Refactor List.setRange function.

sdk/lib/_collection_dev/iterable.dart

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of dart._collection.dev;
 
 /**
  * An [Iterable] for classes that have efficient [length] and [elementAt].
  *
  * All other methods are implemented in terms of [length] and [elementAt],
@@ skipping 913 matching lines @@
     if (start < 0 || start > list.length) {
       throw new RangeError.range(start, 0, list.length);
     }
     if (end < start || end > list.length) {
       throw new RangeError.range(end, start, list.length);
     }
     // The generic type is currently lost. It will be fixed with mixins.
     return new SubListIterable(list, start, end);
   }
 
-  static void setRangeList(List list, int start, int length,
-                           List from, int startFrom) {
+  static void setRangeList(List list, int start, int end,
+                           Iterable from, int skipCount) {
+    if (start < 0 || start > list.length) {
+      throw new RangeError.range(start, 0, list.length);
+    }
+    if (end < start || end > list.length) {
+      throw new RangeError.range(end, start, list.length);
+    }
+    int length = end - start;
     if (length == 0) return;
 
-    if (length < 0) throw new ArgumentError(length);
-    if (start < 0) throw new RangeError.value(start);
-    if (start + length > list.length) {
-      throw new RangeError.value(start + length);
+    if (skipCount < 0) throw new ArgumentError(skipCount);
+
+    // TODO(floitsch): Make this accept more.
+    List otherList;
+    int otherStart;
+    if (from is List) {
+      otherList = from;
+      otherStart = skipCount;
+    } else {
+      otherList = from.skip(skipCount).toList(growable: false);
+      otherStart = 0;
     }
-
-    Arrays.copy(from, startFrom, list, start, length);
+    if (otherStart + length > otherList.length) {
+      throw new StateError("Not enough elements");
+    }
+    Arrays.copy(otherList, otherStart, list, start, length);
   }
 
   static Map<int, dynamic> asMapList(List l) {
     return new ListMapView(l);
   }
 
   static bool setContainsAll(Set set, Iterable other) {
     for (var element in other) {
       if (!set.contains(element)) return false;
     }
@@ skipping 26 matching lines @@
 
   static Set setDifference(Set set, Set other, Set result) {
     for (var element in set) {
       if (!other.contains(element)) {
         result.add(element);
       }
     }
     return result;
   }
 }