diff options
Diffstat (limited to '')
-rw-r--r-- | vendor/generic-array-0.12.4/src/lib.rs | 632 |
1 files changed, 632 insertions, 0 deletions
diff --git a/vendor/generic-array-0.12.4/src/lib.rs b/vendor/generic-array-0.12.4/src/lib.rs new file mode 100644 index 000000000..e98e8fd58 --- /dev/null +++ b/vendor/generic-array-0.12.4/src/lib.rs @@ -0,0 +1,632 @@ +//! This crate implements a structure that can be used as a generic array type.use +//! Core Rust array types `[T; N]` can't be used generically with +//! respect to `N`, so for example this: +//! +//! ```{should_fail} +//! struct Foo<T, N> { +//! data: [T; N] +//! } +//! ``` +//! +//! won't work. +//! +//! **generic-array** exports a `GenericArray<T,N>` type, which lets +//! the above be implemented as: +//! +//! ``` +//! # use generic_array::{ArrayLength, GenericArray}; +//! struct Foo<T, N: ArrayLength<T>> { +//! data: GenericArray<T,N> +//! } +//! ``` +//! +//! The `ArrayLength<T>` trait is implemented by default for +//! [unsigned integer types](../typenum/uint/index.html) from +//! [typenum](../typenum/index.html). +//! +//! 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)] +#![no_std] + +#[cfg(feature = "serde")] +extern crate serde; + +#[cfg(test)] +extern crate bincode; + +pub extern crate typenum; + +mod hex; +mod impls; + +#[cfg(feature = "serde")] +pub mod impl_serde; + +use core::iter::FromIterator; +use core::marker::PhantomData; +use core::mem::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 functional::*; +pub use iter::GenericArrayIter; +use sequence::*; + +/// Trait making `GenericArray` work, marking types to be used as length of an array +pub unsafe trait ArrayLength<T>: Unsigned { + /// Associated type representing the array type for the number + type ArrayType; +} + +unsafe impl<T> ArrayLength<T> for UTerm { + #[doc(hidden)] + type ArrayType = (); +} + +/// Internal type used to generate a struct of appropriate size +#[allow(dead_code)] +#[repr(C)] +#[doc(hidden)] +pub struct GenericArrayImplEven<T, U> { + parent1: U, + parent2: U, + _marker: PhantomData<T>, +} + +impl<T: Clone, U: Clone> Clone for GenericArrayImplEven<T, U> { + fn clone(&self) -> GenericArrayImplEven<T, U> { + GenericArrayImplEven { + parent1: self.parent1.clone(), + parent2: self.parent2.clone(), + _marker: PhantomData, + } + } +} + +impl<T: Copy, U: Copy> Copy for GenericArrayImplEven<T, U> {} + +/// Internal type used to generate a struct of appropriate size +#[allow(dead_code)] +#[repr(C)] +#[doc(hidden)] +pub struct GenericArrayImplOdd<T, U> { + parent1: U, + parent2: U, + data: T, +} + +impl<T: Clone, U: Clone> Clone for GenericArrayImplOdd<T, U> { + fn clone(&self) -> GenericArrayImplOdd<T, U> { + GenericArrayImplOdd { + parent1: self.parent1.clone(), + parent2: self.parent2.clone(), + data: self.data.clone(), + } + } +} + +impl<T: Copy, U: Copy> Copy for GenericArrayImplOdd<T, U> {} + +unsafe impl<T, N: ArrayLength<T>> ArrayLength<T> for UInt<N, B0> { + #[doc(hidden)] + type ArrayType = GenericArrayImplEven<T, N::ArrayType>; +} + +unsafe impl<T, N: ArrayLength<T>> ArrayLength<T> for UInt<N, B1> { + #[doc(hidden)] + type ArrayType = GenericArrayImplOdd<T, N::ArrayType>; +} + +/// Struct representing a generic array - `GenericArray<T, N>` works like [T; N] +#[allow(dead_code)] +pub struct GenericArray<T, U: ArrayLength<T>> { + data: U::ArrayType, +} + +unsafe impl<T: Send, N: ArrayLength<T>> Send for GenericArray<T, N> {} +unsafe impl<T: Sync, N: ArrayLength<T>> Sync for GenericArray<T, N> {} + +impl<T, N> Deref for GenericArray<T, N> +where + N: ArrayLength<T>, +{ + type Target = [T]; + + #[inline(always)] + fn deref(&self) -> &[T] { + unsafe { slice::from_raw_parts(self as *const Self as *const T, N::to_usize()) } + } +} + +impl<T, N> DerefMut for GenericArray<T, N> +where + N: ArrayLength<T>, +{ + #[inline(always)] + fn deref_mut(&mut self) -> &mut [T] { + unsafe { slice::from_raw_parts_mut(self as *mut Self as *mut T, N::to_usize()) } + } +} + +/// Creates an array one element at a time using a mutable iterator +/// you can write to with `ptr::write`. +/// +/// Incremenent the position while iterating to mark off created elements, +/// which will be dropped if `into_inner` is not called. +#[doc(hidden)] +pub struct ArrayBuilder<T, N: ArrayLength<T>> { + array: ManuallyDrop<GenericArray<T, N>>, + position: usize, +} + +impl<T, N: ArrayLength<T>> ArrayBuilder<T, N> { + #[doc(hidden)] + #[inline] + pub unsafe fn new() -> ArrayBuilder<T, N> { + ArrayBuilder { + array: ManuallyDrop::new(mem::uninitialized()), + 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<T>, &mut usize) { + (self.array.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<T, N> { + let array = ptr::read(&self.array); + + mem::forget(self); + + ManuallyDrop::into_inner(array) + } +} + +impl<T, N: ArrayLength<T>> Drop for ArrayBuilder<T, N> { + fn drop(&mut self) { + for value in &mut self.array[..self.position] { + unsafe { + 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<T, N: ArrayLength<T>> { + array: ManuallyDrop<GenericArray<T, N>>, + position: usize, +} + +impl<T, N: ArrayLength<T>> ArrayConsumer<T, N> { + #[doc(hidden)] + #[inline] + pub unsafe fn new(array: GenericArray<T, N>) -> ArrayConsumer<T, N> { + 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<T>, &mut usize) { + (self.array.iter(), &mut self.position) + } +} + +impl<T, N: ArrayLength<T>> Drop for ArrayConsumer<T, N> { + fn drop(&mut self) { + for value in &mut self.array[self.position..N::to_usize()] { + unsafe { + ptr::drop_in_place(value); + } + } + } +} + +impl<'a, T: 'a, N> IntoIterator for &'a GenericArray<T, N> +where + N: ArrayLength<T>, +{ + type IntoIter = slice::Iter<'a, T>; + type Item = &'a T; + + fn into_iter(self: &'a GenericArray<T, N>) -> Self::IntoIter { + self.as_slice().iter() + } +} + +impl<'a, T: 'a, N> IntoIterator for &'a mut GenericArray<T, N> +where + N: ArrayLength<T>, +{ + type IntoIter = slice::IterMut<'a, T>; + type Item = &'a mut T; + + fn into_iter(self: &'a mut GenericArray<T, N>) -> Self::IntoIter { + self.as_mut_slice().iter_mut() + } +} + +impl<T, N> FromIterator<T> for GenericArray<T, N> +where + N: ArrayLength<T>, +{ + fn from_iter<I>(iter: I) -> GenericArray<T, N> + where + I: IntoIterator<Item = T>, + { + unsafe { + let mut destination = ArrayBuilder::new(); + + { + let (destination_iter, position) = destination.iter_position(); + + for (src, dst) in iter.into_iter().zip(destination_iter) { + ptr::write(dst, src); + + *position += 1; + } + } + + if destination.position < N::to_usize() { + from_iter_length_fail(destination.position, N::to_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<T, N> GenericSequence<T> for GenericArray<T, N> +where + N: ArrayLength<T>, + Self: IntoIterator<Item = T>, +{ + type Length = N; + type Sequence = Self; + + fn generate<F>(mut f: F) -> GenericArray<T, N> + where + F: FnMut(usize) -> T, + { + unsafe { + let mut destination = ArrayBuilder::new(); + + { + let (destination_iter, position) = destination.iter_position(); + + for (i, dst) in destination_iter.enumerate() { + ptr::write(dst, f(i)); + + *position += 1; + } + } + + destination.into_inner() + } + } + + #[doc(hidden)] + fn inverted_zip<B, U, F>( + self, + lhs: GenericArray<B, Self::Length>, + mut f: F, + ) -> MappedSequence<GenericArray<B, Self::Length>, B, U> + where + GenericArray<B, Self::Length>: + GenericSequence<B, Length = Self::Length> + MappedGenericSequence<B, U>, + Self: MappedGenericSequence<T, U>, + Self::Length: ArrayLength<B> + ArrayLength<U>, + 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<B, Lhs, U, F>(self, lhs: Lhs, mut f: F) -> MappedSequence<Lhs, B, U> + where + Lhs: GenericSequence<B, Length = Self::Length> + MappedGenericSequence<B, U>, + Self: MappedGenericSequence<T, U>, + Self::Length: ArrayLength<B> + ArrayLength<U>, + 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<T, U, N> MappedGenericSequence<T, U> for GenericArray<T, N> +where + N: ArrayLength<T> + ArrayLength<U>, + GenericArray<U, N>: GenericSequence<U, Length = N>, +{ + type Mapped = GenericArray<U, N>; +} + +unsafe impl<T, N> FunctionalSequence<T> for GenericArray<T, N> +where + N: ArrayLength<T>, + Self: GenericSequence<T, Item = T, Length = N>, +{ + fn map<U, F>(self, mut f: F) -> MappedSequence<Self, T, U> + where + Self::Length: ArrayLength<U>, + Self: MappedGenericSequence<T, U>, + 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<B, Rhs, U, F>(self, rhs: Rhs, f: F) -> MappedSequence<Self, T, U> + where + Self: MappedGenericSequence<T, U>, + Rhs: MappedGenericSequence<B, U, Mapped = MappedSequence<Self, T, U>>, + Self::Length: ArrayLength<B> + ArrayLength<U>, + Rhs: GenericSequence<B, Length = Self::Length>, + F: FnMut(T, Rhs::Item) -> U, + { + rhs.inverted_zip(self, f) + } + + fn fold<U, F>(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<T, N> GenericArray<T, N> +where + N: ArrayLength<T>, +{ + /// 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<T, N> { + 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<T, N> { + slice.into() + } +} + +impl<'a, T, N: ArrayLength<T>> From<&'a [T]> for &'a GenericArray<T, N> { + /// 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<T, N> { + assert_eq!(slice.len(), N::to_usize()); + + unsafe { &*(slice.as_ptr() as *const GenericArray<T, N>) } + } +} + +impl<'a, T, N: ArrayLength<T>> From<&'a mut [T]> for &'a mut GenericArray<T, N> { + /// 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<T, N> { + assert_eq!(slice.len(), N::to_usize()); + + unsafe { &mut *(slice.as_mut_ptr() as *mut GenericArray<T, N>) } + } +} + +impl<T: Clone, N> GenericArray<T, N> +where + N: ArrayLength<T>, +{ + /// 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<T, N> { + Self::from_exact_iter(list.iter().cloned()) + .expect("Slice must be the same length as the array") + } +} + +impl<T, N> GenericArray<T, N> +where + N: ArrayLength<T>, +{ + /// Creates a new `GenericArray` instance from an iterator with a known exact size. + /// + /// Returns `None` if the size is not equal to the number of elements in the `GenericArray`. + pub fn from_exact_iter<I>(iter: I) -> Option<Self> + where + I: IntoIterator<Item = T>, + <I as IntoIterator>::IntoIter: ExactSizeIterator, + { + let iter = iter.into_iter(); + + if iter.len() == N::to_usize() { + unsafe { + let mut destination = ArrayBuilder::new(); + + { + let (destination_iter, position) = destination.iter_position(); + + for (dst, src) in destination_iter.zip(iter.into_iter()) { + ptr::write(dst, src); + + *position += 1; + } + } + + Some(destination.into_inner()) + } + } else { + None + } + } +} + +/// A reimplementation of the `transmute` function, avoiding problems +/// when the compiler can't prove equal sizes. +#[inline] +#[doc(hidden)] +pub unsafe fn transmute<A, B>(a: A) -> B { + let b = ::core::ptr::read(&a as *const A as *const B); + ::core::mem::forget(a); + 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 niave loop. + + #[inline(never)] + pub fn black_box<T>(val: T) -> T { + use core::{mem, ptr}; + + let ret = unsafe { ptr::read_volatile(&val) }; + mem::forget(val); + ret + } + + #[test] + fn test_assembly() { + use 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); + } +} |