From 1982d4044580dd8051daea6ff8272284cb872648 Mon Sep 17 00:00:00 2001 From: nitram Date: Thu, 17 Oct 2024 16:13:01 +0200 Subject: [PATCH] Add `ArrayVecCopy` Fixes #32. --- src/arrayvec_copy.rs | 1320 ++++++++++++++++++++++++++++++++++++++++++ src/lib.rs | 6 + 2 files changed, 1326 insertions(+) create mode 100644 src/arrayvec_copy.rs diff --git a/src/arrayvec_copy.rs b/src/arrayvec_copy.rs new file mode 100644 index 0000000..df3fa90 --- /dev/null +++ b/src/arrayvec_copy.rs @@ -0,0 +1,1320 @@ + +use std::cmp; +use std::iter; +use std::mem; +use std::ops::{Bound, Deref, DerefMut, RangeBounds}; +use std::ptr; +use std::slice; + +// extra traits +use std::borrow::{Borrow, BorrowMut}; +use std::hash::{Hash, Hasher}; +use std::fmt; + +#[cfg(feature="std")] +use std::io; + +use std::mem::MaybeUninit; + +#[cfg(feature="serde")] +use serde::{Serialize, Deserialize, Serializer, Deserializer}; + +use crate::LenUint; +use crate::errors::CapacityError; +use crate::arrayvec_impl::ArrayVecImpl; +use crate::utils::MakeMaybeUninit; + +/// A vector with a fixed capacity which implements `Copy` and its elemenents are constrained to also be `Copy`. +/// +/// The `ArrayVecCopy` is a vector backed by a fixed size array. It keeps track of +/// the number of initialized elements. The `ArrayVecCopy` is parameterized +/// by `T` for the element type and `CAP` for the maximum capacity. +/// +/// `CAP` is of type `usize` but is range limited to `u32::MAX`; attempting to create larger +/// arrayvecs with larger capacity will panic. +/// +/// The vector is a contiguous value (storing the elements inline) that you can store directly on +/// the stack if needed. +/// +/// It offers a simple API but also dereferences to a slice, so that the full slice API is +/// available. The ArrayVecCopy can be converted into a by value iterator. +#[repr(C)] +pub struct ArrayVecCopy { + len: LenUint, + // the `len` first elements of the array are initialized + xs: [MaybeUninit; CAP], +} + +macro_rules! panic_oob { + ($method_name:expr, $index:expr, $len:expr) => { + panic!(concat!("ArrayVecCopy::", $method_name, ": index {} is out of bounds in vector of length {}"), + $index, $len) + } +} + +impl ArrayVecCopy { + /// Capacity + const CAPACITY: usize = CAP; + + /// Create a new empty `ArrayVecCopy`. + /// + /// The maximum capacity is given by the generic parameter `CAP`. + /// + /// ``` + /// use arrayvec::ArrayVecCopy; + /// + /// let mut array = ArrayVecCopy::<_, 16>::new(); + /// array.push(1); + /// array.push(2); + /// assert_eq!(&array[..], &[1, 2]); + /// assert_eq!(array.capacity(), 16); + /// ``` + #[inline] + #[track_caller] + pub fn new() -> ArrayVecCopy { + assert_capacity_limit!(CAP); + unsafe { + ArrayVecCopy { xs: MaybeUninit::uninit().assume_init(), len: 0 } + } + } + + /// Create a new empty `ArrayVecCopy` (const fn). + /// + /// The maximum capacity is given by the generic parameter `CAP`. + /// + /// ``` + /// use arrayvec::ArrayVecCopy; + /// + /// static ARRAY: ArrayVecCopy = ArrayVecCopy::new_const(); + /// ``` + pub const fn new_const() -> ArrayVecCopy { + assert_capacity_limit_const!(CAP); + ArrayVecCopy { xs: MakeMaybeUninit::ARRAY, len: 0 } + } + + /// Return the number of elements in the `ArrayVecCopy`. + /// + /// ``` + /// use arrayvec::ArrayVecCopy; + /// + /// let mut array = ArrayVecCopy::from([1, 2, 3]); + /// array.pop(); + /// assert_eq!(array.len(), 2); + /// ``` + #[inline(always)] + pub const fn len(&self) -> usize { self.len as usize } + + /// Returns whether the `ArrayVecCopy` is empty. + /// + /// ``` + /// use arrayvec::ArrayVecCopy; + /// + /// let mut array = ArrayVecCopy::from([1]); + /// array.pop(); + /// assert_eq!(array.is_empty(), true); + /// ``` + #[inline] + pub const fn is_empty(&self) -> bool { self.len() == 0 } + + /// Return the capacity of the `ArrayVecCopy`. + /// + /// ``` + /// use arrayvec::ArrayVecCopy; + /// + /// let array = ArrayVecCopy::from([1, 2, 3]); + /// assert_eq!(array.capacity(), 3); + /// ``` + #[inline(always)] + pub const fn capacity(&self) -> usize { CAP } + + /// Return true if the `ArrayVecCopy` is completely filled to its capacity, false otherwise. + /// + /// ``` + /// use arrayvec::ArrayVecCopy; + /// + /// let mut array = ArrayVecCopy::<_, 1>::new(); + /// assert!(!array.is_full()); + /// array.push(1); + /// assert!(array.is_full()); + /// ``` + pub const fn is_full(&self) -> bool { self.len() == self.capacity() } + + /// Returns the capacity left in the `ArrayVecCopy`. + /// + /// ``` + /// use arrayvec::ArrayVecCopy; + /// + /// let mut array = ArrayVecCopy::from([1, 2, 3]); + /// array.pop(); + /// assert_eq!(array.remaining_capacity(), 1); + /// ``` + pub const fn remaining_capacity(&self) -> usize { + self.capacity() - self.len() + } + + /// Push `element` to the end of the vector. + /// + /// ***Panics*** if the vector is already full. + /// + /// ``` + /// use arrayvec::ArrayVecCopy; + /// + /// let mut array = ArrayVecCopy::<_, 2>::new(); + /// + /// array.push(1); + /// array.push(2); + /// + /// assert_eq!(&array[..], &[1, 2]); + /// ``` + #[track_caller] + pub fn push(&mut self, element: T) { + ArrayVecImpl::push(self, element) + } + + /// Push `element` to the end of the vector. + /// + /// Return `Ok` if the push succeeds, or return an error if the vector + /// is already full. + /// + /// ``` + /// use arrayvec::ArrayVecCopy; + /// + /// let mut array = ArrayVecCopy::<_, 2>::new(); + /// + /// let push1 = array.try_push(1); + /// let push2 = array.try_push(2); + /// + /// assert!(push1.is_ok()); + /// assert!(push2.is_ok()); + /// + /// assert_eq!(&array[..], &[1, 2]); + /// + /// let overflow = array.try_push(3); + /// + /// assert!(overflow.is_err()); + /// ``` + pub fn try_push(&mut self, element: T) -> Result<(), CapacityError> { + ArrayVecImpl::try_push(self, element) + } + + /// Push `element` to the end of the vector without checking the capacity. + /// + /// It is up to the caller to ensure the capacity of the vector is + /// sufficiently large. + /// + /// This method uses *debug assertions* to check that the arrayvec is not full. + /// + /// ``` + /// use arrayvec::ArrayVecCopy; + /// + /// let mut array = ArrayVecCopy::<_, 2>::new(); + /// + /// if array.len() + 2 <= array.capacity() { + /// unsafe { + /// array.push_unchecked(1); + /// array.push_unchecked(2); + /// } + /// } + /// + /// assert_eq!(&array[..], &[1, 2]); + /// ``` + pub unsafe fn push_unchecked(&mut self, element: T) { + ArrayVecImpl::push_unchecked(self, element) + } + + /// Shortens the vector, keeping the first `len` elements. + /// + /// If `len` is greater than the vector’s current length this has no + /// effect. + /// + /// ``` + /// use arrayvec::ArrayVecCopy; + /// + /// let mut array = ArrayVecCopy::from([1, 2, 3, 4, 5]); + /// array.truncate(3); + /// assert_eq!(&array[..], &[1, 2, 3]); + /// array.truncate(4); + /// assert_eq!(&array[..], &[1, 2, 3]); + /// ``` + pub fn truncate(&mut self, new_len: usize) { + ArrayVecImpl::truncate(self, new_len) + } + + /// Remove all elements in the vector. + pub fn clear(&mut self) { + ArrayVecImpl::clear(self) + } + + + /// Get pointer to where element at `index` would be + unsafe fn get_unchecked_ptr(&mut self, index: usize) -> *mut T { + self.as_mut_ptr().add(index) + } + + /// Insert `element` at position `index`. + /// + /// Shift up all elements after `index`. + /// + /// It is an error if the index is greater than the length or if the + /// arrayvec is full. + /// + /// ***Panics*** if the array is full or the `index` is out of bounds. See + /// `try_insert` for fallible version. + /// + /// ``` + /// use arrayvec::ArrayVecCopy; + /// + /// let mut array = ArrayVecCopy::<_, 2>::new(); + /// + /// array.insert(0, "x"); + /// array.insert(0, "y"); + /// assert_eq!(&array[..], &["y", "x"]); + /// + /// ``` + #[track_caller] + pub fn insert(&mut self, index: usize, element: T) { + self.try_insert(index, element).unwrap() + } + + /// Insert `element` at position `index`. + /// + /// Shift up all elements after `index`; the `index` must be less than + /// or equal to the length. + /// + /// Returns an error if vector is already at full capacity. + /// + /// ***Panics*** `index` is out of bounds. + /// + /// ``` + /// use arrayvec::ArrayVecCopy; + /// + /// let mut array = ArrayVecCopy::<_, 2>::new(); + /// + /// assert!(array.try_insert(0, "x").is_ok()); + /// assert!(array.try_insert(0, "y").is_ok()); + /// assert!(array.try_insert(0, "z").is_err()); + /// assert_eq!(&array[..], &["y", "x"]); + /// + /// ``` + pub fn try_insert(&mut self, index: usize, element: T) -> Result<(), CapacityError> { + if index > self.len() { + panic_oob!("try_insert", index, self.len()) + } + if self.len() == self.capacity() { + return Err(CapacityError::new(element)); + } + let len = self.len(); + + // follows is just like Vec + unsafe { // infallible + // The spot to put the new value + { + let p: *mut _ = self.get_unchecked_ptr(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(()) + } + + /// Remove the last element in the vector and return it. + /// + /// Return `Some(` *element* `)` if the vector is non-empty, else `None`. + /// + /// ``` + /// use arrayvec::ArrayVecCopy; + /// + /// let mut array = ArrayVecCopy::<_, 2>::new(); + /// + /// array.push(1); + /// + /// assert_eq!(array.pop(), Some(1)); + /// assert_eq!(array.pop(), None); + /// ``` + pub fn pop(&mut self) -> Option { + ArrayVecImpl::pop(self) + } + + /// Remove the element at `index` and swap the last element into its place. + /// + /// This operation is O(1). + /// + /// Return the *element* if the index is in bounds, else panic. + /// + /// ***Panics*** if the `index` is out of bounds. + /// + /// ``` + /// use arrayvec::ArrayVecCopy; + /// + /// let mut array = ArrayVecCopy::from([1, 2, 3]); + /// + /// assert_eq!(array.swap_remove(0), 1); + /// assert_eq!(&array[..], &[3, 2]); + /// + /// assert_eq!(array.swap_remove(1), 2); + /// assert_eq!(&array[..], &[3]); + /// ``` + pub fn swap_remove(&mut self, index: usize) -> T { + self.swap_pop(index) + .unwrap_or_else(|| { + panic_oob!("swap_remove", index, self.len()) + }) + } + + /// Remove the element at `index` and swap the last element into its place. + /// + /// This is a checked version of `.swap_remove`. + /// This operation is O(1). + /// + /// Return `Some(` *element* `)` if the index is in bounds, else `None`. + /// + /// ``` + /// use arrayvec::ArrayVecCopy; + /// + /// let mut array = ArrayVecCopy::from([1, 2, 3]); + /// + /// assert_eq!(array.swap_pop(0), Some(1)); + /// assert_eq!(&array[..], &[3, 2]); + /// + /// assert_eq!(array.swap_pop(10), None); + /// ``` + pub fn swap_pop(&mut self, index: usize) -> Option { + let len = self.len(); + if index >= len { + return None; + } + self.swap(index, len - 1); + self.pop() + } + + /// Remove the element at `index` and shift down the following elements. + /// + /// The `index` must be strictly less than the length of the vector. + /// + /// ***Panics*** if the `index` is out of bounds. + /// + /// ``` + /// use arrayvec::ArrayVecCopy; + /// + /// let mut array = ArrayVecCopy::from([1, 2, 3]); + /// + /// let removed_elt = array.remove(0); + /// assert_eq!(removed_elt, 1); + /// assert_eq!(&array[..], &[2, 3]); + /// ``` + pub fn remove(&mut self, index: usize) -> T { + self.pop_at(index) + .unwrap_or_else(|| { + panic_oob!("remove", index, self.len()) + }) + } + + /// Remove the element at `index` and shift down the following elements. + /// + /// This is a checked version of `.remove(index)`. Returns `None` if there + /// is no element at `index`. Otherwise, return the element inside `Some`. + /// + /// ``` + /// use arrayvec::ArrayVecCopy; + /// + /// let mut array = ArrayVecCopy::from([1, 2, 3]); + /// + /// assert!(array.pop_at(0).is_some()); + /// assert_eq!(&array[..], &[2, 3]); + /// + /// assert!(array.pop_at(2).is_none()); + /// assert!(array.pop_at(10).is_none()); + /// ``` + pub fn pop_at(&mut self, index: usize) -> Option { + if index >= self.len() { + None + } else { + self.drain(index..index + 1).next() + } + } + + /// Retains only the elements specified by the predicate. + /// + /// In other words, remove all elements `e` such that `f(&mut e)` returns false. + /// This method operates in place and preserves the order of the retained + /// elements. + /// + /// ``` + /// use arrayvec::ArrayVecCopy; + /// + /// let mut array = ArrayVecCopy::from([1, 2, 3, 4]); + /// array.retain(|x| *x & 1 != 0 ); + /// assert_eq!(&array[..], &[1, 3]); + /// ``` + pub fn retain(&mut self, mut f: F) + where F: FnMut(&mut T) -> bool + { + // Check the implementation of + // https://doc.rust-lang.org/std/vec/struct.Vec.html#method.retain + // for safety arguments (especially regarding panics in f and when + // dropping elements). Implementation closely mirrored here. + + let original_len = self.len(); + unsafe { self.set_len(0) }; + + struct BackshiftOnDrop<'a, T: Copy, const CAP: usize> { + v: &'a mut ArrayVecCopy, + processed_len: usize, + deleted_cnt: usize, + original_len: usize, + } + + impl Drop for BackshiftOnDrop<'_, T, CAP> { + fn drop(&mut self) { + if self.deleted_cnt > 0 { + 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 + ); + } + } + 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 }; + + #[inline(always)] + fn process_one bool, const CAP: usize, const DELETED: bool>( + f: &mut F, + g: &mut BackshiftOnDrop<'_, T, CAP> + ) -> bool { + let cur = unsafe { g.v.as_mut_ptr().add(g.processed_len) }; + if !f(unsafe { &mut *cur }) { + g.processed_len += 1; + g.deleted_cnt += 1; + return false; + } + if DELETED { + unsafe { + let hole_slot = cur.sub(g.deleted_cnt); + ptr::copy_nonoverlapping(cur, hole_slot, 1); + } + } + g.processed_len += 1; + true + } + + // Stage 1: Nothing was deleted. + while g.processed_len != original_len { + if !process_one::(&mut f, &mut g) { + break; + } + } + + // Stage 2: Some elements were deleted. + while g.processed_len != original_len { + process_one::(&mut f, &mut g); + } + + drop(g); + } + + /// Set the vector’s length without moving out elements + /// + /// This method is `unsafe` because it changes the notion of the + /// number of “valid” elements in the vector. Use with care. + /// + /// This method uses *debug assertions* to check that `length` is + /// not greater than the capacity. + pub unsafe fn set_len(&mut self, length: usize) { + // type invariant that capacity always fits in LenUint + debug_assert!(length <= self.capacity()); + self.len = length as LenUint; + } + + /// Copy all elements from the slice and append to the `ArrayVecCopy`. + /// + /// ``` + /// use arrayvec::ArrayVecCopy; + /// + /// let mut vec: ArrayVecCopy = ArrayVecCopy::new(); + /// vec.push(1); + /// vec.try_extend_from_slice(&[2, 3]).unwrap(); + /// assert_eq!(&vec[..], &[1, 2, 3]); + /// ``` + /// + /// # Errors + /// + /// This method will return an error if the capacity left (see + /// [`remaining_capacity`]) is smaller then the length of the provided + /// slice. + /// + /// [`remaining_capacity`]: #method.remaining_capacity + pub fn try_extend_from_slice(&mut self, other: &[T]) -> Result<(), CapacityError> + where T: Copy, + { + if self.remaining_capacity() < other.len() { + return Err(CapacityError::new(())); + } + + let self_len = self.len(); + let other_len = other.len(); + + unsafe { + let dst = self.get_unchecked_ptr(self_len); + ptr::copy_nonoverlapping(other.as_ptr(), dst, other_len); + self.set_len(self_len + other_len); + } + Ok(()) + } + + /// Create a draining iterator that removes the specified range in the vector + /// and yields the removed items from start to end. The element range is + /// removed even if the iterator is not consumed until the end. + /// + /// Note: It is unspecified how many elements are removed from the vector, + /// if the `Drain` value is leaked. + /// + /// **Panics** if the starting point is greater than the end point or if + /// the end point is greater than the length of the vector. + /// + /// ``` + /// use arrayvec::ArrayVecCopy; + /// + /// let mut v1 = ArrayVecCopy::from([1, 2, 3]); + /// let v2: ArrayVecCopy<_, 3> = v1.drain(0..2).collect(); + /// assert_eq!(&v1[..], &[3]); + /// assert_eq!(&v2[..], &[1, 2]); + /// ``` + pub fn drain(&mut self, range: R) -> Drain + where R: RangeBounds + { + // Memory safety + // + // When the Drain is first created, it shortens the length of + // the source vector to make sure no uninitialized or moved-from elements + // are accessible at all if the Drain's destructor never gets to run. + // + // Drain will ptr::read out the values to remove. + // When finished, remaining tail of the vec is copied back to cover + // the hole, and the vector length is restored to the new length. + // + let len = self.len(); + let start = match range.start_bound() { + Bound::Unbounded => 0, + Bound::Included(&i) => i, + Bound::Excluded(&i) => i.saturating_add(1), + }; + let end = match range.end_bound() { + Bound::Excluded(&j) => j, + Bound::Included(&j) => j.saturating_add(1), + Bound::Unbounded => len, + }; + self.drain_range(start, end) + } + + fn drain_range(&mut self, start: usize, end: usize) -> Drain + { + let len = self.len(); + + // bounds check happens here (before length is changed!) + let range_slice: *const _ = &self[start..end]; + + // Calling `set_len` creates a fresh and thus unique mutable references, making all + // older aliases we created invalid. So we cannot call that function. + self.len = start as LenUint; + + unsafe { + Drain { + tail_start: end, + tail_len: len - end, + iter: (*range_slice).iter(), + vec: self as *mut _, + } + } + } + + /// Return the inner fixed size array, if it is full to its capacity. + /// + /// Return an `Ok` value with the array if length equals capacity, + /// return an `Err` with self otherwise. + pub fn into_inner(self) -> Result<[T; CAP], Self> { + if self.len() < self.capacity() { + Err(self) + } else { + unsafe { Ok(self.into_inner_unchecked()) } + } + } + + /// Return the inner fixed size array. + /// + /// Safety: + /// This operation is safe if and only if length equals capacity. + pub unsafe fn into_inner_unchecked(self) -> [T; CAP] { + debug_assert_eq!(self.len(), self.capacity()); + let array = ptr::read(self.as_ptr() as *const [T; CAP]); + array + } + + /// Returns the ArrayVecCopy, replacing the original with a new empty ArrayVecCopy. + /// + /// ``` + /// use arrayvec::ArrayVecCopy; + /// + /// let mut v = ArrayVecCopy::from([0, 1, 2, 3]); + /// assert_eq!([0, 1, 2, 3], v.take().into_inner().unwrap()); + /// assert!(v.is_empty()); + /// ``` + pub fn take(&mut self) -> Self { + mem::replace(self, Self::new()) + } + + /// Return a slice containing all elements of the vector. + pub fn as_slice(&self) -> &[T] { + ArrayVecImpl::as_slice(self) + } + + /// Return a mutable slice containing all elements of the vector. + pub fn as_mut_slice(&mut self) -> &mut [T] { + ArrayVecImpl::as_mut_slice(self) + } + + /// Return a raw pointer to the vector's buffer. + pub fn as_ptr(&self) -> *const T { + ArrayVecImpl::as_ptr(self) + } + + /// Return a raw mutable pointer to the vector's buffer. + pub fn as_mut_ptr(&mut self) -> *mut T { + ArrayVecImpl::as_mut_ptr(self) + } +} + +impl ArrayVecImpl for ArrayVecCopy { + type Item = T; + const CAPACITY: usize = CAP; + + fn len(&self) -> usize { self.len() } + + unsafe fn set_len(&mut self, length: usize) { + debug_assert!(length <= CAP); + self.len = length as LenUint; + } + + fn as_ptr(&self) -> *const Self::Item { + self.xs.as_ptr() as _ + } + + fn as_mut_ptr(&mut self) -> *mut Self::Item { + self.xs.as_mut_ptr() as _ + } +} + +impl Deref for ArrayVecCopy { + type Target = [T]; + #[inline] + fn deref(&self) -> &Self::Target { + self.as_slice() + } +} + +impl DerefMut for ArrayVecCopy { + #[inline] + fn deref_mut(&mut self) -> &mut Self::Target { + self.as_mut_slice() + } +} + + +/// Create an `ArrayVecCopy` from an array. +/// +/// ``` +/// use arrayvec::ArrayVecCopy; +/// +/// let mut array = ArrayVecCopy::from([1, 2, 3]); +/// assert_eq!(array.len(), 3); +/// assert_eq!(array.capacity(), 3); +/// ``` +impl From<[T; CAP]> for ArrayVecCopy { + #[track_caller] + fn from(array: [T; CAP]) -> Self { + let mut vec = >::new(); + unsafe { + (&array as *const [T; CAP] as *const [MaybeUninit; CAP]) + .copy_to_nonoverlapping(&mut vec.xs as *mut [MaybeUninit; CAP], 1); + vec.set_len(CAP); + } + vec + } +} + + +/// Try to create an `ArrayVecCopy` from a slice. This will return an error if the slice was too big to +/// fit. +/// +/// ``` +/// use arrayvec::ArrayVecCopy; +/// use std::convert::TryInto as _; +/// +/// let array: ArrayVecCopy<_, 4> = (&[1, 2, 3] as &[_]).try_into().unwrap(); +/// assert_eq!(array.len(), 3); +/// assert_eq!(array.capacity(), 4); +/// ``` +impl std::convert::TryFrom<&[T]> for ArrayVecCopy + where T: Clone, +{ + type Error = CapacityError; + + fn try_from(slice: &[T]) -> Result { + if Self::CAPACITY < slice.len() { + Err(CapacityError::new(())) + } else { + let mut array = Self::new(); + array.extend_from_slice(slice); + Ok(array) + } + } +} + + +/// Iterate the `ArrayVecCopy` with references to each element. +/// +/// ``` +/// use arrayvec::ArrayVecCopy; +/// +/// let array = ArrayVecCopy::from([1, 2, 3]); +/// +/// for elt in &array { +/// // ... +/// } +/// ``` +impl<'a, T: Copy + 'a, const CAP: usize> IntoIterator for &'a ArrayVecCopy { + type Item = &'a T; + type IntoIter = slice::Iter<'a, T>; + fn into_iter(self) -> Self::IntoIter { self.iter() } +} + +/// Iterate the `ArrayVecCopy` with mutable references to each element. +/// +/// ``` +/// use arrayvec::ArrayVecCopy; +/// +/// let mut array = ArrayVecCopy::from([1, 2, 3]); +/// +/// for elt in &mut array { +/// // ... +/// } +/// ``` +impl<'a, T: Copy + 'a, const CAP: usize> IntoIterator for &'a mut ArrayVecCopy { + type Item = &'a mut T; + type IntoIter = slice::IterMut<'a, T>; + fn into_iter(self) -> Self::IntoIter { self.iter_mut() } +} + +/// Iterate the `ArrayVecCopy` with each element by value. +/// +/// The vector is consumed by this operation. +/// +/// ``` +/// use arrayvec::ArrayVecCopy; +/// +/// for elt in ArrayVecCopy::from([1, 2, 3]) { +/// // ... +/// } +/// ``` +impl IntoIterator for ArrayVecCopy { + type Item = T; + type IntoIter = IntoIter; + fn into_iter(self) -> IntoIter { + IntoIter { index: 0, v: self, } + } +} + + +#[cfg(feature = "zeroize")] +/// "Best efforts" zeroing of the `ArrayVecCopy`'s buffer when the `zeroize` feature is enabled. +/// +/// The length is set to 0, and the buffer is dropped and zeroized. +/// Cannot ensure that previous moves of the `ArrayVecCopy` did not leave values on the stack. +/// +/// ``` +/// use arrayvec::ArrayVecCopy; +/// use zeroize::Zeroize; +/// let mut array = ArrayVecCopy::from([1, 2, 3]); +/// array.zeroize(); +/// assert_eq!(array.len(), 0); +/// let data = unsafe { core::slice::from_raw_parts(array.as_ptr(), array.capacity()) }; +/// assert_eq!(data, [0, 0, 0]); +/// ``` +impl zeroize::Zeroize for ArrayVecCopy { + fn zeroize(&mut self) { + // Zeroize all the contained elements. + self.iter_mut().zeroize(); + // Drop all the elements and set the length to 0. + self.clear(); + // Zeroize the backing array. + self.xs.zeroize(); + } +} + +/// By-value iterator for `ArrayVecCopy`. +pub struct IntoIter { + index: usize, + v: ArrayVecCopy, +} +impl IntoIter { + /// Returns the remaining items of this iterator as a slice. + pub fn as_slice(&self) -> &[T] { + &self.v[self.index..] + } + + /// Returns the remaining items of this iterator as a mutable slice. + pub fn as_mut_slice(&mut self) -> &mut [T] { + &mut self.v[self.index..] + } +} + +impl Iterator for IntoIter { + type Item = T; + + fn next(&mut self) -> Option { + if self.index == self.v.len() { + None + } else { + unsafe { + let index = self.index; + self.index = index + 1; + Some(ptr::read(self.v.get_unchecked_ptr(index))) + } + } + } + + fn size_hint(&self) -> (usize, Option) { + let len = self.v.len() - self.index; + (len, Some(len)) + } +} + +impl DoubleEndedIterator for IntoIter { + fn next_back(&mut self) -> Option { + if self.index == self.v.len() { + None + } else { + unsafe { + let new_len = self.v.len() - 1; + self.v.set_len(new_len); + Some(ptr::read(self.v.get_unchecked_ptr(new_len))) + } + } + } +} + +impl ExactSizeIterator for IntoIter { } + +impl Clone for IntoIter +where T: Clone, +{ + fn clone(&self) -> IntoIter { + let mut v = ArrayVecCopy::new(); + v.extend_from_slice(&self.v[self.index..]); + v.into_iter() + } +} + +impl fmt::Debug for IntoIter +where + T: fmt::Debug, +{ + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + f.debug_list() + .entries(&self.v[self.index..]) + .finish() + } +} + +/// A draining iterator for `ArrayVecCopy`. +pub struct Drain<'a, T: Copy + 'a, const CAP: usize> { + /// Index of tail to preserve + tail_start: usize, + /// Length of tail + tail_len: usize, + /// Current remaining range to remove + iter: slice::Iter<'a, T>, + vec: *mut ArrayVecCopy, +} + +unsafe impl<'a, T: Copy + Sync, const CAP: usize> Sync for Drain<'a, T, CAP> {} +unsafe impl<'a, T: Copy + Send, const CAP: usize> Send for Drain<'a, T, CAP> {} + +impl<'a, T: Copy + 'a, const CAP: usize> Iterator for Drain<'a, T, CAP> { + type Item = T; + + fn next(&mut self) -> Option { + self.iter.next().map(|elt| + unsafe { + ptr::read(elt as *const _) + } + ) + } + + fn size_hint(&self) -> (usize, Option) { + self.iter.size_hint() + } +} + +impl<'a, T: Copy + 'a, const CAP: usize> DoubleEndedIterator for Drain<'a, T, CAP> +{ + fn next_back(&mut self) -> Option { + self.iter.next_back().map(|elt| + unsafe { + ptr::read(elt as *const _) + } + ) + } +} + +impl<'a, T: Copy + 'a, const CAP: usize> ExactSizeIterator for Drain<'a, T, CAP> {} + +impl<'a, T: Copy + 'a, const CAP: usize> Drop for Drain<'a, T, CAP> { + fn drop(&mut self) { + // len is currently 0 so panicking while dropping will not cause a double drop. + + // exhaust self first + while let Some(_) = self.next() { } + + if self.tail_len > 0 { + unsafe { + let source_vec = &mut *self.vec; + // memmove back untouched tail, update to new length + let start = source_vec.len(); + let tail = self.tail_start; + let ptr = source_vec.as_mut_ptr(); + ptr::copy(ptr.add(tail), ptr.add(start), self.tail_len); + source_vec.set_len(start + self.tail_len); + } + } + } +} + +struct ScopeExitGuard + where F: FnMut(&Data, &mut T) +{ + value: T, + data: Data, + f: F, +} + +impl Drop for ScopeExitGuard + where F: FnMut(&Data, &mut T) +{ + fn drop(&mut self) { + (self.f)(&self.data, &mut self.value) + } +} + + + +/// Extend the `ArrayVecCopy` with an iterator. +/// +/// ***Panics*** if extending the vector exceeds its capacity. +impl Extend for ArrayVecCopy { + /// Extend the `ArrayVecCopy` with an iterator. + /// + /// ***Panics*** if extending the vector exceeds its capacity. + #[track_caller] + fn extend>(&mut self, iter: I) { + unsafe { + self.extend_from_iter::<_, true>(iter) + } + } +} + +#[inline(never)] +#[cold] +#[track_caller] +fn extend_panic() { + panic!("ArrayVecCopy: capacity exceeded in extend/from_iter"); +} + +impl ArrayVecCopy { + /// Extend the arrayvec from the iterable. + /// + /// ## Safety + /// + /// Unsafe because if CHECK is false, the length of the input is not checked. + /// The caller must ensure the length of the input fits in the capacity. + #[track_caller] + pub(crate) unsafe fn extend_from_iter(&mut self, iterable: I) + where I: IntoIterator + { + let take = self.capacity() - self.len(); + let len = self.len(); + let mut ptr = raw_ptr_add(self.as_mut_ptr(), len); + let end_ptr = raw_ptr_add(ptr, take); + // Keep the length in a separate variable, write it back on scope + // exit. To help the compiler with alias analysis and stuff. + // We update the length to handle panic in the iteration of the + // user's iterator, without dropping any elements on the floor. + let mut guard = ScopeExitGuard { + value: &mut self.len, + data: len, + f: move |&len, self_len| { + **self_len = len as LenUint; + } + }; + let mut iter = iterable.into_iter(); + loop { + if let Some(elt) = iter.next() { + if ptr == end_ptr && CHECK { extend_panic(); } + debug_assert_ne!(ptr, end_ptr); + if mem::size_of::() != 0 { + ptr.write(elt); + } + ptr = raw_ptr_add(ptr, 1); + guard.data += 1; + } else { + return; // success + } + } + } + + /// Extend the ArrayVecCopy with clones of elements from the slice; + /// the length of the slice must be <= the remaining capacity in the arrayvec. + pub(crate) fn extend_from_slice(&mut self, slice: &[T]) + where T: Clone + { + let take = self.capacity() - self.len(); + debug_assert!(slice.len() <= take); + unsafe { + let slice = if take < slice.len() { &slice[..take] } else { slice }; + self.extend_from_iter::<_, false>(slice.iter().cloned()); + } + } +} + +/// Rawptr add but uses arithmetic distance for ZST +unsafe fn raw_ptr_add(ptr: *mut T, offset: usize) -> *mut T { + if mem::size_of::() == 0 { + // Special case for ZST + ptr.cast::().wrapping_add(offset).cast::() + } else { + ptr.add(offset) + } +} + +/// Create an `ArrayVecCopy` from an iterator. +/// +/// ***Panics*** if the number of elements in the iterator exceeds the arrayvec's capacity. +impl iter::FromIterator for ArrayVecCopy { + /// Create an `ArrayVecCopy` from an iterator. + /// + /// ***Panics*** if the number of elements in the iterator exceeds the arrayvec's capacity. + fn from_iter>(iter: I) -> Self { + let mut array = ArrayVecCopy::new(); + array.extend(iter); + array + } +} + +impl Clone for ArrayVecCopy + where T: Clone +{ + fn clone(&self) -> Self { + self.iter().cloned().collect() + } + + fn clone_from(&mut self, rhs: &Self) { + // recursive case for the common prefix + let prefix = cmp::min(self.len(), rhs.len()); + self[..prefix].clone_from_slice(&rhs[..prefix]); + + if prefix < self.len() { + // rhs was shorter + self.truncate(prefix); + } else { + let rhs_elems = &rhs[self.len()..]; + self.extend_from_slice(rhs_elems); + } + } +} + +impl Hash for ArrayVecCopy + where T: Hash +{ + fn hash(&self, state: &mut H) { + Hash::hash(&**self, state) + } +} + +impl PartialEq for ArrayVecCopy + where T: PartialEq +{ + fn eq(&self, other: &Self) -> bool { + **self == **other + } +} + +impl PartialEq<[T]> for ArrayVecCopy + where T: PartialEq +{ + fn eq(&self, other: &[T]) -> bool { + **self == *other + } +} + +impl Eq for ArrayVecCopy where T: Eq { } + +impl Borrow<[T]> for ArrayVecCopy { + fn borrow(&self) -> &[T] { self } +} + +impl BorrowMut<[T]> for ArrayVecCopy { + fn borrow_mut(&mut self) -> &mut [T] { self } +} + +impl AsRef<[T]> for ArrayVecCopy { + fn as_ref(&self) -> &[T] { self } +} + +impl AsMut<[T]> for ArrayVecCopy { + fn as_mut(&mut self) -> &mut [T] { self } +} + +impl fmt::Debug for ArrayVecCopy where T: fmt::Debug { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { (**self).fmt(f) } +} + +impl Default for ArrayVecCopy { + /// Return an empty array + fn default() -> ArrayVecCopy { + ArrayVecCopy::new() + } +} + +impl PartialOrd for ArrayVecCopy where T: PartialOrd { + fn partial_cmp(&self, other: &Self) -> Option { + (**self).partial_cmp(other) + } + + fn lt(&self, other: &Self) -> bool { + (**self).lt(other) + } + + fn le(&self, other: &Self) -> bool { + (**self).le(other) + } + + fn ge(&self, other: &Self) -> bool { + (**self).ge(other) + } + + fn gt(&self, other: &Self) -> bool { + (**self).gt(other) + } +} + +impl Ord for ArrayVecCopy where T: Ord { + fn cmp(&self, other: &Self) -> cmp::Ordering { + (**self).cmp(other) + } +} + +#[cfg(feature="std")] +/// `Write` appends written data to the end of the vector. +/// +/// Requires `features="std"`. +impl io::Write for ArrayVecCopy { + fn write(&mut self, data: &[u8]) -> io::Result { + let len = cmp::min(self.remaining_capacity(), data.len()); + let _result = self.try_extend_from_slice(&data[..len]); + debug_assert!(_result.is_ok()); + Ok(len) + } + fn flush(&mut self) -> io::Result<()> { Ok(()) } +} + +#[cfg(feature="serde")] +/// Requires crate feature `"serde"` +impl Serialize for ArrayVecCopy { + fn serialize(&self, serializer: S) -> Result + where S: Serializer + { + serializer.collect_seq(self) + } +} + +#[cfg(feature="serde")] +/// Requires crate feature `"serde"` +impl<'de, T: Deserialize<'de>, const CAP: usize> Deserialize<'de> for ArrayVecCopy { + fn deserialize(deserializer: D) -> Result + where D: Deserializer<'de> + { + use serde::de::{Visitor, SeqAccess, Error}; + use std::marker::PhantomData; + + struct ArrayVecCopyVisitor<'de, T: Deserialize<'de>, const CAP: usize>(PhantomData<(&'de (), [T; CAP])>); + + impl<'de, T: Deserialize<'de>, const CAP: usize> Visitor<'de> for ArrayVecCopyVisitor<'de, T, CAP> { + type Value = ArrayVecCopy; + + fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result { + write!(formatter, "an array with no more than {} items", CAP) + } + + fn visit_seq(self, mut seq: SA) -> Result + where SA: SeqAccess<'de>, + { + let mut values = ArrayVecCopy::::new(); + + while let Some(value) = seq.next_element()? { + if let Err(_) = values.try_push(value) { + return Err(SA::Error::invalid_length(CAP + 1, &self)); + } + } + + Ok(values) + } + } + + deserializer.deserialize_seq(ArrayVecCopyVisitor::(PhantomData)) + } +} + +#[cfg(feature = "borsh")] +/// Requires crate feature `"borsh"` +impl borsh::BorshSerialize for ArrayVecCopy +where + T: borsh::BorshSerialize, +{ + fn serialize(&self, writer: &mut W) -> borsh::io::Result<()> { + <[T] as borsh::BorshSerialize>::serialize(self.as_slice(), writer) + } +} + +#[cfg(feature = "borsh")] +/// Requires crate feature `"borsh"` +impl borsh::BorshDeserialize for ArrayVecCopy +where + T: borsh::BorshDeserialize, +{ + fn deserialize_reader(reader: &mut R) -> borsh::io::Result { + let mut values = Self::new(); + let len = ::deserialize_reader(reader)?; + for _ in 0..len { + let elem = ::deserialize_reader(reader)?; + if let Err(_) = values.try_push(elem) { + return Err(borsh::io::Error::new( + borsh::io::ErrorKind::InvalidData, + format!("Expected an array with no more than {} items", CAP), + )); + } + } + + Ok(values) + } +} diff --git a/src/lib.rs b/src/lib.rs index f9a2fe6..09fd07e 100644 --- a/src/lib.rs +++ b/src/lib.rs @@ -50,6 +50,7 @@ macro_rules! assert_capacity_limit_const { } } +mod arrayvec_copy; mod arrayvec_impl; mod arrayvec; mod array_string; @@ -57,6 +58,11 @@ mod char; mod errors; mod utils; +pub mod copy { + pub use crate::arrayvec_copy::{Drain, IntoIter}; +} + +pub use crate::arrayvec_copy::ArrayVecCopy; pub use crate::array_string::ArrayString; pub use crate::errors::CapacityError;