enum: Add functions to add and remove mappings from enum names

Co-authored-by: Thomas Egerer <[email protected]>

src/libstrongswan/utils/enum.c

@@ -1,4 +1,5 @@
 /*
+ * Copyright (C) 2023 Tobias Brunner
  * Copyright (C) 2006 Martin Willi
  *
  * Copyright (C) secunet Security Networks AG
@@ -23,6 +24,49 @@
 
 #include "enum.h"
 
+/*
+ * Described in header
+ */
+void enum_add_enum_names(enum_name_t *e, enum_name_t *names)
+{
+	if (e)
+	{
+		do
+		{
+			if (!e->next)
+			{
+				e->next = names;
+				break;
+			}
+			else if (e->next == names)
+			{
+				break;
+			}
+		}
+		while ((e = e->next));
+	}
+}
+
+/*
+ * Described in header
+ */
+void enum_remove_enum_names(enum_name_t *e, enum_name_t *names)
+{
+	if (e)
+	{
+		do
+		{
+			if (e->next == names)
+			{
+				e->next = names->next;
+				names->next = NULL;
+				break;
+			}
+		}
+		while ((e = e->next));
+	}
+}
+
 /**
  * See header.
  */

src/libstrongswan/utils/enum.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2009-2019 Tobias Brunner
+ * Copyright (C) 2009-2023 Tobias Brunner
  * Copyright (C) 2006-2008 Martin Willi
  *
  * Copyright (C) secunet Security Networks AG
@@ -140,6 +140,41 @@ struct enum_name_t {
 			countof(((char*[]){__VA_ARGS__}))), \
 		ENUM_FLAG_MAGIC, { unset, __VA_ARGS__ }}; ENUM_END(name, last)
 
+/**
+ * Define a static enum name that can be added and removed to an existing list
+ * via enum_add_enum_names() and enum_remove_enum_names(), respectively.
+ *
+ * @param name		name of the static enum_name element
+ * @param first		enum value of the first enum string
+ * @param last		enum value of the last enum string
+ * @param ...		a list of strings
+ */
+#define ENUM_EXT(name, first, last, ...) \
+	ENUM_BEGIN(name, first, last, __VA_ARGS__); static ENUM_END(name, last)
+
+/**
+ * Register enum names for additional enum values with an existing enum name.
+ *
+ * @note Must be called while running single-threaded, e.g. when plugins and
+ * their features are loaded. Use enum_remove_enum_names() to remove the names
+ * during deinitialization.
+ *
+ * @param e		enum names to add new names to
+ * @param names	additional enum names
+ */
+void enum_add_enum_names(enum_name_t *e, enum_name_t *names);
+
+/**
+ * Remove previously registered enum names.
+ *
+ * @note Must be called while running single-threaded, e.g. when plugins and
+ * their features are unloaded.
+ *
+ * @param e		enum names to remove previously added names from
+ * @param names	additional enum names to remove
+ */
+void enum_remove_enum_names(enum_name_t *e, enum_name_t *names);
+
 /**
  * Convert a enum value to its string representation.
  *