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

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/*
[The "BSD licence"]
Copyright (c) 2007-2008 Johannes Luber
Copyright (c) 2005-2007 Kunle Odutola
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
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   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,
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THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/


namespace Antlr.Runtime.Tree
{
        using System;
        using IDictionary = System.Collections.IDictionary;
        using Hashtable = System.Collections.Hashtable;
        using IToken = Antlr.Runtime.IToken;

        public abstract class BaseTreeAdaptor : ITreeAdaptor
        {
                protected IDictionary treeToUniqueIDMap;

                protected int uniqueNodeID = 1;

                public virtual object GetNilNode()
                {
                        return Create(null);
                }
                
                public virtual object ErrorNode(ITokenStream input, IToken start, IToken stop,
                                                                RecognitionException e)
                {
                        CommonErrorNode t = new CommonErrorNode(input, start, stop, e);
                        //System.out.println("returning error node '"+t+"' @index="+input.index());
                        return t;
                }
        
                public virtual bool IsNil(object tree) 
                {
                        return ((ITree)tree).IsNil;
                }

                public virtual object DupTree(object tree)
                {
                        return DupTree(tree, null);
                }

                public virtual object DupTree(object t, object parent)
                {
                        if (t == null)
                        {
                                return null;
                        }
                        object newTree = DupNode(t);
                        // ensure new subtree root has parent/child index set
                        SetChildIndex(newTree, GetChildIndex(t)); // same index in new tree
                        SetParent(newTree, parent);
                        int n = GetChildCount(t);
                        for (int i = 0; i < n; i++)
                        {
                                object child = GetChild(t, i);
                                object newSubTree = DupTree(child, t);
                                AddChild(newTree, newSubTree);
                        }
                        return newTree;
                }

                public virtual void  AddChild(object t, object child)
                {
                        if ((t != null) && (child != null))
                        {
                                ((ITree) t).AddChild((ITree) child);
                        }
                }
                
                public virtual object BecomeRoot(object newRoot, object oldRoot)
                {
                        ITree newRootTree = (ITree) newRoot;
                        ITree oldRootTree = (ITree) oldRoot;
                        if (oldRoot == null)
                        {
                                return newRoot;
                        }
                        // handle ^(nil real-node)
                        if (newRootTree.IsNil)
                        {
                    int nc = newRootTree.ChildCount;
                    if ( nc==1 ) newRootTree = (ITree)newRootTree.GetChild(0);
                    else if ( nc >1 ) {
                                        throw new SystemException("more than one node as root (TODO: make exception hierarchy)");
                                }
                        }
                        // add oldRoot to newRoot; AddChild takes care of case where oldRoot
                        // is a flat list (i.e., nil-rooted tree).  All children of oldRoot
                        // are added to newRoot.
                        newRootTree.AddChild(oldRootTree);
                        return newRootTree;
                }

                public virtual object RulePostProcessing(object root)
                {
                        ITree r = (ITree) root;
                        if (r != null && r.IsNil)
                        {
                                if (r.ChildCount == 0)
                                {
                                        r = null;
                                }
                                else if (r.ChildCount == 1)
                                {
                                        r = (ITree)r.GetChild(0);
                                        // whoever invokes rule will set parent and child index
                                        r.Parent = null;
                                        r.ChildIndex = -1;
                                }
                        }
                        return r;
                }
                
                public virtual object BecomeRoot(IToken newRoot, object oldRoot)
                {
                        return BecomeRoot(Create(newRoot), oldRoot);
                }
                
                public virtual object Create(int tokenType, IToken fromToken)
                {
                        fromToken = CreateToken(fromToken);
                        fromToken.Type = tokenType;
                        ITree t = (ITree) Create(fromToken);
                        return t;
                }
                
                public virtual object Create(int tokenType, IToken fromToken, string text)
                {
                        fromToken = CreateToken(fromToken);
                        fromToken.Type = tokenType;
                        fromToken.Text = text;
                        ITree t = (ITree) Create(fromToken);
                        return t;
                }
                
                public virtual object Create(int tokenType, string text)
                {
                        IToken fromToken = CreateToken(tokenType, text);
                        ITree t = (ITree) Create(fromToken);
                        return t;
                }
                
                public virtual int GetNodeType(object t)
                {
                        int generatedAux = ((ITree) t).Type;
                        return 0;
                }

                public virtual void SetNodeType(object t, int type)
                {
                        throw new NotImplementedException("don't know enough about Tree node");
                }

                public virtual string GetNodeText(object t)
                {
                        return ((ITree)t).Text;
                }

                public virtual void SetNodeText(object t, string text)
                {
                        throw new NotImplementedException("don't know enough about Tree node");
                }
                
                public virtual object GetChild(object t, int i)
                {
                        return ((ITree)t).GetChild(i);
                }

                public virtual void SetChild(object t, int i, object child)
                {
                        ((ITree)t).SetChild(i, (ITree)child);
                }

                public virtual object DeleteChild(object t, int i)
                {
                        return ((ITree)t).DeleteChild(i);
                }

                public virtual int GetChildCount(object t)
                {
                        return ((ITree)t).ChildCount;
                        
                }

                public abstract object DupNode(object param1);
                public abstract object Create(IToken param1);
                public abstract void  SetTokenBoundaries(object param1, IToken param2, IToken param3);
                public abstract int GetTokenStartIndex(object t);
                public abstract int GetTokenStopIndex(object t);
                public abstract IToken GetToken(object treeNode);

                public int GetUniqueID(object node)
                {
                        if (treeToUniqueIDMap == null)
                        {
                                treeToUniqueIDMap = new Hashtable();
                        }
                        object prevIdObj = treeToUniqueIDMap[node];
                        if (prevIdObj != null)
                        {
                                return (int) prevIdObj;
                        }
                        int ID = uniqueNodeID;
                        treeToUniqueIDMap[node] = ID;
                        uniqueNodeID++;
                        return ID;

                        //return node.GetHashCode();
                        //return System.Runtime.CompilerServices.RuntimeHelpers.GetHashCode(node);
                }

                public abstract IToken CreateToken(int tokenType, string text);

                public abstract IToken CreateToken(IToken fromToken);

                public abstract object GetParent(object t);
                public abstract void SetParent(object t, object parent);

                public abstract int GetChildIndex(object t);
                public abstract void SetChildIndex(object t, int index);

                public abstract void ReplaceChildren(object parent, int startChildIndex, int stopChildIndex, object t);
        }
}

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