+++ /dev/null
-// SPDX-License-Identifier: Apache-2.0 OR MIT
-
-#[cfg(not(no_global_oom_handling))]
-use super::AsVecIntoIter;
-use crate::alloc::{Allocator, Global};
-#[cfg(not(no_global_oom_handling))]
-use crate::collections::VecDeque;
-use crate::raw_vec::RawVec;
-use core::array;
-use core::fmt;
-use core::iter::{
- FusedIterator, InPlaceIterable, SourceIter, TrustedFused, TrustedLen,
- TrustedRandomAccessNoCoerce,
-};
-use core::marker::PhantomData;
-use core::mem::{self, ManuallyDrop, MaybeUninit, SizedTypeProperties};
-use core::num::NonZeroUsize;
-#[cfg(not(no_global_oom_handling))]
-use core::ops::Deref;
-use core::ptr::{self, NonNull};
-use core::slice::{self};
-
-/// An iterator that moves out of a vector.
-///
-/// This `struct` is created by the `into_iter` method on [`Vec`](super::Vec)
-/// (provided by the [`IntoIterator`] trait).
-///
-/// # Example
-///
-/// ```
-/// let v = vec![0, 1, 2];
-/// let iter: std::vec::IntoIter<_> = v.into_iter();
-/// ```
-#[stable(feature = "rust1", since = "1.0.0")]
-#[rustc_insignificant_dtor]
-pub struct IntoIter<
- T,
- #[unstable(feature = "allocator_api", issue = "32838")] A: Allocator = Global,
-> {
- pub(super) buf: NonNull<T>,
- pub(super) phantom: PhantomData<T>,
- pub(super) cap: usize,
- // the drop impl reconstructs a RawVec from buf, cap and alloc
- // to avoid dropping the allocator twice we need to wrap it into ManuallyDrop
- pub(super) alloc: ManuallyDrop<A>,
- pub(super) ptr: *const T,
- pub(super) end: *const T, // If T is a ZST, this is actually ptr+len. This encoding is picked so that
- // ptr == end is a quick test for the Iterator being empty, that works
- // for both ZST and non-ZST.
-}
-
-#[stable(feature = "vec_intoiter_debug", since = "1.13.0")]
-impl<T: fmt::Debug, A: Allocator> fmt::Debug for IntoIter<T, A> {
- fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
- f.debug_tuple("IntoIter").field(&self.as_slice()).finish()
- }
-}
-
-impl<T, A: Allocator> IntoIter<T, A> {
- /// Returns the remaining items of this iterator as a slice.
- ///
- /// # Examples
- ///
- /// ```
- /// let vec = vec!['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']);
- /// ```
- #[stable(feature = "vec_into_iter_as_slice", since = "1.15.0")]
- 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
- ///
- /// ```
- /// let vec = vec!['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');
- /// ```
- #[stable(feature = "vec_into_iter_as_slice", since = "1.15.0")]
- pub fn as_mut_slice(&mut self) -> &mut [T] {
- unsafe { &mut *self.as_raw_mut_slice() }
- }
-
- /// Returns a reference to the underlying allocator.
- #[unstable(feature = "allocator_api", issue = "32838")]
- #[inline]
- pub fn allocator(&self) -> &A {
- &self.alloc
- }
-
- fn as_raw_mut_slice(&mut self) -> *mut [T] {
- ptr::slice_from_raw_parts_mut(self.ptr as *mut T, self.len())
- }
-
- /// Drops remaining elements and relinquishes the backing allocation.
- /// This method guarantees it won't panic before relinquishing
- /// the backing allocation.
- ///
- /// This is roughly equivalent to the following, but more efficient
- ///
- /// ```
- /// # let mut into_iter = Vec::<u8>::with_capacity(10).into_iter();
- /// let mut into_iter = std::mem::replace(&mut into_iter, Vec::new().into_iter());
- /// (&mut into_iter).for_each(drop);
- /// std::mem::forget(into_iter);
- /// ```
- ///
- /// This method is used by in-place iteration, refer to the vec::in_place_collect
- /// documentation for an overview.
- #[cfg(not(no_global_oom_handling))]
- pub(super) fn forget_allocation_drop_remaining(&mut self) {
- let remaining = self.as_raw_mut_slice();
-
- // overwrite the individual fields instead of creating a new
- // struct and then overwriting &mut self.
- // this creates less assembly
- self.cap = 0;
- self.buf = unsafe { NonNull::new_unchecked(RawVec::NEW.ptr()) };
- self.ptr = self.buf.as_ptr();
- self.end = self.buf.as_ptr();
-
- // Dropping the remaining elements can panic, so this needs to be
- // done only after updating the other fields.
- unsafe {
- ptr::drop_in_place(remaining);
- }
- }
-
- /// Forgets to Drop the remaining elements while still allowing the backing allocation to be freed.
- pub(crate) fn forget_remaining_elements(&mut self) {
- // For th ZST case, it is crucial that we mutate `end` here, not `ptr`.
- // `ptr` must stay aligned, while `end` may be unaligned.
- self.end = self.ptr;
- }
-
- #[cfg(not(no_global_oom_handling))]
- #[inline]
- pub(crate) fn into_vecdeque(self) -> VecDeque<T, A> {
- // Keep our `Drop` impl from dropping the elements and the allocator
- let mut this = ManuallyDrop::new(self);
-
- // SAFETY: This allocation originally came from a `Vec`, so it passes
- // all those checks. We have `this.buf` ≤ `this.ptr` ≤ `this.end`,
- // so the `sub_ptr`s below cannot wrap, and will produce a well-formed
- // range. `end` ≤ `buf + cap`, so the range will be in-bounds.
- // Taking `alloc` is ok because nothing else is going to look at it,
- // since our `Drop` impl isn't going to run so there's no more code.
- unsafe {
- let buf = this.buf.as_ptr();
- let initialized = if T::IS_ZST {
- // All the pointers are the same for ZSTs, so it's fine to
- // say that they're all at the beginning of the "allocation".
- 0..this.len()
- } else {
- this.ptr.sub_ptr(buf)..this.end.sub_ptr(buf)
- };
- let cap = this.cap;
- let alloc = ManuallyDrop::take(&mut this.alloc);
- VecDeque::from_contiguous_raw_parts_in(buf, initialized, cap, alloc)
- }
- }
-}
-
-#[stable(feature = "vec_intoiter_as_ref", since = "1.46.0")]
-impl<T, A: Allocator> AsRef<[T]> for IntoIter<T, A> {
- fn as_ref(&self) -> &[T] {
- self.as_slice()
- }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-unsafe impl<T: Send, A: Allocator + Send> Send for IntoIter<T, A> {}
-#[stable(feature = "rust1", since = "1.0.0")]
-unsafe impl<T: Sync, A: Allocator + Sync> Sync for IntoIter<T, A> {}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<T, A: Allocator> Iterator for IntoIter<T, A> {
- type Item = T;
-
- #[inline]
- fn next(&mut self) -> Option<T> {
- if self.ptr == self.end {
- None
- } else if T::IS_ZST {
- // `ptr` has to stay where it is to remain aligned, so we reduce the length by 1 by
- // reducing the `end`.
- self.end = self.end.wrapping_byte_sub(1);
-
- // Make up a value of this ZST.
- Some(unsafe { mem::zeroed() })
- } else {
- let old = self.ptr;
- self.ptr = unsafe { self.ptr.add(1) };
-
- Some(unsafe { ptr::read(old) })
- }
- }
-
- #[inline]
- fn size_hint(&self) -> (usize, Option<usize>) {
- let exact = if T::IS_ZST {
- self.end.addr().wrapping_sub(self.ptr.addr())
- } else {
- unsafe { self.end.sub_ptr(self.ptr) }
- };
- (exact, Some(exact))
- }
-
- #[inline]
- fn advance_by(&mut self, n: usize) -> Result<(), NonZeroUsize> {
- let step_size = self.len().min(n);
- let to_drop = ptr::slice_from_raw_parts_mut(self.ptr as *mut T, step_size);
- if T::IS_ZST {
- // See `next` for why we sub `end` here.
- self.end = self.end.wrapping_byte_sub(step_size);
- } else {
- // SAFETY: the min() above ensures that step_size is in bounds
- self.ptr = unsafe { self.ptr.add(step_size) };
- }
- // SAFETY: the min() above ensures that step_size is in bounds
- unsafe {
- ptr::drop_in_place(to_drop);
- }
- NonZeroUsize::new(n - step_size).map_or(Ok(()), Err)
- }
-
- #[inline]
- fn count(self) -> usize {
- self.len()
- }
-
- #[inline]
- fn next_chunk<const N: usize>(&mut self) -> Result<[T; N], core::array::IntoIter<T, N>> {
- let mut raw_ary = MaybeUninit::uninit_array();
-
- let len = self.len();
-
- if T::IS_ZST {
- if len < N {
- self.forget_remaining_elements();
- // Safety: ZSTs can be conjured ex nihilo, only the amount has to be correct
- return Err(unsafe { array::IntoIter::new_unchecked(raw_ary, 0..len) });
- }
-
- self.end = self.end.wrapping_byte_sub(N);
- // Safety: ditto
- return Ok(unsafe { raw_ary.transpose().assume_init() });
- }
-
- if len < N {
- // Safety: `len` indicates that this many elements are available and we just checked that
- // it fits into the array.
- unsafe {
- ptr::copy_nonoverlapping(self.ptr, raw_ary.as_mut_ptr() as *mut T, len);
- self.forget_remaining_elements();
- return Err(array::IntoIter::new_unchecked(raw_ary, 0..len));
- }
- }
-
- // Safety: `len` is larger than the array size. Copy a fixed amount here to fully initialize
- // the array.
- return unsafe {
- ptr::copy_nonoverlapping(self.ptr, raw_ary.as_mut_ptr() as *mut T, N);
- self.ptr = self.ptr.add(N);
- Ok(raw_ary.transpose().assume_init())
- };
- }
-
- unsafe fn __iterator_get_unchecked(&mut self, i: usize) -> Self::Item
- where
- Self: TrustedRandomAccessNoCoerce,
- {
- // SAFETY: the caller must guarantee that `i` is in bounds of the
- // `Vec<T>`, so `i` cannot overflow an `isize`, and the `self.ptr.add(i)`
- // is guaranteed to pointer to an element of the `Vec<T>` and
- // thus guaranteed to be valid to dereference.
- //
- // Also note the implementation of `Self: TrustedRandomAccess` requires
- // that `T: Copy` so reading elements from the buffer doesn't invalidate
- // them for `Drop`.
- unsafe { if T::IS_ZST { mem::zeroed() } else { ptr::read(self.ptr.add(i)) } }
- }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<T, A: Allocator> DoubleEndedIterator for IntoIter<T, A> {
- #[inline]
- fn next_back(&mut self) -> Option<T> {
- if self.end == self.ptr {
- None
- } else if T::IS_ZST {
- // See above for why 'ptr.offset' isn't used
- self.end = self.end.wrapping_byte_sub(1);
-
- // Make up a value of this ZST.
- Some(unsafe { mem::zeroed() })
- } else {
- self.end = unsafe { self.end.sub(1) };
-
- Some(unsafe { ptr::read(self.end) })
- }
- }
-
- #[inline]
- fn advance_back_by(&mut self, n: usize) -> Result<(), NonZeroUsize> {
- let step_size = self.len().min(n);
- if T::IS_ZST {
- // SAFETY: same as for advance_by()
- self.end = self.end.wrapping_byte_sub(step_size);
- } else {
- // SAFETY: same as for advance_by()
- self.end = unsafe { self.end.sub(step_size) };
- }
- let to_drop = ptr::slice_from_raw_parts_mut(self.end as *mut T, step_size);
- // SAFETY: same as for advance_by()
- unsafe {
- ptr::drop_in_place(to_drop);
- }
- NonZeroUsize::new(n - step_size).map_or(Ok(()), Err)
- }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<T, A: Allocator> ExactSizeIterator for IntoIter<T, A> {
- fn is_empty(&self) -> bool {
- self.ptr == self.end
- }
-}
-
-#[stable(feature = "fused", since = "1.26.0")]
-impl<T, A: Allocator> FusedIterator for IntoIter<T, A> {}
-
-#[doc(hidden)]
-#[unstable(issue = "none", feature = "trusted_fused")]
-unsafe impl<T, A: Allocator> TrustedFused for IntoIter<T, A> {}
-
-#[unstable(feature = "trusted_len", issue = "37572")]
-unsafe impl<T, A: Allocator> TrustedLen for IntoIter<T, A> {}
-
-#[stable(feature = "default_iters", since = "1.70.0")]
-impl<T, A> Default for IntoIter<T, A>
-where
- A: Allocator + Default,
-{
- /// Creates an empty `vec::IntoIter`.
- ///
- /// ```
- /// # use std::vec;
- /// let iter: vec::IntoIter<u8> = Default::default();
- /// assert_eq!(iter.len(), 0);
- /// assert_eq!(iter.as_slice(), &[]);
- /// ```
- fn default() -> Self {
- super::Vec::new_in(Default::default()).into_iter()
- }
-}
-
-#[doc(hidden)]
-#[unstable(issue = "none", feature = "std_internals")]
-#[rustc_unsafe_specialization_marker]
-pub trait NonDrop {}
-
-// T: Copy as approximation for !Drop since get_unchecked does not advance self.ptr
-// and thus we can't implement drop-handling
-#[unstable(issue = "none", feature = "std_internals")]
-impl<T: Copy> NonDrop for T {}
-
-#[doc(hidden)]
-#[unstable(issue = "none", feature = "std_internals")]
-// TrustedRandomAccess (without NoCoerce) must not be implemented because
-// subtypes/supertypes of `T` might not be `NonDrop`
-unsafe impl<T, A: Allocator> TrustedRandomAccessNoCoerce for IntoIter<T, A>
-where
- T: NonDrop,
-{
- const MAY_HAVE_SIDE_EFFECT: bool = false;
-}
-
-#[cfg(not(no_global_oom_handling))]
-#[stable(feature = "vec_into_iter_clone", since = "1.8.0")]
-impl<T: Clone, A: Allocator + Clone> Clone for IntoIter<T, A> {
- #[cfg(not(test))]
- fn clone(&self) -> Self {
- self.as_slice().to_vec_in(self.alloc.deref().clone()).into_iter()
- }
- #[cfg(test)]
- fn clone(&self) -> Self {
- crate::slice::to_vec(self.as_slice(), self.alloc.deref().clone()).into_iter()
- }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-unsafe impl<#[may_dangle] T, A: Allocator> Drop for IntoIter<T, A> {
- fn drop(&mut self) {
- struct DropGuard<'a, T, A: Allocator>(&'a mut IntoIter<T, A>);
-
- impl<T, A: Allocator> Drop for DropGuard<'_, T, A> {
- fn drop(&mut self) {
- unsafe {
- // `IntoIter::alloc` is not used anymore after this and will be dropped by RawVec
- let alloc = ManuallyDrop::take(&mut self.0.alloc);
- // RawVec handles deallocation
- let _ = RawVec::from_raw_parts_in(self.0.buf.as_ptr(), self.0.cap, alloc);
- }
- }
- }
-
- let guard = DropGuard(self);
- // destroy the remaining elements
- unsafe {
- ptr::drop_in_place(guard.0.as_raw_mut_slice());
- }
- // now `guard` will be dropped and do the rest
- }
-}
-
-// In addition to the SAFETY invariants of the following three unsafe traits
-// also refer to the vec::in_place_collect module documentation to get an overview
-#[unstable(issue = "none", feature = "inplace_iteration")]
-#[doc(hidden)]
-unsafe impl<T, A: Allocator> InPlaceIterable for IntoIter<T, A> {
- const EXPAND_BY: Option<NonZeroUsize> = NonZeroUsize::new(1);
- const MERGE_BY: Option<NonZeroUsize> = NonZeroUsize::new(1);
-}
-
-#[unstable(issue = "none", feature = "inplace_iteration")]
-#[doc(hidden)]
-unsafe impl<T, A: Allocator> SourceIter for IntoIter<T, A> {
- type Source = Self;
-
- #[inline]
- unsafe fn as_inner(&mut self) -> &mut Self::Source {
- self
- }
-}
-
-#[cfg(not(no_global_oom_handling))]
-unsafe impl<T> AsVecIntoIter for IntoIter<T> {
- type Item = T;
-
- fn as_into_iter(&mut self) -> &mut IntoIter<Self::Item> {
- self
- }
-}
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