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quiver/lib/src/iterables/partition.dart

-// Copyright 2014 Google Inc. All Rights Reserved.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-part of quiver.iterables;
-
-/**
- * Partitions the input iterable into lists of the specified size.
- */
-Iterable<List> partition(Iterable iterable, int size) {
-  return iterable.isEmpty ? [] : new _Partition(iterable, size);
-}
-
-class _Partition extends IterableBase<List> {
-  final Iterable _iterable;
-  final int _size;
-
-  _Partition(this._iterable, this._size) {
-    if (_size <= 0) throw new ArgumentError(_size);
-  }
-
-  Iterator<List> get iterator =>
-      new _PartitionIterator(_iterable.iterator, _size);
-}
-
-class _PartitionIterator implements Iterator<List> {
-  final Iterator _iterator;
-  final int _size;
-  List _current;
-
-  _PartitionIterator(this._iterator, this._size);
-
-  @override
-  List get current => _current;
-
-  @override
-  bool moveNext() {
-    var newValue = [];
-    var count = 0;
-    for (; count < _size && _iterator.moveNext(); count++) {
-      newValue.add(_iterator.current);
-    }
-    _current = (count > 0) ? newValue : null;
-    return _current != null;
-  }
-}