/Users/parrt/antlr/code/antlr/main/runtime/CSharp/Sources/Antlr3.Runtime/Antlr.Runtime.Tree/RewriteRuleElementStream.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,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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;
        using ArrayList         = System.Collections.ArrayList;
        using IToken            = Antlr.Runtime.IToken;
        using CommonToken       = Antlr.Runtime.CommonToken;
        
        public abstract class RewriteRuleElementStream
        {
                protected int cursor = 0;

                protected object singleElement;

                protected IList elements;

                protected bool dirty = false;

                protected string elementDescription;
                protected ITreeAdaptor adaptor;

                public RewriteRuleElementStream(ITreeAdaptor adaptor, string elementDescription) 
                {
                        this.elementDescription = elementDescription;
                        this.adaptor = adaptor;
                }

                public RewriteRuleElementStream(ITreeAdaptor adaptor, string elementDescription, object oneElement)
                        : this(adaptor, elementDescription)
                {
                        Add(oneElement);
                }

                public RewriteRuleElementStream(ITreeAdaptor adaptor, string elementDescription, IList elements)
                        : this(adaptor, elementDescription)
                {
                        this.singleElement = null;
                        this.elements = elements;
                }

                public void Add(object el) 
                {
                        if ( el == null ) 
                        {
                                return;
                        }
                        if ( elements != null ) 
                        { // if in list, just add
                                elements.Add(el);
                                return;
                        }
                        if ( singleElement == null ) 
                        { // no elements yet, track w/o list
                                singleElement = el;
                                return;
                        }
                        // adding 2nd element, move to list
                        elements = new ArrayList(5);
                        elements.Add(singleElement);
                        singleElement = null;
                        elements.Add(el);
                }

                public virtual void Reset()
                {
                        cursor = 0;
                        dirty = true;
                }

                public bool HasNext()
                {
                        return ( ((singleElement != null) && (cursor < 1)) ||
                                  ((elements != null) && (cursor < elements.Count)) );
                }

                public virtual object NextTree()
                {
                        int size = Size();
                        if ( dirty || ((cursor >= size) && (size == 1)) )
                        {
                                // if out of elements and size is 1, dup
                                return Dup(_Next());
                        }
                        // test size above then fetch
                        return _Next();
                }

                protected object _Next() 
                {
                        int size = Size();
                        if ( size == 0 ) 
                        {
                                throw new RewriteEmptyStreamException(elementDescription);
                        }
                        if ( cursor >= size ) 
                        { // out of elements?
                                if ( size == 1 ) 
                                {  // if size is 1, it's ok; return and we'll dup 
                                        return ToTree(singleElement);
                                }
                                // out of elements and size was not 1, so we can't dup
                                throw new RewriteCardinalityException(elementDescription);
                        }
                        // we have elements
                        if ( singleElement != null ) 
                        {
                                cursor++; // move cursor even for single element list
                                return ToTree(singleElement);
                        }
                        // must have more than one in list, pull from elements
                        return ToTree(elements[cursor++]);
                }

                protected abstract object Dup(object el);

                protected virtual object ToTree(object el) 
                {
                        return el;
                }

#warning Size() should be converted into a property named Count.
                public int Size() 
                {
                        if (singleElement != null) {
                                return 1;
                        }
                        if (elements != null) {
                                return elements.Count;
                        }
                        return 0;
                }

                public string Description
                {
                        get { return elementDescription; }
                }
        }
}
#elif DOTNET2
namespace Antlr.Runtime.Tree {
        using System;
        using System.Collections.Generic;
        using IToken = Antlr.Runtime.IToken;
        using CommonToken = Antlr.Runtime.CommonToken;

        public abstract class RewriteRuleElementStream<T> {
                protected int cursor = 0;

                protected T singleElement;

                protected IList<T> elements;

                protected bool dirty = false;

                protected string elementDescription;
                protected ITreeAdaptor adaptor;

                public RewriteRuleElementStream(ITreeAdaptor adaptor, string elementDescription) {
                        this.elementDescription = elementDescription;
                        this.adaptor = adaptor;
                }

                public RewriteRuleElementStream(
                        ITreeAdaptor adaptor,
                        string elementDescription,
                        T oneElement
                )
                        : this(adaptor, elementDescription) {
                        Add(oneElement);
                }

                public RewriteRuleElementStream(
                        ITreeAdaptor adaptor,
                    string elementDescription,
                    IList<T> elements
                )
                        : this(adaptor, elementDescription) {
                        this.singleElement = default(T);
                        this.elements = elements;
                }

                [Obsolete("This constructor is for internal use only and might be phased out soon. Use instead the one with IList<T>.")]
                public RewriteRuleElementStream(
                        ITreeAdaptor adaptor,
                        string elementDescription,
                    System.Collections.IList elements
                )
                        : this(adaptor, elementDescription) {
                        this.singleElement = default(T);
                        this.elements = new List<T>();
                        if (elements != null) {
                                foreach (T t in elements) {
                                        this.elements.Add(t);
                                }
                        }
                }

                public void Add(T el) {
                        if (el == null) {
                                return;
                        }
                        if (elements != null) { // if in list, just add
                                elements.Add(el);
                                return;
                        }
                        if (singleElement == null) { // no elements yet, track w/o list
                                singleElement = el;
                                return;
                        }
                        // adding 2nd element, move to list
                        elements = new List<T>(5);
                        elements.Add(singleElement);
                        singleElement = default(T);
                        elements.Add(el);
                }

                public virtual void Reset() {
                        cursor = 0;
                        dirty = true;
                }

                public bool HasNext() {
                        return (((singleElement != null) && (cursor < 1)) ||
                                  ((elements != null) && (cursor < elements.Count)));
                }

                public virtual object NextTree() {
                        return _Next();
                }

                protected object _Next() {
                        int size = Size();
                        if (size == 0) {
                                throw new RewriteEmptyStreamException(elementDescription);
                        }
                        if (cursor >= size) { // out of elements?
                                if (size == 1) {  // if size is 1, it's ok; return and we'll dup 
                                        return ToTree(singleElement);
                                }
                                // out of elements and size was not 1, so we can't dup
                                throw new RewriteCardinalityException(elementDescription);
                        }
                        // we have elements
                        if (singleElement != null) {
                                cursor++; // move cursor even for single element list
                                return ToTree(singleElement);
                        }
                        // must have more than one in list, pull from elements
                        return ToTree(elements[cursor++]);
                }

                protected virtual object ToTree(T el) {
                        return el;
                }

#warning Size() should be converted into a property named Count.
                public int Size() {
                        if (singleElement != null) {
                                return 1;
                        }
                        if (elements != null) {
                                return elements.Count;
                        }
                        return 0;
                }

                public string Description {
                        get { return elementDescription; }
                }
        }
}
#endif

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