System.Xml.Xsl.IlGen.XmlILVisitor.VisitChoice C# (CSharp) Method

        protected override QilNode VisitChoice(QilChoice ndChoice) {
            QilNode ndBranches;
            Label[] switchLabels;
            Label lblOtherwise, lblDone;
            int regBranches, idx;
            Debug.Assert(XmlILConstructInfo.Read(ndChoice).PushToWriterFirst);

            // Evaluate the expression
            NestedVisit(ndChoice.Expression);

            // Generate switching code
            ndBranches = ndChoice.Branches;
            regBranches = ndBranches.Count - 1;
            switchLabels = new Label[regBranches];
            for (idx = 0; idx < regBranches; idx++)
                switchLabels[idx] = this.helper.DefineLabel();

            lblOtherwise = this.helper.DefineLabel();
            lblDone = this.helper.DefineLabel();

            // switch (value)
            //   case 0: goto Label[0];
            //   ...
            //   case N-1: goto Label[N-1];
            //   default: goto LabelOtherwise;
            this.helper.Emit(OpCodes.Switch, switchLabels);
            this.helper.EmitUnconditionalBranch(OpCodes.Br, lblOtherwise);

            for (idx = 0; idx < regBranches; idx++) {
                // Label[i]:
                this.helper.MarkLabel(switchLabels[idx]);

                // Generate regular branch code
                NestedVisit(ndBranches[idx]);

                // goto LabelDone
                this.helper.EmitUnconditionalBranch(OpCodes.Br, lblDone);
            }

            // LabelOtherwise:
            this.helper.MarkLabel(lblOtherwise);

            // Generate otherwise branch code
            NestedVisit(ndBranches[idx]);

            // LabelDone:
            this.helper.MarkLabel(lblDone);

            this.iterCurr.Storage = StorageDescriptor.None();

            return ndChoice;
        }