| // Copyright 2014 The Rust Project Developers. See the COPYRIGHT |
| // file at the top-level directory of this distribution and at |
| // http://rust-lang.org/COPYRIGHT. |
| // |
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| |
| //! A contiguous growable array type with heap-allocated contents, written |
| //! `Vec<'bump, T>`. |
| //! |
| //! Vectors have `O(1)` indexing, amortized `O(1)` push (to the end) and |
| //! `O(1)` pop (from the end). |
| //! |
| //! # Examples |
| //! |
| //! You can explicitly create a [`Vec<'bump, T>`] with [`new`]: |
| //! |
| //! ``` |
| //! use bumpalo::{Bump, collections::Vec}; |
| //! |
| //! let b = Bump::new(); |
| //! let v: Vec<i32> = Vec::new_in(&b); |
| //! ``` |
| //! |
| //! ...or by using the [`vec!`] macro: |
| //! |
| //! ``` |
| //! use bumpalo::{Bump, collections::Vec}; |
| //! |
| //! let b = Bump::new(); |
| //! |
| //! let v: Vec<i32> = bumpalo::vec![in &b]; |
| //! |
| //! let v = bumpalo::vec![in &b; 1, 2, 3, 4, 5]; |
| //! |
| //! let v = bumpalo::vec![in &b; 0; 10]; // ten zeroes |
| //! ``` |
| //! |
| //! You can [`push`] values onto the end of a vector (which will grow the vector |
| //! as needed): |
| //! |
| //! ``` |
| //! use bumpalo::{Bump, collections::Vec}; |
| //! |
| //! let b = Bump::new(); |
| //! |
| //! let mut v = bumpalo::vec![in &b; 1, 2]; |
| //! |
| //! v.push(3); |
| //! ``` |
| //! |
| //! Popping values works in much the same way: |
| //! |
| //! ``` |
| //! use bumpalo::{Bump, collections::Vec}; |
| //! |
| //! let b = Bump::new(); |
| //! |
| //! let mut v = bumpalo::vec![in &b; 1, 2]; |
| //! |
| //! let two = v.pop(); |
| //! ``` |
| //! |
| //! Vectors also support indexing (through the [`Index`] and [`IndexMut`] traits): |
| //! |
| //! ``` |
| //! use bumpalo::{Bump, collections::Vec}; |
| //! |
| //! let b = Bump::new(); |
| //! |
| //! let mut v = bumpalo::vec![in &b; 1, 2, 3]; |
| //! let three = v[2]; |
| //! v[1] = v[1] + 5; |
| //! ``` |
| //! |
| //! [`Vec<'bump, T>`]: ./struct.Vec.html |
| //! [`new`]: ./struct.Vec.html#method.new |
| //! [`push`]: ./struct.Vec.html#method.push |
| //! [`Index`]: https://doc.rust-lang.org/nightly/std/ops/trait.Index.html |
| //! [`IndexMut`]: ../../std/ops/trait.IndexMut.html |
| //! [`vec!`]: ../../macro.vec.html |
| |
| use super::raw_vec::RawVec; |
| use crate::Bump; |
| use core::cmp::Ordering; |
| use core::fmt; |
| use core::hash::{self, Hash}; |
| use core::iter::FusedIterator; |
| use core::marker::PhantomData; |
| use core::mem; |
| use core::ops; |
| use core::ops::Bound::{Excluded, Included, Unbounded}; |
| use core::ops::{Index, IndexMut, RangeBounds}; |
| use core::ptr; |
| use core::ptr::NonNull; |
| use core::slice; |
| |
| unsafe fn arith_offset<T>(p: *const T, offset: isize) -> *const T { |
| p.offset(offset) |
| } |
| |
| fn partition_dedup_by<T, F>(s: &mut [T], mut same_bucket: F) -> (&mut [T], &mut [T]) |
| where |
| F: FnMut(&mut T, &mut T) -> bool, |
| { |
| // Although we have a mutable reference to `s`, we cannot make |
| // *arbitrary* changes. The `same_bucket` calls could panic, so we |
| // must ensure that the slice is in a valid state at all times. |
| // |
| // The way that we handle this is by using swaps; we iterate |
| // over all the elements, swapping as we go so that at the end |
| // the elements we wish to keep are in the front, and those we |
| // wish to reject are at the back. We can then split the slice. |
| // This operation is still O(n). |
| // |
| // Example: We start in this state, where `r` represents "next |
| // read" and `w` represents "next_write`. |
| // |
| // r |
| // +---+---+---+---+---+---+ |
| // | 0 | 1 | 1 | 2 | 3 | 3 | |
| // +---+---+---+---+---+---+ |
| // w |
| // |
| // Comparing s[r] against s[w-1], this is not a duplicate, so |
| // we swap s[r] and s[w] (no effect as r==w) and then increment both |
| // r and w, leaving us with: |
| // |
| // r |
| // +---+---+---+---+---+---+ |
| // | 0 | 1 | 1 | 2 | 3 | 3 | |
| // +---+---+---+---+---+---+ |
| // w |
| // |
| // Comparing s[r] against s[w-1], this value is a duplicate, |
| // so we increment `r` but leave everything else unchanged: |
| // |
| // r |
| // +---+---+---+---+---+---+ |
| // | 0 | 1 | 1 | 2 | 3 | 3 | |
| // +---+---+---+---+---+---+ |
| // w |
| // |
| // Comparing s[r] against s[w-1], this is not a duplicate, |
| // so swap s[r] and s[w] and advance r and w: |
| // |
| // r |
| // +---+---+---+---+---+---+ |
| // | 0 | 1 | 2 | 1 | 3 | 3 | |
| // +---+---+---+---+---+---+ |
| // w |
| // |
| // Not a duplicate, repeat: |
| // |
| // r |
| // +---+---+---+---+---+---+ |
| // | 0 | 1 | 2 | 3 | 1 | 3 | |
| // +---+---+---+---+---+---+ |
| // w |
| // |
| // Duplicate, advance r. End of slice. Split at w. |
| |
| let len = s.len(); |
| if len <= 1 { |
| return (s, &mut []); |
| } |
| |
| let ptr = s.as_mut_ptr(); |
| let mut next_read: usize = 1; |
| let mut next_write: usize = 1; |
| |
| unsafe { |
| // Avoid bounds checks by using raw pointers. |
| while next_read < len { |
| let ptr_read = ptr.add(next_read); |
| let prev_ptr_write = ptr.add(next_write - 1); |
| if !same_bucket(&mut *ptr_read, &mut *prev_ptr_write) { |
| if next_read != next_write { |
| let ptr_write = prev_ptr_write.offset(1); |
| mem::swap(&mut *ptr_read, &mut *ptr_write); |
| } |
| next_write += 1; |
| } |
| next_read += 1; |
| } |
| } |
| |
| s.split_at_mut(next_write) |
| } |
| |
| unsafe fn offset_from<T>(p: *const T, origin: *const T) -> isize |
| where |
| T: Sized, |
| { |
| let pointee_size = mem::size_of::<T>(); |
| assert!(0 < pointee_size && pointee_size <= isize::max_value() as usize); |
| |
| // This is the same sequence that Clang emits for pointer subtraction. |
| // It can be neither `nsw` nor `nuw` because the input is treated as |
| // unsigned but then the output is treated as signed, so neither works. |
| let d = isize::wrapping_sub(p as _, origin as _); |
| d / (pointee_size as isize) |
| } |
| |
| /// Creates a [`Vec`] containing the arguments. |
| /// |
| /// `vec!` allows `Vec`s to be defined with the same syntax as array expressions. |
| /// There are two forms of this macro: |
| /// |
| /// - Create a [`Vec`] containing a given list of elements: |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, vec}; |
| /// |
| /// let b = Bump::new(); |
| /// let v = bumpalo::vec![in &b; 1, 2, 3]; |
| /// assert_eq!(v[0], 1); |
| /// assert_eq!(v[1], 2); |
| /// assert_eq!(v[2], 3); |
| /// ``` |
| /// |
| /// - Create a [`Vec`] from a given element and size: |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, vec}; |
| /// |
| /// let b = Bump::new(); |
| /// let v = bumpalo::vec![in &b; 1; 3]; |
| /// assert_eq!(v, [1, 1, 1]); |
| /// ``` |
| /// |
| /// Note that unlike array expressions this syntax supports all elements |
| /// which implement [`Clone`] and the number of elements doesn't have to be |
| /// a constant. |
| /// |
| /// This will use `clone` to duplicate an expression, so one should be careful |
| /// using this with types having a nonstandard `Clone` implementation. For |
| /// example, `bumpalo::vec![in ≎ Rc::new(1); 5]` will create a vector of five references |
| /// to the same boxed integer value, not five references pointing to independently |
| /// boxed integers. |
| /// |
| /// [`Vec`]: ../collections/vec/struct.Vec.html |
| /// [`Clone`]: https://doc.rust-lang.org/nightly/std/clone/trait.Clone.html |
| #[macro_export] |
| macro_rules! vec { |
| (in $bump:expr; $elem:expr; $n:expr) => {{ |
| let n = $n; |
| let mut v = $crate::collections::Vec::with_capacity_in(n, $bump); |
| if n > 0 { |
| let elem = $elem; |
| for _ in 0..n - 1 { |
| v.push(elem.clone()); |
| } |
| v.push(elem); |
| } |
| v |
| }}; |
| (in $bump:expr) => { $crate::collections::Vec::new_in($bump) }; |
| (in $bump:expr; $($x:expr),*) => {{ |
| let mut v = $crate::collections::Vec::new_in($bump); |
| $( v.push($x); )* |
| v |
| }}; |
| (in $bump:expr; $($x:expr,)*) => (bumpalo::vec![in $bump; $($x),*]) |
| } |
| |
| /// A contiguous growable array type, written `Vec<'bump, T>` but pronounced 'vector'. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// |
| /// let mut vec = Vec::new_in(&b); |
| /// 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]); |
| /// ``` |
| /// |
| /// The [`vec!`] macro is provided to make initialization more convenient: |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// |
| /// let mut vec = bumpalo::vec![in &b; 1, 2, 3]; |
| /// vec.push(4); |
| /// assert_eq!(vec, [1, 2, 3, 4]); |
| /// ``` |
| /// |
| /// It can also initialize each element of a `Vec<'bump, T>` with a given value. |
| /// This may be more efficient than performing allocation and initialization |
| /// in separate steps, especially when initializing a vector of zeros: |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// |
| /// let vec = bumpalo::vec![in &b; 0; 5]; |
| /// assert_eq!(vec, [0, 0, 0, 0, 0]); |
| /// |
| /// // The following is equivalent, but potentially slower: |
| /// let mut vec1 = Vec::with_capacity_in(5, &b); |
| /// vec1.resize(5, 0); |
| /// ``` |
| /// |
| /// Use a `Vec<'bump, T>` as an efficient stack: |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// |
| /// let mut stack = Vec::new_in(&b); |
| /// |
| /// stack.push(1); |
| /// stack.push(2); |
| /// stack.push(3); |
| /// |
| /// while let Some(top) = stack.pop() { |
| /// // Prints 3, 2, 1 |
| /// println!("{}", top); |
| /// } |
| /// ``` |
| /// |
| /// # Indexing |
| /// |
| /// The `Vec` type allows to access values by index, because it implements the |
| /// [`Index`] trait. An example will be more explicit: |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// |
| /// let v = bumpalo::vec![in &b; 0, 2, 4, 6]; |
| /// println!("{}", v[1]); // it will display '2' |
| /// ``` |
| /// |
| /// However be careful: if you try to access an index which isn't in the `Vec`, |
| /// your software will panic! You cannot do this: |
| /// |
| /// ```should_panic |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// |
| /// let v = bumpalo::vec![in &b; 0, 2, 4, 6]; |
| /// println!("{}", v[6]); // it will panic! |
| /// ``` |
| /// |
| /// In conclusion: always check if the index you want to get really exists |
| /// before doing it. |
| /// |
| /// # Slicing |
| /// |
| /// A `Vec` can be mutable. Slices, on the other hand, are read-only objects. |
| /// To get a slice, use `&`. Example: |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// fn read_slice(slice: &[usize]) { |
| /// // ... |
| /// } |
| /// |
| /// let b = Bump::new(); |
| /// |
| /// let v = bumpalo::vec![in &b; 0, 1]; |
| /// read_slice(&v); |
| /// |
| /// // ... and that's all! |
| /// // you can also do it like this: |
| /// let x : &[usize] = &v; |
| /// ``` |
| /// |
| /// In Rust, it's more common to pass slices as arguments rather than vectors |
| /// when you just want to provide a read access. The same goes for [`String`] and |
| /// [`&str`]. |
| /// |
| /// # Capacity and reallocation |
| /// |
| /// The capacity of a vector is the amount of space allocated for any future |
| /// elements that will be added onto the vector. This is not to be confused with |
| /// the *length* of a vector, which specifies the number of actual elements |
| /// within the vector. If a vector's length exceeds its capacity, its capacity |
| /// will automatically be increased, but its elements will have to be |
| /// reallocated. |
| /// |
| /// For example, a vector with capacity 10 and length 0 would be an empty vector |
| /// with space for 10 more elements. Pushing 10 or fewer elements onto the |
| /// vector will not change its capacity or cause reallocation to occur. However, |
| /// if the vector's length is increased to 11, it will have to reallocate, which |
| /// can be slow. For this reason, it is recommended to use [`Vec::with_capacity_in`] |
| /// whenever possible to specify how big the vector is expected to get. |
| /// |
| /// # Guarantees |
| /// |
| /// Due to its incredibly fundamental nature, `Vec` makes a lot of guarantees |
| /// about its design. This ensures that it's as low-overhead as possible in |
| /// the general case, and can be correctly manipulated in primitive ways |
| /// by unsafe code. Note that these guarantees refer to an unqualified `Vec<'bump, T>`. |
| /// If additional type parameters are added (e.g. to support custom allocators), |
| /// overriding their defaults may change the behavior. |
| /// |
| /// Most fundamentally, `Vec` is and always will be a (pointer, capacity, length) |
| /// triplet. No more, no less. The order of these fields is completely |
| /// unspecified, and you should use the appropriate methods to modify these. |
| /// The pointer will never be null, so this type is null-pointer-optimized. |
| /// |
| /// However, the pointer may not actually point to allocated memory. In particular, |
| /// if you construct a `Vec` with capacity 0 via [`Vec::new_in`], [`bumpalo::vec![in bump]`][`vec!`], |
| /// [`Vec::with_capacity_in(0)`][`Vec::with_capacity_in`], or by calling [`shrink_to_fit`] |
| /// on an empty Vec, it will not allocate memory. Similarly, if you store zero-sized |
| /// types inside a `Vec`, it will not allocate space for them. *Note that in this case |
| /// the `Vec` may not report a [`capacity`] of 0*. `Vec` will allocate if and only |
| /// if [`mem::size_of::<T>`]`() * capacity() > 0`. In general, `Vec`'s allocation |
| /// details are very subtle — if you intend to allocate memory using a `Vec` |
| /// and use it for something else (either to pass to unsafe code, or to build your |
| /// own memory-backed collection), be sure to deallocate this memory by using |
| /// `from_raw_parts` to recover the `Vec` and then dropping it. |
| /// |
| /// If a `Vec` *has* allocated memory, then the memory it points to is on the heap |
| /// (as defined by the allocator Rust is configured to use by default), and its |
| /// pointer points to [`len`] initialized, contiguous elements in order (what |
| /// you would see if you coerced it to a slice), followed by [`capacity`]` - |
| /// `[`len`] logically uninitialized, contiguous elements. |
| /// |
| /// `Vec` will never perform a "small optimization" where elements are actually |
| /// stored on the stack for two reasons: |
| /// |
| /// * It would make it more difficult for unsafe code to correctly manipulate |
| /// a `Vec`. The contents of a `Vec` wouldn't have a stable address if it were |
| /// only moved, and it would be more difficult to determine if a `Vec` had |
| /// actually allocated memory. |
| /// |
| /// * It would penalize the general case, incurring an additional branch |
| /// on every access. |
| /// |
| /// `Vec` will never automatically shrink itself, even if completely empty. This |
| /// ensures no unnecessary allocations or deallocations occur. Emptying a `Vec` |
| /// and then filling it back up to the same [`len`] should incur no calls to |
| /// the allocator. If you wish to free up unused memory, use |
| /// [`shrink_to_fit`][`shrink_to_fit`]. |
| /// |
| /// [`push`] and [`insert`] will never (re)allocate if the reported capacity is |
| /// sufficient. [`push`] and [`insert`] *will* (re)allocate if |
| /// [`len`]` == `[`capacity`]. That is, the reported capacity is completely |
| /// accurate, and can be relied on. It can even be used to manually free the memory |
| /// allocated by a `Vec` if desired. Bulk insertion methods *may* reallocate, even |
| /// when not necessary. |
| /// |
| /// `Vec` does not guarantee any particular growth strategy when reallocating |
| /// when full, nor when [`reserve`] is called. The current strategy is basic |
| /// and it may prove desirable to use a non-constant growth factor. Whatever |
| /// strategy is used will of course guarantee `O(1)` amortized [`push`]. |
| /// |
| /// `bumpalo::vec![in bump; x; n]`, `bumpalo::vec![in bump; a, b, c, d]`, and |
| /// [`Vec::with_capacity_in(n)`][`Vec::with_capacity_in`], will all produce a |
| /// `Vec` with exactly the requested capacity. If [`len`]` == `[`capacity`], (as |
| /// is the case for the [`vec!`] macro), then a `Vec<'bump, T>` can be converted |
| /// to and from a [`Box<[T]>`][owned slice] without reallocating or moving the |
| /// elements. |
| /// |
| /// `Vec` will not specifically overwrite any data that is removed from it, |
| /// but also won't specifically preserve it. Its uninitialized memory is |
| /// scratch space that it may use however it wants. It will generally just do |
| /// whatever is most efficient or otherwise easy to implement. Do not rely on |
| /// removed data to be erased for security purposes. Even if you drop a `Vec`, its |
| /// buffer may simply be reused by another `Vec`. Even if you zero a `Vec`'s memory |
| /// first, that may not actually happen because the optimizer does not consider |
| /// this a side-effect that must be preserved. There is one case which we will |
| /// not break, however: using `unsafe` code to write to the excess capacity, |
| /// and then increasing the length to match, is always valid. |
| /// |
| /// `Vec` does not currently guarantee the order in which elements are dropped. |
| /// The order has changed in the past and may change again. |
| /// |
| /// [`vec!`]: ../../macro.vec.html |
| /// [`Index`]: https://doc.rust-lang.org/nightly/std/ops/trait.Index.html |
| /// [`String`]: https://doc.rust-lang.org/nightly/std/string/struct.String.html |
| /// [`&str`]: https://doc.rust-lang.org/nightly/std/primitive.str.html |
| /// [`Vec::with_capacity_in`]: ./struct.Vec.html#method.with_capacity_in |
| /// [`Vec::new_in`]: ./struct.Vec.html#method.new |
| /// [`shrink_to_fit`]: ./struct.Vec.html#method.shrink_to_fit |
| /// [`capacity`]: ./struct.Vec.html#method.capacity |
| /// [`mem::size_of::<T>`]: https://doc.rust-lang.org/nightly/std/mem/fn.size_of.html |
| /// [`len`]: ./struct.Vec.html#method.len |
| /// [`push`]: ./struct.Vec.html#method.push |
| /// [`insert`]: ./struct.Vec.html#method.insert |
| /// [`reserve`]: ./struct.Vec.html#method.reserve |
| /// [owned slice]: https://doc.rust-lang.org/nightly/std/boxed/struct.Box.html |
| pub struct Vec<'bump, T: 'bump> { |
| buf: RawVec<'bump, T>, |
| len: usize, |
| } |
| |
| //////////////////////////////////////////////////////////////////////////////// |
| // Inherent methods |
| //////////////////////////////////////////////////////////////////////////////// |
| |
| impl<'bump, T: 'bump> Vec<'bump, T> { |
| /// Constructs a new, empty `Vec<'bump, T>`. |
| /// |
| /// The vector will not allocate until elements are pushed onto it. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// # #![allow(unused_mut)] |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// let mut vec: Vec<i32> = Vec::new_in(&b); |
| /// ``` |
| #[inline] |
| pub fn new_in(bump: &'bump Bump) -> Vec<'bump, T> { |
| Vec { |
| buf: RawVec::new_in(bump), |
| len: 0, |
| } |
| } |
| |
| /// Constructs a new, empty `Vec<'bump, T>` with the specified capacity. |
| /// |
| /// The vector will be able to hold exactly `capacity` elements without |
| /// reallocating. If `capacity` is 0, the vector will not allocate. |
| /// |
| /// It is important to note that although the returned vector has the |
| /// *capacity* specified, the vector will have a zero *length*. For an |
| /// explanation of the difference between length and capacity, see |
| /// *[Capacity and reallocation]*. |
| /// |
| /// [Capacity and reallocation]: #capacity-and-reallocation |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// |
| /// let mut vec = Vec::with_capacity_in(10, &b); |
| /// |
| /// // The vector contains no items, even though it has capacity for more |
| /// assert_eq!(vec.len(), 0); |
| /// |
| /// // These are all done without reallocating... |
| /// for i in 0..10 { |
| /// vec.push(i); |
| /// } |
| /// |
| /// // ...but this may make the vector reallocate |
| /// vec.push(11); |
| /// ``` |
| #[inline] |
| pub fn with_capacity_in(capacity: usize, bump: &'bump Bump) -> Vec<'bump, T> { |
| Vec { |
| buf: RawVec::with_capacity_in(capacity, bump), |
| len: 0, |
| } |
| } |
| |
| /// Construct a new `Vec` from the given iterator's items. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// use std::iter; |
| /// |
| /// let b = Bump::new(); |
| /// let v = Vec::from_iter_in(iter::repeat(7).take(3), &b); |
| /// assert_eq!(v, [7, 7, 7]); |
| /// ``` |
| pub fn from_iter_in<I: IntoIterator<Item = T>>(iter: I, bump: &'bump Bump) -> Vec<'bump, T> { |
| let mut v = Vec::new_in(bump); |
| v.extend(iter); |
| v |
| } |
| |
| /// Creates a `Vec<'bump, T>` directly from the raw components of another vector. |
| /// |
| /// # Safety |
| /// |
| /// This is highly unsafe, due to the number of invariants that aren't |
| /// checked: |
| /// |
| /// * `ptr` needs to have been previously allocated via [`String`]/`Vec<'bump, T>` |
| /// (at least, it's highly likely to be incorrect if it wasn't). |
| /// * `ptr`'s `T` needs to have the same size and alignment as it was allocated with. |
| /// * `length` needs to be less than or equal to `capacity`. |
| /// * `capacity` needs to be the capacity that the pointer was allocated with. |
| /// |
| /// Violating these may cause problems like corrupting the allocator's |
| /// internal data structures. For example it is **not** safe |
| /// to build a `Vec<u8>` from a pointer to a C `char` array and a `size_t`. |
| /// |
| /// The ownership of `ptr` is effectively transferred to the |
| /// `Vec<'bump, T>` which may then deallocate, reallocate or change the |
| /// contents of memory pointed to by the pointer at will. Ensure |
| /// that nothing else uses the pointer after calling this |
| /// function. |
| /// |
| /// [`String`]: https://doc.rust-lang.org/nightly/std/string/struct.String.html |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// use std::ptr; |
| /// use std::mem; |
| /// |
| /// let b = Bump::new(); |
| /// |
| /// let mut v = bumpalo::vec![in &b; 1, 2, 3]; |
| /// |
| /// // Pull out the various important pieces of information about `v` |
| /// let p = v.as_mut_ptr(); |
| /// let len = v.len(); |
| /// let cap = v.capacity(); |
| /// |
| /// unsafe { |
| /// // Cast `v` into the void: no destructor run, so we are in |
| /// // complete control of the allocation to which `p` points. |
| /// mem::forget(v); |
| /// |
| /// // Overwrite memory with 4, 5, 6 |
| /// for i in 0..len as isize { |
| /// ptr::write(p.offset(i), 4 + i); |
| /// } |
| /// |
| /// // Put everything back together into a Vec |
| /// let rebuilt = Vec::from_raw_parts_in(p, len, cap, &b); |
| /// assert_eq!(rebuilt, [4, 5, 6]); |
| /// } |
| /// ``` |
| pub unsafe fn from_raw_parts_in( |
| ptr: *mut T, |
| length: usize, |
| capacity: usize, |
| bump: &'bump Bump, |
| ) -> Vec<'bump, T> { |
| Vec { |
| buf: RawVec::from_raw_parts_in(ptr, capacity, bump), |
| len: length, |
| } |
| } |
| |
| /// Returns the number of elements the vector can hold without |
| /// reallocating. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// let vec: Vec<i32> = Vec::with_capacity_in(10, &b); |
| /// assert_eq!(vec.capacity(), 10); |
| /// ``` |
| #[inline] |
| pub fn capacity(&self) -> usize { |
| self.buf.cap() |
| } |
| |
| /// Reserves capacity for at least `additional` more elements to be inserted |
| /// in the given `Vec<'bump, T>`. The collection may reserve more space to avoid |
| /// frequent reallocations. After calling `reserve`, capacity will be |
| /// greater than or equal to `self.len() + additional`. Does nothing if |
| /// capacity is already sufficient. |
| /// |
| /// # Panics |
| /// |
| /// Panics if the new capacity overflows `usize`. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// let mut vec = bumpalo::vec![in &b; 1]; |
| /// vec.reserve(10); |
| /// assert!(vec.capacity() >= 11); |
| /// ``` |
| pub fn reserve(&mut self, additional: usize) { |
| self.buf.reserve(self.len, additional); |
| } |
| |
| /// Reserves the minimum capacity for exactly `additional` more elements to |
| /// be inserted in the given `Vec<'bump, T>`. After calling `reserve_exact`, |
| /// capacity will be greater than or equal to `self.len() + additional`. |
| /// Does nothing if the capacity is already sufficient. |
| /// |
| /// Note that the allocator may give the collection more space than it |
| /// requests. Therefore capacity can not be relied upon to be precisely |
| /// minimal. Prefer `reserve` if future insertions are expected. |
| /// |
| /// # Panics |
| /// |
| /// Panics if the new capacity overflows `usize`. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// let mut vec = bumpalo::vec![in &b; 1]; |
| /// vec.reserve_exact(10); |
| /// assert!(vec.capacity() >= 11); |
| /// ``` |
| pub fn reserve_exact(&mut self, additional: usize) { |
| self.buf.reserve_exact(self.len, additional); |
| } |
| |
| /// Shrinks the capacity of the vector as much as possible. |
| /// |
| /// It will drop down as close as possible to the length but the allocator |
| /// may still inform the vector that there is space for a few more elements. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// |
| /// let mut vec = Vec::with_capacity_in(10, &b); |
| /// vec.extend([1, 2, 3].iter().cloned()); |
| /// assert_eq!(vec.capacity(), 10); |
| /// vec.shrink_to_fit(); |
| /// assert!(vec.capacity() >= 3); |
| /// ``` |
| pub fn shrink_to_fit(&mut self) { |
| if self.capacity() != self.len { |
| self.buf.shrink_to_fit(self.len); |
| } |
| } |
| |
| /// Converts the vector into `&'bump [T]`. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// let v = bumpalo::vec![in &b; 1, 2, 3]; |
| /// |
| /// let slice = v.into_bump_slice(); |
| /// assert_eq!(slice, [1, 2, 3]); |
| /// ``` |
| pub fn into_bump_slice(self) -> &'bump [T] { |
| unsafe { |
| let ptr = self.as_ptr(); |
| let len = self.len(); |
| mem::forget(self); |
| slice::from_raw_parts(ptr, len) |
| } |
| } |
| |
| /// Converts the vector into `&'bump mut [T]`. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// let v = bumpalo::vec![in &b; 1, 2, 3]; |
| /// |
| /// let mut slice = v.into_bump_slice_mut(); |
| /// |
| /// slice[0] = 3; |
| /// slice[2] = 1; |
| /// |
| /// assert_eq!(slice, [3, 2, 1]); |
| /// ``` |
| pub fn into_bump_slice_mut(mut self) -> &'bump mut [T] { |
| let ptr = self.as_mut_ptr(); |
| let len = self.len(); |
| mem::forget(self); |
| |
| unsafe { |
| slice::from_raw_parts_mut(ptr, len) |
| } |
| } |
| |
| /// Shortens the vector, keeping the first `len` elements and dropping |
| /// the rest. |
| /// |
| /// If `len` is greater than the vector's current length, this has no |
| /// effect. |
| /// |
| /// The [`drain`] method can emulate `truncate`, but causes the excess |
| /// elements to be returned instead of dropped. |
| /// |
| /// Note that this method has no effect on the allocated capacity |
| /// of the vector. |
| /// |
| /// # Examples |
| /// |
| /// Truncating a five element vector to two elements: |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// |
| /// let mut vec = bumpalo::vec![in &b; 1, 2, 3, 4, 5]; |
| /// vec.truncate(2); |
| /// assert_eq!(vec, [1, 2]); |
| /// ``` |
| /// |
| /// No truncation occurs when `len` is greater than the vector's current |
| /// length: |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// |
| /// let mut vec = bumpalo::vec![in &b; 1, 2, 3]; |
| /// vec.truncate(8); |
| /// assert_eq!(vec, [1, 2, 3]); |
| /// ``` |
| /// |
| /// Truncating when `len == 0` is equivalent to calling the [`clear`] |
| /// method. |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// |
| /// let mut vec = bumpalo::vec![in &b; 1, 2, 3]; |
| /// vec.truncate(0); |
| /// assert_eq!(vec, []); |
| /// ``` |
| /// |
| /// [`clear`]: #method.clear |
| /// [`drain`]: #method.drain |
| pub fn truncate(&mut self, len: usize) { |
| let current_len = self.len; |
| unsafe { |
| let mut ptr = self.as_mut_ptr().add(self.len); |
| // Set the final length at the end, keeping in mind that |
| // dropping an element might panic. Works around a missed |
| // optimization, as seen in the following issue: |
| // https://github.com/rust-lang/rust/issues/51802 |
| let mut local_len = SetLenOnDrop::new(&mut self.len); |
| |
| // drop any extra elements |
| for _ in len..current_len { |
| local_len.decrement_len(1); |
| ptr = ptr.offset(-1); |
| ptr::drop_in_place(ptr); |
| } |
| } |
| } |
| |
| /// Extracts a slice containing the entire vector. |
| /// |
| /// Equivalent to `&s[..]`. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// use std::io::{self, Write}; |
| /// |
| /// let b = Bump::new(); |
| /// |
| /// let buffer = bumpalo::vec![in &b; 1, 2, 3, 5, 8]; |
| /// io::sink().write(buffer.as_slice()).unwrap(); |
| /// ``` |
| #[inline] |
| pub fn as_slice(&self) -> &[T] { |
| self |
| } |
| |
| /// Extracts a mutable slice of the entire vector. |
| /// |
| /// Equivalent to `&mut s[..]`. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// use std::io::{self, Read}; |
| /// |
| /// let b = Bump::new(); |
| /// let mut buffer = bumpalo::vec![in &b; 0; 3]; |
| /// io::repeat(0b101).read_exact(buffer.as_mut_slice()).unwrap(); |
| /// ``` |
| #[inline] |
| pub fn as_mut_slice(&mut self) -> &mut [T] { |
| self |
| } |
| |
| /// Sets the length of a vector. |
| /// |
| /// This will explicitly set the size of the vector, without actually |
| /// modifying its buffers, so it is up to the caller to ensure that the |
| /// vector is actually the specified size. |
| /// |
| /// # Safety |
| /// |
| /// - `new_len` must be less than or equal to [`capacity()`]. |
| /// - The elements at `old_len..new_len` must be initialized. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// use std::ptr; |
| /// |
| /// let b = Bump::new(); |
| /// |
| /// let mut vec = bumpalo::vec![in &b; 'r', 'u', 's', 't']; |
| /// |
| /// unsafe { |
| /// ptr::drop_in_place(&mut vec[3]); |
| /// vec.set_len(3); |
| /// } |
| /// assert_eq!(vec, ['r', 'u', 's']); |
| /// ``` |
| /// |
| /// In this example, there is a memory leak since the memory locations |
| /// owned by the inner vectors were not freed prior to the `set_len` call: |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// |
| /// let mut vec = bumpalo::vec![in &b; |
| /// bumpalo::vec![in &b; 1, 0, 0], |
| /// bumpalo::vec![in &b; 0, 1, 0], |
| /// bumpalo::vec![in &b; 0, 0, 1]]; |
| /// unsafe { |
| /// vec.set_len(0); |
| /// } |
| /// ``` |
| /// |
| /// In this example, the vector gets expanded from zero to four items |
| /// without any memory allocations occurring, resulting in vector |
| /// values of unallocated memory: |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// |
| /// let mut vec: Vec<char> = Vec::new_in(&b); |
| /// |
| /// unsafe { |
| /// vec.set_len(4); |
| /// } |
| /// ``` |
| #[inline] |
| pub unsafe fn set_len(&mut self, new_len: usize) { |
| 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 bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// |
| /// let mut v = bumpalo::vec![in &b; "foo", "bar", "baz", "qux"]; |
| /// |
| /// 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"]); |
| /// ``` |
| #[inline] |
| pub fn swap_remove(&mut self, index: usize) -> T { |
| unsafe { |
| // We replace self[index] with the last element. Note that if the |
| // bounds check on hole succeeds there must be a last element (which |
| // can be self[index] itself). |
| let hole: *mut T = &mut self[index]; |
| let last = ptr::read(self.get_unchecked(self.len - 1)); |
| self.len -= 1; |
| ptr::replace(hole, last) |
| } |
| } |
| |
| /// Inserts an element at position `index` within the vector, shifting all |
| /// elements after it to the right. |
| /// |
| /// # Panics |
| /// |
| /// Panics if `index > len`. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// |
| /// let mut vec = bumpalo::vec![in &b; 1, 2, 3]; |
| /// 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) { |
| let len = self.len(); |
| assert!(index <= len); |
| |
| // space for the new element |
| if len == self.buf.cap() { |
| self.reserve(1); |
| } |
| |
| 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); |
| } |
| } |
| |
| /// Removes and returns the element at position `index` within the vector, |
| /// shifting all elements after it to the left. |
| /// |
| /// # Panics |
| /// |
| /// Panics if `index` is out of bounds. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// |
| /// let mut v = bumpalo::vec![in &b; 1, 2, 3]; |
| /// assert_eq!(v.remove(1), 2); |
| /// assert_eq!(v, [1, 3]); |
| /// ``` |
| pub fn remove(&mut self, index: usize) -> T { |
| let len = self.len(); |
| assert!(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` such that `f(&e)` returns `false`. |
| /// This method operates in place and preserves the order of the retained |
| /// elements. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// |
| /// let mut vec = bumpalo::vec![in &b; 1, 2, 3, 4]; |
| /// vec.retain(|&x| x%2 == 0); |
| /// assert_eq!(vec, [2, 4]); |
| /// ``` |
| pub fn retain<F>(&mut self, mut f: F) |
| where |
| F: FnMut(&T) -> bool, |
| { |
| self.drain_filter(|x| !f(x)); |
| } |
| |
| fn drain_filter<'a, F>(&'a mut self, filter: F) -> DrainFilter<'a, 'bump, T, F> |
| where |
| F: FnMut(&mut T) -> bool, |
| { |
| let old_len = self.len(); |
| |
| // Guard against us getting leaked (leak amplification) |
| unsafe { |
| self.set_len(0); |
| } |
| |
| DrainFilter { |
| vec: self, |
| idx: 0, |
| del: 0, |
| old_len, |
| pred: filter, |
| } |
| } |
| |
| /// Removes all but the first of consecutive elements in the vector that resolve to the same |
| /// key. |
| /// |
| /// If the vector is sorted, this removes all duplicates. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// |
| /// let mut vec = bumpalo::vec![in &b; 10, 20, 21, 30, 20]; |
| /// |
| /// vec.dedup_by_key(|i| *i / 10); |
| /// |
| /// assert_eq!(vec, [10, 20, 30, 20]); |
| /// ``` |
| #[inline] |
| pub fn dedup_by_key<F, K>(&mut self, mut key: F) |
| where |
| F: FnMut(&mut T) -> K, |
| K: PartialEq, |
| { |
| self.dedup_by(|a, b| key(a) == key(b)) |
| } |
| |
| /// Removes all but the first of consecutive elements in the vector satisfying a given equality |
| /// relation. |
| /// |
| /// The `same_bucket` function is passed references to two elements from the vector and |
| /// must determine if the elements compare equal. The elements are passed in opposite order |
| /// from their order in the slice, so if `same_bucket(a, b)` returns `true`, `a` is removed. |
| /// |
| /// If the vector is sorted, this removes all duplicates. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// |
| /// let mut vec = bumpalo::vec![in &b; "foo", "bar", "Bar", "baz", "bar"]; |
| /// |
| /// vec.dedup_by(|a, b| a.eq_ignore_ascii_case(b)); |
| /// |
| /// assert_eq!(vec, ["foo", "bar", "baz", "bar"]); |
| /// ``` |
| pub fn dedup_by<F>(&mut self, same_bucket: F) |
| where |
| F: FnMut(&mut T, &mut T) -> bool, |
| { |
| let len = { |
| let (dedup, _) = partition_dedup_by(self.as_mut_slice(), same_bucket); |
| dedup.len() |
| }; |
| self.truncate(len); |
| } |
| |
| /// Appends an element to the back of a collection. |
| /// |
| /// # Panics |
| /// |
| /// Panics if the number of elements in the vector overflows a `usize`. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// |
| /// let mut vec = bumpalo::vec![in &b; 1, 2]; |
| /// vec.push(3); |
| /// assert_eq!(vec, [1, 2, 3]); |
| /// ``` |
| #[inline] |
| pub fn push(&mut self, value: T) { |
| // This will panic or abort if we would allocate > isize::MAX bytes |
| // or if the length increment would overflow for zero-sized types. |
| if self.len == self.buf.cap() { |
| self.reserve(1); |
| } |
| unsafe { |
| let end = self.as_mut_ptr().add(self.len); |
| ptr::write(end, value); |
| self.len += 1; |
| } |
| } |
| |
| /// Removes the last element from a vector and returns it, or [`None`] if it |
| /// is empty. |
| /// |
| /// [`None`]: https://doc.rust-lang.org/nightly/std/option/enum.Option.html#variant.None |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// |
| /// let mut vec = bumpalo::vec![in &b; 1, 2, 3]; |
| /// assert_eq!(vec.pop(), Some(3)); |
| /// assert_eq!(vec, [1, 2]); |
| /// ``` |
| #[inline] |
| pub fn pop(&mut self) -> Option<T> { |
| if self.len == 0 { |
| None |
| } else { |
| unsafe { |
| self.len -= 1; |
| Some(ptr::read(self.get_unchecked(self.len()))) |
| } |
| } |
| } |
| |
| /// Moves all the elements of `other` into `Self`, leaving `other` empty. |
| /// |
| /// # Panics |
| /// |
| /// Panics if the number of elements in the vector overflows a `usize`. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// |
| /// let mut vec = bumpalo::vec![in &b; 1, 2, 3]; |
| /// let mut vec2 = bumpalo::vec![in &b; 4, 5, 6]; |
| /// vec.append(&mut vec2); |
| /// assert_eq!(vec, [1, 2, 3, 4, 5, 6]); |
| /// assert_eq!(vec2, []); |
| /// ``` |
| #[inline] |
| pub fn append(&mut self, other: &mut Self) { |
| unsafe { |
| self.append_elements(other.as_slice() as _); |
| other.set_len(0); |
| } |
| } |
| |
| /// Appends elements to `Self` from other buffer. |
| #[inline] |
| unsafe fn append_elements(&mut self, other: *const [T]) { |
| let count = (*other).len(); |
| self.reserve(count); |
| let len = self.len(); |
| ptr::copy_nonoverlapping(other as *const T, self.get_unchecked_mut(len), count); |
| self.len += count; |
| } |
| |
| /// Creates a draining iterator that removes the specified range in the vector |
| /// and yields the removed items. |
| /// |
| /// Note 1: The element range is removed even if the iterator is only |
| /// partially consumed or not consumed at all. |
| /// |
| /// Note 2: It is unspecified how many elements are removed from the vector |
| /// if the `Drain` value is leaked. |
| /// |
| /// # Panics |
| /// |
| /// Panics if the starting point is greater than the end point or if |
| /// the end point is greater than the length of the vector. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// |
| /// let mut v = bumpalo::vec![in &b; 1, 2, 3]; |
| /// |
| /// let mut u: Vec<_> = Vec::new_in(&b); |
| /// u.extend(v.drain(1..)); |
| /// |
| /// assert_eq!(v, &[1]); |
| /// assert_eq!(u, &[2, 3]); |
| /// |
| /// // A full range clears the vector |
| /// v.drain(..); |
| /// assert_eq!(v, &[]); |
| /// ``` |
| pub fn drain<R>(&mut self, range: R) -> Drain<T> |
| where |
| R: RangeBounds<usize>, |
| { |
| // 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() { |
| Included(&n) => n, |
| Excluded(&n) => n + 1, |
| Unbounded => 0, |
| }; |
| let end = match range.end_bound() { |
| Included(&n) => n + 1, |
| Excluded(&n) => n, |
| Unbounded => len, |
| }; |
| assert!(start <= end); |
| assert!(end <= len); |
| |
| unsafe { |
| // set self.vec length's to start, to be safe in case Drain is leaked |
| self.set_len(start); |
| // Use the borrow in the IterMut to indicate borrowing behavior of the |
| // whole Drain iterator (like &mut T). |
| let range_slice = slice::from_raw_parts_mut(self.as_mut_ptr().add(start), end - start); |
| Drain { |
| tail_start: end, |
| tail_len: len - end, |
| iter: range_slice.iter(), |
| vec: NonNull::from(self), |
| } |
| } |
| } |
| |
| /// Clears the vector, removing all values. |
| /// |
| /// Note that this method has no effect on the allocated capacity |
| /// of the vector. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// |
| /// let mut v = bumpalo::vec![in &b; 1, 2, 3]; |
| /// |
| /// v.clear(); |
| /// |
| /// assert!(v.is_empty()); |
| /// ``` |
| #[inline] |
| pub fn clear(&mut self) { |
| self.truncate(0) |
| } |
| |
| /// Returns the number of elements in the vector, also referred to |
| /// as its 'length'. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// |
| /// let a = bumpalo::vec![in &b; 1, 2, 3]; |
| /// assert_eq!(a.len(), 3); |
| /// ``` |
| #[inline] |
| pub fn len(&self) -> usize { |
| self.len |
| } |
| |
| /// Returns `true` if the vector contains no elements. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// |
| /// let mut v = Vec::new_in(&b); |
| /// assert!(v.is_empty()); |
| /// |
| /// v.push(1); |
| /// assert!(!v.is_empty()); |
| /// ``` |
| pub fn is_empty(&self) -> bool { |
| self.len() == 0 |
| } |
| |
| /// Splits the collection into two at the given index. |
| /// |
| /// Returns a newly allocated `Self`. `self` contains elements `[0, at)`, |
| /// and the returned `Self` contains elements `[at, len)`. |
| /// |
| /// Note that the capacity of `self` does not change. |
| /// |
| /// # Panics |
| /// |
| /// Panics if `at > len`. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// |
| /// let mut vec = bumpalo::vec![in &b; 1,2,3]; |
| /// let vec2 = vec.split_off(1); |
| /// assert_eq!(vec, [1]); |
| /// assert_eq!(vec2, [2, 3]); |
| /// ``` |
| #[inline] |
| pub fn split_off(&mut self, at: usize) -> Self { |
| assert!(at <= self.len(), "`at` out of bounds"); |
| |
| let other_len = self.len - at; |
| let mut other = Vec::with_capacity_in(other_len, self.buf.bump()); |
| |
| // Unsafely `set_len` and copy items to `other`. |
| unsafe { |
| self.set_len(at); |
| other.set_len(other_len); |
| |
| ptr::copy_nonoverlapping(self.as_ptr().add(at), other.as_mut_ptr(), other.len()); |
| } |
| other |
| } |
| } |
| |
| impl<'bump, T: 'bump + Clone> Vec<'bump, T> { |
| /// 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. |
| /// |
| /// This method requires [`Clone`] to be able clone the passed value. If |
| /// you need more flexibility (or want to rely on [`Default`] instead of |
| /// [`Clone`]), use [`resize_with`]. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// |
| /// let mut vec = bumpalo::vec![in &b; "hello"]; |
| /// vec.resize(3, "world"); |
| /// assert_eq!(vec, ["hello", "world", "world"]); |
| /// |
| /// let mut vec = bumpalo::vec![in &b; 1, 2, 3, 4]; |
| /// vec.resize(2, 0); |
| /// assert_eq!(vec, [1, 2]); |
| /// ``` |
| /// |
| /// [`Clone`]: https://doc.rust-lang.org/nightly/std/clone/trait.Clone.html |
| /// [`Default`]: https://doc.rust-lang.org/nightly/std/default/trait.Default.html |
| /// [`resize_with`]: #method.resize_with |
| pub fn resize(&mut self, new_len: usize, value: T) { |
| let len = self.len(); |
| |
| if new_len > len { |
| self.extend_with(new_len - len, ExtendElement(value)) |
| } else { |
| self.truncate(new_len); |
| } |
| } |
| |
| /// 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. |
| /// |
| /// Note that this function is same as [`extend`] except that it is |
| /// specialized to work with slices instead. If and when Rust gets |
| /// specialization this function will likely be deprecated (but still |
| /// available). |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// |
| /// let mut vec = bumpalo::vec![in &b; 1]; |
| /// vec.extend_from_slice(&[2, 3, 4]); |
| /// assert_eq!(vec, [1, 2, 3, 4]); |
| /// ``` |
| /// |
| /// [`extend`]: #method.extend |
| pub fn extend_from_slice(&mut self, other: &[T]) { |
| self.extend(other.iter().cloned()) |
| } |
| } |
| |
| // This code generalises `extend_with_{element,default}`. |
| trait ExtendWith<T> { |
| fn next(&mut self) -> T; |
| fn last(self) -> T; |
| } |
| |
| struct ExtendElement<T>(T); |
| impl<T: Clone> ExtendWith<T> for ExtendElement<T> { |
| fn next(&mut self) -> T { |
| self.0.clone() |
| } |
| fn last(self) -> T { |
| self.0 |
| } |
| } |
| |
| impl<'bump, T: 'bump> Vec<'bump, T> { |
| /// Extend the vector by `n` values, using the given generator. |
| fn extend_with<E: ExtendWith<T>>(&mut self, n: usize, mut value: E) { |
| self.reserve(n); |
| |
| unsafe { |
| let mut ptr = self.as_mut_ptr().add(self.len()); |
| // Use SetLenOnDrop to work around bug where compiler |
| // may not realize the store through `ptr` through self.set_len() |
| // don't alias. |
| let mut local_len = SetLenOnDrop::new(&mut self.len); |
| |
| // Write all elements except the last one |
| for _ in 1..n { |
| ptr::write(ptr, value.next()); |
| ptr = ptr.offset(1); |
| // Increment the length in every step in case next() panics |
| local_len.increment_len(1); |
| } |
| |
| if n > 0 { |
| // We can write the last element directly without cloning needlessly |
| ptr::write(ptr, value.last()); |
| local_len.increment_len(1); |
| } |
| |
| // len set by scope guard |
| } |
| } |
| } |
| |
| // Set the length of the vec when the `SetLenOnDrop` value goes out of scope. |
| // |
| // The idea is: The length field in SetLenOnDrop is a local variable |
| // that the optimizer will see does not alias with any stores through the Vec's data |
| // pointer. This is a workaround for alias analysis issue #32155 |
| struct SetLenOnDrop<'a> { |
| len: &'a mut usize, |
| local_len: usize, |
| } |
| |
| impl<'a> SetLenOnDrop<'a> { |
| #[inline] |
| fn new(len: &'a mut usize) -> Self { |
| SetLenOnDrop { |
| local_len: *len, |
| len, |
| } |
| } |
| |
| #[inline] |
| fn increment_len(&mut self, increment: usize) { |
| self.local_len += increment; |
| } |
| |
| #[inline] |
| fn decrement_len(&mut self, decrement: usize) { |
| self.local_len -= decrement; |
| } |
| } |
| |
| impl<'a> Drop for SetLenOnDrop<'a> { |
| #[inline] |
| fn drop(&mut self) { |
| *self.len = self.local_len; |
| } |
| } |
| |
| impl<'bump, T: 'bump + PartialEq> Vec<'bump, T> { |
| /// Removes consecutive repeated elements in the vector according to the |
| /// [`PartialEq`] trait implementation. |
| /// |
| /// If the vector is sorted, this removes all duplicates. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// |
| /// let mut vec = bumpalo::vec![in &b; 1, 2, 2, 3, 2]; |
| /// |
| /// vec.dedup(); |
| /// |
| /// assert_eq!(vec, [1, 2, 3, 2]); |
| /// ``` |
| #[inline] |
| pub fn dedup(&mut self) { |
| self.dedup_by(|a, b| a == b) |
| } |
| } |
| |
| //////////////////////////////////////////////////////////////////////////////// |
| // Common trait implementations for Vec |
| //////////////////////////////////////////////////////////////////////////////// |
| |
| impl<'bump, T: 'bump + Clone> Clone for Vec<'bump, T> { |
| #[cfg(not(test))] |
| fn clone(&self) -> Vec<'bump, T> { |
| let mut v = Vec::with_capacity_in(self.len(), self.buf.bump()); |
| v.extend(self.iter().cloned()); |
| v |
| } |
| |
| // HACK(japaric): with cfg(test) the inherent `[T]::to_vec` method, which is |
| // required for this method definition, is not available. Instead use the |
| // `slice::to_vec` function which is only available with cfg(test) |
| // NB see the slice::hack module in slice.rs for more information |
| #[cfg(test)] |
| fn clone(&self) -> Vec<'bump, T> { |
| let mut v = Vec::new_in(self.buf.bump()); |
| v.extend(self.iter().cloned()); |
| v |
| } |
| } |
| |
| impl<'bump, T: 'bump + Hash> Hash for Vec<'bump, T> { |
| #[inline] |
| fn hash<H: hash::Hasher>(&self, state: &mut H) { |
| Hash::hash(&**self, state) |
| } |
| } |
| |
| impl<'bump, T, I> Index<I> for Vec<'bump, T> |
| where |
| I: ::core::slice::SliceIndex<[T]>, |
| { |
| type Output = I::Output; |
| |
| #[inline] |
| fn index(&self, index: I) -> &Self::Output { |
| Index::index(&**self, index) |
| } |
| } |
| |
| impl<'bump, T, I> IndexMut<I> for Vec<'bump, T> |
| where |
| I: ::core::slice::SliceIndex<[T]>, |
| { |
| #[inline] |
| fn index_mut(&mut self, index: I) -> &mut Self::Output { |
| IndexMut::index_mut(&mut **self, index) |
| } |
| } |
| |
| impl<'bump, T: 'bump> ops::Deref for Vec<'bump, T> { |
| type Target = [T]; |
| |
| fn deref(&self) -> &[T] { |
| unsafe { |
| let p = self.buf.ptr(); |
| // assume(!p.is_null()); |
| slice::from_raw_parts(p, self.len) |
| } |
| } |
| } |
| |
| impl<'bump, T: 'bump> ops::DerefMut for Vec<'bump, T> { |
| fn deref_mut(&mut self) -> &mut [T] { |
| unsafe { |
| let ptr = self.buf.ptr(); |
| // assume(!ptr.is_null()); |
| slice::from_raw_parts_mut(ptr, self.len) |
| } |
| } |
| } |
| |
| impl<'bump, T: 'bump> IntoIterator for Vec<'bump, T> { |
| type Item = T; |
| type IntoIter = IntoIter<T>; |
| |
| /// Creates a consuming iterator, that is, one that moves each value out of |
| /// the vector (from start to end). The vector cannot be used after calling |
| /// this. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// |
| /// let v = bumpalo::vec![in &b; "a".to_string(), "b".to_string()]; |
| /// for s in v.into_iter() { |
| /// // s has type String, not &String |
| /// println!("{}", s); |
| /// } |
| /// ``` |
| #[inline] |
| fn into_iter(mut self) -> IntoIter<T> { |
| unsafe { |
| let begin = self.as_mut_ptr(); |
| // assume(!begin.is_null()); |
| let end = if mem::size_of::<T>() == 0 { |
| arith_offset(begin as *const i8, self.len() as isize) as *const T |
| } else { |
| begin.add(self.len()) as *const T |
| }; |
| mem::forget(self); |
| IntoIter { |
| phantom: PhantomData, |
| ptr: begin, |
| end, |
| } |
| } |
| } |
| } |
| |
| impl<'a, 'bump, T> IntoIterator for &'a Vec<'bump, T> { |
| type Item = &'a T; |
| type IntoIter = slice::Iter<'a, T>; |
| |
| fn into_iter(self) -> slice::Iter<'a, T> { |
| self.iter() |
| } |
| } |
| |
| impl<'a, 'bump, T> IntoIterator for &'a mut Vec<'bump, T> { |
| type Item = &'a mut T; |
| type IntoIter = slice::IterMut<'a, T>; |
| |
| fn into_iter(self) -> slice::IterMut<'a, T> { |
| self.iter_mut() |
| } |
| } |
| |
| impl<'bump, T: 'bump> Extend<T> for Vec<'bump, T> { |
| #[inline] |
| fn extend<I: IntoIterator<Item = T>>(&mut self, iter: I) { |
| let iter = iter.into_iter(); |
| self.reserve(iter.size_hint().0); |
| |
| for t in iter { |
| self.push(t); |
| } |
| } |
| } |
| |
| impl<'bump, T: 'bump> Vec<'bump, T> { |
| /// Creates a splicing iterator that replaces the specified range in the vector |
| /// with the given `replace_with` iterator and yields the removed items. |
| /// `replace_with` does not need to be the same length as `range`. |
| /// |
| /// Note 1: The element range is removed even if the iterator is not |
| /// consumed until the end. |
| /// |
| /// Note 2: It is unspecified how many elements are removed from the vector, |
| /// if the `Splice` value is leaked. |
| /// |
| /// Note 3: The input iterator `replace_with` is only consumed |
| /// when the `Splice` value is dropped. |
| /// |
| /// Note 4: This is optimal if: |
| /// |
| /// * The tail (elements in the vector after `range`) is empty, |
| /// * or `replace_with` yields fewer elements than `range`’s length |
| /// * or the lower bound of its `size_hint()` is exact. |
| /// |
| /// Otherwise, a temporary vector is allocated and the tail is moved twice. |
| /// |
| /// # Panics |
| /// |
| /// Panics if the starting point is greater than the end point or if |
| /// the end point is greater than the length of the vector. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// |
| /// let mut v = bumpalo::vec![in &b; 1, 2, 3]; |
| /// let new = [7, 8]; |
| /// let u: Vec<_> = Vec::from_iter_in(v.splice(..2, new.iter().cloned()), &b); |
| /// assert_eq!(v, &[7, 8, 3]); |
| /// assert_eq!(u, &[1, 2]); |
| /// ``` |
| #[inline] |
| pub fn splice<R, I>(&mut self, range: R, replace_with: I) -> Splice<I::IntoIter> |
| where |
| R: RangeBounds<usize>, |
| I: IntoIterator<Item = T>, |
| { |
| Splice { |
| drain: self.drain(range), |
| replace_with: replace_with.into_iter(), |
| } |
| } |
| } |
| |
| /// Extend implementation that copies elements out of references before pushing them onto the Vec. |
| /// |
| /// This implementation is specialized for slice iterators, where it uses [`copy_from_slice`] to |
| /// append the entire slice at once. |
| /// |
| /// [`copy_from_slice`]: https://doc.rust-lang.org/nightly/std/primitive.slice.html#method.copy_from_slice |
| impl<'a, 'bump, T: 'a + Copy> Extend<&'a T> for Vec<'bump, T> { |
| fn extend<I: IntoIterator<Item = &'a T>>(&mut self, iter: I) { |
| self.extend(iter.into_iter().cloned()) |
| } |
| } |
| |
| macro_rules! __impl_slice_eq1 { |
| ($Lhs: ty, $Rhs: ty) => { |
| __impl_slice_eq1! { $Lhs, $Rhs, Sized } |
| }; |
| ($Lhs: ty, $Rhs: ty, $Bound: ident) => { |
| impl<'a, 'b, A: $Bound, B> PartialEq<$Rhs> for $Lhs |
| where |
| A: PartialEq<B>, |
| { |
| #[inline] |
| fn eq(&self, other: &$Rhs) -> bool { |
| self[..] == other[..] |
| } |
| } |
| }; |
| } |
| |
| __impl_slice_eq1! { Vec<'a, A>, Vec<'b, B> } |
| __impl_slice_eq1! { Vec<'a, A>, &'b [B] } |
| __impl_slice_eq1! { Vec<'a, A>, &'b mut [B] } |
| // __impl_slice_eq1! { Cow<'a, [A]>, Vec<'b, B>, Clone } |
| |
| macro_rules! array_impls { |
| ($($N: expr)+) => { |
| $( |
| // NOTE: some less important impls are omitted to reduce code bloat |
| __impl_slice_eq1! { Vec<'a, A>, [B; $N] } |
| __impl_slice_eq1! { Vec<'a, A>, &'b [B; $N] } |
| // __impl_slice_eq1! { Vec<A>, &'b mut [B; $N] } |
| // __impl_slice_eq1! { Cow<'a, [A]>, [B; $N], Clone } |
| // __impl_slice_eq1! { Cow<'a, [A]>, &'b [B; $N], Clone } |
| // __impl_slice_eq1! { Cow<'a, [A]>, &'b mut [B; $N], Clone } |
| )+ |
| } |
| } |
| |
| array_impls! { |
| 0 1 2 3 4 5 6 7 8 9 |
| 10 11 12 13 14 15 16 17 18 19 |
| 20 21 22 23 24 25 26 27 28 29 |
| 30 31 32 |
| } |
| |
| /// Implements comparison of vectors, lexicographically. |
| impl<'bump, T: 'bump + PartialOrd> PartialOrd for Vec<'bump, T> { |
| #[inline] |
| fn partial_cmp(&self, other: &Vec<'bump, T>) -> Option<Ordering> { |
| PartialOrd::partial_cmp(&**self, &**other) |
| } |
| } |
| |
| impl<'bump, T: 'bump + Eq> Eq for Vec<'bump, T> {} |
| |
| /// Implements ordering of vectors, lexicographically. |
| impl<'bump, T: 'bump + Ord> Ord for Vec<'bump, T> { |
| #[inline] |
| fn cmp(&self, other: &Vec<'bump, T>) -> Ordering { |
| Ord::cmp(&**self, &**other) |
| } |
| } |
| |
| impl<'bump, T: 'bump + fmt::Debug> fmt::Debug for Vec<'bump, T> { |
| fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { |
| fmt::Debug::fmt(&**self, f) |
| } |
| } |
| |
| impl<'bump, T: 'bump> AsRef<Vec<'bump, T>> for Vec<'bump, T> { |
| fn as_ref(&self) -> &Vec<'bump, T> { |
| self |
| } |
| } |
| |
| impl<'bump, T: 'bump> AsMut<Vec<'bump, T>> for Vec<'bump, T> { |
| fn as_mut(&mut self) -> &mut Vec<'bump, T> { |
| self |
| } |
| } |
| |
| impl<'bump, T: 'bump> AsRef<[T]> for Vec<'bump, T> { |
| fn as_ref(&self) -> &[T] { |
| self |
| } |
| } |
| |
| impl<'bump, T: 'bump> AsMut<[T]> for Vec<'bump, T> { |
| fn as_mut(&mut self) -> &mut [T] { |
| self |
| } |
| } |
| |
| // // note: test pulls in libstd, which causes errors here |
| // #[cfg(not(test))] |
| // impl<'bump, T: 'bump> From<Vec<'bump, T>> for Box<[T]> { |
| // fn from(v: Vec<'bump, T>) -> Box<[T]> { |
| // v.into_boxed_slice() |
| // } |
| // } |
| |
| //////////////////////////////////////////////////////////////////////////////// |
| // Clone-on-write |
| //////////////////////////////////////////////////////////////////////////////// |
| |
| // impl<'a, 'bump, T: Clone> From<Vec<'bump, T>> for Cow<'a, [T]> { |
| // fn from(v: Vec<'bump, T>) -> Cow<'a, [T]> { |
| // Cow::Owned(v) |
| // } |
| // } |
| |
| // impl<'a, 'bump, T: Clone> From<&'a Vec<'bump, T>> for Cow<'a, [T]> { |
| // fn from(v: &'a Vec<'bump, T>) -> Cow<'a, [T]> { |
| // Cow::Borrowed(v.as_slice()) |
| // } |
| // } |
| |
| //////////////////////////////////////////////////////////////////////////////// |
| // Iterators |
| //////////////////////////////////////////////////////////////////////////////// |
| |
| /// An iterator that moves out of a vector. |
| /// |
| /// This `struct` is created by the `into_iter` method on [`Vec`][`Vec`] (provided |
| /// by the [`IntoIterator`] trait). |
| /// |
| /// [`Vec`]: struct.Vec.html |
| /// [`IntoIterator`]: https://doc.rust-lang.org/nightly/std/iter/trait.IntoIterator.html |
| pub struct IntoIter<T> { |
| phantom: PhantomData<T>, |
| ptr: *const T, |
| end: *const T, |
| } |
| |
| impl<T: fmt::Debug> fmt::Debug for IntoIter<T> { |
| fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { |
| f.debug_tuple("IntoIter").field(&self.as_slice()).finish() |
| } |
| } |
| |
| impl<'bump, T: 'bump> IntoIter<T> { |
| /// Returns the remaining items of this iterator as a slice. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// |
| /// let vec = bumpalo::vec![in &b; 'a', 'b', 'c']; |
| /// let mut into_iter = vec.into_iter(); |
| /// assert_eq!(into_iter.as_slice(), &['a', 'b', 'c']); |
| /// let _ = into_iter.next().unwrap(); |
| /// assert_eq!(into_iter.as_slice(), &['b', 'c']); |
| /// ``` |
| pub fn as_slice(&self) -> &[T] { |
| unsafe { slice::from_raw_parts(self.ptr, self.len()) } |
| } |
| |
| /// Returns the remaining items of this iterator as a mutable slice. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use bumpalo::{Bump, collections::Vec}; |
| /// |
| /// let b = Bump::new(); |
| /// |
| /// let vec = bumpalo::vec![in &b; 'a', 'b', 'c']; |
| /// let mut into_iter = vec.into_iter(); |
| /// assert_eq!(into_iter.as_slice(), &['a', 'b', 'c']); |
| /// into_iter.as_mut_slice()[2] = 'z'; |
| /// assert_eq!(into_iter.next().unwrap(), 'a'); |
| /// assert_eq!(into_iter.next().unwrap(), 'b'); |
| /// assert_eq!(into_iter.next().unwrap(), 'z'); |
| /// ``` |
| pub fn as_mut_slice(&mut self) -> &mut [T] { |
| unsafe { slice::from_raw_parts_mut(self.ptr as *mut T, self.len()) } |
| } |
| } |
| |
| unsafe impl<T: Send> Send for IntoIter<T> {} |
| unsafe impl<T: Sync> Sync for IntoIter<T> {} |
| |
| impl<'bump, T: 'bump> Iterator for IntoIter<T> { |
| type Item = T; |
| |
| #[inline] |
| fn next(&mut self) -> Option<T> { |
| unsafe { |
| if self.ptr as *const _ == self.end { |
| None |
| } else if mem::size_of::<T>() == 0 { |
| // purposefully don't use 'ptr.offset' because for |
| // vectors with 0-size elements this would return the |
| // same pointer. |
| self.ptr = arith_offset(self.ptr as *const i8, 1) as *mut T; |
| |
| // Make up a value of this ZST. |
| Some(mem::zeroed()) |
| } else { |
| let old = self.ptr; |
| self.ptr = self.ptr.offset(1); |
| |
| Some(ptr::read(old)) |
| } |
| } |
| } |
| |
| #[inline] |
| fn size_hint(&self) -> (usize, Option<usize>) { |
| let exact = if mem::size_of::<T>() == 0 { |
| (self.end as usize).wrapping_sub(self.ptr as usize) |
| } else { |
| unsafe { offset_from(self.end, self.ptr) as usize } |
| }; |
| (exact, Some(exact)) |
| } |
| |
| #[inline] |
| fn count(self) -> usize { |
| self.len() |
| } |
| } |
| |
| impl<'bump, T: 'bump> DoubleEndedIterator for IntoIter<T> { |
| #[inline] |
| fn next_back(&mut self) -> Option<T> { |
| unsafe { |
| if self.end == self.ptr { |
| None |
| } else if mem::size_of::<T>() == 0 { |
| // See above for why 'ptr.offset' isn't used |
| self.end = arith_offset(self.end as *const i8, -1) as *mut T; |
| |
| // Make up a value of this ZST. |
| Some(mem::zeroed()) |
| } else { |
| self.end = self.end.offset(-1); |
| |
| Some(ptr::read(self.end)) |
| } |
| } |
| } |
| } |
| |
| impl<'bump, T: 'bump> ExactSizeIterator for IntoIter<T> {} |
| |
| impl<'bump, T: 'bump> FusedIterator for IntoIter<T> {} |
| |
| /// A draining iterator for `Vec<'bump, T>`. |
| /// |
| /// This `struct` is created by the [`drain`] method on [`Vec`]. |
| /// |
| /// [`drain`]: struct.Vec.html#method.drain |
| /// [`Vec`]: struct.Vec.html |
| pub struct Drain<'a, 'bump, T: 'a + 'bump> { |
| /// 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: NonNull<Vec<'bump, T>>, |
| } |
| |
| impl<'a, 'bump, T: 'a + 'bump + fmt::Debug> fmt::Debug for Drain<'a, 'bump, T> { |
| fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { |
| f.debug_tuple("Drain").field(&self.iter.as_slice()).finish() |
| } |
| } |
| |
| unsafe impl<'a, 'bump, T: Sync> Sync for Drain<'a, 'bump, T> {} |
| unsafe impl<'a, 'bump, T: Send> Send for Drain<'a, 'bump, T> {} |
| |
| impl<'a, 'bump, T> Iterator for Drain<'a, 'bump, T> { |
| type Item = T; |
| |
| #[inline] |
| fn next(&mut self) -> Option<T> { |
| self.iter |
| .next() |
| .map(|elt| unsafe { ptr::read(elt as *const _) }) |
| } |
| |
| fn size_hint(&self) -> (usize, Option<usize>) { |
| self.iter.size_hint() |
| } |
| } |
| |
| impl<'a, 'bump, T> DoubleEndedIterator for Drain<'a, 'bump, T> { |
| #[inline] |
| fn next_back(&mut self) -> Option<T> { |
| self.iter |
| .next_back() |
| .map(|elt| unsafe { ptr::read(elt as *const _) }) |
| } |
| } |
| |
| impl<'a, 'bump, T> Drop for Drain<'a, 'bump, T> { |
| fn drop(&mut self) { |
| // exhaust self first |
| self.for_each(drop); |
| |
| if self.tail_len > 0 { |
| unsafe { |
| let source_vec = self.vec.as_mut(); |
| // memmove back untouched tail, update to new length |
| let start = source_vec.len(); |
| let tail = self.tail_start; |
| if tail != start { |
| let src = source_vec.as_ptr().add(tail); |
| let dst = source_vec.as_mut_ptr().add(start); |
| ptr::copy(src, dst, self.tail_len); |
| } |
| source_vec.set_len(start + self.tail_len); |
| } |
| } |
| } |
| } |
| |
| impl<'a, 'bump, T> ExactSizeIterator for Drain<'a, 'bump, T> {} |
| |
| impl<'a, 'bump, T> FusedIterator for Drain<'a, 'bump, T> {} |
| |
| /// A splicing iterator for `Vec`. |
| /// |
| /// This struct is created by the [`splice()`] method on [`Vec`]. See its |
| /// documentation for more. |
| /// |
| /// [`splice()`]: struct.Vec.html#method.splice |
| /// [`Vec`]: struct.Vec.html |
| #[derive(Debug)] |
| pub struct Splice<'a, 'bump, I: Iterator + 'a + 'bump> { |
| drain: Drain<'a, 'bump, I::Item>, |
| replace_with: I, |
| } |
| |
| impl<'a, 'bump, I: Iterator> Iterator for Splice<'a, 'bump, I> { |
| type Item = I::Item; |
| |
| fn next(&mut self) -> Option<Self::Item> { |
| self.drain.next() |
| } |
| |
| fn size_hint(&self) -> (usize, Option<usize>) { |
| self.drain.size_hint() |
| } |
| } |
| |
| impl<'a, 'bump, I: Iterator> DoubleEndedIterator for Splice<'a, 'bump, I> { |
| fn next_back(&mut self) -> Option<Self::Item> { |
| self.drain.next_back() |
| } |
| } |
| |
| impl<'a, 'bump, I: Iterator> ExactSizeIterator for Splice<'a, 'bump, I> {} |
| |
| impl<'a, 'bump, I: Iterator> Drop for Splice<'a, 'bump, I> { |
| fn drop(&mut self) { |
| self.drain.by_ref().for_each(drop); |
| |
| unsafe { |
| if self.drain.tail_len == 0 { |
| self.drain.vec.as_mut().extend(self.replace_with.by_ref()); |
| return; |
| } |
| |
| // First fill the range left by drain(). |
| if !self.drain.fill(&mut self.replace_with) { |
| return; |
| } |
| |
| // There may be more elements. Use the lower bound as an estimate. |
| // FIXME: Is the upper bound a better guess? Or something else? |
| let (lower_bound, _upper_bound) = self.replace_with.size_hint(); |
| if lower_bound > 0 { |
| self.drain.move_tail(lower_bound); |
| if !self.drain.fill(&mut self.replace_with) { |
| return; |
| } |
| } |
| |
| // Collect any remaining elements. |
| // This is a zero-length vector which does not allocate if `lower_bound` was exact. |
| let mut collected = Vec::new_in(self.drain.vec.as_ref().buf.bump()); |
| collected.extend(self.replace_with.by_ref()); |
| let mut collected = collected.into_iter(); |
| // Now we have an exact count. |
| if collected.len() > 0 { |
| self.drain.move_tail(collected.len()); |
| let filled = self.drain.fill(&mut collected); |
| debug_assert!(filled); |
| debug_assert_eq!(collected.len(), 0); |
| } |
| } |
| // Let `Drain::drop` move the tail back if necessary and restore `vec.len`. |
| } |
| } |
| |
| /// Private helper methods for `Splice::drop` |
| impl<'a, 'bump, T> Drain<'a, 'bump, T> { |
| /// The range from `self.vec.len` to `self.tail_start` contains elements |
| /// that have been moved out. |
| /// Fill that range as much as possible with new elements from the `replace_with` iterator. |
| /// Return whether we filled the entire range. (`replace_with.next()` didn’t return `None`.) |
| unsafe fn fill<I: Iterator<Item = T>>(&mut self, replace_with: &mut I) -> bool { |
| let vec = self.vec.as_mut(); |
| let range_start = vec.len; |
| let range_end = self.tail_start; |
| let range_slice = |
| slice::from_raw_parts_mut(vec.as_mut_ptr().add(range_start), range_end - range_start); |
| |
| for place in range_slice { |
| if let Some(new_item) = replace_with.next() { |
| ptr::write(place, new_item); |
| vec.len += 1; |
| } else { |
| return false; |
| } |
| } |
| true |
| } |
| |
| /// Make room for inserting more elements before the tail. |
| unsafe fn move_tail(&mut self, extra_capacity: usize) { |
| let vec = self.vec.as_mut(); |
| let used_capacity = self.tail_start + self.tail_len; |
| vec.buf.reserve(used_capacity, extra_capacity); |
| |
| let new_tail_start = self.tail_start + extra_capacity; |
| let src = vec.as_ptr().add(self.tail_start); |
| let dst = vec.as_mut_ptr().add(new_tail_start); |
| ptr::copy(src, dst, self.tail_len); |
| self.tail_start = new_tail_start; |
| } |
| } |
| |
| /// An iterator produced by calling `drain_filter` on Vec. |
| #[derive(Debug)] |
| pub struct DrainFilter<'a, 'bump: 'a, T: 'a + 'bump, F> |
| where |
| F: FnMut(&mut T) -> bool, |
| { |
| vec: &'a mut Vec<'bump, T>, |
| idx: usize, |
| del: usize, |
| old_len: usize, |
| pred: F, |
| } |
| |
| impl<'a, 'bump, T, F> Iterator for DrainFilter<'a, 'bump, T, F> |
| where |
| F: FnMut(&mut T) -> bool, |
| { |
| type Item = T; |
| |
| fn next(&mut self) -> Option<T> { |
| unsafe { |
| while self.idx != self.old_len { |
| let i = self.idx; |
| self.idx += 1; |
| let v = slice::from_raw_parts_mut(self.vec.as_mut_ptr(), self.old_len); |
| if (self.pred)(&mut v[i]) { |
| self.del += 1; |
| return Some(ptr::read(&v[i])); |
| } else if self.del > 0 { |
| let del = self.del; |
| let src: *const T = &v[i]; |
| let dst: *mut T = &mut v[i - del]; |
| // This is safe because self.vec has length 0 |
| // thus its elements will not have Drop::drop |
| // called on them in the event of a panic. |
| ptr::copy_nonoverlapping(src, dst, 1); |
| } |
| } |
| None |
| } |
| } |
| |
| fn size_hint(&self) -> (usize, Option<usize>) { |
| (0, Some(self.old_len - self.idx)) |
| } |
| } |
| |
| impl<'a, 'bump, T, F> Drop for DrainFilter<'a, 'bump, T, F> |
| where |
| F: FnMut(&mut T) -> bool, |
| { |
| fn drop(&mut self) { |
| self.for_each(drop); |
| unsafe { |
| self.vec.set_len(self.old_len - self.del); |
| } |
| } |
| } |
