/rust/registry/src/index.crates.io-1949cf8c6b5b557f/rand-0.10.1/src/distr/integer.rs

Source
// 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 `StandardUniform` distribution for integer types.

use crate::distr::{Distribution, StandardUniform};
use crate::{Rng, RngExt};
#[cfg(all(target_arch = "x86", feature = "simd_support"))]
use core::arch::x86::__m512i;
#[cfg(target_arch = "x86")]
use core::arch::x86::{__m128i, __m256i};
#[cfg(all(target_arch = "x86_64", feature = "simd_support"))]
use core::arch::x86_64::__m512i;
#[cfg(target_arch = "x86_64")]
use core::arch::x86_64::{__m128i, __m256i};
use core::num::{
    NonZeroI8, NonZeroI16, NonZeroI32, NonZeroI64, NonZeroI128, NonZeroU8, NonZeroU16, NonZeroU32,
    NonZeroU64, NonZeroU128,
};
#[cfg(feature = "simd_support")]
use core::simd::*;

impl Distribution<u8> for StandardUniform {
    #[inline]
    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> u8 {
        rng.next_u32() as u8
    }
}

impl Distribution<u16> for StandardUniform {
    #[inline]
    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> u16 {
        rng.next_u32() as u16
    }
}

impl Distribution<u32> for StandardUniform {
    #[inline]
    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> u32 {
        rng.next_u32()
    }
}

impl Distribution<u64> for StandardUniform {
    #[inline]
    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> u64 {
        rng.next_u64()
    }
}

impl Distribution<u128> for StandardUniform {
    #[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
    }
}

macro_rules! impl_int_from_uint {
    ($ty:ty, $uty:ty) => {
        impl Distribution<$ty> for StandardUniform {
            #[inline]
            fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> $ty {
                rng.random::<$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 }

macro_rules! impl_nzint {
    ($ty:ty, $new:path) => {
        impl Distribution<$ty> for StandardUniform {
            fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> $ty {
                loop {
                    if let Some(nz) = $new(rng.random()) {
                        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!(NonZeroI8, NonZeroI8::new);
impl_nzint!(NonZeroI16, NonZeroI16::new);
impl_nzint!(NonZeroI32, NonZeroI32::new);
impl_nzint!(NonZeroI64, NonZeroI64::new);
impl_nzint!(NonZeroI128, NonZeroI128::new);

#[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
impl Distribution<__m128i> for StandardUniform {
    #[inline]
    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> __m128i {
        // NOTE: It's tempting to use the u128 impl here, but confusingly this
        // results in different code (return via rdx, r10 instead of rax, rdx
        // with u128 impl) and is much slower (+130 time).

        let mut buf = [0_u8; core::mem::size_of::<__m128i>()];
        rng.fill_bytes(&mut buf);
        // x86 is little endian so no need for conversion

        // SAFETY: All byte sequences of `buf` represent values of the output type.
        unsafe { core::mem::transmute(buf) }
    }
}

#[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
impl Distribution<__m256i> for StandardUniform {
    #[inline]
    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> __m256i {
        let mut buf = [0_u8; core::mem::size_of::<__m256i>()];
        rng.fill_bytes(&mut buf);
        // x86 is little endian so no need for conversion

        // SAFETY: All byte sequences of `buf` represent values of the output type.
        unsafe { core::mem::transmute(buf) }
    }
}

#[cfg(all(
    any(target_arch = "x86", target_arch = "x86_64"),
    feature = "simd_support"
))]
impl Distribution<__m512i> for StandardUniform {
    #[inline]
    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> __m512i {
        let mut buf = [0_u8; core::mem::size_of::<__m512i>()];
        rng.fill_bytes(&mut buf);
        // x86 is little endian so no need for conversion

        // SAFETY: All byte sequences of `buf` represent values of the output type.
        unsafe { core::mem::transmute(buf) }
    }
}

#[cfg(feature = "simd_support")]
macro_rules! simd_impl {
    ($($ty:ty),+) => {$(
        /// Requires nightly Rust and the [`simd_support`] feature
        ///
        /// [`simd_support`]: https://github.com/rust-random/rand#crate-features
        #[cfg(feature = "simd_support")]
        impl<const LANES: usize> Distribution<Simd<$ty, LANES>> for StandardUniform {
            #[inline]
            fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Simd<$ty, LANES> {
                let mut vec = Simd::default();
                rng.fill(vec.as_mut_array().as_mut_slice());
                vec
            }
        }
    )+};
}

#[cfg(feature = "simd_support")]
simd_impl!(u8, i8, u16, i16, u32, i32, u64, i64);

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_integers() {
        let mut rng = crate::test::rng(806);

        rng.sample::<i8, _>(StandardUniform);
        rng.sample::<i16, _>(StandardUniform);
        rng.sample::<i32, _>(StandardUniform);
        rng.sample::<i64, _>(StandardUniform);
        rng.sample::<i128, _>(StandardUniform);

        rng.sample::<u8, _>(StandardUniform);
        rng.sample::<u16, _>(StandardUniform);
        rng.sample::<u32, _>(StandardUniform);
        rng.sample::<u64, _>(StandardUniform);
        rng.sample::<u128, _>(StandardUniform);
    }

    #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
    #[test]
    fn x86_integers() {
        let mut rng = crate::test::rng(807);

        rng.sample::<__m128i, _>(StandardUniform);
        rng.sample::<__m256i, _>(StandardUniform);
        #[cfg(feature = "simd_support")]
        rng.sample::<__m512i, _>(StandardUniform);
    }

    #[test]
    fn value_stability() {
        fn test_samples<T: Copy + core::fmt::Debug + PartialEq>(zero: T, expected: &[T])
        where
            StandardUniform: Distribution<T>,
        {
            let mut rng = crate::test::rng(807);
            let mut buf = [zero; 3];
            for x in &mut buf {
                *x = rng.sample(StandardUniform);
            }
            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,
            ],
        );

        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(
                u8x4::default(),
                &[
                    u8x4::from([9, 126, 87, 132]),
                    u8x4::from([247, 167, 123, 153]),
                    u8x4::from([111, 149, 73, 120]),
                ],
            );
            test_samples(
                u8x8::default(),
                &[
                    u8x8::from([9, 126, 87, 132, 247, 167, 123, 153]),
                    u8x8::from([111, 149, 73, 120, 68, 171, 98, 223]),
                    u8x8::from([24, 121, 1, 50, 13, 46, 164, 20]),
                ],
            );

            test_samples(
                i64x8::default(),
                &[
                    i64x8::from([
                        -7387126082252079607,
                        -2350127744969763473,
                        1487364411147516184,
                        7895421560427121838,
                        602190064936008898,
                        6022086574635100741,
                        -5080089175222015595,
                        -4066367846667249123,
                    ]),
                    i64x8::from([
                        9180885022207963908,
                        3095981199532211089,
                        6586075293021332726,
                        419343203796414657,
                        3186951873057035255,
                        5287129228749947252,
                        444726432079249540,
                        -1587028029513790706,
                    ]),
                    i64x8::from([
                        6075236523189346388,
                        1351763722368165432,
                        -6192309979959753740,
                        -7697775502176768592,
                        -4482022114172078123,
                        7522501477800909500,
                        -1837258847956201231,
                        -586926753024886735,
                    ]),
                ],
            );
        }
    }
}

Coverage Report

Created: 2026-07-25 06:08

Line	Count	Source
1		// Copyright 2018 Developers of the Rand project.
2		//
3		// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
4		// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
5		// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
6		// option. This file may not be copied, modified, or distributed
7		// except according to those terms.
8
9		//! The implementations of the `StandardUniform` distribution for integer types.
10
11		use crate::distr::{Distribution, StandardUniform};
12		use crate::{Rng, RngExt};
13		#[cfg(all(target_arch = "x86", feature = "simd_support"))]
14		use core::arch::x86::__m512i;
15		#[cfg(target_arch = "x86")]
16		use core::arch::x86::{__m128i, __m256i};
17		#[cfg(all(target_arch = "x86_64", feature = "simd_support"))]
18		use core::arch::x86_64::__m512i;
19		#[cfg(target_arch = "x86_64")]
20		use core::arch::x86_64::{__m128i, __m256i};
21		use core::num::{
22		NonZeroI8, NonZeroI16, NonZeroI32, NonZeroI64, NonZeroI128, NonZeroU8, NonZeroU16, NonZeroU32,
23		NonZeroU64, NonZeroU128,
24		};
25		#[cfg(feature = "simd_support")]
26		use core::simd::*;
27
28		impl Distribution<u8> for StandardUniform {
29		#[inline]
30	0	fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> u8 {
31	0	rng.next_u32() as u8
32	0	}
33		}
34
35		impl Distribution<u16> for StandardUniform {
36		#[inline]
37	0	fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> u16 {
38	0	rng.next_u32() as u16
39	0	} Unexecuted instantiation: <rand::distr::StandardUniform as rand::distr::distribution::Distribution<u16>>::sample::<rand::rngs::thread::ThreadRng> Unexecuted instantiation: <rand::distr::StandardUniform as rand::distr::distribution::Distribution<u16>>::sample::<_>
40		}
41
42		impl Distribution<u32> for StandardUniform {
43		#[inline]
44	0	fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> u32 {
45	0	rng.next_u32()
46	0	} Unexecuted instantiation: <rand::distr::StandardUniform as rand::distr::distribution::Distribution<u32>>::sample::<rand::rngs::thread::ThreadRng> Unexecuted instantiation: <rand::distr::StandardUniform as rand::distr::distribution::Distribution<u32>>::sample::<_>
47		}
48
49		impl Distribution<u64> for StandardUniform {
50		#[inline]
51	0	fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> u64 {
52	0	rng.next_u64()
53	0	}
54		}
55
56		impl Distribution<u128> for StandardUniform {
57		#[inline]
58	0	fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> u128 {
59		// Use LE; we explicitly generate one value before the next.
60	0	let x = u128::from(rng.next_u64());
61	0	let y = u128::from(rng.next_u64());
62	0	(y << 64) \| x
63	0	}
64		}
65
66		macro_rules! impl_int_from_uint {
67		($ty:ty, $uty:ty) => {
68		impl Distribution<$ty> for StandardUniform {
69		#[inline]
70	0	fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> $ty {
71	0	rng.random::<$uty>() as $ty
72	0	} Unexecuted instantiation: <rand::distr::StandardUniform as rand::distr::distribution::Distribution<i8>>::sample::<_> Unexecuted instantiation: <rand::distr::StandardUniform as rand::distr::distribution::Distribution<i16>>::sample::<_> Unexecuted instantiation: <rand::distr::StandardUniform as rand::distr::distribution::Distribution<i32>>::sample::<_> Unexecuted instantiation: <rand::distr::StandardUniform as rand::distr::distribution::Distribution<i64>>::sample::<_> Unexecuted instantiation: <rand::distr::StandardUniform as rand::distr::distribution::Distribution<i128>>::sample::<_>
73		}
74		};
75		}
76
77		impl_int_from_uint! { i8, u8 }
78		impl_int_from_uint! { i16, u16 }
79		impl_int_from_uint! { i32, u32 }
80		impl_int_from_uint! { i64, u64 }
81		impl_int_from_uint! { i128, u128 }
82
83		macro_rules! impl_nzint {
84		($ty:ty, $new:path) => {
85		impl Distribution<$ty> for StandardUniform {
86	0	fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> $ty {
87		loop {
88	0	if let Some(nz) = $new(rng.random()) {
89	0	break nz;
90	0	}
91		}
92	0	} Unexecuted instantiation: <rand::distr::StandardUniform as rand::distr::distribution::Distribution<core::num::nonzero::NonZero<u8>>>::sample::<_> Unexecuted instantiation: <rand::distr::StandardUniform as rand::distr::distribution::Distribution<core::num::nonzero::NonZero<u16>>>::sample::<_> Unexecuted instantiation: <rand::distr::StandardUniform as rand::distr::distribution::Distribution<core::num::nonzero::NonZero<u32>>>::sample::<_> Unexecuted instantiation: <rand::distr::StandardUniform as rand::distr::distribution::Distribution<core::num::nonzero::NonZero<u64>>>::sample::<_> Unexecuted instantiation: <rand::distr::StandardUniform as rand::distr::distribution::Distribution<core::num::nonzero::NonZero<u128>>>::sample::<_> Unexecuted instantiation: <rand::distr::StandardUniform as rand::distr::distribution::Distribution<core::num::nonzero::NonZero<i8>>>::sample::<_> Unexecuted instantiation: <rand::distr::StandardUniform as rand::distr::distribution::Distribution<core::num::nonzero::NonZero<i16>>>::sample::<_> Unexecuted instantiation: <rand::distr::StandardUniform as rand::distr::distribution::Distribution<core::num::nonzero::NonZero<i32>>>::sample::<_> Unexecuted instantiation: <rand::distr::StandardUniform as rand::distr::distribution::Distribution<core::num::nonzero::NonZero<i64>>>::sample::<_> Unexecuted instantiation: <rand::distr::StandardUniform as rand::distr::distribution::Distribution<core::num::nonzero::NonZero<i128>>>::sample::<_>
93		}
94		};
95		}
96
97		impl_nzint!(NonZeroU8, NonZeroU8::new);
98		impl_nzint!(NonZeroU16, NonZeroU16::new);
99		impl_nzint!(NonZeroU32, NonZeroU32::new);
100		impl_nzint!(NonZeroU64, NonZeroU64::new);
101		impl_nzint!(NonZeroU128, NonZeroU128::new);
102
103		impl_nzint!(NonZeroI8, NonZeroI8::new);
104		impl_nzint!(NonZeroI16, NonZeroI16::new);
105		impl_nzint!(NonZeroI32, NonZeroI32::new);
106		impl_nzint!(NonZeroI64, NonZeroI64::new);
107		impl_nzint!(NonZeroI128, NonZeroI128::new);
108
109		#[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
110		impl Distribution<__m128i> for StandardUniform {
111		#[inline]
112	0	fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> __m128i {
113		// NOTE: It's tempting to use the u128 impl here, but confusingly this
114		// results in different code (return via rdx, r10 instead of rax, rdx
115		// with u128 impl) and is much slower (+130 time).
116
117	0	let mut buf = [0_u8; core::mem::size_of::<__m128i>()];
118	0	rng.fill_bytes(&mut buf);
119		// x86 is little endian so no need for conversion
120
121		// SAFETY: All byte sequences of `buf` represent values of the output type.
122	0	unsafe { core::mem::transmute(buf) }
123	0	}
124		}
125
126		#[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
127		impl Distribution<__m256i> for StandardUniform {
128		#[inline]
129	0	fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> __m256i {
130	0	let mut buf = [0_u8; core::mem::size_of::<__m256i>()];
131	0	rng.fill_bytes(&mut buf);
132		// x86 is little endian so no need for conversion
133
134		// SAFETY: All byte sequences of `buf` represent values of the output type.
135	0	unsafe { core::mem::transmute(buf) }
136	0	}
137		}
138
139		#[cfg(all(
140		any(target_arch = "x86", target_arch = "x86_64"),
141		feature = "simd_support"
142		))]
143		impl Distribution<__m512i> for StandardUniform {
144		#[inline]
145		fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> __m512i {
146		let mut buf = [0_u8; core::mem::size_of::<__m512i>()];
147		rng.fill_bytes(&mut buf);
148		// x86 is little endian so no need for conversion
149
150		// SAFETY: All byte sequences of `buf` represent values of the output type.
151		unsafe { core::mem::transmute(buf) }
152		}
153		}
154
155		#[cfg(feature = "simd_support")]
156		macro_rules! simd_impl {
157		($($ty:ty),+) => {$(
158		/// Requires nightly Rust and the [`simd_support`] feature
159		///
160		/// [`simd_support`]: https://github.com/rust-random/rand#crate-features
161		#[cfg(feature = "simd_support")]
162		impl<const LANES: usize> Distribution<Simd<$ty, LANES>> for StandardUniform {
163		#[inline]
164		fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Simd<$ty, LANES> {
165		let mut vec = Simd::default();
166		rng.fill(vec.as_mut_array().as_mut_slice());
167		vec
168		}
169		}
170		)+};
171		}
172
173		#[cfg(feature = "simd_support")]
174		simd_impl!(u8, i8, u16, i16, u32, i32, u64, i64);
175
176		#[cfg(test)]
177		mod tests {
178		use super::*;
179
180		#[test]
181		fn test_integers() {
182		let mut rng = crate::test::rng(806);
183
184		rng.sample::<i8, _>(StandardUniform);
185		rng.sample::<i16, _>(StandardUniform);
186		rng.sample::<i32, _>(StandardUniform);
187		rng.sample::<i64, _>(StandardUniform);
188		rng.sample::<i128, _>(StandardUniform);
189
190		rng.sample::<u8, _>(StandardUniform);
191		rng.sample::<u16, _>(StandardUniform);
192		rng.sample::<u32, _>(StandardUniform);
193		rng.sample::<u64, _>(StandardUniform);
194		rng.sample::<u128, _>(StandardUniform);
195		}
196
197		#[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
198		#[test]
199		fn x86_integers() {
200		let mut rng = crate::test::rng(807);
201
202		rng.sample::<__m128i, _>(StandardUniform);
203		rng.sample::<__m256i, _>(StandardUniform);
204		#[cfg(feature = "simd_support")]
205		rng.sample::<__m512i, _>(StandardUniform);
206		}
207
208		#[test]
209		fn value_stability() {
210		fn test_samples<T: Copy + core::fmt::Debug + PartialEq>(zero: T, expected: &[T])
211		where
212		StandardUniform: Distribution<T>,
213		{
214		let mut rng = crate::test::rng(807);
215		let mut buf = [zero; 3];
216		for x in &mut buf {
217		*x = rng.sample(StandardUniform);
218		}
219		assert_eq!(&buf, expected);
220		}
221
222		test_samples(0u8, &[9, 247, 111]);
223		test_samples(0u16, &[32265, 42999, 38255]);
224		test_samples(0u32, &[2220326409, 2575017975, 2018088303]);
225		test_samples(
226		0u64,
227		&[
228		11059617991457472009,
229		16096616328739788143,
230		1487364411147516184,
231		],
232		);
233		test_samples(
234		0u128,
235		&[
236		296930161868957086625409848350820761097,
237		145644820879247630242265036535529306392,
238		111087889832015897993126088499035356354,
239		],
240		);
241
242		test_samples(0i8, &[9, -9, 111]);
243		// Skip further i* types: they are simple reinterpretation of u* samples
244
245		#[cfg(feature = "simd_support")]
246		{
247		// We only test a sub-set of types here and make assumptions about the rest.
248
249		test_samples(
250		u8x4::default(),
251		&[
252		u8x4::from([9, 126, 87, 132]),
253		u8x4::from([247, 167, 123, 153]),
254		u8x4::from([111, 149, 73, 120]),
255		],
256		);
257		test_samples(
258		u8x8::default(),
259		&[
260		u8x8::from([9, 126, 87, 132, 247, 167, 123, 153]),
261		u8x8::from([111, 149, 73, 120, 68, 171, 98, 223]),
262		u8x8::from([24, 121, 1, 50, 13, 46, 164, 20]),
263		],
264		);
265
266		test_samples(
267		i64x8::default(),
268		&[
269		i64x8::from([
270		-7387126082252079607,
271		-2350127744969763473,
272		1487364411147516184,
273		7895421560427121838,
274		602190064936008898,
275		6022086574635100741,
276		-5080089175222015595,
277		-4066367846667249123,
278		]),
279		i64x8::from([
280		9180885022207963908,
281		3095981199532211089,
282		6586075293021332726,
283		419343203796414657,
284		3186951873057035255,
285		5287129228749947252,
286		444726432079249540,
287		-1587028029513790706,
288		]),
289		i64x8::from([
290		6075236523189346388,
291		1351763722368165432,
292		-6192309979959753740,
293		-7697775502176768592,
294		-4482022114172078123,
295		7522501477800909500,
296		-1837258847956201231,
297		-586926753024886735,
298		]),
299		],
300		);
301		}
302		}
303		}