std::rand: move the Rand impls into a separate file for neatness.

1 files changed, 199 insertions, 0 deletions

diff --git a/src/libstd/rand/rand_impls.rs b/src/libstd/rand/rand_impls.rs
new file mode 100644
index 00000000000..22980a3e1c4
--- /dev/null
+++ b/src/libstd/rand/rand_impls.rs
@@ -0,0 +1,199 @@
+// Copyright 2013 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.
+
+//! The implementations of `Rand` for the built-in types.
+
+use char;
+use int;
+use option::{Option, Some, None};
+use rand::{Rand,Rng};
+use u32;
+use uint;
+
+impl Rand for int {
+    #[inline]
+    fn rand<R: Rng>(rng: &mut R) -> int {
+        if int::bits == 32 {
+            rng.gen::<i32>() as int
+        } else {
+            rng.gen::<i64>() as int
+        }
+    }
+}
+
+impl Rand for i8 {
+    #[inline]
+    fn rand<R: Rng>(rng: &mut R) -> i8 {
+        rng.next_u32() as i8
+    }
+}
+
+impl Rand for i16 {
+    #[inline]
+    fn rand<R: Rng>(rng: &mut R) -> i16 {
+        rng.next_u32() as i16
+    }
+}
+
+impl Rand for i32 {
+    #[inline]
+    fn rand<R: Rng>(rng: &mut R) -> i32 {
+        rng.next_u32() as i32
+    }
+}
+
+impl Rand for i64 {
+    #[inline]
+    fn rand<R: Rng>(rng: &mut R) -> i64 {
+        rng.next_u64() as i64
+    }
+}
+
+impl Rand for uint {
+    #[inline]
+    fn rand<R: Rng>(rng: &mut R) -> uint {
+        if uint::bits == 32 {
+            rng.gen::<u32>() as uint
+        } else {
+            rng.gen::<u64>() as uint
+        }
+    }
+}
+
+impl Rand for u8 {
+    #[inline]
+    fn rand<R: Rng>(rng: &mut R) -> u8 {
+        rng.next_u32() as u8
+    }
+}
+
+impl Rand for u16 {
+    #[inline]
+    fn rand<R: Rng>(rng: &mut R) -> u16 {
+        rng.next_u32() as u16
+    }
+}
+
+impl Rand for u32 {
+    #[inline]
+    fn rand<R: Rng>(rng: &mut R) -> u32 {
+        rng.next_u32()
+    }
+}
+
+impl Rand for u64 {
+    #[inline]
+    fn rand<R: Rng>(rng: &mut R) -> u64 {
+        rng.next_u64()
+    }
+}
+
+impl Rand for f32 {
+    #[inline]
+    fn rand<R: Rng>(rng: &mut R) -> f32 {
+        rng.gen::<f64>() as f32
+    }
+}
+
+static SCALE : f64 = (u32::max_value as f64) + 1.0f64;
+impl Rand for f64 {
+    #[inline]
+    fn rand<R: Rng>(rng: &mut R) -> f64 {
+        let u1 = rng.next_u32() as f64;
+        let u2 = rng.next_u32() as f64;
+        let u3 = rng.next_u32() as f64;
+
+        ((u1 / SCALE + u2) / SCALE + u3) / SCALE
+    }
+}
+
+
+impl Rand for char {
+    #[inline]
+    fn rand<R: Rng>(rng: &mut R) -> char {
+        // a char is 21 bits
+        static CHAR_MASK: u32 = 0x001f_ffff;
+        loop {
+            // Rejection sampling. About 0.2% of numbers with at most
+            // 21-bits are invalid codepoints (surrogates), so this
+            // will succeed first go almost every time.
+            match char::from_u32(rng.next_u32() & CHAR_MASK) {
+                Some(c) => return c,
+                None => {}
+            }
+        }
+    }
+}
+
+impl Rand for bool {
+    #[inline]
+    fn rand<R: Rng>(rng: &mut R) -> bool {
+        rng.gen::<u8>() & 1 == 1
+    }
+}
+
+macro_rules! tuple_impl {
+    // use variables to indicate the arity of the tuple
+    ($($tyvar:ident),* ) => {
+        // the trailing commas are for the 1 tuple
+        impl<
+            $( $tyvar : Rand ),*
+            > Rand for ( $( $tyvar ),* , ) {
+
+            #[inline]
+            fn rand<R: Rng>(_rng: &mut R) -> ( $( $tyvar ),* , ) {
+                (
+                    // use the $tyvar's to get the appropriate number of
+                    // repeats (they're not actually needed)
+                    $(
+                        _rng.gen::<$tyvar>()
+                    ),*
+                    ,
+                )
+            }
+        }
+    }
+}
+
+impl Rand for () {
+    #[inline]
+    fn rand<R: Rng>(_: &mut R) -> () { () }
+}
+tuple_impl!{A}
+tuple_impl!{A, B}
+tuple_impl!{A, B, C}
+tuple_impl!{A, B, C, D}
+tuple_impl!{A, B, C, D, E}
+tuple_impl!{A, B, C, D, E, F}
+tuple_impl!{A, B, C, D, E, F, G}
+tuple_impl!{A, B, C, D, E, F, G, H}
+tuple_impl!{A, B, C, D, E, F, G, H, I}
+tuple_impl!{A, B, C, D, E, F, G, H, I, J}
+
+impl<T:Rand> Rand for Option<T> {
+    #[inline]
+    fn rand<R: Rng>(rng: &mut R) -> Option<T> {
+        if rng.gen() {
+            Some(rng.gen())
+        } else {
+            None
+        }
+    }
+}
+
+impl<T: Rand> Rand for ~T {
+    #[inline]
+    fn rand<R: Rng>(rng: &mut R) -> ~T { ~rng.gen() }
+}
+
+impl<T: Rand + 'static> Rand for @T {
+    #[inline]
+    fn rand<R: Rng>(rng: &mut R) -> @T { @rng.gen() }
+}