/Users/parrt/antlr/code/antlr/main/runtime/CSharp/Sources/Antlr3.Runtime/Antlr.Runtime.Tree/RewriteRuleSubtreeStream.cs

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/*
[The "BSD licence"]
Copyright (c) 2005-2007 Kunle Odutola
Copyright (c) 2007 Johannes Luber
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code MUST RETAIN the above copyright
   notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form MUST REPRODUCE the above copyright
   notice, this list of conditions and the following disclaimer in 
   the documentation and/or other materials provided with the 
   distribution.
3. The name of the author may not be used to endorse or promote products
   derived from this software without specific prior WRITTEN permission.
4. Unless explicitly state otherwise, any contribution intentionally 
   submitted for inclusion in this work to the copyright owner or licensor
   shall be under the terms and conditions of this license, without any 
   additional terms or conditions.

THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/


#if DOTNET1
namespace Antlr.Runtime.Tree
{
        using System;
        using IList = System.Collections.IList;
        
        public class RewriteRuleSubtreeStream : RewriteRuleElementStream
        {
                public RewriteRuleSubtreeStream(ITreeAdaptor adaptor, string elementDescription)
                        : base(adaptor, elementDescription)
                {
                }
                
                public RewriteRuleSubtreeStream(ITreeAdaptor adaptor, string elementDescription, object oneElement)
                        : base(adaptor, elementDescription, oneElement)
                {
                }
                
                public RewriteRuleSubtreeStream(ITreeAdaptor adaptor, string elementDescription, IList elements)
                        : base(adaptor, elementDescription, elements)
                {
                }
                
                public object NextNode()
                {
                        int size = Size();
                        if (dirty || ((cursor >= size) && (size == 1)))
                        {
                                // if out of elements and size is 1, dup (at most a single node
                                // since this is for making root nodes).
                                object el = _Next();
                                return adaptor.DupNode(el);
                        }
                        // test size above then fetch
                        object elem = _Next();
                        return elem;
                }
                
                override protected object Dup(object el) 
                {
                        return adaptor.DupTree(el);
                }
        }
}
#elif DOTNET2
namespace Antlr.Runtime.Tree {
        using System;
        using System.Collections.Generic;
        using SpecializingType = System.Object;

#warning Check, if RewriteRuleSubtreeStream can be changed to take advantage of something more specific than object.
        public class RewriteRuleSubtreeStream : RewriteRuleElementStream<SpecializingType> {

                #region private delegate object ProcessHandler(object o)
                private delegate object ProcessHandler(object o);
                #endregion

                public RewriteRuleSubtreeStream(ITreeAdaptor adaptor, string elementDescription)
                        : base(adaptor, elementDescription) {
                }

                public RewriteRuleSubtreeStream(
                        ITreeAdaptor adaptor,
                        string elementDescription,
                        SpecializingType oneElement
                ) : base(adaptor, elementDescription, oneElement) {
                }

                public RewriteRuleSubtreeStream(
                        ITreeAdaptor adaptor,
                        string elementDescription,
                        IList<SpecializingType> elements
                ) : base(adaptor, elementDescription, elements) {
                }

                [Obsolete("This constructor is for internal use only and might be phased out soon. Use instead the one with IList<T>.")]
                public RewriteRuleSubtreeStream(
                        ITreeAdaptor adaptor,
                        string elementDescription,
                        System.Collections.IList elements
                ) : base(adaptor, elementDescription, elements) {
                }

                public object NextNode() {
                        // if necessary, dup (at most a single node since this is for making root nodes).
                        return FetchObject(delegate(object o) { return adaptor.DupNode(o); });
                }

                #region private object FetchObject(ProcessHandler ph)
                private object FetchObject(ProcessHandler ph) {
                        if (RequiresDuplication()) {
                                // process the object
                                return ph(_Next());
                        }
                        // test above then fetch
                        return _Next();
                }
                #endregion

                private bool RequiresDuplication() {
                        int size = Size();
                        // if dirty or if out of elements and size is 1
                        return dirty || ((cursor >= size) && (size == 1));
                }

                #region public override object NextTree()
                public override object NextTree() {
                        // if out of elements and size is 1, dup
                        return FetchObject(delegate(object o) { return Dup(o); });
                }
                #endregion


                private SpecializingType Dup(SpecializingType el) {
                        return adaptor.DupTree(el);
                }
        }
}
#endif

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