1 // Copyright 2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
17 use sys_common::mul_div_u64;
20 const NANOS_PER_SEC: u64 = 1_000_000_000;
21 const INTERVALS_PER_SEC: u64 = NANOS_PER_SEC / 100;
23 #[derive(Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Debug)]
28 #[derive(Copy, Clone)]
29 pub struct SystemTime {
33 const INTERVALS_TO_UNIX_EPOCH: u64 = 11_644_473_600 * INTERVALS_PER_SEC;
35 pub const UNIX_EPOCH: SystemTime = SystemTime {
37 dwLowDateTime: INTERVALS_TO_UNIX_EPOCH as u32,
38 dwHighDateTime: (INTERVALS_TO_UNIX_EPOCH >> 32) as u32,
43 pub fn now() -> Instant {
44 let mut t = Instant { t: 0 };
46 c::QueryPerformanceCounter(&mut t.t)
51 pub fn sub_instant(&self, other: &Instant) -> Duration {
52 // Values which are +- 1 need to be considered as basically the same
53 // units in time due to various measurement oddities, according to
57 // https://msdn.microsoft.com/en-us/library/windows/desktop
58 // /dn553408%28v=vs.85%29.aspx#guidance
59 if other.t > self.t && other.t - self.t == 1 {
60 return Duration::new(0, 0)
62 let diff = (self.t as u64).checked_sub(other.t as u64)
63 .expect("specified instant was later than \
65 let nanos = mul_div_u64(diff, NANOS_PER_SEC, frequency() as u64);
66 Duration::new(nanos / NANOS_PER_SEC, (nanos % NANOS_PER_SEC) as u32)
69 pub fn add_duration(&self, other: &Duration) -> Instant {
70 let freq = frequency() as u64;
71 let t = other.as_secs().checked_mul(freq).and_then(|i| {
72 (self.t as u64).checked_add(i)
74 i.checked_add(mul_div_u64(other.subsec_nanos() as u64, freq,
76 }).expect("overflow when adding duration to time");
78 t: t as c::LARGE_INTEGER,
82 pub fn sub_duration(&self, other: &Duration) -> Instant {
83 let freq = frequency() as u64;
84 let t = other.as_secs().checked_mul(freq).and_then(|i| {
85 (self.t as u64).checked_sub(i)
87 i.checked_sub(mul_div_u64(other.subsec_nanos() as u64, freq,
89 }).expect("overflow when subtracting duration from time");
91 t: t as c::LARGE_INTEGER,
97 pub fn now() -> SystemTime {
99 let mut t: SystemTime = mem::zeroed();
100 c::GetSystemTimeAsFileTime(&mut t.t);
105 fn from_intervals(intervals: i64) -> SystemTime {
108 dwLowDateTime: intervals as c::DWORD,
109 dwHighDateTime: (intervals >> 32) as c::DWORD,
114 fn intervals(&self) -> i64 {
115 (self.t.dwLowDateTime as i64) | ((self.t.dwHighDateTime as i64) << 32)
118 pub fn sub_time(&self, other: &SystemTime) -> Result<Duration, Duration> {
119 let me = self.intervals();
120 let other = other.intervals();
122 Ok(intervals2dur((me - other) as u64))
124 Err(intervals2dur((other - me) as u64))
128 pub fn add_duration(&self, other: &Duration) -> SystemTime {
129 let intervals = self.intervals().checked_add(dur2intervals(other))
130 .expect("overflow when adding duration to time");
131 SystemTime::from_intervals(intervals)
134 pub fn sub_duration(&self, other: &Duration) -> SystemTime {
135 let intervals = self.intervals().checked_sub(dur2intervals(other))
136 .expect("overflow when subtracting from time");
137 SystemTime::from_intervals(intervals)
141 impl PartialEq for SystemTime {
142 fn eq(&self, other: &SystemTime) -> bool {
143 self.intervals() == other.intervals()
147 impl Eq for SystemTime {}
149 impl PartialOrd for SystemTime {
150 fn partial_cmp(&self, other: &SystemTime) -> Option<Ordering> {
151 Some(self.cmp(other))
155 impl Ord for SystemTime {
156 fn cmp(&self, other: &SystemTime) -> Ordering {
157 self.intervals().cmp(&other.intervals())
161 impl fmt::Debug for SystemTime {
162 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
163 f.debug_struct("SystemTime")
164 .field("intervals", &self.intervals())
169 impl From<c::FILETIME> for SystemTime {
170 fn from(t: c::FILETIME) -> SystemTime {
175 fn dur2intervals(d: &Duration) -> i64 {
176 d.as_secs().checked_mul(INTERVALS_PER_SEC).and_then(|i| {
177 i.checked_add(d.subsec_nanos() as u64 / 100)
178 }).expect("overflow when converting duration to intervals") as i64
181 fn intervals2dur(intervals: u64) -> Duration {
182 Duration::new(intervals / INTERVALS_PER_SEC,
183 ((intervals % INTERVALS_PER_SEC) * 100) as u32)
186 fn frequency() -> c::LARGE_INTEGER {
187 static mut FREQUENCY: c::LARGE_INTEGER = 0;
188 static ONCE: Once = Once::new();
192 cvt(c::QueryPerformanceFrequency(&mut FREQUENCY)).unwrap();