1 // Copyright 2013 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 //! An ordered map and set implemented as self-balancing binary search
12 //! trees. The only requirement for the types is that the key implements
18 //! use std::collections::TreeSet;
20 //! let mut tree_set = TreeSet::new();
22 //! tree_set.insert(2i);
23 //! tree_set.insert(1i);
24 //! tree_set.insert(3i);
26 //! for i in tree_set.iter() {
27 //! println!("{}", i) // prints 1, then 2, then 3
33 use alloc::boxed::Box;
34 use core::default::Default;
37 use core::iter::Peekable;
39 use core::mem::{replace, swap};
41 use std::hash::{Writer, Hash};
43 use {Collection, Mutable, Set, MutableSet, MutableMap, Map};
46 // This is implemented as an AA tree, which is a simplified variation of
47 // a red-black tree where red (horizontal) nodes can only be added
48 // as a right child. The time complexity is the same, and re-balancing
49 // operations are more frequent but also cheaper.
51 // Future improvements:
53 // range search - O(log n) retrieval of an iterator from some key
55 // (possibly) implement the overloads Python does for sets:
58 // * symmetric difference: ^
60 // These would be convenient since the methods work like `each`
64 pub struct TreeMap<K, V> {
65 root: Option<Box<TreeNode<K, V>>>,
69 impl<K: PartialEq + Ord, V: PartialEq> PartialEq for TreeMap<K, V> {
70 fn eq(&self, other: &TreeMap<K, V>) -> bool {
71 self.len() == other.len() &&
72 self.iter().zip(other.iter()).all(|(a, b)| a == b)
76 impl<K: Ord, V: PartialOrd> PartialOrd for TreeMap<K, V> {
78 fn partial_cmp(&self, other: &TreeMap<K, V>) -> Option<Ordering> {
79 iter::order::partial_cmp(self.iter(), other.iter())
83 impl<K: Ord + Show, V: Show> Show for TreeMap<K, V> {
84 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
85 try!(write!(f, "{{"));
87 for (i, (k, v)) in self.iter().enumerate() {
88 if i != 0 { try!(write!(f, ", ")); }
89 try!(write!(f, "{}: {}", *k, *v));
96 impl<K: Ord, V> Collection for TreeMap<K, V> {
97 fn len(&self) -> uint { self.length }
100 impl<K: Ord, V> Mutable for TreeMap<K, V> {
101 fn clear(&mut self) {
107 impl<K: Ord, V> Map<K, V> for TreeMap<K, V> {
108 // See comments on tree_find_with
110 fn find<'a>(&'a self, key: &K) -> Option<&'a V> {
111 tree_find_with(&self.root, |k2| key.cmp(k2))
115 impl<K: Ord, V> MutableMap<K, V> for TreeMap<K, V> {
116 // See comments on def_tree_find_mut_with
118 fn find_mut<'a>(&'a mut self, key: &K) -> Option<&'a mut V> {
119 tree_find_mut_with(&mut self.root, |x| key.cmp(x))
122 fn swap(&mut self, key: K, value: V) -> Option<V> {
123 let ret = insert(&mut self.root, key, value);
124 if ret.is_none() { self.length += 1 }
128 fn pop(&mut self, key: &K) -> Option<V> {
129 let ret = remove(&mut self.root, key);
130 if ret.is_some() { self.length -= 1 }
135 impl<K: Ord, V> Default for TreeMap<K,V> {
137 fn default() -> TreeMap<K, V> { TreeMap::new() }
140 impl<K: Ord, V> TreeMap<K, V> {
141 /// Create an empty TreeMap
142 pub fn new() -> TreeMap<K, V> { TreeMap{root: None, length: 0} }
144 /// Get a lazy iterator over the key-value pairs in the map.
145 /// Requires that it be frozen (immutable).
146 pub fn iter<'a>(&'a self) -> Entries<'a, K, V> {
149 node: deref(&self.root),
150 remaining_min: self.length,
151 remaining_max: self.length
155 /// Get a lazy reverse iterator over the key-value pairs in the map.
156 /// Requires that it be frozen (immutable).
157 pub fn rev_iter<'a>(&'a self) -> RevEntries<'a, K, V> {
158 RevEntries{iter: self.iter()}
161 /// Get a lazy forward iterator over the key-value pairs in the
162 /// map, with the values being mutable.
163 pub fn mut_iter<'a>(&'a mut self) -> MutEntries<'a, K, V> {
166 node: mut_deref(&mut self.root),
167 remaining_min: self.length,
168 remaining_max: self.length
171 /// Get a lazy reverse iterator over the key-value pairs in the
172 /// map, with the values being mutable.
173 pub fn mut_rev_iter<'a>(&'a mut self) -> RevMutEntries<'a, K, V> {
174 RevMutEntries{iter: self.mut_iter()}
178 /// Get a lazy iterator that consumes the treemap.
179 pub fn move_iter(self) -> MoveEntries<K, V> {
180 let TreeMap { root: root, length: length } = self;
181 let stk = match root {
183 Some(box tn) => vec!(tn)
192 impl<K, V> TreeMap<K, V> {
193 /// Return the value for which `f(key)` returns `Equal`. `f` is invoked
194 /// with current key and guides tree navigation. That means `f` should
195 /// be aware of natural ordering of the tree.
200 /// use collections::treemap::TreeMap;
202 /// fn get_headers() -> TreeMap<String, String> {
203 /// let mut result = TreeMap::new();
204 /// result.insert("Content-Type".to_string(), "application/xml".to_string());
205 /// result.insert("User-Agent".to_string(), "Curl-Rust/0.1".to_string());
209 /// let headers = get_headers();
210 /// let ua_key = "User-Agent";
211 /// let ua = headers.find_with(|k| {
212 /// ua_key.cmp(&k.as_slice())
215 /// assert_eq!((*ua.unwrap()).as_slice(), "Curl-Rust/0.1");
218 pub fn find_with<'a>(&'a self, f:|&K| -> Ordering) -> Option<&'a V> {
219 tree_find_with(&self.root, f)
222 /// Return the value for which `f(key)` returns `Equal`. `f` is invoked
223 /// with current key and guides tree navigation. That means `f` should
224 /// be aware of natural ordering of the tree.
228 /// let mut t = collections::treemap::TreeMap::new();
229 /// t.insert("Content-Type", "application/xml");
230 /// t.insert("User-Agent", "Curl-Rust/0.1");
232 /// let new_ua = "Safari/156.0";
233 /// match t.find_mut_with(|k| "User-Agent".cmp(k)) {
234 /// Some(x) => *x = new_ua,
238 /// assert_eq!(t.find(&"User-Agent"), Some(&new_ua));
241 pub fn find_mut_with<'a>(&'a mut self, f:|&K| -> Ordering) -> Option<&'a mut V> {
242 tree_find_mut_with(&mut self.root, f)
248 macro_rules! bound_setup {
249 // initialiser of the iterator to manipulate
250 ($iter:expr, $k:expr,
251 // whether we are looking for the lower or upper bound.
252 $is_lower_bound:expr) => {
254 let mut iter = $iter;
256 if !iter.node.is_null() {
257 let node_k = unsafe {&(*iter.node).key};
258 match $k.cmp(node_k) {
259 Less => iter.traverse_left(),
260 Greater => iter.traverse_right(),
263 iter.traverse_complete();
266 iter.traverse_right()
271 iter.traverse_complete();
280 impl<K: Ord, V> TreeMap<K, V> {
281 /// Get a lazy iterator that should be initialized using
282 /// `traverse_left`/`traverse_right`/`traverse_complete`.
283 fn iter_for_traversal<'a>(&'a self) -> Entries<'a, K, V> {
286 node: deref(&self.root),
288 remaining_max: self.length
292 /// Return a lazy iterator to the first key-value pair whose key is not less than `k`
293 /// If all keys in map are less than `k` an empty iterator is returned.
294 pub fn lower_bound<'a>(&'a self, k: &K) -> Entries<'a, K, V> {
295 bound_setup!(self.iter_for_traversal(), k, true)
298 /// Return a lazy iterator to the first key-value pair whose key is greater than `k`
299 /// If all keys in map are not greater than `k` an empty iterator is returned.
300 pub fn upper_bound<'a>(&'a self, k: &K) -> Entries<'a, K, V> {
301 bound_setup!(self.iter_for_traversal(), k, false)
304 /// Get a lazy iterator that should be initialized using
305 /// `traverse_left`/`traverse_right`/`traverse_complete`.
306 fn mut_iter_for_traversal<'a>(&'a mut self) -> MutEntries<'a, K, V> {
309 node: mut_deref(&mut self.root),
311 remaining_max: self.length
315 /// Return a lazy value iterator to the first key-value pair (with
316 /// the value being mutable) whose key is not less than `k`.
318 /// If all keys in map are less than `k` an empty iterator is
320 pub fn mut_lower_bound<'a>(&'a mut self, k: &K) -> MutEntries<'a, K, V> {
321 bound_setup!(self.mut_iter_for_traversal(), k, true)
324 /// Return a lazy iterator to the first key-value pair (with the
325 /// value being mutable) whose key is greater than `k`.
327 /// If all keys in map are not greater than `k` an empty iterator
329 pub fn mut_upper_bound<'a>(&'a mut self, k: &K) -> MutEntries<'a, K, V> {
330 bound_setup!(self.mut_iter_for_traversal(), k, false)
334 /// Lazy forward iterator over a map
335 pub struct Entries<'a, K, V> {
336 stack: Vec<&'a TreeNode<K, V>>,
337 // See the comment on MutEntries; this is just to allow
338 // code-sharing (for this immutable-values iterator it *could* very
339 // well be Option<&'a TreeNode<K,V>>).
340 node: *const TreeNode<K, V>,
345 /// Lazy backward iterator over a map
346 pub struct RevEntries<'a, K, V> {
347 iter: Entries<'a, K, V>,
350 /// Lazy forward iterator over a map that allows for the mutation of
352 pub struct MutEntries<'a, K, V> {
353 stack: Vec<&'a mut TreeNode<K, V>>,
354 // Unfortunately, we require some unsafe-ness to get around the
355 // fact that we would be storing a reference *into* one of the
356 // nodes in the stack.
358 // As far as the compiler knows, this would let us invalidate the
359 // reference by assigning a new value to this node's position in
360 // its parent, which would cause this current one to be
361 // deallocated so this reference would be invalid. (i.e. the
362 // compilers complaints are 100% correct.)
364 // However, as far as you humans reading this code know (or are
365 // about to know, if you haven't read far enough down yet), we are
366 // only reading from the TreeNode.{left,right} fields. the only
367 // thing that is ever mutated is the .value field (although any
368 // actual mutation that happens is done externally, by the
369 // iterator consumer). So, don't be so concerned, rustc, we've got
372 // (This field can legitimately be null.)
373 node: *mut TreeNode<K, V>,
378 /// Lazy backward iterator over a map
379 pub struct RevMutEntries<'a, K, V> {
380 iter: MutEntries<'a, K, V>,
384 // FIXME #5846 we want to be able to choose between &x and &mut x
385 // (with many different `x`) below, so we need to optionally pass mut
386 // as a tt, but the only thing we can do with a `tt` is pass them to
387 // other macros, so this takes the `& <mutability> <operand>` token
388 // sequence and forces their evaluation as an expression.
389 macro_rules! addr { ($e:expr) => { $e }}
390 // putting an optional mut into type signatures
391 macro_rules! item { ($i:item) => { $i }}
393 macro_rules! define_iterator {
397 // the function to go from &m Option<Box<TreeNode>> to *m TreeNode
398 deref = $deref:ident,
400 // see comment on `addr!`, this is just an optional `mut`, but
401 // there's no support for 0-or-1 repeats.
402 addr_mut = $($addr_mut:tt)*
404 // private methods on the forward iterator (item!() for the
405 // addr_mut in the next_ return value)
406 item!(impl<'a, K, V> $name<'a, K, V> {
408 fn next_(&mut self, forward: bool) -> Option<(&'a K, &'a $($addr_mut)* V)> {
409 while !self.stack.is_empty() || !self.node.is_null() {
410 if !self.node.is_null() {
411 let node = unsafe {addr!(& $($addr_mut)* *self.node)};
413 let next_node = if forward {
414 addr!(& $($addr_mut)* node.left)
416 addr!(& $($addr_mut)* node.right)
418 self.node = $deref(next_node);
420 self.stack.push(node);
422 let node = self.stack.pop().unwrap();
423 let next_node = if forward {
424 addr!(& $($addr_mut)* node.right)
426 addr!(& $($addr_mut)* node.left)
428 self.node = $deref(next_node);
429 self.remaining_max -= 1;
430 if self.remaining_min > 0 {
431 self.remaining_min -= 1;
433 return Some((&node.key, addr!(& $($addr_mut)* node.value)));
439 /// traverse_left, traverse_right and traverse_complete are
440 /// used to initialize Entries/MutEntries
441 /// pointing to element inside tree structure.
443 /// They should be used in following manner:
444 /// - create iterator using TreeMap::[mut_]iter_for_traversal
445 /// - find required node using `traverse_left`/`traverse_right`
446 /// (current node is `Entries::node` field)
447 /// - complete initialization with `traverse_complete`
449 /// After this, iteration will start from `self.node`. If
450 /// `self.node` is None iteration will start from last
451 /// node from which we traversed left.
453 fn traverse_left(&mut self) {
454 let node = unsafe {addr!(& $($addr_mut)* *self.node)};
455 self.node = $deref(addr!(& $($addr_mut)* node.left));
456 self.stack.push(node);
460 fn traverse_right(&mut self) {
461 let node = unsafe {addr!(& $($addr_mut)* *self.node)};
462 self.node = $deref(addr!(& $($addr_mut)* node.right));
466 fn traverse_complete(&mut self) {
467 if !self.node.is_null() {
469 self.stack.push(addr!(& $($addr_mut)* *self.node));
471 self.node = ptr::RawPtr::null();
476 // the forward Iterator impl.
477 item!(impl<'a, K, V> Iterator<(&'a K, &'a $($addr_mut)* V)> for $name<'a, K, V> {
478 /// Advance the iterator to the next node (in order) and return a
479 /// tuple with a reference to the key and value. If there are no
480 /// more nodes, return `None`.
481 fn next(&mut self) -> Option<(&'a K, &'a $($addr_mut)* V)> {
486 fn size_hint(&self) -> (uint, Option<uint>) {
487 (self.remaining_min, Some(self.remaining_max))
491 // the reverse Iterator impl.
492 item!(impl<'a, K, V> Iterator<(&'a K, &'a $($addr_mut)* V)> for $rev_name<'a, K, V> {
493 fn next(&mut self) -> Option<(&'a K, &'a $($addr_mut)* V)> {
494 self.iter.next_(false)
498 fn size_hint(&self) -> (uint, Option<uint>) {
499 self.iter.size_hint()
503 } // end of define_iterator
510 // immutable, so no mut
521 fn deref<'a, K, V>(node: &'a Option<Box<TreeNode<K, V>>>) -> *const TreeNode<K, V> {
524 let n: &TreeNode<K, V> = &**n;
525 n as *const TreeNode<K, V>
531 fn mut_deref<K, V>(x: &mut Option<Box<TreeNode<K, V>>>)
532 -> *mut TreeNode<K, V> {
535 let n: &mut TreeNode<K, V> = &mut **n;
536 n as *mut TreeNode<K, V>
538 None => ptr::mut_null()
544 /// Lazy forward iterator over a map that consumes the map while iterating
545 pub struct MoveEntries<K, V> {
546 stack: Vec<TreeNode<K, V>>,
550 impl<K, V> Iterator<(K, V)> for MoveEntries<K,V> {
552 fn next(&mut self) -> Option<(K, V)> {
553 while !self.stack.is_empty() {
560 } = self.stack.pop().unwrap();
572 self.stack.push(left);
576 Some(box right) => self.stack.push(right),
580 return Some((key, value))
588 fn size_hint(&self) -> (uint, Option<uint>) {
589 (self.remaining, Some(self.remaining))
594 impl<'a, T> Iterator<&'a T> for SetItems<'a, T> {
596 fn next(&mut self) -> Option<&'a T> {
597 self.iter.next().map(|(value, _)| value)
601 impl<'a, T> Iterator<&'a T> for RevSetItems<'a, T> {
603 fn next(&mut self) -> Option<&'a T> {
604 self.iter.next().map(|(value, _)| value)
608 /// A implementation of the `Set` trait on top of the `TreeMap` container. The
609 /// only requirement is that the type of the elements contained ascribes to the
615 /// use std::collections::TreeSet;
617 /// let mut tree_set = TreeSet::new();
619 /// tree_set.insert(2i);
620 /// tree_set.insert(1i);
621 /// tree_set.insert(3i);
623 /// for i in tree_set.iter() {
624 /// println!("{}", i) // prints 1, then 2, then 3
628 pub struct TreeSet<T> {
632 impl<T: PartialEq + Ord> PartialEq for TreeSet<T> {
634 fn eq(&self, other: &TreeSet<T>) -> bool { self.map == other.map }
637 impl<T: Ord> PartialOrd for TreeSet<T> {
639 fn partial_cmp(&self, other: &TreeSet<T>) -> Option<Ordering> {
640 self.map.partial_cmp(&other.map)
644 impl<T: Ord + Show> Show for TreeSet<T> {
645 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
646 try!(write!(f, "{{"));
648 for (i, x) in self.iter().enumerate() {
649 if i != 0 { try!(write!(f, ", ")); }
650 try!(write!(f, "{}", *x));
657 impl<T: Ord> Collection for TreeSet<T> {
659 fn len(&self) -> uint { self.map.len() }
662 impl<T: Ord> Mutable for TreeSet<T> {
664 fn clear(&mut self) { self.map.clear() }
667 impl<T: Ord> Set<T> for TreeSet<T> {
669 fn contains(&self, value: &T) -> bool {
670 self.map.contains_key(value)
673 fn is_disjoint(&self, other: &TreeSet<T>) -> bool {
674 self.intersection(other).next().is_none()
677 fn is_subset(&self, other: &TreeSet<T>) -> bool {
678 let mut x = self.iter();
679 let mut y = other.iter();
680 let mut a = x.next();
681 let mut b = y.next();
692 Greater => return false,
693 Equal => a = x.next(),
702 impl<T: Ord> MutableSet<T> for TreeSet<T> {
704 fn insert(&mut self, value: T) -> bool { self.map.insert(value, ()) }
707 fn remove(&mut self, value: &T) -> bool { self.map.remove(value) }
710 impl<T: Ord> Default for TreeSet<T> {
712 fn default() -> TreeSet<T> { TreeSet::new() }
715 impl<T: Ord> TreeSet<T> {
716 /// Create an empty TreeSet
718 pub fn new() -> TreeSet<T> { TreeSet{map: TreeMap::new()} }
720 /// Get a lazy iterator over the values in the set.
721 /// Requires that it be frozen (immutable).
723 pub fn iter<'a>(&'a self) -> SetItems<'a, T> {
724 SetItems{iter: self.map.iter()}
727 /// Get a lazy iterator over the values in the set.
728 /// Requires that it be frozen (immutable).
730 pub fn rev_iter<'a>(&'a self) -> RevSetItems<'a, T> {
731 RevSetItems{iter: self.map.rev_iter()}
734 /// Get a lazy iterator that consumes the set.
736 pub fn move_iter(self) -> MoveSetItems<T> {
737 self.map.move_iter().map(|(value, _)| value)
740 /// Get a lazy iterator pointing to the first value not less than `v` (greater or equal).
741 /// If all elements in the set are less than `v` empty iterator is returned.
743 pub fn lower_bound<'a>(&'a self, v: &T) -> SetItems<'a, T> {
744 SetItems{iter: self.map.lower_bound(v)}
747 /// Get a lazy iterator pointing to the first value greater than `v`.
748 /// If all elements in the set are not greater than `v` empty iterator is returned.
750 pub fn upper_bound<'a>(&'a self, v: &T) -> SetItems<'a, T> {
751 SetItems{iter: self.map.upper_bound(v)}
754 /// Visit the values (in-order) representing the difference
755 pub fn difference<'a>(&'a self, other: &'a TreeSet<T>) -> DifferenceItems<'a, T> {
756 DifferenceItems{a: self.iter().peekable(), b: other.iter().peekable()}
759 /// Visit the values (in-order) representing the symmetric difference
760 pub fn symmetric_difference<'a>(&'a self, other: &'a TreeSet<T>)
761 -> SymDifferenceItems<'a, T> {
762 SymDifferenceItems{a: self.iter().peekable(), b: other.iter().peekable()}
765 /// Visit the values (in-order) representing the intersection
766 pub fn intersection<'a>(&'a self, other: &'a TreeSet<T>)
767 -> IntersectionItems<'a, T> {
768 IntersectionItems{a: self.iter().peekable(), b: other.iter().peekable()}
771 /// Visit the values (in-order) representing the union
772 pub fn union<'a>(&'a self, other: &'a TreeSet<T>) -> UnionItems<'a, T> {
773 UnionItems{a: self.iter().peekable(), b: other.iter().peekable()}
777 /// Lazy forward iterator over a set
778 pub struct SetItems<'a, T> {
779 iter: Entries<'a, T, ()>
782 /// Lazy backward iterator over a set
783 pub struct RevSetItems<'a, T> {
784 iter: RevEntries<'a, T, ()>
787 /// Lazy forward iterator over a set that consumes the set while iterating
788 pub type MoveSetItems<T> = iter::Map<'static, (T, ()), T, MoveEntries<T, ()>>;
790 /// Lazy iterator producing elements in the set difference (in-order)
791 pub struct DifferenceItems<'a, T> {
792 a: Peekable<&'a T, SetItems<'a, T>>,
793 b: Peekable<&'a T, SetItems<'a, T>>,
796 /// Lazy iterator producing elements in the set symmetric difference (in-order)
797 pub struct SymDifferenceItems<'a, T> {
798 a: Peekable<&'a T, SetItems<'a, T>>,
799 b: Peekable<&'a T, SetItems<'a, T>>,
802 /// Lazy iterator producing elements in the set intersection (in-order)
803 pub struct IntersectionItems<'a, T> {
804 a: Peekable<&'a T, SetItems<'a, T>>,
805 b: Peekable<&'a T, SetItems<'a, T>>,
808 /// Lazy iterator producing elements in the set union (in-order)
809 pub struct UnionItems<'a, T> {
810 a: Peekable<&'a T, SetItems<'a, T>>,
811 b: Peekable<&'a T, SetItems<'a, T>>,
814 /// Compare `x` and `y`, but return `short` if x is None and `long` if y is None
815 fn cmp_opt<T: Ord>(x: Option<&T>, y: Option<&T>,
816 short: Ordering, long: Ordering) -> Ordering {
818 (None , _ ) => short,
820 (Some(x1), Some(y1)) => x1.cmp(y1),
824 impl<'a, T: Ord> Iterator<&'a T> for DifferenceItems<'a, T> {
825 fn next(&mut self) -> Option<&'a T> {
827 match cmp_opt(self.a.peek(), self.b.peek(), Less, Less) {
828 Less => return self.a.next(),
829 Equal => { self.a.next(); self.b.next(); }
830 Greater => { self.b.next(); }
836 impl<'a, T: Ord> Iterator<&'a T> for SymDifferenceItems<'a, T> {
837 fn next(&mut self) -> Option<&'a T> {
839 match cmp_opt(self.a.peek(), self.b.peek(), Greater, Less) {
840 Less => return self.a.next(),
841 Equal => { self.a.next(); self.b.next(); }
842 Greater => return self.b.next(),
848 impl<'a, T: Ord> Iterator<&'a T> for IntersectionItems<'a, T> {
849 fn next(&mut self) -> Option<&'a T> {
851 let o_cmp = match (self.a.peek(), self.b.peek()) {
854 (Some(a1), Some(b1)) => Some(a1.cmp(b1)),
858 Some(Less) => { self.a.next(); }
859 Some(Equal) => { self.b.next(); return self.a.next() }
860 Some(Greater) => { self.b.next(); }
866 impl<'a, T: Ord> Iterator<&'a T> for UnionItems<'a, T> {
867 fn next(&mut self) -> Option<&'a T> {
869 match cmp_opt(self.a.peek(), self.b.peek(), Greater, Less) {
870 Less => return self.a.next(),
871 Equal => { self.b.next(); return self.a.next() }
872 Greater => return self.b.next(),
879 // Nodes keep track of their level in the tree, starting at 1 in the
880 // leaves and with a red child sharing the level of the parent.
882 struct TreeNode<K, V> {
885 left: Option<Box<TreeNode<K, V>>>,
886 right: Option<Box<TreeNode<K, V>>>,
890 impl<K: Ord, V> TreeNode<K, V> {
891 /// Creates a new tree node.
893 pub fn new(key: K, value: V) -> TreeNode<K, V> {
894 TreeNode{key: key, value: value, left: None, right: None, level: 1}
898 // Remove left horizontal link by rotating right
899 fn skew<K: Ord, V>(node: &mut Box<TreeNode<K, V>>) {
900 if node.left.as_ref().map_or(false, |x| x.level == node.level) {
901 let mut save = node.left.take_unwrap();
902 swap(&mut node.left, &mut save.right); // save.right now None
903 swap(node, &mut save);
904 node.right = Some(save);
908 // Remove dual horizontal link by rotating left and increasing level of
910 fn split<K: Ord, V>(node: &mut Box<TreeNode<K, V>>) {
911 if node.right.as_ref().map_or(false,
912 |x| x.right.as_ref().map_or(false, |y| y.level == node.level)) {
913 let mut save = node.right.take_unwrap();
914 swap(&mut node.right, &mut save.left); // save.left now None
916 swap(node, &mut save);
917 node.left = Some(save);
921 // Next 2 functions have the same convention: comparator gets
922 // at input current key and returns search_key cmp cur_key
923 // (i.e. search_key.cmp(&cur_key))
924 fn tree_find_with<'r, K, V>(node: &'r Option<Box<TreeNode<K, V>>>,
925 f: |&K| -> Ordering) -> Option<&'r V> {
926 let mut current: &'r Option<Box<TreeNode<K, V>>> = node;
931 Less => current = &r.left,
932 Greater => current = &r.right,
933 Equal => return Some(&r.value)
941 // See comments above tree_find_with
942 fn tree_find_mut_with<'r, K, V>(node: &'r mut Option<Box<TreeNode<K, V>>>,
943 f: |&K| -> Ordering) -> Option<&'r mut V> {
945 let mut current = node;
947 let temp = current; // hack to appease borrowck
951 Less => current = &mut r.left,
952 Greater => current = &mut r.right,
953 Equal => return Some(&mut r.value)
961 fn insert<K: Ord, V>(node: &mut Option<Box<TreeNode<K, V>>>,
962 key: K, value: V) -> Option<V> {
964 Some(ref mut save) => {
965 match key.cmp(&save.key) {
967 let inserted = insert(&mut save.left, key, value);
973 let inserted = insert(&mut save.right, key, value);
980 Some(replace(&mut save.value, value))
985 *node = Some(box TreeNode::new(key, value));
991 fn remove<K: Ord, V>(node: &mut Option<Box<TreeNode<K, V>>>,
992 key: &K) -> Option<V> {
993 fn heir_swap<K: Ord, V>(node: &mut Box<TreeNode<K, V>>,
994 child: &mut Option<Box<TreeNode<K, V>>>) {
995 // *could* be done without recursion, but it won't borrow check
996 for x in child.mut_iter() {
997 if x.right.is_some() {
998 heir_swap(node, &mut x.right);
1000 swap(&mut node.key, &mut x.key);
1001 swap(&mut node.value, &mut x.value);
1008 return None; // bottom of tree
1010 Some(ref mut save) => {
1011 let (ret, rebalance) = match key.cmp(&save.key) {
1012 Less => (remove(&mut save.left, key), true),
1013 Greater => (remove(&mut save.right, key), true),
1015 if save.left.is_some() {
1016 if save.right.is_some() {
1017 let mut left = save.left.take_unwrap();
1018 if left.right.is_some() {
1019 heir_swap(save, &mut left.right);
1021 swap(&mut save.key, &mut left.key);
1022 swap(&mut save.value, &mut left.value);
1024 save.left = Some(left);
1025 (remove(&mut save.left, key), true)
1027 let new = save.left.take_unwrap();
1028 let box TreeNode{value, ..} = replace(save, new);
1029 *save = save.left.take_unwrap();
1032 } else if save.right.is_some() {
1033 let new = save.right.take_unwrap();
1034 let box TreeNode{value, ..} = replace(save, new);
1043 let left_level = save.left.as_ref().map_or(0, |x| x.level);
1044 let right_level = save.right.as_ref().map_or(0, |x| x.level);
1046 // re-balance, if necessary
1047 if left_level < save.level - 1 || right_level < save.level - 1 {
1050 if right_level > save.level {
1051 for x in save.right.mut_iter() { x.level = save.level }
1056 for right in save.right.mut_iter() {
1058 for x in right.right.mut_iter() { skew(x) }
1062 for x in save.right.mut_iter() { split(x) }
1069 return match node.take() {
1070 Some(box TreeNode{value, ..}) => Some(value), None => fail!()
1074 impl<K: Ord, V> FromIterator<(K, V)> for TreeMap<K, V> {
1075 fn from_iter<T: Iterator<(K, V)>>(iter: T) -> TreeMap<K, V> {
1076 let mut map = TreeMap::new();
1082 impl<K: Ord, V> Extendable<(K, V)> for TreeMap<K, V> {
1084 fn extend<T: Iterator<(K, V)>>(&mut self, mut iter: T) {
1085 for (k, v) in iter {
1091 impl<S: Writer, K: Ord + Hash<S>, V: Hash<S>> Hash<S> for TreeMap<K, V> {
1092 fn hash(&self, state: &mut S) {
1093 for elt in self.iter() {
1099 impl<T: Ord> FromIterator<T> for TreeSet<T> {
1100 fn from_iter<Iter: Iterator<T>>(iter: Iter) -> TreeSet<T> {
1101 let mut set = TreeSet::new();
1107 impl<T: Ord> Extendable<T> for TreeSet<T> {
1109 fn extend<Iter: Iterator<T>>(&mut self, mut iter: Iter) {
1116 impl<S: Writer, T: Ord + Hash<S>> Hash<S> for TreeSet<T> {
1117 fn hash(&self, state: &mut S) {
1118 for elt in self.iter() {
1126 use std::prelude::*;
1130 use {Map, MutableMap, Mutable};
1131 use super::{TreeMap, TreeNode};
1135 let m: TreeMap<int,int> = TreeMap::new();
1136 assert!(m.find(&5) == None);
1140 fn find_not_found() {
1141 let mut m = TreeMap::new();
1142 assert!(m.insert(1i, 2i));
1143 assert!(m.insert(5i, 3i));
1144 assert!(m.insert(9i, 3i));
1145 assert_eq!(m.find(&2), None);
1149 fn find_with_empty() {
1150 let m: TreeMap<&'static str,int> = TreeMap::new();
1151 assert!(m.find_with(|k| "test".cmp(k)) == None);
1155 fn find_with_not_found() {
1156 let mut m = TreeMap::new();
1157 assert!(m.insert("test1", 2i));
1158 assert!(m.insert("test2", 3i));
1159 assert!(m.insert("test3", 3i));
1160 assert_eq!(m.find_with(|k| "test4".cmp(k)), None);
1164 fn find_with_found() {
1165 let mut m = TreeMap::new();
1166 assert!(m.insert("test1", 2i));
1167 assert!(m.insert("test2", 3i));
1168 assert!(m.insert("test3", 4i));
1169 assert_eq!(m.find_with(|k| "test2".cmp(k)), Some(&3i));
1173 fn test_find_mut() {
1174 let mut m = TreeMap::new();
1175 assert!(m.insert(1i, 12i));
1176 assert!(m.insert(2, 8));
1177 assert!(m.insert(5, 14));
1179 match m.find_mut(&5) {
1180 None => fail!(), Some(x) => *x = new
1182 assert_eq!(m.find(&5), Some(&new));
1186 fn test_find_with_mut() {
1187 let mut m = TreeMap::new();
1188 assert!(m.insert("t1", 12i));
1189 assert!(m.insert("t2", 8));
1190 assert!(m.insert("t5", 14));
1192 match m.find_mut_with(|k| "t5".cmp(k)) {
1193 None => fail!(), Some(x) => *x = new
1195 assert_eq!(m.find_with(|k| "t5".cmp(k)), Some(&new));
1199 fn insert_replace() {
1200 let mut m = TreeMap::new();
1201 assert!(m.insert(5i, 2i));
1202 assert!(m.insert(2, 9));
1203 assert!(!m.insert(2, 11));
1204 assert_eq!(m.find(&2).unwrap(), &11);
1209 let mut m = TreeMap::new();
1211 assert!(m.insert(5i, 11i));
1212 assert!(m.insert(12, -3));
1213 assert!(m.insert(19, 2));
1215 assert!(m.find(&5).is_none());
1216 assert!(m.find(&12).is_none());
1217 assert!(m.find(&19).is_none());
1218 assert!(m.is_empty());
1223 let mut m = TreeMap::new();
1225 let k1 = "foo".as_bytes();
1226 let k2 = "bar".as_bytes();
1227 let v1 = "baz".as_bytes();
1228 let v2 = "foobar".as_bytes();
1230 m.insert(k1.clone(), v1.clone());
1231 m.insert(k2.clone(), v2.clone());
1233 assert_eq!(m.find(&k2), Some(&v2));
1234 assert_eq!(m.find(&k1), Some(&v1));
1237 fn check_equal<K: PartialEq + Ord, V: PartialEq>(ctrl: &[(K, V)],
1238 map: &TreeMap<K, V>) {
1239 assert_eq!(ctrl.is_empty(), map.is_empty());
1240 for x in ctrl.iter() {
1241 let &(ref k, ref v) = x;
1242 assert!(map.find(k).unwrap() == v)
1244 for (map_k, map_v) in map.iter() {
1245 let mut found = false;
1246 for x in ctrl.iter() {
1247 let &(ref ctrl_k, ref ctrl_v) = x;
1248 if *map_k == *ctrl_k {
1249 assert!(*map_v == *ctrl_v);
1258 fn check_left<K: Ord, V>(node: &Option<Box<TreeNode<K, V>>>,
1259 parent: &Box<TreeNode<K, V>>) {
1262 assert_eq!(r.key.cmp(&parent.key), Less);
1263 assert!(r.level == parent.level - 1); // left is black
1264 check_left(&r.left, r);
1265 check_right(&r.right, r, false);
1267 None => assert!(parent.level == 1) // parent is leaf
1271 fn check_right<K: Ord, V>(node: &Option<Box<TreeNode<K, V>>>,
1272 parent: &Box<TreeNode<K, V>>,
1276 assert_eq!(r.key.cmp(&parent.key), Greater);
1277 let red = r.level == parent.level;
1278 if parent_red { assert!(!red) } // no dual horizontal links
1279 // Right red or black
1280 assert!(red || r.level == parent.level - 1);
1281 check_left(&r.left, r);
1282 check_right(&r.right, r, red);
1284 None => assert!(parent.level == 1) // parent is leaf
1288 fn check_structure<K: Ord, V>(map: &TreeMap<K, V>) {
1291 check_left(&r.left, r);
1292 check_right(&r.right, r, false);
1299 fn test_rand_int() {
1300 let mut map: TreeMap<int,int> = TreeMap::new();
1301 let mut ctrl = vec![];
1303 check_equal(ctrl.as_slice(), &map);
1304 assert!(map.find(&5).is_none());
1306 let mut rng: rand::IsaacRng = rand::SeedableRng::from_seed(&[42]);
1308 for _ in range(0u, 3) {
1309 for _ in range(0u, 90) {
1312 if !ctrl.iter().any(|x| x == &(k, v)) {
1313 assert!(map.insert(k, v));
1315 check_structure(&map);
1316 check_equal(ctrl.as_slice(), &map);
1320 for _ in range(0u, 30) {
1321 let r = rng.gen_range(0, ctrl.len());
1322 let (key, _) = ctrl.remove(r).unwrap();
1323 assert!(map.remove(&key));
1324 check_structure(&map);
1325 check_equal(ctrl.as_slice(), &map);
1332 let mut m = TreeMap::new();
1333 assert!(m.insert(3i, 6i));
1334 assert_eq!(m.len(), 1);
1335 assert!(m.insert(0, 0));
1336 assert_eq!(m.len(), 2);
1337 assert!(m.insert(4, 8));
1338 assert_eq!(m.len(), 3);
1339 assert!(m.remove(&3));
1340 assert_eq!(m.len(), 2);
1341 assert!(!m.remove(&5));
1342 assert_eq!(m.len(), 2);
1343 assert!(m.insert(2, 4));
1344 assert_eq!(m.len(), 3);
1345 assert!(m.insert(1, 2));
1346 assert_eq!(m.len(), 4);
1350 fn test_iterator() {
1351 let mut m = TreeMap::new();
1353 assert!(m.insert(3i, 6i));
1354 assert!(m.insert(0, 0));
1355 assert!(m.insert(4, 8));
1356 assert!(m.insert(2, 4));
1357 assert!(m.insert(1, 2));
1360 for (k, v) in m.iter() {
1362 assert_eq!(*v, n * 2);
1369 fn test_interval_iteration() {
1370 let mut m = TreeMap::new();
1371 for i in range(1i, 100i) {
1372 assert!(m.insert(i * 2, i * 4));
1375 for i in range(1i, 198i) {
1376 let mut lb_it = m.lower_bound(&i);
1377 let (&k, &v) = lb_it.next().unwrap();
1380 assert_eq!(lb * 2, v);
1382 let mut ub_it = m.upper_bound(&i);
1383 let (&k, &v) = ub_it.next().unwrap();
1384 let ub = i + 2 - i % 2;
1386 assert_eq!(ub * 2, v);
1388 let mut end_it = m.lower_bound(&199);
1389 assert_eq!(end_it.next(), None);
1393 fn test_rev_iter() {
1394 let mut m = TreeMap::new();
1396 assert!(m.insert(3i, 6i));
1397 assert!(m.insert(0, 0));
1398 assert!(m.insert(4, 8));
1399 assert!(m.insert(2, 4));
1400 assert!(m.insert(1, 2));
1403 for (k, v) in m.rev_iter() {
1405 assert_eq!(*v, n * 2);
1411 fn test_mut_iter() {
1412 let mut m = TreeMap::new();
1413 for i in range(0u, 10) {
1414 assert!(m.insert(i, 100 * i));
1417 for (i, (&k, v)) in m.mut_iter().enumerate() {
1418 *v += k * 10 + i; // 000 + 00 + 0, 100 + 10 + 1, ...
1421 for (&k, &v) in m.iter() {
1422 assert_eq!(v, 111 * k);
1426 fn test_mut_rev_iter() {
1427 let mut m = TreeMap::new();
1428 for i in range(0u, 10) {
1429 assert!(m.insert(i, 100 * i));
1432 for (i, (&k, v)) in m.mut_rev_iter().enumerate() {
1433 *v += k * 10 + (9 - i); // 900 + 90 + (9 - 0), 800 + 80 + (9 - 1), ...
1436 for (&k, &v) in m.iter() {
1437 assert_eq!(v, 111 * k);
1442 fn test_mut_interval_iter() {
1443 let mut m_lower = TreeMap::new();
1444 let mut m_upper = TreeMap::new();
1445 for i in range(1i, 100i) {
1446 assert!(m_lower.insert(i * 2, i * 4));
1447 assert!(m_upper.insert(i * 2, i * 4));
1450 for i in range(1i, 199) {
1451 let mut lb_it = m_lower.mut_lower_bound(&i);
1452 let (&k, v) = lb_it.next().unwrap();
1457 for i in range(0i, 198) {
1458 let mut ub_it = m_upper.mut_upper_bound(&i);
1459 let (&k, v) = ub_it.next().unwrap();
1460 let ub = i + 2 - i % 2;
1465 assert!(m_lower.mut_lower_bound(&199).next().is_none());
1467 assert!(m_upper.mut_upper_bound(&198).next().is_none());
1469 assert!(m_lower.iter().all(|(_, &x)| x == 0));
1470 assert!(m_upper.iter().all(|(_, &x)| x == 0));
1475 let mut a = TreeMap::new();
1476 let mut b = TreeMap::new();
1479 assert!(a.insert(0i, 5i));
1481 assert!(b.insert(0, 4));
1483 assert!(a.insert(5, 19));
1485 assert!(!b.insert(0, 5));
1487 assert!(b.insert(5, 19));
1493 let mut a = TreeMap::new();
1494 let mut b = TreeMap::new();
1496 assert!(!(a < b) && !(b < a));
1497 assert!(b.insert(0i, 5i));
1499 assert!(a.insert(0, 7));
1500 assert!(!(a < b) && b < a);
1501 assert!(b.insert(-2, 0));
1503 assert!(a.insert(-5, 2));
1505 assert!(a.insert(6, 2));
1506 assert!(a < b && !(b < a));
1511 let mut a = TreeMap::new();
1512 let mut b = TreeMap::new();
1514 assert!(a <= b && a >= b);
1515 assert!(a.insert(1i, 1i));
1516 assert!(a > b && a >= b);
1517 assert!(b < a && b <= a);
1518 assert!(b.insert(2, 2));
1519 assert!(b > a && b >= a);
1520 assert!(a < b && a <= b);
1525 let mut map: TreeMap<int, int> = TreeMap::new();
1526 let empty: TreeMap<int, int> = TreeMap::new();
1531 let map_str = format!("{}", map);
1533 assert!(map_str == "{1: 2, 3: 4}".to_string());
1534 assert_eq!(format!("{}", empty), "{}".to_string());
1538 fn test_lazy_iterator() {
1539 let mut m = TreeMap::new();
1540 let (x1, y1) = (2i, 5i);
1541 let (x2, y2) = (9, 12);
1542 let (x3, y3) = (20, -3);
1543 let (x4, y4) = (29, 5);
1544 let (x5, y5) = (103, 3);
1546 assert!(m.insert(x1, y1));
1547 assert!(m.insert(x2, y2));
1548 assert!(m.insert(x3, y3));
1549 assert!(m.insert(x4, y4));
1550 assert!(m.insert(x5, y5));
1553 let mut a = m.iter();
1555 assert_eq!(a.next().unwrap(), (&x1, &y1));
1556 assert_eq!(a.next().unwrap(), (&x2, &y2));
1557 assert_eq!(a.next().unwrap(), (&x3, &y3));
1558 assert_eq!(a.next().unwrap(), (&x4, &y4));
1559 assert_eq!(a.next().unwrap(), (&x5, &y5));
1561 assert!(a.next().is_none());
1563 let mut b = m.iter();
1565 let expected = [(&x1, &y1), (&x2, &y2), (&x3, &y3), (&x4, &y4),
1570 assert_eq!(expected[i], x);
1579 assert_eq!(expected[i], x);
1585 fn test_from_iter() {
1586 let xs = [(1i, 1i), (2, 2), (3, 3), (4, 4), (5, 5), (6, 6)];
1588 let map: TreeMap<int, int> = xs.iter().map(|&x| x).collect();
1590 for &(k, v) in xs.iter() {
1591 assert_eq!(map.find(&k), Some(&v));
1602 use deque::bench::{insert_rand_n, insert_seq_n, find_rand_n, find_seq_n};
1606 pub fn insert_rand_100(b: &mut Bencher) {
1607 let mut m : TreeMap<uint,uint> = TreeMap::new();
1608 insert_rand_n(100, &mut m, b);
1612 pub fn insert_rand_10_000(b: &mut Bencher) {
1613 let mut m : TreeMap<uint,uint> = TreeMap::new();
1614 insert_rand_n(10_000, &mut m, b);
1619 pub fn insert_seq_100(b: &mut Bencher) {
1620 let mut m : TreeMap<uint,uint> = TreeMap::new();
1621 insert_seq_n(100, &mut m, b);
1625 pub fn insert_seq_10_000(b: &mut Bencher) {
1626 let mut m : TreeMap<uint,uint> = TreeMap::new();
1627 insert_seq_n(10_000, &mut m, b);
1632 pub fn find_rand_100(b: &mut Bencher) {
1633 let mut m : TreeMap<uint,uint> = TreeMap::new();
1634 find_rand_n(100, &mut m, b);
1638 pub fn find_rand_10_000(b: &mut Bencher) {
1639 let mut m : TreeMap<uint,uint> = TreeMap::new();
1640 find_rand_n(10_000, &mut m, b);
1645 pub fn find_seq_100(b: &mut Bencher) {
1646 let mut m : TreeMap<uint,uint> = TreeMap::new();
1647 find_seq_n(100, &mut m, b);
1651 pub fn find_seq_10_000(b: &mut Bencher) {
1652 let mut m : TreeMap<uint,uint> = TreeMap::new();
1653 find_seq_n(10_000, &mut m, b);
1659 use std::prelude::*;
1662 use {Set, MutableSet, Mutable, MutableMap};
1663 use super::{TreeMap, TreeSet};
1667 let mut s = TreeSet::new();
1669 assert!(s.insert(5i));
1670 assert!(s.insert(12));
1671 assert!(s.insert(19));
1673 assert!(!s.contains(&5));
1674 assert!(!s.contains(&12));
1675 assert!(!s.contains(&19));
1676 assert!(s.is_empty());
1680 fn test_disjoint() {
1681 let mut xs = TreeSet::new();
1682 let mut ys = TreeSet::new();
1683 assert!(xs.is_disjoint(&ys));
1684 assert!(ys.is_disjoint(&xs));
1685 assert!(xs.insert(5i));
1686 assert!(ys.insert(11i));
1687 assert!(xs.is_disjoint(&ys));
1688 assert!(ys.is_disjoint(&xs));
1689 assert!(xs.insert(7));
1690 assert!(xs.insert(19));
1691 assert!(xs.insert(4));
1692 assert!(ys.insert(2));
1693 assert!(ys.insert(-11));
1694 assert!(xs.is_disjoint(&ys));
1695 assert!(ys.is_disjoint(&xs));
1696 assert!(ys.insert(7));
1697 assert!(!xs.is_disjoint(&ys));
1698 assert!(!ys.is_disjoint(&xs));
1702 fn test_subset_and_superset() {
1703 let mut a = TreeSet::new();
1704 assert!(a.insert(0i));
1705 assert!(a.insert(5));
1706 assert!(a.insert(11));
1707 assert!(a.insert(7));
1709 let mut b = TreeSet::new();
1710 assert!(b.insert(0i));
1711 assert!(b.insert(7));
1712 assert!(b.insert(19));
1713 assert!(b.insert(250));
1714 assert!(b.insert(11));
1715 assert!(b.insert(200));
1717 assert!(!a.is_subset(&b));
1718 assert!(!a.is_superset(&b));
1719 assert!(!b.is_subset(&a));
1720 assert!(!b.is_superset(&a));
1722 assert!(b.insert(5));
1724 assert!(a.is_subset(&b));
1725 assert!(!a.is_superset(&b));
1726 assert!(!b.is_subset(&a));
1727 assert!(b.is_superset(&a));
1731 fn test_iterator() {
1732 let mut m = TreeSet::new();
1734 assert!(m.insert(3i));
1735 assert!(m.insert(0));
1736 assert!(m.insert(4));
1737 assert!(m.insert(2));
1738 assert!(m.insert(1));
1748 fn test_rev_iter() {
1749 let mut m = TreeSet::new();
1751 assert!(m.insert(3i));
1752 assert!(m.insert(0));
1753 assert!(m.insert(4));
1754 assert!(m.insert(2));
1755 assert!(m.insert(1));
1758 for x in m.rev_iter() {
1765 fn test_move_iter() {
1766 let s: TreeSet<int> = range(0i, 5).collect();
1769 for x in s.move_iter() {
1776 fn test_move_iter_size_hint() {
1777 let s: TreeSet<int> = vec!(0i, 1).move_iter().collect();
1779 let mut it = s.move_iter();
1781 assert_eq!(it.size_hint(), (2, Some(2)));
1782 assert!(it.next() != None);
1784 assert_eq!(it.size_hint(), (1, Some(1)));
1785 assert!(it.next() != None);
1787 assert_eq!(it.size_hint(), (0, Some(0)));
1788 assert_eq!(it.next(), None);
1792 fn test_clone_eq() {
1793 let mut m = TreeSet::new();
1798 assert!(m.clone() == m);
1803 let mut x = TreeSet::new();
1804 let mut y = TreeSet::new();
1814 assert!(hash::hash(&x) == hash::hash(&y));
1820 f: |&TreeSet<int>, &TreeSet<int>, f: |&int| -> bool| -> bool) {
1821 let mut set_a = TreeSet::new();
1822 let mut set_b = TreeSet::new();
1824 for x in a.iter() { assert!(set_a.insert(*x)) }
1825 for y in b.iter() { assert!(set_b.insert(*y)) }
1828 f(&set_a, &set_b, |x| {
1829 assert_eq!(*x, expected[i]);
1833 assert_eq!(i, expected.len());
1837 fn test_intersection() {
1838 fn check_intersection(a: &[int], b: &[int], expected: &[int]) {
1839 check(a, b, expected, |x, y, f| x.intersection(y).all(f))
1842 check_intersection([], [], []);
1843 check_intersection([1, 2, 3], [], []);
1844 check_intersection([], [1, 2, 3], []);
1845 check_intersection([2], [1, 2, 3], [2]);
1846 check_intersection([1, 2, 3], [2], [2]);
1847 check_intersection([11, 1, 3, 77, 103, 5, -5],
1848 [2, 11, 77, -9, -42, 5, 3],
1853 fn test_difference() {
1854 fn check_difference(a: &[int], b: &[int], expected: &[int]) {
1855 check(a, b, expected, |x, y, f| x.difference(y).all(f))
1858 check_difference([], [], []);
1859 check_difference([1, 12], [], [1, 12]);
1860 check_difference([], [1, 2, 3, 9], []);
1861 check_difference([1, 3, 5, 9, 11],
1864 check_difference([-5, 11, 22, 33, 40, 42],
1865 [-12, -5, 14, 23, 34, 38, 39, 50],
1866 [11, 22, 33, 40, 42]);
1870 fn test_symmetric_difference() {
1871 fn check_symmetric_difference(a: &[int], b: &[int],
1873 check(a, b, expected, |x, y, f| x.symmetric_difference(y).all(f))
1876 check_symmetric_difference([], [], []);
1877 check_symmetric_difference([1, 2, 3], [2], [1, 3]);
1878 check_symmetric_difference([2], [1, 2, 3], [1, 3]);
1879 check_symmetric_difference([1, 3, 5, 9, 11],
1881 [-2, 1, 5, 11, 14, 22]);
1886 fn check_union(a: &[int], b: &[int],
1888 check(a, b, expected, |x, y, f| x.union(y).all(f))
1891 check_union([], [], []);
1892 check_union([1, 2, 3], [2], [1, 2, 3]);
1893 check_union([2], [1, 2, 3], [1, 2, 3]);
1894 check_union([1, 3, 5, 9, 11, 16, 19, 24],
1895 [-2, 1, 5, 9, 13, 19],
1896 [-2, 1, 3, 5, 9, 11, 13, 16, 19, 24]);
1901 let mut x = TreeSet::new();
1906 let mut y = TreeSet::new();
1912 let mut z = x.iter().zip(y.iter());
1914 // FIXME: #5801: this needs a type hint to compile...
1915 let result: Option<(&uint, & &'static str)> = z.next();
1916 assert_eq!(result.unwrap(), (&5u, &("bar")));
1918 let result: Option<(&uint, & &'static str)> = z.next();
1919 assert_eq!(result.unwrap(), (&11u, &("foo")));
1921 let result: Option<(&uint, & &'static str)> = z.next();
1922 assert!(result.is_none());
1927 let mut m = TreeMap::new();
1928 assert_eq!(m.swap(1u, 2i), None);
1929 assert_eq!(m.swap(1u, 3i), Some(2));
1930 assert_eq!(m.swap(1u, 4i), Some(3));
1935 let mut m = TreeMap::new();
1937 assert_eq!(m.pop(&1), Some(2));
1938 assert_eq!(m.pop(&1), None);
1942 fn test_from_iter() {
1943 let xs = [1i, 2, 3, 4, 5, 6, 7, 8, 9];
1945 let set: TreeSet<int> = xs.iter().map(|&x| x).collect();
1947 for x in xs.iter() {
1948 assert!(set.contains(x));
1954 let mut set: TreeSet<int> = TreeSet::new();
1955 let empty: TreeSet<int> = TreeSet::new();
1960 let set_str = format!("{}", set);
1962 assert!(set_str == "{1, 2}".to_string());
1963 assert_eq!(format!("{}", empty), "{}".to_string());