0.1.2: no more `num` dependency, multidispatched addition.

- `num` dependency is gone. It was only used for floored division
  and it is not hard to copy only that portion from num.
- `Duration + Date` (or so) was blocked by rust-lang/rust#7590,
  which has been subsequently fixed.
- Removed unused `unsafe` checks.

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "chrono"
-version = "0.1.1"
+version = "0.1.2"
 authors = ["Kang Seonghoon <public+rust@mearie.org>"]
 
 description = "Date and time library for Rust"
@@ -13,9 +13,6 @@ license = "MIT/Apache-2.0"
 [lib]
 name = "chrono"
 
-[dependencies.num]
-git = "https://github.com/rust-lang/num"
-
 [dependencies.time]
 git = "https://github.com/rust-lang/time"
 

src/date.rs

@@ -263,13 +263,10 @@ impl<Off:Offset> Add<Duration,Date<Off>> for Date<Off> {
     }
 }
 
-/*
-// Rust issue #7590, the current coherence checker can't handle multiple Add impls
 impl<Off:Offset> Add<Date<Off>,Date<Off>> for Duration {
     #[inline]
     fn add(&self, rhs: &Date<Off>) -> Date<Off> { rhs.add(self) }
 }
-*/
 
 impl<Off:Offset, Off2:Offset> Sub<Date<Off2>,Duration> for Date<Off> {
     fn sub(&self, rhs: &Date<Off2>) -> Duration {

src/datetime.rs

@@ -185,13 +185,10 @@ impl<Off:Offset> Add<Duration,DateTime<Off>> for DateTime<Off> {
     }
 }
 
-/*
-// Rust issue #7590, the current coherence checker can't handle multiple Add impls
 impl<Off:Offset> Add<DateTime<Off>,DateTime<Off>> for Duration {
     #[inline]
     fn add(&self, rhs: &DateTime<Off>) -> DateTime<Off> { rhs.add(self) }
 }
-*/
 
 impl<Off:Offset, Off2:Offset> Sub<DateTime<Off2>,Duration> for DateTime<Off> {
     fn sub(&self, rhs: &DateTime<Off2>) -> Duration {

src/div.rs

@@ -0,0 +1,70 @@
+// This is a part of rust-chrono.
+// Copyright (c) 2014, Kang Seonghoon.
+// Copyright 2013-2014 The Rust Project Developers.
+// See README.md and LICENSE.txt for details.
+
+//! Integer division utilities. (Shamelessly copied from [num](https://github.com/rust-lang/num/))
+
+// Algorithm from [Daan Leijen. _Division and Modulus for Computer Scientists_,
+// December 2001](http://research.microsoft.com/pubs/151917/divmodnote-letter.pdf)
+
+use std::num::Int;
+
+/// Same as `(a / b, a % b)`.
+#[inline]
+pub fn div_rem<T: Int>(a: T, b: T) -> (T, T) {
+    (a / b, a % b)
+}
+
+/// Same as `let (q, r) = div_mod_floor(a, b); r`.
+#[inline]
+pub fn mod_floor<T: Int>(a: T, b: T) -> T {
+    let zero = Int::zero();
+    match a % b {
+        r if (r > zero && b < zero) || (r < zero && b > zero) => r + b,
+        r                                                     => r,
+    }
+}
+
+/// Calculates a floored integer quotient and modulo.
+#[inline]
+pub fn div_mod_floor<T: Int>(a: T, b: T) -> (T, T) {
+    let zero = Int::zero();
+    let one = Int::one();
+    match (a / b, a % b) {
+        (d, r) if (r > zero && b < zero) || (r < zero && b > zero) => (d - one, r + b),
+        (d, r)                                                     => (d, r),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{mod_floor, div_mod_floor};
+
+    #[test]
+    fn test_mod_floor() {
+        assert_eq!(mod_floor( 8i,  3),  2);
+        assert_eq!(mod_floor( 8i, -3), -1);
+        assert_eq!(mod_floor(-8i,  3),  1);
+        assert_eq!(mod_floor(-8i, -3), -2);
+
+        assert_eq!(mod_floor( 1i,  2),  1);
+        assert_eq!(mod_floor( 1i, -2), -1);
+        assert_eq!(mod_floor(-1i,  2),  1);
+        assert_eq!(mod_floor(-1i, -2), -1);
+    }
+
+    #[test]
+    fn test_div_mod_floor() {
+        assert_eq!(div_mod_floor( 8i,  3), ( 2,  2));
+        assert_eq!(div_mod_floor( 8i, -3), (-3, -1));
+        assert_eq!(div_mod_floor(-8i,  3), (-3,  1));
+        assert_eq!(div_mod_floor(-8i, -3), ( 2, -2));
+
+        assert_eq!(div_mod_floor( 1i,  2), ( 0,  1));
+        assert_eq!(div_mod_floor( 1i, -2), (-1, -1));
+        assert_eq!(div_mod_floor(-1i,  2), (-1,  1));
+        assert_eq!(div_mod_floor(-1i, -2), ( 0, -1));
+    }
+}
+

src/lib.rs

@@ -13,7 +13,6 @@ Experimental date and time handling for Rust.
 #![feature(macro_rules)]
 #![deny(missing_docs)]
 
-extern crate num;
 extern crate "time" as stdtime;
 
 pub use duration::Duration;
@@ -26,6 +25,7 @@ pub use date::Date;
 pub use time::Time;
 pub use datetime::DateTime;
 
+mod div;
 pub mod duration {
     //! ISO 8601 duration.
     //!

src/naive/date.rs

@@ -8,9 +8,9 @@
 
 use std::fmt;
 use std::num::Int;
-use num::Integer;
 
 use {Weekday, Datelike};
+use div::div_mod_floor;
 use duration::Duration;
 use naive::time::NaiveTime;
 use naive::datetime::NaiveDateTime;
@@ -148,9 +148,9 @@ impl NaiveDate {
     /// Returns `None` on the out-of-range date.
     pub fn from_num_days_from_ce_opt(days: i32) -> Option<NaiveDate> {
         let days = days + 365; // make January 1, 1 BCE equal to day 0
-        let (year_div_400, cycle) = days.div_mod_floor(&146097);
+        let (year_div_400, cycle) = div_mod_floor(days, 146097);
         let (year_mod_400, ordinal) = internals::cycle_to_yo(cycle as u32);
-        let flags = unsafe { YearFlags::from_year_mod_400(year_mod_400 as i32) };
+        let flags = YearFlags::from_year_mod_400(year_mod_400 as i32);
         NaiveDate::from_of(year_div_400 * 400 + year_mod_400 as i32,
                            Of::new(ordinal, flags))
     }
@@ -382,33 +382,30 @@ impl Add<Duration,NaiveDate> for NaiveDate {
         // TODO overflow currently fails
 
         let year = self.year();
-        let (mut year_div_400, year_mod_400) = year.div_mod_floor(&400);
+        let (mut year_div_400, year_mod_400) = div_mod_floor(year, 400);
         let cycle = internals::yo_to_cycle(year_mod_400 as u32, self.of().ordinal());
         let cycle = (cycle as i32).checked_add(rhs.num_days().to_i32().unwrap()).unwrap();
-        let (cycle_div_400y, cycle) = cycle.div_mod_floor(&146097);
+        let (cycle_div_400y, cycle) = div_mod_floor(cycle, 146097);
         year_div_400 += cycle_div_400y;
 
         let (year_mod_400, ordinal) = internals::cycle_to_yo(cycle as u32);
-        let flags = unsafe { YearFlags::from_year_mod_400(year_mod_400 as i32) };
+        let flags = YearFlags::from_year_mod_400(year_mod_400 as i32);
         NaiveDate::from_of(year_div_400 * 400 + year_mod_400 as i32,
                            Of::new(ordinal, flags)).unwrap()
     }
 }
 
-/*
-// Rust issue #7590, the current coherence checker can't handle multiple Add impls
 impl Add<NaiveDate,NaiveDate> for Duration {
     #[inline]
     fn add(&self, rhs: &NaiveDate) -> NaiveDate { rhs.add(self) }
 }
-*/
 
 impl Sub<NaiveDate,Duration> for NaiveDate {
     fn sub(&self, rhs: &NaiveDate) -> Duration {
         let year1 = self.year();
         let year2 = rhs.year();
-        let (year1_div_400, year1_mod_400) = year1.div_mod_floor(&400);
+        let (year1_div_400, year1_mod_400) = div_mod_floor(year1, 400);
-        let (year2_div_400, year2_mod_400) = year2.div_mod_floor(&400);
+        let (year2_div_400, year2_mod_400) = div_mod_floor(year2, 400);
         let cycle1 = internals::yo_to_cycle(year1_mod_400 as u32, self.of().ordinal()) as i64;
         let cycle2 = internals::yo_to_cycle(year2_mod_400 as u32, rhs.of().ordinal()) as i64;
         Duration::days((year1_div_400 as i64 - year2_div_400 as i64) * 146097 + (cycle1 - cycle2))
@@ -698,7 +695,7 @@ mod tests {
             let lhs = NaiveDate::from_ymd(y1, m1, d1);
             let sum = NaiveDate::from_ymd(y, m, d);
             assert_eq!(lhs + rhs, sum);
-            //assert_eq!(rhs + lhs, sum);
+            assert_eq!(rhs + lhs, sum);
         }
 
         check((2014, 1, 1), Duration::zero(), (2014, 1, 1));
@@ -780,8 +777,8 @@ mod tests {
 #[allow(dead_code)] // some internal methods have been left for consistency
 mod internals {
     use std::{i32, num, fmt};
-    use num::Integer;
     use Weekday;
+    use div::{div_rem, mod_floor};
 
     /// The internal date representation. This also includes the packed `Mdf` value.
     pub type DateImpl = i32;
@@ -855,7 +852,7 @@ mod internals {
     ];
 
     pub fn cycle_to_yo(cycle: u32) -> (u32, u32) {
-        let (mut year_mod_400, mut ordinal0) = cycle.div_rem(&365);
+        let (mut year_mod_400, mut ordinal0) = div_rem(cycle, 365);
         let delta = YEAR_DELTAS[year_mod_400 as uint] as u32;
         if ordinal0 < delta {
             year_mod_400 -= 1;
@@ -873,12 +870,12 @@ mod internals {
     impl YearFlags {
         #[inline]
         pub fn from_year(year: i32) -> YearFlags {
-            let year = year.mod_floor(&400);
+            let year = mod_floor(year, 400);
-            unsafe { YearFlags::from_year_mod_400(year) }
+            YearFlags::from_year_mod_400(year)
         }
 
         #[inline]
-        pub unsafe fn from_year_mod_400(year: i32) -> YearFlags {
+        pub fn from_year_mod_400(year: i32) -> YearFlags {
             YEAR_TO_FLAGS[year as uint]
         }
 

src/naive/datetime.rs

@@ -8,9 +8,9 @@
 
 use std::fmt;
 use std::num::Int;
-use num::Integer;
 
 use {Weekday, Timelike, Datelike};
+use div::div_mod_floor;
 use duration::Duration;
 use naive::time::NaiveTime;
 use naive::date::NaiveDate;
@@ -49,7 +49,7 @@ impl NaiveDateTime {
     /// Returns `None` on the out-of-range number of seconds and/or invalid nanosecond.
     #[inline]
     pub fn from_num_seconds_from_unix_epoch_opt(secs: i64, nsecs: u32) -> Option<NaiveDateTime> {
-        let (days, secs) = secs.div_mod_floor(&86400);
+        let (days, secs) = div_mod_floor(secs, 86400);
         let date = days.to_i32().and_then(|days| days.checked_add(719163))
                                 .and_then(|days_ce| NaiveDate::from_num_days_from_ce_opt(days_ce));
         let time = NaiveTime::from_num_seconds_from_midnight_opt(secs as u32, nsecs);
@@ -183,13 +183,10 @@ impl Add<Duration,NaiveDateTime> for NaiveDateTime {
     }
 }
 
-/*
-// Rust issue #7590, the current coherence checker can't handle multiple Add impls
 impl Add<NaiveDateTime,NaiveDateTime> for Duration {
     #[inline]
     fn add(&self, rhs: &NaiveDateTime) -> NaiveDateTime { rhs.add(self) }
 }
-*/
 
 impl Sub<NaiveDateTime,Duration> for NaiveDateTime {
     fn sub(&self, rhs: &NaiveDateTime) -> Duration {

src/naive/time.rs

@@ -8,9 +8,9 @@
 
 use std::fmt;
 use std::num::Int;
-use num::Integer;
 
 use Timelike;
+use div::div_mod_floor;
 use offset::Offset;
 use duration::Duration;
 use format::DelayedFormat;
@@ -126,8 +126,8 @@ impl NaiveTime {
 
     /// Returns a triple of the hour, minute and second numbers.
     fn hms(&self) -> (u32, u32, u32) {
-        let (mins, sec) = self.secs.div_mod_floor(&60);
+        let (mins, sec) = div_mod_floor(self.secs, 60);
-        let (hour, min) = mins.div_mod_floor(&60);
+        let (hour, min) = div_mod_floor(mins, 60);
         (hour, min, sec)
     }
 }
@@ -190,13 +190,10 @@ impl Add<Duration,NaiveTime> for NaiveTime {
     }
 }
 
-/*
-// Rust issue #7590, the current coherence checker can't handle multiple Add impls
 impl Add<NaiveTime,NaiveTime> for Duration {
     #[inline]
     fn add(&self, rhs: &NaiveTime) -> NaiveTime { rhs.add(self) }
 }
-*/
 
 impl Sub<NaiveTime,Duration> for NaiveTime {
     fn sub(&self, rhs: &NaiveTime) -> Duration {
@@ -303,7 +300,7 @@ mod tests {
     fn test_time_add() {
         fn check(lhs: NaiveTime, rhs: Duration, sum: NaiveTime) {
             assert_eq!(lhs + rhs, sum);
-            //assert_eq!(rhs + lhs, sum);
+            assert_eq!(rhs + lhs, sum);
         }
 
         let hmsm = |h,m,s,mi| NaiveTime::from_hms_milli(h, m, s, mi);

src/offset.rs

@@ -9,9 +9,9 @@
 use std::fmt;
 use std::str::MaybeOwned;
 use stdtime;
-use num::Integer;
 
 use {Weekday, Datelike, Timelike};
+use div::div_mod_floor;
 use duration::Duration;
 use naive::date::NaiveDate;
 use naive::time::NaiveTime;
@@ -365,8 +365,8 @@ impl fmt::Show for FixedOffset {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         let offset = self.local_minus_utc;
         let (sign, offset) = if offset < 0 {('-', -offset)} else {('+', offset)};
-        let (mins, sec) = offset.div_mod_floor(&60);
+        let (mins, sec) = div_mod_floor(offset, 60);
-        let (hour, min) = mins.div_mod_floor(&60);
+        let (hour, min) = div_mod_floor(mins, 60);
         if sec == 0 {
             write!(f, "{}{:02}:{:02}", sign, hour, min)
         } else {

src/time.rs

@@ -113,13 +113,10 @@ impl<Off:Offset> Add<Duration,Time<Off>> for Time<Off> {
     }
 }
 
-/*
-// Rust issue #7590, the current coherence checker can't handle multiple Add impls
 impl<Off:Offset> Add<Time<Off>,Time<Off>> for Duration {
     #[inline]
     fn add(&self, rhs: &Time<Off>) -> Time<Off> { rhs.add(self) }
 }
-*/
 
 impl<Off:Offset, Off2:Offset> Sub<Time<Off2>,Duration> for Time<Off> {
     fn sub(&self, rhs: &Time<Off2>) -> Duration {