Vendor dependencies

Let's see how I like this workflow.

vendor/rand/src/rand_impls.rs

@@ -0,0 +1,299 @@
+// Copyright 2013-2014 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 core::{char, mem};
+
+use {Rand,Rng};
+
+impl Rand for isize {
+    #[inline]
+    fn rand<R: Rng>(rng: &mut R) -> isize {
+        if mem::size_of::<isize>() == 4 {
+            rng.gen::<i32>() as isize
+        } else {
+            rng.gen::<i64>() as isize
+        }
+    }
+}
+
+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
+    }
+}
+
+#[cfg(feature = "i128_support")]
+impl Rand for i128 {
+    #[inline]
+    fn rand<R: Rng>(rng: &mut R) -> i128 {
+        rng.gen::<u128>() as i128
+    }
+}
+
+impl Rand for usize {
+    #[inline]
+    fn rand<R: Rng>(rng: &mut R) -> usize {
+        if mem::size_of::<usize>() == 4 {
+            rng.gen::<u32>() as usize
+        } else {
+            rng.gen::<u64>() as usize
+        }
+    }
+}
+
+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()
+    }
+}
+
+#[cfg(feature = "i128_support")]
+impl Rand for u128 {
+    #[inline]
+    fn rand<R: Rng>(rng: &mut R) -> u128 {
+        ((rng.next_u64() as u128) << 64) | (rng.next_u64() as u128)
+    }
+}
+
+
+macro_rules! float_impls {
+    ($mod_name:ident, $ty:ty, $mantissa_bits:expr, $method_name:ident) => {
+        mod $mod_name {
+            use {Rand, Rng, Open01, Closed01};
+
+            const SCALE: $ty = (1u64 << $mantissa_bits) as $ty;
+
+            impl Rand for $ty {
+                /// Generate a floating point number in the half-open
+                /// interval `[0,1)`.
+                ///
+                /// See `Closed01` for the closed interval `[0,1]`,
+                /// and `Open01` for the open interval `(0,1)`.
+                #[inline]
+                fn rand<R: Rng>(rng: &mut R) -> $ty {
+                    rng.$method_name()
+                }
+            }
+            impl Rand for Open01<$ty> {
+                #[inline]
+                fn rand<R: Rng>(rng: &mut R) -> Open01<$ty> {
+                    // add a small amount (specifically 2 bits below
+                    // the precision of f64/f32 at 1.0), so that small
+                    // numbers are larger than 0, but large numbers
+                    // aren't pushed to/above 1.
+                    Open01(rng.$method_name() + 0.25 / SCALE)
+                }
+            }
+            impl Rand for Closed01<$ty> {
+                #[inline]
+                fn rand<R: Rng>(rng: &mut R) -> Closed01<$ty> {
+                    // rescale so that 1.0 - epsilon becomes 1.0
+                    // precisely.
+                    Closed01(rng.$method_name() * SCALE / (SCALE - 1.0))
+                }
+            }
+        }
+    }
+}
+float_impls! { f64_rand_impls, f64, 53, next_f64 }
+float_impls! { f32_rand_impls, f32, 24, next_f32 }
+
+impl Rand for char {
+    #[inline]
+    fn rand<R: Rng>(rng: &mut R) -> char {
+        // a char is 21 bits
+        const 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}
+tuple_impl!{A, B, C, D, E, F, G, H, I, J, K}
+tuple_impl!{A, B, C, D, E, F, G, H, I, J, K, L}
+
+macro_rules! array_impl {
+    {$n:expr, $t:ident, $($ts:ident,)*} => {
+        array_impl!{($n - 1), $($ts,)*}
+
+        impl<T> Rand for [T; $n] where T: Rand {
+            #[inline]
+            fn rand<R: Rng>(_rng: &mut R) -> [T; $n] {
+                [_rng.gen::<$t>(), $(_rng.gen::<$ts>()),*]
+            }
+        }
+    };
+    {$n:expr,} => {
+        impl<T> Rand for [T; $n] {
+            fn rand<R: Rng>(_rng: &mut R) -> [T; $n] { [] }
+        }
+    };
+}
+
+array_impl!{32, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T,}
+
+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
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use {Rng, thread_rng, Open01, Closed01};
+
+    struct ConstantRng(u64);
+    impl Rng for ConstantRng {
+        fn next_u32(&mut self) -> u32 {
+            let ConstantRng(v) = *self;
+            v as u32
+        }
+        fn next_u64(&mut self) -> u64 {
+            let ConstantRng(v) = *self;
+            v
+        }
+    }
+
+    #[test]
+    fn floating_point_edge_cases() {
+        // the test for exact equality is correct here.
+        assert!(ConstantRng(0xffff_ffff).gen::<f32>() != 1.0);
+        assert!(ConstantRng(0xffff_ffff_ffff_ffff).gen::<f64>() != 1.0);
+    }
+
+    #[test]
+    fn rand_open() {
+        // this is unlikely to catch an incorrect implementation that
+        // generates exactly 0 or 1, but it keeps it sane.
+        let mut rng = thread_rng();
+        for _ in 0..1_000 {
+            // strict inequalities
+            let Open01(f) = rng.gen::<Open01<f64>>();
+            assert!(0.0 < f && f < 1.0);
+
+            let Open01(f) = rng.gen::<Open01<f32>>();
+            assert!(0.0 < f && f < 1.0);
+        }
+    }
+
+    #[test]
+    fn rand_closed() {
+        let mut rng = thread_rng();
+        for _ in 0..1_000 {
+            // strict inequalities
+            let Closed01(f) = rng.gen::<Closed01<f64>>();
+            assert!(0.0 <= f && f <= 1.0);
+
+            let Closed01(f) = rng.gen::<Closed01<f32>>();
+            assert!(0.0 <= f && f <= 1.0);
+        }
+    }
+}