Create UnsignedInt trait and deprecate free functions

src/libarena/lib.rs

@@ -38,7 +38,7 @@ use std::cmp;
 use std::intrinsics::{TyDesc, get_tydesc};
 use std::intrinsics;
 use std::mem;
-use std::num;
+use std::num::UnsignedInt;
 use std::ptr;
 use std::rc::Rc;
 use std::rt::heap::{allocate, deallocate};
@@ -187,7 +187,7 @@ impl Arena {
         self.chunks.borrow_mut().push(self.copy_head.borrow().clone());
 
         *self.copy_head.borrow_mut() =
-            chunk(num::next_power_of_two(new_min_chunk_size + 1u), true);
+            chunk((new_min_chunk_size + 1u).next_power_of_two(), true);
 
         return self.alloc_copy_inner(n_bytes, align);
     }
@@ -228,7 +228,7 @@ impl Arena {
         self.chunks.borrow_mut().push(self.head.borrow().clone());
 
         *self.head.borrow_mut() =
-            chunk(num::next_power_of_two(new_min_chunk_size + 1u), false);
+            chunk((new_min_chunk_size + 1u).next_power_of_two(), false);
 
         return self.alloc_noncopy_inner(n_bytes, align);
     }

src/libcollections/vec.rs

@@ -21,7 +21,7 @@ use core::default::Default;
 use core::fmt;
 use core::kinds::marker::{ContravariantLifetime, InvariantType};
 use core::mem;
-use core::num;
+use core::num::UnsignedInt;
 use core::ops;
 use core::ptr;
 use core::raw::Slice as RawSlice;
@@ -605,7 +605,7 @@ impl<T> Vec<T> {
                 None => panic!("Vec::reserve: `uint` overflow"),
                 // if the checked_add
                 Some(new_cap) => {
-                    let amort_cap = num::next_power_of_two(new_cap);
+                    let amort_cap = new_cap.next_power_of_two();
                     // next_power_of_two will overflow to exactly 0 for really big capacities
                     if amort_cap == 0 {
                         self.grow_capacity(new_cap);

src/libcore/num/mod.rs

@@ -621,39 +621,46 @@ int_cast_impl!(i64, u64)
 #[cfg(target_word_size = "32")] int_cast_impl!(int, u32)
 #[cfg(target_word_size = "64")] int_cast_impl!(int, u64)
 
-/// Returns the smallest power of 2 greater than or equal to `n`.
-#[inline]
-pub fn next_power_of_two<T: Unsigned + Int>(n: T) -> T {
-    let halfbits = size_of::<T>() * 4;
-    let mut tmp: T = n - one();
-    let mut shift = 1u;
-    while shift <= halfbits {
-        tmp = tmp | (tmp >> shift);
-        shift = shift << 1u;
+/// Unsigned integers
+pub trait UnsignedInt: Int {
+    /// Returns `true` iff `self == 2^k` for some `k`.
+    fn is_power_of_two(self) -> bool {
+        (self - one()) & self == zero()
+    }
+
+    /// Returns the smallest power of two greater than or equal to `self`.
+    #[inline]
+    fn next_power_of_two(self) -> Self {
+        let halfbits = size_of::<Self>() * 4;
+        let mut tmp = self - one();
+        let mut shift = 1u;
+        while shift <= halfbits {
+            tmp = tmp | (tmp >> shift);
+            shift = shift << 1u;
+        }
+        tmp + one()
+    }
+
+    /// Returns the smallest power of two greater than or equal to `n`. If the
+    /// next power of two is greater than the type's maximum value, `None` is
+    /// returned, otherwise the power of two is wrapped in `Some`.
+    fn checked_next_power_of_two(self) -> Option<Self> {
+        let halfbits = size_of::<Self>() * 4;
+        let mut tmp = self - one();
+        let mut shift = 1u;
+        while shift <= halfbits {
+            tmp = tmp | (tmp >> shift);
+            shift = shift << 1u;
+        }
+        tmp.checked_add(&one())
     }
-    tmp + one()
 }
 
-// Returns `true` iff `n == 2^k` for some k.
-#[inline]
-pub fn is_power_of_two<T: Unsigned + Int>(n: T) -> bool {
-    (n - one()) & n == zero()
-}
-
-/// Returns the smallest power of 2 greater than or equal to `n`. If the next
-/// power of two is greater than the type's maximum value, `None` is returned,
-/// otherwise the power of 2 is wrapped in `Some`.
-#[inline]
-pub fn checked_next_power_of_two<T: Unsigned + Int>(n: T) -> Option<T> {
-    let halfbits = size_of::<T>() * 4;
-    let mut tmp: T = n - one();
-    let mut shift = 1u;
-    while shift <= halfbits {
-        tmp = tmp | (tmp >> shift);
-        shift = shift << 1u;
-    }
-    tmp.checked_add(&one())
-}
+impl UnsignedInt for uint {}
+impl UnsignedInt for u8 {}
+impl UnsignedInt for u16 {}
+impl UnsignedInt for u32 {}
+impl UnsignedInt for u64 {}
 
 /// A generic trait for converting a value to a number.
 pub trait ToPrimitive {
@@ -1525,4 +1532,18 @@ pub trait Float: Signed + Primitive {
 // DEPRECATED
 
 #[deprecated = "Use `Signed::abs`"]
-pub fn abs<T: Signed>(value: T) -> T { value.abs() }
+pub fn abs<T: Signed>(value: T) -> T {
+    value.abs()
+}
+#[deprecated = "Use `UnsignedInt::next_power_of_two`"]
+pub fn next_power_of_two<T: UnsignedInt>(n: T) -> T {
+    n.next_power_of_two()
+}
+#[deprecated = "Use `UnsignedInt::is_power_of_two`"]
+pub fn is_power_of_two<T: UnsignedInt>(n: T) -> bool {
+    n.is_power_of_two()
+}
+#[deprecated = "Use `UnsignedInt::checked_next_power_of_two`"]
+pub fn checked_next_power_of_two<T: UnsignedInt>(n: T) -> Option<T> {
+    n.checked_next_power_of_two()
+}

src/libstd/collections/hash/map.rs

@@ -18,7 +18,7 @@ use hash::{Hash, Hasher, RandomSipHasher};
 use iter::{mod, Iterator, FromIterator, Extend};
 use kinds::Sized;
 use mem::{mod, replace};
-use num;
+use num::UnsignedInt;
 use ops::{Deref, Index, IndexMut};
 use option::{Some, None, Option};
 use result::{Result, Ok, Err};
@@ -549,7 +549,7 @@ impl<K: Eq + Hash<S>, V, S, H: Hasher<S>> HashMap<K, V, H> {
     /// ```
     #[inline]
     pub fn with_capacity_and_hasher(capacity: uint, hasher: H) -> HashMap<K, V, H> {
-        let cap = num::next_power_of_two(max(INITIAL_CAPACITY, capacity));
+        let cap = max(INITIAL_CAPACITY, capacity).next_power_of_two();
         HashMap {
             hasher:        hasher,
             resize_policy: DefaultResizePolicy::new(cap),
@@ -572,8 +572,7 @@ impl<K: Eq + Hash<S>, V, S, H: Hasher<S>> HashMap<K, V, H> {
     /// map.reserve(10);
     /// ```
     pub fn reserve(&mut self, new_minimum_capacity: uint) {
-        let cap = num::next_power_of_two(
-            max(INITIAL_CAPACITY, new_minimum_capacity));
+        let cap = max(INITIAL_CAPACITY, new_minimum_capacity).next_power_of_two();
 
         self.resize_policy.reserve(cap);
 
@@ -588,7 +587,7 @@ impl<K: Eq + Hash<S>, V, S, H: Hasher<S>> HashMap<K, V, H> {
     ///   2) Ensure new_capacity is a power of two.
     fn resize(&mut self, new_capacity: uint) {
         assert!(self.table.size() <= new_capacity);
-        assert!(num::is_power_of_two(new_capacity));
+        assert!(new_capacity.is_power_of_two());
 
         let mut old_table = replace(&mut self.table, RawTable::new(new_capacity));
         let old_size = old_table.size();

src/libstd/collections/hash/table.rs

@@ -17,7 +17,7 @@ use iter::{Iterator, count};
 use kinds::{Sized, marker};
 use mem::{min_align_of, size_of};
 use mem;
-use num::{CheckedAdd, CheckedMul, is_power_of_two};
+use num::{CheckedAdd, CheckedMul, UnsignedInt};
 use ops::{Deref, DerefMut, Drop};
 use option::{Some, None, Option};
 use ptr::{RawPtr, copy_nonoverlapping_memory, zero_memory};
@@ -516,7 +516,7 @@ impl<K, V, M: Deref<RawTable<K, V>>> GapThenFull<K, V, M> {
 ///
 /// Fails if `target_alignment` is not a power of two.
 fn round_up_to_next(unrounded: uint, target_alignment: uint) -> uint {
-    assert!(is_power_of_two(target_alignment));
+    assert!(target_alignment.is_power_of_two());
     (unrounded + target_alignment - 1) & !(target_alignment - 1)
 }
 

src/libstd/num/mod.rs

@@ -23,7 +23,7 @@ use option::Option;
 pub use core::num::{Num, div_rem, Zero, zero, One, one};
 pub use core::num::{Signed, abs, signum};
 pub use core::num::{Unsigned, pow, Bounded};
-pub use core::num::{Primitive, Int, Saturating};
+pub use core::num::{Primitive, Int, UnsignedInt, Saturating};
 pub use core::num::{CheckedAdd, CheckedSub, CheckedMul, CheckedDiv};
 pub use core::num::{cast, FromPrimitive, NumCast, ToPrimitive};
 pub use core::num::{next_power_of_two, is_power_of_two};
@@ -672,10 +672,10 @@ mod tests {
         ($test_name:ident, $T:ident) => (
             fn $test_name() {
                 #![test]
-                assert_eq!(next_power_of_two::<$T>(0), 0);
+                assert_eq!((0 as $T).next_power_of_two(), 0);
                 let mut next_power = 1;
                 for i in range::<$T>(1, 40) {
-                     assert_eq!(next_power_of_two(i), next_power);
+                     assert_eq!(i.next_power_of_two(), next_power);
                      if i == next_power { next_power *= 2 }
                 }
             }
@@ -692,15 +692,15 @@ mod tests {
         ($test_name:ident, $T:ident) => (
             fn $test_name() {
                 #![test]
-                assert_eq!(checked_next_power_of_two::<$T>(0), None);
+                assert_eq!((0 as $T).checked_next_power_of_two(), None);
                 let mut next_power = 1;
                 for i in range::<$T>(1, 40) {
-                     assert_eq!(checked_next_power_of_two(i), Some(next_power));
+                     assert_eq!(i.checked_next_power_of_two(), Some(next_power));
                      if i == next_power { next_power *= 2 }
                 }
-                assert!(checked_next_power_of_two::<$T>($T::MAX / 2).is_some());
-                assert_eq!(checked_next_power_of_two::<$T>($T::MAX - 1), None);
-                assert_eq!(checked_next_power_of_two::<$T>($T::MAX), None);
+                assert!(($T::MAX / 2).checked_next_power_of_two().is_some());
+                assert_eq!(($T::MAX - 1).checked_next_power_of_two(), None);
+                assert_eq!($T::MAX.checked_next_power_of_two(), None);
             }
         )
     )

src/libsync/mpmc_bounded_queue.rs

@@ -34,7 +34,7 @@ use core::prelude::*;
 
 use alloc::arc::Arc;
 use collections::Vec;
-use core::num::next_power_of_two;
+use core::num::UnsignedInt;
 use core::cell::UnsafeCell;
 
 use atomic::{AtomicUint,Relaxed,Release,Acquire};
@@ -66,7 +66,7 @@ impl<T: Send> State<T> {
                 2u
             } else {
                 // use next power of 2 as capacity
-                next_power_of_two(capacity)
+                capacity.next_power_of_two()
             }
         } else {
             capacity