0bd99f9d5c
Implement 1581 (FusedIterator) * [ ] Implement on patterns. See https://github.com/rust-lang/rust/issues/27721#issuecomment-239638642. * [ ] Handle OS Iterators. A bunch of iterators (`Args`, `Env`, etc.) in libstd wrap platform specific iterators. The current ones all appear to be well-behaved but can we assume that future ones will be? * [ ] Does someone want to audit this? On first glance, all of the iterators on which I implemented `FusedIterator` appear to be well-behaved but there are a *lot* of them so a second pair of eyes would be nice. * I haven't touched rustc internal iterators (or the internal rand) because rustc doesn't actually call `fuse()`. * `FusedIterator` can't be implemented on `std::io::{Bytes, Chars}`. Closes: #35602 (Tracking Issue) Implements: rust-lang/rfcs#1581
1398 lines
38 KiB
Rust
1398 lines
38 KiB
Rust
// Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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//! A doubly-linked list with owned nodes.
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//!
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//! The `LinkedList` allows pushing and popping elements at either end and is thus
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//! efficiently usable as a double-ended queue.
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#![stable(feature = "rust1", since = "1.0.0")]
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use alloc::boxed::{Box, IntermediateBox};
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use core::cmp::Ordering;
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use core::fmt;
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use core::hash::{Hasher, Hash};
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use core::iter::{FromIterator, FusedIterator};
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use core::marker::PhantomData;
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use core::mem;
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use core::ops::{BoxPlace, InPlace, Place, Placer};
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use core::ptr::{self, Shared};
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use super::SpecExtend;
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/// A doubly-linked list.
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#[stable(feature = "rust1", since = "1.0.0")]
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pub struct LinkedList<T> {
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head: Option<Shared<Node<T>>>,
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tail: Option<Shared<Node<T>>>,
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len: usize,
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marker: PhantomData<Box<Node<T>>>,
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}
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struct Node<T> {
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next: Option<Shared<Node<T>>>,
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prev: Option<Shared<Node<T>>>,
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element: T,
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}
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/// An iterator over references to the elements of a `LinkedList`.
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#[stable(feature = "rust1", since = "1.0.0")]
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pub struct Iter<'a, T: 'a> {
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head: Option<Shared<Node<T>>>,
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tail: Option<Shared<Node<T>>>,
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len: usize,
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marker: PhantomData<&'a Node<T>>,
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}
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// FIXME #19839: deriving is too aggressive on the bounds (T doesn't need to be Clone).
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#[stable(feature = "rust1", since = "1.0.0")]
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impl<'a, T> Clone for Iter<'a, T> {
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fn clone(&self) -> Self {
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Iter { ..*self }
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}
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}
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/// An iterator over mutable references to the elements of a `LinkedList`.
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#[stable(feature = "rust1", since = "1.0.0")]
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pub struct IterMut<'a, T: 'a> {
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list: &'a mut LinkedList<T>,
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head: Option<Shared<Node<T>>>,
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tail: Option<Shared<Node<T>>>,
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len: usize,
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}
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/// An iterator over the elements of a `LinkedList`.
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#[derive(Clone)]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub struct IntoIter<T> {
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list: LinkedList<T>,
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}
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impl<T> Node<T> {
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fn new(element: T) -> Self {
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Node {
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next: None,
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prev: None,
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element: element,
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}
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}
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fn into_element(self: Box<Self>) -> T {
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self.element
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}
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}
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// private methods
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impl<T> LinkedList<T> {
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/// Adds the given node to the front of the list.
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#[inline]
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fn push_front_node(&mut self, mut node: Box<Node<T>>) {
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unsafe {
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node.next = self.head;
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node.prev = None;
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let node = Some(Shared::new(Box::into_raw(node)));
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match self.head {
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None => self.tail = node,
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Some(head) => (**head).prev = node,
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}
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self.head = node;
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self.len += 1;
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}
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}
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/// Removes and returns the node at the front of the list.
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#[inline]
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fn pop_front_node(&mut self) -> Option<Box<Node<T>>> {
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self.head.map(|node| unsafe {
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let node = Box::from_raw(*node);
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self.head = node.next;
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match self.head {
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None => self.tail = None,
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Some(head) => (**head).prev = None,
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}
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self.len -= 1;
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node
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})
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}
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/// Adds the given node to the back of the list.
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#[inline]
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fn push_back_node(&mut self, mut node: Box<Node<T>>) {
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unsafe {
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node.next = None;
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node.prev = self.tail;
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let node = Some(Shared::new(Box::into_raw(node)));
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match self.tail {
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None => self.head = node,
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Some(tail) => (**tail).next = node,
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}
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self.tail = node;
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self.len += 1;
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}
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}
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/// Removes and returns the node at the back of the list.
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#[inline]
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fn pop_back_node(&mut self) -> Option<Box<Node<T>>> {
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self.tail.map(|node| unsafe {
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let node = Box::from_raw(*node);
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self.tail = node.prev;
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match self.tail {
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None => self.head = None,
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Some(tail) => (**tail).next = None,
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}
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self.len -= 1;
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node
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})
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}
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}
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#[stable(feature = "rust1", since = "1.0.0")]
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impl<T> Default for LinkedList<T> {
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#[inline]
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fn default() -> Self {
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Self::new()
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}
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}
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impl<T> LinkedList<T> {
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/// Creates an empty `LinkedList`.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::LinkedList;
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///
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/// let list: LinkedList<u32> = LinkedList::new();
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/// ```
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#[inline]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn new() -> Self {
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LinkedList {
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head: None,
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tail: None,
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len: 0,
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marker: PhantomData,
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}
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}
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/// Moves all elements from `other` to the end of the list.
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///
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/// This reuses all the nodes from `other` and moves them into `self`. After
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/// this operation, `other` becomes empty.
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///
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/// This operation should compute in O(1) time and O(1) memory.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::LinkedList;
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///
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/// let mut list1 = LinkedList::new();
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/// list1.push_back('a');
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///
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/// let mut list2 = LinkedList::new();
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/// list2.push_back('b');
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/// list2.push_back('c');
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///
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/// list1.append(&mut list2);
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///
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/// let mut iter = list1.iter();
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/// assert_eq!(iter.next(), Some(&'a'));
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/// assert_eq!(iter.next(), Some(&'b'));
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/// assert_eq!(iter.next(), Some(&'c'));
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/// assert!(iter.next().is_none());
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///
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/// assert!(list2.is_empty());
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn append(&mut self, other: &mut Self) {
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match self.tail {
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None => mem::swap(self, other),
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Some(tail) => if let Some(other_head) = other.head.take() {
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unsafe {
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(**tail).next = Some(other_head);
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(**other_head).prev = Some(tail);
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}
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self.tail = other.tail.take();
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self.len += mem::replace(&mut other.len, 0);
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},
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}
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}
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/// Provides a forward iterator.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::LinkedList;
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///
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/// let mut list: LinkedList<u32> = LinkedList::new();
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///
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/// list.push_back(0);
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/// list.push_back(1);
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/// list.push_back(2);
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///
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/// let mut iter = list.iter();
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/// assert_eq!(iter.next(), Some(&0));
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/// assert_eq!(iter.next(), Some(&1));
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/// assert_eq!(iter.next(), Some(&2));
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/// assert_eq!(iter.next(), None);
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/// ```
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#[inline]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn iter(&self) -> Iter<T> {
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Iter {
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head: self.head,
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tail: self.tail,
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len: self.len,
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marker: PhantomData,
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}
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}
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/// Provides a forward iterator with mutable references.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::LinkedList;
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///
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/// let mut list: LinkedList<u32> = LinkedList::new();
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///
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/// list.push_back(0);
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/// list.push_back(1);
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/// list.push_back(2);
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///
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/// for element in list.iter_mut() {
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/// *element += 10;
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/// }
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///
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/// let mut iter = list.iter();
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/// assert_eq!(iter.next(), Some(&10));
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/// assert_eq!(iter.next(), Some(&11));
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/// assert_eq!(iter.next(), Some(&12));
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/// assert_eq!(iter.next(), None);
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/// ```
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#[inline]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn iter_mut(&mut self) -> IterMut<T> {
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IterMut {
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head: self.head,
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tail: self.tail,
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len: self.len,
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list: self,
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}
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}
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/// Returns `true` if the `LinkedList` is empty.
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///
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/// This operation should compute in O(1) time.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::LinkedList;
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///
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/// let mut dl = LinkedList::new();
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/// assert!(dl.is_empty());
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///
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/// dl.push_front("foo");
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/// assert!(!dl.is_empty());
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/// ```
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#[inline]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn is_empty(&self) -> bool {
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self.head.is_none()
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}
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/// Returns the length of the `LinkedList`.
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///
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/// This operation should compute in O(1) time.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::LinkedList;
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///
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/// let mut dl = LinkedList::new();
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///
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/// dl.push_front(2);
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/// assert_eq!(dl.len(), 1);
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///
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/// dl.push_front(1);
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/// assert_eq!(dl.len(), 2);
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///
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/// dl.push_back(3);
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/// assert_eq!(dl.len(), 3);
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/// ```
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#[inline]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn len(&self) -> usize {
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self.len
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}
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/// Removes all elements from the `LinkedList`.
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///
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/// This operation should compute in O(n) time.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::LinkedList;
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///
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/// let mut dl = LinkedList::new();
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///
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/// dl.push_front(2);
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/// dl.push_front(1);
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/// assert_eq!(dl.len(), 2);
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/// assert_eq!(dl.front(), Some(&1));
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///
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/// dl.clear();
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/// assert_eq!(dl.len(), 0);
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/// assert_eq!(dl.front(), None);
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/// ```
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#[inline]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn clear(&mut self) {
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*self = Self::new();
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}
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/// Returns `true` if the `LinkedList` contains an element equal to the
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/// given value.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::LinkedList;
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///
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/// let mut list: LinkedList<u32> = LinkedList::new();
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///
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/// list.push_back(0);
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/// list.push_back(1);
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/// list.push_back(2);
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///
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/// assert_eq!(list.contains(&0), true);
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/// assert_eq!(list.contains(&10), false);
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/// ```
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#[stable(feature = "linked_list_contains", since = "1.12.0")]
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pub fn contains(&self, x: &T) -> bool
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where T: PartialEq<T>
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{
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self.iter().any(|e| e == x)
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}
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/// Provides a reference to the front element, or `None` if the list is
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/// empty.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::LinkedList;
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///
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/// let mut dl = LinkedList::new();
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/// assert_eq!(dl.front(), None);
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///
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/// dl.push_front(1);
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/// assert_eq!(dl.front(), Some(&1));
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/// ```
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#[inline]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn front(&self) -> Option<&T> {
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self.head.map(|node| unsafe { &(**node).element })
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}
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/// Provides a mutable reference to the front element, or `None` if the list
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/// is empty.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::LinkedList;
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///
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/// let mut dl = LinkedList::new();
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/// assert_eq!(dl.front(), None);
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///
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/// dl.push_front(1);
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/// assert_eq!(dl.front(), Some(&1));
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///
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/// match dl.front_mut() {
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/// None => {},
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/// Some(x) => *x = 5,
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/// }
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/// assert_eq!(dl.front(), Some(&5));
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/// ```
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#[inline]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn front_mut(&mut self) -> Option<&mut T> {
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self.head.map(|node| unsafe { &mut (**node).element })
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}
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/// Provides a reference to the back element, or `None` if the list is
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/// empty.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::LinkedList;
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///
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/// let mut dl = LinkedList::new();
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/// assert_eq!(dl.back(), None);
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///
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/// dl.push_back(1);
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/// assert_eq!(dl.back(), Some(&1));
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/// ```
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#[inline]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn back(&self) -> Option<&T> {
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self.tail.map(|node| unsafe { &(**node).element })
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}
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/// Provides a mutable reference to the back element, or `None` if the list
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/// is empty.
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///
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/// # Examples
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///
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/// ```
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/// use std::collections::LinkedList;
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///
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/// let mut dl = LinkedList::new();
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/// assert_eq!(dl.back(), None);
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///
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/// dl.push_back(1);
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/// assert_eq!(dl.back(), Some(&1));
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///
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/// match dl.back_mut() {
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/// None => {},
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/// Some(x) => *x = 5,
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/// }
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/// assert_eq!(dl.back(), Some(&5));
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/// ```
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#[inline]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn back_mut(&mut self) -> Option<&mut T> {
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self.tail.map(|node| unsafe { &mut (**node).element })
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}
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|
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/// Adds an element first in the list.
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///
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|
/// This operation should compute in O(1) time.
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|
///
|
|
/// # Examples
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|
///
|
|
/// ```
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/// use std::collections::LinkedList;
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///
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/// let mut dl = LinkedList::new();
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///
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/// dl.push_front(2);
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/// assert_eq!(dl.front().unwrap(), &2);
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///
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/// dl.push_front(1);
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/// assert_eq!(dl.front().unwrap(), &1);
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
|
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pub fn push_front(&mut self, elt: T) {
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self.push_front_node(box Node::new(elt));
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}
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|
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/// Removes the first element and returns it, or `None` if the list is
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/// empty.
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///
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|
/// This operation should compute in O(1) time.
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///
|
|
/// # Examples
|
|
///
|
|
/// ```
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/// use std::collections::LinkedList;
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///
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/// let mut d = LinkedList::new();
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/// assert_eq!(d.pop_front(), None);
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///
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/// d.push_front(1);
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/// d.push_front(3);
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/// assert_eq!(d.pop_front(), Some(3));
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/// assert_eq!(d.pop_front(), Some(1));
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/// assert_eq!(d.pop_front(), None);
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn pop_front(&mut self) -> Option<T> {
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|
self.pop_front_node().map(Node::into_element)
|
|
}
|
|
|
|
/// 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(Node::into_element)
|
|
}
|
|
|
|
/// 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, Self::new());
|
|
} else if at == len {
|
|
return Self::new();
|
|
}
|
|
|
|
// Below, we iterate towards the `i-1`th node, either from the start or the end,
|
|
// depending on which would be faster.
|
|
let 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 second_part_head;
|
|
|
|
unsafe {
|
|
second_part_head = (**split_node.unwrap()).next.take();
|
|
if let Some(head) = second_part_head {
|
|
(**head).prev = None;
|
|
}
|
|
}
|
|
|
|
let second_part = LinkedList {
|
|
head: second_part_head,
|
|
tail: self.tail,
|
|
len: len - at,
|
|
marker: PhantomData,
|
|
};
|
|
|
|
// Fix the tail ptr of the first part
|
|
self.tail = split_node;
|
|
self.len = at;
|
|
|
|
second_part
|
|
}
|
|
|
|
/// Returns a place for insertion at the front of the list.
|
|
///
|
|
/// Using this method with placement syntax is equivalent to [`push_front`]
|
|
/// (#method.push_front), but may be more efficient.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// #![feature(collection_placement)]
|
|
/// #![feature(placement_in_syntax)]
|
|
///
|
|
/// use std::collections::LinkedList;
|
|
///
|
|
/// let mut list = LinkedList::new();
|
|
/// list.front_place() <- 2;
|
|
/// list.front_place() <- 4;
|
|
/// assert!(list.iter().eq(&[4, 2]));
|
|
/// ```
|
|
#[unstable(feature = "collection_placement",
|
|
reason = "method name and placement protocol are subject to change",
|
|
issue = "30172")]
|
|
pub fn front_place(&mut self) -> FrontPlace<T> {
|
|
FrontPlace { list: self, node: IntermediateBox::make_place() }
|
|
}
|
|
|
|
/// Returns a place for insertion at the back of the list.
|
|
///
|
|
/// Using this method with placement syntax is equivalent to [`push_back`](#method.push_back),
|
|
/// but may be more efficient.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// #![feature(collection_placement)]
|
|
/// #![feature(placement_in_syntax)]
|
|
///
|
|
/// use std::collections::LinkedList;
|
|
///
|
|
/// let mut list = LinkedList::new();
|
|
/// list.back_place() <- 2;
|
|
/// list.back_place() <- 4;
|
|
/// assert!(list.iter().eq(&[2, 4]));
|
|
/// ```
|
|
#[unstable(feature = "collection_placement",
|
|
reason = "method name and placement protocol are subject to change",
|
|
issue = "30172")]
|
|
pub fn back_place(&mut self) -> BackPlace<T> {
|
|
BackPlace { list: self, node: IntermediateBox::make_place() }
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T> Drop for LinkedList<T> {
|
|
#[unsafe_destructor_blind_to_params]
|
|
fn drop(&mut self) {
|
|
while let Some(_) = self.pop_front_node() {}
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a, T> Iterator for Iter<'a, T> {
|
|
type Item = &'a T;
|
|
|
|
#[inline]
|
|
fn next(&mut self) -> Option<&'a T> {
|
|
if self.len == 0 {
|
|
None
|
|
} else {
|
|
self.head.map(|node| unsafe {
|
|
let node = &**node;
|
|
self.len -= 1;
|
|
self.head = node.next;
|
|
&node.element
|
|
})
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
fn size_hint(&self) -> (usize, Option<usize>) {
|
|
(self.len, Some(self.len))
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a, T> DoubleEndedIterator for Iter<'a, T> {
|
|
#[inline]
|
|
fn next_back(&mut self) -> Option<&'a T> {
|
|
if self.len == 0 {
|
|
None
|
|
} else {
|
|
self.tail.map(|node| unsafe {
|
|
let node = &**node;
|
|
self.len -= 1;
|
|
self.tail = node.prev;
|
|
&node.element
|
|
})
|
|
}
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a, T> ExactSizeIterator for Iter<'a, T> {}
|
|
|
|
#[unstable(feature = "fused", issue = "35602")]
|
|
impl<'a, T> FusedIterator for Iter<'a, T> {}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a, T> Iterator for IterMut<'a, T> {
|
|
type Item = &'a mut T;
|
|
|
|
#[inline]
|
|
fn next(&mut self) -> Option<&'a mut T> {
|
|
if self.len == 0 {
|
|
None
|
|
} else {
|
|
self.head.map(|node| unsafe {
|
|
let node = &mut **node;
|
|
self.len -= 1;
|
|
self.head = node.next;
|
|
&mut node.element
|
|
})
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
fn size_hint(&self) -> (usize, Option<usize>) {
|
|
(self.len, Some(self.len))
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a, T> DoubleEndedIterator for IterMut<'a, T> {
|
|
#[inline]
|
|
fn next_back(&mut self) -> Option<&'a mut T> {
|
|
if self.len == 0 {
|
|
None
|
|
} else {
|
|
self.tail.map(|node| unsafe {
|
|
let node = &mut **node;
|
|
self.len -= 1;
|
|
self.tail = node.prev;
|
|
&mut node.element
|
|
})
|
|
}
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a, T> ExactSizeIterator for IterMut<'a, T> {}
|
|
|
|
#[unstable(feature = "fused", issue = "35602")]
|
|
impl<'a, T> FusedIterator for IterMut<'a, T> {}
|
|
|
|
impl<'a, T> IterMut<'a, T> {
|
|
/// Inserts the given element 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, element: T) {
|
|
match self.head {
|
|
None => self.list.push_back(element),
|
|
Some(head) => unsafe {
|
|
let prev = match (**head).prev {
|
|
None => return self.list.push_front(element),
|
|
Some(prev) => prev,
|
|
};
|
|
|
|
let node = Some(Shared::new(Box::into_raw(box Node {
|
|
next: Some(head),
|
|
prev: Some(prev),
|
|
element: element,
|
|
})));
|
|
|
|
(**prev).next = node;
|
|
(**head).prev = node;
|
|
|
|
self.list.len += 1;
|
|
}
|
|
}
|
|
}
|
|
|
|
/// 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 T> {
|
|
if self.len == 0 {
|
|
None
|
|
} else {
|
|
self.head.map(|node| unsafe { &mut (**node).element })
|
|
}
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T> Iterator for IntoIter<T> {
|
|
type Item = T;
|
|
|
|
#[inline]
|
|
fn next(&mut self) -> Option<T> {
|
|
self.list.pop_front()
|
|
}
|
|
|
|
#[inline]
|
|
fn size_hint(&self) -> (usize, Option<usize>) {
|
|
(self.list.len, Some(self.list.len))
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T> DoubleEndedIterator for IntoIter<T> {
|
|
#[inline]
|
|
fn next_back(&mut self) -> Option<T> {
|
|
self.list.pop_back()
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T> ExactSizeIterator for IntoIter<T> {}
|
|
|
|
#[unstable(feature = "fused", issue = "35602")]
|
|
impl<T> FusedIterator for IntoIter<T> {}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T> FromIterator<T> for LinkedList<T> {
|
|
fn from_iter<I: IntoIterator<Item = T>>(iter: I) -> Self {
|
|
let mut list = Self::new();
|
|
list.extend(iter);
|
|
list
|
|
}
|
|
}
|
|
|
|
#[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(self) -> IterMut<'a, T> {
|
|
self.iter_mut()
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T> Extend<T> for LinkedList<T> {
|
|
fn extend<I: IntoIterator<Item = T>>(&mut self, iter: I) {
|
|
<Self as SpecExtend<I>>::spec_extend(self, iter);
|
|
}
|
|
}
|
|
|
|
impl<I: IntoIterator> SpecExtend<I> for LinkedList<I::Item> {
|
|
default fn spec_extend(&mut self, iter: I) {
|
|
for elt in iter {
|
|
self.push_back(elt);
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<T> SpecExtend<LinkedList<T>> for LinkedList<T> {
|
|
fn spec_extend(&mut self, ref mut other: LinkedList<T>) {
|
|
self.append(other);
|
|
}
|
|
}
|
|
|
|
#[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<T: PartialEq> PartialEq for LinkedList<T> {
|
|
fn eq(&self, other: &Self) -> bool {
|
|
self.len() == other.len() && self.iter().eq(other)
|
|
}
|
|
|
|
fn ne(&self, other: &Self) -> bool {
|
|
self.len() != other.len() || self.iter().ne(other)
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T: Eq> Eq for LinkedList<T> {}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T: PartialOrd> PartialOrd for LinkedList<T> {
|
|
fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
|
|
self.iter().partial_cmp(other)
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T: Ord> Ord for LinkedList<T> {
|
|
#[inline]
|
|
fn cmp(&self, other: &Self) -> Ordering {
|
|
self.iter().cmp(other)
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T: Clone> Clone for LinkedList<T> {
|
|
fn clone(&self) -> Self {
|
|
self.iter().cloned().collect()
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T: fmt::Debug> fmt::Debug for LinkedList<T> {
|
|
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
|
|
f.debug_list().entries(self).finish()
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<T: Hash> Hash for LinkedList<T> {
|
|
fn hash<H: Hasher>(&self, state: &mut H) {
|
|
self.len().hash(state);
|
|
for elt in self {
|
|
elt.hash(state);
|
|
}
|
|
}
|
|
}
|
|
|
|
unsafe fn finalize<T>(node: IntermediateBox<Node<T>>) -> Box<Node<T>> {
|
|
let mut node = node.finalize();
|
|
ptr::write(&mut node.next, None);
|
|
ptr::write(&mut node.prev, None);
|
|
node
|
|
}
|
|
|
|
/// A place for insertion at the front of a `LinkedList`.
|
|
///
|
|
/// See [`LinkedList::front_place`](struct.LinkedList.html#method.front_place) for details.
|
|
#[must_use = "places do nothing unless written to with `<-` syntax"]
|
|
#[unstable(feature = "collection_placement",
|
|
reason = "struct name and placement protocol are subject to change",
|
|
issue = "30172")]
|
|
pub struct FrontPlace<'a, T: 'a> {
|
|
list: &'a mut LinkedList<T>,
|
|
node: IntermediateBox<Node<T>>,
|
|
}
|
|
|
|
#[unstable(feature = "collection_placement",
|
|
reason = "placement protocol is subject to change",
|
|
issue = "30172")]
|
|
impl<'a, T> Placer<T> for FrontPlace<'a, T> {
|
|
type Place = Self;
|
|
|
|
fn make_place(self) -> Self {
|
|
self
|
|
}
|
|
}
|
|
|
|
#[unstable(feature = "collection_placement",
|
|
reason = "placement protocol is subject to change",
|
|
issue = "30172")]
|
|
impl<'a, T> Place<T> for FrontPlace<'a, T> {
|
|
fn pointer(&mut self) -> *mut T {
|
|
unsafe { &mut (*self.node.pointer()).element }
|
|
}
|
|
}
|
|
|
|
#[unstable(feature = "collection_placement",
|
|
reason = "placement protocol is subject to change",
|
|
issue = "30172")]
|
|
impl<'a, T> InPlace<T> for FrontPlace<'a, T> {
|
|
type Owner = ();
|
|
|
|
unsafe fn finalize(self) {
|
|
let FrontPlace { list, node } = self;
|
|
list.push_front_node(finalize(node));
|
|
}
|
|
}
|
|
|
|
/// A place for insertion at the back of a `LinkedList`.
|
|
///
|
|
/// See [`LinkedList::back_place`](struct.LinkedList.html#method.back_place) for details.
|
|
#[must_use = "places do nothing unless written to with `<-` syntax"]
|
|
#[unstable(feature = "collection_placement",
|
|
reason = "struct name and placement protocol are subject to change",
|
|
issue = "30172")]
|
|
pub struct BackPlace<'a, T: 'a> {
|
|
list: &'a mut LinkedList<T>,
|
|
node: IntermediateBox<Node<T>>,
|
|
}
|
|
|
|
#[unstable(feature = "collection_placement",
|
|
reason = "placement protocol is subject to change",
|
|
issue = "30172")]
|
|
impl<'a, T> Placer<T> for BackPlace<'a, T> {
|
|
type Place = Self;
|
|
|
|
fn make_place(self) -> Self {
|
|
self
|
|
}
|
|
}
|
|
|
|
#[unstable(feature = "collection_placement",
|
|
reason = "placement protocol is subject to change",
|
|
issue = "30172")]
|
|
impl<'a, T> Place<T> for BackPlace<'a, T> {
|
|
fn pointer(&mut self) -> *mut T {
|
|
unsafe { &mut (*self.node.pointer()).element }
|
|
}
|
|
}
|
|
|
|
#[unstable(feature = "collection_placement",
|
|
reason = "placement protocol is subject to change",
|
|
issue = "30172")]
|
|
impl<'a, T> InPlace<T> for BackPlace<'a, T> {
|
|
type Owner = ();
|
|
|
|
unsafe fn finalize(self) {
|
|
let BackPlace { list, node } = self;
|
|
list.push_back_node(finalize(node));
|
|
}
|
|
}
|
|
|
|
// 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 }
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
unsafe impl<T: Send> Send for LinkedList<T> {}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
unsafe impl<T: Sync> Sync for LinkedList<T> {}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
unsafe impl<'a, T: Sync> Send for Iter<'a, T> {}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
unsafe impl<'a, T: Sync> Sync for Iter<'a, T> {}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
unsafe impl<'a, T: Send> Send for IterMut<'a, T> {}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
unsafe impl<'a, T: Sync> Sync for IterMut<'a, T> {}
|
|
|
|
#[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>) {
|
|
unsafe {
|
|
let mut len = 0;
|
|
let mut last_ptr: Option<&Node<T>> = None;
|
|
let mut node_ptr: &Node<T>;
|
|
match list.head {
|
|
None => {
|
|
assert_eq!(0, list.len);
|
|
return;
|
|
}
|
|
Some(node) => node_ptr = &**node,
|
|
}
|
|
loop {
|
|
match (last_ptr, node_ptr.prev) {
|
|
(None, None) => {}
|
|
(None, _) => panic!("prev link for 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(next) => {
|
|
last_ptr = Some(node_ptr);
|
|
node_ptr = &**next;
|
|
len += 1;
|
|
}
|
|
None => {
|
|
len += 1;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
assert_eq!(len, list.len);
|
|
}
|
|
}
|
|
|
|
#[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.extend_from_slice(&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(1);
|
|
v1.push_front(1);
|
|
v1.push_front(1);
|
|
v1.push_front(1);
|
|
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(1);
|
|
v1.push_front(1);
|
|
v1.push_front(1);
|
|
v1.push_front(1);
|
|
|
|
// 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());
|
|
}
|
|
}
|