auto merge of #12382 : bjz/rust/fmt-int, r=alexcrichton

This is PR is the beginning of a complete rewrite and ultimate removal of the `std::num::strconv` module (see #6220), and the removal of the `ToStrRadix` trait in favour of using the `std::fmt` functionality directly. This should make for a cleaner API, encourage less allocation, and make the implementation more comprehensible .

The `Formatter::{pad_integral, with_padding}` methods have also been refactored make things easier to understand.

The formatting tests for integers have been moved out of `run-pass/ifmt.rs` in order to provide more immediate feedback when building using `make check-stage2-std NO_REBUILD=1`.

Arbitrary radixes are now easier to use in format strings. For example:

~~~rust
assert_eq!(format!("{:04}", radix(3, 2)), ~"0011");
~~~

The benchmarks have been standardised between `std::num::strconv` and `std::num::fmt` to make it easier to compare the performance of the different implementations.

~~~
 type | radix | std::num::strconv      | std::num::fmt
======|=======|========================|======================
 int  | bin   | 1748 ns/iter (+/- 150) | 321 ns/iter (+/- 25)
 int  | oct   |  706 ns/iter (+/- 53)  | 179 ns/iter (+/- 22)
 int  | dec   |  640 ns/iter (+/- 59)  | 207 ns/iter (+/- 10)
 int  | hex   |  637 ns/iter (+/- 77)  | 205 ns/iter (+/- 19)
 int  | 36    |  446 ns/iter (+/- 30)  | 309 ns/iter (+/- 20)
------|-------|------------------------|----------------------
 uint | bin   | 1724 ns/iter (+/- 159) | 322 ns/iter (+/- 13)
 uint | oct   |  663 ns/iter (+/- 25)  | 175 ns/iter (+/- 7)
 uint | dec   |  613 ns/iter (+/- 30)  | 186 ns/iter (+/- 6)
 uint | hex   |  519 ns/iter (+/- 44)  | 207 ns/iter (+/- 20)
 uint | 36    |  418 ns/iter (+/- 16)  | 308 ns/iter (+/- 32)
~~~

4 files changed, 93 insertions, 21 deletions

diff --git a/src/libstd/num/int_macros.rs b/src/libstd/num/int_macros.rs
index 7f45b5deb18..43a70190812 100644
--- a/src/libstd/num/int_macros.rs
+++ b/src/libstd/num/int_macros.rs
@@ -277,7 +277,7 @@ impl ToStr for $T {
     /// Convert to a string in base 10.
     #[inline]
     fn to_str(&self) -> ~str {
-        self.to_str_radix(10)
+        format!("{:d}", *self)
     }
 }
 
diff --git a/src/libstd/num/mod.rs b/src/libstd/num/mod.rs
index 332eb62b0c6..b23e42ad1c6 100644
--- a/src/libstd/num/mod.rs
+++ b/src/libstd/num/mod.rs
@@ -17,10 +17,12 @@
 
 use clone::{Clone, DeepClone};
 use cmp::{Eq, Ord};
+use kinds::Pod;
 use mem::size_of;
 use ops::{Add, Sub, Mul, Div, Rem, Neg};
 use ops::{Not, BitAnd, BitOr, BitXor, Shl, Shr};
 use option::{Option, Some, None};
+use fmt::{Show, Binary, Octal, LowerHex, UpperHex};
 
 pub mod strconv;
 
@@ -243,7 +245,8 @@ pub trait Bitwise: Bounded
 /// Specifies the available operations common to all of Rust's core numeric primitives.
 /// These may not always make sense from a purely mathematical point of view, but
 /// may be useful for systems programming.
-pub trait Primitive: Clone
+pub trait Primitive: Pod
+                   + Clone
                    + DeepClone
                    + Num
                    + NumCast
@@ -256,7 +259,12 @@ pub trait Int: Primitive
              + CheckedAdd
              + CheckedSub
              + CheckedMul
-             + CheckedDiv {}
+             + CheckedDiv
+             + Show
+             + Binary
+             + Octal
+             + LowerHex
+             + UpperHex {}
 
 /// Returns the smallest power of 2 greater than or equal to `n`.
 #[inline]
diff --git a/src/libstd/num/strconv.rs b/src/libstd/num/strconv.rs
index bc79ec9a4af..153c042c6a8 100644
--- a/src/libstd/num/strconv.rs
+++ b/src/libstd/num/strconv.rs
@@ -792,24 +792,88 @@ mod test {
 #[cfg(test)]
 mod bench {
     extern crate test;
-    use self::test::BenchHarness;
-    use rand::{XorShiftRng, Rng};
-    use to_str::ToStr;
-    use f64;
-
-    #[bench]
-    fn uint_to_str_rand(bh: &mut BenchHarness) {
-        let mut rng = XorShiftRng::new();
-        bh.iter(|| {
-            rng.gen::<uint>().to_str();
-        })
+
+    mod uint {
+        use super::test::BenchHarness;
+        use rand::{XorShiftRng, Rng};
+        use num::ToStrRadix;
+
+        #[bench]
+        fn to_str_bin(bh: &mut BenchHarness) {
+            let mut rng = XorShiftRng::new();
+            bh.iter(|| { rng.gen::<uint>().to_str_radix(2); })
+        }
+
+        #[bench]
+        fn to_str_oct(bh: &mut BenchHarness) {
+            let mut rng = XorShiftRng::new();
+            bh.iter(|| { rng.gen::<uint>().to_str_radix(8); })
+        }
+
+        #[bench]
+        fn to_str_dec(bh: &mut BenchHarness) {
+            let mut rng = XorShiftRng::new();
+            bh.iter(|| { rng.gen::<uint>().to_str_radix(10); })
+        }
+
+        #[bench]
+        fn to_str_hex(bh: &mut BenchHarness) {
+            let mut rng = XorShiftRng::new();
+            bh.iter(|| { rng.gen::<uint>().to_str_radix(16); })
+        }
+
+        #[bench]
+        fn to_str_base_36(bh: &mut BenchHarness) {
+            let mut rng = XorShiftRng::new();
+            bh.iter(|| { rng.gen::<uint>().to_str_radix(36); })
+        }
     }
 
-    #[bench]
-    fn float_to_str_rand(bh: &mut BenchHarness) {
-        let mut rng = XorShiftRng::new();
-        bh.iter(|| {
-            f64::to_str(rng.gen());
-        })
+    mod int {
+        use super::test::BenchHarness;
+        use rand::{XorShiftRng, Rng};
+        use num::ToStrRadix;
+
+        #[bench]
+        fn to_str_bin(bh: &mut BenchHarness) {
+            let mut rng = XorShiftRng::new();
+            bh.iter(|| { rng.gen::<int>().to_str_radix(2); })
+        }
+
+        #[bench]
+        fn to_str_oct(bh: &mut BenchHarness) {
+            let mut rng = XorShiftRng::new();
+            bh.iter(|| { rng.gen::<int>().to_str_radix(8); })
+        }
+
+        #[bench]
+        fn to_str_dec(bh: &mut BenchHarness) {
+            let mut rng = XorShiftRng::new();
+            bh.iter(|| { rng.gen::<int>().to_str_radix(10); })
+        }
+
+        #[bench]
+        fn to_str_hex(bh: &mut BenchHarness) {
+            let mut rng = XorShiftRng::new();
+            bh.iter(|| { rng.gen::<int>().to_str_radix(16); })
+        }
+
+        #[bench]
+        fn to_str_base_36(bh: &mut BenchHarness) {
+            let mut rng = XorShiftRng::new();
+            bh.iter(|| { rng.gen::<int>().to_str_radix(36); })
+        }
+    }
+
+    mod f64 {
+        use super::test::BenchHarness;
+        use rand::{XorShiftRng, Rng};
+        use f64;
+
+        #[bench]
+        fn float_to_str(bh: &mut BenchHarness) {
+            let mut rng = XorShiftRng::new();
+            bh.iter(|| { f64::to_str(rng.gen()); })
+        }
     }
 }
diff --git a/src/libstd/num/uint_macros.rs b/src/libstd/num/uint_macros.rs
index 33fcdcc426a..d60b5235446 100644
--- a/src/libstd/num/uint_macros.rs
+++ b/src/libstd/num/uint_macros.rs
@@ -191,7 +191,7 @@ impl ToStr for $T {
     /// Convert to a string in base 10.
     #[inline]
     fn to_str(&self) -> ~str {
-        self.to_str_radix(10u)
+        format!("{:u}", *self)
     }
 }