dlls/ddraw/ddcomimpl.h

   1 /* A few helpful macros for implementing COM objects.
   2  *
   3  * Copyright 2000 TransGaming Technologies Inc.
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2.1 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General Public
  16  * License along with this library; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  18  */
  19
  20 #ifndef _DDCOMIMPL_H_
  21 #define _DDCOMIMPL_H_
  22
  23 #include <stddef.h>
  24
  25 /* Generates the name for a vtable pointer for a given interface. */
  26 /* The canonical name for a single interface is "lpVtbl". */
  27 #define ICOM_VFIELD_MULTI_NAME2(iface) ITF_##iface
  28 #define ICOM_VFIELD_MULTI_NAME(iface) ICOM_VFIELD_MULTI_NAME2(iface)
  29
  30 /* Declares a vtable pointer field in an implementation. */
  31 #define ICOM_VFIELD_MULTI(iface) \
  32         iface ICOM_VFIELD_MULTI_NAME(iface)
  33
  34 /* Returns the offset of a vtable pointer within an implementation object. */
  35 #define ICOM_VFIELD_OFFSET(impltype, iface) \
  36         offsetof(impltype, ICOM_VFIELD_MULTI_NAME(iface))
  37
  38 /* Given an interface pointer, returns the implementation pointer. */
  39 #define ICOM_OBJECT(impltype, ifacename, ifaceptr)              \
  40         (impltype*)((ifaceptr) == NULL ? NULL                   \
  41                   : (char*)(ifaceptr) - ICOM_VFIELD_OFFSET(impltype,ifacename))
  42
  43 #define ICOM_THIS_FROM(impltype, ifacename, ifaceptr) \
  44         impltype* This = ICOM_OBJECT(impltype, ifacename, ifaceptr)
  45
  46 /* Given an object and interface name, returns a pointer to that interface. */
  47 #define ICOM_INTERFACE(implobj, iface) \
  48         (&((implobj)->ICOM_VFIELD_MULTI_NAME(iface)))
  49
  50 #define ICOM_INIT_INTERFACE(implobj, ifacename, vtblname) \
  51         do { \
  52           (implobj)->ICOM_VFIELD_MULTI_NAME(ifacename).lpVtbl = &(vtblname); \
  53         } while (0)
  54
  55 #define COM_INTERFACE_CAST(impltype, ifnamefrom, ifnameto, ifaceptr)    \
  56         ICOM_INTERFACE(ICOM_OBJECT(impltype, ifnamefrom, ifaceptr), ifnameto)
  57
  58 #endif /* _DDCOMIMPL_H_ */