Initial vendor packages
Signed-off-by: Valentin Popov <valentin@popov.link>
This commit is contained in:
218
vendor/fastrand/src/global_rng.rs
vendored
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218
vendor/fastrand/src/global_rng.rs
vendored
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//! A global, thread-local random number generator.
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use crate::Rng;
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use std::cell::Cell;
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use std::ops::RangeBounds;
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// Chosen by fair roll of the dice.
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const DEFAULT_RNG_SEED: u64 = 0xef6f79ed30ba75a;
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impl Default for Rng {
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/// Initialize the `Rng` from the system's random number generator.
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///
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/// This is equivalent to [`Rng::new()`].
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#[inline]
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fn default() -> Rng {
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Rng::new()
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}
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}
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impl Rng {
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/// Creates a new random number generator.
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#[inline]
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pub fn new() -> Rng {
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try_with_rng(Rng::fork).unwrap_or_else(|_| Rng::with_seed(0x4d595df4d0f33173))
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}
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}
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thread_local! {
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static RNG: Cell<Rng> = Cell::new(Rng(random_seed().unwrap_or(DEFAULT_RNG_SEED)));
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}
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/// Run an operation with the current thread-local generator.
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#[inline]
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fn with_rng<R>(f: impl FnOnce(&mut Rng) -> R) -> R {
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RNG.with(|rng| {
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let current = rng.replace(Rng(0));
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let mut restore = RestoreOnDrop { rng, current };
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f(&mut restore.current)
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})
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}
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/// Try to run an operation with the current thread-local generator.
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#[inline]
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fn try_with_rng<R>(f: impl FnOnce(&mut Rng) -> R) -> Result<R, std::thread::AccessError> {
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RNG.try_with(|rng| {
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let current = rng.replace(Rng(0));
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let mut restore = RestoreOnDrop { rng, current };
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f(&mut restore.current)
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})
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}
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/// Make sure the original RNG is restored even on panic.
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struct RestoreOnDrop<'a> {
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rng: &'a Cell<Rng>,
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current: Rng,
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}
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impl Drop for RestoreOnDrop<'_> {
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fn drop(&mut self) {
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self.rng.set(Rng(self.current.0));
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}
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}
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/// Initializes the thread-local generator with the given seed.
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#[inline]
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pub fn seed(seed: u64) {
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with_rng(|r| r.seed(seed));
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}
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/// Gives back **current** seed that is being held by the thread-local generator.
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#[inline]
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pub fn get_seed() -> u64 {
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with_rng(|r| r.get_seed())
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}
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/// Generates a random `bool`.
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#[inline]
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pub fn bool() -> bool {
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with_rng(|r| r.bool())
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}
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/// Generates a random `char` in ranges a-z and A-Z.
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#[inline]
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pub fn alphabetic() -> char {
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with_rng(|r| r.alphabetic())
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}
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/// Generates a random `char` in ranges a-z, A-Z and 0-9.
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#[inline]
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pub fn alphanumeric() -> char {
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with_rng(|r| r.alphanumeric())
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}
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/// Generates a random `char` in range a-z.
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#[inline]
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pub fn lowercase() -> char {
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with_rng(|r| r.lowercase())
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}
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/// Generates a random `char` in range A-Z.
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#[inline]
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pub fn uppercase() -> char {
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with_rng(|r| r.uppercase())
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}
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/// Choose an item from an iterator at random.
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///
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/// This function may have an unexpected result if the `len()` property of the
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/// iterator does not match the actual number of items in the iterator. If
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/// the iterator is empty, this returns `None`.
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#[inline]
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pub fn choice<I>(iter: I) -> Option<I::Item>
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where
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I: IntoIterator,
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I::IntoIter: ExactSizeIterator,
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{
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with_rng(|r| r.choice(iter))
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}
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/// Generates a random digit in the given `base`.
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///
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/// Digits are represented by `char`s in ranges 0-9 and a-z.
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///
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/// Panics if the base is zero or greater than 36.
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#[inline]
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pub fn digit(base: u32) -> char {
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with_rng(|r| r.digit(base))
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}
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/// Shuffles a slice randomly.
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#[inline]
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pub fn shuffle<T>(slice: &mut [T]) {
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with_rng(|r| r.shuffle(slice))
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}
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macro_rules! integer {
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($t:tt, $doc:tt) => {
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#[doc = $doc]
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///
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/// Panics if the range is empty.
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#[inline]
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pub fn $t(range: impl RangeBounds<$t>) -> $t {
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with_rng(|r| r.$t(range))
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}
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};
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}
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integer!(u8, "Generates a random `u8` in the given range.");
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integer!(i8, "Generates a random `i8` in the given range.");
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integer!(u16, "Generates a random `u16` in the given range.");
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integer!(i16, "Generates a random `i16` in the given range.");
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integer!(u32, "Generates a random `u32` in the given range.");
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integer!(i32, "Generates a random `i32` in the given range.");
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integer!(u64, "Generates a random `u64` in the given range.");
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integer!(i64, "Generates a random `i64` in the given range.");
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integer!(u128, "Generates a random `u128` in the given range.");
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integer!(i128, "Generates a random `i128` in the given range.");
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integer!(usize, "Generates a random `usize` in the given range.");
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integer!(isize, "Generates a random `isize` in the given range.");
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integer!(char, "Generates a random `char` in the given range.");
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/// Generates a random `f32` in range `0..1`.
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pub fn f32() -> f32 {
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with_rng(|r| r.f32())
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}
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/// Generates a random `f64` in range `0..1`.
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pub fn f64() -> f64 {
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with_rng(|r| r.f64())
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}
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/// Collects `amount` values at random from the iterator into a vector.
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pub fn choose_multiple<T: Iterator>(source: T, amount: usize) -> Vec<T::Item> {
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with_rng(|rng| rng.choose_multiple(source, amount))
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}
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#[cfg(not(all(
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any(target_arch = "wasm32", target_arch = "wasm64"),
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target_os = "unknown"
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)))]
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fn random_seed() -> Option<u64> {
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use std::collections::hash_map::DefaultHasher;
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use std::hash::{Hash, Hasher};
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use std::thread;
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use std::time::Instant;
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let mut hasher = DefaultHasher::new();
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Instant::now().hash(&mut hasher);
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thread::current().id().hash(&mut hasher);
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let hash = hasher.finish();
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Some((hash << 1) | 1)
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}
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#[cfg(all(
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any(target_arch = "wasm32", target_arch = "wasm64"),
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target_os = "unknown",
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feature = "js"
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))]
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fn random_seed() -> Option<u64> {
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// TODO(notgull): Failures should be logged somewhere.
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let mut seed = [0u8; 8];
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getrandom::getrandom(&mut seed).ok()?;
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Some(u64::from_ne_bytes(seed))
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}
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#[cfg(all(
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any(target_arch = "wasm32", target_arch = "wasm64"),
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target_os = "unknown",
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not(feature = "js")
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))]
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fn random_seed() -> Option<u64> {
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None
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}
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692
vendor/fastrand/src/lib.rs
vendored
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692
vendor/fastrand/src/lib.rs
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@@ -0,0 +1,692 @@
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//! A simple and fast random number generator.
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//!
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//! The implementation uses [Wyrand](https://github.com/wangyi-fudan/wyhash), a simple and fast
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//! generator but **not** cryptographically secure.
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//!
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//! # Examples
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//!
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//! Flip a coin:
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//!
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//! ```
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//! if fastrand::bool() {
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//! println!("heads");
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//! } else {
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//! println!("tails");
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//! }
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//! ```
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//!
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//! Generate a random `i32`:
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//!
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//! ```
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//! let num = fastrand::i32(..);
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//! ```
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//!
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//! Choose a random element in an array:
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//!
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//! ```
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//! let v = vec![1, 2, 3, 4, 5];
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//! let i = fastrand::usize(..v.len());
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//! let elem = v[i];
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//! ```
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//!
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//! Sample values from an array with `O(n)` complexity (`n` is the length of array):
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//!
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//! ```
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//! fastrand::choose_multiple(vec![1, 4, 5].iter(), 2);
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//! fastrand::choose_multiple(0..20, 12);
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//! ```
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//!
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//!
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//! Shuffle an array:
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//!
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//! ```
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//! let mut v = vec![1, 2, 3, 4, 5];
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//! fastrand::shuffle(&mut v);
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//! ```
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//!
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//! Generate a random [`Vec`] or [`String`]:
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//!
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//! ```
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//! use std::iter::repeat_with;
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//!
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//! let v: Vec<i32> = repeat_with(|| fastrand::i32(..)).take(10).collect();
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//! let s: String = repeat_with(fastrand::alphanumeric).take(10).collect();
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//! ```
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//!
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//! To get reproducible results on every run, initialize the generator with a seed:
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//!
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//! ```
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//! // Pick an arbitrary number as seed.
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//! fastrand::seed(7);
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//!
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//! // Now this prints the same number on every run:
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//! println!("{}", fastrand::u32(..));
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//! ```
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//!
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//! To be more efficient, create a new [`Rng`] instance instead of using the thread-local
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//! generator:
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//!
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//! ```
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//! use std::iter::repeat_with;
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//!
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//! let mut rng = fastrand::Rng::new();
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//! let mut bytes: Vec<u8> = repeat_with(|| rng.u8(..)).take(10_000).collect();
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//! ```
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//!
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//! This crate aims to expose a core set of useful randomness primitives. For more niche algorithms,
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//! consider using the [`fastrand-contrib`] crate alongside this one.
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//!
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//! # Features
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//!
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//! - `std` (enabled by default): Enables the `std` library. This is required for the global
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//! generator and global entropy. Without this feature, [`Rng`] can only be instantiated using
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//! the [`with_seed`](Rng::with_seed) method.
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//! - `js`: Assumes that WebAssembly targets are being run in a JavaScript environment. See the
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//! [WebAssembly Notes](#webassembly-notes) section for more information.
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//!
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//! # WebAssembly Notes
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//!
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//! For non-WASI WASM targets, there is additional sublety to consider when utilizing the global RNG.
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//! By default, `std` targets will use entropy sources in the standard library to seed the global RNG.
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//! However, these sources are not available by default on WASM targets outside of WASI.
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//!
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//! If the `js` feature is enabled, this crate will assume that it is running in a JavaScript
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//! environment. At this point, the [`getrandom`] crate will be used in order to access the available
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//! entropy sources and seed the global RNG. If the `js` feature is not enabled, the global RNG will
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//! use a predefined seed.
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//!
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//! [`fastrand-contrib`]: https://crates.io/crates/fastrand-contrib
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//! [`getrandom`]: https://crates.io/crates/getrandom
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#![cfg_attr(not(feature = "std"), no_std)]
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#![cfg_attr(docsrs, feature(doc_cfg))]
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#![forbid(unsafe_code)]
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#![warn(missing_docs, missing_debug_implementations, rust_2018_idioms)]
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#![doc(
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html_favicon_url = "https://raw.githubusercontent.com/smol-rs/smol/master/assets/images/logo_fullsize_transparent.png"
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)]
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#![doc(
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html_logo_url = "https://raw.githubusercontent.com/smol-rs/smol/master/assets/images/logo_fullsize_transparent.png"
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)]
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#[cfg(feature = "alloc")]
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extern crate alloc;
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use core::convert::{TryFrom, TryInto};
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use core::ops::{Bound, RangeBounds};
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#[cfg(feature = "alloc")]
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use alloc::vec::Vec;
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#[cfg(feature = "std")]
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#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
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mod global_rng;
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#[cfg(feature = "std")]
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pub use global_rng::*;
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/// A random number generator.
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#[derive(Debug, PartialEq, Eq)]
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pub struct Rng(u64);
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impl Clone for Rng {
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/// Clones the generator by creating a new generator with the same seed.
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fn clone(&self) -> Rng {
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Rng::with_seed(self.0)
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}
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}
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impl Rng {
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/// Generates a random `u32`.
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#[inline]
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fn gen_u32(&mut self) -> u32 {
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self.gen_u64() as u32
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}
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/// Generates a random `u64`.
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#[inline]
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fn gen_u64(&mut self) -> u64 {
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let s = self.0.wrapping_add(0xA0761D6478BD642F);
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self.0 = s;
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let t = u128::from(s) * u128::from(s ^ 0xE7037ED1A0B428DB);
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(t as u64) ^ (t >> 64) as u64
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}
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/// Generates a random `u128`.
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#[inline]
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fn gen_u128(&mut self) -> u128 {
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(u128::from(self.gen_u64()) << 64) | u128::from(self.gen_u64())
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}
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/// Generates a random `u32` in `0..n`.
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#[inline]
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fn gen_mod_u32(&mut self, n: u32) -> u32 {
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// Adapted from: https://lemire.me/blog/2016/06/30/fast-random-shuffling/
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let mut r = self.gen_u32();
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let mut hi = mul_high_u32(r, n);
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let mut lo = r.wrapping_mul(n);
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if lo < n {
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let t = n.wrapping_neg() % n;
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while lo < t {
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r = self.gen_u32();
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hi = mul_high_u32(r, n);
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lo = r.wrapping_mul(n);
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}
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}
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hi
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}
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/// Generates a random `u64` in `0..n`.
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#[inline]
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fn gen_mod_u64(&mut self, n: u64) -> u64 {
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// Adapted from: https://lemire.me/blog/2016/06/30/fast-random-shuffling/
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let mut r = self.gen_u64();
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let mut hi = mul_high_u64(r, n);
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let mut lo = r.wrapping_mul(n);
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if lo < n {
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let t = n.wrapping_neg() % n;
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while lo < t {
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r = self.gen_u64();
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hi = mul_high_u64(r, n);
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lo = r.wrapping_mul(n);
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}
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}
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hi
|
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}
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/// Generates a random `u128` in `0..n`.
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#[inline]
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fn gen_mod_u128(&mut self, n: u128) -> u128 {
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// Adapted from: https://lemire.me/blog/2016/06/30/fast-random-shuffling/
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let mut r = self.gen_u128();
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let mut hi = mul_high_u128(r, n);
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let mut lo = r.wrapping_mul(n);
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if lo < n {
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let t = n.wrapping_neg() % n;
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while lo < t {
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r = self.gen_u128();
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hi = mul_high_u128(r, n);
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lo = r.wrapping_mul(n);
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}
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}
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hi
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||||
}
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}
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/// Computes `(a * b) >> 32`.
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#[inline]
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fn mul_high_u32(a: u32, b: u32) -> u32 {
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(((a as u64) * (b as u64)) >> 32) as u32
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}
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/// Computes `(a * b) >> 64`.
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#[inline]
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fn mul_high_u64(a: u64, b: u64) -> u64 {
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(((a as u128) * (b as u128)) >> 64) as u64
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}
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/// Computes `(a * b) >> 128`.
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#[inline]
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fn mul_high_u128(a: u128, b: u128) -> u128 {
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// Adapted from: https://stackoverflow.com/a/28904636
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let a_lo = a as u64 as u128;
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let a_hi = (a >> 64) as u64 as u128;
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let b_lo = b as u64 as u128;
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let b_hi = (b >> 64) as u64 as u128;
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let carry = (a_lo * b_lo) >> 64;
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let carry = ((a_hi * b_lo) as u64 as u128 + (a_lo * b_hi) as u64 as u128 + carry) >> 64;
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a_hi * b_hi + ((a_hi * b_lo) >> 64) + ((a_lo * b_hi) >> 64) + carry
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||||
}
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||||
macro_rules! rng_integer {
|
||||
($t:tt, $unsigned_t:tt, $gen:tt, $mod:tt, $doc:tt) => {
|
||||
#[doc = $doc]
|
||||
///
|
||||
/// Panics if the range is empty.
|
||||
#[inline]
|
||||
pub fn $t(&mut self, range: impl RangeBounds<$t>) -> $t {
|
||||
let panic_empty_range = || {
|
||||
panic!(
|
||||
"empty range: {:?}..{:?}",
|
||||
range.start_bound(),
|
||||
range.end_bound()
|
||||
)
|
||||
};
|
||||
|
||||
let low = match range.start_bound() {
|
||||
Bound::Unbounded => core::$t::MIN,
|
||||
Bound::Included(&x) => x,
|
||||
Bound::Excluded(&x) => x.checked_add(1).unwrap_or_else(panic_empty_range),
|
||||
};
|
||||
|
||||
let high = match range.end_bound() {
|
||||
Bound::Unbounded => core::$t::MAX,
|
||||
Bound::Included(&x) => x,
|
||||
Bound::Excluded(&x) => x.checked_sub(1).unwrap_or_else(panic_empty_range),
|
||||
};
|
||||
|
||||
if low > high {
|
||||
panic_empty_range();
|
||||
}
|
||||
|
||||
if low == core::$t::MIN && high == core::$t::MAX {
|
||||
self.$gen() as $t
|
||||
} else {
|
||||
let len = high.wrapping_sub(low).wrapping_add(1);
|
||||
low.wrapping_add(self.$mod(len as $unsigned_t as _) as $t)
|
||||
}
|
||||
}
|
||||
};
|
||||
}
|
||||
|
||||
impl Rng {
|
||||
/// Creates a new random number generator with the initial seed.
|
||||
#[inline]
|
||||
#[must_use = "this creates a new instance of `Rng`; if you want to initialize the thread-local generator, use `fastrand::seed()` instead"]
|
||||
pub fn with_seed(seed: u64) -> Self {
|
||||
let mut rng = Rng(0);
|
||||
|
||||
rng.seed(seed);
|
||||
rng
|
||||
}
|
||||
|
||||
/// Clones the generator by deterministically deriving a new generator based on the initial
|
||||
/// seed.
|
||||
///
|
||||
/// This function can be used to create a new generator that is a "spinoff" of the old
|
||||
/// generator. The new generator will not produce the same sequence of values as the
|
||||
/// old generator.
|
||||
///
|
||||
/// # Example
|
||||
///
|
||||
/// ```
|
||||
/// // Seed two generators equally, and clone both of them.
|
||||
/// let mut base1 = fastrand::Rng::with_seed(0x4d595df4d0f33173);
|
||||
/// base1.bool(); // Use the generator once.
|
||||
///
|
||||
/// let mut base2 = fastrand::Rng::with_seed(0x4d595df4d0f33173);
|
||||
/// base2.bool(); // Use the generator once.
|
||||
///
|
||||
/// let mut rng1 = base1.fork();
|
||||
/// let mut rng2 = base2.fork();
|
||||
///
|
||||
/// println!("rng1 returns {}", rng1.u32(..));
|
||||
/// println!("rng2 returns {}", rng2.u32(..));
|
||||
/// ```
|
||||
#[inline]
|
||||
#[must_use = "this creates a new instance of `Rng`"]
|
||||
pub fn fork(&mut self) -> Self {
|
||||
Rng::with_seed(self.gen_u64())
|
||||
}
|
||||
|
||||
/// Generates a random `char` in ranges a-z and A-Z.
|
||||
#[inline]
|
||||
pub fn alphabetic(&mut self) -> char {
|
||||
const CHARS: &[u8] = b"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
|
||||
*self.choice(CHARS).unwrap() as char
|
||||
}
|
||||
|
||||
/// Generates a random `char` in ranges a-z, A-Z and 0-9.
|
||||
#[inline]
|
||||
pub fn alphanumeric(&mut self) -> char {
|
||||
const CHARS: &[u8] = b"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
|
||||
*self.choice(CHARS).unwrap() as char
|
||||
}
|
||||
|
||||
/// Generates a random `bool`.
|
||||
#[inline]
|
||||
pub fn bool(&mut self) -> bool {
|
||||
self.u8(..) % 2 == 0
|
||||
}
|
||||
|
||||
/// Generates a random digit in the given `base`.
|
||||
///
|
||||
/// Digits are represented by `char`s in ranges 0-9 and a-z.
|
||||
///
|
||||
/// Panics if the base is zero or greater than 36.
|
||||
#[inline]
|
||||
pub fn digit(&mut self, base: u32) -> char {
|
||||
if base == 0 {
|
||||
panic!("base cannot be zero");
|
||||
}
|
||||
if base > 36 {
|
||||
panic!("base cannot be larger than 36");
|
||||
}
|
||||
let num = self.u8(..base as u8);
|
||||
if num < 10 {
|
||||
(b'0' + num) as char
|
||||
} else {
|
||||
(b'a' + num - 10) as char
|
||||
}
|
||||
}
|
||||
|
||||
/// Generates a random `f32` in range `0..1`.
|
||||
pub fn f32(&mut self) -> f32 {
|
||||
let b = 32;
|
||||
let f = core::f32::MANTISSA_DIGITS - 1;
|
||||
f32::from_bits((1 << (b - 2)) - (1 << f) + (self.u32(..) >> (b - f))) - 1.0
|
||||
}
|
||||
|
||||
/// Generates a random `f64` in range `0..1`.
|
||||
pub fn f64(&mut self) -> f64 {
|
||||
let b = 64;
|
||||
let f = core::f64::MANTISSA_DIGITS - 1;
|
||||
f64::from_bits((1 << (b - 2)) - (1 << f) + (self.u64(..) >> (b - f))) - 1.0
|
||||
}
|
||||
|
||||
/// Collects `amount` values at random from the iterator into a vector.
|
||||
///
|
||||
/// The length of the returned vector equals `amount` unless the iterator
|
||||
/// contains insufficient elements, in which case it equals the number of
|
||||
/// elements available.
|
||||
///
|
||||
/// Complexity is `O(n)` where `n` is the length of the iterator.
|
||||
#[cfg(feature = "alloc")]
|
||||
#[cfg_attr(docsrs, doc(cfg(feature = "alloc")))]
|
||||
pub fn choose_multiple<T: Iterator>(&mut self, mut source: T, amount: usize) -> Vec<T::Item> {
|
||||
// Adapted from: https://docs.rs/rand/latest/rand/seq/trait.IteratorRandom.html#method.choose_multiple
|
||||
let mut reservoir = Vec::with_capacity(amount);
|
||||
|
||||
reservoir.extend(source.by_ref().take(amount));
|
||||
|
||||
// Continue unless the iterator was exhausted
|
||||
//
|
||||
// note: this prevents iterators that "restart" from causing problems.
|
||||
// If the iterator stops once, then so do we.
|
||||
if reservoir.len() == amount {
|
||||
for (i, elem) in source.enumerate() {
|
||||
let end = i + 1 + amount;
|
||||
let k = self.usize(0..end);
|
||||
if let Some(slot) = reservoir.get_mut(k) {
|
||||
*slot = elem;
|
||||
}
|
||||
}
|
||||
} else {
|
||||
// If less than one third of the `Vec` was used, reallocate
|
||||
// so that the unused space is not wasted. There is a corner
|
||||
// case where `amount` was much less than `self.len()`.
|
||||
if reservoir.capacity() > 3 * reservoir.len() {
|
||||
reservoir.shrink_to_fit();
|
||||
}
|
||||
}
|
||||
reservoir
|
||||
}
|
||||
|
||||
rng_integer!(
|
||||
i8,
|
||||
u8,
|
||||
gen_u32,
|
||||
gen_mod_u32,
|
||||
"Generates a random `i8` in the given range."
|
||||
);
|
||||
|
||||
rng_integer!(
|
||||
i16,
|
||||
u16,
|
||||
gen_u32,
|
||||
gen_mod_u32,
|
||||
"Generates a random `i16` in the given range."
|
||||
);
|
||||
|
||||
rng_integer!(
|
||||
i32,
|
||||
u32,
|
||||
gen_u32,
|
||||
gen_mod_u32,
|
||||
"Generates a random `i32` in the given range."
|
||||
);
|
||||
|
||||
rng_integer!(
|
||||
i64,
|
||||
u64,
|
||||
gen_u64,
|
||||
gen_mod_u64,
|
||||
"Generates a random `i64` in the given range."
|
||||
);
|
||||
|
||||
rng_integer!(
|
||||
i128,
|
||||
u128,
|
||||
gen_u128,
|
||||
gen_mod_u128,
|
||||
"Generates a random `i128` in the given range."
|
||||
);
|
||||
|
||||
#[cfg(target_pointer_width = "16")]
|
||||
rng_integer!(
|
||||
isize,
|
||||
usize,
|
||||
gen_u32,
|
||||
gen_mod_u32,
|
||||
"Generates a random `isize` in the given range."
|
||||
);
|
||||
#[cfg(target_pointer_width = "32")]
|
||||
rng_integer!(
|
||||
isize,
|
||||
usize,
|
||||
gen_u32,
|
||||
gen_mod_u32,
|
||||
"Generates a random `isize` in the given range."
|
||||
);
|
||||
#[cfg(target_pointer_width = "64")]
|
||||
rng_integer!(
|
||||
isize,
|
||||
usize,
|
||||
gen_u64,
|
||||
gen_mod_u64,
|
||||
"Generates a random `isize` in the given range."
|
||||
);
|
||||
|
||||
/// Generates a random `char` in range a-z.
|
||||
#[inline]
|
||||
pub fn lowercase(&mut self) -> char {
|
||||
const CHARS: &[u8] = b"abcdefghijklmnopqrstuvwxyz";
|
||||
*self.choice(CHARS).unwrap() as char
|
||||
}
|
||||
|
||||
/// Initializes this generator with the given seed.
|
||||
#[inline]
|
||||
pub fn seed(&mut self, seed: u64) {
|
||||
self.0 = seed;
|
||||
}
|
||||
|
||||
/// Gives back **current** seed that is being held by this generator.
|
||||
#[inline]
|
||||
pub fn get_seed(&self) -> u64 {
|
||||
self.0
|
||||
}
|
||||
|
||||
/// Choose an item from an iterator at random.
|
||||
///
|
||||
/// This function may have an unexpected result if the `len()` property of the
|
||||
/// iterator does not match the actual number of items in the iterator. If
|
||||
/// the iterator is empty, this returns `None`.
|
||||
#[inline]
|
||||
pub fn choice<I>(&mut self, iter: I) -> Option<I::Item>
|
||||
where
|
||||
I: IntoIterator,
|
||||
I::IntoIter: ExactSizeIterator,
|
||||
{
|
||||
let mut iter = iter.into_iter();
|
||||
|
||||
// Get the item at a random index.
|
||||
let len = iter.len();
|
||||
if len == 0 {
|
||||
return None;
|
||||
}
|
||||
let index = self.usize(0..len);
|
||||
|
||||
iter.nth(index)
|
||||
}
|
||||
|
||||
/// Shuffles a slice randomly.
|
||||
#[inline]
|
||||
pub fn shuffle<T>(&mut self, slice: &mut [T]) {
|
||||
for i in 1..slice.len() {
|
||||
slice.swap(i, self.usize(..=i));
|
||||
}
|
||||
}
|
||||
|
||||
/// Fill a byte slice with random data.
|
||||
#[inline]
|
||||
pub fn fill(&mut self, slice: &mut [u8]) {
|
||||
// We fill the slice by chunks of 8 bytes, or one block of
|
||||
// WyRand output per new state.
|
||||
let mut chunks = slice.chunks_exact_mut(core::mem::size_of::<u64>());
|
||||
for chunk in chunks.by_ref() {
|
||||
let n = self.gen_u64().to_ne_bytes();
|
||||
// Safe because the chunks are always 8 bytes exactly.
|
||||
chunk.copy_from_slice(&n);
|
||||
}
|
||||
|
||||
let remainder = chunks.into_remainder();
|
||||
|
||||
// Any remainder will always be less than 8 bytes.
|
||||
if !remainder.is_empty() {
|
||||
// Generate one last block of 8 bytes of entropy
|
||||
let n = self.gen_u64().to_ne_bytes();
|
||||
|
||||
// Use the remaining length to copy from block
|
||||
remainder.copy_from_slice(&n[..remainder.len()]);
|
||||
}
|
||||
}
|
||||
|
||||
rng_integer!(
|
||||
u8,
|
||||
u8,
|
||||
gen_u32,
|
||||
gen_mod_u32,
|
||||
"Generates a random `u8` in the given range."
|
||||
);
|
||||
|
||||
rng_integer!(
|
||||
u16,
|
||||
u16,
|
||||
gen_u32,
|
||||
gen_mod_u32,
|
||||
"Generates a random `u16` in the given range."
|
||||
);
|
||||
|
||||
rng_integer!(
|
||||
u32,
|
||||
u32,
|
||||
gen_u32,
|
||||
gen_mod_u32,
|
||||
"Generates a random `u32` in the given range."
|
||||
);
|
||||
|
||||
rng_integer!(
|
||||
u64,
|
||||
u64,
|
||||
gen_u64,
|
||||
gen_mod_u64,
|
||||
"Generates a random `u64` in the given range."
|
||||
);
|
||||
|
||||
rng_integer!(
|
||||
u128,
|
||||
u128,
|
||||
gen_u128,
|
||||
gen_mod_u128,
|
||||
"Generates a random `u128` in the given range."
|
||||
);
|
||||
|
||||
#[cfg(target_pointer_width = "16")]
|
||||
rng_integer!(
|
||||
usize,
|
||||
usize,
|
||||
gen_u32,
|
||||
gen_mod_u32,
|
||||
"Generates a random `usize` in the given range."
|
||||
);
|
||||
#[cfg(target_pointer_width = "32")]
|
||||
rng_integer!(
|
||||
usize,
|
||||
usize,
|
||||
gen_u32,
|
||||
gen_mod_u32,
|
||||
"Generates a random `usize` in the given range."
|
||||
);
|
||||
#[cfg(target_pointer_width = "64")]
|
||||
rng_integer!(
|
||||
usize,
|
||||
usize,
|
||||
gen_u64,
|
||||
gen_mod_u64,
|
||||
"Generates a random `usize` in the given range."
|
||||
);
|
||||
#[cfg(target_pointer_width = "128")]
|
||||
rng_integer!(
|
||||
usize,
|
||||
usize,
|
||||
gen_u128,
|
||||
gen_mod_u128,
|
||||
"Generates a random `usize` in the given range."
|
||||
);
|
||||
|
||||
/// Generates a random `char` in range A-Z.
|
||||
#[inline]
|
||||
pub fn uppercase(&mut self) -> char {
|
||||
const CHARS: &[u8] = b"ABCDEFGHIJKLMNOPQRSTUVWXYZ";
|
||||
*self.choice(CHARS).unwrap() as char
|
||||
}
|
||||
|
||||
/// Generates a random `char` in the given range.
|
||||
///
|
||||
/// Panics if the range is empty.
|
||||
#[inline]
|
||||
pub fn char(&mut self, range: impl RangeBounds<char>) -> char {
|
||||
let panic_empty_range = || {
|
||||
panic!(
|
||||
"empty range: {:?}..{:?}",
|
||||
range.start_bound(),
|
||||
range.end_bound()
|
||||
)
|
||||
};
|
||||
|
||||
let surrogate_start = 0xd800u32;
|
||||
let surrogate_len = 0x800u32;
|
||||
|
||||
let low = match range.start_bound() {
|
||||
Bound::Unbounded => 0u8 as char,
|
||||
Bound::Included(&x) => x,
|
||||
Bound::Excluded(&x) => {
|
||||
let scalar = if x as u32 == surrogate_start - 1 {
|
||||
surrogate_start + surrogate_len
|
||||
} else {
|
||||
x as u32 + 1
|
||||
};
|
||||
char::try_from(scalar).unwrap_or_else(|_| panic_empty_range())
|
||||
}
|
||||
};
|
||||
|
||||
let high = match range.end_bound() {
|
||||
Bound::Unbounded => core::char::MAX,
|
||||
Bound::Included(&x) => x,
|
||||
Bound::Excluded(&x) => {
|
||||
let scalar = if x as u32 == surrogate_start + surrogate_len {
|
||||
surrogate_start - 1
|
||||
} else {
|
||||
(x as u32).wrapping_sub(1)
|
||||
};
|
||||
char::try_from(scalar).unwrap_or_else(|_| panic_empty_range())
|
||||
}
|
||||
};
|
||||
|
||||
if low > high {
|
||||
panic_empty_range();
|
||||
}
|
||||
|
||||
let gap = if (low as u32) < surrogate_start && (high as u32) >= surrogate_start {
|
||||
surrogate_len
|
||||
} else {
|
||||
0
|
||||
};
|
||||
let range = high as u32 - low as u32 - gap;
|
||||
let mut val = self.u32(0..=range) + low as u32;
|
||||
if val >= surrogate_start {
|
||||
val += gap;
|
||||
}
|
||||
val.try_into().unwrap()
|
||||
}
|
||||
}
|
||||
Reference in New Issue
Block a user