/
set.rs
669 lines (589 loc) · 20.5 KB
/
set.rs
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// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
// This is pretty much entirely stolen from TreeSet, since BTreeMap has an identical interface
// to TreeMap
use core::prelude::*;
use btree_map::{BTreeMap, Keys, MoveEntries};
use std::hash::Hash;
use core::borrow::BorrowFrom;
use core::default::Default;
use core::{iter, fmt};
use core::iter::Peekable;
use core::fmt::Show;
// FIXME(conventions): implement bounded iterators
/// A set based on a B-Tree.
///
/// See BTreeMap's documentation for a detailed discussion of this collection's performance
/// benefits and drawbacks.
#[deriving(Clone, Hash, PartialEq, Eq, Ord, PartialOrd)]
pub struct BTreeSet<T>{
map: BTreeMap<T, ()>,
}
/// An iterator over a BTreeSet's items.
pub type Items<'a, T> = Keys<'a, T, ()>;
/// An owning iterator over a BTreeSet's items.
pub type MoveItems<T> = iter::Map<'static, (T, ()), T, MoveEntries<T, ()>>;
/// A lazy iterator producing elements in the set difference (in-order).
pub struct DifferenceItems<'a, T:'a> {
a: Peekable<&'a T, Items<'a, T>>,
b: Peekable<&'a T, Items<'a, T>>,
}
/// A lazy iterator producing elements in the set symmetric difference (in-order).
pub struct SymDifferenceItems<'a, T:'a> {
a: Peekable<&'a T, Items<'a, T>>,
b: Peekable<&'a T, Items<'a, T>>,
}
/// A lazy iterator producing elements in the set intersection (in-order).
pub struct IntersectionItems<'a, T:'a> {
a: Peekable<&'a T, Items<'a, T>>,
b: Peekable<&'a T, Items<'a, T>>,
}
/// A lazy iterator producing elements in the set union (in-order).
pub struct UnionItems<'a, T:'a> {
a: Peekable<&'a T, Items<'a, T>>,
b: Peekable<&'a T, Items<'a, T>>,
}
impl<T: Ord> BTreeSet<T> {
/// Makes a new BTreeSet with a reasonable choice of B.
#[unstable = "matches collection reform specification, waiting for dust to settle"]
pub fn new() -> BTreeSet<T> {
BTreeSet { map: BTreeMap::new() }
}
/// Makes a new BTreeSet with the given B.
///
/// B cannot be less than 2.
pub fn with_b(b: uint) -> BTreeSet<T> {
BTreeSet { map: BTreeMap::with_b(b) }
}
}
impl<T> BTreeSet<T> {
/// Gets an iterator over the BTreeSet's contents.
#[unstable = "matches collection reform specification, waiting for dust to settle"]
pub fn iter<'a>(&'a self) -> Items<'a, T> {
self.map.keys()
}
/// Gets an iterator for moving out the BtreeSet's contents.
#[unstable = "matches collection reform specification, waiting for dust to settle"]
pub fn into_iter(self) -> MoveItems<T> {
self.map.into_iter().map(|(k, _)| k)
}
}
impl<T: Ord> BTreeSet<T> {
/// Visits the values representing the difference, in ascending order.
#[unstable = "matches collection reform specification, waiting for dust to settle"]
pub fn difference<'a>(&'a self, other: &'a BTreeSet<T>) -> DifferenceItems<'a, T> {
DifferenceItems{a: self.iter().peekable(), b: other.iter().peekable()}
}
/// Visits the values representing the symmetric difference, in ascending order.
#[unstable = "matches collection reform specification, waiting for dust to settle"]
pub fn symmetric_difference<'a>(&'a self, other: &'a BTreeSet<T>)
-> SymDifferenceItems<'a, T> {
SymDifferenceItems{a: self.iter().peekable(), b: other.iter().peekable()}
}
/// Visits the values representing the intersection, in ascending order.
#[unstable = "matches collection reform specification, waiting for dust to settle"]
pub fn intersection<'a>(&'a self, other: &'a BTreeSet<T>)
-> IntersectionItems<'a, T> {
IntersectionItems{a: self.iter().peekable(), b: other.iter().peekable()}
}
/// Visits the values representing the union, in ascending order.
#[unstable = "matches collection reform specification, waiting for dust to settle"]
pub fn union<'a>(&'a self, other: &'a BTreeSet<T>) -> UnionItems<'a, T> {
UnionItems{a: self.iter().peekable(), b: other.iter().peekable()}
}
/// Return the number of elements in the set
///
/// # Example
///
/// ```
/// use std::collections::BTreeSet;
///
/// let mut v = BTreeSet::new();
/// assert_eq!(v.len(), 0);
/// v.insert(1i);
/// assert_eq!(v.len(), 1);
/// ```
#[unstable = "matches collection reform specification, waiting for dust to settle"]
pub fn len(&self) -> uint { self.map.len() }
/// Returns true if the set contains no elements
///
/// # Example
///
/// ```
/// use std::collections::BTreeSet;
///
/// let mut v = BTreeSet::new();
/// assert!(v.is_empty());
/// v.insert(1i);
/// assert!(!v.is_empty());
/// ```
#[unstable = "matches collection reform specification, waiting for dust to settle"]
pub fn is_empty(&self) -> bool { self.len() == 0 }
/// Clears the set, removing all values.
///
/// # Example
///
/// ```
/// use std::collections::BTreeSet;
///
/// let mut v = BTreeSet::new();
/// v.insert(1i);
/// v.clear();
/// assert!(v.is_empty());
/// ```
#[unstable = "matches collection reform specification, waiting for dust to settle"]
pub fn clear(&mut self) {
self.map.clear()
}
/// Returns `true` if the set contains a value.
///
/// The value may be any borrowed form of the set's value type,
/// but the ordering on the borrowed form *must* match the
/// ordering on the value type.
///
/// # Example
///
/// ```
/// use std::collections::BTreeSet;
///
/// let set: BTreeSet<int> = [1i, 2, 3].iter().map(|&x| x).collect();
/// assert_eq!(set.contains(&1), true);
/// assert_eq!(set.contains(&4), false);
/// ```
#[unstable = "matches collection reform specification, waiting for dust to settle"]
pub fn contains<Sized? Q>(&self, value: &Q) -> bool where Q: BorrowFrom<T> + Ord {
self.map.contains_key(value)
}
/// Returns `true` if the set has no elements in common with `other`.
/// This is equivalent to checking for an empty intersection.
///
/// # Example
///
/// ```
/// use std::collections::BTreeSet;
///
/// let a: BTreeSet<int> = [1i, 2, 3].iter().map(|&x| x).collect();
/// let mut b: BTreeSet<int> = BTreeSet::new();
///
/// assert_eq!(a.is_disjoint(&b), true);
/// b.insert(4);
/// assert_eq!(a.is_disjoint(&b), true);
/// b.insert(1);
/// assert_eq!(a.is_disjoint(&b), false);
/// ```
#[unstable = "matches collection reform specification, waiting for dust to settle"]
pub fn is_disjoint(&self, other: &BTreeSet<T>) -> bool {
self.intersection(other).next().is_none()
}
/// Returns `true` if the set is a subset of another.
///
/// # Example
///
/// ```
/// use std::collections::BTreeSet;
///
/// let sup: BTreeSet<int> = [1i, 2, 3].iter().map(|&x| x).collect();
/// let mut set: BTreeSet<int> = BTreeSet::new();
///
/// assert_eq!(set.is_subset(&sup), true);
/// set.insert(2);
/// assert_eq!(set.is_subset(&sup), true);
/// set.insert(4);
/// assert_eq!(set.is_subset(&sup), false);
/// ```
#[unstable = "matches collection reform specification, waiting for dust to settle"]
pub fn is_subset(&self, other: &BTreeSet<T>) -> bool {
// Stolen from TreeMap
let mut x = self.iter();
let mut y = other.iter();
let mut a = x.next();
let mut b = y.next();
while a.is_some() {
if b.is_none() {
return false;
}
let a1 = a.unwrap();
let b1 = b.unwrap();
match b1.cmp(a1) {
Less => (),
Greater => return false,
Equal => a = x.next(),
}
b = y.next();
}
true
}
/// Returns `true` if the set is a superset of another.
///
/// # Example
///
/// ```
/// use std::collections::BTreeSet;
///
/// let sub: BTreeSet<int> = [1i, 2].iter().map(|&x| x).collect();
/// let mut set: BTreeSet<int> = BTreeSet::new();
///
/// assert_eq!(set.is_superset(&sub), false);
///
/// set.insert(0);
/// set.insert(1);
/// assert_eq!(set.is_superset(&sub), false);
///
/// set.insert(2);
/// assert_eq!(set.is_superset(&sub), true);
/// ```
#[unstable = "matches collection reform specification, waiting for dust to settle"]
pub fn is_superset(&self, other: &BTreeSet<T>) -> bool {
other.is_subset(self)
}
/// Adds a value to the set. Returns `true` if the value was not already
/// present in the set.
///
/// # Example
///
/// ```
/// use std::collections::BTreeSet;
///
/// let mut set = BTreeSet::new();
///
/// assert_eq!(set.insert(2i), true);
/// assert_eq!(set.insert(2i), false);
/// assert_eq!(set.len(), 1);
/// ```
#[unstable = "matches collection reform specification, waiting for dust to settle"]
pub fn insert(&mut self, value: T) -> bool {
self.map.insert(value, ()).is_none()
}
/// Removes a value from the set. Returns `true` if the value was
/// present in the set.
///
/// The value may be any borrowed form of the set's value type,
/// but the ordering on the borrowed form *must* match the
/// ordering on the value type.
///
/// # Example
///
/// ```
/// use std::collections::BTreeSet;
///
/// let mut set = BTreeSet::new();
///
/// set.insert(2i);
/// assert_eq!(set.remove(&2), true);
/// assert_eq!(set.remove(&2), false);
/// ```
#[unstable = "matches collection reform specification, waiting for dust to settle"]
pub fn remove<Sized? Q>(&mut self, value: &Q) -> bool where Q: BorrowFrom<T> + Ord {
self.map.remove(value).is_some()
}
}
impl<T: Ord> FromIterator<T> for BTreeSet<T> {
fn from_iter<Iter: Iterator<T>>(iter: Iter) -> BTreeSet<T> {
let mut set = BTreeSet::new();
set.extend(iter);
set
}
}
impl<T: Ord> Extend<T> for BTreeSet<T> {
#[inline]
fn extend<Iter: Iterator<T>>(&mut self, mut iter: Iter) {
for elem in iter {
self.insert(elem);
}
}
}
impl<T: Ord> Default for BTreeSet<T> {
fn default() -> BTreeSet<T> {
BTreeSet::new()
}
}
#[unstable = "matches collection reform specification, waiting for dust to settle"]
impl<T: Ord + Clone> Sub<BTreeSet<T>,BTreeSet<T>> for BTreeSet<T> {
/// Returns the difference of `self` and `rhs` as a new `BTreeSet<T>`.
///
/// # Examples
///
/// ```
/// use std::collections::BTreeSet;
///
/// let a: BTreeSet<int> = vec![1,2,3].into_iter().collect();
/// let b: BTreeSet<int> = vec![3,4,5].into_iter().collect();
///
/// let result: BTreeSet<int> = a - b;
/// let result_vec: Vec<int> = result.into_iter().collect();
/// assert_eq!(result_vec, vec![1,2]);
/// ```
fn sub(&self, rhs: &BTreeSet<T>) -> BTreeSet<T> {
self.difference(rhs).cloned().collect()
}
}
#[unstable = "matches collection reform specification, waiting for dust to settle"]
impl<T: Ord + Clone> BitXor<BTreeSet<T>,BTreeSet<T>> for BTreeSet<T> {
/// Returns the symmetric difference of `self` and `rhs` as a new `BTreeSet<T>`.
///
/// # Examples
///
/// ```
/// use std::collections::BTreeSet;
///
/// let a: BTreeSet<int> = vec![1,2,3].into_iter().collect();
/// let b: BTreeSet<int> = vec![2,3,4].into_iter().collect();
///
/// let result: BTreeSet<int> = a ^ b;
/// let result_vec: Vec<int> = result.into_iter().collect();
/// assert_eq!(result_vec, vec![1,4]);
/// ```
fn bitxor(&self, rhs: &BTreeSet<T>) -> BTreeSet<T> {
self.symmetric_difference(rhs).cloned().collect()
}
}
#[unstable = "matches collection reform specification, waiting for dust to settle"]
impl<T: Ord + Clone> BitAnd<BTreeSet<T>,BTreeSet<T>> for BTreeSet<T> {
/// Returns the intersection of `self` and `rhs` as a new `BTreeSet<T>`.
///
/// # Examples
///
/// ```
/// use std::collections::BTreeSet;
///
/// let a: BTreeSet<int> = vec![1,2,3].into_iter().collect();
/// let b: BTreeSet<int> = vec![2,3,4].into_iter().collect();
///
/// let result: BTreeSet<int> = a & b;
/// let result_vec: Vec<int> = result.into_iter().collect();
/// assert_eq!(result_vec, vec![2,3]);
/// ```
fn bitand(&self, rhs: &BTreeSet<T>) -> BTreeSet<T> {
self.intersection(rhs).cloned().collect()
}
}
#[unstable = "matches collection reform specification, waiting for dust to settle"]
impl<T: Ord + Clone> BitOr<BTreeSet<T>,BTreeSet<T>> for BTreeSet<T> {
/// Returns the union of `self` and `rhs` as a new `BTreeSet<T>`.
///
/// # Examples
///
/// ```
/// use std::collections::BTreeSet;
///
/// let a: BTreeSet<int> = vec![1,2,3].into_iter().collect();
/// let b: BTreeSet<int> = vec![3,4,5].into_iter().collect();
///
/// let result: BTreeSet<int> = a | b;
/// let result_vec: Vec<int> = result.into_iter().collect();
/// assert_eq!(result_vec, vec![1,2,3,4,5]);
/// ```
fn bitor(&self, rhs: &BTreeSet<T>) -> BTreeSet<T> {
self.union(rhs).cloned().collect()
}
}
impl<T: Show> Show for BTreeSet<T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
try!(write!(f, "{{"));
for (i, x) in self.iter().enumerate() {
if i != 0 { try!(write!(f, ", ")); }
try!(write!(f, "{}", *x));
}
write!(f, "}}")
}
}
/// Compare `x` and `y`, but return `short` if x is None and `long` if y is None
fn cmp_opt<T: Ord>(x: Option<&T>, y: Option<&T>,
short: Ordering, long: Ordering) -> Ordering {
match (x, y) {
(None , _ ) => short,
(_ , None ) => long,
(Some(x1), Some(y1)) => x1.cmp(y1),
}
}
impl<'a, T: Ord> Iterator<&'a T> for DifferenceItems<'a, T> {
fn next(&mut self) -> Option<&'a T> {
loop {
match cmp_opt(self.a.peek(), self.b.peek(), Less, Less) {
Less => return self.a.next(),
Equal => { self.a.next(); self.b.next(); }
Greater => { self.b.next(); }
}
}
}
}
impl<'a, T: Ord> Iterator<&'a T> for SymDifferenceItems<'a, T> {
fn next(&mut self) -> Option<&'a T> {
loop {
match cmp_opt(self.a.peek(), self.b.peek(), Greater, Less) {
Less => return self.a.next(),
Equal => { self.a.next(); self.b.next(); }
Greater => return self.b.next(),
}
}
}
}
impl<'a, T: Ord> Iterator<&'a T> for IntersectionItems<'a, T> {
fn next(&mut self) -> Option<&'a T> {
loop {
let o_cmp = match (self.a.peek(), self.b.peek()) {
(None , _ ) => None,
(_ , None ) => None,
(Some(a1), Some(b1)) => Some(a1.cmp(b1)),
};
match o_cmp {
None => return None,
Some(Less) => { self.a.next(); }
Some(Equal) => { self.b.next(); return self.a.next() }
Some(Greater) => { self.b.next(); }
}
}
}
}
impl<'a, T: Ord> Iterator<&'a T> for UnionItems<'a, T> {
fn next(&mut self) -> Option<&'a T> {
loop {
match cmp_opt(self.a.peek(), self.b.peek(), Greater, Less) {
Less => return self.a.next(),
Equal => { self.b.next(); return self.a.next() }
Greater => return self.b.next(),
}
}
}
}
#[cfg(test)]
mod test {
use std::prelude::*;
use super::BTreeSet;
use std::hash;
#[test]
fn test_clone_eq() {
let mut m = BTreeSet::new();
m.insert(1i);
m.insert(2);
assert!(m.clone() == m);
}
#[test]
fn test_hash() {
let mut x = BTreeSet::new();
let mut y = BTreeSet::new();
x.insert(1i);
x.insert(2);
x.insert(3);
y.insert(3i);
y.insert(2);
y.insert(1);
assert!(hash::hash(&x) == hash::hash(&y));
}
fn check(a: &[int],
b: &[int],
expected: &[int],
f: |&BTreeSet<int>, &BTreeSet<int>, f: |&int| -> bool| -> bool) {
let mut set_a = BTreeSet::new();
let mut set_b = BTreeSet::new();
for x in a.iter() { assert!(set_a.insert(*x)) }
for y in b.iter() { assert!(set_b.insert(*y)) }
let mut i = 0;
f(&set_a, &set_b, |x| {
assert_eq!(*x, expected[i]);
i += 1;
true
});
assert_eq!(i, expected.len());
}
#[test]
fn test_intersection() {
fn check_intersection(a: &[int], b: &[int], expected: &[int]) {
check(a, b, expected, |x, y, f| x.intersection(y).all(f))
}
check_intersection(&[], &[], &[]);
check_intersection(&[1, 2, 3], &[], &[]);
check_intersection(&[], &[1, 2, 3], &[]);
check_intersection(&[2], &[1, 2, 3], &[2]);
check_intersection(&[1, 2, 3], &[2], &[2]);
check_intersection(&[11, 1, 3, 77, 103, 5, -5],
&[2, 11, 77, -9, -42, 5, 3],
&[3, 5, 11, 77]);
}
#[test]
fn test_difference() {
fn check_difference(a: &[int], b: &[int], expected: &[int]) {
check(a, b, expected, |x, y, f| x.difference(y).all(f))
}
check_difference(&[], &[], &[]);
check_difference(&[1, 12], &[], &[1, 12]);
check_difference(&[], &[1, 2, 3, 9], &[]);
check_difference(&[1, 3, 5, 9, 11],
&[3, 9],
&[1, 5, 11]);
check_difference(&[-5, 11, 22, 33, 40, 42],
&[-12, -5, 14, 23, 34, 38, 39, 50],
&[11, 22, 33, 40, 42]);
}
#[test]
fn test_symmetric_difference() {
fn check_symmetric_difference(a: &[int], b: &[int],
expected: &[int]) {
check(a, b, expected, |x, y, f| x.symmetric_difference(y).all(f))
}
check_symmetric_difference(&[], &[], &[]);
check_symmetric_difference(&[1, 2, 3], &[2], &[1, 3]);
check_symmetric_difference(&[2], &[1, 2, 3], &[1, 3]);
check_symmetric_difference(&[1, 3, 5, 9, 11],
&[-2, 3, 9, 14, 22],
&[-2, 1, 5, 11, 14, 22]);
}
#[test]
fn test_union() {
fn check_union(a: &[int], b: &[int],
expected: &[int]) {
check(a, b, expected, |x, y, f| x.union(y).all(f))
}
check_union(&[], &[], &[]);
check_union(&[1, 2, 3], &[2], &[1, 2, 3]);
check_union(&[2], &[1, 2, 3], &[1, 2, 3]);
check_union(&[1, 3, 5, 9, 11, 16, 19, 24],
&[-2, 1, 5, 9, 13, 19],
&[-2, 1, 3, 5, 9, 11, 13, 16, 19, 24]);
}
#[test]
fn test_zip() {
let mut x = BTreeSet::new();
x.insert(5u);
x.insert(12u);
x.insert(11u);
let mut y = BTreeSet::new();
y.insert("foo");
y.insert("bar");
let x = x;
let y = y;
let mut z = x.iter().zip(y.iter());
// FIXME: #5801: this needs a type hint to compile...
let result: Option<(&uint, & &'static str)> = z.next();
assert_eq!(result.unwrap(), (&5u, &("bar")));
let result: Option<(&uint, & &'static str)> = z.next();
assert_eq!(result.unwrap(), (&11u, &("foo")));
let result: Option<(&uint, & &'static str)> = z.next();
assert!(result.is_none());
}
#[test]
fn test_from_iter() {
let xs = [1i, 2, 3, 4, 5, 6, 7, 8, 9];
let set: BTreeSet<int> = xs.iter().map(|&x| x).collect();
for x in xs.iter() {
assert!(set.contains(x));
}
}
#[test]
fn test_show() {
let mut set: BTreeSet<int> = BTreeSet::new();
let empty: BTreeSet<int> = BTreeSet::new();
set.insert(1);
set.insert(2);
let set_str = format!("{}", set);
assert!(set_str == "{1, 2}".to_string());
assert_eq!(format!("{}", empty), "{}".to_string());
}
}