TypeSafeGenericPointer.hpp

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/* ImLib3D
 * Copyright (c) 2001, ULP-IPB Strasbourg.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or (at
 * your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#ifndef _TypeSafeGenericPointer_hpp
#define _TypeSafeGenericPointer_hpp

#include<ImLib3D/CppTools.hpp>

class TypeSafeGenericPointer
{
    void *ptr;
    const char *typeinfoName;
    map<string,void *> alternateCasts;
public:
    string DemangledTypeName(){return TypeNameParser(typeinfoName);}
    string TypeName(){return typeinfoName;}
    bool IsSet(){return string(typeinfoName)!=string("");}
    void Clear(){ptr=NULL;typeinfoName="";alternateCasts.clear();}
    template<class T>
    T Get()
    {
        if(!IsSet()){ThrowError("TypeSafeGenericPointer::Get Trying to read value unset pointer");}
        string castTypeName=typeid(T).name();
        if(castTypeName!=typeinfoName)
        {
            // normal cast failed.. try alternate casts
            if(alternateCasts.find(castTypeName)!=alternateCasts.end())
            {
                return (T)alternateCasts[castTypeName];
            }
            string alt;
            for(map<string,void *>::iterator p=alternateCasts.begin();p!=alternateCasts.end();++p)
            {
                alt+=TypeNameParser((*p).first)+",";
            }
            ThrowError("TypeSafeGenericPointer::Get: Attempted to use pointer as:\"%s\". Originally,  pointer was stored as:\"%s\": available alternate casts where:\"%s\"",
                     TypeNameParser(castTypeName).c_str(),
                     DemangledTypeName().c_str(),
                     alt.c_str());
        }
        return (T)ptr;
    }
    template<class T>
    void Set(T _ptr)
    {
        typeinfoName=typeid(T).name();
        ptr=(void*)_ptr;
    }

    template<class OriginalType,class AlternateType>
    void AddAlternateCast()
    {
        alternateCasts[typeid(AlternateType).name()]=(void*)(AlternateType)(OriginalType)ptr;
    }


    template<class T>
    TypeSafeGenericPointer(T _ptr)
    {
        Set(_ptr);
    }
    TypeSafeGenericPointer &operator=(const TypeSafeGenericPointer &other)
    {
        ptr=other.ptr;
        typeinfoName=other.typeinfoName;
        alternateCasts=other.alternateCasts;
        return *this;
    }
    TypeSafeGenericPointer(const TypeSafeGenericPointer &other)
    {
        ptr=other.ptr;
        typeinfoName=other.typeinfoName;
        alternateCasts=other.alternateCasts;
    }
    TypeSafeGenericPointer():ptr(NULL),typeinfoName("")
    {
    }
};


#endif // _TypeSafeGenericPointer_hpp

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