[CALC] Add support for HTML-Help. CORE-15019

base/applications/calc/htmlhelp.c

@@ -0,0 +1,67 @@
+/*
+ * ReactOS Calc (HtmlHelp support)
+ *
+ * Copyright 2007-2017, Carlo Bramini
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include "calc.h"
+
+#define GET_CB(name) \
+    calc_##name = (type_##name)GetProcAddress(hHtmlHelp, #name); \
+    if (calc_##name == NULL) calc_##name = dummy_##name;
+
+static HWND WINAPI
+dummy_HtmlHelpA(HWND hWnd, LPCSTR pszFile, UINT uCommand, DWORD dwData);
+
+static HWND WINAPI
+dummy_HtmlHelpW(HWND hWnd, LPCWSTR pszFile, UINT uCommand, DWORD dwData);
+
+type_HtmlHelpA calc_HtmlHelpA = dummy_HtmlHelpA;
+type_HtmlHelpW calc_HtmlHelpW = dummy_HtmlHelpW;
+
+static HMODULE hHtmlHelp;
+
+static HWND WINAPI
+dummy_HtmlHelpA(HWND hWnd, LPCSTR pszFile, UINT uCommand, DWORD dwData)
+{
+    return NULL;
+}
+
+static HWND WINAPI
+dummy_HtmlHelpW(HWND hWnd, LPCWSTR pszFile, UINT uCommand, DWORD dwData)
+{
+    return NULL;
+}
+
+void HtmlHelp_Start(HINSTANCE hInstance)
+{
+    hHtmlHelp = LoadLibrary(_T("HTMLHELP"));
+    if (hHtmlHelp == NULL)
+        return;
+
+    GET_CB(HtmlHelpW)
+    GET_CB(HtmlHelpA)
+}
+
+void HtmlHelp_Stop(void)
+{
+    if(hHtmlHelp == NULL)
+        return;
+
+    FreeLibrary(hHtmlHelp);
+    hHtmlHelp = NULL;
+}