optiizing array copying

.metals/metals.lock.db

@@ -1,6 +1,6 @@
 #FileLock
-#Mon Jul 12 18:17:00 MSK 2021
-server=localhost\:59825
+#Fri Aug 20 00:03:35 MSK 2021
+server=localhost\:61983
 hostName=localhost
 method=file
-id=17a9b4afbd10ae123e90d5f9833e0743feff1cdb50d
+id=17b6039f25a63e082554dea9fe3c8cce6a94cf45c55

src/ImTools/ImTools.cs

@@ -1618,7 +1618,7 @@ public static T[] Copy<T>(this T[] items)
                 for (var i = 0; i < count; ++i)
                     copy[i] = items[i];
             else
-                Array.Copy(items, copy, count);
+                Array.Copy(items, 0, copy, 0, count);
             return copy;
         }
 
@@ -1631,7 +1631,7 @@ public static T[] CopyNonEmpty<T>(this T[] items)
                 for (var i = 0; i < count; ++i)
                     copy[i] = items[i];
             else
-                Array.Copy(items, copy, count);
+                Array.Copy(items, 0, copy, 0, count);
             return copy;
         }
 
@@ -2710,10 +2710,23 @@ private static T[] Expand(T[] items)
         {
             var count = items.Length;
             var newItems = new T[count << 1]; // count x 2
-            Array.Copy(items, 0, newItems, 0, count);
+            if (count < 6)
+                for (var i = 0; i < count; ++i)
+                    newItems[i] = items[i];
+            else
+                Array.Copy(items, 0, newItems, 0, count);
             return newItems;
         }
 
+        ///<summary>Creates the final array out of the list, so that you cannot use after that!</summary>
+        public T[] BuildArray()
+        {
+            var items = Items;
+            if (Count < items.Length)
+                Array.Resize(ref items, Count); 
+            return items;
+        }
+
         /// <inheritdoc />
         public override string ToString() =>
             $"Count {Count} of {(Count == 0 || Items == null || Items.Length == 0 ? "empty" : "first (" + Items[0] + ") and last (" + Items[Count - 1] + ")")}";