Zip refactoring

MoreLinq/Enumerator.cs

@@ -0,0 +1,66 @@
+#region License and Terms
+// MoreLINQ - Extensions to LINQ to Objects
+// Copyright (c) 2019 Pierre Lando. 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.
+#endregion
+
+namespace MoreLinq
+{
+    using System.Collections.Generic;
+
+    static class Enumerator
+    {
+        /// <summary>
+        /// <para>
+        /// Move the <paramref name="enumerator"/> to the next position and put the
+        /// new current value into <paramref name="item"/>.</para>
+        /// <para>
+        /// If the <paramref name="enumerator"/> has no more element it's disposed and
+        /// set to <c>null</c>, and <paramref name="item"/> is set to <c>default</c>.</para>
+        /// <para>
+        /// If the <paramref name="enumerator"/> is <c>null</c> the method return immediately
+        /// and <paramref name="item"/> is set to <c>null</c>.</para>
+        /// </summary>
+        /// <typeparam name="T">The type of element that are enumerated.</typeparam>
+        /// <param name="enumerator">The enumerator to iterate or dispose.</param>
+        /// <param name="item">The new current value of <paramref name="enumerator"/> or
+        /// <c>default</c> if <paramref name="enumerator"/> has no more element.
+        /// </param>
+        /// <remarks>
+        /// Because <paramref name="enumerator"/> and <paramref name="item"/> may both be modified
+        /// they are both passed by reference.
+        /// </remarks>
+        /// <returns>A <c>bool</c> value indicating if the enumerator has moved to the next element.</returns>
+
+        public static bool TryRead<T>(ref IEnumerator<T>? enumerator, out T? item)
+        {
+            if (enumerator is null)
+            {
+                item = default;
+                return false;
+            }
+
+            if (enumerator.MoveNext())
+            {
+                item = enumerator.Current;
+                return true;
+            }
+
+            enumerator.Dispose();
+            enumerator = null;
+            item = default;
+            return false;
+        }
+    }
+}