externalcode.h

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#ifndef EXTERNALCODE_H_INCLUDED_
#define EXTERNALCODE_H_INCLUDED_

#include "globalincs/pstypes.h"

/* We must have windows.h anywhere SCP_ExternalCode is used under windows */
#ifdef _WIN32
#include <windows.h>
#endif

/* This class loads external libraries for FSO use.
 * Different platforms have different ways of doing this, so use your ifdefs!
 */
class SCP_ExternalCode
{
public:
        SCP_ExternalCode( )
#ifdef _WIN32
                : m_dll( NULL )
#endif
        {
        }

        virtual ~SCP_ExternalCode( )
        {
#ifdef _WIN32
                if ( m_dll )
                        ::FreeLibrary( m_dll );
#endif
        }

protected:
        BOOL LoadExternal( const char* externlib )
        {
                if ( !externlib )
                        return FALSE;
                
#ifdef _WIN32
                m_dll = ::LoadLibrary( externlib );
                
                if ( m_dll )
                        return TRUE;
#endif

                return FALSE;
        }

        void* LoadFunction( const char* functionname )
        {
#ifdef _WIN32
                if ( m_dll != NULL && functionname != NULL )
                        return ::GetProcAddress( m_dll, functionname );
#endif
                return NULL;
        }
private:
#ifdef _WIN32
        HMODULE m_dll;
#endif
};

/* These are available if you're compiling an external DLL
 * So far we have trackir, and speech is on the way
 */
#ifdef _WIN32
#       define SCP_EXT_CALLCONV __cdecl
#       ifdef SCPDLL_EXTERNAL_LIB
#               define SCPDLL_EXTERNAL __declspec( dllexport )
#       else
#               define SCPDLL_EXTERNAL __declspec( dllimport )
#       endif
/* Must be in a CPP file in your DLL code
 * If you want to write your own, you shouldn't.
 */
#       define SCPDLL_DLLMAIN( ) \
                SCP_EXTERN_C BOOL APIENTRY DllMain( HANDLE, DWORD, LPVOID ) { return TRUE; }
#else
#       define SCP_EXT_CALLCONV
#       define SCPDLL_EXTERNAL
#       define SCPDLL_DLLMAIN( )
#endif

#ifdef __cplusplus
#       define SCP_EXTERN_C extern "C"
#else
#       define SCP_EXTERN_C
#endif

/* Version information */
typedef struct _SCPDLL_Version
{
        int major;
        int minor;
        int patch;
} SCPDLL_Version;

typedef int ( SCP_EXT_CALLCONV *SCPDLL_PFVERSION )( SCPDLL_Version* );

/* Must be in a CPP file in your DLL code */
#define SCPDLL_VERSION_FUNCTION( Major, Minor, Patch ) \
        SCP_EXTERN_C int SCPDLL_EXTERNAL SCPDLL_GetVersion( SCPDLL_Version* v ) { \
                if ( !v ) return -1;\
                v->major = Major; v->minor = Minor; v->patch = Patch;\
                return 0; }

#endif /* EXTERNALCODE_H_INCLUDED_ */