From 6bf0a5cb5034a7e684dcc3500e841785237ce2dd Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 19:32:43 +0200 Subject: Adding upstream version 1:115.7.0. Signed-off-by: Daniel Baumann --- third_party/rust/generic-array/src/lib.rs | 679 ++++++++++++++++++++++++++++++ 1 file changed, 679 insertions(+) create mode 100644 third_party/rust/generic-array/src/lib.rs (limited to 'third_party/rust/generic-array/src/lib.rs') diff --git a/third_party/rust/generic-array/src/lib.rs b/third_party/rust/generic-array/src/lib.rs new file mode 100644 index 0000000000..43ab26ff56 --- /dev/null +++ b/third_party/rust/generic-array/src/lib.rs @@ -0,0 +1,679 @@ +//! This crate implements a structure that can be used as a generic array type. +//! Core Rust array types `[T; N]` can't be used generically with +//! respect to `N`, so for example this: +//! +//! ```rust{compile_fail} +//! struct Foo { +//! data: [T; N] +//! } +//! ``` +//! +//! won't work. +//! +//! **generic-array** exports a `GenericArray` type, which lets +//! the above be implemented as: +//! +//! ```rust +//! use generic_array::{ArrayLength, GenericArray}; +//! +//! struct Foo> { +//! data: GenericArray +//! } +//! ``` +//! +//! The `ArrayLength` trait is implemented by default for +//! [unsigned integer types](../typenum/uint/index.html) from +//! [typenum](../typenum/index.html): +//! +//! ```rust +//! # use generic_array::{ArrayLength, GenericArray}; +//! use generic_array::typenum::U5; +//! +//! struct Foo> { +//! data: GenericArray +//! } +//! +//! # fn main() { +//! let foo = Foo::{data: GenericArray::default()}; +//! # } +//! ``` +//! +//! For example, `GenericArray` would work almost like `[T; 5]`: +//! +//! ```rust +//! # use generic_array::{ArrayLength, GenericArray}; +//! use generic_array::typenum::U5; +//! +//! struct Foo> { +//! data: GenericArray +//! } +//! +//! # fn main() { +//! let foo = Foo::{data: GenericArray::default()}; +//! # } +//! ``` +//! +//! For ease of use, an `arr!` macro is provided - example below: +//! +//! ``` +//! # #[macro_use] +//! # extern crate generic_array; +//! # extern crate typenum; +//! # fn main() { +//! let array = arr![u32; 1, 2, 3]; +//! assert_eq!(array[2], 3); +//! # } +//! ``` + +#![deny(missing_docs)] +#![deny(meta_variable_misuse)] +#![no_std] + +#[cfg(feature = "serde")] +extern crate serde; + +#[cfg(feature = "zeroize")] +extern crate zeroize; + +#[cfg(test)] +extern crate bincode; + +pub extern crate typenum; + +mod hex; +mod impls; + +#[cfg(feature = "serde")] +mod impl_serde; + +#[cfg(feature = "zeroize")] +mod impl_zeroize; + +use core::iter::FromIterator; +use core::marker::PhantomData; +use core::mem::{MaybeUninit, ManuallyDrop}; +use core::ops::{Deref, DerefMut}; +use core::{mem, ptr, slice}; +use typenum::bit::{B0, B1}; +use typenum::uint::{UInt, UTerm, Unsigned}; + +#[cfg_attr(test, macro_use)] +pub mod arr; +pub mod functional; +pub mod iter; +pub mod sequence; + +use self::functional::*; +pub use self::iter::GenericArrayIter; +use self::sequence::*; + +/// Trait making `GenericArray` work, marking types to be used as length of an array +pub unsafe trait ArrayLength: Unsigned { + /// Associated type representing the array type for the number + type ArrayType; +} + +unsafe impl ArrayLength for UTerm { + #[doc(hidden)] + type ArrayType = [T; 0]; +} + +/// Internal type used to generate a struct of appropriate size +#[allow(dead_code)] +#[repr(C)] +#[doc(hidden)] +pub struct GenericArrayImplEven { + parent1: U, + parent2: U, + _marker: PhantomData, +} + +impl Clone for GenericArrayImplEven { + fn clone(&self) -> GenericArrayImplEven { + GenericArrayImplEven { + parent1: self.parent1.clone(), + parent2: self.parent2.clone(), + _marker: PhantomData, + } + } +} + +impl Copy for GenericArrayImplEven {} + +/// Internal type used to generate a struct of appropriate size +#[allow(dead_code)] +#[repr(C)] +#[doc(hidden)] +pub struct GenericArrayImplOdd { + parent1: U, + parent2: U, + data: T, +} + +impl Clone for GenericArrayImplOdd { + fn clone(&self) -> GenericArrayImplOdd { + GenericArrayImplOdd { + parent1: self.parent1.clone(), + parent2: self.parent2.clone(), + data: self.data.clone(), + } + } +} + +impl Copy for GenericArrayImplOdd {} + +unsafe impl> ArrayLength for UInt { + #[doc(hidden)] + type ArrayType = GenericArrayImplEven; +} + +unsafe impl> ArrayLength for UInt { + #[doc(hidden)] + type ArrayType = GenericArrayImplOdd; +} + +/// Struct representing a generic array - `GenericArray` works like [T; N] +#[allow(dead_code)] +#[repr(transparent)] +pub struct GenericArray> { + data: U::ArrayType, +} + +unsafe impl> Send for GenericArray {} +unsafe impl> Sync for GenericArray {} + +impl Deref for GenericArray +where + N: ArrayLength, +{ + type Target = [T]; + + #[inline(always)] + fn deref(&self) -> &[T] { + unsafe { slice::from_raw_parts(self as *const Self as *const T, N::USIZE) } + } +} + +impl DerefMut for GenericArray +where + N: ArrayLength, +{ + #[inline(always)] + fn deref_mut(&mut self) -> &mut [T] { + unsafe { slice::from_raw_parts_mut(self as *mut Self as *mut T, N::USIZE) } + } +} + +/// Creates an array one element at a time using a mutable iterator +/// you can write to with `ptr::write`. +/// +/// Increment the position while iterating to mark off created elements, +/// which will be dropped if `into_inner` is not called. +#[doc(hidden)] +pub struct ArrayBuilder> { + array: MaybeUninit>, + position: usize, +} + +impl> ArrayBuilder { + #[doc(hidden)] + #[inline] + pub unsafe fn new() -> ArrayBuilder { + ArrayBuilder { + array: MaybeUninit::uninit(), + position: 0, + } + } + + /// Creates a mutable iterator for writing to the array using `ptr::write`. + /// + /// Increment the position value given as a mutable reference as you iterate + /// to mark how many elements have been created. + #[doc(hidden)] + #[inline] + pub unsafe fn iter_position(&mut self) -> (slice::IterMut, &mut usize) { + ((&mut *self.array.as_mut_ptr()).iter_mut(), &mut self.position) + } + + /// When done writing (assuming all elements have been written to), + /// get the inner array. + #[doc(hidden)] + #[inline] + pub unsafe fn into_inner(self) -> GenericArray { + let array = ptr::read(&self.array); + + mem::forget(self); + + array.assume_init() + } +} + +impl> Drop for ArrayBuilder { + fn drop(&mut self) { + if mem::needs_drop::() { + unsafe { + for value in &mut (&mut *self.array.as_mut_ptr())[..self.position] { + ptr::drop_in_place(value); + } + } + } + } +} + +/// Consumes an array. +/// +/// Increment the position while iterating and any leftover elements +/// will be dropped if position does not go to N +#[doc(hidden)] +pub struct ArrayConsumer> { + array: ManuallyDrop>, + position: usize, +} + +impl> ArrayConsumer { + #[doc(hidden)] + #[inline] + pub unsafe fn new(array: GenericArray) -> ArrayConsumer { + ArrayConsumer { + array: ManuallyDrop::new(array), + position: 0, + } + } + + /// Creates an iterator and mutable reference to the internal position + /// to keep track of consumed elements. + /// + /// Increment the position as you iterate to mark off consumed elements + #[doc(hidden)] + #[inline] + pub unsafe fn iter_position(&mut self) -> (slice::Iter, &mut usize) { + (self.array.iter(), &mut self.position) + } +} + +impl> Drop for ArrayConsumer { + fn drop(&mut self) { + if mem::needs_drop::() { + for value in &mut self.array[self.position..N::USIZE] { + unsafe { + ptr::drop_in_place(value); + } + } + } + } +} + +impl<'a, T: 'a, N> IntoIterator for &'a GenericArray +where + N: ArrayLength, +{ + type IntoIter = slice::Iter<'a, T>; + type Item = &'a T; + + fn into_iter(self: &'a GenericArray) -> Self::IntoIter { + self.as_slice().iter() + } +} + +impl<'a, T: 'a, N> IntoIterator for &'a mut GenericArray +where + N: ArrayLength, +{ + type IntoIter = slice::IterMut<'a, T>; + type Item = &'a mut T; + + fn into_iter(self: &'a mut GenericArray) -> Self::IntoIter { + self.as_mut_slice().iter_mut() + } +} + +impl FromIterator for GenericArray +where + N: ArrayLength, +{ + fn from_iter(iter: I) -> GenericArray + where + I: IntoIterator, + { + unsafe { + let mut destination = ArrayBuilder::new(); + + { + let (destination_iter, position) = destination.iter_position(); + + iter.into_iter() + .zip(destination_iter) + .for_each(|(src, dst)| { + ptr::write(dst, src); + + *position += 1; + }); + } + + if destination.position < N::USIZE { + from_iter_length_fail(destination.position, N::USIZE); + } + + destination.into_inner() + } + } +} + +#[inline(never)] +#[cold] +fn from_iter_length_fail(length: usize, expected: usize) -> ! { + panic!( + "GenericArray::from_iter received {} elements but expected {}", + length, expected + ); +} + +unsafe impl GenericSequence for GenericArray +where + N: ArrayLength, + Self: IntoIterator, +{ + type Length = N; + type Sequence = Self; + + fn generate(mut f: F) -> GenericArray + where + F: FnMut(usize) -> T, + { + unsafe { + let mut destination = ArrayBuilder::new(); + + { + let (destination_iter, position) = destination.iter_position(); + + destination_iter.enumerate().for_each(|(i, dst)| { + ptr::write(dst, f(i)); + + *position += 1; + }); + } + + destination.into_inner() + } + } + + #[doc(hidden)] + fn inverted_zip( + self, + lhs: GenericArray, + mut f: F, + ) -> MappedSequence, B, U> + where + GenericArray: + GenericSequence + MappedGenericSequence, + Self: MappedGenericSequence, + Self::Length: ArrayLength + ArrayLength, + F: FnMut(B, Self::Item) -> U, + { + unsafe { + let mut left = ArrayConsumer::new(lhs); + let mut right = ArrayConsumer::new(self); + + let (left_array_iter, left_position) = left.iter_position(); + let (right_array_iter, right_position) = right.iter_position(); + + FromIterator::from_iter(left_array_iter.zip(right_array_iter).map(|(l, r)| { + let left_value = ptr::read(l); + let right_value = ptr::read(r); + + *left_position += 1; + *right_position += 1; + + f(left_value, right_value) + })) + } + } + + #[doc(hidden)] + fn inverted_zip2(self, lhs: Lhs, mut f: F) -> MappedSequence + where + Lhs: GenericSequence + MappedGenericSequence, + Self: MappedGenericSequence, + Self::Length: ArrayLength + ArrayLength, + F: FnMut(Lhs::Item, Self::Item) -> U, + { + unsafe { + let mut right = ArrayConsumer::new(self); + + let (right_array_iter, right_position) = right.iter_position(); + + FromIterator::from_iter( + lhs.into_iter() + .zip(right_array_iter) + .map(|(left_value, r)| { + let right_value = ptr::read(r); + + *right_position += 1; + + f(left_value, right_value) + }), + ) + } + } +} + +unsafe impl MappedGenericSequence for GenericArray +where + N: ArrayLength + ArrayLength, + GenericArray: GenericSequence, +{ + type Mapped = GenericArray; +} + +unsafe impl FunctionalSequence for GenericArray +where + N: ArrayLength, + Self: GenericSequence, +{ + fn map(self, mut f: F) -> MappedSequence + where + Self::Length: ArrayLength, + Self: MappedGenericSequence, + F: FnMut(T) -> U, + { + unsafe { + let mut source = ArrayConsumer::new(self); + + let (array_iter, position) = source.iter_position(); + + FromIterator::from_iter(array_iter.map(|src| { + let value = ptr::read(src); + + *position += 1; + + f(value) + })) + } + } + + #[inline] + fn zip(self, rhs: Rhs, f: F) -> MappedSequence + where + Self: MappedGenericSequence, + Rhs: MappedGenericSequence>, + Self::Length: ArrayLength + ArrayLength, + Rhs: GenericSequence, + F: FnMut(T, Rhs::Item) -> U, + { + rhs.inverted_zip(self, f) + } + + fn fold(self, init: U, mut f: F) -> U + where + F: FnMut(U, T) -> U, + { + unsafe { + let mut source = ArrayConsumer::new(self); + + let (array_iter, position) = source.iter_position(); + + array_iter.fold(init, |acc, src| { + let value = ptr::read(src); + + *position += 1; + + f(acc, value) + }) + } + } +} + +impl GenericArray +where + N: ArrayLength, +{ + /// Extracts a slice containing the entire array. + #[inline] + pub fn as_slice(&self) -> &[T] { + self.deref() + } + + /// Extracts a mutable slice containing the entire array. + #[inline] + pub fn as_mut_slice(&mut self) -> &mut [T] { + self.deref_mut() + } + + /// Converts slice to a generic array reference with inferred length; + /// + /// Length of the slice must be equal to the length of the array. + #[inline] + pub fn from_slice(slice: &[T]) -> &GenericArray { + slice.into() + } + + /// Converts mutable slice to a mutable generic array reference + /// + /// Length of the slice must be equal to the length of the array. + #[inline] + pub fn from_mut_slice(slice: &mut [T]) -> &mut GenericArray { + slice.into() + } +} + +impl<'a, T, N: ArrayLength> From<&'a [T]> for &'a GenericArray { + /// Converts slice to a generic array reference with inferred length; + /// + /// Length of the slice must be equal to the length of the array. + #[inline] + fn from(slice: &[T]) -> &GenericArray { + assert_eq!(slice.len(), N::USIZE); + + unsafe { &*(slice.as_ptr() as *const GenericArray) } + } +} + +impl<'a, T, N: ArrayLength> From<&'a mut [T]> for &'a mut GenericArray { + /// Converts mutable slice to a mutable generic array reference + /// + /// Length of the slice must be equal to the length of the array. + #[inline] + fn from(slice: &mut [T]) -> &mut GenericArray { + assert_eq!(slice.len(), N::USIZE); + + unsafe { &mut *(slice.as_mut_ptr() as *mut GenericArray) } + } +} + +impl GenericArray +where + N: ArrayLength, +{ + /// Construct a `GenericArray` from a slice by cloning its content + /// + /// Length of the slice must be equal to the length of the array + #[inline] + pub fn clone_from_slice(list: &[T]) -> GenericArray { + Self::from_exact_iter(list.iter().cloned()) + .expect("Slice must be the same length as the array") + } +} + +impl GenericArray +where + N: ArrayLength, +{ + /// Creates a new `GenericArray` instance from an iterator with a specific size. + /// + /// Returns `None` if the size is not equal to the number of elements in the `GenericArray`. + pub fn from_exact_iter(iter: I) -> Option + where + I: IntoIterator, + { + let mut iter = iter.into_iter(); + + unsafe { + let mut destination = ArrayBuilder::new(); + + { + let (destination_iter, position) = destination.iter_position(); + + destination_iter.zip(&mut iter).for_each(|(dst, src)| { + ptr::write(dst, src); + + *position += 1; + }); + + // The iterator produced fewer than `N` elements. + if *position != N::USIZE { + return None; + } + + // The iterator produced more than `N` elements. + if iter.next().is_some() { + return None; + } + } + + Some(destination.into_inner()) + } + } +} + +/// A reimplementation of the `transmute` function, avoiding problems +/// when the compiler can't prove equal sizes. +#[inline] +#[doc(hidden)] +pub unsafe fn transmute(a: A) -> B { + let a = ManuallyDrop::new(a); + ::core::ptr::read(&*a as *const A as *const B) +} + +#[cfg(test)] +mod test { + // Compile with: + // cargo rustc --lib --profile test --release -- + // -C target-cpu=native -C opt-level=3 --emit asm + // and view the assembly to make sure test_assembly generates + // SIMD instructions instead of a naive loop. + + #[inline(never)] + pub fn black_box(val: T) -> T { + use core::{mem, ptr}; + + let ret = unsafe { ptr::read_volatile(&val) }; + mem::forget(val); + ret + } + + #[test] + fn test_assembly() { + use crate::functional::*; + + let a = black_box(arr![i32; 1, 3, 5, 7]); + let b = black_box(arr![i32; 2, 4, 6, 8]); + + let c = (&a).zip(b, |l, r| l + r); + + let d = a.fold(0, |a, x| a + x); + + assert_eq!(c, arr![i32; 3, 7, 11, 15]); + + assert_eq!(d, 16); + } +} -- cgit v1.2.3