Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.Data.SqlXml/System/Xml/Xsl/XsltOld/TemplateBaseAction.cs

@@ -0,0 +1,41 @@
+//------------------------------------------------------------------------------
+// <copyright file="TemplateBaseAction.cs" company="Microsoft">
+//     Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>                                                                
+// <owner current="true" primary="true">[....]</owner>
+//------------------------------------------------------------------------------
+
+namespace System.Xml.Xsl.XsltOld {
+    using Res = System.Xml.Utils.Res;
+    using System;
+    using System.Diagnostics;
+    using System.Collections;
+    using System.Xml;
+    using System.Xml.XPath;
+    using System.Globalization;
+
+    // RootAction and TemplateActions have a litle in common -- they are responsible for variable allocation
+    // TemplateBaseAction -- implenemts this shared behavior
+
+    internal abstract class TemplateBaseAction : ContainerAction {
+        protected int variableCount;      // space to allocate on frame for variables
+        private   int variableFreeSlot;   // compile time counter responsiable for variable placement logic
+
+        public int AllocateVariableSlot() {
+            // Variable placement logic. Optimized
+            int thisSlot = this.variableFreeSlot;
+            this.variableFreeSlot ++;
+            if(this.variableCount < this.variableFreeSlot) {
+                this.variableCount = this.variableFreeSlot;
+            }
+            return thisSlot;
+        }
+
+        public void ReleaseVariableSlots(int n) {
+        // This code does optimisation of variable placement. Comented out for this version
+        //      Reuse of the variable disable the check that variable was assigned before the actual use
+        //      this check has to be done in compile time n future.
+//            this.variableFreeSlot -= n;
+        }
+    }
+}