Wrap dll functions more simply

* decompress.c, gnutls.c, image.c, xml.c:
If WINDOWSNT, use '#define FOO fn_FOO' to wrap dll functions,
rather than the inverse when not WINDOWSNT.  This isolates the
fn_* business into the WINDOWSNT-specific section of the code,
which makes it easier to maintain the generic code.
* decompress.c (DEF_ZLIB_FN, LOAD_ZLIB_FN):
* gnutls.c (DEF_GNUTLS_FN, LOAD_GNUTLS_FN):
* image.c (DEF_IMGLIB_FN, LOAD_IMGLIB_FN):
* xml.c (DEF_XML2_FN, LOAD_XML2_FN):
Remove.  All uses replaced by DEF_DLL_FN.
* w32.h (DEF_DLL_FN, LOAD_DLL_FN): New macros.

1 files changed, 19 insertions, 32 deletions

diff --git a/src/decompress.c b/src/decompress.c
index 24ce852245c..f86aa6facbf 100644
--- a/src/decompress.c
+++ b/src/decompress.c
@@ -31,26 +31,14 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 static Lisp_Object Qzlib_dll;
 
 #ifdef WINDOWSNT
-#include <windows.h>
-#include "w32.h"
+# include <windows.h>
+# include "w32.h"
 
-/* Macro for defining functions that will be loaded from the zlib DLL.  */
-#define DEF_ZLIB_FN(rettype,func,args) static rettype (FAR CDECL *fn_##func)args
-
-/* Macro for loading zlib functions from the library.  */
-#define LOAD_ZLIB_FN(lib,func) {                                        \
-    fn_##func = (void *) GetProcAddress (lib, #func);                   \
-    if (!fn_##func) return false;                                       \
-  }
-
-DEF_ZLIB_FN (int, inflateInit2_,
-             (z_streamp strm, int  windowBits, const char *version, int stream_size));
-
-DEF_ZLIB_FN (int, inflate,
-             (z_streamp strm, int flush));
-
-DEF_ZLIB_FN (int, inflateEnd,
-             (z_streamp strm));
+DEF_DLL_FN (int, inflateInit2_,
+            (z_streamp strm, int windowBits, const char *version,
+             int stream_size));
+DEF_DLL_FN (int, inflate, (z_streamp strm, int flush));
+DEF_DLL_FN (int, inflateEnd, (z_streamp strm));
 
 static bool zlib_initialized;
 
@@ -62,20 +50,19 @@ init_zlib_functions (void)
   if (!library)
     return false;
 
-  LOAD_ZLIB_FN (library, inflateInit2_);
-  LOAD_ZLIB_FN (library, inflate);
-  LOAD_ZLIB_FN (library, inflateEnd);
+  LOAD_DLL_FN (library, inflateInit2_);
+  LOAD_DLL_FN (library, inflate);
+  LOAD_DLL_FN (library, inflateEnd);
   return true;
 }
 
-#define fn_inflateInit2(strm, windowBits) \
-        fn_inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream))
-
-#else /* !WINDOWSNT */
+# undef inflate
+# undef inflateEnd
+# undef inflateInit2_
 
-#define fn_inflateInit2         inflateInit2
-#define fn_inflate              inflate
-#define fn_inflateEnd           inflateEnd
+# define inflate fn_inflate
+# define inflateEnd fn_inflateEnd
+# define inflateInit2_ fn_inflateInit2_
 
 #endif  /* WINDOWSNT */
 
@@ -90,7 +77,7 @@ static void
 unwind_decompress (void *ddata)
 {
   struct decompress_unwind_data *data = ddata;
-  fn_inflateEnd (data->stream);
+  inflateEnd (data->stream);
 
   /* Delete any uncompressed data already inserted on error.  */
   if (data->start)
@@ -167,7 +154,7 @@ This function can be called only in unibyte buffers.  */)
 
   /* The magic number 32 apparently means "autodetect both the gzip and
      zlib formats" according to zlib.h.  */
-  if (fn_inflateInit2 (&stream, MAX_WBITS + 32) != Z_OK)
+  if (inflateInit2 (&stream, MAX_WBITS + 32) != Z_OK)
     return Qnil;
 
   unwind_data.start = iend;
@@ -197,7 +184,7 @@ This function can be called only in unibyte buffers.  */)
       stream.avail_in = avail_in;
       stream.next_out = GPT_ADDR;
       stream.avail_out = avail_out;
-      inflate_status = fn_inflate (&stream, Z_NO_FLUSH);
+      inflate_status = inflate (&stream, Z_NO_FLUSH);
       pos_byte += avail_in - stream.avail_in;
       decompressed = avail_out - stream.avail_out;
       insert_from_gap (decompressed, decompressed, 0);