From 9ef6e1b463bf697a97ec3cb6ebf1b84d865d2a8c Mon Sep 17 00:00:00 2001
From: rikbellens <rik.bellens@appsup.be>
Date: Mon, 22 Apr 2024 21:11:59 +0200
Subject: [PATCH] perf: improve speed of addAll to empty map

---
 lib/src/sortedmap.dart   |  6 +++++
 lib/src/treemap.dart     |  2 +-
 lib/src/treeset.dart     | 56 ++++++++++++++++++++++++++++++++++++++++
 test/sortedmap_test.dart |  1 -
 4 files changed, 63 insertions(+), 2 deletions(-)

diff --git a/lib/src/sortedmap.dart b/lib/src/sortedmap.dart
index b24e9fe..5a5db24 100644
--- a/lib/src/sortedmap.dart
+++ b/lib/src/sortedmap.dart
@@ -209,6 +209,12 @@ class _SortedMap<K extends Comparable, V> extends MapBase<K, V>
       _map.addAll(other._map);
       return;
     }
+    if (this is! FilteredMap) {
+      _sortedEntries
+          .addAll(other.entries.map((e) => ordering.mapEntry(e.key, e.value)));
+      _map.addAll(other);
+      return;
+    }
     super.addAll(other);
   }
 
diff --git a/lib/src/treemap.dart b/lib/src/treemap.dart
index aca43a3..9e08385 100644
--- a/lib/src/treemap.dart
+++ b/lib/src/treemap.dart
@@ -57,7 +57,7 @@ class TreeMap<K extends Comparable, V> extends MapBase<K, V> {
     if (other is TreeMap<K, V>) {
       _tree.addAll(other._tree);
     } else {
-      super.addAll(other);
+      _tree.addAll(other.entries);
     }
   }
 }
diff --git a/lib/src/treeset.dart b/lib/src/treeset.dart
index 85b8a34..5aa44ba 100644
--- a/lib/src/treeset.dart
+++ b/lib/src/treeset.dart
@@ -387,12 +387,19 @@ class AvlTreeSet<V> extends _BaseTreeSet<V> {
 
   @override
   bool addAll(Iterable<V> items) {
+    if (items.isEmpty) return false;
     if (_root == null &&
         items is AvlTreeSet<V> &&
         identical((items as dynamic).comparator, comparator)) {
       _root = items._root;
       return _root != null;
     }
+    if (_root == null) {
+      //
+      var l = items.toList()..sort(comparator);
+      _root = AvlNode.fromOrderedList(l);
+      return true;
+    }
     var modified = false;
     for (var ele in items) {
       modified = add(ele) ? true : modified;
@@ -690,6 +697,55 @@ class AvlNode<V> {
         height = max(left?.height ?? 0, right?.height ?? 0) + 1,
         length = (left?.length ?? 0) + (right?.length ?? 0) + 1;
 
+  factory AvlNode.fromOrderedList(List<V> items) {
+    var depth = (log(items.length + 1) / ln2).ceil();
+    var size = (1 << depth) - 1;
+
+    var nulls = size - items.length;
+
+    var l = items.cast<V?>();
+    if (nulls > 0) {
+      var nonNulls = (size + 1) ~/ 2 - nulls;
+
+      var spacing = nonNulls;
+
+      var skip = 0;
+      var space = spacing;
+      l = List<V?>.generate(size, (index) {
+        if (index % 2 == 0) {
+          if (space >= spacing) {
+            space -= spacing;
+            skip++;
+            return null;
+          } else {
+            space += nulls - 1;
+          }
+        }
+        return items[index - skip];
+      });
+    }
+
+    var k = List<AvlNode<V>?>.generate(
+        (size + 1) >> 1,
+        (index) => l[index * 2] == null
+            ? null
+            : AvlNode(
+                object: l[index * 2]!,
+              ));
+
+    var skip = 2;
+    while (k.length > 1) {
+      skip *= 2;
+      k = List.generate(k.length >> 1, (index) {
+        return AvlNode(
+            object: l[(skip ~/ 2) - 1 + index * skip]!,
+            left: k[index * 2],
+            right: k[index * 2 + 1]);
+      });
+    }
+    return k.single!;
+  }
+
   int get balanceFactor => (right?.height ?? 0) - (left?.height ?? 0);
 
   AvlNode<V> get minimumNode {
diff --git a/test/sortedmap_test.dart b/test/sortedmap_test.dart
index 5c87935..2232d16 100644
--- a/test/sortedmap_test.dart
+++ b/test/sortedmap_test.dart
@@ -26,7 +26,6 @@ void main() {
       map.addAll({'b': 1, 'e': 2, 'a': 3, 'c': 4});
 
       var keys = map.keys.toList();
-
       expect(keys.indexOf('a'), 0);
       expect(keys.indexOf('b'), 1);
       expect(keys.indexOf('c'), 2);