From 698f8c2f01ea549d77d7dc3338a12e04c11057b9 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Wed, 17 Apr 2024 14:02:58 +0200 Subject: Adding upstream version 1.64.0+dfsg1. Signed-off-by: Daniel Baumann --- vendor/rand-0.7.3/src/distributions/other.rs | 291 +++++++++++++++++++++++++++ 1 file changed, 291 insertions(+) create mode 100644 vendor/rand-0.7.3/src/distributions/other.rs (limited to 'vendor/rand-0.7.3/src/distributions/other.rs') diff --git a/vendor/rand-0.7.3/src/distributions/other.rs b/vendor/rand-0.7.3/src/distributions/other.rs new file mode 100644 index 000000000..c95060e51 --- /dev/null +++ b/vendor/rand-0.7.3/src/distributions/other.rs @@ -0,0 +1,291 @@ +// Copyright 2018 Developers of the Rand project. +// +// Licensed under the Apache License, Version 2.0 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +//! The implementations of the `Standard` distribution for other built-in types. + +use core::char; +use core::num::Wrapping; + +use crate::distributions::{Distribution, Standard, Uniform}; +use crate::Rng; + +// ----- Sampling distributions ----- + +/// Sample a `char`, uniformly distributed over ASCII letters and numbers: +/// a-z, A-Z and 0-9. +/// +/// # Example +/// +/// ``` +/// use std::iter; +/// use rand::{Rng, thread_rng}; +/// use rand::distributions::Alphanumeric; +/// +/// let mut rng = thread_rng(); +/// let chars: String = iter::repeat(()) +/// .map(|()| rng.sample(Alphanumeric)) +/// .take(7) +/// .collect(); +/// println!("Random chars: {}", chars); +/// ``` +#[derive(Debug)] +pub struct Alphanumeric; + + +// ----- Implementations of distributions ----- + +impl Distribution for Standard { + #[inline] + fn sample(&self, rng: &mut R) -> char { + // A valid `char` is either in the interval `[0, 0xD800)` or + // `(0xDFFF, 0x11_0000)`. All `char`s must therefore be in + // `[0, 0x11_0000)` but not in the "gap" `[0xD800, 0xDFFF]` which is + // reserved for surrogates. This is the size of that gap. + const GAP_SIZE: u32 = 0xDFFF - 0xD800 + 1; + + // Uniform::new(0, 0x11_0000 - GAP_SIZE) can also be used but it + // seemed slower. + let range = Uniform::new(GAP_SIZE, 0x11_0000); + + let mut n = range.sample(rng); + if n <= 0xDFFF { + n -= GAP_SIZE; + } + unsafe { char::from_u32_unchecked(n) } + } +} + +impl Distribution for Alphanumeric { + fn sample(&self, rng: &mut R) -> char { + const RANGE: u32 = 26 + 26 + 10; + const GEN_ASCII_STR_CHARSET: &[u8] = b"ABCDEFGHIJKLMNOPQRSTUVWXYZ\ + abcdefghijklmnopqrstuvwxyz\ + 0123456789"; + // We can pick from 62 characters. This is so close to a power of 2, 64, + // that we can do better than `Uniform`. Use a simple bitshift and + // rejection sampling. We do not use a bitmask, because for small RNGs + // the most significant bits are usually of higher quality. + loop { + let var = rng.next_u32() >> (32 - 6); + if var < RANGE { + return GEN_ASCII_STR_CHARSET[var as usize] as char; + } + } + } +} + +impl Distribution for Standard { + #[inline] + fn sample(&self, rng: &mut R) -> bool { + // We can compare against an arbitrary bit of an u32 to get a bool. + // Because the least significant bits of a lower quality RNG can have + // simple patterns, we compare against the most significant bit. This is + // easiest done using a sign test. + (rng.next_u32() as i32) < 0 + } +} + +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 ),* > + Distribution<( $( $tyvar ),* , )> + for Standard + where $( Standard: Distribution<$tyvar> ),* + { + #[inline] + fn sample(&self, _rng: &mut R) -> ( $( $tyvar ),* , ) { + ( + // use the $tyvar's to get the appropriate number of + // repeats (they're not actually needed) + $( + _rng.gen::<$tyvar>() + ),* + , + ) + } + } + } +} + +impl Distribution<()> for Standard { + #[allow(clippy::unused_unit)] + #[inline] + fn sample(&self, _: &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 { + // recursive, given at least one type parameter: + {$n:expr, $t:ident, $($ts:ident,)*} => { + array_impl!{($n - 1), $($ts,)*} + + impl Distribution<[T; $n]> for Standard where Standard: Distribution { + #[inline] + fn sample(&self, _rng: &mut R) -> [T; $n] { + [_rng.gen::<$t>(), $(_rng.gen::<$ts>()),*] + } + } + }; + // empty case: + {$n:expr,} => { + impl Distribution<[T; $n]> for Standard { + fn sample(&self, _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 Distribution> for Standard +where Standard: Distribution +{ + #[inline] + fn sample(&self, rng: &mut R) -> Option { + // UFCS is needed here: https://github.com/rust-lang/rust/issues/24066 + if rng.gen::() { + Some(rng.gen()) + } else { + None + } + } +} + +impl Distribution> for Standard +where Standard: Distribution +{ + #[inline] + fn sample(&self, rng: &mut R) -> Wrapping { + Wrapping(rng.gen()) + } +} + + +#[cfg(test)] +mod tests { + use super::*; + use crate::RngCore; + #[cfg(all(not(feature = "std"), feature = "alloc"))] use alloc::string::String; + + #[test] + fn test_misc() { + let rng: &mut dyn RngCore = &mut crate::test::rng(820); + + rng.sample::(Standard); + rng.sample::(Standard); + } + + #[cfg(feature = "alloc")] + #[test] + fn test_chars() { + use core::iter; + let mut rng = crate::test::rng(805); + + // Test by generating a relatively large number of chars, so we also + // take the rejection sampling path. + let word: String = iter::repeat(()) + .map(|()| rng.gen::()) + .take(1000) + .collect(); + assert!(word.len() != 0); + } + + #[test] + fn test_alphanumeric() { + let mut rng = crate::test::rng(806); + + // Test by generating a relatively large number of chars, so we also + // take the rejection sampling path. + let mut incorrect = false; + for _ in 0..100 { + let c = rng.sample(Alphanumeric); + incorrect |= !((c >= '0' && c <= '9') || + (c >= 'A' && c <= 'Z') || + (c >= 'a' && c <= 'z') ); + } + assert!(incorrect == false); + } + + #[test] + fn value_stability() { + fn test_samples>( + distr: &D, zero: T, expected: &[T], + ) { + let mut rng = crate::test::rng(807); + let mut buf = [zero; 5]; + for x in &mut buf { + *x = rng.sample(&distr); + } + assert_eq!(&buf, expected); + } + + test_samples(&Standard, 'a', &[ + '\u{8cdac}', + '\u{a346a}', + '\u{80120}', + '\u{ed692}', + '\u{35888}', + ]); + test_samples(&Alphanumeric, 'a', &['h', 'm', 'e', '3', 'M']); + test_samples(&Standard, false, &[true, true, false, true, false]); + test_samples(&Standard, None as Option, &[ + Some(true), + None, + Some(false), + None, + Some(false), + ]); + test_samples(&Standard, Wrapping(0i32), &[ + Wrapping(-2074640887), + Wrapping(-1719949321), + Wrapping(2018088303), + Wrapping(-547181756), + Wrapping(838957336), + ]); + + // We test only sub-sets of tuple and array impls + test_samples(&Standard, (), &[(), (), (), (), ()]); + test_samples(&Standard, (false,), &[ + (true,), + (true,), + (false,), + (true,), + (false,), + ]); + test_samples(&Standard, (false, false), &[ + (true, true), + (false, true), + (false, false), + (true, false), + (false, false), + ]); + + test_samples(&Standard, [0u8; 0], &[[], [], [], [], []]); + test_samples(&Standard, [0u8; 3], &[ + [9, 247, 111], + [68, 24, 13], + [174, 19, 194], + [172, 69, 213], + [149, 207, 29], + ]); + } +} -- cgit v1.2.3