2918 lines
84 KiB
Rust
2918 lines
84 KiB
Rust
// Copyright 2013 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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/*!
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Composable external iterators
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# The `Iterator` trait
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This module defines Rust's core iteration trait. The `Iterator` trait has one
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un-implemented method, `next`. All other methods are derived through default
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methods to perform operations such as `zip`, `chain`, `enumerate`, and `fold`.
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The goal of this module is to unify iteration across all containers in Rust.
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An iterator can be considered as a state machine which is used to track which
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element will be yielded next.
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There are various extensions also defined in this module to assist with various
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types of iteration, such as the `DoubleEndedIterator` for iterating in reverse,
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the `FromIterator` trait for creating a container from an iterator, and much
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more.
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## Rust's `for` loop
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The special syntax used by rust's `for` loop is based around the `Iterator`
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trait defined in this module. For loops can be viewed as a syntactical expansion
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into a `loop`, for example, the `for` loop in this example is essentially
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translated to the `loop` below.
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```rust
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let values = ~[1, 2, 3];
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// "Syntactical sugar" taking advantage of an iterator
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for &x in values.iter() {
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println!("{}", x);
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}
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// Rough translation of the iteration without a `for` iterator.
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let mut it = values.iter();
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loop {
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match it.next() {
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Some(&x) => {
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println!("{}", x);
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}
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None => { break }
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}
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}
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```
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This `for` loop syntax can be applied to any iterator over any type.
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## Iteration protocol and more
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More detailed information about iterators can be found in the [container
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tutorial](http://static.rust-lang.org/doc/master/tutorial-container.html) with
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the rest of the rust manuals.
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*/
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use cmp;
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use num::{Zero, One, Integer, CheckedAdd, CheckedSub, Saturating, ToPrimitive};
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use option::{Option, Some, None};
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use ops::{Add, Mul, Sub};
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use cmp::{Eq, Ord};
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use clone::Clone;
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use uint;
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use util;
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/// Conversion from an `Iterator`
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pub trait FromIterator<A> {
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/// Build a container with elements from an external iterator.
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fn from_iterator<T: Iterator<A>>(iterator: &mut T) -> Self;
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}
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/// A type growable from an `Iterator` implementation
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pub trait Extendable<A>: FromIterator<A> {
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/// Extend a container with the elements yielded by an iterator
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fn extend<T: Iterator<A>>(&mut self, iterator: &mut T);
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}
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/// An interface for dealing with "external iterators". These types of iterators
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/// can be resumed at any time as all state is stored internally as opposed to
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/// being located on the call stack.
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///
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/// The Iterator protocol states that an iterator yields a (potentially-empty,
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/// potentially-infinite) sequence of values, and returns `None` to signal that
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/// it's finished. The Iterator protocol does not define behavior after `None`
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/// is returned. A concrete Iterator implementation may choose to behave however
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/// it wishes, either by returning `None` infinitely, or by doing something
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/// else.
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pub trait Iterator<A> {
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/// Advance the iterator and return the next value. Return `None` when the end is reached.
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fn next(&mut self) -> Option<A>;
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/// Return a lower bound and upper bound on the remaining length of the iterator.
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///
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/// The common use case for the estimate is pre-allocating space to store the results.
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#[inline]
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fn size_hint(&self) -> (uint, Option<uint>) { (0, None) }
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/// Chain this iterator with another, returning a new iterator which will
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/// finish iterating over the current iterator, and then it will iterate
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/// over the other specified iterator.
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///
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/// # Example
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///
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/// ```rust
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/// let a = [0];
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/// let b = [1];
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/// let mut it = a.iter().chain(b.iter());
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/// assert_eq!(it.next().unwrap(), &0);
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/// assert_eq!(it.next().unwrap(), &1);
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/// assert!(it.next().is_none());
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/// ```
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#[inline]
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fn chain<U: Iterator<A>>(self, other: U) -> Chain<Self, U> {
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Chain{a: self, b: other, flag: false}
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}
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/// Creates an iterator which iterates over both this and the specified
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/// iterators simultaneously, yielding the two elements as pairs. When
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/// either iterator returns None, all further invocations of next() will
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/// return None.
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///
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/// # Example
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///
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/// ```rust
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/// let a = [0];
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/// let b = [1];
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/// let mut it = a.iter().zip(b.iter());
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/// assert_eq!(it.next().unwrap(), (&0, &1));
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/// assert!(it.next().is_none());
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/// ```
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#[inline]
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fn zip<B, U: Iterator<B>>(self, other: U) -> Zip<Self, U> {
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Zip{a: self, b: other}
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}
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/// Creates a new iterator which will apply the specified function to each
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/// element returned by the first, yielding the mapped element instead.
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///
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/// # Example
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///
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/// ```rust
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/// let a = [1, 2];
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/// let mut it = a.iter().map(|&x| 2 * x);
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/// assert_eq!(it.next().unwrap(), 2);
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/// assert_eq!(it.next().unwrap(), 4);
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/// assert!(it.next().is_none());
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/// ```
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#[inline]
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fn map<'r, B>(self, f: 'r |A| -> B) -> Map<'r, A, B, Self> {
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Map{iter: self, f: f}
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}
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/// Creates an iterator which applies the predicate to each element returned
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/// by this iterator. Only elements which have the predicate evaluate to
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/// `true` will be yielded.
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///
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/// # Example
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///
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/// ```rust
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/// let a = [1, 2];
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/// let mut it = a.iter().filter(|&x| *x > 1);
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/// assert_eq!(it.next().unwrap(), &2);
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/// assert!(it.next().is_none());
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/// ```
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#[inline]
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fn filter<'r>(self, predicate: 'r |&A| -> bool) -> Filter<'r, A, Self> {
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Filter{iter: self, predicate: predicate}
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}
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/// Creates an iterator which both filters and maps elements.
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/// If the specified function returns None, the element is skipped.
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/// Otherwise the option is unwrapped and the new value is yielded.
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///
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/// # Example
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///
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/// ```rust
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/// let a = [1, 2];
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/// let mut it = a.iter().filter_map(|&x| if x > 1 {Some(2 * x)} else {None});
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/// assert_eq!(it.next().unwrap(), 4);
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/// assert!(it.next().is_none());
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/// ```
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#[inline]
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fn filter_map<'r, B>(self, f: 'r |A| -> Option<B>) -> FilterMap<'r, A, B, Self> {
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FilterMap { iter: self, f: f }
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}
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/// Creates an iterator which yields a pair of the value returned by this
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/// iterator plus the current index of iteration.
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///
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/// # Example
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///
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/// ```rust
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/// let a = [100, 200];
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/// let mut it = a.iter().enumerate();
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/// assert_eq!(it.next().unwrap(), (0, &100));
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/// assert_eq!(it.next().unwrap(), (1, &200));
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/// assert!(it.next().is_none());
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/// ```
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#[inline]
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fn enumerate(self) -> Enumerate<Self> {
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Enumerate{iter: self, count: 0}
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}
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/// Creates an iterator that has a `.peek()` method
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/// that returns a optional reference to the next element.
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///
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/// # Example
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///
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/// ```rust
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/// let a = [100, 200, 300];
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/// let mut it = xs.iter().map(|&x|x).peekable();
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/// assert_eq!(it.peek().unwrap(), &100);
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/// assert_eq!(it.next().unwrap(), 100);
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/// assert_eq!(it.next().unwrap(), 200);
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/// assert_eq!(it.peek().unwrap(), &300);
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/// assert_eq!(it.peek().unwrap(), &300);
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/// assert_eq!(it.next().unwrap(), 300);
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/// assert!(it.peek().is_none());
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/// assert!(it.next().is_none());
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/// ```
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#[inline]
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fn peekable(self) -> Peekable<A, Self> {
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Peekable{iter: self, peeked: None}
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}
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/// Creates an iterator which invokes the predicate on elements until it
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/// returns false. Once the predicate returns false, all further elements are
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/// yielded.
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///
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/// # Example
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///
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/// ```rust
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/// let a = [1, 2, 3, 2, 1];
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/// let mut it = a.iter().skip_while(|&a| *a < 3);
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/// assert_eq!(it.next().unwrap(), &3);
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/// assert_eq!(it.next().unwrap(), &2);
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/// assert_eq!(it.next().unwrap(), &1);
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/// assert!(it.next().is_none());
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/// ```
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#[inline]
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fn skip_while<'r>(self, predicate: 'r |&A| -> bool) -> SkipWhile<'r, A, Self> {
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SkipWhile{iter: self, flag: false, predicate: predicate}
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}
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/// Creates an iterator which yields elements so long as the predicate
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/// returns true. After the predicate returns false for the first time, no
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/// further elements will be yielded.
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///
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/// # Example
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///
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/// ```rust
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/// let a = [1, 2, 3, 2, 1];
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/// let mut it = a.iter().take_while(|&a| *a < 3);
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/// assert_eq!(it.next().unwrap(), &1);
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/// assert_eq!(it.next().unwrap(), &2);
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/// assert!(it.next().is_none());
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/// ```
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#[inline]
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fn take_while<'r>(self, predicate: 'r |&A| -> bool) -> TakeWhile<'r, A, Self> {
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TakeWhile{iter: self, flag: false, predicate: predicate}
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}
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/// Creates an iterator which skips the first `n` elements of this iterator,
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/// and then it yields all further items.
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///
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/// # Example
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///
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/// ```rust
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/// let a = [1, 2, 3, 4, 5];
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/// let mut it = a.iter().skip(3);
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/// assert_eq!(it.next().unwrap(), &4);
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/// assert_eq!(it.next().unwrap(), &5);
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/// assert!(it.next().is_none());
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/// ```
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#[inline]
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fn skip(self, n: uint) -> Skip<Self> {
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Skip{iter: self, n: n}
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}
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/// Creates an iterator which yields the first `n` elements of this
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/// iterator, and then it will always return None.
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///
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/// # Example
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///
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/// ```rust
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/// let a = [1, 2, 3, 4, 5];
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/// let mut it = a.iter().take(3);
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/// assert_eq!(it.next().unwrap(), &1);
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/// assert_eq!(it.next().unwrap(), &2);
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/// assert_eq!(it.next().unwrap(), &3);
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/// assert!(it.next().is_none());
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/// ```
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#[inline]
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fn take(self, n: uint) -> Take<Self> {
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Take{iter: self, n: n}
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}
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/// Creates a new iterator which behaves in a similar fashion to foldl.
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/// There is a state which is passed between each iteration and can be
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/// mutated as necessary. The yielded values from the closure are yielded
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/// from the Scan instance when not None.
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///
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/// # Example
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///
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/// ```rust
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/// let a = [1, 2, 3, 4, 5];
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/// let mut it = a.iter().scan(1, |fac, &x| {
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/// *fac = *fac * x;
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/// Some(*fac)
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/// });
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/// assert_eq!(it.next().unwrap(), 1);
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/// assert_eq!(it.next().unwrap(), 2);
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/// assert_eq!(it.next().unwrap(), 6);
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/// assert_eq!(it.next().unwrap(), 24);
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/// assert_eq!(it.next().unwrap(), 120);
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/// assert!(it.next().is_none());
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/// ```
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#[inline]
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fn scan<'r, St, B>(self, initial_state: St, f: 'r |&mut St, A| -> Option<B>)
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-> Scan<'r, A, B, Self, St> {
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Scan{iter: self, f: f, state: initial_state}
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}
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/// Creates an iterator that maps each element to an iterator,
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/// and yields the elements of the produced iterators
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///
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/// # Example
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///
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/// ```rust
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/// let xs = [2u, 3];
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/// let ys = [0u, 1, 0, 1, 2];
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/// let mut it = xs.iter().flat_map(|&x| count(0u, 1).take(x));
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/// // Check that `it` has the same elements as `ys`
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/// let mut i = 0;
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/// for x: uint in it {
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/// assert_eq!(x, ys[i]);
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/// i += 1;
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/// }
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/// ```
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#[inline]
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fn flat_map<'r, B, U: Iterator<B>>(self, f: 'r |A| -> U)
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-> FlatMap<'r, A, Self, U> {
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FlatMap{iter: self, f: f, frontiter: None, backiter: None }
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}
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/// Creates an iterator that yields `None` forever after the underlying
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/// iterator yields `None`. Random-access iterator behavior is not
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/// affected, only single and double-ended iterator behavior.
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///
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/// # Example
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///
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/// ```rust
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/// fn process<U: Iterator<int>>(it: U) -> int {
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/// let mut it = it.fuse();
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/// let mut sum = 0;
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/// for x in it {
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/// if x > 5 {
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/// break;
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/// }
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/// sum += x;
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/// }
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/// // did we exhaust the iterator?
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/// if it.next().is_none() {
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/// sum += 1000;
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/// }
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/// sum
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/// }
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/// let x = ~[1,2,3,7,8,9];
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/// assert_eq!(process(x.move_iter()), 1006);
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/// ```
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#[inline]
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fn fuse(self) -> Fuse<Self> {
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Fuse{iter: self, done: false}
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}
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/// Creates an iterator that calls a function with a reference to each
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/// element before yielding it. This is often useful for debugging an
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/// iterator pipeline.
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///
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/// # Example
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///
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/// ```rust
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///let xs = [1u, 4, 2, 3, 8, 9, 6];
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///let sum = xs.iter()
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/// .map(|&x| x)
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/// .inspect(|&x| debug!("filtering %u", x))
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/// .filter(|&x| x % 2 == 0)
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/// .inspect(|&x| debug!("%u made it through", x))
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/// .sum();
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///println(sum.to_str());
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/// ```
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#[inline]
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fn inspect<'r>(self, f: 'r |&A|) -> Inspect<'r, A, Self> {
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Inspect{iter: self, f: f}
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}
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/// Creates a wrapper around a mutable reference to the iterator.
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///
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/// This is useful to allow applying iterator adaptors while still
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/// retaining ownership of the original iterator value.
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///
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/// # Example
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///
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/// ```rust
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/// let mut xs = range(0, 10);
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/// // sum the first five values
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/// let partial_sum = xs.by_ref().take(5).fold(0, |a, b| a + b);
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/// assert!(partial_sum == 10);
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/// // xs.next() is now `5`
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/// assert!(xs.next() == Some(5));
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/// ```
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fn by_ref<'r>(&'r mut self) -> ByRef<'r, Self> {
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ByRef{iter: self}
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}
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/// Apply a function to each element, or stop iterating if the
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/// function returns `false`.
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///
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/// # Example
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///
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/// ```rust
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/// range(0, 5).advance(|x| {print!("{} ", x); true});
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/// ```
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#[inline]
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fn advance(&mut self, f: |A| -> bool) -> bool {
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loop {
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match self.next() {
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Some(x) => {
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if !f(x) { return false; }
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}
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None => { return true; }
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}
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}
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}
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/// Loops through the entire iterator, collecting all of the elements into
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/// a container implementing `FromIterator`.
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///
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/// # Example
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///
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/// ```rust
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/// let a = [1, 2, 3, 4, 5];
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/// let b: ~[int] = a.iter().map(|&x| x).collect();
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/// assert!(a == b);
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/// ```
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#[inline]
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fn collect<B: FromIterator<A>>(&mut self) -> B {
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FromIterator::from_iterator(self)
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}
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/// Loops through the entire iterator, collecting all of the elements into
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/// a unique vector. This is simply collect() specialized for vectors.
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///
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/// # Example
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///
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/// ```rust
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/// let a = [1, 2, 3, 4, 5];
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/// let b: ~[int] = a.iter().map(|&x| x).to_owned_vec();
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/// assert!(a == b);
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/// ```
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#[inline]
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fn to_owned_vec(&mut self) -> ~[A] {
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self.collect()
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}
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/// Loops through `n` iterations, returning the `n`th element of the
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/// iterator.
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///
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/// # Example
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///
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/// ```rust
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/// let a = [1, 2, 3, 4, 5];
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/// let mut it = a.iter();
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/// assert!(it.nth(2).unwrap() == &3);
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/// assert!(it.nth(2) == None);
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/// ```
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#[inline]
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fn nth(&mut self, mut n: uint) -> Option<A> {
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loop {
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match self.next() {
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Some(x) => if n == 0 { return Some(x) },
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None => return None
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}
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n -= 1;
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}
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}
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/// Loops through the entire iterator, returning the last element of the
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/// iterator.
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///
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/// # Example
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///
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/// ```rust
|
|
/// let a = [1, 2, 3, 4, 5];
|
|
/// assert!(a.iter().last().unwrap() == &5);
|
|
/// ```
|
|
#[inline]
|
|
fn last(&mut self) -> Option<A> {
|
|
let mut last = None;
|
|
for x in *self { last = Some(x); }
|
|
last
|
|
}
|
|
|
|
/// Performs a fold operation over the entire iterator, returning the
|
|
/// eventual state at the end of the iteration.
|
|
///
|
|
/// # Example
|
|
///
|
|
/// ```rust
|
|
/// let a = [1, 2, 3, 4, 5];
|
|
/// assert!(a.iter().fold(0, |a, &b| a + b) == 15);
|
|
/// ```
|
|
#[inline]
|
|
fn fold<B>(&mut self, init: B, f: |B, A| -> B) -> B {
|
|
let mut accum = init;
|
|
loop {
|
|
match self.next() {
|
|
Some(x) => { accum = f(accum, x); }
|
|
None => { break; }
|
|
}
|
|
}
|
|
accum
|
|
}
|
|
|
|
/// Counts the number of elements in this iterator.
|
|
///
|
|
/// # Example
|
|
///
|
|
/// ```rust
|
|
/// let a = [1, 2, 3, 4, 5];
|
|
/// let mut it = a.iter();
|
|
/// assert!(it.len() == 5);
|
|
/// assert!(it.len() == 0);
|
|
/// ```
|
|
#[inline]
|
|
fn len(&mut self) -> uint {
|
|
self.fold(0, |cnt, _x| cnt + 1)
|
|
}
|
|
|
|
/// Tests whether the predicate holds true for all elements in the iterator.
|
|
///
|
|
/// # Example
|
|
///
|
|
/// ```rust
|
|
/// let a = [1, 2, 3, 4, 5];
|
|
/// assert!(a.iter().all(|&x| *x > 0));
|
|
/// assert!(!a.iter().all(|&x| *x > 2));
|
|
/// ```
|
|
#[inline]
|
|
fn all(&mut self, f: |A| -> bool) -> bool {
|
|
for x in *self { if !f(x) { return false; } }
|
|
true
|
|
}
|
|
|
|
/// Tests whether any element of an iterator satisfies the specified
|
|
/// predicate.
|
|
///
|
|
/// # Example
|
|
///
|
|
/// ```rust
|
|
/// let a = [1, 2, 3, 4, 5];
|
|
/// let mut it = a.iter();
|
|
/// assert!(it.any(|&x| *x == 3));
|
|
/// assert!(!it.any(|&x| *x == 3));
|
|
/// ```
|
|
#[inline]
|
|
fn any(&mut self, f: |A| -> bool) -> bool {
|
|
for x in *self { if f(x) { return true; } }
|
|
false
|
|
}
|
|
|
|
/// Return the first element satisfying the specified predicate
|
|
#[inline]
|
|
fn find(&mut self, predicate: |&A| -> bool) -> Option<A> {
|
|
for x in *self {
|
|
if predicate(&x) { return Some(x) }
|
|
}
|
|
None
|
|
}
|
|
|
|
/// Return the index of the first element satisfying the specified predicate
|
|
#[inline]
|
|
fn position(&mut self, predicate: |A| -> bool) -> Option<uint> {
|
|
let mut i = 0;
|
|
for x in *self {
|
|
if predicate(x) {
|
|
return Some(i);
|
|
}
|
|
i += 1;
|
|
}
|
|
None
|
|
}
|
|
|
|
/// Count the number of elements satisfying the specified predicate
|
|
#[inline]
|
|
fn count(&mut self, predicate: |A| -> bool) -> uint {
|
|
let mut i = 0;
|
|
for x in *self {
|
|
if predicate(x) { i += 1 }
|
|
}
|
|
i
|
|
}
|
|
|
|
/// Return the element that gives the maximum value from the
|
|
/// specified function.
|
|
///
|
|
/// # Example
|
|
///
|
|
/// ```rust
|
|
/// let xs = [-3, 0, 1, 5, -10];
|
|
/// assert_eq!(*xs.iter().max_by(|x| x.abs()).unwrap(), -10);
|
|
/// ```
|
|
#[inline]
|
|
fn max_by<B: Ord>(&mut self, f: |&A| -> B) -> Option<A> {
|
|
self.fold(None, |max: Option<(A, B)>, x| {
|
|
let x_val = f(&x);
|
|
match max {
|
|
None => Some((x, x_val)),
|
|
Some((y, y_val)) => if x_val > y_val {
|
|
Some((x, x_val))
|
|
} else {
|
|
Some((y, y_val))
|
|
}
|
|
}
|
|
}).map(|(x, _)| x)
|
|
}
|
|
|
|
/// Return the element that gives the minimum value from the
|
|
/// specified function.
|
|
///
|
|
/// # Example
|
|
///
|
|
/// ```rust
|
|
/// let xs = [-3, 0, 1, 5, -10];
|
|
/// assert_eq!(*xs.iter().min_by(|x| x.abs()).unwrap(), 0);
|
|
/// ```
|
|
#[inline]
|
|
fn min_by<B: Ord>(&mut self, f: |&A| -> B) -> Option<A> {
|
|
self.fold(None, |min: Option<(A, B)>, x| {
|
|
let x_val = f(&x);
|
|
match min {
|
|
None => Some((x, x_val)),
|
|
Some((y, y_val)) => if x_val < y_val {
|
|
Some((x, x_val))
|
|
} else {
|
|
Some((y, y_val))
|
|
}
|
|
}
|
|
}).map(|(x, _)| x)
|
|
}
|
|
}
|
|
|
|
/// A range iterator able to yield elements from both ends
|
|
pub trait DoubleEndedIterator<A>: Iterator<A> {
|
|
/// Yield an element from the end of the range, returning `None` if the range is empty.
|
|
fn next_back(&mut self) -> Option<A>;
|
|
|
|
/// Flip the direction of the iterator
|
|
///
|
|
/// The inverted iterator flips the ends on an iterator that can already
|
|
/// be iterated from the front and from the back.
|
|
///
|
|
///
|
|
/// If the iterator also implements RandomAccessIterator, the inverted
|
|
/// iterator is also random access, with the indices starting at the back
|
|
/// of the original iterator.
|
|
///
|
|
/// Note: Random access with inverted indices still only applies to the first
|
|
/// `uint::max_value` elements of the original iterator.
|
|
#[inline]
|
|
fn invert(self) -> Invert<Self> {
|
|
Invert{iter: self}
|
|
}
|
|
}
|
|
|
|
/// A double-ended iterator yielding mutable references
|
|
pub trait MutableDoubleEndedIterator {
|
|
// FIXME: #5898: should be called `reverse`
|
|
/// Use an iterator to reverse a container in-place
|
|
fn reverse_(&mut self);
|
|
}
|
|
|
|
impl<'a, A, T: DoubleEndedIterator<&'a mut A>> MutableDoubleEndedIterator for T {
|
|
// FIXME: #5898: should be called `reverse`
|
|
/// Use an iterator to reverse a container in-place
|
|
fn reverse_(&mut self) {
|
|
loop {
|
|
match (self.next(), self.next_back()) {
|
|
(Some(x), Some(y)) => util::swap(x, y),
|
|
_ => break
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
/// An object implementing random access indexing by `uint`
|
|
///
|
|
/// A `RandomAccessIterator` should be either infinite or a `DoubleEndedIterator`.
|
|
pub trait RandomAccessIterator<A>: Iterator<A> {
|
|
/// Return the number of indexable elements. At most `std::uint::max_value`
|
|
/// elements are indexable, even if the iterator represents a longer range.
|
|
fn indexable(&self) -> uint;
|
|
|
|
/// Return an element at an index
|
|
fn idx(&self, index: uint) -> Option<A>;
|
|
}
|
|
|
|
/// An iterator that knows its exact length
|
|
///
|
|
/// This trait is a helper for iterators like the vector iterator, so that
|
|
/// it can support double-ended enumeration.
|
|
///
|
|
/// `Iterator::size_hint` *must* return the exact size of the iterator.
|
|
/// Note that the size must fit in `uint`.
|
|
pub trait ExactSize<A> : DoubleEndedIterator<A> {
|
|
/// Return the index of the last element satisfying the specified predicate
|
|
///
|
|
/// If no element matches, None is returned.
|
|
#[inline]
|
|
fn rposition(&mut self, predicate: |A| -> bool) -> Option<uint> {
|
|
let (lower, upper) = self.size_hint();
|
|
assert!(upper == Some(lower));
|
|
let mut i = lower;
|
|
loop {
|
|
match self.next_back() {
|
|
None => break,
|
|
Some(x) => {
|
|
i = match i.checked_sub(&1) {
|
|
Some(x) => x,
|
|
None => fail!("rposition: incorrect ExactSize")
|
|
};
|
|
if predicate(x) {
|
|
return Some(i)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
None
|
|
}
|
|
}
|
|
|
|
// All adaptors that preserve the size of the wrapped iterator are fine
|
|
// Adaptors that may overflow in `size_hint` are not, i.e. `Chain`.
|
|
impl<A, T: ExactSize<A>> ExactSize<(uint, A)> for Enumerate<T> {}
|
|
impl<'a, A, T: ExactSize<A>> ExactSize<A> for Inspect<'a, A, T> {}
|
|
impl<A, T: ExactSize<A>> ExactSize<A> for Invert<T> {}
|
|
impl<'a, A, B, T: ExactSize<A>> ExactSize<B> for Map<'a, A, B, T> {}
|
|
impl<A, B, T: ExactSize<A>, U: ExactSize<B>> ExactSize<(A, B)> for Zip<T, U> {}
|
|
|
|
/// An double-ended iterator with the direction inverted
|
|
#[deriving(Clone)]
|
|
pub struct Invert<T> {
|
|
priv iter: T
|
|
}
|
|
|
|
impl<A, T: DoubleEndedIterator<A>> Iterator<A> for Invert<T> {
|
|
#[inline]
|
|
fn next(&mut self) -> Option<A> { self.iter.next_back() }
|
|
#[inline]
|
|
fn size_hint(&self) -> (uint, Option<uint>) { self.iter.size_hint() }
|
|
}
|
|
|
|
impl<A, T: DoubleEndedIterator<A>> DoubleEndedIterator<A> for Invert<T> {
|
|
#[inline]
|
|
fn next_back(&mut self) -> Option<A> { self.iter.next() }
|
|
}
|
|
|
|
impl<A, T: DoubleEndedIterator<A> + RandomAccessIterator<A>> RandomAccessIterator<A>
|
|
for Invert<T> {
|
|
#[inline]
|
|
fn indexable(&self) -> uint { self.iter.indexable() }
|
|
#[inline]
|
|
fn idx(&self, index: uint) -> Option<A> {
|
|
self.iter.idx(self.indexable() - index - 1)
|
|
}
|
|
}
|
|
|
|
/// A mutable reference to an iterator
|
|
pub struct ByRef<'a, T> {
|
|
priv iter: &'a mut T
|
|
}
|
|
|
|
impl<'a, A, T: Iterator<A>> Iterator<A> for ByRef<'a, T> {
|
|
#[inline]
|
|
fn next(&mut self) -> Option<A> { self.iter.next() }
|
|
// FIXME: #9629 we cannot implement &self methods like size_hint on ByRef
|
|
}
|
|
|
|
impl<'a, A, T: DoubleEndedIterator<A>> DoubleEndedIterator<A> for ByRef<'a, T> {
|
|
#[inline]
|
|
fn next_back(&mut self) -> Option<A> { self.iter.next_back() }
|
|
}
|
|
|
|
/// A trait for iterators over elements which can be added together
|
|
pub trait AdditiveIterator<A> {
|
|
/// Iterates over the entire iterator, summing up all the elements
|
|
///
|
|
/// # Example
|
|
///
|
|
/// ```rust
|
|
/// let a = [1, 2, 3, 4, 5];
|
|
/// let mut it = a.iter().map(|&x| x);
|
|
/// assert!(it.sum() == 15);
|
|
/// ```
|
|
fn sum(&mut self) -> A;
|
|
}
|
|
|
|
impl<A: Add<A, A> + Zero, T: Iterator<A>> AdditiveIterator<A> for T {
|
|
#[inline]
|
|
fn sum(&mut self) -> A {
|
|
let zero: A = Zero::zero();
|
|
self.fold(zero, |s, x| s + x)
|
|
}
|
|
}
|
|
|
|
/// A trait for iterators over elements whose elements can be multiplied
|
|
/// together.
|
|
pub trait MultiplicativeIterator<A> {
|
|
/// Iterates over the entire iterator, multiplying all the elements
|
|
///
|
|
/// # Example
|
|
///
|
|
/// ```rust
|
|
/// use std::iter::count;
|
|
///
|
|
/// fn factorial(n: uint) -> uint {
|
|
/// count(1u, 1).take_while(|&i| i <= n).product()
|
|
/// }
|
|
/// assert!(factorial(0) == 1);
|
|
/// assert!(factorial(1) == 1);
|
|
/// assert!(factorial(5) == 120);
|
|
/// ```
|
|
fn product(&mut self) -> A;
|
|
}
|
|
|
|
impl<A: Mul<A, A> + One, T: Iterator<A>> MultiplicativeIterator<A> for T {
|
|
#[inline]
|
|
fn product(&mut self) -> A {
|
|
let one: A = One::one();
|
|
self.fold(one, |p, x| p * x)
|
|
}
|
|
}
|
|
|
|
/// A trait for iterators over elements which can be compared to one another.
|
|
/// The type of each element must ascribe to the `Ord` trait.
|
|
pub trait OrdIterator<A> {
|
|
/// Consumes the entire iterator to return the maximum element.
|
|
///
|
|
/// # Example
|
|
///
|
|
/// ```rust
|
|
/// let a = [1, 2, 3, 4, 5];
|
|
/// assert!(a.iter().max().unwrap() == &5);
|
|
/// ```
|
|
fn max(&mut self) -> Option<A>;
|
|
|
|
/// Consumes the entire iterator to return the minimum element.
|
|
///
|
|
/// # Example
|
|
///
|
|
/// ```rust
|
|
/// let a = [1, 2, 3, 4, 5];
|
|
/// assert!(a.iter().min().unwrap() == &1);
|
|
/// ```
|
|
fn min(&mut self) -> Option<A>;
|
|
}
|
|
|
|
impl<A: Ord, T: Iterator<A>> OrdIterator<A> for T {
|
|
#[inline]
|
|
fn max(&mut self) -> Option<A> {
|
|
self.fold(None, |max, x| {
|
|
match max {
|
|
None => Some(x),
|
|
Some(y) => Some(cmp::max(x, y))
|
|
}
|
|
})
|
|
}
|
|
|
|
#[inline]
|
|
fn min(&mut self) -> Option<A> {
|
|
self.fold(None, |min, x| {
|
|
match min {
|
|
None => Some(x),
|
|
Some(y) => Some(cmp::min(x, y))
|
|
}
|
|
})
|
|
}
|
|
}
|
|
|
|
/// A trait for iterators that are clonable.
|
|
pub trait ClonableIterator {
|
|
/// Repeats an iterator endlessly
|
|
///
|
|
/// # Example
|
|
///
|
|
/// ```rust
|
|
/// let a = count(1,1).take(1);
|
|
/// let mut cy = a.cycle();
|
|
/// assert_eq!(cy.next(), Some(1));
|
|
/// assert_eq!(cy.next(), Some(1));
|
|
/// ```
|
|
fn cycle(self) -> Cycle<Self>;
|
|
}
|
|
|
|
impl<A, T: Clone + Iterator<A>> ClonableIterator for T {
|
|
#[inline]
|
|
fn cycle(self) -> Cycle<T> {
|
|
Cycle{orig: self.clone(), iter: self}
|
|
}
|
|
}
|
|
|
|
/// An iterator that repeats endlessly
|
|
#[deriving(Clone)]
|
|
pub struct Cycle<T> {
|
|
priv orig: T,
|
|
priv iter: T,
|
|
}
|
|
|
|
impl<A, T: Clone + Iterator<A>> Iterator<A> for Cycle<T> {
|
|
#[inline]
|
|
fn next(&mut self) -> Option<A> {
|
|
match self.iter.next() {
|
|
None => { self.iter = self.orig.clone(); self.iter.next() }
|
|
y => y
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
fn size_hint(&self) -> (uint, Option<uint>) {
|
|
// the cycle iterator is either empty or infinite
|
|
match self.orig.size_hint() {
|
|
sz @ (0, Some(0)) => sz,
|
|
(0, _) => (0, None),
|
|
_ => (uint::max_value, None)
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<A, T: Clone + RandomAccessIterator<A>> RandomAccessIterator<A> for Cycle<T> {
|
|
#[inline]
|
|
fn indexable(&self) -> uint {
|
|
if self.orig.indexable() > 0 {
|
|
uint::max_value
|
|
} else {
|
|
0
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
fn idx(&self, index: uint) -> Option<A> {
|
|
let liter = self.iter.indexable();
|
|
let lorig = self.orig.indexable();
|
|
if lorig == 0 {
|
|
None
|
|
} else if index < liter {
|
|
self.iter.idx(index)
|
|
} else {
|
|
self.orig.idx((index - liter) % lorig)
|
|
}
|
|
}
|
|
}
|
|
|
|
/// An iterator which strings two iterators together
|
|
#[deriving(Clone)]
|
|
pub struct Chain<T, U> {
|
|
priv a: T,
|
|
priv b: U,
|
|
priv flag: bool
|
|
}
|
|
|
|
impl<A, T: Iterator<A>, U: Iterator<A>> Iterator<A> for Chain<T, U> {
|
|
#[inline]
|
|
fn next(&mut self) -> Option<A> {
|
|
if self.flag {
|
|
self.b.next()
|
|
} else {
|
|
match self.a.next() {
|
|
Some(x) => return Some(x),
|
|
_ => ()
|
|
}
|
|
self.flag = true;
|
|
self.b.next()
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
fn size_hint(&self) -> (uint, Option<uint>) {
|
|
let (a_lower, a_upper) = self.a.size_hint();
|
|
let (b_lower, b_upper) = self.b.size_hint();
|
|
|
|
let lower = a_lower.saturating_add(b_lower);
|
|
|
|
let upper = match (a_upper, b_upper) {
|
|
(Some(x), Some(y)) => x.checked_add(&y),
|
|
_ => None
|
|
};
|
|
|
|
(lower, upper)
|
|
}
|
|
}
|
|
|
|
impl<A, T: DoubleEndedIterator<A>, U: DoubleEndedIterator<A>> DoubleEndedIterator<A>
|
|
for Chain<T, U> {
|
|
#[inline]
|
|
fn next_back(&mut self) -> Option<A> {
|
|
match self.b.next_back() {
|
|
Some(x) => Some(x),
|
|
None => self.a.next_back()
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<A, T: RandomAccessIterator<A>, U: RandomAccessIterator<A>> RandomAccessIterator<A>
|
|
for Chain<T, U> {
|
|
#[inline]
|
|
fn indexable(&self) -> uint {
|
|
let (a, b) = (self.a.indexable(), self.b.indexable());
|
|
a.saturating_add(b)
|
|
}
|
|
|
|
#[inline]
|
|
fn idx(&self, index: uint) -> Option<A> {
|
|
let len = self.a.indexable();
|
|
if index < len {
|
|
self.a.idx(index)
|
|
} else {
|
|
self.b.idx(index - len)
|
|
}
|
|
}
|
|
}
|
|
|
|
/// An iterator which iterates two other iterators simultaneously
|
|
#[deriving(Clone)]
|
|
pub struct Zip<T, U> {
|
|
priv a: T,
|
|
priv b: U
|
|
}
|
|
|
|
impl<A, B, T: Iterator<A>, U: Iterator<B>> Iterator<(A, B)> for Zip<T, U> {
|
|
#[inline]
|
|
fn next(&mut self) -> Option<(A, B)> {
|
|
match self.a.next() {
|
|
None => None,
|
|
Some(x) => match self.b.next() {
|
|
None => None,
|
|
Some(y) => Some((x, y))
|
|
}
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
fn size_hint(&self) -> (uint, Option<uint>) {
|
|
let (a_lower, a_upper) = self.a.size_hint();
|
|
let (b_lower, b_upper) = self.b.size_hint();
|
|
|
|
let lower = cmp::min(a_lower, b_lower);
|
|
|
|
let upper = match (a_upper, b_upper) {
|
|
(Some(x), Some(y)) => Some(cmp::min(x,y)),
|
|
(Some(x), None) => Some(x),
|
|
(None, Some(y)) => Some(y),
|
|
(None, None) => None
|
|
};
|
|
|
|
(lower, upper)
|
|
}
|
|
}
|
|
|
|
impl<A, B, T: ExactSize<A>, U: ExactSize<B>> DoubleEndedIterator<(A, B)>
|
|
for Zip<T, U> {
|
|
#[inline]
|
|
fn next_back(&mut self) -> Option<(A, B)> {
|
|
let (a_sz, a_upper) = self.a.size_hint();
|
|
let (b_sz, b_upper) = self.b.size_hint();
|
|
assert!(a_upper == Some(a_sz));
|
|
assert!(b_upper == Some(b_sz));
|
|
if a_sz < b_sz {
|
|
for _ in range(0, b_sz - a_sz) { self.b.next_back(); }
|
|
} else if a_sz > b_sz {
|
|
for _ in range(0, a_sz - b_sz) { self.a.next_back(); }
|
|
}
|
|
let (a_sz, _) = self.a.size_hint();
|
|
let (b_sz, _) = self.b.size_hint();
|
|
assert!(a_sz == b_sz);
|
|
match (self.a.next_back(), self.b.next_back()) {
|
|
(Some(x), Some(y)) => Some((x, y)),
|
|
_ => None
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<A, B, T: RandomAccessIterator<A>, U: RandomAccessIterator<B>>
|
|
RandomAccessIterator<(A, B)> for Zip<T, U> {
|
|
#[inline]
|
|
fn indexable(&self) -> uint {
|
|
cmp::min(self.a.indexable(), self.b.indexable())
|
|
}
|
|
|
|
#[inline]
|
|
fn idx(&self, index: uint) -> Option<(A, B)> {
|
|
match self.a.idx(index) {
|
|
None => None,
|
|
Some(x) => match self.b.idx(index) {
|
|
None => None,
|
|
Some(y) => Some((x, y))
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/// An iterator which maps the values of `iter` with `f`
|
|
pub struct Map<'a, A, B, T> {
|
|
priv iter: T,
|
|
priv f: 'a |A| -> B
|
|
}
|
|
|
|
impl<'a, A, B, T> Map<'a, A, B, T> {
|
|
#[inline]
|
|
fn do_map(&self, elt: Option<A>) -> Option<B> {
|
|
match elt {
|
|
Some(a) => Some((self.f)(a)),
|
|
_ => None
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<'a, A, B, T: Iterator<A>> Iterator<B> for Map<'a, A, B, T> {
|
|
#[inline]
|
|
fn next(&mut self) -> Option<B> {
|
|
let next = self.iter.next();
|
|
self.do_map(next)
|
|
}
|
|
|
|
#[inline]
|
|
fn size_hint(&self) -> (uint, Option<uint>) {
|
|
self.iter.size_hint()
|
|
}
|
|
}
|
|
|
|
impl<'a, A, B, T: DoubleEndedIterator<A>> DoubleEndedIterator<B> for Map<'a, A, B, T> {
|
|
#[inline]
|
|
fn next_back(&mut self) -> Option<B> {
|
|
let next = self.iter.next_back();
|
|
self.do_map(next)
|
|
}
|
|
}
|
|
|
|
impl<'a, A, B, T: RandomAccessIterator<A>> RandomAccessIterator<B> for Map<'a, A, B, T> {
|
|
#[inline]
|
|
fn indexable(&self) -> uint {
|
|
self.iter.indexable()
|
|
}
|
|
|
|
#[inline]
|
|
fn idx(&self, index: uint) -> Option<B> {
|
|
self.do_map(self.iter.idx(index))
|
|
}
|
|
}
|
|
|
|
/// An iterator which filters the elements of `iter` with `predicate`
|
|
pub struct Filter<'a, A, T> {
|
|
priv iter: T,
|
|
priv predicate: 'a |&A| -> bool
|
|
}
|
|
|
|
impl<'a, A, T: Iterator<A>> Iterator<A> for Filter<'a, A, T> {
|
|
#[inline]
|
|
fn next(&mut self) -> Option<A> {
|
|
for x in self.iter {
|
|
if (self.predicate)(&x) {
|
|
return Some(x);
|
|
} else {
|
|
continue
|
|
}
|
|
}
|
|
None
|
|
}
|
|
|
|
#[inline]
|
|
fn size_hint(&self) -> (uint, Option<uint>) {
|
|
let (_, upper) = self.iter.size_hint();
|
|
(0, upper) // can't know a lower bound, due to the predicate
|
|
}
|
|
}
|
|
|
|
impl<'a, A, T: DoubleEndedIterator<A>> DoubleEndedIterator<A> for Filter<'a, A, T> {
|
|
#[inline]
|
|
fn next_back(&mut self) -> Option<A> {
|
|
loop {
|
|
match self.iter.next_back() {
|
|
None => return None,
|
|
Some(x) => {
|
|
if (self.predicate)(&x) {
|
|
return Some(x);
|
|
} else {
|
|
continue
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/// An iterator which uses `f` to both filter and map elements from `iter`
|
|
pub struct FilterMap<'a, A, B, T> {
|
|
priv iter: T,
|
|
priv f: 'a |A| -> Option<B>
|
|
}
|
|
|
|
impl<'a, A, B, T: Iterator<A>> Iterator<B> for FilterMap<'a, A, B, T> {
|
|
#[inline]
|
|
fn next(&mut self) -> Option<B> {
|
|
for x in self.iter {
|
|
match (self.f)(x) {
|
|
Some(y) => return Some(y),
|
|
None => ()
|
|
}
|
|
}
|
|
None
|
|
}
|
|
|
|
#[inline]
|
|
fn size_hint(&self) -> (uint, Option<uint>) {
|
|
let (_, upper) = self.iter.size_hint();
|
|
(0, upper) // can't know a lower bound, due to the predicate
|
|
}
|
|
}
|
|
|
|
impl<'a, A, B, T: DoubleEndedIterator<A>> DoubleEndedIterator<B>
|
|
for FilterMap<'a, A, B, T> {
|
|
#[inline]
|
|
fn next_back(&mut self) -> Option<B> {
|
|
loop {
|
|
match self.iter.next_back() {
|
|
None => return None,
|
|
Some(x) => {
|
|
match (self.f)(x) {
|
|
Some(y) => return Some(y),
|
|
None => ()
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/// An iterator which yields the current count and the element during iteration
|
|
#[deriving(Clone)]
|
|
pub struct Enumerate<T> {
|
|
priv iter: T,
|
|
priv count: uint
|
|
}
|
|
|
|
impl<A, T: Iterator<A>> Iterator<(uint, A)> for Enumerate<T> {
|
|
#[inline]
|
|
fn next(&mut self) -> Option<(uint, A)> {
|
|
match self.iter.next() {
|
|
Some(a) => {
|
|
let ret = Some((self.count, a));
|
|
self.count += 1;
|
|
ret
|
|
}
|
|
_ => None
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
fn size_hint(&self) -> (uint, Option<uint>) {
|
|
self.iter.size_hint()
|
|
}
|
|
}
|
|
|
|
impl<A, T: ExactSize<A>> DoubleEndedIterator<(uint, A)> for Enumerate<T> {
|
|
#[inline]
|
|
fn next_back(&mut self) -> Option<(uint, A)> {
|
|
match self.iter.next_back() {
|
|
Some(a) => {
|
|
let (lower, upper) = self.iter.size_hint();
|
|
assert!(upper == Some(lower));
|
|
Some((self.count + lower, a))
|
|
}
|
|
_ => None
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<A, T: RandomAccessIterator<A>> RandomAccessIterator<(uint, A)> for Enumerate<T> {
|
|
#[inline]
|
|
fn indexable(&self) -> uint {
|
|
self.iter.indexable()
|
|
}
|
|
|
|
#[inline]
|
|
fn idx(&self, index: uint) -> Option<(uint, A)> {
|
|
match self.iter.idx(index) {
|
|
Some(a) => Some((self.count + index, a)),
|
|
_ => None,
|
|
}
|
|
}
|
|
}
|
|
|
|
/// An iterator with a `peek()` that returns an optional reference to the next element.
|
|
pub struct Peekable<A, T> {
|
|
priv iter: T,
|
|
priv peeked: Option<A>,
|
|
}
|
|
|
|
impl<A, T: Iterator<A>> Iterator<A> for Peekable<A, T> {
|
|
#[inline]
|
|
fn next(&mut self) -> Option<A> {
|
|
if self.peeked.is_some() { self.peeked.take() }
|
|
else { self.iter.next() }
|
|
}
|
|
|
|
#[inline]
|
|
fn size_hint(&self) -> (uint, Option<uint>) {
|
|
let (lo, hi) = self.iter.size_hint();
|
|
if self.peeked.is_some() {
|
|
let lo = lo.saturating_add(1);
|
|
let hi = match hi {
|
|
Some(x) => x.checked_add(&1),
|
|
None => None
|
|
};
|
|
(lo, hi)
|
|
} else {
|
|
(lo, hi)
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<'a, A, T: Iterator<A>> Peekable<A, T> {
|
|
/// Return a reference to the next element of the iterator with out advancing it,
|
|
/// or None if the iterator is exhausted.
|
|
#[inline]
|
|
pub fn peek(&'a mut self) -> Option<&'a A> {
|
|
if self.peeked.is_none() {
|
|
self.peeked = self.iter.next();
|
|
}
|
|
match self.peeked {
|
|
Some(ref value) => Some(value),
|
|
None => None,
|
|
}
|
|
}
|
|
}
|
|
|
|
/// An iterator which rejects elements while `predicate` is true
|
|
pub struct SkipWhile<'a, A, T> {
|
|
priv iter: T,
|
|
priv flag: bool,
|
|
priv predicate: 'a |&A| -> bool
|
|
}
|
|
|
|
impl<'a, A, T: Iterator<A>> Iterator<A> for SkipWhile<'a, A, T> {
|
|
#[inline]
|
|
fn next(&mut self) -> Option<A> {
|
|
let mut next = self.iter.next();
|
|
if self.flag {
|
|
next
|
|
} else {
|
|
loop {
|
|
match next {
|
|
Some(x) => {
|
|
if (self.predicate)(&x) {
|
|
next = self.iter.next();
|
|
continue
|
|
} else {
|
|
self.flag = true;
|
|
return Some(x)
|
|
}
|
|
}
|
|
None => return None
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
fn size_hint(&self) -> (uint, Option<uint>) {
|
|
let (_, upper) = self.iter.size_hint();
|
|
(0, upper) // can't know a lower bound, due to the predicate
|
|
}
|
|
}
|
|
|
|
/// An iterator which only accepts elements while `predicate` is true
|
|
pub struct TakeWhile<'a, A, T> {
|
|
priv iter: T,
|
|
priv flag: bool,
|
|
priv predicate: 'a |&A| -> bool
|
|
}
|
|
|
|
impl<'a, A, T: Iterator<A>> Iterator<A> for TakeWhile<'a, A, T> {
|
|
#[inline]
|
|
fn next(&mut self) -> Option<A> {
|
|
if self.flag {
|
|
None
|
|
} else {
|
|
match self.iter.next() {
|
|
Some(x) => {
|
|
if (self.predicate)(&x) {
|
|
Some(x)
|
|
} else {
|
|
self.flag = true;
|
|
None
|
|
}
|
|
}
|
|
None => None
|
|
}
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
fn size_hint(&self) -> (uint, Option<uint>) {
|
|
let (_, upper) = self.iter.size_hint();
|
|
(0, upper) // can't know a lower bound, due to the predicate
|
|
}
|
|
}
|
|
|
|
/// An iterator which skips over `n` elements of `iter`.
|
|
#[deriving(Clone)]
|
|
pub struct Skip<T> {
|
|
priv iter: T,
|
|
priv n: uint
|
|
}
|
|
|
|
impl<A, T: Iterator<A>> Iterator<A> for Skip<T> {
|
|
#[inline]
|
|
fn next(&mut self) -> Option<A> {
|
|
let mut next = self.iter.next();
|
|
if self.n == 0 {
|
|
next
|
|
} else {
|
|
let mut n = self.n;
|
|
while n > 0 {
|
|
n -= 1;
|
|
match next {
|
|
Some(_) => {
|
|
next = self.iter.next();
|
|
continue
|
|
}
|
|
None => {
|
|
self.n = 0;
|
|
return None
|
|
}
|
|
}
|
|
}
|
|
self.n = 0;
|
|
next
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
fn size_hint(&self) -> (uint, Option<uint>) {
|
|
let (lower, upper) = self.iter.size_hint();
|
|
|
|
let lower = lower.saturating_sub(self.n);
|
|
|
|
let upper = match upper {
|
|
Some(x) => Some(x.saturating_sub(self.n)),
|
|
None => None
|
|
};
|
|
|
|
(lower, upper)
|
|
}
|
|
}
|
|
|
|
impl<A, T: RandomAccessIterator<A>> RandomAccessIterator<A> for Skip<T> {
|
|
#[inline]
|
|
fn indexable(&self) -> uint {
|
|
self.iter.indexable().saturating_sub(self.n)
|
|
}
|
|
|
|
#[inline]
|
|
fn idx(&self, index: uint) -> Option<A> {
|
|
if index >= self.indexable() {
|
|
None
|
|
} else {
|
|
self.iter.idx(index + self.n)
|
|
}
|
|
}
|
|
}
|
|
|
|
/// An iterator which only iterates over the first `n` iterations of `iter`.
|
|
#[deriving(Clone)]
|
|
pub struct Take<T> {
|
|
priv iter: T,
|
|
priv n: uint
|
|
}
|
|
|
|
impl<A, T: Iterator<A>> Iterator<A> for Take<T> {
|
|
#[inline]
|
|
fn next(&mut self) -> Option<A> {
|
|
if self.n != 0 {
|
|
self.n -= 1;
|
|
self.iter.next()
|
|
} else {
|
|
None
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
fn size_hint(&self) -> (uint, Option<uint>) {
|
|
let (lower, upper) = self.iter.size_hint();
|
|
|
|
let lower = cmp::min(lower, self.n);
|
|
|
|
let upper = match upper {
|
|
Some(x) if x < self.n => Some(x),
|
|
_ => Some(self.n)
|
|
};
|
|
|
|
(lower, upper)
|
|
}
|
|
}
|
|
|
|
impl<A, T: RandomAccessIterator<A>> RandomAccessIterator<A> for Take<T> {
|
|
#[inline]
|
|
fn indexable(&self) -> uint {
|
|
cmp::min(self.iter.indexable(), self.n)
|
|
}
|
|
|
|
#[inline]
|
|
fn idx(&self, index: uint) -> Option<A> {
|
|
if index >= self.n {
|
|
None
|
|
} else {
|
|
self.iter.idx(index)
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
/// An iterator to maintain state while iterating another iterator
|
|
pub struct Scan<'a, A, B, T, St> {
|
|
priv iter: T,
|
|
priv f: 'a |&mut St, A| -> Option<B>,
|
|
|
|
/// The current internal state to be passed to the closure next.
|
|
state: St
|
|
}
|
|
|
|
impl<'a, A, B, T: Iterator<A>, St> Iterator<B> for Scan<'a, A, B, T, St> {
|
|
#[inline]
|
|
fn next(&mut self) -> Option<B> {
|
|
self.iter.next().and_then(|a| (self.f)(&mut self.state, a))
|
|
}
|
|
|
|
#[inline]
|
|
fn size_hint(&self) -> (uint, Option<uint>) {
|
|
let (_, upper) = self.iter.size_hint();
|
|
(0, upper) // can't know a lower bound, due to the scan function
|
|
}
|
|
}
|
|
|
|
/// An iterator that maps each element to an iterator,
|
|
/// and yields the elements of the produced iterators
|
|
///
|
|
pub struct FlatMap<'a, A, T, U> {
|
|
priv iter: T,
|
|
priv f: 'a |A| -> U,
|
|
priv frontiter: Option<U>,
|
|
priv backiter: Option<U>,
|
|
}
|
|
|
|
impl<'a, A, T: Iterator<A>, B, U: Iterator<B>> Iterator<B> for FlatMap<'a, A, T, U> {
|
|
#[inline]
|
|
fn next(&mut self) -> Option<B> {
|
|
loop {
|
|
for inner in self.frontiter.mut_iter() {
|
|
for x in *inner {
|
|
return Some(x)
|
|
}
|
|
}
|
|
match self.iter.next().map(|x| (self.f)(x)) {
|
|
None => return self.backiter.as_mut().and_then(|it| it.next()),
|
|
next => self.frontiter = next,
|
|
}
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
fn size_hint(&self) -> (uint, Option<uint>) {
|
|
let (flo, fhi) = self.frontiter.as_ref().map_default((0, Some(0)), |it| it.size_hint());
|
|
let (blo, bhi) = self.backiter.as_ref().map_default((0, Some(0)), |it| it.size_hint());
|
|
let lo = flo.saturating_add(blo);
|
|
match (self.iter.size_hint(), fhi, bhi) {
|
|
((0, Some(0)), Some(a), Some(b)) => (lo, a.checked_add(&b)),
|
|
_ => (lo, None)
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<'a,
|
|
A, T: DoubleEndedIterator<A>,
|
|
B, U: DoubleEndedIterator<B>> DoubleEndedIterator<B>
|
|
for FlatMap<'a, A, T, U> {
|
|
#[inline]
|
|
fn next_back(&mut self) -> Option<B> {
|
|
loop {
|
|
for inner in self.backiter.mut_iter() {
|
|
match inner.next_back() {
|
|
None => (),
|
|
y => return y
|
|
}
|
|
}
|
|
match self.iter.next_back().map(|x| (self.f)(x)) {
|
|
None => return self.frontiter.as_mut().and_then(|it| it.next_back()),
|
|
next => self.backiter = next,
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/// An iterator that yields `None` forever after the underlying iterator
|
|
/// yields `None` once.
|
|
#[deriving(Clone, DeepClone)]
|
|
pub struct Fuse<T> {
|
|
priv iter: T,
|
|
priv done: bool
|
|
}
|
|
|
|
impl<A, T: Iterator<A>> Iterator<A> for Fuse<T> {
|
|
#[inline]
|
|
fn next(&mut self) -> Option<A> {
|
|
if self.done {
|
|
None
|
|
} else {
|
|
match self.iter.next() {
|
|
None => {
|
|
self.done = true;
|
|
None
|
|
}
|
|
x => x
|
|
}
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
fn size_hint(&self) -> (uint, Option<uint>) {
|
|
if self.done {
|
|
(0, Some(0))
|
|
} else {
|
|
self.iter.size_hint()
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<A, T: DoubleEndedIterator<A>> DoubleEndedIterator<A> for Fuse<T> {
|
|
#[inline]
|
|
fn next_back(&mut self) -> Option<A> {
|
|
if self.done {
|
|
None
|
|
} else {
|
|
match self.iter.next_back() {
|
|
None => {
|
|
self.done = true;
|
|
None
|
|
}
|
|
x => x
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// Allow RandomAccessIterators to be fused without affecting random-access behavior
|
|
impl<A, T: RandomAccessIterator<A>> RandomAccessIterator<A> for Fuse<T> {
|
|
#[inline]
|
|
fn indexable(&self) -> uint {
|
|
self.iter.indexable()
|
|
}
|
|
|
|
#[inline]
|
|
fn idx(&self, index: uint) -> Option<A> {
|
|
self.iter.idx(index)
|
|
}
|
|
}
|
|
|
|
impl<T> Fuse<T> {
|
|
/// Resets the fuse such that the next call to .next() or .next_back() will
|
|
/// call the underlying iterator again even if it prevously returned None.
|
|
#[inline]
|
|
pub fn reset_fuse(&mut self) {
|
|
self.done = false
|
|
}
|
|
}
|
|
|
|
/// An iterator that calls a function with a reference to each
|
|
/// element before yielding it.
|
|
pub struct Inspect<'a, A, T> {
|
|
priv iter: T,
|
|
priv f: 'a |&A|
|
|
}
|
|
|
|
impl<'a, A, T> Inspect<'a, A, T> {
|
|
#[inline]
|
|
fn do_inspect(&self, elt: Option<A>) -> Option<A> {
|
|
match elt {
|
|
Some(ref a) => (self.f)(a),
|
|
None => ()
|
|
}
|
|
|
|
elt
|
|
}
|
|
}
|
|
|
|
impl<'a, A, T: Iterator<A>> Iterator<A> for Inspect<'a, A, T> {
|
|
#[inline]
|
|
fn next(&mut self) -> Option<A> {
|
|
let next = self.iter.next();
|
|
self.do_inspect(next)
|
|
}
|
|
|
|
#[inline]
|
|
fn size_hint(&self) -> (uint, Option<uint>) {
|
|
self.iter.size_hint()
|
|
}
|
|
}
|
|
|
|
impl<'a, A, T: DoubleEndedIterator<A>> DoubleEndedIterator<A>
|
|
for Inspect<'a, A, T> {
|
|
#[inline]
|
|
fn next_back(&mut self) -> Option<A> {
|
|
let next = self.iter.next_back();
|
|
self.do_inspect(next)
|
|
}
|
|
}
|
|
|
|
impl<'a, A, T: RandomAccessIterator<A>> RandomAccessIterator<A>
|
|
for Inspect<'a, A, T> {
|
|
#[inline]
|
|
fn indexable(&self) -> uint {
|
|
self.iter.indexable()
|
|
}
|
|
|
|
#[inline]
|
|
fn idx(&self, index: uint) -> Option<A> {
|
|
self.do_inspect(self.iter.idx(index))
|
|
}
|
|
}
|
|
|
|
/// An iterator which just modifies the contained state throughout iteration.
|
|
pub struct Unfold<'a, A, St> {
|
|
priv f: 'a |&mut St| -> Option<A>,
|
|
/// Internal state that will be yielded on the next iteration
|
|
state: St
|
|
}
|
|
|
|
impl<'a, A, St> Unfold<'a, A, St> {
|
|
/// Creates a new iterator with the specified closure as the "iterator
|
|
/// function" and an initial state to eventually pass to the iterator
|
|
#[inline]
|
|
pub fn new<'a>(initial_state: St, f: 'a |&mut St| -> Option<A>)
|
|
-> Unfold<'a, A, St> {
|
|
Unfold {
|
|
f: f,
|
|
state: initial_state
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<'a, A, St> Iterator<A> for Unfold<'a, A, St> {
|
|
#[inline]
|
|
fn next(&mut self) -> Option<A> {
|
|
(self.f)(&mut self.state)
|
|
}
|
|
|
|
#[inline]
|
|
fn size_hint(&self) -> (uint, Option<uint>) {
|
|
// no possible known bounds at this point
|
|
(0, None)
|
|
}
|
|
}
|
|
|
|
/// An infinite iterator starting at `start` and advancing by `step` with each
|
|
/// iteration
|
|
#[deriving(Clone)]
|
|
pub struct Counter<A> {
|
|
/// The current state the counter is at (next value to be yielded)
|
|
priv state: A,
|
|
/// The amount that this iterator is stepping by
|
|
priv step: A
|
|
}
|
|
|
|
/// Creates a new counter with the specified start/step
|
|
#[inline]
|
|
pub fn count<A>(start: A, step: A) -> Counter<A> {
|
|
Counter{state: start, step: step}
|
|
}
|
|
|
|
impl<A: Add<A, A> + Clone> Iterator<A> for Counter<A> {
|
|
#[inline]
|
|
fn next(&mut self) -> Option<A> {
|
|
let result = self.state.clone();
|
|
self.state = self.state + self.step;
|
|
Some(result)
|
|
}
|
|
|
|
#[inline]
|
|
fn size_hint(&self) -> (uint, Option<uint>) {
|
|
(uint::max_value, None) // Too bad we can't specify an infinite lower bound
|
|
}
|
|
}
|
|
|
|
/// An iterator over the range [start, stop)
|
|
#[deriving(Clone, DeepClone)]
|
|
pub struct Range<A> {
|
|
priv state: A,
|
|
priv stop: A,
|
|
priv one: A
|
|
}
|
|
|
|
/// Return an iterator over the range [start, stop)
|
|
#[inline]
|
|
pub fn range<A: Add<A, A> + Ord + Clone + One>(start: A, stop: A) -> Range<A> {
|
|
Range{state: start, stop: stop, one: One::one()}
|
|
}
|
|
|
|
// FIXME: #10414: Unfortunate type bound
|
|
impl<A: Add<A, A> + Ord + Clone + ToPrimitive> Iterator<A> for Range<A> {
|
|
#[inline]
|
|
fn next(&mut self) -> Option<A> {
|
|
if self.state < self.stop {
|
|
let result = self.state.clone();
|
|
self.state = self.state + self.one;
|
|
Some(result)
|
|
} else {
|
|
None
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
fn size_hint(&self) -> (uint, Option<uint>) {
|
|
// This first checks if the elements are representable as i64. If they aren't, try u64 (to
|
|
// handle cases like range(huge, huger)). We don't use uint/int because the difference of
|
|
// the i64/u64 might lie within their range.
|
|
let bound = match self.state.to_i64() {
|
|
Some(a) => {
|
|
let sz = self.stop.to_i64().map(|b| b.checked_sub(&a));
|
|
match sz {
|
|
Some(Some(bound)) => bound.to_uint(),
|
|
_ => None,
|
|
}
|
|
},
|
|
None => match self.state.to_u64() {
|
|
Some(a) => {
|
|
let sz = self.stop.to_u64().map(|b| b.checked_sub(&a));
|
|
match sz {
|
|
Some(Some(bound)) => bound.to_uint(),
|
|
_ => None
|
|
}
|
|
},
|
|
None => None
|
|
}
|
|
};
|
|
|
|
match bound {
|
|
Some(b) => (b, Some(b)),
|
|
// Standard fallback for unbounded/unrepresentable bounds
|
|
None => (0, None)
|
|
}
|
|
}
|
|
}
|
|
|
|
/// `Integer` is required to ensure the range will be the same regardless of
|
|
/// the direction it is consumed.
|
|
impl<A: Integer + Ord + Clone + ToPrimitive> DoubleEndedIterator<A> for Range<A> {
|
|
#[inline]
|
|
fn next_back(&mut self) -> Option<A> {
|
|
if self.stop > self.state {
|
|
self.stop = self.stop - self.one;
|
|
Some(self.stop.clone())
|
|
} else {
|
|
None
|
|
}
|
|
}
|
|
}
|
|
|
|
/// An iterator over the range [start, stop]
|
|
#[deriving(Clone, DeepClone)]
|
|
pub struct RangeInclusive<A> {
|
|
priv range: Range<A>,
|
|
priv done: bool
|
|
}
|
|
|
|
/// Return an iterator over the range [start, stop]
|
|
#[inline]
|
|
pub fn range_inclusive<A: Add<A, A> + Ord + Clone + One + ToPrimitive>(start: A, stop: A)
|
|
-> RangeInclusive<A> {
|
|
RangeInclusive{range: range(start, stop), done: false}
|
|
}
|
|
|
|
impl<A: Add<A, A> + Eq + Ord + Clone + ToPrimitive> Iterator<A> for RangeInclusive<A> {
|
|
#[inline]
|
|
fn next(&mut self) -> Option<A> {
|
|
match self.range.next() {
|
|
Some(x) => Some(x),
|
|
None => {
|
|
if !self.done && self.range.state == self.range.stop {
|
|
self.done = true;
|
|
Some(self.range.stop.clone())
|
|
} else {
|
|
None
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
fn size_hint(&self) -> (uint, Option<uint>) {
|
|
let (lo, hi) = self.range.size_hint();
|
|
if self.done {
|
|
(lo, hi)
|
|
} else {
|
|
let lo = lo.saturating_add(1);
|
|
let hi = match hi {
|
|
Some(x) => x.checked_add(&1),
|
|
None => None
|
|
};
|
|
(lo, hi)
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<A: Sub<A, A> + Integer + Ord + Clone + ToPrimitive> DoubleEndedIterator<A>
|
|
for RangeInclusive<A> {
|
|
#[inline]
|
|
fn next_back(&mut self) -> Option<A> {
|
|
if self.range.stop > self.range.state {
|
|
let result = self.range.stop.clone();
|
|
self.range.stop = self.range.stop - self.range.one;
|
|
Some(result)
|
|
} else if !self.done && self.range.state == self.range.stop {
|
|
self.done = true;
|
|
Some(self.range.stop.clone())
|
|
} else {
|
|
None
|
|
}
|
|
}
|
|
}
|
|
|
|
/// An iterator over the range [start, stop) by `step`. It handles overflow by stopping.
|
|
#[deriving(Clone, DeepClone)]
|
|
pub struct RangeStep<A> {
|
|
priv state: A,
|
|
priv stop: A,
|
|
priv step: A,
|
|
priv rev: bool
|
|
}
|
|
|
|
/// Return an iterator over the range [start, stop) by `step`. It handles overflow by stopping.
|
|
#[inline]
|
|
pub fn range_step<A: CheckedAdd + Ord + Clone + Zero>(start: A, stop: A, step: A) -> RangeStep<A> {
|
|
let rev = step < Zero::zero();
|
|
RangeStep{state: start, stop: stop, step: step, rev: rev}
|
|
}
|
|
|
|
impl<A: CheckedAdd + Ord + Clone> Iterator<A> for RangeStep<A> {
|
|
#[inline]
|
|
fn next(&mut self) -> Option<A> {
|
|
if (self.rev && self.state > self.stop) || (!self.rev && self.state < self.stop) {
|
|
let result = self.state.clone();
|
|
match self.state.checked_add(&self.step) {
|
|
Some(x) => self.state = x,
|
|
None => self.state = self.stop.clone()
|
|
}
|
|
Some(result)
|
|
} else {
|
|
None
|
|
}
|
|
}
|
|
}
|
|
|
|
/// An iterator over the range [start, stop] by `step`. It handles overflow by stopping.
|
|
#[deriving(Clone, DeepClone)]
|
|
pub struct RangeStepInclusive<A> {
|
|
priv state: A,
|
|
priv stop: A,
|
|
priv step: A,
|
|
priv rev: bool,
|
|
priv done: bool
|
|
}
|
|
|
|
/// Return an iterator over the range [start, stop] by `step`. It handles overflow by stopping.
|
|
#[inline]
|
|
pub fn range_step_inclusive<A: CheckedAdd + Ord + Clone + Zero>(start: A, stop: A,
|
|
step: A) -> RangeStepInclusive<A> {
|
|
let rev = step < Zero::zero();
|
|
RangeStepInclusive{state: start, stop: stop, step: step, rev: rev, done: false}
|
|
}
|
|
|
|
impl<A: CheckedAdd + Ord + Clone + Eq> Iterator<A> for RangeStepInclusive<A> {
|
|
#[inline]
|
|
fn next(&mut self) -> Option<A> {
|
|
if !self.done && ((self.rev && self.state >= self.stop) ||
|
|
(!self.rev && self.state <= self.stop)) {
|
|
let result = self.state.clone();
|
|
match self.state.checked_add(&self.step) {
|
|
Some(x) => self.state = x,
|
|
None => self.done = true
|
|
}
|
|
Some(result)
|
|
} else {
|
|
None
|
|
}
|
|
}
|
|
}
|
|
|
|
/// An iterator that repeats an element endlessly
|
|
#[deriving(Clone, DeepClone)]
|
|
pub struct Repeat<A> {
|
|
priv element: A
|
|
}
|
|
|
|
impl<A: Clone> Repeat<A> {
|
|
/// Create a new `Repeat` that endlessly repeats the element `elt`.
|
|
#[inline]
|
|
pub fn new(elt: A) -> Repeat<A> {
|
|
Repeat{element: elt}
|
|
}
|
|
}
|
|
|
|
impl<A: Clone> Iterator<A> for Repeat<A> {
|
|
#[inline]
|
|
fn next(&mut self) -> Option<A> { self.idx(0) }
|
|
#[inline]
|
|
fn size_hint(&self) -> (uint, Option<uint>) { (uint::max_value, None) }
|
|
}
|
|
|
|
impl<A: Clone> DoubleEndedIterator<A> for Repeat<A> {
|
|
#[inline]
|
|
fn next_back(&mut self) -> Option<A> { self.idx(0) }
|
|
}
|
|
|
|
impl<A: Clone> RandomAccessIterator<A> for Repeat<A> {
|
|
#[inline]
|
|
fn indexable(&self) -> uint { uint::max_value }
|
|
#[inline]
|
|
fn idx(&self, _: uint) -> Option<A> { Some(self.element.clone()) }
|
|
}
|
|
|
|
/// Functions for lexicographical ordering of sequences.
|
|
///
|
|
/// Lexicographical ordering through `<`, `<=`, `>=`, `>` requires
|
|
/// that the elements implement both `Eq` and `Ord`.
|
|
///
|
|
/// If two sequences are equal up until the point where one ends,
|
|
/// the shorter sequence compares less.
|
|
pub mod order {
|
|
use cmp;
|
|
use cmp::{TotalEq, TotalOrd, Ord, Eq};
|
|
use option::{Some, None};
|
|
use super::Iterator;
|
|
|
|
/// Compare `a` and `b` for equality using `TotalOrd`
|
|
pub fn equals<A: TotalEq, T: Iterator<A>>(mut a: T, mut b: T) -> bool {
|
|
loop {
|
|
match (a.next(), b.next()) {
|
|
(None, None) => return true,
|
|
(None, _) | (_, None) => return false,
|
|
(Some(x), Some(y)) => if !x.equals(&y) { return false },
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Order `a` and `b` lexicographically using `TotalOrd`
|
|
pub fn cmp<A: TotalOrd, T: Iterator<A>>(mut a: T, mut b: T) -> cmp::Ordering {
|
|
loop {
|
|
match (a.next(), b.next()) {
|
|
(None, None) => return cmp::Equal,
|
|
(None, _ ) => return cmp::Less,
|
|
(_ , None) => return cmp::Greater,
|
|
(Some(x), Some(y)) => match x.cmp(&y) {
|
|
cmp::Equal => (),
|
|
non_eq => return non_eq,
|
|
},
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Compare `a` and `b` for equality (Using partial equality, `Eq`)
|
|
pub fn eq<A: Eq, T: Iterator<A>>(mut a: T, mut b: T) -> bool {
|
|
loop {
|
|
match (a.next(), b.next()) {
|
|
(None, None) => return true,
|
|
(None, _) | (_, None) => return false,
|
|
(Some(x), Some(y)) => if !x.eq(&y) { return false },
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Compare `a` and `b` for nonequality (Using partial equality, `Eq`)
|
|
pub fn ne<A: Eq, T: Iterator<A>>(mut a: T, mut b: T) -> bool {
|
|
loop {
|
|
match (a.next(), b.next()) {
|
|
(None, None) => return false,
|
|
(None, _) | (_, None) => return true,
|
|
(Some(x), Some(y)) => if x.ne(&y) { return true },
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Return `a` < `b` lexicographically (Using partial order, `Ord`)
|
|
pub fn lt<A: Eq + Ord, T: Iterator<A>>(mut a: T, mut b: T) -> bool {
|
|
loop {
|
|
match (a.next(), b.next()) {
|
|
(None, None) => return false,
|
|
(None, _ ) => return true,
|
|
(_ , None) => return false,
|
|
(Some(x), Some(y)) => if x.ne(&y) { return x.lt(&y) },
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Return `a` <= `b` lexicographically (Using partial order, `Ord`)
|
|
pub fn le<A: Eq + Ord, T: Iterator<A>>(mut a: T, mut b: T) -> bool {
|
|
loop {
|
|
match (a.next(), b.next()) {
|
|
(None, None) => return true,
|
|
(None, _ ) => return true,
|
|
(_ , None) => return false,
|
|
(Some(x), Some(y)) => if x.ne(&y) { return x.le(&y) },
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Return `a` > `b` lexicographically (Using partial order, `Ord`)
|
|
pub fn gt<A: Eq + Ord, T: Iterator<A>>(mut a: T, mut b: T) -> bool {
|
|
loop {
|
|
match (a.next(), b.next()) {
|
|
(None, None) => return false,
|
|
(None, _ ) => return false,
|
|
(_ , None) => return true,
|
|
(Some(x), Some(y)) => if x.ne(&y) { return x.gt(&y) },
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Return `a` >= `b` lexicographically (Using partial order, `Ord`)
|
|
pub fn ge<A: Eq + Ord, T: Iterator<A>>(mut a: T, mut b: T) -> bool {
|
|
loop {
|
|
match (a.next(), b.next()) {
|
|
(None, None) => return true,
|
|
(None, _ ) => return false,
|
|
(_ , None) => return true,
|
|
(Some(x), Some(y)) => if x.ne(&y) { return x.ge(&y) },
|
|
}
|
|
}
|
|
}
|
|
|
|
#[test]
|
|
fn test_lt() {
|
|
use vec::ImmutableVector;
|
|
|
|
let empty: [int, ..0] = [];
|
|
let xs = [1,2,3];
|
|
let ys = [1,2,0];
|
|
|
|
assert!(!lt(xs.iter(), ys.iter()));
|
|
assert!(!le(xs.iter(), ys.iter()));
|
|
assert!( gt(xs.iter(), ys.iter()));
|
|
assert!( ge(xs.iter(), ys.iter()));
|
|
|
|
assert!( lt(ys.iter(), xs.iter()));
|
|
assert!( le(ys.iter(), xs.iter()));
|
|
assert!(!gt(ys.iter(), xs.iter()));
|
|
assert!(!ge(ys.iter(), xs.iter()));
|
|
|
|
assert!( lt(empty.iter(), xs.iter()));
|
|
assert!( le(empty.iter(), xs.iter()));
|
|
assert!(!gt(empty.iter(), xs.iter()));
|
|
assert!(!ge(empty.iter(), xs.iter()));
|
|
|
|
// Sequence with NaN
|
|
let u = [1.0, 2.0];
|
|
let v = [0.0/0.0, 3.0];
|
|
|
|
assert!(!lt(u.iter(), v.iter()));
|
|
assert!(!le(u.iter(), v.iter()));
|
|
assert!(!gt(u.iter(), v.iter()));
|
|
assert!(!ge(u.iter(), v.iter()));
|
|
|
|
let a = [0.0/0.0];
|
|
let b = [1.0];
|
|
let c = [2.0];
|
|
|
|
assert!(lt(a.iter(), b.iter()) == (a[0] < b[0]));
|
|
assert!(le(a.iter(), b.iter()) == (a[0] <= b[0]));
|
|
assert!(gt(a.iter(), b.iter()) == (a[0] > b[0]));
|
|
assert!(ge(a.iter(), b.iter()) == (a[0] >= b[0]));
|
|
|
|
assert!(lt(c.iter(), b.iter()) == (c[0] < b[0]));
|
|
assert!(le(c.iter(), b.iter()) == (c[0] <= b[0]));
|
|
assert!(gt(c.iter(), b.iter()) == (c[0] > b[0]));
|
|
assert!(ge(c.iter(), b.iter()) == (c[0] >= b[0]));
|
|
}
|
|
}
|
|
|
|
#[cfg(test)]
|
|
mod tests {
|
|
use super::*;
|
|
use prelude::*;
|
|
|
|
use cmp;
|
|
use uint;
|
|
use num;
|
|
|
|
#[test]
|
|
fn test_counter_from_iter() {
|
|
let mut it = count(0, 5).take(10);
|
|
let xs: ~[int] = FromIterator::from_iterator(&mut it);
|
|
assert_eq!(xs, ~[0, 5, 10, 15, 20, 25, 30, 35, 40, 45]);
|
|
}
|
|
|
|
#[test]
|
|
fn test_iterator_chain() {
|
|
let xs = [0u, 1, 2, 3, 4, 5];
|
|
let ys = [30u, 40, 50, 60];
|
|
let expected = [0, 1, 2, 3, 4, 5, 30, 40, 50, 60];
|
|
let mut it = xs.iter().chain(ys.iter());
|
|
let mut i = 0;
|
|
for &x in it {
|
|
assert_eq!(x, expected[i]);
|
|
i += 1;
|
|
}
|
|
assert_eq!(i, expected.len());
|
|
|
|
let ys = count(30u, 10).take(4);
|
|
let mut it = xs.iter().map(|&x| x).chain(ys);
|
|
let mut i = 0;
|
|
for x in it {
|
|
assert_eq!(x, expected[i]);
|
|
i += 1;
|
|
}
|
|
assert_eq!(i, expected.len());
|
|
}
|
|
|
|
#[test]
|
|
fn test_filter_map() {
|
|
let mut it = count(0u, 1u).take(10)
|
|
.filter_map(|x| if x.is_even() { Some(x*x) } else { None });
|
|
assert_eq!(it.collect::<~[uint]>(), ~[0*0, 2*2, 4*4, 6*6, 8*8]);
|
|
}
|
|
|
|
#[test]
|
|
fn test_iterator_enumerate() {
|
|
let xs = [0u, 1, 2, 3, 4, 5];
|
|
let mut it = xs.iter().enumerate();
|
|
for (i, &x) in it {
|
|
assert_eq!(i, x);
|
|
}
|
|
}
|
|
|
|
#[test]
|
|
fn test_iterator_peekable() {
|
|
let xs = ~[0u, 1, 2, 3, 4, 5];
|
|
let mut it = xs.iter().map(|&x|x).peekable();
|
|
assert_eq!(it.peek().unwrap(), &0);
|
|
assert_eq!(it.next().unwrap(), 0);
|
|
assert_eq!(it.next().unwrap(), 1);
|
|
assert_eq!(it.next().unwrap(), 2);
|
|
assert_eq!(it.peek().unwrap(), &3);
|
|
assert_eq!(it.peek().unwrap(), &3);
|
|
assert_eq!(it.next().unwrap(), 3);
|
|
assert_eq!(it.next().unwrap(), 4);
|
|
assert_eq!(it.peek().unwrap(), &5);
|
|
assert_eq!(it.next().unwrap(), 5);
|
|
assert!(it.peek().is_none());
|
|
assert!(it.next().is_none());
|
|
}
|
|
|
|
#[test]
|
|
fn test_iterator_take_while() {
|
|
let xs = [0u, 1, 2, 3, 5, 13, 15, 16, 17, 19];
|
|
let ys = [0u, 1, 2, 3, 5, 13];
|
|
let mut it = xs.iter().take_while(|&x| *x < 15u);
|
|
let mut i = 0;
|
|
for &x in it {
|
|
assert_eq!(x, ys[i]);
|
|
i += 1;
|
|
}
|
|
assert_eq!(i, ys.len());
|
|
}
|
|
|
|
#[test]
|
|
fn test_iterator_skip_while() {
|
|
let xs = [0u, 1, 2, 3, 5, 13, 15, 16, 17, 19];
|
|
let ys = [15, 16, 17, 19];
|
|
let mut it = xs.iter().skip_while(|&x| *x < 15u);
|
|
let mut i = 0;
|
|
for &x in it {
|
|
assert_eq!(x, ys[i]);
|
|
i += 1;
|
|
}
|
|
assert_eq!(i, ys.len());
|
|
}
|
|
|
|
#[test]
|
|
fn test_iterator_skip() {
|
|
let xs = [0u, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30];
|
|
let ys = [13, 15, 16, 17, 19, 20, 30];
|
|
let mut it = xs.iter().skip(5);
|
|
let mut i = 0;
|
|
for &x in it {
|
|
assert_eq!(x, ys[i]);
|
|
i += 1;
|
|
}
|
|
assert_eq!(i, ys.len());
|
|
}
|
|
|
|
#[test]
|
|
fn test_iterator_take() {
|
|
let xs = [0u, 1, 2, 3, 5, 13, 15, 16, 17, 19];
|
|
let ys = [0u, 1, 2, 3, 5];
|
|
let mut it = xs.iter().take(5);
|
|
let mut i = 0;
|
|
for &x in it {
|
|
assert_eq!(x, ys[i]);
|
|
i += 1;
|
|
}
|
|
assert_eq!(i, ys.len());
|
|
}
|
|
|
|
#[test]
|
|
fn test_iterator_scan() {
|
|
// test the type inference
|
|
fn add(old: &mut int, new: &uint) -> Option<f64> {
|
|
*old += *new as int;
|
|
Some(*old as f64)
|
|
}
|
|
let xs = [0u, 1, 2, 3, 4];
|
|
let ys = [0f64, 1.0, 3.0, 6.0, 10.0];
|
|
|
|
let mut it = xs.iter().scan(0, add);
|
|
let mut i = 0;
|
|
for x in it {
|
|
assert_eq!(x, ys[i]);
|
|
i += 1;
|
|
}
|
|
assert_eq!(i, ys.len());
|
|
}
|
|
|
|
#[test]
|
|
fn test_iterator_flat_map() {
|
|
let xs = [0u, 3, 6];
|
|
let ys = [0u, 1, 2, 3, 4, 5, 6, 7, 8];
|
|
let mut it = xs.iter().flat_map(|&x| count(x, 1).take(3));
|
|
let mut i = 0;
|
|
for x in it {
|
|
assert_eq!(x, ys[i]);
|
|
i += 1;
|
|
}
|
|
assert_eq!(i, ys.len());
|
|
}
|
|
|
|
#[test]
|
|
fn test_inspect() {
|
|
let xs = [1u, 2, 3, 4];
|
|
let mut n = 0;
|
|
|
|
let ys = xs.iter()
|
|
.map(|&x| x)
|
|
.inspect(|_| n += 1)
|
|
.collect::<~[uint]>();
|
|
|
|
assert_eq!(n, xs.len());
|
|
assert_eq!(xs, ys.as_slice());
|
|
}
|
|
|
|
#[test]
|
|
fn test_unfoldr() {
|
|
fn count(st: &mut uint) -> Option<uint> {
|
|
if *st < 10 {
|
|
let ret = Some(*st);
|
|
*st += 1;
|
|
ret
|
|
} else {
|
|
None
|
|
}
|
|
}
|
|
|
|
let mut it = Unfold::new(0, count);
|
|
let mut i = 0;
|
|
for counted in it {
|
|
assert_eq!(counted, i);
|
|
i += 1;
|
|
}
|
|
assert_eq!(i, 10);
|
|
}
|
|
|
|
#[test]
|
|
fn test_cycle() {
|
|
let cycle_len = 3;
|
|
let it = count(0u, 1).take(cycle_len).cycle();
|
|
assert_eq!(it.size_hint(), (uint::max_value, None));
|
|
for (i, x) in it.take(100).enumerate() {
|
|
assert_eq!(i % cycle_len, x);
|
|
}
|
|
|
|
let mut it = count(0u, 1).take(0).cycle();
|
|
assert_eq!(it.size_hint(), (0, Some(0)));
|
|
assert_eq!(it.next(), None);
|
|
}
|
|
|
|
#[test]
|
|
fn test_iterator_nth() {
|
|
let v = &[0, 1, 2, 3, 4];
|
|
for i in range(0u, v.len()) {
|
|
assert_eq!(v.iter().nth(i).unwrap(), &v[i]);
|
|
}
|
|
}
|
|
|
|
#[test]
|
|
fn test_iterator_last() {
|
|
let v = &[0, 1, 2, 3, 4];
|
|
assert_eq!(v.iter().last().unwrap(), &4);
|
|
assert_eq!(v.slice(0, 1).iter().last().unwrap(), &0);
|
|
}
|
|
|
|
#[test]
|
|
fn test_iterator_len() {
|
|
let v = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
|
|
assert_eq!(v.slice(0, 4).iter().len(), 4);
|
|
assert_eq!(v.slice(0, 10).iter().len(), 10);
|
|
assert_eq!(v.slice(0, 0).iter().len(), 0);
|
|
}
|
|
|
|
#[test]
|
|
fn test_iterator_sum() {
|
|
let v = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
|
|
assert_eq!(v.slice(0, 4).iter().map(|&x| x).sum(), 6);
|
|
assert_eq!(v.iter().map(|&x| x).sum(), 55);
|
|
assert_eq!(v.slice(0, 0).iter().map(|&x| x).sum(), 0);
|
|
}
|
|
|
|
#[test]
|
|
fn test_iterator_product() {
|
|
let v = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
|
|
assert_eq!(v.slice(0, 4).iter().map(|&x| x).product(), 0);
|
|
assert_eq!(v.slice(1, 5).iter().map(|&x| x).product(), 24);
|
|
assert_eq!(v.slice(0, 0).iter().map(|&x| x).product(), 1);
|
|
}
|
|
|
|
#[test]
|
|
fn test_iterator_max() {
|
|
let v = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
|
|
assert_eq!(v.slice(0, 4).iter().map(|&x| x).max(), Some(3));
|
|
assert_eq!(v.iter().map(|&x| x).max(), Some(10));
|
|
assert_eq!(v.slice(0, 0).iter().map(|&x| x).max(), None);
|
|
}
|
|
|
|
#[test]
|
|
fn test_iterator_min() {
|
|
let v = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
|
|
assert_eq!(v.slice(0, 4).iter().map(|&x| x).min(), Some(0));
|
|
assert_eq!(v.iter().map(|&x| x).min(), Some(0));
|
|
assert_eq!(v.slice(0, 0).iter().map(|&x| x).min(), None);
|
|
}
|
|
|
|
#[test]
|
|
fn test_iterator_size_hint() {
|
|
let c = count(0, 1);
|
|
let v = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
|
|
let v2 = &[10, 11, 12];
|
|
let vi = v.iter();
|
|
|
|
assert_eq!(c.size_hint(), (uint::max_value, None));
|
|
assert_eq!(vi.size_hint(), (10, Some(10)));
|
|
|
|
assert_eq!(c.take(5).size_hint(), (5, Some(5)));
|
|
assert_eq!(c.skip(5).size_hint().second(), None);
|
|
assert_eq!(c.take_while(|_| false).size_hint(), (0, None));
|
|
assert_eq!(c.skip_while(|_| false).size_hint(), (0, None));
|
|
assert_eq!(c.enumerate().size_hint(), (uint::max_value, None));
|
|
assert_eq!(c.chain(vi.map(|&i| i)).size_hint(), (uint::max_value, None));
|
|
assert_eq!(c.zip(vi).size_hint(), (10, Some(10)));
|
|
assert_eq!(c.scan(0, |_,_| Some(0)).size_hint(), (0, None));
|
|
assert_eq!(c.filter(|_| false).size_hint(), (0, None));
|
|
assert_eq!(c.map(|_| 0).size_hint(), (uint::max_value, None));
|
|
assert_eq!(c.filter_map(|_| Some(0)).size_hint(), (0, None));
|
|
|
|
assert_eq!(vi.take(5).size_hint(), (5, Some(5)));
|
|
assert_eq!(vi.take(12).size_hint(), (10, Some(10)));
|
|
assert_eq!(vi.skip(3).size_hint(), (7, Some(7)));
|
|
assert_eq!(vi.skip(12).size_hint(), (0, Some(0)));
|
|
assert_eq!(vi.take_while(|_| false).size_hint(), (0, Some(10)));
|
|
assert_eq!(vi.skip_while(|_| false).size_hint(), (0, Some(10)));
|
|
assert_eq!(vi.enumerate().size_hint(), (10, Some(10)));
|
|
assert_eq!(vi.chain(v2.iter()).size_hint(), (13, Some(13)));
|
|
assert_eq!(vi.zip(v2.iter()).size_hint(), (3, Some(3)));
|
|
assert_eq!(vi.scan(0, |_,_| Some(0)).size_hint(), (0, Some(10)));
|
|
assert_eq!(vi.filter(|_| false).size_hint(), (0, Some(10)));
|
|
assert_eq!(vi.map(|i| i+1).size_hint(), (10, Some(10)));
|
|
assert_eq!(vi.filter_map(|_| Some(0)).size_hint(), (0, Some(10)));
|
|
}
|
|
|
|
#[test]
|
|
fn test_collect() {
|
|
let a = ~[1, 2, 3, 4, 5];
|
|
let b: ~[int] = a.iter().map(|&x| x).collect();
|
|
assert_eq!(a, b);
|
|
}
|
|
|
|
#[test]
|
|
fn test_all() {
|
|
let v: ~&[int] = ~&[1, 2, 3, 4, 5];
|
|
assert!(v.iter().all(|&x| x < 10));
|
|
assert!(!v.iter().all(|&x| x.is_even()));
|
|
assert!(!v.iter().all(|&x| x > 100));
|
|
assert!(v.slice(0, 0).iter().all(|_| fail!()));
|
|
}
|
|
|
|
#[test]
|
|
fn test_any() {
|
|
let v: ~&[int] = ~&[1, 2, 3, 4, 5];
|
|
assert!(v.iter().any(|&x| x < 10));
|
|
assert!(v.iter().any(|&x| x.is_even()));
|
|
assert!(!v.iter().any(|&x| x > 100));
|
|
assert!(!v.slice(0, 0).iter().any(|_| fail!()));
|
|
}
|
|
|
|
#[test]
|
|
fn test_find() {
|
|
let v: &[int] = &[1, 3, 9, 27, 103, 14, 11];
|
|
assert_eq!(*v.iter().find(|x| *x & 1 == 0).unwrap(), 14);
|
|
assert_eq!(*v.iter().find(|x| *x % 3 == 0).unwrap(), 3);
|
|
assert!(v.iter().find(|x| *x % 12 == 0).is_none());
|
|
}
|
|
|
|
#[test]
|
|
fn test_position() {
|
|
let v = &[1, 3, 9, 27, 103, 14, 11];
|
|
assert_eq!(v.iter().position(|x| *x & 1 == 0).unwrap(), 5);
|
|
assert_eq!(v.iter().position(|x| *x % 3 == 0).unwrap(), 1);
|
|
assert!(v.iter().position(|x| *x % 12 == 0).is_none());
|
|
}
|
|
|
|
#[test]
|
|
fn test_count() {
|
|
let xs = &[1, 2, 2, 1, 5, 9, 0, 2];
|
|
assert_eq!(xs.iter().count(|x| *x == 2), 3);
|
|
assert_eq!(xs.iter().count(|x| *x == 5), 1);
|
|
assert_eq!(xs.iter().count(|x| *x == 95), 0);
|
|
}
|
|
|
|
#[test]
|
|
fn test_max_by() {
|
|
let xs: &[int] = &[-3, 0, 1, 5, -10];
|
|
assert_eq!(*xs.iter().max_by(|x| x.abs()).unwrap(), -10);
|
|
}
|
|
|
|
#[test]
|
|
fn test_min_by() {
|
|
let xs: &[int] = &[-3, 0, 1, 5, -10];
|
|
assert_eq!(*xs.iter().min_by(|x| x.abs()).unwrap(), 0);
|
|
}
|
|
|
|
#[test]
|
|
fn test_by_ref() {
|
|
let mut xs = range(0, 10);
|
|
// sum the first five values
|
|
let partial_sum = xs.by_ref().take(5).fold(0, |a, b| a + b);
|
|
assert_eq!(partial_sum, 10);
|
|
assert_eq!(xs.next(), Some(5));
|
|
}
|
|
|
|
#[test]
|
|
fn test_invert() {
|
|
let xs = [2, 4, 6, 8, 10, 12, 14, 16];
|
|
let mut it = xs.iter();
|
|
it.next();
|
|
it.next();
|
|
assert_eq!(it.invert().map(|&x| x).collect::<~[int]>(), ~[16, 14, 12, 10, 8, 6]);
|
|
}
|
|
|
|
#[test]
|
|
fn test_double_ended_map() {
|
|
let xs = [1, 2, 3, 4, 5, 6];
|
|
let mut it = xs.iter().map(|&x| x * -1);
|
|
assert_eq!(it.next(), Some(-1));
|
|
assert_eq!(it.next(), Some(-2));
|
|
assert_eq!(it.next_back(), Some(-6));
|
|
assert_eq!(it.next_back(), Some(-5));
|
|
assert_eq!(it.next(), Some(-3));
|
|
assert_eq!(it.next_back(), Some(-4));
|
|
assert_eq!(it.next(), None);
|
|
}
|
|
|
|
#[test]
|
|
fn test_double_ended_enumerate() {
|
|
let xs = [1, 2, 3, 4, 5, 6];
|
|
let mut it = xs.iter().map(|&x| x).enumerate();
|
|
assert_eq!(it.next(), Some((0, 1)));
|
|
assert_eq!(it.next(), Some((1, 2)));
|
|
assert_eq!(it.next_back(), Some((5, 6)));
|
|
assert_eq!(it.next_back(), Some((4, 5)));
|
|
assert_eq!(it.next_back(), Some((3, 4)));
|
|
assert_eq!(it.next_back(), Some((2, 3)));
|
|
assert_eq!(it.next(), None);
|
|
}
|
|
|
|
#[test]
|
|
fn test_double_ended_zip() {
|
|
let xs = [1, 2, 3, 4, 5, 6];
|
|
let ys = [1, 2, 3, 7];
|
|
let a = xs.iter().map(|&x| x);
|
|
let b = ys.iter().map(|&x| x);
|
|
let mut it = a.zip(b);
|
|
assert_eq!(it.next(), Some((1, 1)));
|
|
assert_eq!(it.next(), Some((2, 2)));
|
|
assert_eq!(it.next_back(), Some((4, 7)));
|
|
assert_eq!(it.next_back(), Some((3, 3)));
|
|
assert_eq!(it.next(), None);
|
|
}
|
|
|
|
#[test]
|
|
fn test_double_ended_filter() {
|
|
let xs = [1, 2, 3, 4, 5, 6];
|
|
let mut it = xs.iter().filter(|&x| *x & 1 == 0);
|
|
assert_eq!(it.next_back().unwrap(), &6);
|
|
assert_eq!(it.next_back().unwrap(), &4);
|
|
assert_eq!(it.next().unwrap(), &2);
|
|
assert_eq!(it.next_back(), None);
|
|
}
|
|
|
|
#[test]
|
|
fn test_double_ended_filter_map() {
|
|
let xs = [1, 2, 3, 4, 5, 6];
|
|
let mut it = xs.iter().filter_map(|&x| if x & 1 == 0 { Some(x * 2) } else { None });
|
|
assert_eq!(it.next_back().unwrap(), 12);
|
|
assert_eq!(it.next_back().unwrap(), 8);
|
|
assert_eq!(it.next().unwrap(), 4);
|
|
assert_eq!(it.next_back(), None);
|
|
}
|
|
|
|
#[test]
|
|
fn test_double_ended_chain() {
|
|
let xs = [1, 2, 3, 4, 5];
|
|
let ys = ~[7, 9, 11];
|
|
let mut it = xs.iter().chain(ys.iter()).invert();
|
|
assert_eq!(it.next().unwrap(), &11)
|
|
assert_eq!(it.next().unwrap(), &9)
|
|
assert_eq!(it.next_back().unwrap(), &1)
|
|
assert_eq!(it.next_back().unwrap(), &2)
|
|
assert_eq!(it.next_back().unwrap(), &3)
|
|
assert_eq!(it.next_back().unwrap(), &4)
|
|
assert_eq!(it.next_back().unwrap(), &5)
|
|
assert_eq!(it.next_back().unwrap(), &7)
|
|
assert_eq!(it.next_back(), None)
|
|
}
|
|
|
|
#[test]
|
|
fn test_rposition() {
|
|
fn f(xy: &(int, char)) -> bool { let (_x, y) = *xy; y == 'b' }
|
|
fn g(xy: &(int, char)) -> bool { let (_x, y) = *xy; y == 'd' }
|
|
let v = ~[(0, 'a'), (1, 'b'), (2, 'c'), (3, 'b')];
|
|
|
|
assert_eq!(v.iter().rposition(f), Some(3u));
|
|
assert!(v.iter().rposition(g).is_none());
|
|
}
|
|
|
|
#[test]
|
|
#[should_fail]
|
|
fn test_rposition_fail() {
|
|
let v = [(~0, @0), (~0, @0), (~0, @0), (~0, @0)];
|
|
let mut i = 0;
|
|
v.iter().rposition(|_elt| {
|
|
if i == 2 {
|
|
fail!()
|
|
}
|
|
i += 1;
|
|
false
|
|
});
|
|
}
|
|
|
|
|
|
#[cfg(test)]
|
|
fn check_randacc_iter<A: Eq, T: Clone + RandomAccessIterator<A>>(a: T, len: uint)
|
|
{
|
|
let mut b = a.clone();
|
|
assert_eq!(len, b.indexable());
|
|
let mut n = 0;
|
|
for (i, elt) in a.enumerate() {
|
|
assert_eq!(Some(elt), b.idx(i));
|
|
n += 1;
|
|
}
|
|
assert_eq!(n, len);
|
|
assert_eq!(None, b.idx(n));
|
|
// call recursively to check after picking off an element
|
|
if len > 0 {
|
|
b.next();
|
|
check_randacc_iter(b, len-1);
|
|
}
|
|
}
|
|
|
|
|
|
#[test]
|
|
fn test_double_ended_flat_map() {
|
|
let u = [0u,1];
|
|
let v = [5,6,7,8];
|
|
let mut it = u.iter().flat_map(|x| v.slice(*x, v.len()).iter());
|
|
assert_eq!(it.next_back().unwrap(), &8);
|
|
assert_eq!(it.next().unwrap(), &5);
|
|
assert_eq!(it.next_back().unwrap(), &7);
|
|
assert_eq!(it.next_back().unwrap(), &6);
|
|
assert_eq!(it.next_back().unwrap(), &8);
|
|
assert_eq!(it.next().unwrap(), &6);
|
|
assert_eq!(it.next_back().unwrap(), &7);
|
|
assert_eq!(it.next_back(), None);
|
|
assert_eq!(it.next(), None);
|
|
assert_eq!(it.next_back(), None);
|
|
}
|
|
|
|
#[test]
|
|
fn test_random_access_chain() {
|
|
let xs = [1, 2, 3, 4, 5];
|
|
let ys = ~[7, 9, 11];
|
|
let mut it = xs.iter().chain(ys.iter());
|
|
assert_eq!(it.idx(0).unwrap(), &1);
|
|
assert_eq!(it.idx(5).unwrap(), &7);
|
|
assert_eq!(it.idx(7).unwrap(), &11);
|
|
assert!(it.idx(8).is_none());
|
|
|
|
it.next();
|
|
it.next();
|
|
it.next_back();
|
|
|
|
assert_eq!(it.idx(0).unwrap(), &3);
|
|
assert_eq!(it.idx(4).unwrap(), &9);
|
|
assert!(it.idx(6).is_none());
|
|
|
|
check_randacc_iter(it, xs.len() + ys.len() - 3);
|
|
}
|
|
|
|
#[test]
|
|
fn test_random_access_enumerate() {
|
|
let xs = [1, 2, 3, 4, 5];
|
|
check_randacc_iter(xs.iter().enumerate(), xs.len());
|
|
}
|
|
|
|
#[test]
|
|
fn test_random_access_invert() {
|
|
let xs = [1, 2, 3, 4, 5];
|
|
check_randacc_iter(xs.iter().invert(), xs.len());
|
|
let mut it = xs.iter().invert();
|
|
it.next();
|
|
it.next_back();
|
|
it.next();
|
|
check_randacc_iter(it, xs.len() - 3);
|
|
}
|
|
|
|
#[test]
|
|
fn test_random_access_zip() {
|
|
let xs = [1, 2, 3, 4, 5];
|
|
let ys = [7, 9, 11];
|
|
check_randacc_iter(xs.iter().zip(ys.iter()), cmp::min(xs.len(), ys.len()));
|
|
}
|
|
|
|
#[test]
|
|
fn test_random_access_take() {
|
|
let xs = [1, 2, 3, 4, 5];
|
|
let empty: &[int] = [];
|
|
check_randacc_iter(xs.iter().take(3), 3);
|
|
check_randacc_iter(xs.iter().take(20), xs.len());
|
|
check_randacc_iter(xs.iter().take(0), 0);
|
|
check_randacc_iter(empty.iter().take(2), 0);
|
|
}
|
|
|
|
#[test]
|
|
fn test_random_access_skip() {
|
|
let xs = [1, 2, 3, 4, 5];
|
|
let empty: &[int] = [];
|
|
check_randacc_iter(xs.iter().skip(2), xs.len() - 2);
|
|
check_randacc_iter(empty.iter().skip(2), 0);
|
|
}
|
|
|
|
#[test]
|
|
fn test_random_access_inspect() {
|
|
let xs = [1, 2, 3, 4, 5];
|
|
|
|
// test .map and .inspect that don't implement Clone
|
|
let it = xs.iter().inspect(|_| {});
|
|
assert_eq!(xs.len(), it.indexable());
|
|
for (i, elt) in xs.iter().enumerate() {
|
|
assert_eq!(Some(elt), it.idx(i));
|
|
}
|
|
|
|
}
|
|
|
|
#[test]
|
|
fn test_random_access_map() {
|
|
let xs = [1, 2, 3, 4, 5];
|
|
|
|
let it = xs.iter().map(|x| *x);
|
|
assert_eq!(xs.len(), it.indexable());
|
|
for (i, elt) in xs.iter().enumerate() {
|
|
assert_eq!(Some(*elt), it.idx(i));
|
|
}
|
|
}
|
|
|
|
#[test]
|
|
fn test_random_access_cycle() {
|
|
let xs = [1, 2, 3, 4, 5];
|
|
let empty: &[int] = [];
|
|
check_randacc_iter(xs.iter().cycle().take(27), 27);
|
|
check_randacc_iter(empty.iter().cycle(), 0);
|
|
}
|
|
|
|
#[test]
|
|
fn test_double_ended_range() {
|
|
assert_eq!(range(11i, 14).invert().collect::<~[int]>(), ~[13i, 12, 11]);
|
|
for _ in range(10i, 0).invert() {
|
|
fail!("unreachable");
|
|
}
|
|
|
|
assert_eq!(range(11u, 14).invert().collect::<~[uint]>(), ~[13u, 12, 11]);
|
|
for _ in range(10u, 0).invert() {
|
|
fail!("unreachable");
|
|
}
|
|
}
|
|
|
|
#[test]
|
|
fn test_range() {
|
|
/// A mock type to check Range when ToPrimitive returns None
|
|
struct Foo;
|
|
|
|
impl ToPrimitive for Foo {
|
|
fn to_i64(&self) -> Option<i64> { None }
|
|
fn to_u64(&self) -> Option<u64> { None }
|
|
}
|
|
|
|
impl Add<Foo, Foo> for Foo {
|
|
fn add(&self, _: &Foo) -> Foo {
|
|
Foo
|
|
}
|
|
}
|
|
|
|
impl Ord for Foo {
|
|
fn lt(&self, _: &Foo) -> bool {
|
|
false
|
|
}
|
|
}
|
|
|
|
impl Clone for Foo {
|
|
fn clone(&self) -> Foo {
|
|
Foo
|
|
}
|
|
}
|
|
|
|
impl num::One for Foo {
|
|
fn one() -> Foo {
|
|
Foo
|
|
}
|
|
}
|
|
|
|
assert_eq!(range(0i, 5).collect::<~[int]>(), ~[0i, 1, 2, 3, 4]);
|
|
assert_eq!(range(-10i, -1).collect::<~[int]>(), ~[-10, -9, -8, -7, -6, -5, -4, -3, -2]);
|
|
assert_eq!(range(0i, 5).invert().collect::<~[int]>(), ~[4, 3, 2, 1, 0]);
|
|
assert_eq!(range(200, -5).collect::<~[int]>(), ~[]);
|
|
assert_eq!(range(200, -5).invert().collect::<~[int]>(), ~[]);
|
|
assert_eq!(range(200, 200).collect::<~[int]>(), ~[]);
|
|
assert_eq!(range(200, 200).invert().collect::<~[int]>(), ~[]);
|
|
|
|
assert_eq!(range(0i, 100).size_hint(), (100, Some(100)));
|
|
// this test is only meaningful when sizeof uint < sizeof u64
|
|
assert_eq!(range(uint::max_value - 1, uint::max_value).size_hint(), (1, Some(1)));
|
|
assert_eq!(range(-10i, -1).size_hint(), (9, Some(9)));
|
|
assert_eq!(range(Foo, Foo).size_hint(), (0, None));
|
|
}
|
|
|
|
#[test]
|
|
fn test_range_inclusive() {
|
|
assert_eq!(range_inclusive(0i, 5).collect::<~[int]>(), ~[0i, 1, 2, 3, 4, 5]);
|
|
assert_eq!(range_inclusive(0i, 5).invert().collect::<~[int]>(), ~[5i, 4, 3, 2, 1, 0]);
|
|
assert_eq!(range_inclusive(200, -5).collect::<~[int]>(), ~[]);
|
|
assert_eq!(range_inclusive(200, -5).invert().collect::<~[int]>(), ~[]);
|
|
assert_eq!(range_inclusive(200, 200).collect::<~[int]>(), ~[200]);
|
|
assert_eq!(range_inclusive(200, 200).invert().collect::<~[int]>(), ~[200]);
|
|
}
|
|
|
|
#[test]
|
|
fn test_range_step() {
|
|
assert_eq!(range_step(0i, 20, 5).collect::<~[int]>(), ~[0, 5, 10, 15]);
|
|
assert_eq!(range_step(20i, 0, -5).collect::<~[int]>(), ~[20, 15, 10, 5]);
|
|
assert_eq!(range_step(20i, 0, -6).collect::<~[int]>(), ~[20, 14, 8, 2]);
|
|
assert_eq!(range_step(200u8, 255, 50).collect::<~[u8]>(), ~[200u8, 250]);
|
|
assert_eq!(range_step(200, -5, 1).collect::<~[int]>(), ~[]);
|
|
assert_eq!(range_step(200, 200, 1).collect::<~[int]>(), ~[]);
|
|
}
|
|
|
|
#[test]
|
|
fn test_range_step_inclusive() {
|
|
assert_eq!(range_step_inclusive(0i, 20, 5).collect::<~[int]>(), ~[0, 5, 10, 15, 20]);
|
|
assert_eq!(range_step_inclusive(20i, 0, -5).collect::<~[int]>(), ~[20, 15, 10, 5, 0]);
|
|
assert_eq!(range_step_inclusive(20i, 0, -6).collect::<~[int]>(), ~[20, 14, 8, 2]);
|
|
assert_eq!(range_step_inclusive(200u8, 255, 50).collect::<~[u8]>(), ~[200u8, 250]);
|
|
assert_eq!(range_step_inclusive(200, -5, 1).collect::<~[int]>(), ~[]);
|
|
assert_eq!(range_step_inclusive(200, 200, 1).collect::<~[int]>(), ~[200]);
|
|
}
|
|
|
|
#[test]
|
|
fn test_reverse() {
|
|
let mut ys = [1, 2, 3, 4, 5];
|
|
ys.mut_iter().reverse_();
|
|
assert_eq!(ys, [5, 4, 3, 2, 1]);
|
|
}
|
|
}
|