rollup merge of #20518: nagisa/weighted-bool

[rust.git] / src / librand / lib.rs

diff --git a/src/librand/lib.rs b/src/librand/lib.rs
index 514ff81da518ec789c5614c169b197aa7a9887b0..f538e0ade05f5f5e1d32fe442c82a2389dbf7ae9 100644 (file)
--- a/src/librand/lib.rs
+++ b/src/librand/lib.rs
@@ -25,6 +25,7 @@
 
 #![feature(macro_rules, phase, globs)]
 #![feature(unboxed_closures)]
+#![feature(associated_types)]
 #![no_std]
 #![experimental]
 
@@ -52,14 +53,14 @@
 mod rand_impls;
 
 /// A type that can be randomly generated using an `Rng`.
-pub trait Rand {
+pub trait Rand : Sized {
     /// Generates a random instance of this type using the specified source of
     /// randomness.
     fn rand<R: Rng>(rng: &mut R) -> Self;
 }
 
 /// A random number generator.
-pub trait Rng {
+pub trait Rng : Sized {
     /// Return the next random u32.
     ///
     /// This rarely needs to be called directly, prefer `r.gen()` to
@@ -74,7 +75,7 @@ pub trait Rng {
     /// these two methods. Similarly to `next_u32`, this rarely needs
     /// to be called directly, prefer `r.gen()` to `r.next_u64()`.
     fn next_u64(&mut self) -> u64 {
-        (self.next_u32() as u64 << 32) | (self.next_u32() as u64)
+        ((self.next_u32() as u64) << 32) | (self.next_u32() as u64)
     }
 
     /// Return the next random f32 selected from the half-open
@@ -138,10 +139,10 @@ fn next_f64(&mut self) -> f64 {
     /// # Example
     ///
     /// ```rust
-    /// use std::rand::{task_rng, Rng};
+    /// use std::rand::{thread_rng, Rng};
     ///
-    /// let mut v = [0u8, .. 13579];
-    /// task_rng().fill_bytes(&mut v);
+    /// let mut v = [0u8; 13579];
+    /// thread_rng().fill_bytes(&mut v);
     /// println!("{}", v.as_slice());
     /// ```
     fn fill_bytes(&mut self, dest: &mut [u8]) {
@@ -173,9 +174,9 @@ fn fill_bytes(&mut self, dest: &mut [u8]) {
     /// # Example
     ///
     /// ```rust
-    /// use std::rand::{task_rng, Rng};
+    /// use std::rand::{thread_rng, Rng};
     ///
-    /// let mut rng = task_rng();
+    /// let mut rng = thread_rng();
     /// let x: uint = rng.gen();
     /// println!("{}", x);
     /// println!("{}", rng.gen::<(f64, bool)>());
@@ -191,9 +192,9 @@ fn gen<T: Rand>(&mut self) -> T {
     /// # Example
     ///
     /// ```
-    /// use std::rand::{task_rng, Rng};
+    /// use std::rand::{thread_rng, Rng};
     ///
-    /// let mut rng = task_rng();
+    /// let mut rng = thread_rng();
     /// let x = rng.gen_iter::<uint>().take(10).collect::<Vec<uint>>();
     /// println!("{}", x);
     /// println!("{}", rng.gen_iter::<(f64, bool)>().take(5)
@@ -218,9 +219,9 @@ fn gen_iter<'a, T: Rand>(&'a mut self) -> Generator<'a, T, Self> {
     /// # Example
     ///
     /// ```rust
-    /// use std::rand::{task_rng, Rng};
+    /// use std::rand::{thread_rng, Rng};
     ///
-    /// let mut rng = task_rng();
+    /// let mut rng = thread_rng();
     /// let n: uint = rng.gen_range(0u, 10);
     /// println!("{}", n);
     /// let m: f64 = rng.gen_range(-40.0f64, 1.3e5f64);
@@ -236,13 +237,13 @@ fn gen_range<T: PartialOrd + SampleRange>(&mut self, low: T, high: T) -> T {
     /// # Example
     ///
     /// ```rust
-    /// use std::rand::{task_rng, Rng};
+    /// use std::rand::{thread_rng, Rng};
     ///
-    /// let mut rng = task_rng();
+    /// let mut rng = thread_rng();
     /// println!("{}", rng.gen_weighted_bool(3));
     /// ```
     fn gen_weighted_bool(&mut self, n: uint) -> bool {
-        n == 0 || self.gen_range(0, n) == 0
+        n <= 1 || self.gen_range(0, n) == 0
     }
 
     /// Return an iterator of random characters from the set A-Z,a-z,0-9.
@@ -250,9 +251,9 @@ fn gen_weighted_bool(&mut self, n: uint) -> bool {
     /// # Example
     ///
     /// ```rust
-    /// use std::rand::{task_rng, Rng};
+    /// use std::rand::{thread_rng, Rng};
     ///
-    /// let s: String = task_rng().gen_ascii_chars().take(10).collect();
+    /// let s: String = thread_rng().gen_ascii_chars().take(10).collect();
     /// println!("{}", s);
     /// ```
     fn gen_ascii_chars<'a>(&'a mut self) -> AsciiGenerator<'a, Self> {
@@ -266,12 +267,13 @@ fn gen_ascii_chars<'a>(&'a mut self) -> AsciiGenerator<'a, Self> {
     /// # Example
     ///
     /// ```
-    /// use std::rand::{task_rng, Rng};
+    /// use std::rand::{thread_rng, Rng};
     ///
-    /// let choices = [1i, 2, 4, 8, 16, 32];
-    /// let mut rng = task_rng();
+    /// let choices = [1, 2, 4, 8, 16, 32];
+    /// let mut rng = thread_rng();
     /// println!("{}", rng.choose(&choices));
-    /// assert_eq!(rng.choose(choices[..0]), None);
+    /// # // replace with slicing syntax when it's stable!
+    /// assert_eq!(rng.choose(choices.slice_to(0)), None);
     /// ```
     fn choose<'a, T>(&mut self, values: &'a [T]) -> Option<&'a T> {
         if values.is_empty() {
@@ -286,10 +288,10 @@ fn choose<'a, T>(&mut self, values: &'a [T]) -> Option<&'a T> {
     /// # Example
     ///
     /// ```rust
-    /// use std::rand::{task_rng, Rng};
+    /// use std::rand::{thread_rng, Rng};
     ///
-    /// let mut rng = task_rng();
-    /// let mut y = [1i, 2, 3];
+    /// let mut rng = thread_rng();
+    /// let mut y = [1, 2, 3];
     /// rng.shuffle(&mut y);
     /// println!("{}", y.as_slice());
     /// rng.shuffle(&mut y);
@@ -313,7 +315,9 @@ pub struct Generator<'a, T, R:'a> {
     rng: &'a mut R,
 }
 
-impl<'a, T: Rand, R: Rng> Iterator<T> for Generator<'a, T, R> {
+impl<'a, T: Rand, R: Rng> Iterator for Generator<'a, T, R> {
+    type Item = T;
+
     fn next(&mut self) -> Option<T> {
         Some(self.rng.gen())
     }
@@ -326,7 +330,9 @@ pub struct AsciiGenerator<'a, R:'a> {
     rng: &'a mut R,
 }
 
-impl<'a, R: Rng> Iterator<char> for AsciiGenerator<'a, R> {
+impl<'a, R: Rng> Iterator for AsciiGenerator<'a, R> {
+    type Item = char;
+
     fn next(&mut self) -> Option<char> {
         static GEN_ASCII_STR_CHARSET: &'static [u8] =
             b"ABCDEFGHIJKLMNOPQRSTUVWXYZ\
@@ -379,6 +385,7 @@ pub trait SeedableRng<Seed>: Rng {
 /// RNGs"](http://www.jstatsoft.org/v08/i14/paper). *Journal of
 /// Statistical Software*. Vol. 8 (Issue 14).
 #[allow(missing_copy_implementations)]
+#[deriving(Clone)]
 pub struct XorShiftRng {
     x: u32,
     y: u32,
@@ -386,17 +393,6 @@ pub struct XorShiftRng {
     w: u32,
 }
 
-impl Clone for XorShiftRng {
-    fn clone(&self) -> XorShiftRng {
-        XorShiftRng {
-            x: self.x,
-            y: self.y,
-            z: self.z,
-            w: self.w,
-        }
-    }
-}
-
 impl XorShiftRng {
     /// Creates a new XorShiftRng instance which is not seeded.
     ///
@@ -428,9 +424,9 @@ fn next_u32(&mut self) -> u32 {
     }
 }
 
-impl SeedableRng<[u32, .. 4]> for XorShiftRng {
+impl SeedableRng<[u32; 4]> for XorShiftRng {
     /// Reseed an XorShiftRng. This will panic if `seed` is entirely 0.
-    fn reseed(&mut self, seed: [u32, .. 4]) {
+    fn reseed(&mut self, seed: [u32; 4]) {
         assert!(!seed.iter().all(|&x| x == 0),
                 "XorShiftRng.reseed called with an all zero seed.");
 
@@ -441,7 +437,7 @@ fn reseed(&mut self, seed: [u32, .. 4]) {
     }
 
     /// Create a new XorShiftRng. This will panic if `seed` is entirely 0.
-    fn from_seed(seed: [u32, .. 4]) -> XorShiftRng {
+    fn from_seed(seed: [u32; 4]) -> XorShiftRng {
         assert!(!seed.iter().all(|&x| x == 0),
                 "XorShiftRng::from_seed called with an all zero seed.");
 
@@ -501,6 +497,7 @@ fn rand<R: Rng>(rng: &mut R) -> XorShiftRng {
 #[cfg(not(test))]
 mod std {
     pub use core::{option, fmt}; // panic!()
+    pub use core::clone; // derive Clone
     pub use core::kinds;
 }
 
@@ -520,8 +517,8 @@ fn next<T: rand::Rng>(t: &mut T) -> u32 {
         }
     }
 
-    pub fn rng() -> MyRng<rand::TaskRng> {
-        MyRng { inner: rand::task_rng() }
+    pub fn rng() -> MyRng<rand::ThreadRng> {
+        MyRng { inner: rand::thread_rng() }
     }
 
     pub fn weak_rng() -> MyRng<rand::XorShiftRng> {