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#![no_std] #![allow(incomplete_features)] #![feature(const_fn)] #![feature(const_generics)] #![feature(const_if_match)] #![feature(const_raw_ptr_to_usize_cast)] #![feature(core_intrinsics)] #![feature(doc_cfg)] #![feature(exact_size_is_empty)] #![feature(maybe_uninit_extra)] #![feature(maybe_uninit_ref)] #![feature(maybe_uninit_uninit_array)] #![cfg_attr(feature = "std", feature(read_initializer))] #![feature(slice_partition_dedup)] #![feature(specialization)] #![feature(trusted_len)] pub use crate::errors::PushCapacityError; pub use crate::iterators::*; pub use crate::trait_impls::*; use crate::utils::*; use core::cmp::{Ord, PartialEq}; use core::intrinsics; use core::marker::PhantomData; use core::mem::{self, MaybeUninit}; use core::ops::{Bound::Excluded, Bound::Included, Bound::Unbounded, RangeBounds}; use core::ptr; use core::slice; #[cfg(any(feature = "std", rustdoc))] extern crate alloc; #[cfg(feature = "std")] extern crate std; #[cfg(any(feature = "std", rustdoc))] use alloc::vec::Vec; mod iterators; #[macro_use] mod macros; #[doc(hidden)] mod errors; mod trait_impls; #[doc(hidden)] pub mod utils; /// A [`Vec`](alloc::vec::Vec)-like struct (mostly directly API-compatible where it can be) /// implemented with const generics around an array of fixed `N` capacity. pub struct StaticVec<T, const N: usize> { data: [MaybeUninit<T>; N], length: usize, } impl<T, const N: usize> StaticVec<T, N> { /// Returns a new StaticVec instance. #[inline(always)] pub fn new() -> Self { Self { data: Self::new_data(), length: 0, } } /// Returns a new StaticVec instance filled with the contents, if any, of a slice reference, /// which can be either `&mut` or `&` as if it is `&mut` it will implicitly coerce to `&`. /// If the slice has a length greater than the StaticVec's declared capacity, /// any contents after that point are ignored. /// Locally requires that `T` implements [`Copy`](core::marker::Copy) to avoid soundness issues. #[inline] pub fn new_from_slice(values: &[T]) -> Self where T: Copy { let length = values.len().min(N); Self { data: { let mut data = Self::new_data_uninit(); unsafe { values .as_ptr() .copy_to_nonoverlapping(data.as_mut_ptr() as *mut T, length); data.assume_init() } }, length, } } /// Returns a new StaticVec instance filled with the contents, if any, of an array. /// If the array has a length greater than the StaticVec's declared capacity, /// any contents after that point are ignored. /// /// The `N2` parameter does not need to be provided explicitly, and can be inferred from the array /// itself. This function does *not* leak memory, as any ignored extra elements in the source /// array are explicitly dropped with [`drop_in_place`](core::ptr::drop_in_place) before /// [`forget`](core::mem::forget) is called on it. /// /// Example usage: /// ``` /// // Same input length as the declared capacity: /// let v = StaticVec::<i32, 3>::new_from_array([1, 2, 3]); /// assert_eq!(v, [1, 2, 3]); /// // Truncated to fit the declared capacity: /// let v2 = StaticVec::<i32, 3>::new_from_array([1, 2, 3, 4, 5, 6]); /// assert_eq!(v2, [1, 2, 3]); /// ``` /// Note that StaticVec also implements [`From`](std::convert::From) for both slices and static /// arrays, which may prove more ergonomic in some cases as it allows for a greater degree of /// type inference: /// ``` /// // The StaticVec on the next line is inferred to be of type `StaticVec<&'static str, 4>`. /// let v = StaticVec::from(["A", "B", "C", "D"]); /// ``` #[inline] pub fn new_from_array<const N2: usize>(mut values: [T; N2]) -> Self { if N == N2 { Self::from(values) } else { Self { data: { unsafe { let mut data = Self::new_data_uninit(); values .as_ptr() .copy_to_nonoverlapping(data.as_mut_ptr() as *mut T, N2.min(N)); // Drops any extra values left in the source array, then "forgets it". ptr::drop_in_place(values.get_unchecked_mut(N2.min(N)..N2)); mem::forget(values); data.assume_init() } }, length: N2.min(N), } } } /// Returns a new StaticVec instance filled with the return value of an initializer function. /// The length field of the newly created StaticVec will be equal to its capacity. /// /// Example usage: /// ``` /// let mut i = 0; /// let v = StaticVec::<i32, 64>::filled_with(|| { i += 1; i }); /// assert_eq!(v.len(), 64); /// assert_eq!(v[0], 1); /// assert_eq!(v[1], 2); /// assert_eq!(v[2], 3); /// assert_eq!(v[3], 4); /// ``` #[inline] pub fn filled_with<F>(mut initializer: F) -> Self where F: FnMut() -> T { let mut res = Self::new(); // You might think it would make more sense to use `push_unchecked` here. // Originally, I did also! However, as of today (November 19, 2019), doing so // both in this function and several others throughout the crate inhibits the ability // of `rustc` to fully unroll and autovectorize various constant-bounds loops. If this changes // in the future, feel free to open a PR switching out the manual code for `get_unchecked`, if // you happen to notice it before I do. for i in 0..N { unsafe { res.data.get_unchecked_mut(i).write(initializer()); res.length += 1; } } res } /// Returns a new StaticVec instance filled with the return value of an initializer function. /// Unlike for [`filled_with`](crate::StaticVec::filled_with), the initializer function in /// this case must take a single usize variable as an input parameter, which will be called /// with the current index of the `0..N` loop that /// [`filled_with_by_index`](crate::StaticVec::filled_with_by_index) is implemented with /// internally. The length field of the newly created StaticVec will be equal to its capacity. /// /// Example usage: /// ``` /// let v = StaticVec::<usize, 64>::filled_with_by_index(|i| { i + 1 }); /// assert_eq!(v.len(), 64); /// assert_eq!(v[0], 1); /// assert_eq!(v[1], 2); /// assert_eq!(v[2], 3); /// assert_eq!(v[3], 4); /// ``` #[inline] pub fn filled_with_by_index<F>(mut initializer: F) -> Self where F: FnMut(usize) -> T { let mut res = Self::new(); for i in 0..N { unsafe { res.data.get_unchecked_mut(i).write(initializer(i)); res.length += 1; } } res } /// Returns the current length of the StaticVec. /// Just as for a normal [`Vec`](alloc::vec::Vec), this means the number of elements that /// have been added to it with [`push`](crate::StaticVec::push), /// [`insert`](crate::StaticVec::insert), etc. except in the case that it has been set directly /// with the unsafe [`set_len`](crate::StaticVec::set_len) function. #[inline(always)] pub const fn len(&self) -> usize { self.length } /// Returns the total capacity of the StaticVec. /// This is always equivalent to the generic `N` parameter it was declared with, /// which determines the fixed size of the backing array. #[inline(always)] pub const fn capacity(&self) -> usize { N } /// Does the same thing as [`capacity`](crate::StaticVec::capacity), but as an associated /// function rather than a method. #[inline(always)] pub const fn cap() -> usize { N } /// Serves the same purpose as [`capacity`](crate::StaticVec::capacity), but as an associated /// constant rather than a method. pub const CAPACITY: usize = N; /// Returns the remaining capacity of the StaticVec. #[inline(always)] pub const fn remaining_capacity(&self) -> usize { N - self.length } /// Directly sets the length field of the StaticVec to `new_len`. Useful if you intend /// to write to it solely element-wise, but marked unsafe due to how it creates /// the potential for reading from uninitialized memory later on. /// /// # Safety /// /// It is up to the caller to ensure that `new_len` is less than or equal to the StaticVec's /// constant `N` parameter, and that the range of elements covered by a length of `new_len` is /// actually initialized. Failure to do so will almost certainly result in undefined behavior. #[inline(always)] pub unsafe fn set_len(&mut self, new_len: usize) { debug_assert!( new_len <= N, "Attempted to unsafely set length to {}; maximum is {}!", new_len, N ); self.length = new_len; } /// Returns true if the current length of the StaticVec is 0. #[inline(always)] pub const fn is_empty(&self) -> bool { self.length == 0 } /// Returns true if the current length of the StaticVec is greater than 0. #[inline(always)] pub const fn is_not_empty(&self) -> bool { self.length > 0 } /// Returns true if the current length of the StaticVec is equal to its capacity. #[inline(always)] pub const fn is_full(&self) -> bool { self.length == N } /// Returns true if the current length of the StaticVec is less than its capacity. #[inline(always)] pub const fn is_not_full(&self) -> bool { self.length < N } /// Returns a constant pointer to the first element of the StaticVec's internal array. #[inline(always)] pub fn as_ptr(&self) -> *const T { self.data.as_ptr() as *const T } /// Returns a mutable pointer to the first element of the StaticVec's internal array. #[inline(always)] pub fn as_mut_ptr(&mut self) -> *mut T { self.data.as_mut_ptr() as *mut T } /// Returns a constant reference to a slice of the StaticVec's inhabited area. #[inline(always)] pub fn as_slice(&self) -> &[T] { // Safety: `self.as_ptr()` is a pointer to an array for which the first `length` // elements are guaranteed to be initialized. Therefore this is a valid slice. unsafe { slice::from_raw_parts(self.as_ptr(), self.length) } } /// Returns a mutable reference to a slice of the StaticVec's inhabited area. #[inline(always)] pub fn as_mut_slice(&mut self) -> &mut [T] { // Safety: See as_slice. unsafe { slice::from_raw_parts_mut(self.as_mut_ptr(), self.length) } } /// Returns a constant reference to the element of the StaticVec at `index`, /// if `index` is within the range `0..length`. No checks are performed to /// ensure that is the case, so this function is marked `unsafe` and should /// be used with caution only when performance is absolutely paramount. /// /// Note that unlike [`slice::get_unchecked`](https://doc.rust-lang.org/nightly/std/primitive.slice.html#method.get_unchecked), /// this method only supports accessing individual elements via `usize`; it cannot also produce /// subslices. To unsafely get a subslice without a bounds check, use /// `self.as_slice().get_unchecked(a..b)`. /// /// # Safety /// /// It is up to the caller to ensure that `index` is within the appropriate bounds. #[inline(always)] pub unsafe fn get_unchecked(&self, index: usize) -> &T { debug_assert!( index < self.length, "Attempted to unsafely get at index {} when length is {}!", index, self.length ); self.data.get_unchecked(index).get_ref() } /// Returns a mutable reference to the element of the StaticVec at `index`, /// if `index` is within the range `0..length`. No checks are performed to /// ensure that is the case, so this function is marked `unsafe` and should /// be used with caution only when performance is absolutely paramount. /// /// The same differences between this method and the slice method of the same name /// apply as do for [`get_unchecked`](crate::StaticVec::get_unchecked). /// /// # Safety /// /// It is up to the caller to ensure that `index` is within the appropriate bounds. #[inline(always)] pub unsafe fn get_unchecked_mut(&mut self, index: usize) -> &mut T { debug_assert!( index < self.length, "Attempted to unsafely get at index {} when length is {}!", index, self.length ); self.data.get_unchecked_mut(index).get_mut() } /// Returns a constant pointer to the element of the StaticVec at `index` without doing any /// checking to ensure that `index` is within the range `0..length`. The return value of this /// function is equivalent to what would be returned from `as_ptr().add(index)`. /// /// # Safety /// /// It is up to the caller to ensure that `index` is within the appropriate bounds such that the /// function returns a pointer to valid data. #[inline(always)] pub unsafe fn ptr_at_unchecked(&self, index: usize) -> *const T { self.as_ptr().add(index) } /// Returns a mutable pointer to the element of the StaticVec at `index` without doing any /// checking to ensure that `index` is within the range `0..length`. The return value of this /// function is equivalent to what would be returned from `as_mut_ptr().add(index)`. /// /// # Safety /// /// It is up to the caller to ensure that `index` is within the appropriate bounds such that the /// function returns a pointer to valid data. #[inline(always)] pub unsafe fn mut_ptr_at_unchecked(&mut self, index: usize) -> *mut T { self.as_mut_ptr().add(index) } /// Returns a constant pointer to the element of the StaticVec at `index` if `index` /// is within the range `0..length`, or panics if it is not. The return value of this function is /// equivalent to what would be returned from `as_ptr().add(index)`. #[inline(always)] pub fn ptr_at(&self, index: usize) -> *const T { assert!( index < self.length, "Provided index {} must be between 0 and {}!", index, self.length ); unsafe { self.ptr_at_unchecked(index) } } /// Returns a mutable pointer to the element of the StaticVec at `index` if `index` /// is within the range `0..length`, or panics if it is not. The return value of this function is /// equivalent to what would be returned from `as_mut_ptr().add(index)`. #[inline(always)] pub fn mut_ptr_at(&mut self, index: usize) -> *mut T { assert!( index < self.length, "Provided index {} must be between 0 and {}!", index, self.length ); unsafe { self.mut_ptr_at_unchecked(index) } } /// Appends a value to the end of the StaticVec without asserting that /// its current length is less than `N`. /// /// # Safety /// /// It is up to the caller to ensure that the length of the StaticVec /// prior to using this function is less than `N`. Failure to do so will result /// in writing to an out-of-bounds memory region. #[inline(always)] pub unsafe fn push_unchecked(&mut self, value: T) { debug_assert!( self.is_not_full(), "Attempted to unsafely push to a full StaticVec!" ); self.mut_ptr_at_unchecked(self.length).write(value); self.length += 1; } /// Pops a value from the end of the StaticVec and returns it directly without asserting that /// the StaticVec's current length is greater than 0. /// /// # Safety /// /// It is up to the caller to ensure that the StaticVec contains at least one /// element prior to using this function. Failure to do so will result in reading /// from uninitialized memory. #[inline(always)] pub unsafe fn pop_unchecked(&mut self) -> T { debug_assert!( self.is_not_empty(), "Attempted to unsafely pop from an empty StaticVec!" ); self.length -= 1; self.ptr_at_unchecked(self.length).read() } /// Pushes `value` to the StaticVec if its current length is less than its capacity, /// or returns an error indicating there's no remaining capacity otherwise. #[inline(always)] pub fn try_push(&mut self, value: T) -> Result<(), PushCapacityError<T, N>> { if self.length < N { unsafe { self.push_unchecked(value) }; Ok(()) } else { Err(PushCapacityError::new(value)) } } /// Pushes a value to the end of the StaticVec. Panics if the collection is /// full; that is, if `self.len() == self.capacity()`. #[inline(always)] pub fn push(&mut self, value: T) { self .try_push(value) .expect("Insufficient remaining capacity for push!") } /// Removes the value at the last position of the StaticVec and returns it in `Some` if /// the StaticVec has a current length greater than 0, and returns `None` otherwise. #[inline(always)] pub fn pop(&mut self) -> Option<T> { if self.is_empty() { None } else { Some(unsafe { self.pop_unchecked() }) } } /// Returns a constant reference to the first element of the StaticVec in `Some` if the StaticVec /// is not empty, or `None` otherwise. #[inline(always)] pub fn first(&self) -> Option<&T> { if self.is_empty() { None } else { Some(unsafe { self.get_unchecked(0) }) } } /// Returns a mutable reference to the first element of the StaticVec in `Some` if the StaticVec /// is not empty, or `None` otherwise. #[inline(always)] pub fn first_mut(&mut self) -> Option<&mut T> { if self.is_empty() { None } else { Some(unsafe { self.get_unchecked_mut(0) }) } } /// Returns a constant reference to the last element of the StaticVec in `Some` if the StaticVec /// is not empty, or `None` otherwise. #[inline(always)] pub fn last(&self) -> Option<&T> { if self.is_empty() { None } else { Some(unsafe { self.get_unchecked(self.length - 1) }) } } /// Returns a mutable reference to the last element of the StaticVec in `Some` if the StaticVec is /// not empty, or `None` otherwise. #[inline(always)] pub fn last_mut(&mut self) -> Option<&mut T> { if self.is_empty() { None } else { Some(unsafe { self.get_unchecked_mut(self.length - 1) }) } } /// Asserts that `index` is less than the current length of the StaticVec, /// and if so removes the value at that position and returns it. Any values /// that exist in later positions are shifted to the left. #[inline] pub fn remove(&mut self, index: usize) -> T { assert!(index < self.length); unsafe { let p = self.mut_ptr_at_unchecked(index); let res = p.read(); p.offset(1).copy_to(p, self.length - index - 1); self.length -= 1; res } } /// Removes the first instance of `item` from the StaticVec if the item exists. #[inline(always)] pub fn remove_item(&mut self, item: &T) -> Option<T> where T: PartialEq { // Adapted this from normal Vec's implementation. if let Some(pos) = self.iter().position(|x| *x == *item) { Some(self.remove(pos)) } else { None } } /// Returns `None` if `index` is greater than or equal to the current length of the StaticVec. /// otherwise, removes the value at that position and returns it in `Some`, and then /// moves the last value in the StaticVec into the empty slot. #[inline(always)] pub fn swap_pop(&mut self, index: usize) -> Option<T> { if index < self.length { unsafe { let last_value = self.data.get_unchecked(self.length - 1).read(); self.length -= 1; Some(self.mut_ptr_at_unchecked(index).replace(last_value)) } } else { None } } /// Asserts that `index` is less than the current length of the StaticVec, /// and if so removes the value at that position and returns it, and then /// moves the last value in the StaticVec into the empty slot. #[inline(always)] pub fn swap_remove(&mut self, index: usize) -> T { assert!(index < self.length); unsafe { let last_value = self.data.get_unchecked(self.length - 1).read(); self.length -= 1; self.mut_ptr_at_unchecked(index).replace(last_value) } } /// Asserts that the current length of the StaticVec is less than `N` and that /// `index` is less than the length, and if so inserts `value` at that position. /// Any values that exist in positions after `index` are shifted to the right. #[inline] pub fn insert(&mut self, index: usize, value: T) { assert!(self.length < N && index <= self.length); unsafe { let p = self.mut_ptr_at_unchecked(index); p.copy_to(p.offset(1), self.length - index); p.write(value); self.length += 1; } } /// Inserts `value` at `index` if the current length of the StaticVec is less than `N` and `index` /// is less than the length, or returns a error stating one of the two is not the case otherwise. /// Any values that exist in positions after `index` are shifted to the right. #[inline] pub fn try_insert(&mut self, index: usize, value: T) -> Result<(), &'static str> { if self.length < N && index <= self.length { unsafe { let p = self.mut_ptr_at_unchecked(index); p.copy_to(p.offset(1), self.length - index); p.write(value); self.length += 1; Ok(()) } } else { Err("One of `self.length < N` or `index <= self.length` is false!") } } /// Removes all contents from the StaticVec and sets its length back to 0. #[inline(always)] pub fn clear(&mut self) { unsafe { ptr::drop_in_place(self.as_mut_slice()); } self.length = 0; } /// Returns a [`StaticVecIterConst`](crate::iterators::StaticVecIterConst) over the StaticVec's /// inhabited area. #[inline(always)] pub fn iter(&self) -> StaticVecIterConst<T, N> { StaticVecIterConst { start: self.as_ptr(), end: match intrinsics::size_of::<T>() { 0 => (self.as_ptr() as *const u8).wrapping_add(self.length) as *const T, _ => unsafe { self.ptr_at_unchecked(self.length) }, }, marker: PhantomData, } } /// Returns a [`StaticVecIterMut`](crate::iterators::StaticVecIterMut) over the StaticVec's /// inhabited area. #[inline(always)] pub fn iter_mut(&mut self) -> StaticVecIterMut<T, N> { StaticVecIterMut { start: self.as_mut_ptr(), end: match intrinsics::size_of::<T>() { 0 => (self.as_mut_ptr() as *mut u8).wrapping_add(self.length) as *mut T, _ => unsafe { self.mut_ptr_at_unchecked(self.length) }, }, marker: PhantomData, } } /// Returns a separate, stable-sorted StaticVec of the contents of the /// StaticVec's inhabited area without modifying the original data. /// Locally requires that `T` implements [`Copy`](core::marker::Copy) to avoid soundness issues, /// and [`Ord`](core::cmp::Ord) to make the sorting possible. #[cfg(feature = "std")] #[doc(cfg(feature = "std"))] #[inline] pub fn sorted(&self) -> Self where T: Copy + Ord { let mut res = self.clone(); res.sort(); res } /// Returns a separate, unstable-sorted StaticVec of the contents of the /// StaticVec's inhabited area without modifying the original data. /// Locally requires that `T` implements [`Copy`](core::marker::Copy) to avoid soundness issues, /// and [`Ord`](core::cmp::Ord) to make the sorting possible. #[inline] pub fn sorted_unstable(&self) -> Self where T: Copy + Ord { let mut res = self.clone(); res.sort_unstable(); res } /// Returns a separate, reversed StaticVec of the contents of the StaticVec's /// inhabited area without modifying the original data. /// Locally requires that `T` implements [`Copy`](core::marker::Copy) to avoid soundness issues. #[inline] pub fn reversed(&self) -> Self where T: Copy { Self { data: unsafe { let mut res = Self::new_data_uninit(); reverse_copy( self.as_ptr(), self.ptr_at_unchecked(self.length), res.as_mut_ptr() as *mut T, ); res.assume_init() }, length: self.length, } } /// Copies and appends all elements, if any, of a slice (which can also be `&mut` as it will /// coerce implicitly to `&`) to the StaticVec. If the slice has a length greater than the /// StaticVec's remaining capacity, any contents after that point are ignored. /// Locally requires that `T` implements [`Copy`](core::marker::Copy) to avoid soundness issues. #[inline(always)] pub fn extend_from_slice(&mut self, other: &[T]) where T: Copy { let added_length = other.len().min(self.remaining_capacity()); // Safety: added_length is <= our remaining capacity and other.len. unsafe { other .as_ptr() .copy_to_nonoverlapping(self.mut_ptr_at_unchecked(self.length), added_length); } self.length += added_length; } /// Copies and appends all elements, if any, of a slice to the StaticVec if the /// StaticVec's remaining capacity is greater than the length of the slice, or returns /// an error indicating that's not the case otherwise. #[inline(always)] pub fn try_extend_from_slice(&mut self, other: &[T]) -> Result<(), &'static str> where T: Copy { let added_length = other.len(); if self.remaining_capacity() < added_length { return Err("Insufficient remaining capacity!"); } unsafe { other .as_ptr() .copy_to_nonoverlapping(self.mut_ptr_at_unchecked(self.length), added_length); } self.length += added_length; Ok(()) } /// Appends `self.remaining_capacity()` (or as many as available) items from /// `other` to `self`. The appended items (if any) will no longer exist in `other` afterwards, /// as `other`'s `length` field will be adjusted to indicate. /// /// The `N2` parameter does not need to be provided explicitly, and can be inferred directly from /// the constant `N2` constraint of `other` (which may or may not be the same as the `N` /// constraint of `self`.) #[inline] pub fn append<const N2: usize>(&mut self, other: &mut StaticVec<T, N2>) { let item_count = self.remaining_capacity().min(other.length); let other_new_length = other.length - item_count; unsafe { self .mut_ptr_at_unchecked(self.length) .copy_from_nonoverlapping(other.as_ptr(), item_count); other .as_mut_ptr() .copy_from(other.ptr_at_unchecked(item_count), other_new_length); } other.length = other_new_length; self.length += item_count; } /// Returns a [`Vec`](alloc::vec::Vec) containing the contents of the StaticVec instance. /// The returned [`Vec`](alloc::vec::Vec) will initially have the same value for /// [`len`](alloc::vec::Vec::len) and [`capacity`](alloc::vec::Vec::capacity) as the source /// StaticVec. Note that while using this function does *not* consume the source StaticVec in /// the sense of rendering it completely inaccessible / unusable, it *does* empty it (that is, /// it will have no contents and a length of 0 afterwards.) #[cfg(feature = "std")] #[doc(cfg(feature = "std"))] #[allow(clippy::wrong_self_convention)] #[inline(always)] pub fn into_vec(&mut self) -> Vec<T> { let mut res = Vec::with_capacity(N); unsafe { self .as_ptr() .copy_to_nonoverlapping(res.as_mut_ptr(), self.length); res.set_len(self.length); self.length = 0; res } } /// Removes the specified range of elements from the StaticVec and returns them in a new one. #[inline] pub fn drain<R>(&mut self, range: R) -> Self // No Copy bounds here because the original StaticVec gives up all access to the values in // question. where R: RangeBounds<usize> { // Borrowed this part from normal Vec's implementation. let start = match range.start_bound() { Included(&idx) => idx, Excluded(&idx) => idx + 1, Unbounded => 0, }; let end = match range.end_bound() { Included(&idx) => idx + 1, Excluded(&idx) => idx, Unbounded => self.length, }; assert!(start <= end && end <= self.length); let res_length = end - start; Self { data: { let mut res = Self::new_data_uninit(); unsafe { self .ptr_at_unchecked(start) .copy_to_nonoverlapping(res.as_mut_ptr() as *mut T, res_length); self .ptr_at_unchecked(end) .copy_to(self.mut_ptr_at_unchecked(start), self.length - end); self.length -= res_length; res.assume_init() } }, length: res_length, } } /// Removes all elements in the StaticVec for which `filter` returns true and /// returns them in a new one. #[inline] pub fn drain_filter<F>(&mut self, mut filter: F) -> Self where F: FnMut(&mut T) -> bool { let mut res = Self::new(); let old_length = self.length; self.length = 0; unsafe { for i in 0..old_length { let val = self.mut_ptr_at_unchecked(i); if filter(&mut *val) { res.data.get_unchecked_mut(res.length).write(val.read()); res.length += 1; } else if res.length > 0 { self .ptr_at_unchecked(i) .copy_to_nonoverlapping(self.mut_ptr_at_unchecked(i - res.length), 1); } } } self.length = old_length - res.length; res } /// Removes all elements in the StaticVec for which `filter` returns false. #[inline(always)] pub fn retain<F>(&mut self, mut filter: F) where F: FnMut(&T) -> bool { self.drain_filter(|val| !filter(val)); } /// Shortens the StaticVec, keeping the first `length` elements and dropping the rest. /// Does nothing if `length` is greater than or equal to the current length of the StaticVec. #[inline(always)] pub fn truncate(&mut self, length: usize) { if length < self.length { let old_length = self.length; self.length = length; unsafe { ptr::drop_in_place(self.as_mut_slice().get_unchecked_mut(length..old_length)); } } } /// Splits the StaticVec into two at the given index. /// The original StaticVec will contain elements `0..at`, /// and the new one will contain elements `at..length`. #[inline] pub fn split_off(&mut self, at: usize) -> Self { assert!(at <= self.length); let split_length = self.length - at; self.length = at; Self { data: unsafe { let mut split = Self::new_data_uninit(); self .ptr_at_unchecked(at) .copy_to_nonoverlapping(split.as_mut_ptr() as *mut T, split_length); split.assume_init() }, length: split_length, } } /// Removes all but the first of consecutive elements in the StaticVec satisfying a given equality /// relation. #[inline(always)] pub fn dedup_by<F>(&mut self, same_bucket: F) where F: FnMut(&mut T, &mut T) -> bool { // Mostly the same as Vec's version. let new_length = self.as_mut_slice().partition_dedup_by(same_bucket).0.len(); self.truncate(new_length); } /// Removes consecutive repeated elements in the StaticVec according to the /// locally required [`PartialEq`](core::cmp::PartialEq) trait implementation for `T`. #[inline(always)] pub fn dedup(&mut self) where T: PartialEq { // Exactly the same as Vec's version. self.dedup_by(|a, b| a == b) } /// Removes all but the first of consecutive elements in the StaticVec that /// resolve to the same key. #[inline(always)] pub fn dedup_by_key<F, K>(&mut self, mut key: F) where F: FnMut(&mut T) -> K, K: PartialEq<K>, { // Exactly the same as Vec's version. self.dedup_by(|a, b| key(a) == key(b)) } /// Returns a new StaticVec representing the difference of `self` and `other` (that is, /// all items present in `self`, but *not* present in `other`.) /// /// The `N2` parameter does not need to be provided explicitly, and can be inferred from `other` /// itself. /// /// Locally requires that `T` implements [`Clone`](core::clone::Clone) to avoid soundness issues /// while accommodating for more types than [`Copy`](core::marker::Copy) would appropriately for /// this function, and [`PartialEq`](core::cmp::PartialEq) to make the item comparisons possible. /// /// Example usage: /// ``` /// assert_eq!( /// staticvec![4, 5, 6, 7].difference(&staticvec![1, 2, 3, 7]), /// [4, 5, 6] /// ); /// ``` #[inline] pub fn difference<const N2: usize>(&self, other: &StaticVec<T, N2>) -> Self where T: Clone + PartialEq { let min_length = self.length.min(other.length); let right = other.as_slice(); let mut res = Self::new(); for i in 0..min_length { let current = unsafe { self.get_unchecked(i) }; match right.iter().find(|&item| item == current).is_some() { true => (), false => unsafe { res.push_unchecked((*current).clone()) }, } } res } /// Returns a new StaticVec representing the symmetric difference of `self` and `other` (that is, /// all items present in at least one of `self` or `other`, but *not* present in both.) /// /// The `N2` parameter does not need to be provided explicitly, and can be inferred from `other` /// itself. /// /// Locally requires that `T` implements [`Clone`](core::clone::Clone) to avoid soundness issues /// while accommodating for more types than [`Copy`](core::marker::Copy) would appropriately for /// this function, and [`PartialEq`](core::cmp::PartialEq) to make the item comparisons possible. /// /// Example usage: /// ``` /// assert_eq!( /// staticvec![1, 2, 3].symmetric_difference(&staticvec![3, 4, 5]), /// [1, 2, 4, 5] /// ); /// ``` #[inline] pub fn symmetric_difference<const N2: usize>( &self, other: &StaticVec<T, N2>, ) -> StaticVec<T, { N + N2 }> where T: Clone + PartialEq, { let min_length = self.length.min(other.length); let left = self.as_slice(); let right = other.as_slice(); let mut res = StaticVec::new(); for i in 0..min_length { let (current_left, current_right) = unsafe { (self.get_unchecked(i), other.get_unchecked(i)) }; match right.iter().find(|&item| item == current_left).is_some() { true => (), false => unsafe { res.push_unchecked((*current_left).clone()) }, } match left.iter().find(|&item| item == current_right).is_some() { true => (), false => unsafe { res.push_unchecked((*current_right).clone()) }, } } res } #[doc(hidden)] #[inline(always)] pub(crate) fn new_data() -> [MaybeUninit<T>; N] { // An internal convenience function to get an *initialized* instance of `[MaybeUninit<T>; N]`. MaybeUninit::uninit_array() } #[doc(hidden)] #[inline(always)] pub(crate) const fn new_data_uninit() -> MaybeUninit<[MaybeUninit<T>; N]> { // An internal convenience function to get an *uninitialized* instance of // `MaybeUninit<[MaybeUninit<T>; N]>`. MaybeUninit::uninit() } }