From 20ad931bf337db2efd25e6571e322d31b5b83877 Mon Sep 17 00:00:00 2001
From: Brendan Zabarauskas <bjzaba@yahoo.com.au>
Date: Mon, 29 Apr 2013 16:02:43 +1000
Subject: [PATCH] Rename 'divisible_by' method to 'is_multiple_of', add tests
 for 'is_odd' and 'is_even'

---
 src/libcore/num/int-template.rs  | 40 ++++++++++++++++++++++++++++++--
 src/libcore/num/num.rs           |  3 ++-
 src/libcore/num/uint-template.rs | 29 +++++++++++++++++++++--
 src/libstd/num/bigint.rs         |  4 ++--
 4 files changed, 69 insertions(+), 7 deletions(-)

diff --git a/src/libcore/num/int-template.rs b/src/libcore/num/int-template.rs
index 08df820a73d..ec38a32c039 100644
--- a/src/libcore/num/int-template.rs
+++ b/src/libcore/num/int-template.rs
@@ -406,11 +406,11 @@ impl Integer for T {
 
     /// Returns `true` if the number can be divided by `other` without leaving a remainder
     #[inline(always)]
-    fn divisible_by(&self, other: &T) -> bool { *self % *other == 0 }
+    fn is_multiple_of(&self, other: &T) -> bool { *self % *other == 0 }
 
     /// Returns `true` if the number is divisible by `2`
     #[inline(always)]
-    fn is_even(&self) -> bool { self.divisible_by(&2) }
+    fn is_even(&self) -> bool { self.is_multiple_of(&2) }
 
     /// Returns `true` if the number is not divisible by `2`
     #[inline(always)]
@@ -682,6 +682,42 @@ mod tests {
         assert_eq!(-(0b11 as T) - (1 as T), (0b11 as T).not());
     }
 
+    #[test]
+    fn test_multiple_of() {
+        assert!((6 as T).is_multiple_of(&(6 as T)));
+        assert!((6 as T).is_multiple_of(&(3 as T)));
+        assert!((6 as T).is_multiple_of(&(1 as T)));
+        assert!((-8 as T).is_multiple_of(&(4 as T)));
+        assert!((8 as T).is_multiple_of(&(-1 as T)));
+        assert!((-8 as T).is_multiple_of(&(-2 as T)));
+    }
+
+    #[test]
+    fn test_even() {
+        assert_eq!((-4 as T).is_even(), true);
+        assert_eq!((-3 as T).is_even(), false);
+        assert_eq!((-2 as T).is_even(), true);
+        assert_eq!((-1 as T).is_even(), false);
+        assert_eq!((0 as T).is_even(), true);
+        assert_eq!((1 as T).is_even(), false);
+        assert_eq!((2 as T).is_even(), true);
+        assert_eq!((3 as T).is_even(), false);
+        assert_eq!((4 as T).is_even(), true);
+    }
+
+    #[test]
+    fn test_odd() {
+        assert_eq!((-4 as T).is_odd(), false);
+        assert_eq!((-3 as T).is_odd(), true);
+        assert_eq!((-2 as T).is_odd(), false);
+        assert_eq!((-1 as T).is_odd(), true);
+        assert_eq!((0 as T).is_odd(), false);
+        assert_eq!((1 as T).is_odd(), true);
+        assert_eq!((2 as T).is_odd(), false);
+        assert_eq!((3 as T).is_odd(), true);
+        assert_eq!((4 as T).is_odd(), false);
+    }
+
     #[test]
     fn test_bitcount() {
         assert_eq!((0b010101 as T).population_count(), 3);
diff --git a/src/libcore/num/num.rs b/src/libcore/num/num.rs
index 6fbc2985952..3e43ebfef12 100644
--- a/src/libcore/num/num.rs
+++ b/src/libcore/num/num.rs
@@ -85,7 +85,8 @@ pub trait Integer: Num
 
     fn gcd(&self, other: &Self) -> Self;
     fn lcm(&self, other: &Self) -> Self;
-    fn divisible_by(&self, other: &Self) -> bool;
+
+    fn is_multiple_of(&self, other: &Self) -> bool;
     fn is_even(&self) -> bool;
     fn is_odd(&self) -> bool;
 }
diff --git a/src/libcore/num/uint-template.rs b/src/libcore/num/uint-template.rs
index af64660ad0c..3dfdd22c42d 100644
--- a/src/libcore/num/uint-template.rs
+++ b/src/libcore/num/uint-template.rs
@@ -238,11 +238,11 @@ impl Integer for T {
 
     /// Returns `true` if the number can be divided by `other` without leaving a remainder
     #[inline(always)]
-    fn divisible_by(&self, other: &T) -> bool { *self % *other == 0 }
+    fn is_multiple_of(&self, other: &T) -> bool { *self % *other == 0 }
 
     /// Returns `true` if the number is divisible by `2`
     #[inline(always)]
-    fn is_even(&self) -> bool { self.divisible_by(&2) }
+    fn is_even(&self) -> bool { self.is_multiple_of(&2) }
 
     /// Returns `true` if the number is not divisible by `2`
     #[inline(always)]
@@ -415,6 +415,31 @@ mod tests {
         assert_eq!((99 as T).lcm(&17), 1683 as T);
     }
 
+    #[test]
+    fn test_multiple_of() {
+        assert!((6 as T).is_multiple_of(&(6 as T)));
+        assert!((6 as T).is_multiple_of(&(3 as T)));
+        assert!((6 as T).is_multiple_of(&(1 as T)));
+    }
+
+    #[test]
+    fn test_even() {
+        assert_eq!((0 as T).is_even(), true);
+        assert_eq!((1 as T).is_even(), false);
+        assert_eq!((2 as T).is_even(), true);
+        assert_eq!((3 as T).is_even(), false);
+        assert_eq!((4 as T).is_even(), true);
+    }
+
+    #[test]
+    fn test_odd() {
+        assert_eq!((0 as T).is_odd(), false);
+        assert_eq!((1 as T).is_odd(), true);
+        assert_eq!((2 as T).is_odd(), false);
+        assert_eq!((3 as T).is_odd(), true);
+        assert_eq!((4 as T).is_odd(), false);
+    }
+
     #[test]
     fn test_bitwise() {
         assert_eq!(0b1110 as T, (0b1100 as T).bitor(&(0b1010 as T)));
diff --git a/src/libstd/num/bigint.rs b/src/libstd/num/bigint.rs
index 3ea94eababb..e97b3b5eeec 100644
--- a/src/libstd/num/bigint.rs
+++ b/src/libstd/num/bigint.rs
@@ -428,7 +428,7 @@ impl Integer for BigUint {
 
     /// Returns `true` if the number can be divided by `other` without leaving a remainder
     #[inline(always)]
-    fn divisible_by(&self, other: &BigUint) -> bool { (*self % *other).is_zero() }
+    fn is_multiple_of(&self, other: &BigUint) -> bool { (*self % *other).is_zero() }
 
     /// Returns `true` if the number is divisible by `2`
     #[inline(always)]
@@ -973,7 +973,7 @@ impl Integer for BigInt {
 
     /// Returns `true` if the number can be divided by `other` without leaving a remainder
     #[inline(always)]
-    fn divisible_by(&self, other: &BigInt) -> bool { self.data.divisible_by(&other.data) }
+    fn is_multiple_of(&self, other: &BigInt) -> bool { self.data.is_multiple_of(&other.data) }
 
     /// Returns `true` if the number is divisible by `2`
     #[inline(always)]