std: Add a Duration type

Taken from rust-chrono[1]. Needed for timers per #11189.
Experimental.

[1]: https://github.com/lifthrasiir/rust-chrono

2 files changed, 417 insertions, 0 deletions

diff --git a/src/libstd/duration.rs b/src/libstd/duration.rs
new file mode 100644
index 00000000000..7bc07d7acb6
--- /dev/null
+++ b/src/libstd/duration.rs
@@ -0,0 +1,415 @@
+// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Temporal quantification
+
+#![experimental]
+#![allow(missing_doc)] // FIXME
+
+use {fmt, num, i32};
+use option::{Option, Some, None};
+use result::{Result, Ok, Err};
+use ops::{Neg, Add, Sub, Mul, Div};
+use num::{CheckedAdd, ToPrimitive};
+
+pub static MIN_DAYS: i32 = i32::MIN;
+pub static MAX_DAYS: i32 = i32::MAX;
+
+static NANOS_PER_SEC: i32 = 1_000_000_000;
+static SECS_PER_DAY: i32 = 86400;
+
+macro_rules! earlyexit(
+    ($e:expr) => (match $e { Some(v) => v, None => return None })
+)
+
+/// ISO 8601 duration
+#[deriving(PartialEq, Eq, PartialOrd, Ord)]
+pub struct Duration {
+    days: i32,
+    secs: u32,
+    nanos: u32,
+}
+
+impl Duration {
+    pub fn new(days: i32, secs: i32, nanos: i32) -> Option<Duration> {
+        let (secs_, nanos) = div_mod_floor(nanos, NANOS_PER_SEC);
+        let secs = earlyexit!(secs.checked_add(&secs_));
+        let (days_, secs) = div_mod_floor(secs, SECS_PER_DAY);
+        let days = earlyexit!(days.checked_add(&days_).and_then(|v| v.to_i32()));
+        Some(Duration { days: days, secs: secs as u32, nanos: nanos as u32 })
+    }
+
+    #[inline]
+    pub fn weeks(weeks: i32) -> Duration {
+        Duration::days(weeks * 7)
+    }
+
+    #[inline]
+    pub fn days(days: i32) -> Duration {
+        let days = days.to_i32().expect("Duration::days out of bounds");
+        Duration { days: days, secs: 0, nanos: 0 }
+    }
+
+    #[inline]
+    pub fn hours(hours: i32) -> Duration {
+        let (days, hours) = div_mod_floor(hours, (SECS_PER_DAY / 3600));
+        let secs = hours * 3600;
+        Duration { secs: secs as u32, ..Duration::days(days) }
+    }
+
+    #[inline]
+    pub fn minutes(mins: i32) -> Duration {
+        let (days, mins) = div_mod_floor(mins, (SECS_PER_DAY / 60));
+        let secs = mins * 60;
+        Duration { secs: secs as u32, ..Duration::days(days) }
+    }
+
+    #[inline]
+    pub fn seconds(secs: i32) -> Duration {
+        let (days, secs) = div_mod_floor(secs, SECS_PER_DAY);
+        Duration { secs: secs as u32, ..Duration::days(days) }
+    }
+
+    #[inline]
+    pub fn milliseconds(millis: i32) -> Duration {
+        let (secs, millis) = div_mod_floor(millis, (NANOS_PER_SEC / 1_000_000));
+        let nanos = millis * 1_000_000;
+        Duration { nanos: nanos as u32, ..Duration::seconds(secs) }
+    }
+
+    #[inline]
+    pub fn microseconds(micros: i32) -> Duration {
+        let (secs, micros) = div_mod_floor(micros, (NANOS_PER_SEC / 1_000));
+        let nanos = micros * 1_000;
+        Duration { nanos: nanos as u32, ..Duration::seconds(secs) }
+    }
+
+    #[inline]
+    pub fn nanoseconds(nanos: i32) -> Duration {
+        let (secs, nanos) = div_mod_floor(nanos, NANOS_PER_SEC);
+        Duration { nanos: nanos as u32, ..Duration::seconds(secs) }
+    }
+
+    #[inline]
+    pub fn ndays(&self) -> i32 {
+        self.days as i32
+    }
+
+    #[inline]
+    pub fn nseconds(&self) -> u32 {
+        self.secs as u32
+    }
+
+    #[inline]
+    pub fn nnanoseconds(&self) -> u32 {
+        self.nanos as u32
+    }
+}
+
+impl num::Zero for Duration {
+    #[inline]
+    fn zero() -> Duration {
+        Duration { days: 0, secs: 0, nanos: 0 }
+    }
+
+    #[inline]
+    fn is_zero(&self) -> bool {
+        self.days == 0 && self.secs == 0 && self.nanos == 0
+    }
+}
+
+impl Neg<Duration> for Duration {
+    fn neg(&self) -> Duration {
+        // FIXME overflow (e.g. `-Duration::days(i32::MIN as i32)`)
+        let mut days = -(self.days as i32);
+        let mut secs = -(self.secs as i32);
+        let mut nanos = -(self.nanos as i32);
+        if nanos < 0 {
+            nanos += NANOS_PER_SEC;
+            secs -= 1;
+        }
+        if secs < 0 {
+            secs += SECS_PER_DAY;
+            days -= 1;
+        }
+        Duration { days: days as i32, secs: secs as u32, nanos: nanos as u32 }
+    }
+}
+
+impl Add<Duration,Duration> for Duration {
+    fn add(&self, rhs: &Duration) -> Duration {
+        let mut days = self.days + rhs.days;
+        let mut secs = self.secs + rhs.secs;
+        let mut nanos = self.nanos + rhs.nanos;
+        if nanos >= NANOS_PER_SEC as u32 {
+            nanos -= NANOS_PER_SEC as u32;
+            secs += 1;
+        }
+        if secs >= SECS_PER_DAY as u32 {
+            secs -= SECS_PER_DAY as u32;
+            days += 1;
+        }
+        Duration { days: days, secs: secs, nanos: nanos }
+    }
+}
+
+impl num::CheckedAdd for Duration {
+    fn checked_add(&self, rhs: &Duration) -> Option<Duration> {
+        let mut days = earlyexit!(self.days.checked_add(&rhs.days));
+        let mut secs = self.secs + rhs.secs;
+        let mut nanos = self.nanos + rhs.nanos;
+        if nanos >= NANOS_PER_SEC as u32 {
+            nanos -= NANOS_PER_SEC as u32;
+            secs += 1;
+        }
+        if secs >= SECS_PER_DAY as u32 {
+            secs -= SECS_PER_DAY as u32;
+            days = earlyexit!(days.checked_add(&1));
+        }
+        Some(Duration { days: days, secs: secs, nanos: nanos })
+    }
+}
+
+impl Sub<Duration,Duration> for Duration {
+    fn sub(&self, rhs: &Duration) -> Duration {
+        let mut days = self.days - rhs.days;
+        let mut secs = self.secs as i32 - rhs.secs as i32;
+        let mut nanos = self.nanos as i32 - rhs.nanos as i32;
+        if nanos < 0 {
+            nanos += NANOS_PER_SEC;
+            secs -= 1;
+        }
+        if secs < 0 {
+            secs += SECS_PER_DAY;
+            days -= 1;
+        }
+        Duration { days: days, secs: secs as u32, nanos: nanos as u32 }
+    }
+}
+
+impl num::CheckedSub for Duration {
+    fn checked_sub(&self, rhs: &Duration) -> Option<Duration> {
+        let mut days = earlyexit!(self.days.checked_sub(&rhs.days));
+        let mut secs = self.secs as i32 - rhs.secs as i32;
+        let mut nanos = self.nanos as i32 - rhs.nanos as i32;
+        if nanos < 0 {
+            nanos += NANOS_PER_SEC;
+            secs -= 1;
+        }
+        if secs < 0 {
+            secs += SECS_PER_DAY;
+            days = earlyexit!(days.checked_sub(&1));
+        }
+        Some(Duration { days: days, secs: secs as u32, nanos: nanos as u32 })
+    }
+}
+
+impl Mul<i32,Duration> for Duration {
+    fn mul(&self, rhs: &i32) -> Duration {
+        /// Given `0 <= y < limit <= 2^30`,
+        /// returns `(h,l)` such that `x * y = h * limit + l` where `0 <= l < limit`.
+        fn mul_i64_u32_limit(x: i64, y: u32, limit: u32) -> (i64,u32) {
+            let y = y as i64;
+            let limit = limit as i64;
+            let (xh, xl) = div_mod_floor_64(x, limit);
+            let (h, l) = (xh * y, xl * y);
+            let (h_, l) = div_rem_64(l, limit);
+            (h + h_, l as u32)
+        }
+
+        let rhs = *rhs as i64;
+        let (secs1, nanos) = mul_i64_u32_limit(rhs, self.nanos, NANOS_PER_SEC as u32);
+        let (days1, secs1) = div_mod_floor_64(secs1, (SECS_PER_DAY as i64));
+        let (days2, secs2) = mul_i64_u32_limit(rhs, self.secs, SECS_PER_DAY as u32);
+        let mut days = self.days as i64 * rhs + days1 + days2;
+        let mut secs = secs1 as u32 + secs2;
+        if secs >= SECS_PER_DAY as u32 {
+            secs -= 1;
+            days += 1;
+        }
+        Duration { days: days as i32, secs: secs, nanos: nanos }
+    }
+}
+
+impl Div<i32,Duration> for Duration {
+    fn div(&self, rhs: &i32) -> Duration {
+        let (rhs, days, secs, nanos) = if *rhs < 0 {
+            let negated = -*self;
+            (-*rhs as i64, negated.days as i64, negated.secs as i64, negated.nanos as i64)
+        } else {
+            (*rhs as i64, self.days as i64, self.secs as i64, self.nanos as i64)
+        };
+
+        let (days, carry) = div_mod_floor_64(days, rhs);
+        let secs = secs + carry * SECS_PER_DAY as i64;
+        let (secs, carry) = div_mod_floor_64(secs, rhs);
+        let nanos = nanos + carry * NANOS_PER_SEC as i64;
+        let nanos = nanos / rhs;
+        Duration { days: days as i32, secs: secs as u32, nanos: nanos as u32 }
+    }
+}
+
+impl fmt::Show for Duration {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let hasdate = self.days != 0;
+        let hastime = (self.secs != 0 || self.nanos != 0) || !hasdate;
+
+        try!('P'.fmt(f));
+        if hasdate {
+            // technically speaking the negative part is not the valid ISO 8601,
+            // but we need to print it anyway.
+            try!(write!(f, "{}D", self.days));
+        }
+        if hastime {
+            if self.nanos == 0 {
+                try!(write!(f, "T{}S", self.secs));
+            } else if self.nanos % 1_000_000 == 0 {
+                try!(write!(f, "T{},{:03}S", self.secs, self.nanos / 1_000_000));
+            } else if self.nanos % 1_000 == 0 {
+                try!(write!(f, "T{},{:06}S", self.secs, self.nanos / 1_000));
+            } else {
+                try!(write!(f, "T{},{:09}S", self.secs, self.nanos));
+            }
+        }
+        Ok(())
+    }
+}
+
+// Copied from libnum
+#[inline]
+fn div_mod_floor(this: i32, other: i32) -> (i32, i32) {
+    (div_floor(this, other), mod_floor(this, other))
+}
+
+#[inline]
+fn div_floor(this: i32, other: i32) -> i32 {
+    match div_rem(this, other) {
+        (d, r) if (r > 0 && other < 0)
+               || (r < 0 && other > 0) => d - 1,
+        (d, _)                         => d,
+    }
+}
+
+#[inline]
+fn mod_floor(this: i32, other: i32) -> i32 {
+    match this % other {
+        r if (r > 0 && other < 0)
+          || (r < 0 && other > 0) => r + other,
+        r                         => r,
+    }
+}
+
+#[inline]
+fn div_rem(this: i32, other: i32) -> (i32, i32) {
+    (this / other, this % other)
+}
+
+#[inline]
+fn div_mod_floor_64(this: i64, other: i64) -> (i64, i64) {
+    (div_floor_64(this, other), mod_floor_64(this, other))
+}
+
+#[inline]
+fn div_floor_64(this: i64, other: i64) -> i64 {
+    match div_rem_64(this, other) {
+        (d, r) if (r > 0 && other < 0)
+               || (r < 0 && other > 0) => d - 1,
+        (d, _)                         => d,
+    }
+}
+
+#[inline]
+fn mod_floor_64(this: i64, other: i64) -> i64 {
+    match this % other {
+        r if (r > 0 && other < 0)
+          || (r < 0 && other > 0) => r + other,
+        r                         => r,
+    }
+}
+
+#[inline]
+fn div_rem_64(this: i64, other: i64) -> (i64, i64) {
+    (this / other, this % other)
+}
+
+
+#[cfg(test)]
+mod tests {
+    use super::{Duration, MIN_DAYS, MAX_DAYS};
+    use i32;
+    use num::{CheckedAdd, CheckedSub, Zero};
+    use to_string::ToString;
+
+    fn zero() -> Duration { Zero::zero() }
+
+    #[test]
+    fn test_duration() {
+        assert!(zero() != Duration::seconds(1));
+        assert_eq!(Duration::seconds(1) + Duration::seconds(2), Duration::seconds(3));
+        assert_eq!(Duration::seconds(86399) + Duration::seconds(4),
+                   Duration::days(1) + Duration::seconds(3));
+        assert_eq!(Duration::days(10) - Duration::seconds(1000), Duration::seconds(863000));
+        assert_eq!(Duration::days(10) - Duration::seconds(1000000), Duration::seconds(-136000));
+        assert_eq!(Duration::days(2) + Duration::seconds(86399) + Duration::nanoseconds(1234567890),
+                   Duration::days(3) + Duration::nanoseconds(234567890));
+        assert_eq!(-Duration::days(3), Duration::days(-3));
+        assert_eq!(-(Duration::days(3) + Duration::seconds(70)),
+                   Duration::days(-4) + Duration::seconds(86400-70));
+    }
+
+    #[test]
+    fn test_duration_checked_ops() {
+        assert_eq!(Duration::days(MAX_DAYS).checked_add(&Duration::seconds(86399)),
+                   Some(Duration::days(MAX_DAYS - 1) + Duration::seconds(86400+86399)));
+        assert!(Duration::days(MAX_DAYS).checked_add(&Duration::seconds(86400)).is_none());
+
+        assert_eq!(Duration::days(MIN_DAYS).checked_sub(&Duration::seconds(0)),
+                   Some(Duration::days(MIN_DAYS)));
+        assert!(Duration::days(MIN_DAYS).checked_sub(&Duration::seconds(1)).is_none());
+    }
+
+    #[test]
+    fn test_duration_mul() {
+        assert_eq!(zero() * i32::MAX, zero());
+        assert_eq!(zero() * i32::MIN, zero());
+        assert_eq!(Duration::nanoseconds(1) * 0, zero());
+        assert_eq!(Duration::nanoseconds(1) * 1, Duration::nanoseconds(1));
+        assert_eq!(Duration::nanoseconds(1) * 1_000_000_000, Duration::seconds(1));
+        assert_eq!(Duration::nanoseconds(1) * -1_000_000_000, -Duration::seconds(1));
+        assert_eq!(-Duration::nanoseconds(1) * 1_000_000_000, -Duration::seconds(1));
+        assert_eq!(Duration::nanoseconds(30) * 333_333_333,
+                   Duration::seconds(10) - Duration::nanoseconds(10));
+        assert_eq!((Duration::nanoseconds(1) + Duration::seconds(1) + Duration::days(1)) * 3,
+                   Duration::nanoseconds(3) + Duration::seconds(3) + Duration::days(3));
+    }
+
+    #[test]
+    fn test_duration_div() {
+        assert_eq!(zero() / i32::MAX, zero());
+        assert_eq!(zero() / i32::MIN, zero());
+        assert_eq!(Duration::nanoseconds(123_456_789) / 1, Duration::nanoseconds(123_456_789));
+        assert_eq!(Duration::nanoseconds(123_456_789) / -1, -Duration::nanoseconds(123_456_789));
+        assert_eq!(-Duration::nanoseconds(123_456_789) / -1, Duration::nanoseconds(123_456_789));
+        assert_eq!(-Duration::nanoseconds(123_456_789) / 1, -Duration::nanoseconds(123_456_789));
+    }
+
+    #[test]
+    fn test_duration_fmt() {
+        assert_eq!(zero().to_string(), "PT0S".to_string());
+        assert_eq!(Duration::days(42).to_string(), "P42D".to_string());
+        assert_eq!(Duration::days(-42).to_string(), "P-42D".to_string());
+        assert_eq!(Duration::seconds(42).to_string(), "PT42S".to_string());
+        assert_eq!(Duration::milliseconds(42).to_string(), "PT0,042S".to_string());
+        assert_eq!(Duration::microseconds(42).to_string(), "PT0,000042S".to_string());
+        assert_eq!(Duration::nanoseconds(42).to_string(), "PT0,000000042S".to_string());
+        assert_eq!((Duration::days(7) + Duration::milliseconds(6543)).to_string(),
+                   "P7DT6,543S".to_string());
+    }
+}
diff --git a/src/libstd/lib.rs b/src/libstd/lib.rs
index 20fc7efeb57..f2db4944de4 100644
--- a/src/libstd/lib.rs
+++ b/src/libstd/lib.rs
@@ -233,6 +233,8 @@ pub mod ascii;
 #[cfg(not(test))]
 pub mod gc;
 
+pub mod duration;
+
 /* Common traits */
 
 pub mod from_str;