1 // Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 //! A doubly-linked list with owned nodes.
13 //! The `LinkedList` allows pushing and popping elements at either end and is thus
14 //! efficiently usable as a double-ended queue.
16 // LinkedList is constructed like a singly-linked list over the field `next`.
17 // including the last link being None; each Node owns its `next` field.
19 // Backlinks over LinkedList::prev are raw pointers that form a full chain in
20 // the reverse direction.
22 #![stable(feature = "rust1", since = "1.0.0")]
24 use alloc::boxed::{Box, IntermediateBox};
25 use core::cmp::Ordering;
27 use core::hash::{Hasher, Hash};
28 use core::iter::FromIterator;
30 use core::ops::{BoxPlace, InPlace, Place, Placer};
31 use core::ptr::{self, Shared};
33 /// A doubly-linked list.
34 #[stable(feature = "rust1", since = "1.0.0")]
35 pub struct LinkedList<T> {
38 list_tail: Rawlink<Node<T>>,
41 type Link<T> = Option<Box<Node<T>>>;
47 impl<T> Copy for Rawlink<T> {}
48 unsafe impl<T: Send> Send for Rawlink<T> {}
49 unsafe impl<T: Sync> Sync for Rawlink<T> {}
53 prev: Rawlink<Node<T>>,
57 /// An iterator over references to the items of a `LinkedList`.
58 #[stable(feature = "rust1", since = "1.0.0")]
59 pub struct Iter<'a, T: 'a> {
61 tail: Rawlink<Node<T>>,
65 // FIXME #19839: deriving is too aggressive on the bounds (T doesn't need to be Clone).
66 #[stable(feature = "rust1", since = "1.0.0")]
67 impl<'a, T> Clone for Iter<'a, T> {
68 fn clone(&self) -> Iter<'a, T> {
70 head: self.head.clone(),
77 /// An iterator over mutable references to the items of a `LinkedList`.
78 #[stable(feature = "rust1", since = "1.0.0")]
79 pub struct IterMut<'a, T: 'a> {
80 list: &'a mut LinkedList<T>,
81 head: Rawlink<Node<T>>,
82 tail: Rawlink<Node<T>>,
86 /// An iterator over the items of a `LinkedList`.
88 #[stable(feature = "rust1", since = "1.0.0")]
89 pub struct IntoIter<T> {
93 /// Rawlink is a type like Option<T> but for holding a raw pointer
95 /// Like Option::None for Rawlink
96 fn none() -> Rawlink<T> {
100 /// Like Option::Some for Rawlink
101 fn some(n: &mut T) -> Rawlink<T> {
102 unsafe { Rawlink { p: Some(Shared::new(n)) } }
105 /// Convert the `Rawlink` into an Option value
107 /// **unsafe** because:
109 /// - Dereference of raw pointer.
110 /// - Returns reference of arbitrary lifetime.
111 unsafe fn resolve<'a>(&self) -> Option<&'a T> {
115 /// Convert the `Rawlink` into an Option value
117 /// **unsafe** because:
119 /// - Dereference of raw pointer.
120 /// - Returns reference of arbitrary lifetime.
121 unsafe fn resolve_mut<'a>(&mut self) -> Option<&'a mut T> {
122 self.p.map(|p| &mut **p)
125 /// Return the `Rawlink` and replace with `Rawlink::none()`
126 fn take(&mut self) -> Rawlink<T> {
127 mem::replace(self, Rawlink::none())
131 impl<'a, T> From<&'a mut Link<T>> for Rawlink<Node<T>> {
132 fn from(node: &'a mut Link<T>) -> Self {
133 match node.as_mut() {
134 None => Rawlink::none(),
135 Some(ptr) => Rawlink::some(ptr),
140 impl<T> Clone for Rawlink<T> {
142 fn clone(&self) -> Rawlink<T> {
143 Rawlink { p: self.p }
148 fn new(v: T) -> Node<T> {
152 prev: Rawlink::none(),
156 /// Update the `prev` link on `next`, then set self's next pointer.
158 /// `self.next` should be `None` when you call this
159 /// (otherwise a Node is probably being dropped by mistake).
160 fn set_next(&mut self, mut next: Box<Node<T>>) {
161 debug_assert!(self.next.is_none());
162 next.prev = Rawlink::some(self);
163 self.next = Some(next);
167 /// Clear the .prev field on `next`, then return `Some(next)`
168 fn link_no_prev<T>(mut next: Box<Node<T>>) -> Link<T> {
169 next.prev = Rawlink::none();
174 impl<T> LinkedList<T> {
175 /// Add a Node first in the list
177 fn push_front_node(&mut self, mut new_head: Box<Node<T>>) {
178 match self.list_head {
180 self.list_head = link_no_prev(new_head);
181 self.list_tail = Rawlink::from(&mut self.list_head);
183 Some(ref mut head) => {
184 new_head.prev = Rawlink::none();
185 head.prev = Rawlink::some(&mut *new_head);
186 mem::swap(head, &mut new_head);
187 head.next = Some(new_head);
193 /// Remove the first Node and return it, or None if the list is empty
195 fn pop_front_node(&mut self) -> Option<Box<Node<T>>> {
196 self.list_head.take().map(|mut front_node| {
198 match front_node.next.take() {
199 Some(node) => self.list_head = link_no_prev(node),
200 None => self.list_tail = Rawlink::none(),
206 /// Add a Node last in the list
208 fn push_back_node(&mut self, new_tail: Box<Node<T>>) {
209 match unsafe { self.list_tail.resolve_mut() } {
210 None => return self.push_front_node(new_tail),
212 tail.set_next(new_tail);
213 self.list_tail = Rawlink::from(&mut tail.next);
219 /// Remove the last Node and return it, or None if the list is empty
221 fn pop_back_node(&mut self) -> Option<Box<Node<T>>> {
223 self.list_tail.resolve_mut().and_then(|tail| {
225 self.list_tail = tail.prev;
226 match tail.prev.resolve_mut() {
227 None => self.list_head.take(),
228 Some(tail_prev) => tail_prev.next.take(),
235 #[stable(feature = "rust1", since = "1.0.0")]
236 impl<T> Default for LinkedList<T> {
238 fn default() -> LinkedList<T> {
243 impl<T> LinkedList<T> {
244 /// Creates an empty `LinkedList`.
246 #[stable(feature = "rust1", since = "1.0.0")]
247 pub fn new() -> LinkedList<T> {
250 list_tail: Rawlink::none(),
255 /// Moves all elements from `other` to the end of the list.
257 /// This reuses all the nodes from `other` and moves them into `self`. After
258 /// this operation, `other` becomes empty.
260 /// This operation should compute in O(1) time and O(1) memory.
265 /// use std::collections::LinkedList;
267 /// let mut a = LinkedList::new();
268 /// let mut b = LinkedList::new();
274 /// a.append(&mut b);
277 /// println!("{}", e); // prints 1, then 2, then 3, then 4
279 /// println!("{}", b.len()); // prints 0
281 #[stable(feature = "rust1", since = "1.0.0")]
282 pub fn append(&mut self, other: &mut LinkedList<T>) {
283 match unsafe { self.list_tail.resolve_mut() } {
285 self.length = other.length;
286 self.list_head = other.list_head.take();
287 self.list_tail = other.list_tail.take();
290 // Carefully empty `other`.
291 let o_tail = other.list_tail.take();
292 let o_length = other.length;
293 match other.list_head.take() {
297 self.list_tail = o_tail;
298 self.length += o_length;
306 /// Provides a forward iterator.
308 #[stable(feature = "rust1", since = "1.0.0")]
309 pub fn iter(&self) -> Iter<T> {
312 head: &self.list_head,
313 tail: self.list_tail,
317 /// Provides a forward iterator with mutable references.
319 #[stable(feature = "rust1", since = "1.0.0")]
320 pub fn iter_mut(&mut self) -> IterMut<T> {
323 head: Rawlink::from(&mut self.list_head),
324 tail: self.list_tail,
329 /// Returns `true` if the `LinkedList` is empty.
331 /// This operation should compute in O(1) time.
336 /// use std::collections::LinkedList;
338 /// let mut dl = LinkedList::new();
339 /// assert!(dl.is_empty());
341 /// dl.push_front("foo");
342 /// assert!(!dl.is_empty());
345 #[stable(feature = "rust1", since = "1.0.0")]
346 pub fn is_empty(&self) -> bool {
347 self.list_head.is_none()
350 /// Returns the length of the `LinkedList`.
352 /// This operation should compute in O(1) time.
357 /// use std::collections::LinkedList;
359 /// let mut dl = LinkedList::new();
361 /// dl.push_front(2);
362 /// assert_eq!(dl.len(), 1);
364 /// dl.push_front(1);
365 /// assert_eq!(dl.len(), 2);
368 /// assert_eq!(dl.len(), 3);
372 #[stable(feature = "rust1", since = "1.0.0")]
373 pub fn len(&self) -> usize {
377 /// Removes all elements from the `LinkedList`.
379 /// This operation should compute in O(n) time.
384 /// use std::collections::LinkedList;
386 /// let mut dl = LinkedList::new();
388 /// dl.push_front(2);
389 /// dl.push_front(1);
390 /// assert_eq!(dl.len(), 2);
391 /// assert_eq!(dl.front(), Some(&1));
394 /// assert_eq!(dl.len(), 0);
395 /// assert_eq!(dl.front(), None);
399 #[stable(feature = "rust1", since = "1.0.0")]
400 pub fn clear(&mut self) {
401 *self = LinkedList::new()
404 /// Provides a reference to the front element, or `None` if the list is
410 /// use std::collections::LinkedList;
412 /// let mut dl = LinkedList::new();
413 /// assert_eq!(dl.front(), None);
415 /// dl.push_front(1);
416 /// assert_eq!(dl.front(), Some(&1));
420 #[stable(feature = "rust1", since = "1.0.0")]
421 pub fn front(&self) -> Option<&T> {
422 self.list_head.as_ref().map(|head| &head.value)
425 /// Provides a mutable reference to the front element, or `None` if the list
431 /// use std::collections::LinkedList;
433 /// let mut dl = LinkedList::new();
434 /// assert_eq!(dl.front(), None);
436 /// dl.push_front(1);
437 /// assert_eq!(dl.front(), Some(&1));
439 /// match dl.front_mut() {
441 /// Some(x) => *x = 5,
443 /// assert_eq!(dl.front(), Some(&5));
447 #[stable(feature = "rust1", since = "1.0.0")]
448 pub fn front_mut(&mut self) -> Option<&mut T> {
449 self.list_head.as_mut().map(|head| &mut head.value)
452 /// Provides a reference to the back element, or `None` if the list is
458 /// use std::collections::LinkedList;
460 /// let mut dl = LinkedList::new();
461 /// assert_eq!(dl.back(), None);
464 /// assert_eq!(dl.back(), Some(&1));
468 #[stable(feature = "rust1", since = "1.0.0")]
469 pub fn back(&self) -> Option<&T> {
470 unsafe { self.list_tail.resolve().map(|tail| &tail.value) }
473 /// Provides a mutable reference to the back element, or `None` if the list
479 /// use std::collections::LinkedList;
481 /// let mut dl = LinkedList::new();
482 /// assert_eq!(dl.back(), None);
485 /// assert_eq!(dl.back(), Some(&1));
487 /// match dl.back_mut() {
489 /// Some(x) => *x = 5,
491 /// assert_eq!(dl.back(), Some(&5));
495 #[stable(feature = "rust1", since = "1.0.0")]
496 pub fn back_mut(&mut self) -> Option<&mut T> {
497 unsafe { self.list_tail.resolve_mut().map(|tail| &mut tail.value) }
500 /// Adds an element first in the list.
502 /// This operation should compute in O(1) time.
507 /// use std::collections::LinkedList;
509 /// let mut dl = LinkedList::new();
511 /// dl.push_front(2);
512 /// assert_eq!(dl.front().unwrap(), &2);
514 /// dl.push_front(1);
515 /// assert_eq!(dl.front().unwrap(), &1);
518 #[stable(feature = "rust1", since = "1.0.0")]
519 pub fn push_front(&mut self, elt: T) {
520 self.push_front_node(box Node::new(elt))
523 /// Removes the first element and returns it, or `None` if the list is
526 /// This operation should compute in O(1) time.
531 /// use std::collections::LinkedList;
533 /// let mut d = LinkedList::new();
534 /// assert_eq!(d.pop_front(), None);
538 /// assert_eq!(d.pop_front(), Some(3));
539 /// assert_eq!(d.pop_front(), Some(1));
540 /// assert_eq!(d.pop_front(), None);
544 #[stable(feature = "rust1", since = "1.0.0")]
545 pub fn pop_front(&mut self) -> Option<T> {
546 self.pop_front_node().map(|box Node { value, .. }| value)
549 /// Appends an element to the back of a list
554 /// use std::collections::LinkedList;
556 /// let mut d = LinkedList::new();
559 /// assert_eq!(3, *d.back().unwrap());
561 #[stable(feature = "rust1", since = "1.0.0")]
562 pub fn push_back(&mut self, elt: T) {
563 self.push_back_node(box Node::new(elt))
566 /// Removes the last element from a list and returns it, or `None` if
572 /// use std::collections::LinkedList;
574 /// let mut d = LinkedList::new();
575 /// assert_eq!(d.pop_back(), None);
578 /// assert_eq!(d.pop_back(), Some(3));
580 #[stable(feature = "rust1", since = "1.0.0")]
581 pub fn pop_back(&mut self) -> Option<T> {
582 self.pop_back_node().map(|box Node { value, .. }| value)
585 /// Splits the list into two at the given index. Returns everything after the given index,
586 /// including the index.
590 /// Panics if `at > len`.
592 /// This operation should compute in O(n) time.
597 /// use std::collections::LinkedList;
599 /// let mut d = LinkedList::new();
605 /// let mut splitted = d.split_off(2);
607 /// assert_eq!(splitted.pop_front(), Some(1));
608 /// assert_eq!(splitted.pop_front(), None);
610 #[stable(feature = "rust1", since = "1.0.0")]
611 pub fn split_off(&mut self, at: usize) -> LinkedList<T> {
612 let len = self.len();
613 assert!(at <= len, "Cannot split off at a nonexistent index");
615 return mem::replace(self, LinkedList::new());
616 } else if at == len {
617 return LinkedList::new();
620 // Below, we iterate towards the `i-1`th node, either from the start or the end,
621 // depending on which would be faster.
622 let mut split_node = if at - 1 <= len - 1 - (at - 1) {
623 let mut iter = self.iter_mut();
624 // instead of skipping using .skip() (which creates a new struct),
625 // we skip manually so we can access the head field without
626 // depending on implementation details of Skip
632 // better off starting from the end
633 let mut iter = self.iter_mut();
634 for _ in 0..len - 1 - (at - 1) {
640 // The split node is the new tail node of the first part and owns
641 // the head of the second part.
642 let mut second_part_head;
645 second_part_head = split_node.resolve_mut().unwrap().next.take();
646 match second_part_head {
648 Some(ref mut head) => head.prev = Rawlink::none(),
652 let second_part = LinkedList {
653 list_head: second_part_head,
654 list_tail: self.list_tail,
658 // Fix the tail ptr of the first part
659 self.list_tail = split_node;
665 /// Returns a place for insertion at the front of the list.
667 /// Using this method with placement syntax is equivalent to [`push_front`]
668 /// (#method.push_front), but may be more efficient.
673 /// #![feature(collection_placement)]
674 /// #![feature(placement_in_syntax)]
676 /// use std::collections::LinkedList;
678 /// let mut list = LinkedList::new();
679 /// list.front_place() <- 2;
680 /// list.front_place() <- 4;
681 /// assert!(list.iter().eq(&[4, 2]));
683 #[unstable(feature = "collection_placement",
684 reason = "method name and placement protocol are subject to change",
686 pub fn front_place(&mut self) -> FrontPlace<T> {
687 FrontPlace { list: self, node: IntermediateBox::make_place() }
690 /// Returns a place for insertion at the back of the list.
692 /// Using this method with placement syntax is equivalent to [`push_back`](#method.push_back),
693 /// but may be more efficient.
698 /// #![feature(collection_placement)]
699 /// #![feature(placement_in_syntax)]
701 /// use std::collections::LinkedList;
703 /// let mut list = LinkedList::new();
704 /// list.back_place() <- 2;
705 /// list.back_place() <- 4;
706 /// assert!(list.iter().eq(&[2, 4]));
708 #[unstable(feature = "collection_placement",
709 reason = "method name and placement protocol are subject to change",
711 pub fn back_place(&mut self) -> BackPlace<T> {
712 BackPlace { list: self, node: IntermediateBox::make_place() }
716 #[stable(feature = "rust1", since = "1.0.0")]
717 impl<T> Drop for LinkedList<T> {
718 #[unsafe_destructor_blind_to_params]
720 // Dissolve the linked_list in a loop.
721 // Just dropping the list_head can lead to stack exhaustion
722 // when length is >> 1_000_000
723 while let Some(mut head_) = self.list_head.take() {
724 self.list_head = head_.next.take();
727 self.list_tail = Rawlink::none();
731 #[stable(feature = "rust1", since = "1.0.0")]
732 impl<'a, A> Iterator for Iter<'a, A> {
736 fn next(&mut self) -> Option<&'a A> {
740 self.head.as_ref().map(|head| {
742 self.head = &head.next;
748 fn size_hint(&self) -> (usize, Option<usize>) {
749 (self.nelem, Some(self.nelem))
753 #[stable(feature = "rust1", since = "1.0.0")]
754 impl<'a, A> DoubleEndedIterator for Iter<'a, A> {
756 fn next_back(&mut self) -> Option<&'a A> {
761 self.tail.resolve().map(|prev| {
763 self.tail = prev.prev;
770 #[stable(feature = "rust1", since = "1.0.0")]
771 impl<'a, A> ExactSizeIterator for Iter<'a, A> {}
773 #[stable(feature = "rust1", since = "1.0.0")]
774 impl<'a, A> Iterator for IterMut<'a, A> {
775 type Item = &'a mut A;
777 fn next(&mut self) -> Option<&'a mut A> {
782 self.head.resolve_mut().map(|next| {
784 self.head = Rawlink::from(&mut next.next);
791 fn size_hint(&self) -> (usize, Option<usize>) {
792 (self.nelem, Some(self.nelem))
796 #[stable(feature = "rust1", since = "1.0.0")]
797 impl<'a, A> DoubleEndedIterator for IterMut<'a, A> {
799 fn next_back(&mut self) -> Option<&'a mut A> {
804 self.tail.resolve_mut().map(|prev| {
806 self.tail = prev.prev;
813 #[stable(feature = "rust1", since = "1.0.0")]
814 impl<'a, A> ExactSizeIterator for IterMut<'a, A> {}
816 // private methods for IterMut
817 impl<'a, A> IterMut<'a, A> {
818 fn insert_next_node(&mut self, mut ins_node: Box<Node<A>>) {
819 // Insert before `self.head` so that it is between the
820 // previously yielded element and self.head.
822 // The inserted node will not appear in further iteration.
823 match unsafe { self.head.resolve_mut() } {
825 self.list.push_back_node(ins_node);
828 let prev_node = match unsafe { node.prev.resolve_mut() } {
829 None => return self.list.push_front_node(ins_node),
832 let node_own = prev_node.next.take().unwrap();
833 ins_node.set_next(node_own);
834 prev_node.set_next(ins_node);
835 self.list.length += 1;
841 impl<'a, A> IterMut<'a, A> {
842 /// Inserts `elt` just after the element most recently returned by `.next()`.
843 /// The inserted element does not appear in the iteration.
848 /// #![feature(linked_list_extras)]
850 /// use std::collections::LinkedList;
852 /// let mut list: LinkedList<_> = vec![1, 3, 4].into_iter().collect();
855 /// let mut it = list.iter_mut();
856 /// assert_eq!(it.next().unwrap(), &1);
857 /// // insert `2` after `1`
858 /// it.insert_next(2);
861 /// let vec: Vec<_> = list.into_iter().collect();
862 /// assert_eq!(vec, [1, 2, 3, 4]);
866 #[unstable(feature = "linked_list_extras",
867 reason = "this is probably better handled by a cursor type -- we'll see",
869 pub fn insert_next(&mut self, elt: A) {
870 self.insert_next_node(box Node::new(elt))
873 /// Provides a reference to the next element, without changing the iterator.
878 /// #![feature(linked_list_extras)]
880 /// use std::collections::LinkedList;
882 /// let mut list: LinkedList<_> = vec![1, 2, 3].into_iter().collect();
884 /// let mut it = list.iter_mut();
885 /// assert_eq!(it.next().unwrap(), &1);
886 /// assert_eq!(it.peek_next().unwrap(), &2);
887 /// // We just peeked at 2, so it was not consumed from the iterator.
888 /// assert_eq!(it.next().unwrap(), &2);
891 #[unstable(feature = "linked_list_extras",
892 reason = "this is probably better handled by a cursor type -- we'll see",
894 pub fn peek_next(&mut self) -> Option<&mut A> {
898 unsafe { self.head.resolve_mut().map(|head| &mut head.value) }
902 #[stable(feature = "rust1", since = "1.0.0")]
903 impl<A> Iterator for IntoIter<A> {
907 fn next(&mut self) -> Option<A> {
908 self.list.pop_front()
912 fn size_hint(&self) -> (usize, Option<usize>) {
913 (self.list.length, Some(self.list.length))
917 #[stable(feature = "rust1", since = "1.0.0")]
918 impl<A> DoubleEndedIterator for IntoIter<A> {
920 fn next_back(&mut self) -> Option<A> {
925 #[stable(feature = "rust1", since = "1.0.0")]
926 impl<A> ExactSizeIterator for IntoIter<A> {}
928 #[stable(feature = "rust1", since = "1.0.0")]
929 impl<A> FromIterator<A> for LinkedList<A> {
930 fn from_iter<T: IntoIterator<Item = A>>(iter: T) -> LinkedList<A> {
931 let mut ret = LinkedList::new();
937 #[stable(feature = "rust1", since = "1.0.0")]
938 impl<T> IntoIterator for LinkedList<T> {
940 type IntoIter = IntoIter<T>;
942 /// Consumes the list into an iterator yielding elements by value.
944 fn into_iter(self) -> IntoIter<T> {
945 IntoIter { list: self }
949 #[stable(feature = "rust1", since = "1.0.0")]
950 impl<'a, T> IntoIterator for &'a LinkedList<T> {
952 type IntoIter = Iter<'a, T>;
954 fn into_iter(self) -> Iter<'a, T> {
959 #[stable(feature = "rust1", since = "1.0.0")]
960 impl<'a, T> IntoIterator for &'a mut LinkedList<T> {
961 type Item = &'a mut T;
962 type IntoIter = IterMut<'a, T>;
964 fn into_iter(mut self) -> IterMut<'a, T> {
969 #[stable(feature = "rust1", since = "1.0.0")]
970 impl<A> Extend<A> for LinkedList<A> {
971 fn extend<T: IntoIterator<Item = A>>(&mut self, iter: T) {
978 #[stable(feature = "extend_ref", since = "1.2.0")]
979 impl<'a, T: 'a + Copy> Extend<&'a T> for LinkedList<T> {
980 fn extend<I: IntoIterator<Item = &'a T>>(&mut self, iter: I) {
981 self.extend(iter.into_iter().cloned());
985 #[stable(feature = "rust1", since = "1.0.0")]
986 impl<A: PartialEq> PartialEq for LinkedList<A> {
987 fn eq(&self, other: &LinkedList<A>) -> bool {
988 self.len() == other.len() && self.iter().eq(other.iter())
991 fn ne(&self, other: &LinkedList<A>) -> bool {
992 self.len() != other.len() || self.iter().ne(other.iter())
996 #[stable(feature = "rust1", since = "1.0.0")]
997 impl<A: Eq> Eq for LinkedList<A> {}
999 #[stable(feature = "rust1", since = "1.0.0")]
1000 impl<A: PartialOrd> PartialOrd for LinkedList<A> {
1001 fn partial_cmp(&self, other: &LinkedList<A>) -> Option<Ordering> {
1002 self.iter().partial_cmp(other.iter())
1006 #[stable(feature = "rust1", since = "1.0.0")]
1007 impl<A: Ord> Ord for LinkedList<A> {
1009 fn cmp(&self, other: &LinkedList<A>) -> Ordering {
1010 self.iter().cmp(other.iter())
1014 #[stable(feature = "rust1", since = "1.0.0")]
1015 impl<A: Clone> Clone for LinkedList<A> {
1016 fn clone(&self) -> LinkedList<A> {
1017 self.iter().cloned().collect()
1021 #[stable(feature = "rust1", since = "1.0.0")]
1022 impl<A: fmt::Debug> fmt::Debug for LinkedList<A> {
1023 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1024 f.debug_list().entries(self.iter()).finish()
1028 #[stable(feature = "rust1", since = "1.0.0")]
1029 impl<A: Hash> Hash for LinkedList<A> {
1030 fn hash<H: Hasher>(&self, state: &mut H) {
1031 self.len().hash(state);
1038 unsafe fn finalize<T>(node: IntermediateBox<Node<T>>) -> Box<Node<T>> {
1039 let mut node = node.finalize();
1040 ptr::write(&mut node.next, None);
1041 ptr::write(&mut node.prev, Rawlink::none());
1045 /// A place for insertion at the front of a `LinkedList`.
1047 /// See [`LinkedList::front_place`](struct.LinkedList.html#method.front_place) for details.
1048 #[must_use = "places do nothing unless written to with `<-` syntax"]
1049 #[unstable(feature = "collection_placement",
1050 reason = "struct name and placement protocol are subject to change",
1052 pub struct FrontPlace<'a, T: 'a> {
1053 list: &'a mut LinkedList<T>,
1054 node: IntermediateBox<Node<T>>,
1057 #[unstable(feature = "collection_placement",
1058 reason = "placement protocol is subject to change",
1060 impl<'a, T> Placer<T> for FrontPlace<'a, T> {
1063 fn make_place(self) -> Self {
1068 #[unstable(feature = "collection_placement",
1069 reason = "placement protocol is subject to change",
1071 impl<'a, T> Place<T> for FrontPlace<'a, T> {
1072 fn pointer(&mut self) -> *mut T {
1073 unsafe { &mut (*self.node.pointer()).value }
1077 #[unstable(feature = "collection_placement",
1078 reason = "placement protocol is subject to change",
1080 impl<'a, T> InPlace<T> for FrontPlace<'a, T> {
1083 unsafe fn finalize(self) {
1084 let FrontPlace { list, node } = self;
1085 list.push_front_node(finalize(node));
1089 /// A place for insertion at the back of a `LinkedList`.
1091 /// See [`LinkedList::back_place`](struct.LinkedList.html#method.back_place) for details.
1092 #[must_use = "places do nothing unless written to with `<-` syntax"]
1093 #[unstable(feature = "collection_placement",
1094 reason = "struct name and placement protocol are subject to change",
1096 pub struct BackPlace<'a, T: 'a> {
1097 list: &'a mut LinkedList<T>,
1098 node: IntermediateBox<Node<T>>,
1101 #[unstable(feature = "collection_placement",
1102 reason = "placement protocol is subject to change",
1104 impl<'a, T> Placer<T> for BackPlace<'a, T> {
1107 fn make_place(self) -> Self {
1112 #[unstable(feature = "collection_placement",
1113 reason = "placement protocol is subject to change",
1115 impl<'a, T> Place<T> for BackPlace<'a, T> {
1116 fn pointer(&mut self) -> *mut T {
1117 unsafe { &mut (*self.node.pointer()).value }
1121 #[unstable(feature = "collection_placement",
1122 reason = "placement protocol is subject to change",
1124 impl<'a, T> InPlace<T> for BackPlace<'a, T> {
1127 unsafe fn finalize(self) {
1128 let BackPlace { list, node } = self;
1129 list.push_back_node(finalize(node));
1133 // Ensure that `LinkedList` and its read-only iterators are covariant in their type parameters.
1135 fn assert_covariance() {
1136 fn a<'a>(x: LinkedList<&'static str>) -> LinkedList<&'a str> { x }
1137 fn b<'i, 'a>(x: Iter<'i, &'static str>) -> Iter<'i, &'a str> { x }
1138 fn c<'a>(x: IntoIter<&'static str>) -> IntoIter<&'a str> { x }
1143 use std::clone::Clone;
1144 use std::iter::{Iterator, IntoIterator, Extend};
1145 use std::option::Option::{self, Some, None};
1146 use std::__rand::{thread_rng, Rng};
1150 use super::{LinkedList, Node};
1153 fn list_from<T: Clone>(v: &[T]) -> LinkedList<T> {
1154 v.iter().cloned().collect()
1157 pub fn check_links<T>(list: &LinkedList<T>) {
1159 let mut last_ptr: Option<&Node<T>> = None;
1160 let mut node_ptr: &Node<T>;
1161 match list.list_head {
1163 assert_eq!(0, list.length);
1166 Some(ref node) => node_ptr = &**node,
1169 match unsafe { (last_ptr, node_ptr.prev.resolve()) } {
1171 (None, _) => panic!("prev link for list_head"),
1172 (Some(p), Some(pptr)) => {
1173 assert_eq!(p as *const Node<T>, pptr as *const Node<T>);
1175 _ => panic!("prev link is none, not good"),
1177 match node_ptr.next {
1179 last_ptr = Some(node_ptr);
1189 assert_eq!(len, list.length);
1196 let mut m = LinkedList::<i32>::new();
1197 let mut n = LinkedList::new();
1200 assert_eq!(m.len(), 0);
1201 assert_eq!(n.len(), 0);
1203 // Non-empty to empty
1205 let mut m = LinkedList::new();
1206 let mut n = LinkedList::new();
1210 assert_eq!(m.len(), 1);
1211 assert_eq!(m.pop_back(), Some(2));
1212 assert_eq!(n.len(), 0);
1215 // Empty to non-empty
1217 let mut m = LinkedList::new();
1218 let mut n = LinkedList::new();
1222 assert_eq!(m.len(), 1);
1223 assert_eq!(m.pop_back(), Some(2));
1227 // Non-empty to non-empty
1228 let v = vec![1, 2, 3, 4, 5];
1229 let u = vec![9, 8, 1, 2, 3, 4, 5];
1230 let mut m = list_from(&v);
1231 let mut n = list_from(&u);
1236 assert_eq!(sum.len(), m.len());
1238 assert_eq!(m.pop_front(), Some(elt))
1240 assert_eq!(n.len(), 0);
1241 // let's make sure it's working properly, since we
1242 // did some direct changes to private members
1244 assert_eq!(n.len(), 1);
1245 assert_eq!(n.pop_front(), Some(3));
1250 fn test_insert_prev() {
1251 let mut m = list_from(&[0, 2, 4, 6, 8]);
1254 let mut it = m.iter_mut();
1260 it.insert_next(*elt + 1);
1261 match it.peek_next() {
1262 Some(x) => assert_eq!(*x, *elt + 2),
1263 None => assert_eq!(8, *elt),
1272 assert_eq!(m.len(), 3 + len * 2);
1273 assert_eq!(m.into_iter().collect::<Vec<_>>(),
1274 [-2, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1]);
1279 let n = list_from(&[1, 2, 3]);
1280 thread::spawn(move || {
1282 let a: &[_] = &[&1, &2, &3];
1283 assert_eq!(a, &n.iter().collect::<Vec<_>>()[..]);
1301 use std::iter::ExactSizeIterator;
1302 // There was a bug in split_off that failed to null out the RHS's head's prev ptr.
1303 // This caused the RHS's dtor to walk up into the LHS at drop and delete all of
1306 // https://github.com/rust-lang/rust/issues/26021
1307 let mut v1 = LinkedList::new();
1312 let _ = v1.split_off(3); // Dropping this now should not cause laundry consumption
1313 assert_eq!(v1.len(), 3);
1315 assert_eq!(v1.iter().len(), 3);
1316 assert_eq!(v1.iter().collect::<Vec<_>>().len(), 3);
1320 fn test_split_off() {
1321 let mut v1 = LinkedList::new();
1328 for ix in 0..1 + v1.len() {
1329 let mut a = v1.clone();
1330 let b = a.split_off(ix);
1340 fn fuzz_test(sz: i32) {
1341 let mut m: LinkedList<_> = LinkedList::new();
1345 let r: u8 = thread_rng().next_u32() as u8;
1371 for (a, &b) in m.into_iter().zip(&v) {
1375 assert_eq!(i, v.len());