| // Copyright 2012-2015 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 doubly-linked list with owned nodes. |
| //! |
| //! The `LinkedList` allows pushing and popping elements at either end and is thus |
| //! efficiently usable as a double-ended queue. |
| |
| // LinkedList is constructed like a singly-linked list over the field `next`. |
| // including the last link being None; each Node owns its `next` field. |
| // |
| // Backlinks over LinkedList::prev are raw pointers that form a full chain in |
| // the reverse direction. |
| |
| #![stable(feature = "rust1", since = "1.0.0")] |
| |
| use alloc::boxed::Box; |
| use core::cmp::Ordering; |
| use core::fmt; |
| use core::hash::{Hasher, Hash}; |
| use core::iter::FromIterator; |
| use core::mem; |
| use core::ptr::Shared; |
| |
| /// A doubly-linked list. |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub struct LinkedList<T> { |
| length: usize, |
| list_head: Link<T>, |
| list_tail: Rawlink<Node<T>>, |
| } |
| |
| type Link<T> = Option<Box<Node<T>>>; |
| |
| struct Rawlink<T> { |
| p: Option<Shared<T>>, |
| } |
| |
| impl<T> Copy for Rawlink<T> {} |
| unsafe impl<T: Send> Send for Rawlink<T> {} |
| unsafe impl<T: Sync> Sync for Rawlink<T> {} |
| |
| struct Node<T> { |
| next: Link<T>, |
| prev: Rawlink<Node<T>>, |
| value: T, |
| } |
| |
| /// An iterator over references to the items of a `LinkedList`. |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub struct Iter<'a, T: 'a> { |
| head: &'a Link<T>, |
| tail: Rawlink<Node<T>>, |
| nelem: usize, |
| } |
| |
| // FIXME #19839: deriving is too aggressive on the bounds (T doesn't need to be Clone). |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<'a, T> Clone for Iter<'a, T> { |
| fn clone(&self) -> Iter<'a, T> { |
| Iter { |
| head: self.head.clone(), |
| tail: self.tail, |
| nelem: self.nelem, |
| } |
| } |
| } |
| |
| /// An iterator over mutable references to the items of a `LinkedList`. |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub struct IterMut<'a, T: 'a> { |
| list: &'a mut LinkedList<T>, |
| head: Rawlink<Node<T>>, |
| tail: Rawlink<Node<T>>, |
| nelem: usize, |
| } |
| |
| /// An iterator over mutable references to the items of a `LinkedList`. |
| #[derive(Clone)] |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub struct IntoIter<T> { |
| list: LinkedList<T>, |
| } |
| |
| /// Rawlink is a type like Option<T> but for holding a raw pointer |
| impl<T> Rawlink<T> { |
| /// Like Option::None for Rawlink |
| fn none() -> Rawlink<T> { |
| Rawlink { p: None } |
| } |
| |
| /// Like Option::Some for Rawlink |
| fn some(n: &mut T) -> Rawlink<T> { |
| unsafe { Rawlink { p: Some(Shared::new(n)) } } |
| } |
| |
| /// Convert the `Rawlink` into an Option value |
| /// |
| /// **unsafe** because: |
| /// |
| /// - Dereference of raw pointer. |
| /// - Returns reference of arbitrary lifetime. |
| unsafe fn resolve<'a>(&self) -> Option<&'a T> { |
| self.p.map(|p| &**p) |
| } |
| |
| /// Convert the `Rawlink` into an Option value |
| /// |
| /// **unsafe** because: |
| /// |
| /// - Dereference of raw pointer. |
| /// - Returns reference of arbitrary lifetime. |
| unsafe fn resolve_mut<'a>(&mut self) -> Option<&'a mut T> { |
| self.p.map(|p| &mut **p) |
| } |
| |
| /// Return the `Rawlink` and replace with `Rawlink::none()` |
| fn take(&mut self) -> Rawlink<T> { |
| mem::replace(self, Rawlink::none()) |
| } |
| } |
| |
| impl<'a, T> From<&'a mut Link<T>> for Rawlink<Node<T>> { |
| fn from(node: &'a mut Link<T>) -> Self { |
| match node.as_mut() { |
| None => Rawlink::none(), |
| Some(ptr) => Rawlink::some(ptr), |
| } |
| } |
| } |
| |
| impl<T> Clone for Rawlink<T> { |
| #[inline] |
| fn clone(&self) -> Rawlink<T> { |
| Rawlink { p: self.p } |
| } |
| } |
| |
| impl<T> Node<T> { |
| fn new(v: T) -> Node<T> { |
| Node { |
| value: v, |
| next: None, |
| prev: Rawlink::none(), |
| } |
| } |
| |
| /// Update the `prev` link on `next`, then set self's next pointer. |
| /// |
| /// `self.next` should be `None` when you call this |
| /// (otherwise a Node is probably being dropped by mistake). |
| fn set_next(&mut self, mut next: Box<Node<T>>) { |
| debug_assert!(self.next.is_none()); |
| next.prev = Rawlink::some(self); |
| self.next = Some(next); |
| } |
| } |
| |
| /// Clear the .prev field on `next`, then return `Some(next)` |
| fn link_no_prev<T>(mut next: Box<Node<T>>) -> Link<T> { |
| next.prev = Rawlink::none(); |
| Some(next) |
| } |
| |
| // private methods |
| impl<T> LinkedList<T> { |
| /// Add a Node first in the list |
| #[inline] |
| fn push_front_node(&mut self, mut new_head: Box<Node<T>>) { |
| match self.list_head { |
| None => { |
| self.list_head = link_no_prev(new_head); |
| self.list_tail = Rawlink::from(&mut self.list_head); |
| } |
| Some(ref mut head) => { |
| new_head.prev = Rawlink::none(); |
| head.prev = Rawlink::some(&mut *new_head); |
| mem::swap(head, &mut new_head); |
| head.next = Some(new_head); |
| } |
| } |
| self.length += 1; |
| } |
| |
| /// Remove the first Node and return it, or None if the list is empty |
| #[inline] |
| fn pop_front_node(&mut self) -> Option<Box<Node<T>>> { |
| self.list_head.take().map(|mut front_node| { |
| self.length -= 1; |
| match front_node.next.take() { |
| Some(node) => self.list_head = link_no_prev(node), |
| None => self.list_tail = Rawlink::none(), |
| } |
| front_node |
| }) |
| } |
| |
| /// Add a Node last in the list |
| #[inline] |
| fn push_back_node(&mut self, new_tail: Box<Node<T>>) { |
| match unsafe { self.list_tail.resolve_mut() } { |
| None => return self.push_front_node(new_tail), |
| Some(tail) => { |
| tail.set_next(new_tail); |
| self.list_tail = Rawlink::from(&mut tail.next); |
| } |
| } |
| self.length += 1; |
| } |
| |
| /// Remove the last Node and return it, or None if the list is empty |
| #[inline] |
| fn pop_back_node(&mut self) -> Option<Box<Node<T>>> { |
| unsafe { |
| self.list_tail.resolve_mut().and_then(|tail| { |
| self.length -= 1; |
| self.list_tail = tail.prev; |
| match tail.prev.resolve_mut() { |
| None => self.list_head.take(), |
| Some(tail_prev) => tail_prev.next.take(), |
| } |
| }) |
| } |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T> Default for LinkedList<T> { |
| #[inline] |
| fn default() -> LinkedList<T> { |
| LinkedList::new() |
| } |
| } |
| |
| impl<T> LinkedList<T> { |
| /// Creates an empty `LinkedList`. |
| #[inline] |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn new() -> LinkedList<T> { |
| LinkedList { |
| list_head: None, |
| list_tail: Rawlink::none(), |
| length: 0, |
| } |
| } |
| |
| /// Moves all elements from `other` to the end of the list. |
| /// |
| /// This reuses all the nodes from `other` and moves them into `self`. After |
| /// this operation, `other` becomes empty. |
| /// |
| /// This operation should compute in O(1) time and O(1) memory. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::collections::LinkedList; |
| /// |
| /// let mut a = LinkedList::new(); |
| /// let mut b = LinkedList::new(); |
| /// a.push_back(1); |
| /// a.push_back(2); |
| /// b.push_back(3); |
| /// b.push_back(4); |
| /// |
| /// a.append(&mut b); |
| /// |
| /// for e in &a { |
| /// println!("{}", e); // prints 1, then 2, then 3, then 4 |
| /// } |
| /// println!("{}", b.len()); // prints 0 |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn append(&mut self, other: &mut LinkedList<T>) { |
| match unsafe { self.list_tail.resolve_mut() } { |
| None => { |
| self.length = other.length; |
| self.list_head = other.list_head.take(); |
| self.list_tail = other.list_tail.take(); |
| } |
| Some(tail) => { |
| // Carefully empty `other`. |
| let o_tail = other.list_tail.take(); |
| let o_length = other.length; |
| match other.list_head.take() { |
| None => return, |
| Some(node) => { |
| tail.set_next(node); |
| self.list_tail = o_tail; |
| self.length += o_length; |
| } |
| } |
| } |
| } |
| other.length = 0; |
| } |
| |
| /// Provides a forward iterator. |
| #[inline] |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn iter(&self) -> Iter<T> { |
| Iter { |
| nelem: self.len(), |
| head: &self.list_head, |
| tail: self.list_tail, |
| } |
| } |
| |
| /// Provides a forward iterator with mutable references. |
| #[inline] |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn iter_mut(&mut self) -> IterMut<T> { |
| IterMut { |
| nelem: self.len(), |
| head: Rawlink::from(&mut self.list_head), |
| tail: self.list_tail, |
| list: self, |
| } |
| } |
| |
| /// Returns `true` if the `LinkedList` is empty. |
| /// |
| /// This operation should compute in O(1) time. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::collections::LinkedList; |
| /// |
| /// let mut dl = LinkedList::new(); |
| /// assert!(dl.is_empty()); |
| /// |
| /// dl.push_front("foo"); |
| /// assert!(!dl.is_empty()); |
| /// ``` |
| #[inline] |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn is_empty(&self) -> bool { |
| self.list_head.is_none() |
| } |
| |
| /// Returns the length of the `LinkedList`. |
| /// |
| /// This operation should compute in O(1) time. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::collections::LinkedList; |
| /// |
| /// let mut dl = LinkedList::new(); |
| /// |
| /// dl.push_front(2); |
| /// assert_eq!(dl.len(), 1); |
| /// |
| /// dl.push_front(1); |
| /// assert_eq!(dl.len(), 2); |
| /// |
| /// dl.push_back(3); |
| /// assert_eq!(dl.len(), 3); |
| /// |
| /// ``` |
| #[inline] |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn len(&self) -> usize { |
| self.length |
| } |
| |
| /// Removes all elements from the `LinkedList`. |
| /// |
| /// This operation should compute in O(n) time. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::collections::LinkedList; |
| /// |
| /// let mut dl = LinkedList::new(); |
| /// |
| /// dl.push_front(2); |
| /// dl.push_front(1); |
| /// assert_eq!(dl.len(), 2); |
| /// assert_eq!(dl.front(), Some(&1)); |
| /// |
| /// dl.clear(); |
| /// assert_eq!(dl.len(), 0); |
| /// assert_eq!(dl.front(), None); |
| /// |
| /// ``` |
| #[inline] |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn clear(&mut self) { |
| *self = LinkedList::new() |
| } |
| |
| /// Provides a reference to the front element, or `None` if the list is |
| /// empty. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::collections::LinkedList; |
| /// |
| /// let mut dl = LinkedList::new(); |
| /// assert_eq!(dl.front(), None); |
| /// |
| /// dl.push_front(1); |
| /// assert_eq!(dl.front(), Some(&1)); |
| /// |
| /// ``` |
| #[inline] |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn front(&self) -> Option<&T> { |
| self.list_head.as_ref().map(|head| &head.value) |
| } |
| |
| /// Provides a mutable reference to the front element, or `None` if the list |
| /// is empty. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::collections::LinkedList; |
| /// |
| /// let mut dl = LinkedList::new(); |
| /// assert_eq!(dl.front(), None); |
| /// |
| /// dl.push_front(1); |
| /// assert_eq!(dl.front(), Some(&1)); |
| /// |
| /// match dl.front_mut() { |
| /// None => {}, |
| /// Some(x) => *x = 5, |
| /// } |
| /// assert_eq!(dl.front(), Some(&5)); |
| /// |
| /// ``` |
| #[inline] |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn front_mut(&mut self) -> Option<&mut T> { |
| self.list_head.as_mut().map(|head| &mut head.value) |
| } |
| |
| /// Provides a reference to the back element, or `None` if the list is |
| /// empty. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::collections::LinkedList; |
| /// |
| /// let mut dl = LinkedList::new(); |
| /// assert_eq!(dl.back(), None); |
| /// |
| /// dl.push_back(1); |
| /// assert_eq!(dl.back(), Some(&1)); |
| /// |
| /// ``` |
| #[inline] |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn back(&self) -> Option<&T> { |
| unsafe { self.list_tail.resolve().map(|tail| &tail.value) } |
| } |
| |
| /// Provides a mutable reference to the back element, or `None` if the list |
| /// is empty. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::collections::LinkedList; |
| /// |
| /// let mut dl = LinkedList::new(); |
| /// assert_eq!(dl.back(), None); |
| /// |
| /// dl.push_back(1); |
| /// assert_eq!(dl.back(), Some(&1)); |
| /// |
| /// match dl.back_mut() { |
| /// None => {}, |
| /// Some(x) => *x = 5, |
| /// } |
| /// assert_eq!(dl.back(), Some(&5)); |
| /// |
| /// ``` |
| #[inline] |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn back_mut(&mut self) -> Option<&mut T> { |
| unsafe { self.list_tail.resolve_mut().map(|tail| &mut tail.value) } |
| } |
| |
| /// Adds an element first in the list. |
| /// |
| /// This operation should compute in O(1) time. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::collections::LinkedList; |
| /// |
| /// let mut dl = LinkedList::new(); |
| /// |
| /// dl.push_front(2); |
| /// assert_eq!(dl.front().unwrap(), &2); |
| /// |
| /// dl.push_front(1); |
| /// assert_eq!(dl.front().unwrap(), &1); |
| /// |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn push_front(&mut self, elt: T) { |
| self.push_front_node(box Node::new(elt)) |
| } |
| |
| /// Removes the first element and returns it, or `None` if the list is |
| /// empty. |
| /// |
| /// This operation should compute in O(1) time. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::collections::LinkedList; |
| /// |
| /// let mut d = LinkedList::new(); |
| /// assert_eq!(d.pop_front(), None); |
| /// |
| /// d.push_front(1); |
| /// d.push_front(3); |
| /// assert_eq!(d.pop_front(), Some(3)); |
| /// assert_eq!(d.pop_front(), Some(1)); |
| /// assert_eq!(d.pop_front(), None); |
| /// |
| /// ``` |
| /// |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn pop_front(&mut self) -> Option<T> { |
| self.pop_front_node().map(|box Node { value, .. }| value) |
| } |
| |
| /// Appends an element to the back of a list |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::collections::LinkedList; |
| /// |
| /// let mut d = LinkedList::new(); |
| /// d.push_back(1); |
| /// d.push_back(3); |
| /// assert_eq!(3, *d.back().unwrap()); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn push_back(&mut self, elt: T) { |
| self.push_back_node(box Node::new(elt)) |
| } |
| |
| /// Removes the last element from a list and returns it, or `None` if |
| /// it is empty. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::collections::LinkedList; |
| /// |
| /// let mut d = LinkedList::new(); |
| /// assert_eq!(d.pop_back(), None); |
| /// d.push_back(1); |
| /// d.push_back(3); |
| /// assert_eq!(d.pop_back(), Some(3)); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn pop_back(&mut self) -> Option<T> { |
| self.pop_back_node().map(|box Node { value, .. }| value) |
| } |
| |
| /// Splits the list into two at the given index. Returns everything after the given index, |
| /// including the index. |
| /// |
| /// # Panics |
| /// |
| /// Panics if `at > len`. |
| /// |
| /// This operation should compute in O(n) time. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::collections::LinkedList; |
| /// |
| /// let mut d = LinkedList::new(); |
| /// |
| /// d.push_front(1); |
| /// d.push_front(2); |
| /// d.push_front(3); |
| /// |
| /// let mut splitted = d.split_off(2); |
| /// |
| /// assert_eq!(splitted.pop_front(), Some(1)); |
| /// assert_eq!(splitted.pop_front(), None); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn split_off(&mut self, at: usize) -> LinkedList<T> { |
| let len = self.len(); |
| assert!(at <= len, "Cannot split off at a nonexistent index"); |
| if at == 0 { |
| return mem::replace(self, LinkedList::new()); |
| } else if at == len { |
| return LinkedList::new(); |
| } |
| |
| // Below, we iterate towards the `i-1`th node, either from the start or the end, |
| // depending on which would be faster. |
| let mut split_node = if at - 1 <= len - 1 - (at - 1) { |
| let mut iter = self.iter_mut(); |
| // instead of skipping using .skip() (which creates a new struct), |
| // we skip manually so we can access the head field without |
| // depending on implementation details of Skip |
| for _ in 0..at - 1 { |
| iter.next(); |
| } |
| iter.head |
| } else { |
| // better off starting from the end |
| let mut iter = self.iter_mut(); |
| for _ in 0..len - 1 - (at - 1) { |
| iter.next_back(); |
| } |
| iter.tail |
| }; |
| |
| // The split node is the new tail node of the first part and owns |
| // the head of the second part. |
| let mut second_part_head; |
| |
| unsafe { |
| second_part_head = split_node.resolve_mut().unwrap().next.take(); |
| match second_part_head { |
| None => {} |
| Some(ref mut head) => head.prev = Rawlink::none(), |
| } |
| } |
| |
| let second_part = LinkedList { |
| list_head: second_part_head, |
| list_tail: self.list_tail, |
| length: len - at, |
| }; |
| |
| // Fix the tail ptr of the first part |
| self.list_tail = split_node; |
| self.length = at; |
| |
| second_part |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T> Drop for LinkedList<T> { |
| #[unsafe_destructor_blind_to_params] |
| fn drop(&mut self) { |
| // Dissolve the linked_list in a loop. |
| // Just dropping the list_head can lead to stack exhaustion |
| // when length is >> 1_000_000 |
| while let Some(mut head_) = self.list_head.take() { |
| self.list_head = head_.next.take(); |
| } |
| self.length = 0; |
| self.list_tail = Rawlink::none(); |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<'a, A> Iterator for Iter<'a, A> { |
| type Item = &'a A; |
| |
| #[inline] |
| fn next(&mut self) -> Option<&'a A> { |
| if self.nelem == 0 { |
| return None; |
| } |
| self.head.as_ref().map(|head| { |
| self.nelem -= 1; |
| self.head = &head.next; |
| &head.value |
| }) |
| } |
| |
| #[inline] |
| fn size_hint(&self) -> (usize, Option<usize>) { |
| (self.nelem, Some(self.nelem)) |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<'a, A> DoubleEndedIterator for Iter<'a, A> { |
| #[inline] |
| fn next_back(&mut self) -> Option<&'a A> { |
| if self.nelem == 0 { |
| return None; |
| } |
| unsafe { |
| self.tail.resolve().map(|prev| { |
| self.nelem -= 1; |
| self.tail = prev.prev; |
| &prev.value |
| }) |
| } |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<'a, A> ExactSizeIterator for Iter<'a, A> {} |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<'a, A> Iterator for IterMut<'a, A> { |
| type Item = &'a mut A; |
| #[inline] |
| fn next(&mut self) -> Option<&'a mut A> { |
| if self.nelem == 0 { |
| return None; |
| } |
| unsafe { |
| self.head.resolve_mut().map(|next| { |
| self.nelem -= 1; |
| self.head = Rawlink::from(&mut next.next); |
| &mut next.value |
| }) |
| } |
| } |
| |
| #[inline] |
| fn size_hint(&self) -> (usize, Option<usize>) { |
| (self.nelem, Some(self.nelem)) |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<'a, A> DoubleEndedIterator for IterMut<'a, A> { |
| #[inline] |
| fn next_back(&mut self) -> Option<&'a mut A> { |
| if self.nelem == 0 { |
| return None; |
| } |
| unsafe { |
| self.tail.resolve_mut().map(|prev| { |
| self.nelem -= 1; |
| self.tail = prev.prev; |
| &mut prev.value |
| }) |
| } |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<'a, A> ExactSizeIterator for IterMut<'a, A> {} |
| |
| // private methods for IterMut |
| impl<'a, A> IterMut<'a, A> { |
| fn insert_next_node(&mut self, mut ins_node: Box<Node<A>>) { |
| // Insert before `self.head` so that it is between the |
| // previously yielded element and self.head. |
| // |
| // The inserted node will not appear in further iteration. |
| match unsafe { self.head.resolve_mut() } { |
| None => { |
| self.list.push_back_node(ins_node); |
| } |
| Some(node) => { |
| let prev_node = match unsafe { node.prev.resolve_mut() } { |
| None => return self.list.push_front_node(ins_node), |
| Some(prev) => prev, |
| }; |
| let node_own = prev_node.next.take().unwrap(); |
| ins_node.set_next(node_own); |
| prev_node.set_next(ins_node); |
| self.list.length += 1; |
| } |
| } |
| } |
| } |
| |
| impl<'a, A> IterMut<'a, A> { |
| /// Inserts `elt` just after the element most recently returned by `.next()`. |
| /// The inserted element does not appear in the iteration. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// #![feature(linked_list_extras)] |
| /// |
| /// use std::collections::LinkedList; |
| /// |
| /// let mut list: LinkedList<_> = vec![1, 3, 4].into_iter().collect(); |
| /// |
| /// { |
| /// let mut it = list.iter_mut(); |
| /// assert_eq!(it.next().unwrap(), &1); |
| /// // insert `2` after `1` |
| /// it.insert_next(2); |
| /// } |
| /// { |
| /// let vec: Vec<_> = list.into_iter().collect(); |
| /// assert_eq!(vec, [1, 2, 3, 4]); |
| /// } |
| /// ``` |
| #[inline] |
| #[unstable(feature = "linked_list_extras", |
| reason = "this is probably better handled by a cursor type -- we'll see", |
| issue = "27794")] |
| pub fn insert_next(&mut self, elt: A) { |
| self.insert_next_node(box Node::new(elt)) |
| } |
| |
| /// Provides a reference to the next element, without changing the iterator. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// #![feature(linked_list_extras)] |
| /// |
| /// use std::collections::LinkedList; |
| /// |
| /// let mut list: LinkedList<_> = vec![1, 2, 3].into_iter().collect(); |
| /// |
| /// let mut it = list.iter_mut(); |
| /// assert_eq!(it.next().unwrap(), &1); |
| /// assert_eq!(it.peek_next().unwrap(), &2); |
| /// // We just peeked at 2, so it was not consumed from the iterator. |
| /// assert_eq!(it.next().unwrap(), &2); |
| /// ``` |
| #[inline] |
| #[unstable(feature = "linked_list_extras", |
| reason = "this is probably better handled by a cursor type -- we'll see", |
| issue = "27794")] |
| pub fn peek_next(&mut self) -> Option<&mut A> { |
| if self.nelem == 0 { |
| return None; |
| } |
| unsafe { self.head.resolve_mut().map(|head| &mut head.value) } |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<A> Iterator for IntoIter<A> { |
| type Item = A; |
| |
| #[inline] |
| fn next(&mut self) -> Option<A> { |
| self.list.pop_front() |
| } |
| |
| #[inline] |
| fn size_hint(&self) -> (usize, Option<usize>) { |
| (self.list.length, Some(self.list.length)) |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<A> DoubleEndedIterator for IntoIter<A> { |
| #[inline] |
| fn next_back(&mut self) -> Option<A> { |
| self.list.pop_back() |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<A> ExactSizeIterator for IntoIter<A> {} |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<A> FromIterator<A> for LinkedList<A> { |
| fn from_iter<T: IntoIterator<Item = A>>(iter: T) -> LinkedList<A> { |
| let mut ret = LinkedList::new(); |
| ret.extend(iter); |
| ret |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T> IntoIterator for LinkedList<T> { |
| type Item = T; |
| type IntoIter = IntoIter<T>; |
| |
| /// Consumes the list into an iterator yielding elements by value. |
| #[inline] |
| fn into_iter(self) -> IntoIter<T> { |
| IntoIter { list: self } |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<'a, T> IntoIterator for &'a LinkedList<T> { |
| type Item = &'a T; |
| type IntoIter = Iter<'a, T>; |
| |
| fn into_iter(self) -> Iter<'a, T> { |
| self.iter() |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<'a, T> IntoIterator for &'a mut LinkedList<T> { |
| type Item = &'a mut T; |
| type IntoIter = IterMut<'a, T>; |
| |
| fn into_iter(mut self) -> IterMut<'a, T> { |
| self.iter_mut() |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<A> Extend<A> for LinkedList<A> { |
| fn extend<T: IntoIterator<Item = A>>(&mut self, iter: T) { |
| for elt in iter { |
| self.push_back(elt); |
| } |
| } |
| } |
| |
| #[stable(feature = "extend_ref", since = "1.2.0")] |
| impl<'a, T: 'a + Copy> Extend<&'a T> for LinkedList<T> { |
| fn extend<I: IntoIterator<Item = &'a T>>(&mut self, iter: I) { |
| self.extend(iter.into_iter().cloned()); |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<A: PartialEq> PartialEq for LinkedList<A> { |
| fn eq(&self, other: &LinkedList<A>) -> bool { |
| self.len() == other.len() && self.iter().eq(other.iter()) |
| } |
| |
| fn ne(&self, other: &LinkedList<A>) -> bool { |
| self.len() != other.len() || self.iter().ne(other.iter()) |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<A: Eq> Eq for LinkedList<A> {} |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<A: PartialOrd> PartialOrd for LinkedList<A> { |
| fn partial_cmp(&self, other: &LinkedList<A>) -> Option<Ordering> { |
| self.iter().partial_cmp(other.iter()) |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<A: Ord> Ord for LinkedList<A> { |
| #[inline] |
| fn cmp(&self, other: &LinkedList<A>) -> Ordering { |
| self.iter().cmp(other.iter()) |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<A: Clone> Clone for LinkedList<A> { |
| fn clone(&self) -> LinkedList<A> { |
| self.iter().cloned().collect() |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<A: fmt::Debug> fmt::Debug for LinkedList<A> { |
| fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { |
| f.debug_list().entries(self.iter()).finish() |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<A: Hash> Hash for LinkedList<A> { |
| fn hash<H: Hasher>(&self, state: &mut H) { |
| self.len().hash(state); |
| for elt in self { |
| elt.hash(state); |
| } |
| } |
| } |
| |
| // Ensure that `LinkedList` and its read-only iterators are covariant in their type parameters. |
| #[allow(dead_code)] |
| fn assert_covariance() { |
| fn a<'a>(x: LinkedList<&'static str>) -> LinkedList<&'a str> { x } |
| fn b<'i, 'a>(x: Iter<'i, &'static str>) -> Iter<'i, &'a str> { x } |
| fn c<'a>(x: IntoIter<&'static str>) -> IntoIter<&'a str> { x } |
| } |
| |
| #[cfg(test)] |
| mod tests { |
| use std::clone::Clone; |
| use std::iter::{Iterator, IntoIterator, Extend}; |
| use std::option::Option::{self, Some, None}; |
| use std::__rand::{thread_rng, Rng}; |
| use std::thread; |
| use std::vec::Vec; |
| |
| use super::{LinkedList, Node}; |
| |
| #[cfg(test)] |
| fn list_from<T: Clone>(v: &[T]) -> LinkedList<T> { |
| v.iter().cloned().collect() |
| } |
| |
| pub fn check_links<T>(list: &LinkedList<T>) { |
| let mut len = 0; |
| let mut last_ptr: Option<&Node<T>> = None; |
| let mut node_ptr: &Node<T>; |
| match list.list_head { |
| None => { |
| assert_eq!(0, list.length); |
| return; |
| } |
| Some(ref node) => node_ptr = &**node, |
| } |
| loop { |
| match unsafe { (last_ptr, node_ptr.prev.resolve()) } { |
| (None, None) => {} |
| (None, _) => panic!("prev link for list_head"), |
| (Some(p), Some(pptr)) => { |
| assert_eq!(p as *const Node<T>, pptr as *const Node<T>); |
| } |
| _ => panic!("prev link is none, not good"), |
| } |
| match node_ptr.next { |
| Some(ref next) => { |
| last_ptr = Some(node_ptr); |
| node_ptr = &**next; |
| len += 1; |
| } |
| None => { |
| len += 1; |
| break; |
| } |
| } |
| } |
| assert_eq!(len, list.length); |
| } |
| |
| #[test] |
| fn test_append() { |
| // Empty to empty |
| { |
| let mut m = LinkedList::<i32>::new(); |
| let mut n = LinkedList::new(); |
| m.append(&mut n); |
| check_links(&m); |
| assert_eq!(m.len(), 0); |
| assert_eq!(n.len(), 0); |
| } |
| // Non-empty to empty |
| { |
| let mut m = LinkedList::new(); |
| let mut n = LinkedList::new(); |
| n.push_back(2); |
| m.append(&mut n); |
| check_links(&m); |
| assert_eq!(m.len(), 1); |
| assert_eq!(m.pop_back(), Some(2)); |
| assert_eq!(n.len(), 0); |
| check_links(&m); |
| } |
| // Empty to non-empty |
| { |
| let mut m = LinkedList::new(); |
| let mut n = LinkedList::new(); |
| m.push_back(2); |
| m.append(&mut n); |
| check_links(&m); |
| assert_eq!(m.len(), 1); |
| assert_eq!(m.pop_back(), Some(2)); |
| check_links(&m); |
| } |
| |
| // Non-empty to non-empty |
| let v = vec![1, 2, 3, 4, 5]; |
| let u = vec![9, 8, 1, 2, 3, 4, 5]; |
| let mut m = list_from(&v); |
| let mut n = list_from(&u); |
| m.append(&mut n); |
| check_links(&m); |
| let mut sum = v; |
| sum.push_all(&u); |
| assert_eq!(sum.len(), m.len()); |
| for elt in sum { |
| assert_eq!(m.pop_front(), Some(elt)) |
| } |
| assert_eq!(n.len(), 0); |
| // let's make sure it's working properly, since we |
| // did some direct changes to private members |
| n.push_back(3); |
| assert_eq!(n.len(), 1); |
| assert_eq!(n.pop_front(), Some(3)); |
| check_links(&n); |
| } |
| |
| #[test] |
| fn test_insert_prev() { |
| let mut m = list_from(&[0, 2, 4, 6, 8]); |
| let len = m.len(); |
| { |
| let mut it = m.iter_mut(); |
| it.insert_next(-2); |
| loop { |
| match it.next() { |
| None => break, |
| Some(elt) => { |
| it.insert_next(*elt + 1); |
| match it.peek_next() { |
| Some(x) => assert_eq!(*x, *elt + 2), |
| None => assert_eq!(8, *elt), |
| } |
| } |
| } |
| } |
| it.insert_next(0); |
| it.insert_next(1); |
| } |
| check_links(&m); |
| assert_eq!(m.len(), 3 + len * 2); |
| assert_eq!(m.into_iter().collect::<Vec<_>>(), |
| [-2, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1]); |
| } |
| |
| #[test] |
| fn test_send() { |
| let n = list_from(&[1, 2, 3]); |
| thread::spawn(move || { |
| check_links(&n); |
| let a: &[_] = &[&1, &2, &3]; |
| assert_eq!(a, &n.iter().collect::<Vec<_>>()[..]); |
| }) |
| .join() |
| .ok() |
| .unwrap(); |
| } |
| |
| #[test] |
| fn test_fuzz() { |
| for _ in 0..25 { |
| fuzz_test(3); |
| fuzz_test(16); |
| fuzz_test(189); |
| } |
| } |
| |
| #[test] |
| fn test_26021() { |
| use std::iter::ExactSizeIterator; |
| // There was a bug in split_off that failed to null out the RHS's head's prev ptr. |
| // This caused the RHS's dtor to walk up into the LHS at drop and delete all of |
| // its nodes. |
| // |
| // https://github.com/rust-lang/rust/issues/26021 |
| let mut v1 = LinkedList::new(); |
| v1.push_front(1u8); |
| v1.push_front(1u8); |
| v1.push_front(1u8); |
| v1.push_front(1u8); |
| let _ = v1.split_off(3); // Dropping this now should not cause laundry consumption |
| assert_eq!(v1.len(), 3); |
| |
| assert_eq!(v1.iter().len(), 3); |
| assert_eq!(v1.iter().collect::<Vec<_>>().len(), 3); |
| } |
| |
| #[test] |
| fn test_split_off() { |
| let mut v1 = LinkedList::new(); |
| v1.push_front(1u8); |
| v1.push_front(1u8); |
| v1.push_front(1u8); |
| v1.push_front(1u8); |
| |
| // test all splits |
| for ix in 0..1 + v1.len() { |
| let mut a = v1.clone(); |
| let b = a.split_off(ix); |
| check_links(&a); |
| check_links(&b); |
| a.extend(b); |
| assert_eq!(v1, a); |
| } |
| } |
| |
| |
| #[cfg(test)] |
| fn fuzz_test(sz: i32) { |
| let mut m: LinkedList<_> = LinkedList::new(); |
| let mut v = vec![]; |
| for i in 0..sz { |
| check_links(&m); |
| let r: u8 = thread_rng().next_u32() as u8; |
| match r % 6 { |
| 0 => { |
| m.pop_back(); |
| v.pop(); |
| } |
| 1 => { |
| if !v.is_empty() { |
| m.pop_front(); |
| v.remove(0); |
| } |
| } |
| 2 | 4 => { |
| m.push_front(-i); |
| v.insert(0, -i); |
| } |
| 3 | 5 | _ => { |
| m.push_back(i); |
| v.push(i); |
| } |
| } |
| } |
| |
| check_links(&m); |
| |
| let mut i = 0; |
| for (a, &b) in m.into_iter().zip(&v) { |
| i += 1; |
| assert_eq!(a, b); |
| } |
| assert_eq!(i, v.len()); |
| } |
| } |