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//! 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<T, N> {↩
//! data: [T; N]↩
//! }↩
//! ```↩
//!↩
//! won't work.↩
//!↩
//! **generic-array** exports a `GenericArray<T,N>` type, which lets↩
//! the above be implemented as:↩
//!↩
//! ```rust↩
//! 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):↩
//!↩
//! ```rust↩
//! # use generic_array::{ArrayLength, GenericArray};↩
//! use generic_array::typenum::U5;↩
//!↩
//! struct Foo<N: ArrayLength<i32>> {↩
//! data: GenericArray<i32, N>↩
//! }↩
//!↩
//! # fn main() {↩
//! let foo = Foo::<U5>{data: GenericArray::default()};↩
//! # }↩
//! ```↩
//!↩
//! For example, `GenericArray<T, U5>` would work almost like `[T; 5]`:↩
//!↩
//! ```rust↩
//! # use generic_array::{ArrayLength, GenericArray};↩
//! use generic_array::typenum::U5;↩
//!↩
//! struct Foo<T, N: ArrayLength<T>> {↩
//! data: GenericArray<T, N>↩
//! }↩
//!↩
//! # fn main() {↩
//! let foo = Foo::<i32, U5>{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<T>: Unsigned {↩
/// Associated type representing the array type for the number↩
type ArrayType;↩
}↩
↩
unsafe impl<T> ArrayLength<T> 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<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)]↩
#[repr(transparent)]↩
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::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::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<T, N: ArrayLength<T>> {↩
array: MaybeUninit<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: 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<T>, &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<T, N> {↩
let array = ptr::read(&self.array);↩
↩
mem::forget(self);↩
↩
array.assume_init()↩
}↩
}↩
↩
impl<T, N: ArrayLength<T>> Drop for ArrayBuilder<T, N> {↩
fn drop(&mut self) {↩
if mem::needs_drop::<T>() {↩
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<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) {↩
if mem::needs_drop::<T>() {↩
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<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();↩
↩
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<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();↩
↩
destination_iter.enumerate().for_each(|(i, dst)| {↩
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::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::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 specific 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>,↩
{↩
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, B>(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<T>(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);↩
}↩
}↩