user: Separate Get/SetWindowLong16 implementation from the 32-bit one.

dlls/user/win.c

@@ -1888,24 +1888,6 @@ static LONG_PTR WIN_GetWindowLong( HWND hwnd, INT offset, WINDOWPROCTYPE type )
     {
         if (offset > (int)(wndPtr->cbWndExtra - sizeof(LONG)))
         {
-          /*
-            * Some programs try to access last element from 16 bit
-            * code using illegal offset value. Hopefully this is
-            * what those programs really expect.
-            */
-           if (type == WIN_PROC_16 &&
-               wndPtr->cbWndExtra >= 4 &&
-               offset == wndPtr->cbWndExtra - sizeof(WORD))
-           {
-               INT offset2 = wndPtr->cbWndExtra - sizeof(LONG);
-
-               ERR( "- replaced invalid offset %d with %d\n",
-                    offset, offset2 );
-
-                retvalue = *(LONG_PTR *)(((char *)wndPtr->wExtra) + offset2);
-                WIN_ReleasePtr( wndPtr );
-                return retvalue;
-            }
             WARN("Invalid offset %d\n", offset );
             WIN_ReleasePtr( wndPtr );
             SetLastError( ERROR_INVALID_INDEX );
@@ -2144,7 +2126,47 @@ static LONG_PTR WIN_SetWindowLong( HWND hwnd, INT offset, LONG_PTR newval,
  */
 LONG WINAPI GetWindowLong16( HWND16 hwnd, INT16 offset )
 {
-    return WIN_GetWindowLong( WIN_Handle32(hwnd), offset, WIN_PROC_16 );
+    WND *wndPtr;
+    LONG_PTR retvalue;
+    BOOL is_winproc = (offset == GWLP_WNDPROC);
+
+    if (offset >= 0)
+    {
+        if (!(wndPtr = WIN_GetPtr( WIN_Handle32(hwnd) )))
+        {
+            SetLastError( ERROR_INVALID_WINDOW_HANDLE );
+            return 0;
+        }
+        if (wndPtr != WND_OTHER_PROCESS && wndPtr != WND_DESKTOP)
+        {
+            if (offset > (int)(wndPtr->cbWndExtra - sizeof(LONG)))
+            {
+                /*
+                 * Some programs try to access last element from 16 bit
+                 * code using illegal offset value. Hopefully this is
+                 * what those programs really expect.
+                 */
+                if (wndPtr->cbWndExtra >= 4 && offset == wndPtr->cbWndExtra - sizeof(WORD))
+                {
+                    INT offset2 = wndPtr->cbWndExtra - sizeof(LONG);
+                    ERR( "- replaced invalid offset %d with %d\n", offset, offset2 );
+                    offset = offset2;
+                }
+                else
+                {
+                    WARN("Invalid offset %d\n", offset );
+                    WIN_ReleasePtr( wndPtr );
+                    SetLastError( ERROR_INVALID_INDEX );
+                    return 0;
+                }
+            }
+            is_winproc = ((offset == DWLP_DLGPROC) && (wndPtr->flags & WIN_ISDIALOG));
+            WIN_ReleasePtr( wndPtr );
+        }
+    }
+    retvalue = GetWindowLongA( WIN_Handle32(hwnd), offset );
+    if (is_winproc) retvalue = (LONG_PTR)WINPROC_GetProc( (WNDPROC)retvalue, WIN_PROC_16 );
+    return retvalue;
 }
 
 
@@ -2171,7 +2193,31 @@ LONG WINAPI GetWindowLongW( HWND hwnd, INT offset )
  */
 LONG WINAPI SetWindowLong16( HWND16 hwnd, INT16 offset, LONG newval )
 {
-    return WIN_SetWindowLong( WIN_Handle32(hwnd), offset, newval, WIN_PROC_16 );
+    WND *wndPtr;
+    BOOL is_winproc = (offset == GWLP_WNDPROC);
+
+    if (offset == DWLP_DLGPROC)
+    {
+        if (!(wndPtr = WIN_GetPtr( WIN_Handle32(hwnd) )))
+        {
+            SetLastError( ERROR_INVALID_WINDOW_HANDLE );
+            return 0;
+        }
+        if (wndPtr != WND_OTHER_PROCESS && wndPtr != WND_DESKTOP)
+        {
+            is_winproc = ((wndPtr->cbWndExtra - sizeof(LONG_PTR) >= DWLP_DLGPROC) &&
+                          (wndPtr->flags & WIN_ISDIALOG));
+            WIN_ReleasePtr( wndPtr );
+        }
+    }
+
+    if (is_winproc)
+    {
+        WNDPROC new_proc = WINPROC_AllocProc( (WNDPROC)newval, WIN_PROC_16 );
+        WNDPROC old_proc = (WNDPROC)SetWindowLongA( WIN_Handle32(hwnd), offset, (LONG_PTR)new_proc );
+        return (LONG)WINPROC_GetProc( (WNDPROC)old_proc, WIN_PROC_16 );
+    }
+    else return SetWindowLongA( WIN_Handle32(hwnd), offset, newval );
 }