xslibraryloader.h

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/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          http://www.mrpt.org/                          |
   |                                                                        |
   | Copyright (c) 2005-2017, Individual contributors, see AUTHORS file     |
   | See: http://www.mrpt.org/Authors - All rights reserved.                |
   | Released under BSD License. See details in http://www.mrpt.org/License |
   +------------------------------------------------------------------------+ */
#ifndef XSLIBRARYLOADER_H
#define XSLIBRARYLOADER_H

#include "xstypesconfig.h"
#include "xsstring.h"

struct XsLibraryLoader;

#ifdef __cplusplus
extern "C" {
#else
#define XSLIBRARYLOADER_INITIALIZER \
        {                               \
                nullptr                     \
        }
typedef struct XsLibraryLoader XsLibraryLoader;
#endif

XSTYPES_DLL_API int XsLibraryLoader_load(
        XsLibraryLoader* thisp, const XsString* libraryName);
XSTYPES_DLL_API void* XsLibraryLoader_resolve(
        const XsLibraryLoader* thisp, const char* functionName);
XSTYPES_DLL_API int XsLibraryLoader_unload(XsLibraryLoader* thisp);
XSTYPES_DLL_API int XsLibraryLoader_isLoaded(const XsLibraryLoader* thisp);
XSTYPES_DLL_API void XsLibraryLoader_getErrorString(XsString* error);

#ifdef __cplusplus
}
#endif

/*! \brief The Xsens dynamic library loader base class
*/
struct XsLibraryLoader
{
#ifdef __cplusplus
   public:
        /*! \brief Create a library loader */
        inline XsLibraryLoader() : m_handle(nullptr)
        {
                // avoid compiler warnings about
                // an unused handle. It is used in the c implementations
                (void)m_handle;
        }

        /*! \brief Destroy a library loader */
        inline ~XsLibraryLoader() { unload(); }
        /*! \brief Load the library
          \param[in] libraryName the name of the library to load
          \return true if the library could be loaded, false otherwise
        */
        inline bool load(const XsString& libraryName)
        {
                return XsLibraryLoader_load(this, &libraryName) != 0;
        }

        /*! \brief Return true if a library has been loaded

          \return true if a library has been loaded, false otherwise
        */
        inline bool isLoaded() const { return XsLibraryLoader_isLoaded(this) != 0; }
        /*! \brief Resolve a function from the library

          \param[in] functionName the name of the function to resolve
          \return a pointer to the resolved function, nullptr if nothing could be
          resolved
        */
        inline void* resolve(const char* functionName) const
        {
                return XsLibraryLoader_resolve(this, functionName);
        }

        /*! \brief Unload the loaded library
        */
        inline void unload() throw() { XsLibraryLoader_unload(this); }
        /*! \brief Return a string describing the error that occurred

          Use this function after a function returned with an error to
          receive some extra information about what went wrong.

          \returns a string describing the error that occurred
        */
        inline static XsString errorString()
        {
                XsString rv;
                XsLibraryLoader_getErrorString(&rv);
                return rv;
        }

   private:
#endif
        void* m_handle;
};

#endif  // XSLIBRARYLOADER_H