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priority_queue: avoid copy with top and maybe_top

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Daniel Micay 2012-12-11 12:19:20 -05:00 • committed by Brian Anderson
parent e00c3b05e1
commit 7bd0d71554
1 changed files with 12 additions and 11 deletions
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23
src/libstd/priority_queue.rs
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@ -8,10 +8,10 @@ pub struct PriorityQueue <T: Copy Ord>{
impl <T: Copy Ord> PriorityQueue<T> { impl <T: Copy Ord> PriorityQueue<T> {
/// Returns the greatest item in the queue - fails if empty /// Returns the greatest item in the queue - fails if empty
pure fn top(&self) -> T { self.data[0] } pure fn top(&self) -> &self/T { &self.data[0] }
/// Returns the greatest item in the queue - None if empty /// Returns the greatest item in the queue - None if empty
pure fn maybe_top(&self) -> Option<T> { pure fn maybe_top(&self) -> Option<&self/T> {
if self.is_empty() { None } else { Some(self.top()) } if self.is_empty() { None } else { Some(self.top()) }
} }
@ -151,7 +151,7 @@ mod tests {
let mut sorted = merge_sort(data, le); let mut sorted = merge_sort(data, le);
let mut heap = from_vec(data); let mut heap = from_vec(data);
while heap.is_not_empty() { while heap.is_not_empty() {
assert heap.top() == sorted.last(); assert *heap.top() == sorted.last();
assert heap.pop() == sorted.pop(); assert heap.pop() == sorted.pop();
} }
} }
@ -160,22 +160,22 @@ mod tests {
fn test_push() { fn test_push() {
let mut heap = from_vec(~[2, 4, 9]); let mut heap = from_vec(~[2, 4, 9]);
assert heap.len() == 3; assert heap.len() == 3;
assert heap.top() == 9; assert *heap.top() == 9;
heap.push(11); heap.push(11);
assert heap.len() == 4; assert heap.len() == 4;
assert heap.top() == 11; assert *heap.top() == 11;
heap.push(5); heap.push(5);
assert heap.len() == 5; assert heap.len() == 5;
assert heap.top() == 11; assert *heap.top() == 11;
heap.push(27); heap.push(27);
assert heap.len() == 6; assert heap.len() == 6;
assert heap.top() == 27; assert *heap.top() == 27;
heap.push(3); heap.push(3);
assert heap.len() == 7; assert heap.len() == 7;
assert heap.top() == 27; assert *heap.top() == 27;
heap.push(103); heap.push(103);
assert heap.len() == 8; assert heap.len() == 8;
assert heap.top() == 103; assert *heap.top() == 103;
} }
#[test] #[test]
@ -241,11 +241,12 @@ mod tests {
#[test] #[test]
#[should_fail] #[should_fail]
fn test_empty_top() { from_vec::<int>(~[]).top(); } fn test_empty_top() { let empty = from_vec::<int>(~[]); empty.top(); }
#[test] #[test]
fn test_empty_maybe_top() { fn test_empty_maybe_top() {
assert from_vec::<int>(~[]).maybe_top().is_none(); let empty = from_vec::<int>(~[]);
assert empty.maybe_top().is_none();
} }
#[test] #[test]