Merge pull request #970 from Unity-Technologies/unity-master-list-add-range-avoid-allocation

joncham · web-flow · commit bee08b6838c0 · 2018-06-01T16:01:55.000-04:00
Avoid temporary allocation in List.AddRange (case 1041305)
diff --git a/mcs/class/referencesource/mscorlib/system/collections/generic/list.cs b/mcs/class/referencesource/mscorlib/system/collections/generic/list.cs
@@ -732,9 +732,13 @@ public void InsertRange(int index, IEnumerable<T> collection) {
                         Array.Copy(_items, index+count, _items, index*2, _size-index);
                     }
                     else {
+#if MONO
+                        c.CopyTo(_items, index);
+#else
                         T[] itemsToInsert = new T[count];
                         c.CopyTo(itemsToInsert, 0);
                         itemsToInsert.CopyTo(_items, index);                    
+#endif
                     }
                     _size += count;
                 }                

Original file line number	Diff line number	Diff line change
`@@ -732,9 +732,13 @@ public void InsertRange(int index, IEnumerable<T> collection) {`
`732`	`732`	`Array.Copy(_items, index+count, _items, index*2, _size-index);`
`733`	`733`	`}`
`734`	`734`	`else {`
	`735`	`+#if MONO`
	`736`	`+ c.CopyTo(_items, index);`
	`737`	`+#else`
`735`	`738`	`T[] itemsToInsert = new T[count];`
`736`	`739`	`c.CopyTo(itemsToInsert, 0);`
`737`	`740`	`itemsToInsert.CopyTo(_items, index);`
	`741`	`+#endif`
`738`	`742`	`}`
`739`	`743`	`_size += count;`
`740`	`744`	`}`