tree::TreeIter: Implement nth to make jumping ahead more efficient

joshtriplett · joshtriplett · commit 2be11ddb5de2 · 2023-12-31T13:11:23.000-08:00
This means `skip` (which uses `nth`) will also be more efficient.
diff --git a/src/tree.rs b/src/tree.rs
@@ -397,6 +397,9 @@ impl<'tree> Iterator for TreeIter<'tree> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         self.range.size_hint()
     }
+    fn nth(&mut self, n: usize) -> Option<TreeEntry<'tree>> {
+        self.range.nth(n).and_then(|i| self.tree.get(i))
+    }
 }
 impl<'tree> DoubleEndedIterator for TreeIter<'tree> {
     fn next_back(&mut self) -> Option<TreeEntry<'tree>> {

Original file line number	Diff line number	Diff line change
`@@ -397,6 +397,9 @@ impl<'tree> Iterator for TreeIter<'tree> {`
`397`	`397`	`fn size_hint(&self) -> (usize, Option<usize>) {`
`398`	`398`	`self.range.size_hint()`
`399`	`399`	`}`
	`400`	`+ fn nth(&mut self, n: usize) -> Option<TreeEntry<'tree>> {`
	`401`	`+ self.range.nth(n).and_then(\|i\| self.tree.get(i))`
	`402`	`+ }`
`400`	`403`	`}`
`401`	`404`	`impl<'tree> DoubleEndedIterator for TreeIter<'tree> {`
`402`	`405`	`fn next_back(&mut self) -> Option<TreeEntry<'tree>> {`