1 // Copyright 2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 // This is pretty much entirely stolen from TreeSet, since BTreeMap has an identical interface
16 use core::borrow::BorrowFrom;
17 use core::cmp::Ordering::{self, Less, Greater, Equal};
18 use core::default::Default;
21 use core::iter::{Peekable, Map, FromIterator};
22 use core::ops::{BitOr, BitAnd, BitXor, Sub};
24 use btree_map::{BTreeMap, Keys};
27 // FIXME(conventions): implement bounded iterators
29 /// A set based on a B-Tree.
31 /// See BTreeMap's documentation for a detailed discussion of this collection's performance
32 /// benefits and drawbacks.
33 #[derive(Clone, Hash, PartialEq, Eq, Ord, PartialOrd)]
35 pub struct BTreeSet<T>{
39 /// An iterator over a BTreeSet's items.
41 pub struct Iter<'a, T: 'a> {
45 /// An owning iterator over a BTreeSet's items.
47 pub struct IntoIter<T> {
48 iter: Map<(T, ()), T, ::btree_map::IntoIter<T, ()>, fn((T, ())) -> T>
51 /// An iterator over a sub-range of BTreeSet's items.
52 pub struct Range<'a, T: 'a> {
53 iter: Map<(&'a T, &'a ()), &'a T, ::btree_map::Range<'a, T, ()>, fn((&'a T, &'a ())) -> &'a T>
56 /// A lazy iterator producing elements in the set difference (in-order).
58 pub struct Difference<'a, T:'a> {
59 a: Peekable<&'a T, Iter<'a, T>>,
60 b: Peekable<&'a T, Iter<'a, T>>,
63 /// A lazy iterator producing elements in the set symmetric difference (in-order).
65 pub struct SymmetricDifference<'a, T:'a> {
66 a: Peekable<&'a T, Iter<'a, T>>,
67 b: Peekable<&'a T, Iter<'a, T>>,
70 /// A lazy iterator producing elements in the set intersection (in-order).
72 pub struct Intersection<'a, T:'a> {
73 a: Peekable<&'a T, Iter<'a, T>>,
74 b: Peekable<&'a T, Iter<'a, T>>,
77 /// A lazy iterator producing elements in the set union (in-order).
79 pub struct Union<'a, T:'a> {
80 a: Peekable<&'a T, Iter<'a, T>>,
81 b: Peekable<&'a T, Iter<'a, T>>,
84 impl<T: Ord> BTreeSet<T> {
85 /// Makes a new BTreeSet with a reasonable choice of B.
90 /// use std::collections::BTreeSet;
92 /// let mut set: BTreeSet<int> = BTreeSet::new();
95 pub fn new() -> BTreeSet<T> {
96 BTreeSet { map: BTreeMap::new() }
99 /// Makes a new BTreeSet with the given B.
101 /// B cannot be less than 2.
102 #[unstable = "probably want this to be on the type, eventually"]
103 pub fn with_b(b: uint) -> BTreeSet<T> {
104 BTreeSet { map: BTreeMap::with_b(b) }
108 impl<T> BTreeSet<T> {
109 /// Gets an iterator over the BTreeSet's contents.
114 /// use std::collections::BTreeSet;
116 /// let set: BTreeSet<uint> = [1u, 2, 3, 4].iter().map(|&x| x).collect();
118 /// for x in set.iter() {
119 /// println!("{}", x);
122 /// let v: Vec<uint> = set.iter().map(|&x| x).collect();
123 /// assert_eq!(v, vec![1u,2,3,4]);
126 pub fn iter(&self) -> Iter<T> {
127 Iter { iter: self.map.keys() }
130 /// Gets an iterator for moving out the BtreeSet's contents.
135 /// use std::collections::BTreeSet;
137 /// let set: BTreeSet<uint> = [1u, 2, 3, 4].iter().map(|&x| x).collect();
139 /// let v: Vec<uint> = set.into_iter().collect();
140 /// assert_eq!(v, vec![1u,2,3,4]);
143 pub fn into_iter(self) -> IntoIter<T> {
144 fn first<A, B>((a, _): (A, B)) -> A { a }
145 let first: fn((T, ())) -> T = first; // coerce to fn pointer
147 IntoIter { iter: self.map.into_iter().map(first) }
151 impl<T: Ord> BTreeSet<T> {
152 /// Constructs a double-ended iterator over a sub-range of elements in the set, starting
153 /// at min, and ending at max. If min is `Unbounded`, then it will be treated as "negative
154 /// infinity", and if max is `Unbounded`, then it will be treated as "positive infinity".
155 /// Thus range(Unbounded, Unbounded) will yield the whole collection.
160 /// use std::collections::BTreeSet;
161 /// use std::collections::Bound::{Included, Unbounded};
163 /// let mut set = BTreeSet::new();
167 /// for &elem in set.range(Included(&4), Included(&8)) {
168 /// println!("{}", elem);
170 /// assert_eq!(Some(&5u), set.range(Included(&4), Unbounded).next());
172 #[unstable = "matches collection reform specification, waiting for dust to settle"]
173 pub fn range<'a>(&'a self, min: Bound<&T>, max: Bound<&T>) -> Range<'a, T> {
174 fn first<A, B>((a, _): (A, B)) -> A { a }
175 let first: fn((&'a T, &'a ())) -> &'a T = first; // coerce to fn pointer
177 Range { iter: self.map.range(min, max).map(first) }
181 impl<T: Ord> BTreeSet<T> {
182 /// Visits the values representing the difference, in ascending order.
187 /// use std::collections::BTreeSet;
189 /// let mut a = BTreeSet::new();
193 /// let mut b = BTreeSet::new();
197 /// let diff: Vec<uint> = a.difference(&b).cloned().collect();
198 /// assert_eq!(diff, vec![1u]);
201 pub fn difference<'a>(&'a self, other: &'a BTreeSet<T>) -> Difference<'a, T> {
202 Difference{a: self.iter().peekable(), b: other.iter().peekable()}
205 /// Visits the values representing the symmetric difference, in ascending order.
210 /// use std::collections::BTreeSet;
212 /// let mut a = BTreeSet::new();
216 /// let mut b = BTreeSet::new();
220 /// let sym_diff: Vec<uint> = a.symmetric_difference(&b).cloned().collect();
221 /// assert_eq!(sym_diff, vec![1u,3]);
224 pub fn symmetric_difference<'a>(&'a self, other: &'a BTreeSet<T>)
225 -> SymmetricDifference<'a, T> {
226 SymmetricDifference{a: self.iter().peekable(), b: other.iter().peekable()}
229 /// Visits the values representing the intersection, in ascending order.
234 /// use std::collections::BTreeSet;
236 /// let mut a = BTreeSet::new();
240 /// let mut b = BTreeSet::new();
244 /// let intersection: Vec<uint> = a.intersection(&b).cloned().collect();
245 /// assert_eq!(intersection, vec![2u]);
248 pub fn intersection<'a>(&'a self, other: &'a BTreeSet<T>)
249 -> Intersection<'a, T> {
250 Intersection{a: self.iter().peekable(), b: other.iter().peekable()}
253 /// Visits the values representing the union, in ascending order.
258 /// use std::collections::BTreeSet;
260 /// let mut a = BTreeSet::new();
263 /// let mut b = BTreeSet::new();
266 /// let union: Vec<uint> = a.union(&b).cloned().collect();
267 /// assert_eq!(union, vec![1u,2]);
270 pub fn union<'a>(&'a self, other: &'a BTreeSet<T>) -> Union<'a, T> {
271 Union{a: self.iter().peekable(), b: other.iter().peekable()}
274 /// Return the number of elements in the set
279 /// use std::collections::BTreeSet;
281 /// let mut v = BTreeSet::new();
282 /// assert_eq!(v.len(), 0);
284 /// assert_eq!(v.len(), 1);
287 pub fn len(&self) -> uint { self.map.len() }
289 /// Returns true if the set contains no elements
294 /// use std::collections::BTreeSet;
296 /// let mut v = BTreeSet::new();
297 /// assert!(v.is_empty());
299 /// assert!(!v.is_empty());
302 pub fn is_empty(&self) -> bool { self.len() == 0 }
304 /// Clears the set, removing all values.
309 /// use std::collections::BTreeSet;
311 /// let mut v = BTreeSet::new();
314 /// assert!(v.is_empty());
317 pub fn clear(&mut self) {
321 /// Returns `true` if the set contains a value.
323 /// The value may be any borrowed form of the set's value type,
324 /// but the ordering on the borrowed form *must* match the
325 /// ordering on the value type.
330 /// use std::collections::BTreeSet;
332 /// let set: BTreeSet<int> = [1i, 2, 3].iter().map(|&x| x).collect();
333 /// assert_eq!(set.contains(&1), true);
334 /// assert_eq!(set.contains(&4), false);
337 pub fn contains<Q: ?Sized>(&self, value: &Q) -> bool where Q: BorrowFrom<T> + Ord {
338 self.map.contains_key(value)
341 /// Returns `true` if the set has no elements in common with `other`.
342 /// This is equivalent to checking for an empty intersection.
347 /// use std::collections::BTreeSet;
349 /// let a: BTreeSet<int> = [1i, 2, 3].iter().map(|&x| x).collect();
350 /// let mut b: BTreeSet<int> = BTreeSet::new();
352 /// assert_eq!(a.is_disjoint(&b), true);
354 /// assert_eq!(a.is_disjoint(&b), true);
356 /// assert_eq!(a.is_disjoint(&b), false);
359 pub fn is_disjoint(&self, other: &BTreeSet<T>) -> bool {
360 self.intersection(other).next().is_none()
363 /// Returns `true` if the set is a subset of another.
368 /// use std::collections::BTreeSet;
370 /// let sup: BTreeSet<int> = [1i, 2, 3].iter().map(|&x| x).collect();
371 /// let mut set: BTreeSet<int> = BTreeSet::new();
373 /// assert_eq!(set.is_subset(&sup), true);
375 /// assert_eq!(set.is_subset(&sup), true);
377 /// assert_eq!(set.is_subset(&sup), false);
380 pub fn is_subset(&self, other: &BTreeSet<T>) -> bool {
381 // Stolen from TreeMap
382 let mut x = self.iter();
383 let mut y = other.iter();
384 let mut a = x.next();
385 let mut b = y.next();
396 Greater => return false,
397 Equal => a = x.next(),
405 /// Returns `true` if the set is a superset of another.
410 /// use std::collections::BTreeSet;
412 /// let sub: BTreeSet<int> = [1i, 2].iter().map(|&x| x).collect();
413 /// let mut set: BTreeSet<int> = BTreeSet::new();
415 /// assert_eq!(set.is_superset(&sub), false);
419 /// assert_eq!(set.is_superset(&sub), false);
422 /// assert_eq!(set.is_superset(&sub), true);
425 pub fn is_superset(&self, other: &BTreeSet<T>) -> bool {
426 other.is_subset(self)
429 /// Adds a value to the set. Returns `true` if the value was not already
430 /// present in the set.
435 /// use std::collections::BTreeSet;
437 /// let mut set = BTreeSet::new();
439 /// assert_eq!(set.insert(2i), true);
440 /// assert_eq!(set.insert(2i), false);
441 /// assert_eq!(set.len(), 1);
444 pub fn insert(&mut self, value: T) -> bool {
445 self.map.insert(value, ()).is_none()
448 /// Removes a value from the set. Returns `true` if the value was
449 /// present in the set.
451 /// The value may be any borrowed form of the set's value type,
452 /// but the ordering on the borrowed form *must* match the
453 /// ordering on the value type.
458 /// use std::collections::BTreeSet;
460 /// let mut set = BTreeSet::new();
463 /// assert_eq!(set.remove(&2), true);
464 /// assert_eq!(set.remove(&2), false);
467 pub fn remove<Q: ?Sized>(&mut self, value: &Q) -> bool where Q: BorrowFrom<T> + Ord {
468 self.map.remove(value).is_some()
473 impl<T: Ord> FromIterator<T> for BTreeSet<T> {
474 fn from_iter<Iter: Iterator<Item=T>>(iter: Iter) -> BTreeSet<T> {
475 let mut set = BTreeSet::new();
482 impl<T: Ord> Extend<T> for BTreeSet<T> {
484 fn extend<Iter: Iterator<Item=T>>(&mut self, mut iter: Iter) {
492 impl<T: Ord> Default for BTreeSet<T> {
494 fn default() -> BTreeSet<T> {
500 impl<'a, 'b, T: Ord + Clone> Sub<&'b BTreeSet<T>> for &'a BTreeSet<T> {
501 type Output = BTreeSet<T>;
503 /// Returns the difference of `self` and `rhs` as a new `BTreeSet<T>`.
508 /// use std::collections::BTreeSet;
510 /// let a: BTreeSet<int> = vec![1, 2, 3].into_iter().collect();
511 /// let b: BTreeSet<int> = vec![3, 4, 5].into_iter().collect();
513 /// let result: BTreeSet<int> = &a - &b;
514 /// let result_vec: Vec<int> = result.into_iter().collect();
515 /// assert_eq!(result_vec, vec![1, 2]);
517 fn sub(self, rhs: &BTreeSet<T>) -> BTreeSet<T> {
518 self.difference(rhs).cloned().collect()
523 impl<'a, 'b, T: Ord + Clone> BitXor<&'b BTreeSet<T>> for &'a BTreeSet<T> {
524 type Output = BTreeSet<T>;
526 /// Returns the symmetric difference of `self` and `rhs` as a new `BTreeSet<T>`.
531 /// use std::collections::BTreeSet;
533 /// let a: BTreeSet<int> = vec![1, 2, 3].into_iter().collect();
534 /// let b: BTreeSet<int> = vec![2, 3, 4].into_iter().collect();
536 /// let result: BTreeSet<int> = &a ^ &b;
537 /// let result_vec: Vec<int> = result.into_iter().collect();
538 /// assert_eq!(result_vec, vec![1, 4]);
540 fn bitxor(self, rhs: &BTreeSet<T>) -> BTreeSet<T> {
541 self.symmetric_difference(rhs).cloned().collect()
546 impl<'a, 'b, T: Ord + Clone> BitAnd<&'b BTreeSet<T>> for &'a BTreeSet<T> {
547 type Output = BTreeSet<T>;
549 /// Returns the intersection of `self` and `rhs` as a new `BTreeSet<T>`.
554 /// use std::collections::BTreeSet;
556 /// let a: BTreeSet<int> = vec![1, 2, 3].into_iter().collect();
557 /// let b: BTreeSet<int> = vec![2, 3, 4].into_iter().collect();
559 /// let result: BTreeSet<int> = &a & &b;
560 /// let result_vec: Vec<int> = result.into_iter().collect();
561 /// assert_eq!(result_vec, vec![2, 3]);
563 fn bitand(self, rhs: &BTreeSet<T>) -> BTreeSet<T> {
564 self.intersection(rhs).cloned().collect()
569 impl<'a, 'b, T: Ord + Clone> BitOr<&'b BTreeSet<T>> for &'a BTreeSet<T> {
570 type Output = BTreeSet<T>;
572 /// Returns the union of `self` and `rhs` as a new `BTreeSet<T>`.
577 /// use std::collections::BTreeSet;
579 /// let a: BTreeSet<int> = vec![1, 2, 3].into_iter().collect();
580 /// let b: BTreeSet<int> = vec![3, 4, 5].into_iter().collect();
582 /// let result: BTreeSet<int> = &a | &b;
583 /// let result_vec: Vec<int> = result.into_iter().collect();
584 /// assert_eq!(result_vec, vec![1, 2, 3, 4, 5]);
586 fn bitor(self, rhs: &BTreeSet<T>) -> BTreeSet<T> {
587 self.union(rhs).cloned().collect()
592 impl<T: Debug> Debug for BTreeSet<T> {
593 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
594 try!(write!(f, "BTreeSet {{"));
596 for (i, x) in self.iter().enumerate() {
597 if i != 0 { try!(write!(f, ", ")); }
598 try!(write!(f, "{:?}", *x));
606 impl<'a, T> Iterator for Iter<'a, T> {
609 fn next(&mut self) -> Option<&'a T> { self.iter.next() }
610 fn size_hint(&self) -> (uint, Option<uint>) { self.iter.size_hint() }
613 impl<'a, T> DoubleEndedIterator for Iter<'a, T> {
614 fn next_back(&mut self) -> Option<&'a T> { self.iter.next_back() }
617 impl<'a, T> ExactSizeIterator for Iter<'a, T> {}
621 impl<T> Iterator for IntoIter<T> {
624 fn next(&mut self) -> Option<T> { self.iter.next() }
625 fn size_hint(&self) -> (uint, Option<uint>) { self.iter.size_hint() }
628 impl<T> DoubleEndedIterator for IntoIter<T> {
629 fn next_back(&mut self) -> Option<T> { self.iter.next_back() }
632 impl<T> ExactSizeIterator for IntoIter<T> {}
635 impl<'a, T> Iterator for Range<'a, T> {
638 fn next(&mut self) -> Option<&'a T> { self.iter.next() }
640 impl<'a, T> DoubleEndedIterator for Range<'a, T> {
641 fn next_back(&mut self) -> Option<&'a T> { self.iter.next_back() }
644 /// Compare `x` and `y`, but return `short` if x is None and `long` if y is None
645 fn cmp_opt<T: Ord>(x: Option<&T>, y: Option<&T>,
646 short: Ordering, long: Ordering) -> Ordering {
648 (None , _ ) => short,
650 (Some(x1), Some(y1)) => x1.cmp(y1),
655 impl<'a, T: Ord> Iterator for Difference<'a, T> {
658 fn next(&mut self) -> Option<&'a T> {
660 match cmp_opt(self.a.peek(), self.b.peek(), Less, Less) {
661 Less => return self.a.next(),
662 Equal => { self.a.next(); self.b.next(); }
663 Greater => { self.b.next(); }
670 impl<'a, T: Ord> Iterator for SymmetricDifference<'a, T> {
673 fn next(&mut self) -> Option<&'a T> {
675 match cmp_opt(self.a.peek(), self.b.peek(), Greater, Less) {
676 Less => return self.a.next(),
677 Equal => { self.a.next(); self.b.next(); }
678 Greater => return self.b.next(),
685 impl<'a, T: Ord> Iterator for Intersection<'a, T> {
688 fn next(&mut self) -> Option<&'a T> {
690 let o_cmp = match (self.a.peek(), self.b.peek()) {
693 (Some(a1), Some(b1)) => Some(a1.cmp(b1)),
697 Some(Less) => { self.a.next(); }
698 Some(Equal) => { self.b.next(); return self.a.next() }
699 Some(Greater) => { self.b.next(); }
706 impl<'a, T: Ord> Iterator for Union<'a, T> {
709 fn next(&mut self) -> Option<&'a T> {
711 match cmp_opt(self.a.peek(), self.b.peek(), Greater, Less) {
712 Less => return self.a.next(),
713 Equal => { self.b.next(); return self.a.next() }
714 Greater => return self.b.next(),
726 use std::hash::{self, SipHasher};
730 let mut m = BTreeSet::new();
735 assert!(m.clone() == m);
740 let mut x = BTreeSet::new();
741 let mut y = BTreeSet::new();
751 assert!(hash::hash::<_, SipHasher>(&x) == hash::hash::<_, SipHasher>(&y));
754 struct Counter<'a, 'b> {
759 impl<'a, 'b, 'c> FnMut(&'c int) -> bool for Counter<'a, 'b> {
760 extern "rust-call" fn call_mut(&mut self, (&x,): (&'c int,)) -> bool {
761 assert_eq!(x, self.expected[*self.i]);
767 fn check<F>(a: &[int], b: &[int], expected: &[int], f: F) where
768 // FIXME Replace Counter with `Box<FnMut(_) -> _>`
769 F: FnOnce(&BTreeSet<int>, &BTreeSet<int>, Counter) -> bool,
771 let mut set_a = BTreeSet::new();
772 let mut set_b = BTreeSet::new();
774 for x in a.iter() { assert!(set_a.insert(*x)) }
775 for y in b.iter() { assert!(set_b.insert(*y)) }
778 f(&set_a, &set_b, Counter { i: &mut i, expected: expected });
779 assert_eq!(i, expected.len());
783 fn test_intersection() {
784 fn check_intersection(a: &[int], b: &[int], expected: &[int]) {
785 check(a, b, expected, |x, y, f| x.intersection(y).all(f))
788 check_intersection(&[], &[], &[]);
789 check_intersection(&[1, 2, 3], &[], &[]);
790 check_intersection(&[], &[1, 2, 3], &[]);
791 check_intersection(&[2], &[1, 2, 3], &[2]);
792 check_intersection(&[1, 2, 3], &[2], &[2]);
793 check_intersection(&[11, 1, 3, 77, 103, 5, -5],
794 &[2, 11, 77, -9, -42, 5, 3],
799 fn test_difference() {
800 fn check_difference(a: &[int], b: &[int], expected: &[int]) {
801 check(a, b, expected, |x, y, f| x.difference(y).all(f))
804 check_difference(&[], &[], &[]);
805 check_difference(&[1, 12], &[], &[1, 12]);
806 check_difference(&[], &[1, 2, 3, 9], &[]);
807 check_difference(&[1, 3, 5, 9, 11],
810 check_difference(&[-5, 11, 22, 33, 40, 42],
811 &[-12, -5, 14, 23, 34, 38, 39, 50],
812 &[11, 22, 33, 40, 42]);
816 fn test_symmetric_difference() {
817 fn check_symmetric_difference(a: &[int], b: &[int],
819 check(a, b, expected, |x, y, f| x.symmetric_difference(y).all(f))
822 check_symmetric_difference(&[], &[], &[]);
823 check_symmetric_difference(&[1, 2, 3], &[2], &[1, 3]);
824 check_symmetric_difference(&[2], &[1, 2, 3], &[1, 3]);
825 check_symmetric_difference(&[1, 3, 5, 9, 11],
827 &[-2, 1, 5, 11, 14, 22]);
832 fn check_union(a: &[int], b: &[int],
834 check(a, b, expected, |x, y, f| x.union(y).all(f))
837 check_union(&[], &[], &[]);
838 check_union(&[1, 2, 3], &[2], &[1, 2, 3]);
839 check_union(&[2], &[1, 2, 3], &[1, 2, 3]);
840 check_union(&[1, 3, 5, 9, 11, 16, 19, 24],
841 &[-2, 1, 5, 9, 13, 19],
842 &[-2, 1, 3, 5, 9, 11, 13, 16, 19, 24]);
847 let mut x = BTreeSet::new();
852 let mut y = BTreeSet::new();
858 let mut z = x.iter().zip(y.iter());
860 // FIXME: #5801: this needs a type hint to compile...
861 let result: Option<(&uint, & &'static str)> = z.next();
862 assert_eq!(result.unwrap(), (&5u, &("bar")));
864 let result: Option<(&uint, & &'static str)> = z.next();
865 assert_eq!(result.unwrap(), (&11u, &("foo")));
867 let result: Option<(&uint, & &'static str)> = z.next();
868 assert!(result.is_none());
872 fn test_from_iter() {
873 let xs = [1i, 2, 3, 4, 5, 6, 7, 8, 9];
875 let set: BTreeSet<int> = xs.iter().map(|&x| x).collect();
878 assert!(set.contains(x));
884 let mut set: BTreeSet<int> = BTreeSet::new();
885 let empty: BTreeSet<int> = BTreeSet::new();
890 let set_str = format!("{:?}", set);
892 assert_eq!(set_str, "BTreeSet {1, 2}");
893 assert_eq!(format!("{:?}", empty), "BTreeSet {}");