1 files changed, 98 insertions, 0 deletions
diff --git a/stm32/src/menu.c b/stm32/src/menu.c
new file mode 100644
index 0000000..cb8ba97
--- /dev/null
+++ b/stm32/src/menu.c
@@ -0,0 +1,98 @@
+/*!
+ * Callback driven menu handler.
+ *
+ * The following is an implementation of a callback-driven menu system.
+ * It supports arbitrary levels of menus (limited by size of return stack)
+ * and supports arbitrary user events.
+ * 
+ * Author Stuart Longland <[email protected]>
+ * Copyright (C) 2015 FreeDV project.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License version 2.1,
+ * as published by the Free Software Foundation.  This program 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 General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this program; if not, see
+ * <http://www.gnu.org/licenses/>.
+ */
+
+#include "menu.h"
+#include <stdlib.h>
+
+/*!
+ * Return the Nth item on the stack.
+ */
+static const struct menu_stack_item_t* const menu_stack(
+		const struct menu_t* const menu,
+		uint8_t index)
+{
+	if (menu->stack_depth <= index)
+		return NULL;
+
+	return &(menu->stack[menu->stack_depth - index - 1]);
+}
+
+/*!
+ * Return the Nth item on the stack.
+ */
+const struct menu_item_t* const menu_item(
+		const struct menu_t* const menu, uint8_t index)
+{
+	const struct menu_stack_item_t* const current
+		= menu_stack(menu, index);
+
+	if (!current)
+		return NULL;
+	return current->item;
+}
+
+/*!
+ * Enter a (sub)-menu.
+ */
+int menu_enter(struct menu_t* const menu,
+		const struct menu_item_t* const item)
+{
+	if (menu->stack_depth == MENU_STACK_SZ)
+		return -1;
+
+	menu->stack[menu->stack_depth].item = item;
+	menu->stack[menu->stack_depth].index = menu->current;
+	menu->stack_depth++;
+
+	(item->event_cb)(menu, MENU_EVT_ENTERED);
+
+	return 0;
+}
+
+/*!
+ * Return from a (sub)-menu.
+ */
+void menu_leave(struct menu_t* const menu)
+{
+	if (!menu->stack_depth)
+		return;	/* Already out of the menu */
+
+	menu->last = menu_item(menu, 0);
+	menu->stack_depth--;
+
+	const struct menu_stack_item_t* current = menu_stack(menu, 0);
+	if (current && current->item) {
+		menu->current = current->index;
+		(current->item->event_cb)(menu, MENU_EVT_RETURNED);
+	}
+}
+
+/*!
+ * Execute the callback for the current item with a user-supplied event.
+ */
+void menu_exec(struct menu_t* const menu, uint32_t event)
+{
+	const struct menu_item_t* item = menu_item(menu, 0);
+	if (item && item->event_cb)
+		(item->event_cb)(menu, event);
+}