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pkg/dev_compiler/tool/input_sdk/lib/collection/iterator.dart

-// Copyright (c) 2012, 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;
-
-/**
- * The [HasNextIterator] class wraps an [Iterator] and provides methods to
- * iterate over an object using `hasNext` and `next`.
- *
- * An [HasNextIterator] does not implement the [Iterator] interface.
- */
-class HasNextIterator<E> {
-  static const int _HAS_NEXT_AND_NEXT_IN_CURRENT = 0;
-  static const int _NO_NEXT = 1;
-  static const int _NOT_MOVED_YET = 2;
-
-  Iterator<E> _iterator;
-  int _state = _NOT_MOVED_YET;
-
-  HasNextIterator(this._iterator);
-
-  bool get hasNext {
-    if (_state == _NOT_MOVED_YET) _move();
-    return _state == _HAS_NEXT_AND_NEXT_IN_CURRENT;
-  }
-
-  E next() {
-    // Call to hasNext is necessary to make sure we are positioned at the first
-    // element when we start iterating.
-    if (!hasNext) throw new StateError("No more elements");
-    assert(_state == _HAS_NEXT_AND_NEXT_IN_CURRENT);
-    E result = _iterator.current;
-    _move();
-    return result;
-  }
-
-  void _move() {
-    if (_iterator.moveNext()) {
-      _state = _HAS_NEXT_AND_NEXT_IN_CURRENT;
-    } else {
-      _state = _NO_NEXT;
-    }
-  }
-}