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use core::{cmp::Ordering, fmt, hash, iter::FromIterator, mem::MaybeUninit, ops, ptr, slice};
/// A fixed capacity [`Vec`](https://doc.rust-lang.org/std/vec/struct.Vec.html)
///
/// # Examples
///
/// ```
/// use heapless::Vec;
///
///
/// // A vector with a fixed capacity of 8 elements allocated on the stack
/// let mut vec = Vec::<_, 8>::new();
/// vec.push(1);
/// vec.push(2);
///
/// assert_eq!(vec.len(), 2);
/// assert_eq!(vec[0], 1);
///
/// assert_eq!(vec.pop(), Some(2));
/// assert_eq!(vec.len(), 1);
///
/// vec[0] = 7;
/// assert_eq!(vec[0], 7);
///
/// vec.extend([1, 2, 3].iter().cloned());
///
/// for x in &vec {
/// println!("{}", x);
/// }
/// assert_eq!(*vec, [7, 1, 2, 3]);
/// ```
pub struct Vec<T, const N: usize> {
// NOTE order is important for optimizations. the `len` first layout lets the compiler optimize
// `new` to: reserve stack space and zero the first word. With the fields in the reverse order
// the compiler optimizes `new` to `memclr`-ing the *entire* stack space, including the `buffer`
// field which should be left uninitialized. Optimizations were last checked with Rust 1.60
len: usize,
buffer: [MaybeUninit<T>; N],
}
impl<T, const N: usize> Vec<T, N> {
const ELEM: MaybeUninit<T> = MaybeUninit::uninit();
const INIT: [MaybeUninit<T>; N] = [Self::ELEM; N]; // important for optimization of `new`
/// Constructs a new, empty vector with a fixed capacity of `N`
///
/// # Examples
///
/// ```
/// use heapless::Vec;
///
/// // allocate the vector on the stack
/// let mut x: Vec<u8, 16> = Vec::new();
///
/// // allocate the vector in a static variable
/// static mut X: Vec<u8, 16> = Vec::new();
/// ```
/// `Vec` `const` constructor; wrap the returned value in [`Vec`].
pub const fn new() -> Self {
Self {
len: 0,
buffer: Self::INIT,
}
}
/// Constructs a new vector with a fixed capacity of `N` and fills it
/// with the provided slice.
///
/// This is equivalent to the following code:
///
/// ```
/// use heapless::Vec;
///
/// let mut v: Vec<u8, 16> = Vec::new();
/// v.extend_from_slice(&[1, 2, 3]).unwrap();
/// ```
#[inline]
pub fn from_slice(other: &[T]) -> Result<Self, ()>
where
T: Clone,
{
let mut v = Vec::new();
v.extend_from_slice(other)?;
Ok(v)
}
/// Clones a vec into a new vec
pub(crate) fn clone(&self) -> Self
where
T: Clone,
{
let mut new = Self::new();
// avoid `extend_from_slice` as that introduces a runtime check / panicking branch
for elem in self {
unsafe {
new.push_unchecked(elem.clone());
}
}
new
}
/// Returns a raw pointer to the vector’s buffer.
pub fn as_ptr(&self) -> *const T {
self.buffer.as_ptr() as *const T
}
/// Returns a raw pointer to the vector’s buffer, which may be mutated through.
pub fn as_mut_ptr(&mut self) -> *mut T {
self.buffer.as_mut_ptr() as *mut T
}
/// Extracts a slice containing the entire vector.
///
/// Equivalent to `&s[..]`.
///
/// # Examples
///
/// ```
/// use heapless::Vec;
/// let buffer: Vec<u8, 5> = Vec::from_slice(&[1, 2, 3, 5, 8]).unwrap();
/// assert_eq!(buffer.as_slice(), &[1, 2, 3, 5, 8]);
/// ```
pub fn as_slice(&self) -> &[T] {
// NOTE(unsafe) avoid bound checks in the slicing operation
// &buffer[..self.len]
unsafe { slice::from_raw_parts(self.buffer.as_ptr() as *const T, self.len) }
}
/// Returns the contents of the vector as an array of length `M` if the length
/// of the vector is exactly `M`, otherwise returns `Err(self)`.
///
/// # Examples
///
/// ```
/// use heapless::Vec;
/// let buffer: Vec<u8, 42> = Vec::from_slice(&[1, 2, 3, 5, 8]).unwrap();
/// let array: [u8; 5] = buffer.into_array().unwrap();
/// assert_eq!(array, [1, 2, 3, 5, 8]);
/// ```
pub fn into_array<const M: usize>(self) -> Result<[T; M], Self> {
if self.len() == M {
// This is how the unstable `MaybeUninit::array_assume_init` method does it
let array = unsafe { (&self.buffer as *const _ as *const [T; M]).read() };
// We don't want `self`'s destructor to be called because that would drop all the
// items in the array
core::mem::forget(self);
Ok(array)
} else {
Err(self)
}
}
/// Extracts a mutable slice containing the entire vector.
///
/// Equivalent to `&mut s[..]`.
///
/// # Examples
///
/// ```
/// use heapless::Vec;
/// let mut buffer: Vec<u8, 5> = Vec::from_slice(&[1, 2, 3, 5, 8]).unwrap();
/// buffer[0] = 9;
/// assert_eq!(buffer.as_slice(), &[9, 2, 3, 5, 8]);
/// ```
pub fn as_mut_slice(&mut self) -> &mut [T] {
// NOTE(unsafe) avoid bound checks in the slicing operation
// &mut buffer[..self.len]
unsafe { slice::from_raw_parts_mut(self.buffer.as_mut_ptr() as *mut T, self.len) }
}
/// Returns the maximum number of elements the vector can hold.
pub const fn capacity(&self) -> usize {
N
}
/// Clears the vector, removing all values.
pub fn clear(&mut self) {
self.truncate(0);
}
/// Extends the vec from an iterator.
///
/// # Panic
///
/// Panics if the vec cannot hold all elements of the iterator.
pub fn extend<I>(&mut self, iter: I)
where
I: IntoIterator<Item = T>,
{
for elem in iter {
self.push(elem).ok().unwrap()
}
}
/// Clones and appends all elements in a slice to the `Vec`.
///
/// Iterates over the slice `other`, clones each element, and then appends
/// it to this `Vec`. The `other` vector is traversed in-order.
///
/// # Examples
///
/// ```
/// use heapless::Vec;
///
/// let mut vec = Vec::<u8, 8>::new();
/// vec.push(1).unwrap();
/// vec.extend_from_slice(&[2, 3, 4]).unwrap();
/// assert_eq!(*vec, [1, 2, 3, 4]);
/// ```
pub fn extend_from_slice(&mut self, other: &[T]) -> Result<(), ()>
where
T: Clone,
{
if self.len + other.len() > self.capacity() {
// won't fit in the `Vec`; don't modify anything and return an error
Err(())
} else {
for elem in other {
unsafe {
self.push_unchecked(elem.clone());
}
}
Ok(())
}
}
/// Removes the last element from a vector and returns it, or `None` if it's empty
pub fn pop(&mut self) -> Option<T> {
if self.len != 0 {
Some(unsafe { self.pop_unchecked() })
} else {
None
}
}
/// Appends an `item` to the back of the collection
///
/// Returns back the `item` if the vector is full
pub fn push(&mut self, item: T) -> Result<(), T> {
if self.len < self.capacity() {
unsafe { self.push_unchecked(item) }
Ok(())
} else {
Err(item)
}
}
/// Removes the last element from a vector and returns it
///
/// # Safety
///
/// This assumes the vec to have at least one element.
pub unsafe fn pop_unchecked(&mut self) -> T {
debug_assert!(!self.is_empty());
self.len -= 1;
(self.buffer.get_unchecked_mut(self.len).as_ptr() as *const T).read()
}
/// Appends an `item` to the back of the collection
///
/// # Safety
///
/// This assumes the vec is not full.
pub unsafe fn push_unchecked(&mut self, item: T) {
// NOTE(ptr::write) the memory slot that we are about to write to is uninitialized. We
// use `ptr::write` to avoid running `T`'s destructor on the uninitialized memory
debug_assert!(!self.is_full());
*self.buffer.get_unchecked_mut(self.len) = MaybeUninit::new(item);
self.len += 1;
}
/// Shortens the vector, keeping the first `len` elements and dropping the rest.
pub fn truncate(&mut self, len: usize) {
// This is safe because:
//
// * the slice passed to `drop_in_place` is valid; the `len > self.len`
// case avoids creating an invalid slice, and
// * the `len` of the vector is shrunk before calling `drop_in_place`,
// such that no value will be dropped twice in case `drop_in_place`
// were to panic once (if it panics twice, the program aborts).
unsafe {
// Note: It's intentional that this is `>` and not `>=`.
// Changing it to `>=` has negative performance
// implications in some cases. See rust-lang/rust#78884 for more.
if len > self.len {
return;
}
let remaining_len = self.len - len;
let s = ptr::slice_from_raw_parts_mut(self.as_mut_ptr().add(len), remaining_len);
self.len = len;
ptr::drop_in_place(s);
}
}
/// Resizes the Vec in-place so that len is equal to new_len.
///
/// If new_len is greater than len, the Vec is extended by the
/// difference, with each additional slot filled with value. If
/// new_len is less than len, the Vec is simply truncated.
///
/// See also [`resize_default`](Self::resize_default).
pub fn resize(&mut self, new_len: usize, value: T) -> Result<(), ()>
where
T: Clone,
{
if new_len > self.capacity() {
return Err(());
}
if new_len > self.len {
while self.len < new_len {
self.push(value.clone()).ok();
}
} else {
self.truncate(new_len);
}
Ok(())
}
/// Resizes the `Vec` in-place so that `len` is equal to `new_len`.
///
/// If `new_len` is greater than `len`, the `Vec` is extended by the
/// difference, with each additional slot filled with `Default::default()`.
/// If `new_len` is less than `len`, the `Vec` is simply truncated.
///
/// See also [`resize`](Self::resize).
pub fn resize_default(&mut self, new_len: usize) -> Result<(), ()>
where
T: Clone + Default,
{
self.resize(new_len, T::default())
}
/// Forces the length of the vector to `new_len`.
///
/// This is a low-level operation that maintains none of the normal
/// invariants of the type. Normally changing the length of a vector
/// is done using one of the safe operations instead, such as
/// [`truncate`], [`resize`], [`extend`], or [`clear`].
///
/// [`truncate`]: Self::truncate
/// [`resize`]: Self::resize
/// [`extend`]: core::iter::Extend
/// [`clear`]: Self::clear
///
/// # Safety
///
/// - `new_len` must be less than or equal to [`capacity()`].
/// - The elements at `old_len..new_len` must be initialized.
///
/// [`capacity()`]: Self::capacity
///
/// # Examples
///
/// This method can be useful for situations in which the vector
/// is serving as a buffer for other code, particularly over FFI:
///
/// ```no_run
/// # #![allow(dead_code)]
/// use heapless::Vec;
///
/// # // This is just a minimal skeleton for the doc example;
/// # // don't use this as a starting point for a real library.
/// # pub struct StreamWrapper { strm: *mut core::ffi::c_void }
/// # const Z_OK: i32 = 0;
/// # extern "C" {
/// # fn deflateGetDictionary(
/// # strm: *mut core::ffi::c_void,
/// # dictionary: *mut u8,
/// # dictLength: *mut usize,
/// # ) -> i32;
/// # }
/// # impl StreamWrapper {
/// pub fn get_dictionary(&self) -> Option<Vec<u8, 32768>> {
/// // Per the FFI method's docs, "32768 bytes is always enough".
/// let mut dict = Vec::new();
/// let mut dict_length = 0;
/// // SAFETY: When `deflateGetDictionary` returns `Z_OK`, it holds that:
/// // 1. `dict_length` elements were initialized.
/// // 2. `dict_length` <= the capacity (32_768)
/// // which makes `set_len` safe to call.
/// unsafe {
/// // Make the FFI call...
/// let r = deflateGetDictionary(self.strm, dict.as_mut_ptr(), &mut dict_length);
/// if r == Z_OK {
/// // ...and update the length to what was initialized.
/// dict.set_len(dict_length);
/// Some(dict)
/// } else {
/// None
/// }
/// }
/// }
/// # }
/// ```
///
/// While the following example is sound, there is a memory leak since
/// the inner vectors were not freed prior to the `set_len` call:
///
/// ```
/// use core::iter::FromIterator;
/// use heapless::Vec;
///
/// let mut vec = Vec::<Vec<u8, 3>, 3>::from_iter(
/// [
/// Vec::from_iter([1, 0, 0].iter().cloned()),
/// Vec::from_iter([0, 1, 0].iter().cloned()),
/// Vec::from_iter([0, 0, 1].iter().cloned()),
/// ]
/// .iter()
/// .cloned()
/// );
/// // SAFETY:
/// // 1. `old_len..0` is empty so no elements need to be initialized.
/// // 2. `0 <= capacity` always holds whatever `capacity` is.
/// unsafe {
/// vec.set_len(0);
/// }
/// ```
///
/// Normally, here, one would use [`clear`] instead to correctly drop
/// the contents and thus not leak memory.
pub unsafe fn set_len(&mut self, new_len: usize) {
debug_assert!(new_len <= self.capacity());
self.len = new_len
}
/// Removes an element from the vector and returns it.
///
/// The removed element is replaced by the last element of the vector.
///
/// This does not preserve ordering, but is O(1).
///
/// # Panics
///
/// Panics if `index` is out of bounds.
///
/// # Examples
///
/// ```
/// use heapless::Vec;
///// use heapless::consts::*;
///
/// let mut v: Vec<_, 8> = Vec::new();
/// v.push("foo").unwrap();
/// v.push("bar").unwrap();
/// v.push("baz").unwrap();
/// v.push("qux").unwrap();
///
/// assert_eq!(v.swap_remove(1), "bar");
/// assert_eq!(&*v, ["foo", "qux", "baz"]);
///
/// assert_eq!(v.swap_remove(0), "foo");
/// assert_eq!(&*v, ["baz", "qux"]);
/// ```
pub fn swap_remove(&mut self, index: usize) -> T {
assert!(index < self.len);
unsafe { self.swap_remove_unchecked(index) }
}
/// Removes an element from the vector and returns it.
///
/// The removed element is replaced by the last element of the vector.
///
/// This does not preserve ordering, but is O(1).
///
/// # Safety
///
/// Assumes `index` within bounds.
///
/// # Examples
///
/// ```
/// use heapless::Vec;
///
/// let mut v: Vec<_, 8> = Vec::new();
/// v.push("foo").unwrap();
/// v.push("bar").unwrap();
/// v.push("baz").unwrap();
/// v.push("qux").unwrap();
///
/// assert_eq!(unsafe { v.swap_remove_unchecked(1) }, "bar");
/// assert_eq!(&*v, ["foo", "qux", "baz"]);
///
/// assert_eq!(unsafe { v.swap_remove_unchecked(0) }, "foo");
/// assert_eq!(&*v, ["baz", "qux"]);
/// ```
pub unsafe fn swap_remove_unchecked(&mut self, index: usize) -> T {
let length = self.len();
debug_assert!(index < length);
let value = ptr::read(self.as_ptr().add(index));
let base_ptr = self.as_mut_ptr();
ptr::copy(base_ptr.add(length - 1), base_ptr.add(index), 1);
self.len -= 1;
value
}
/// Returns true if the vec is full
#[inline]
pub fn is_full(&self) -> bool {
self.len == self.capacity()
}
/// Returns true if the vec is empty
#[inline]
pub fn is_empty(&self) -> bool {
self.len == 0
}
/// Returns `true` if `needle` is a prefix of the Vec.
///
/// Always returns `true` if `needle` is an empty slice.
///
/// # Examples
///
/// ```
/// use heapless::Vec;
///
/// let v: Vec<_, 8> = Vec::from_slice(b"abc").unwrap();
/// assert_eq!(v.starts_with(b""), true);
/// assert_eq!(v.starts_with(b"ab"), true);
/// assert_eq!(v.starts_with(b"bc"), false);
/// ```
#[inline]
pub fn starts_with(&self, needle: &[T]) -> bool
where
T: PartialEq,
{
let n = needle.len();
self.len >= n && needle == &self[..n]
}
/// Returns `true` if `needle` is a suffix of the Vec.
///
/// Always returns `true` if `needle` is an empty slice.
///
/// # Examples
///
/// ```
/// use heapless::Vec;
///
/// let v: Vec<_, 8> = Vec::from_slice(b"abc").unwrap();
/// assert_eq!(v.ends_with(b""), true);
/// assert_eq!(v.ends_with(b"ab"), false);
/// assert_eq!(v.ends_with(b"bc"), true);
/// ```
#[inline]
pub fn ends_with(&self, needle: &[T]) -> bool
where
T: PartialEq,
{
let (v, n) = (self.len(), needle.len());
v >= n && needle == &self[v - n..]
}
/// Inserts an element at position `index` within the vector, shifting all
/// elements after it to the right.
///
/// Returns back the `element` if the vector is full.
///
/// # Panics
///
/// Panics if `index > len`.
///
/// # Examples
///
/// ```
/// use heapless::Vec;
///
/// let mut vec: Vec<_, 8> = Vec::from_slice(&[1, 2, 3]).unwrap();
/// vec.insert(1, 4);
/// assert_eq!(vec, [1, 4, 2, 3]);
/// vec.insert(4, 5);
/// assert_eq!(vec, [1, 4, 2, 3, 5]);
/// ```
pub fn insert(&mut self, index: usize, element: T) -> Result<(), T> {
let len = self.len();
if index > len {
panic!(
"insertion index (is {}) should be <= len (is {})",
index, len
);
}
// check there's space for the new element
if self.is_full() {
return Err(element);
}
unsafe {
// infallible
// The spot to put the new value
{
let p = self.as_mut_ptr().add(index);
// Shift everything over to make space. (Duplicating the
// `index`th element into two consecutive places.)
ptr::copy(p, p.offset(1), len - index);
// Write it in, overwriting the first copy of the `index`th
// element.
ptr::write(p, element);
}
self.set_len(len + 1);
}
Ok(())
}
/// Removes and returns the element at position `index` within the vector,
/// shifting all elements after it to the left.
///
/// Note: Because this shifts over the remaining elements, it has a
/// worst-case performance of *O*(*n*). If you don't need the order of
/// elements to be preserved, use [`swap_remove`] instead. If you'd like to
/// remove elements from the beginning of the `Vec`, consider using
/// [`Deque::pop_front`] instead.
///
/// [`swap_remove`]: Vec::swap_remove
/// [`Deque::pop_front`]: crate::Deque::pop_front
///
/// # Panics
///
/// Panics if `index` is out of bounds.
///
/// # Examples
///
/// ```
/// use heapless::Vec;
///
/// let mut v: Vec<_, 8> = Vec::from_slice(&[1, 2, 3]).unwrap();
/// assert_eq!(v.remove(1), 2);
/// assert_eq!(v, [1, 3]);
/// ```
pub fn remove(&mut self, index: usize) -> T {
let len = self.len();
if index >= len {
panic!("removal index (is {}) should be < len (is {})", index, len);
}
unsafe {
// infallible
let ret;
{
// the place we are taking from.
let ptr = self.as_mut_ptr().add(index);
// copy it out, unsafely having a copy of the value on
// the stack and in the vector at the same time.
ret = ptr::read(ptr);
// Shift everything down to fill in that spot.
ptr::copy(ptr.offset(1), ptr, len - index - 1);
}
self.set_len(len - 1);
ret
}
}
/// Retains only the elements specified by the predicate.
///
/// In other words, remove all elements `e` for which `f(&e)` returns `false`.
/// This method operates in place, visiting each element exactly once in the
/// original order, and preserves the order of the retained elements.
///
/// # Examples
///
/// ```
/// use heapless::Vec;
///
/// let mut vec: Vec<_, 8> = Vec::from_slice(&[1, 2, 3, 4]).unwrap();
/// vec.retain(|&x| x % 2 == 0);
/// assert_eq!(vec, [2, 4]);
/// ```
///
/// Because the elements are visited exactly once in the original order,
/// external state may be used to decide which elements to keep.
///
/// ```
/// use heapless::Vec;
///
/// let mut vec: Vec<_, 8> = Vec::from_slice(&[1, 2, 3, 4, 5]).unwrap();
/// let keep = [false, true, true, false, true];
/// let mut iter = keep.iter();
/// vec.retain(|_| *iter.next().unwrap());
/// assert_eq!(vec, [2, 3, 5]);
/// ```
pub fn retain<F>(&mut self, mut f: F)
where
F: FnMut(&T) -> bool,
{
self.retain_mut(|elem| f(elem));
}
/// Retains only the elements specified by the predicate, passing a mutable reference to it.
///
/// In other words, remove all elements `e` such that `f(&mut e)` returns `false`.
/// This method operates in place, visiting each element exactly once in the
/// original order, and preserves the order of the retained elements.
///
/// # Examples
///
/// ```
/// use heapless::Vec;
///
/// let mut vec: Vec<_, 8> = Vec::from_slice(&[1, 2, 3, 4]).unwrap();
/// vec.retain_mut(|x| if *x <= 3 {
/// *x += 1;
/// true
/// } else {
/// false
/// });
/// assert_eq!(vec, [2, 3, 4]);
/// ```
pub fn retain_mut<F>(&mut self, mut f: F)
where
F: FnMut(&mut T) -> bool,
{
let original_len = self.len();
// Avoid double drop if the drop guard is not executed,
// since we may make some holes during the process.
unsafe { self.set_len(0) };
// Vec: [Kept, Kept, Hole, Hole, Hole, Hole, Unchecked, Unchecked]
// |<- processed len ->| ^- next to check
// |<- deleted cnt ->|
// |<- original_len ->|
// Kept: Elements which predicate returns true on.
// Hole: Moved or dropped element slot.
// Unchecked: Unchecked valid elements.
//
// This drop guard will be invoked when predicate or `drop` of element panicked.
// It shifts unchecked elements to cover holes and `set_len` to the correct length.
// In cases when predicate and `drop` never panick, it will be optimized out.
struct BackshiftOnDrop<'a, T, const N: usize> {
v: &'a mut Vec<T, N>,
processed_len: usize,
deleted_cnt: usize,
original_len: usize,
}
impl<T, const N: usize> Drop for BackshiftOnDrop<'_, T, N> {
fn drop(&mut self) {
if self.deleted_cnt > 0 {
// SAFETY: Trailing unchecked items must be valid since we never touch them.
unsafe {
ptr::copy(
self.v.as_ptr().add(self.processed_len),
self.v
.as_mut_ptr()
.add(self.processed_len - self.deleted_cnt),
self.original_len - self.processed_len,
);
}
}
// SAFETY: After filling holes, all items are in contiguous memory.
unsafe {
self.v.set_len(self.original_len - self.deleted_cnt);
}
}
}
let mut g = BackshiftOnDrop {
v: self,
processed_len: 0,
deleted_cnt: 0,
original_len,
};
fn process_loop<F, T, const N: usize, const DELETED: bool>(
original_len: usize,
f: &mut F,
g: &mut BackshiftOnDrop<'_, T, N>,
) where
F: FnMut(&mut T) -> bool,
{
while g.processed_len != original_len {
let p = g.v.as_mut_ptr();
// SAFETY: Unchecked element must be valid.
let cur = unsafe { &mut *p.add(g.processed_len) };
if !f(cur) {
// Advance early to avoid double drop if `drop_in_place` panicked.
g.processed_len += 1;
g.deleted_cnt += 1;
// SAFETY: We never touch this element again after dropped.
unsafe { ptr::drop_in_place(cur) };
// We already advanced the counter.
if DELETED {
continue;
} else {
break;
}
}
if DELETED {
// SAFETY: `deleted_cnt` > 0, so the hole slot must not overlap with current element.
// We use copy for move, and never touch this element again.
unsafe {
let hole_slot = p.add(g.processed_len - g.deleted_cnt);
ptr::copy_nonoverlapping(cur, hole_slot, 1);
}
}
g.processed_len += 1;
}
}
// Stage 1: Nothing was deleted.
process_loop::<F, T, N, false>(original_len, &mut f, &mut g);
// Stage 2: Some elements were deleted.
process_loop::<F, T, N, true>(original_len, &mut f, &mut g);
// All item are processed. This can be optimized to `set_len` by LLVM.
drop(g);
}
}
// Trait implementations
impl<T, const N: usize> Default for Vec<T, N> {
fn default() -> Self {
Self::new()
}
}
impl<T, const N: usize> fmt::Debug for Vec<T, N>
where
T: fmt::Debug,
{
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
<[T] as fmt::Debug>::fmt(self, f)
}
}
impl<const N: usize> fmt::Write for Vec<u8, N> {
fn write_str(&mut self, s: &str) -> fmt::Result {
match self.extend_from_slice(s.as_bytes()) {
Ok(()) => Ok(()),
Err(_) => Err(fmt::Error),
}
}
}
impl<T, const N: usize> Drop for Vec<T, N> {
fn drop(&mut self) {
// We drop each element used in the vector by turning into a &mut[T]
unsafe {
ptr::drop_in_place(self.as_mut_slice());
}
}
}
impl<'a, T: Clone, const N: usize> TryFrom<&'a [T]> for Vec<T, N> {
type Error = ();
fn try_from(slice: &'a [T]) -> Result<Self, Self::Error> {
Vec::from_slice(slice)
}
}
impl<T, const N: usize> Extend<T> for Vec<T, N> {
fn extend<I>(&mut self, iter: I)
where
I: IntoIterator<Item = T>,
{
self.extend(iter)
}
}
impl<'a, T, const N: usize> Extend<&'a T> for Vec<T, N>
where
T: 'a + Copy,
{
fn extend<I>(&mut self, iter: I)
where
I: IntoIterator<Item = &'a T>,
{
self.extend(iter.into_iter().cloned())
}
}
impl<T, const N: usize> hash::Hash for Vec<T, N>
where
T: core::hash::Hash,
{
fn hash<H: hash::Hasher>(&self, state: &mut H) {
<[T] as hash::Hash>::hash(self, state)
}
}
impl<'a, T, const N: usize> IntoIterator for &'a Vec<T, N> {
type Item = &'a T;
type IntoIter = slice::Iter<'a, T>;
fn into_iter(self) -> Self::IntoIter {
self.iter()
}
}
impl<'a, T, const N: usize> IntoIterator for &'a mut Vec<T, N> {
type Item = &'a mut T;
type IntoIter = slice::IterMut<'a, T>;
fn into_iter(self) -> Self::IntoIter {
self.iter_mut()
}
}
impl<T, const N: usize> FromIterator<T> for Vec<T, N> {
fn from_iter<I>(iter: I) -> Self
where
I: IntoIterator<Item = T>,
{
let mut vec = Vec::new();
for i in iter {
vec.push(i).ok().expect("Vec::from_iter overflow");
}
vec
}
}
/// An iterator that moves out of an [`Vec`][`Vec`].
///
/// This struct is created by calling the `into_iter` method on [`Vec`][`Vec`].
pub struct IntoIter<T, const N: usize> {
vec: Vec<T, N>,
next: usize,
}
impl<T, const N: usize> Iterator for IntoIter<T, N> {
type Item = T;
fn next(&mut self) -> Option<Self::Item> {
if self.next < self.vec.len() {
let item = unsafe {
(self.vec.buffer.get_unchecked_mut(self.next).as_ptr() as *const T).read()
};
self.next += 1;
Some(item)
} else {
None
}
}
}
impl<T, const N: usize> Clone for IntoIter<T, N>
where
T: Clone,
{
fn clone(&self) -> Self {
let mut vec = Vec::new();
if self.next < self.vec.len() {
let s = unsafe {
slice::from_raw_parts(
(self.vec.buffer.as_ptr() as *const T).add(self.next),
self.vec.len() - self.next,
)
};
vec.extend_from_slice(s).ok();
}
Self { vec, next: 0 }
}
}
impl<T, const N: usize> Drop for IntoIter<T, N> {
fn drop(&mut self) {
unsafe {
// Drop all the elements that have not been moved out of vec
ptr::drop_in_place(&mut self.vec.as_mut_slice()[self.next..]);
// Prevent dropping of other elements
self.vec.len = 0;
}
}
}
impl<T, const N: usize> IntoIterator for Vec<T, N> {
type Item = T;
type IntoIter = IntoIter<T, N>;
fn into_iter(self) -> Self::IntoIter {
IntoIter { vec: self, next: 0 }
}
}
impl<A, B, const N1: usize, const N2: usize> PartialEq<Vec<B, N2>> for Vec<A, N1>
where
A: PartialEq<B>,
{
fn eq(&self, other: &Vec<B, N2>) -> bool {
<[A]>::eq(self, &**other)
}
}
// Vec<A, N> == [B]
impl<A, B, const N: usize> PartialEq<[B]> for Vec<A, N>
where
A: PartialEq<B>,
{
fn eq(&self, other: &[B]) -> bool {
<[A]>::eq(self, &other[..])
}
}
// [B] == Vec<A, N>
impl<A, B, const N: usize> PartialEq<Vec<A, N>> for [B]
where
A: PartialEq<B>,
{
fn eq(&self, other: &Vec<A, N>) -> bool {
<[A]>::eq(other, &self[..])
}
}
// Vec<A, N> == &[B]
impl<A, B, const N: usize> PartialEq<&[B]> for Vec<A, N>
where
A: PartialEq<B>,
{
fn eq(&self, other: &&[B]) -> bool {
<[A]>::eq(self, &other[..])
}
}
// &[B] == Vec<A, N>
impl<A, B, const N: usize> PartialEq<Vec<A, N>> for &[B]
where
A: PartialEq<B>,
{
fn eq(&self, other: &Vec<A, N>) -> bool {
<[A]>::eq(other, &self[..])
}
}
// Vec<A, N> == &mut [B]
impl<A, B, const N: usize> PartialEq<&mut [B]> for Vec<A, N>
where
A: PartialEq<B>,
{
fn eq(&self, other: &&mut [B]) -> bool {
<[A]>::eq(self, &other[..])
}
}
// &mut [B] == Vec<A, N>
impl<A, B, const N: usize> PartialEq<Vec<A, N>> for &mut [B]
where
A: PartialEq<B>,
{
fn eq(&self, other: &Vec<A, N>) -> bool {
<[A]>::eq(other, &self[..])
}
}
// Vec<A, N> == [B; M]
// Equality does not require equal capacity
impl<A, B, const N: usize, const M: usize> PartialEq<[B; M]> for Vec<A, N>
where
A: PartialEq<B>,
{
fn eq(&self, other: &[B; M]) -> bool {
<[A]>::eq(self, &other[..])
}
}
// [B; M] == Vec<A, N>
// Equality does not require equal capacity
impl<A, B, const N: usize, const M: usize> PartialEq<Vec<A, N>> for [B; M]
where
A: PartialEq<B>,
{
fn eq(&self, other: &Vec<A, N>) -> bool {
<[A]>::eq(other, &self[..])
}
}
// Vec<A, N> == &[B; M]
// Equality does not require equal capacity
impl<A, B, const N: usize, const M: usize> PartialEq<&[B; M]> for Vec<A, N>
where
A: PartialEq<B>,
{
fn eq(&self, other: &&[B; M]) -> bool {
<[A]>::eq(self, &other[..])
}
}
// &[B; M] == Vec<A, N>
// Equality does not require equal capacity
impl<A, B, const N: usize, const M: usize> PartialEq<Vec<A, N>> for &[B; M]
where
A: PartialEq<B>,
{
fn eq(&self, other: &Vec<A, N>) -> bool {
<[A]>::eq(other, &self[..])
}
}
// Implements Eq if underlying data is Eq
impl<T, const N: usize> Eq for Vec<T, N> where T: Eq {}
impl<T, const N1: usize, const N2: usize> PartialOrd<Vec<T, N2>> for Vec<T, N1>
where
T: PartialOrd,
{
fn partial_cmp(&self, other: &Vec<T, N2>) -> Option<Ordering> {
PartialOrd::partial_cmp(&**self, &**other)
}
}
impl<T, const N: usize> Ord for Vec<T, N>
where
T: Ord,
{
#[inline]
fn cmp(&self, other: &Self) -> Ordering {
Ord::cmp(&**self, &**other)
}
}
impl<T, const N: usize> ops::Deref for Vec<T, N> {
type Target = [T];
fn deref(&self) -> &[T] {
self.as_slice()
}
}
impl<T, const N: usize> ops::DerefMut for Vec<T, N> {
fn deref_mut(&mut self) -> &mut [T] {
self.as_mut_slice()
}
}
impl<T, const N: usize> AsRef<Vec<T, N>> for Vec<T, N> {
#[inline]
fn as_ref(&self) -> &Self {
self
}
}
impl<T, const N: usize> AsMut<Vec<T, N>> for Vec<T, N> {
#[inline]
fn as_mut(&mut self) -> &mut Self {
self
}
}
impl<T, const N: usize> AsRef<[T]> for Vec<T, N> {
#[inline]
fn as_ref(&self) -> &[T] {
self
}
}
impl<T, const N: usize> AsMut<[T]> for Vec<T, N> {
#[inline]
fn as_mut(&mut self) -> &mut [T] {
self
}
}
impl<T, const N: usize> Clone for Vec<T, N>
where
T: Clone,
{
fn clone(&self) -> Self {
self.clone()
}
}
#[cfg(test)]
mod tests {
use crate::Vec;
use core::fmt::Write;
#[test]
fn static_new() {
static mut _V: Vec<i32, 4> = Vec::new();
}
#[test]
fn stack_new() {
let mut _v: Vec<i32, 4> = Vec::new();
}
#[test]
fn is_full_empty() {
let mut v: Vec<i32, 4> = Vec::new();
assert!(v.is_empty());
assert!(!v.is_full());
v.push(1).unwrap();
assert!(!v.is_empty());
assert!(!v.is_full());
v.push(1).unwrap();
assert!(!v.is_empty());
assert!(!v.is_full());
v.push(1).unwrap();
assert!(!v.is_empty());
assert!(!v.is_full());
v.push(1).unwrap();
assert!(!v.is_empty());
assert!(v.is_full());
}
#[test]
fn drop() {
droppable!();
{
let mut v: Vec<Droppable, 2> = Vec::new();
v.push(Droppable::new()).ok().unwrap();
v.push(Droppable::new()).ok().unwrap();
v.pop().unwrap();
}
assert_eq!(Droppable::count(), 0);
{
let mut v: Vec<Droppable, 2> = Vec::new();
v.push(Droppable::new()).ok().unwrap();
v.push(Droppable::new()).ok().unwrap();
}
assert_eq!(Droppable::count(), 0);
}
#[test]
fn eq() {
let mut xs: Vec<i32, 4> = Vec::new();
let mut ys: Vec<i32, 8> = Vec::new();
assert_eq!(xs, ys);
xs.push(1).unwrap();
ys.push(1).unwrap();
assert_eq!(xs, ys);
}
#[test]
fn cmp() {
let mut xs: Vec<i32, 4> = Vec::new();
let mut ys: Vec<i32, 4> = Vec::new();
assert_eq!(xs, ys);
xs.push(1).unwrap();
ys.push(2).unwrap();
assert!(xs < ys);
}
#[test]
fn cmp_heterogenous_size() {
let mut xs: Vec<i32, 4> = Vec::new();
let mut ys: Vec<i32, 8> = Vec::new();
assert_eq!(xs, ys);
xs.push(1).unwrap();
ys.push(2).unwrap();
assert!(xs < ys);
}
#[test]
fn cmp_with_arrays_and_slices() {
let mut xs: Vec<i32, 12> = Vec::new();
xs.push(1).unwrap();
let array = [1];
assert_eq!(xs, array);
assert_eq!(array, xs);
assert_eq!(xs, array.as_slice());
assert_eq!(array.as_slice(), xs);
assert_eq!(xs, &array);
assert_eq!(&array, xs);
let longer_array = [1; 20];
assert_ne!(xs, longer_array);
assert_ne!(longer_array, xs);
}
#[test]
fn full() {
let mut v: Vec<i32, 4> = Vec::new();
v.push(0).unwrap();
v.push(1).unwrap();
v.push(2).unwrap();
v.push(3).unwrap();
assert!(v.push(4).is_err());
}
#[test]
fn iter() {
let mut v: Vec<i32, 4> = Vec::new();
v.push(0).unwrap();
v.push(1).unwrap();
v.push(2).unwrap();
v.push(3).unwrap();
let mut items = v.iter();
assert_eq!(items.next(), Some(&0));
assert_eq!(items.next(), Some(&1));
assert_eq!(items.next(), Some(&2));
assert_eq!(items.next(), Some(&3));
assert_eq!(items.next(), None);
}
#[test]
fn iter_mut() {
let mut v: Vec<i32, 4> = Vec::new();
v.push(0).unwrap();
v.push(1).unwrap();
v.push(2).unwrap();
v.push(3).unwrap();
let mut items = v.iter_mut();
assert_eq!(items.next(), Some(&mut 0));
assert_eq!(items.next(), Some(&mut 1));
assert_eq!(items.next(), Some(&mut 2));
assert_eq!(items.next(), Some(&mut 3));
assert_eq!(items.next(), None);
}
#[test]
fn collect_from_iter() {
let slice = &[1, 2, 3];
let vec: Vec<i32, 4> = slice.iter().cloned().collect();
assert_eq!(&vec, slice);
}
#[test]
#[should_panic]
fn collect_from_iter_overfull() {
let slice = &[1, 2, 3];
let _vec = slice.iter().cloned().collect::<Vec<_, 2>>();
}
#[test]
fn iter_move() {
let mut v: Vec<i32, 4> = Vec::new();
v.push(0).unwrap();
v.push(1).unwrap();
v.push(2).unwrap();
v.push(3).unwrap();
let mut items = v.into_iter();
assert_eq!(items.next(), Some(0));
assert_eq!(items.next(), Some(1));
assert_eq!(items.next(), Some(2));
assert_eq!(items.next(), Some(3));
assert_eq!(items.next(), None);
}
#[test]
fn iter_move_drop() {
droppable!();
{
let mut vec: Vec<Droppable, 2> = Vec::new();
vec.push(Droppable::new()).ok().unwrap();
vec.push(Droppable::new()).ok().unwrap();
let mut items = vec.into_iter();
// Move all
let _ = items.next();
let _ = items.next();
}
assert_eq!(Droppable::count(), 0);
{
let mut vec: Vec<Droppable, 2> = Vec::new();
vec.push(Droppable::new()).ok().unwrap();
vec.push(Droppable::new()).ok().unwrap();
let _items = vec.into_iter();
// Move none
}
assert_eq!(Droppable::count(), 0);
{
let mut vec: Vec<Droppable, 2> = Vec::new();
vec.push(Droppable::new()).ok().unwrap();
vec.push(Droppable::new()).ok().unwrap();
let mut items = vec.into_iter();
let _ = items.next(); // Move partly
}
assert_eq!(Droppable::count(), 0);
}
#[test]
fn push_and_pop() {
let mut v: Vec<i32, 4> = Vec::new();
assert_eq!(v.len(), 0);
assert_eq!(v.pop(), None);
assert_eq!(v.len(), 0);
v.push(0).unwrap();
assert_eq!(v.len(), 1);
assert_eq!(v.pop(), Some(0));
assert_eq!(v.len(), 0);
assert_eq!(v.pop(), None);
assert_eq!(v.len(), 0);
}
#[test]
fn resize_size_limit() {
let mut v: Vec<u8, 4> = Vec::new();
v.resize(0, 0).unwrap();
v.resize(4, 0).unwrap();
v.resize(5, 0).err().expect("full");
}
#[test]
fn resize_length_cases() {
let mut v: Vec<u8, 4> = Vec::new();
assert_eq!(v.len(), 0);
// Grow by 1
v.resize(1, 0).unwrap();
assert_eq!(v.len(), 1);
// Grow by 2
v.resize(3, 0).unwrap();
assert_eq!(v.len(), 3);
// Resize to current size
v.resize(3, 0).unwrap();
assert_eq!(v.len(), 3);
// Shrink by 1
v.resize(2, 0).unwrap();
assert_eq!(v.len(), 2);
// Shrink by 2
v.resize(0, 0).unwrap();
assert_eq!(v.len(), 0);
}
#[test]
fn resize_contents() {
let mut v: Vec<u8, 4> = Vec::new();
// New entries take supplied value when growing
v.resize(1, 17).unwrap();
assert_eq!(v[0], 17);
// Old values aren't changed when growing
v.resize(2, 18).unwrap();
assert_eq!(v[0], 17);
assert_eq!(v[1], 18);
// Old values aren't changed when length unchanged
v.resize(2, 0).unwrap();
assert_eq!(v[0], 17);
assert_eq!(v[1], 18);
// Old values aren't changed when shrinking
v.resize(1, 0).unwrap();
assert_eq!(v[0], 17);
}
#[test]
fn resize_default() {
let mut v: Vec<u8, 4> = Vec::new();
// resize_default is implemented using resize, so just check the
// correct value is being written.
v.resize_default(1).unwrap();
assert_eq!(v[0], 0);
}
#[test]
fn write() {
let mut v: Vec<u8, 4> = Vec::new();
write!(v, "{:x}", 1234).unwrap();
assert_eq!(&v[..], b"4d2");
}
#[test]
fn extend_from_slice() {
let mut v: Vec<u8, 4> = Vec::new();
assert_eq!(v.len(), 0);
v.extend_from_slice(&[1, 2]).unwrap();
assert_eq!(v.len(), 2);
assert_eq!(v.as_slice(), &[1, 2]);
v.extend_from_slice(&[3]).unwrap();
assert_eq!(v.len(), 3);
assert_eq!(v.as_slice(), &[1, 2, 3]);
assert!(v.extend_from_slice(&[4, 5]).is_err());
assert_eq!(v.len(), 3);
assert_eq!(v.as_slice(), &[1, 2, 3]);
}
#[test]
fn from_slice() {
// Successful construction
let v: Vec<u8, 4> = Vec::from_slice(&[1, 2, 3]).unwrap();
assert_eq!(v.len(), 3);
assert_eq!(v.as_slice(), &[1, 2, 3]);
// Slice too large
assert!(Vec::<u8, 2>::from_slice(&[1, 2, 3]).is_err());
}
#[test]
fn starts_with() {
let v: Vec<_, 8> = Vec::from_slice(b"ab").unwrap();
assert!(v.starts_with(&[]));
assert!(v.starts_with(b""));
assert!(v.starts_with(b"a"));
assert!(v.starts_with(b"ab"));
assert!(!v.starts_with(b"abc"));
assert!(!v.starts_with(b"ba"));
assert!(!v.starts_with(b"b"));
}
#[test]
fn ends_with() {
let v: Vec<_, 8> = Vec::from_slice(b"ab").unwrap();
assert!(v.ends_with(&[]));
assert!(v.ends_with(b""));
assert!(v.ends_with(b"b"));
assert!(v.ends_with(b"ab"));
assert!(!v.ends_with(b"abc"));
assert!(!v.ends_with(b"ba"));
assert!(!v.ends_with(b"a"));
}
#[test]
fn zero_capacity() {
let mut v: Vec<u8, 0> = Vec::new();
// Validate capacity
assert_eq!(v.capacity(), 0);
// Make sure there is no capacity
assert!(v.push(1).is_err());
// Validate length
assert_eq!(v.len(), 0);
// Validate pop
assert_eq!(v.pop(), None);
// Validate slice
assert_eq!(v.as_slice(), &[]);
// Validate empty
assert!(v.is_empty());
// Validate full
assert!(v.is_full());
}
}