// Copyright 2018 Developers of the Rand project.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
//
https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or
https://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
//! The implementations of the `Standard` distribution for integer types.
use crate::distributions::{Distribution, Standard};
use crate::Rng;
#[cfg(all(target_arch = "x86", feature = "simd_support"))]
use core::arch::x86::{__m128i, __m256i};
#[cfg(all(target_arch = "x86_64", feature = "simd_support"))]
use core::arch::x86_64::{__m128i, __m256i};
use core::num::{NonZeroU16, NonZeroU32, NonZeroU64, NonZeroU8, NonZeroUsize,
NonZeroU128};
#[cfg(feature = "simd_support")] use packed_simd::*;
impl Distribution<u8> for Standard {
#[inline]
fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> u8 {
rng.next_u32() as u8
}
}
impl Distribution<u16> for Standard {
#[inline]
fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> u16 {
rng.next_u32() as u16
}
}
impl Distribution<u32> for Standard {
#[inline]
fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> u32 {
rng.next_u32()
}
}
impl Distribution<u64> for Standard {
#[inline]
fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> u64 {
rng.next_u64()
}
}
impl Distribution<u128> for Standard {
#[inline]
fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> u128 {
// Use LE; we explicitly generate one value before the next.
let x = u128::from(rng.next_u64());
let y = u128::from(rng.next_u64());
(y << 64) | x
}
}
impl Distribution<usize> for Standard {
#[inline]
#[cfg(any(target_pointer_width = "32", target_pointer_width = "16"))]
fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> usize {
rng.next_u32() as usize
}
#[inline]
#[cfg(target_pointer_width = "64")]
fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> usize {
rng.next_u64() as usize
}
}
macro_rules! impl_int_from_uint {
($ty:ty, $uty:ty) => {
impl Distribution<$ty> for Standard {
#[inline]
fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> $ty {
rng.gen::<$uty>() as $ty
}
}
};
}
impl_int_from_uint! { i8, u8 }
impl_int_from_uint! { i16, u16 }
impl_int_from_uint! { i32, u32 }
impl_int_from_uint! { i64, u64 }
impl_int_from_uint! { i128, u128 }
impl_int_from_uint! { isize, usize }
macro_rules! impl_nzint {
($ty:ty, $new:path) => {
impl Distribution<$ty> for Standard {
fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> $ty {
loop {
if let Some(nz) = $new(rng.gen()) {
break nz;
}
}
}
}
};
}
impl_nzint!(NonZeroU8, NonZeroU8::new);
impl_nzint!(NonZeroU16, NonZeroU16::new);
impl_nzint!(NonZeroU32, NonZeroU32::new);
impl_nzint!(NonZeroU64, NonZeroU64::new);
impl_nzint!(NonZeroU128, NonZeroU128::new);
impl_nzint!(NonZeroUsize, NonZeroUsize::new);
#[cfg(feature = "simd_support")]
macro_rules! simd_impl {
($(($intrinsic:ident, $vec:ty),)+) => {$(
impl Distribution<$intrinsic> for Standard {
#[inline]
fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> $intrinsic {
$intrinsic::from_bits(rng.gen::<$vec>())
}
}
)+};
($bits:expr,) => {};
($bits:expr, $ty:ty, $($ty_more:ty,)*) => {
simd_impl!($bits, $($ty_more,)*);
impl Distribution<$ty> for Standard {
#[inline]
fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> $ty {
let mut vec: $ty = Default::default();
unsafe {
let ptr = &mut vec;
let b_ptr = &mut *(ptr as *mut $ty as *mut [u8; $bits/8]);
rng.fill_bytes(b_ptr);
}
vec.to_le()
}
}
};
}
#[cfg(feature = "simd_support")]
simd_impl!(16, u8x2, i8x2,);
#[cfg(feature = "simd_support")]
simd_impl!(32, u8x4, i8x4, u16x2, i16x2,);
#[cfg(feature = "simd_support")]
simd_impl!(64, u8x8, i8x8, u16x4, i16x4, u32x2, i32x2,);
#[cfg(feature = "simd_support")]
simd_impl!(128, u8x16, i8x16, u16x8, i16x8, u32x4, i32x4, u64x2, i64x2,);
#[cfg(feature = "simd_support")]
simd_impl!(256, u8x32, i8x32, u16x16, i16x16, u32x8, i32x8, u64x4, i64x4,);
#[cfg(feature = "simd_support")]
simd_impl!(512, u8x64, i8x64, u16x32, i16x32, u32x16, i32x16, u64x8, i64x8,);
#[cfg(all(
feature = "simd_support",
any(target_arch = "x86", target_arch = "x86_64")
))]
simd_impl!((__m128i, u8x16), (__m256i, u8x32),);
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_integers() {
let mut rng = crate::test::rng(806);
rng.sample::<isize, _>(Standard);
rng.sample::<i8, _>(Standard);
rng.sample::<i16, _>(Standard);
rng.sample::<i32, _>(Standard);
rng.sample::<i64, _>(Standard);
rng.sample::<i128, _>(Standard);
rng.sample::<usize, _>(Standard);
rng.sample::<u8, _>(Standard);
rng.sample::<u16, _>(Standard);
rng.sample::<u32, _>(Standard);
rng.sample::<u64, _>(Standard);
rng.sample::<u128, _>(Standard);
}
#[test]
fn value_stability() {
fn test_samples<T: Copy + core::fmt::Debug + PartialEq>(zero: T, expected: &[T])
where Standard: Distribution<T> {
let mut rng = crate::test::rng(807);
let mut buf = [zero; 3];
for x in &mut buf {
*x = rng.sample(Standard);
}
assert_eq!(&buf, expected);
}
test_samples(0u8, &[9, 247, 111]);
test_samples(0u16, &[32265, 42999, 38255]);
test_samples(0u32, &[2220326409, 2575017975, 2018088303]);
test_samples(0u64, &[
11059617991457472009,
16096616328739788143,
1487364411147516184,
]);
test_samples(0u128, &[
296930161868957086625409848350820761097,
145644820879247630242265036535529306392,
111087889832015897993126088499035356354,
]);
#[cfg(any(target_pointer_width = "32", target_pointer_width = "16"))]
test_samples(0usize, &[2220326409, 2575017975, 2018088303]);
#[cfg(target_pointer_width = "64")]
test_samples(0usize, &[
11059617991457472009,
16096616328739788143,
1487364411147516184,
]);
test_samples(0i8, &[9, -9, 111]);
// Skip further i* types: they are simple reinterpretation of u* samples
#[cfg(feature = "simd_support")]
{
// We only test a sub-set of types here and make assumptions about the rest.
test_samples(u8x2::default(), &[
u8x2::new(9, 126),
u8x2::new(247, 167),
u8x2::new(111, 149),
]);
test_samples(u8x4::default(), &[
u8x4::new(9, 126, 87, 132),
u8x4::new(247, 167, 123, 153),
u8x4::new(111, 149, 73, 120),
]);
test_samples(u8x8::default(), &[
u8x8::new(9, 126, 87, 132, 247, 167, 123, 153),
u8x8::new(111, 149, 73, 120, 68, 171, 98, 223),
u8x8::new(24, 121, 1, 50, 13, 46, 164, 20),
]);
test_samples(i64x8::default(), &[
i64x8::new(
-7387126082252079607,
-2350127744969763473,
1487364411147516184,
7895421560427121838,
602190064936008898,
6022086574635100741,
-5080089175222015595,
-4066367846667249123,
),
i64x8::new(
9180885022207963908,
3095981199532211089,
6586075293021332726,
419343203796414657,
3186951873057035255,
5287129228749947252,
444726432079249540,
-1587028029513790706,
),
i64x8::new(
6075236523189346388,
1351763722368165432,
-6192309979959753740,
-7697775502176768592,
-4482022114172078123,
7522501477800909500,
-1837258847956201231,
-586926753024886735,
),
]);
}
}
}
