bjoernager/rust
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Add checked_sub for Instant and SystemTime

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This commit is contained in:
Linus Färnstrand 2018-12-10 23:55:53 +01:00
parent 13f0463a19
commit f5a99c321b
6 changed files with 83 additions and 87 deletions
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48
src/libstd/sys/unix/time.rs
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@ -64,27 +64,25 @@ impl Timespec {
})
}
fn sub_duration(&self, other: &Duration) -> Timespec {
fn checked_sub_duration(&self, other: &Duration) -> Option<Timespec> {
let mut secs = other
.as_secs()
.try_into() // <- target type would be `libc::time_t`
.ok()
.and_then(|secs| self.t.tv_sec.checked_sub(secs))
.expect("overflow when subtracting duration from time");
.and_then(|secs| self.t.tv_sec.checked_sub(secs))?;
// Similar to above, nanos can't overflow.
let mut nsec = self.t.tv_nsec as i32 - other.subsec_nanos() as i32;
if nsec < 0 {
nsec += NSEC_PER_SEC as i32;
secs = secs.checked_sub(1).expect("overflow when subtracting \
duration from time");
secs = secs.checked_sub(1)?;
}
Timespec {
Some(Timespec {
t: libc::timespec {
tv_sec: secs,
tv_nsec: nsec as _,
},
}
})
}
}
@ -162,14 +160,15 @@ mod inner {
}
pub fn checked_add_duration(&self, other: &Duration) -> Option<Instant> {
checked_dur2intervals(other)?.checked_add(self.t).map(|t| Instant {t})
Some(Instant {
t: self.t.checked_add(checked_dur2intervals(other)?)?,
})
}
pub fn sub_duration(&self, other: &Duration) -> Instant {
Instant {
t: self.t.checked_sub(dur2intervals(other))
.expect("overflow when subtracting duration from instant"),
}
pub fn checked_sub_duration(&self, other: &Duration) -> Option<Instant> {
Some(Instant {
t: self.t.checked_sub(checked_dur2intervals(other)?)?,
})
}
}
@ -193,11 +192,11 @@ mod inner {
}
pub fn checked_add_duration(&self, other: &Duration) -> Option<SystemTime> {
self.t.checked_add_duration(other).map(|t| SystemTime { t })
Some(SystemTime { t: self.t.checked_add_duration(other)? })
}
pub fn sub_duration(&self, other: &Duration) -> SystemTime {
SystemTime { t: self.t.sub_duration(other) }
pub fn checked_sub_duration(&self, other: &Duration) -> Option<SystemTime> {
Some(SystemTime { t: self.t.checked_sub_duration(other)? })
}
}
@ -225,11 +224,6 @@ mod inner {
}
}
fn dur2intervals(dur: &Duration) -> u64 {
checked_dur2intervals(dur)
.expect("overflow converting duration to nanoseconds")
}
fn checked_dur2intervals(dur: &Duration) -> Option<u64> {
let nanos = dur.as_secs()
.checked_mul(NSEC_PER_SEC)?
@ -294,11 +288,11 @@ mod inner {
}
pub fn checked_add_duration(&self, other: &Duration) -> Option<Instant> {
self.t.checked_add_duration(other).map(|t| Instant { t })
Some(Instant { t: self.t.checked_add_duration(other)? })
}
pub fn sub_duration(&self, other: &Duration) -> Instant {
Instant { t: self.t.sub_duration(other) }
pub fn checked_sub_duration(&self, other: &Duration) -> Option<Instant> {
Some(Instant { t: self.t.checked_sub_duration(other)? })
}
}
@ -322,11 +316,11 @@ mod inner {
}
pub fn checked_add_duration(&self, other: &Duration) -> Option<SystemTime> {
self.t.checked_add_duration(other).map(|t| SystemTime { t })
Some(SystemTime { t: self.t.checked_add_duration(other)? })
}
pub fn sub_duration(&self, other: &Duration) -> SystemTime {
SystemTime { t: self.t.sub_duration(other) }
pub fn checked_sub_duration(&self, other: &Duration) -> Option<SystemTime> {
Some(SystemTime { t: self.t.checked_sub_duration(other)? })
}
}