使用带有不明确重载错误的ogre3d的自定义流/流buf

当前正在尝试使用ogre和stl创建XML系统。作为概念的证明,我们试图让它将XML文件的内容输出到日志文件中。遗憾的是,我们当前的代码无法编译,我们也不知道为什么。相关代码如下:

这里是一个继承自的流类,用于简化自定义streambuf的管理。它存在的主要原因是删除了它的析构函数中的自定义streambuf。

class ResourceInputStream : public std::istream
{
    private:
        internal::OgreDataStreamBuf* OgreBuffer;
        ResourceManager* Manager;

        /// @internal
        /// @brief Called by the constructors to actually construct this class
        /// @param InputBuffer A pointer to an internal::OgreDataStreamBuf. A buffer to read from the disk access subsystem (which happens to be part of Ogre). This Stream will assume ownership of this buffer and will handle deleting it.
        /// @param ResourceManager_ Currently unused, future functionality may tuse this.
        void Construct(std::streambuf *InputBuffer, ResourceManager* ResourceManager_);

    protected:

    public:
        /// @brief Descriptive Constructor
        /// @param InputBuffer A pointer to an internal::OgreDataStreamBuf. A buffer to read from the disk access subsystem (which happens to be part of Ogre). This Stream will assume ownership of this buffer and will handle deleting it.
        /// @param ResourceManager_ Currently unused, future functionality may tuse this.
        /// @warning Do not delete the InputBuffer you pass in, this class will assume owner ship and delete it on it's own
        ResourceInputStream(std::streambuf *InputBuffer, ResourceManager* ResourceManager_) :
            std::istream(InputBuffer)
            { this->Construct(InputBuffer, ResourceManager_); }

        /// @brief Tears down the Stream, and Delete the Buffer Passed in.
        virtual ~ResourceInputStream();

};

下面是自定义streambuf类的定义。它使用ogredatastreambuf读取由ogre资源库管理的压缩文件:

 class OgreDataStreamBuf : public std::streambuf
        {
            protected:
                /// @brief a shard_ptr to the internal Ogre Datastream
                Ogre::DataStreamPtr OgreStream;

            public:

                /// @brief constructor
                /// @param Datum A pointer to the Ogre Datastream that this stream will use
                OgreDataStreamBuf(const Ogre::DataStreamPtr& Datum) : OgreStream(Datum)
                {
                    #ifdef PHYSDEBUG
                    World::GetWorldPointer()->Log("Entering/Exiting OgreDataStreamBuf Constructor");
                    #endif
                }

                /// @brief Should get the amount of characters left in the sequence
                /// @returns -1 if no estimate could be made, other wise this returns an estimate of the amount of bytes in the buffer
                std::streamsize showmanyc();

                /// @brief Gets a sequence of characters
                /// @param s a Pointer to where the characters should go
                /// @param n How many characters
                /// @return This returns the amount of characters retrieved
                std::streamsize xsgetn(char* s, std::streamsize n);

                /// @brief puts a sequence of characters in
                /// @param s a Pointer to the characters
                /// @param n How many characters
                /// @return This returns the amount of characters inserted
                /// @detail currently unimplimented
                std::streamsize xsputn(const char_type*, std::streamsize n);
        };
    }

下面是一段试图使用这个流类的代码。世界日志流是一个std::stringstream。

ResourceInputStream* XMLptr = TheWorld->GetResourceManager()->GetResourceStream("test.xml");
std::stringstream XMLStringStream;
(*XMLptr) >> XMLStringStream;
String ShouldHaveXML(XMLStringStream.str());
TheWorld->LogStream << "ShouldHaveXML: " << ShouldHaveXML << endl << "End XML Logging" <<endl;
TheWorld->Log("Delete XML Stream");
delete XMLptr;

尝试编译会产生此错误:

error: ambiguous overload for 'operator>>' in '* XMLptr >> XMLStringStream'

我研究过这个错误,唯一能发现的就是…这是由于某些被声明为常量的东西不应该这样做。据我们所知,我们的代码不是这样的。所以我对这件事的发生原因,或者如何着手解决这个问题感到茫然。任何见解都将受到极大的赞赏。