoch.
    75  func (ts *Timespec) Nano() int64 {
    76  	return int64(ts.Sec)*1e9 + int64(ts.Nsec)
    77  }
    78  
    79  // Nano returns tv as the number of nanoseconds elapsed since the Unix epoch.
    80  func (tv *Timeval) Nano() int64 {
    81  	return int64(tv.Sec)*1e9 + int64(tv.Usec)*1000
    82  }