Import YamlDotNet.

Assets/YamlDotNet/Core/SimpleKey.cs

@@ -0,0 +1,56 @@
+// This file is part of YamlDotNet - A .NET library for YAML.
+// Copyright (c) Antoine Aubry and contributors
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy of
+// this software and associated documentation files (the "Software"), to deal in
+// the Software without restriction, including without limitation the rights to
+// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+// of the Software, and to permit persons to whom the Software is furnished to do
+// so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+namespace YamlDotNet.Core
+{
+    internal sealed class SimpleKey
+    {
+        private readonly Cursor cursor;
+
+        public bool IsPossible { get; private set; }
+
+        public void MarkAsImpossible()
+        {
+            IsPossible = false;
+        }
+
+        public bool IsRequired { get; }
+        public int TokenNumber { get; }
+        public int Index => cursor.Index;
+        public int Line => cursor.Line;
+        public int LineOffset => cursor.LineOffset;
+
+        public Mark Mark => cursor.Mark();
+
+        public SimpleKey()
+        {
+            cursor = new Cursor();
+        }
+
+        public SimpleKey(bool isRequired, int tokenNumber, Cursor cursor)
+        {
+            IsPossible = true;
+            IsRequired = isRequired;
+            TokenNumber = tokenNumber;
+            this.cursor = new Cursor(cursor);
+        }
+    }
+}