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// 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 {Rng};
use distributions::{Distribution, Standard};
#[cfg(feature="simd_support")]
use packed_simd::*;
#[cfg(all(target_arch = "x86", feature="nightly"))]
use core::arch::x86::*;
#[cfg(all(target_arch = "x86_64", feature="nightly"))]
use core::arch::x86_64::*;
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()
}
}
#[cfg(all(rustc_1_26, not(target_os = "emscripten")))]
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 = rng.next_u64() as u128;
let y = rng.next_u64() as u128;
(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 $ty
}
}
}
}
impl_int_from_uint! { i8, u8 }
impl_int_from_uint! { i16, u16 }
impl_int_from_uint! { i32, u32 }
impl_int_from_uint! { i64, u64 }
#[cfg(all(rustc_1_26, not(target_os = "emscripten")))] impl_int_from_uint! { i128, u128 }
impl_int_from_uint! { isize, usize }
#[cfg(feature="simd_support")]
macro_rules! simd_impl {
($(($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", feature="nightly", any(target_arch="x86", target_arch="x86_64")))]
simd_impl!((__m64, u8x8), (__m128i, u8x16), (__m256i, u8x32),);
#[cfg(test)]
mod tests {
use Rng;
use distributions::{Standard};
#[test]
fn test_integers() {
let mut rng = ::test::rng(806);
rng.sample::<isize, _>(Standard);
rng.sample::<i8, _>(Standard);
rng.sample::<i16, _>(Standard);
rng.sample::<i32, _>(Standard);
rng.sample::<i64, _>(Standard);
#[cfg(all(rustc_1_26, not(target_os = "emscripten")))]
rng.sample::<i128, _>(Standard);
rng.sample::<usize, _>(Standard);
rng.sample::<u8, _>(Standard);
rng.sample::<u16, _>(Standard);
rng.sample::<u32, _>(Standard);
rng.sample::<u64, _>(Standard);
#[cfg(all(rustc_1_26, not(target_os = "emscripten")))]
rng.sample::<u128, _>(Standard);
}
}
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