xslibraryloader.h

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/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          https://www.mrpt.org/                         |
   |                                                                        |
   | Copyright (c) 2005-2019, Individual contributors, see AUTHORS file     |
   | See: https://www.mrpt.org/Authors - All rights reserved.               |
   | Released under BSD License. See: https://www.mrpt.org/License          |
   +------------------------------------------------------------------------+ */
#ifndef XSLIBRARYLOADER_H
#define XSLIBRARYLOADER_H

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