base: introduce array utility

Fixes #4170

repos/base/include/util/array.h

@@ -0,0 +1,126 @@
+/*
+ * \brief   Array class
+ * \author  Stefan Kalkowski
+ * \date    2016-09-30
+ */
+
+/*
+ * Copyright (C) 2016-2021 Genode Labs GmbH
+ *
+ * This file is part of the Genode OS framework, which is distributed
+ * under the terms of the GNU Affero General Public License version 3.
+ */
+
+#ifndef _INCLUDE__UTIL__ARRAY_H_
+#define _INCLUDE__UTIL__ARRAY_H_
+
+namespace Genode { template <typename, unsigned> class Array; }
+
+
+/**
+ * Array with static size
+ *
+ * \param T    array element type
+ * \param MAX  maximum number of array elements
+ */
+template <typename T, unsigned MAX>
+class Genode::Array
+{
+	private:
+
+		unsigned _count { 0 };
+		T        _objs[MAX];
+
+	public:
+
+		struct Index_out_of_bounds {}; /* Exception type */
+
+		/**
+		 * Constructs an empty array
+		 */
+		Array() {}
+
+		/**
+		 * Constructs a filled array
+		 *
+		 * \param args  variable count of array elements
+		 */
+		template<typename ... ARGS>
+		Array(ARGS ... args)
+		{
+			static_assert(sizeof...(ARGS) <= MAX, "Array too small!");
+			add(args...);
+		}
+
+		/**
+		 * Return the count of elements inside the array
+		 */
+		unsigned count() const { return _count; }
+
+		/**
+		 * Return the array element specified by index
+		 *
+		 * \param idx  the index of the array element
+		 *
+		 * \throw Index_out_of_bounds
+		 */
+		T & value(unsigned idx)
+		{
+			if (idx >= _count)
+				throw Index_out_of_bounds();
+			return _objs[idx];
+		}
+
+		/**
+		 * Adds a single element to the array.
+		 *
+		 * The element gets inserted at position 'count()',
+		 * and 'count()' is incremented.
+		 *
+		 * \param obj  the element to be added
+		 *
+		 * \throw Index_out_of_bounds
+		 */
+		void add(T obj)
+		{
+			if ((_count + 1) > MAX)
+				throw Index_out_of_bounds();
+			_objs[_count++] = obj;
+		}
+
+		/**
+		 * Adds a variable count of elements to the array.
+		 *
+		 * The elements are getting inserted at position 'count()',
+		 * and 'count()' is increased by the number of elements given.
+		 *
+		 * \param obj   the first element to be added
+		 * \param tail  the tail of arguments
+		 *
+		 * \throw Index_out_of_bounds
+		 */
+		template<typename ... TAIL>
+		void add(T obj, TAIL ... tail)
+		{
+			add(obj);
+			add(tail...);
+		}
+
+		template <typename FUNC>
+		void for_each(FUNC const &f)
+		{
+			for (unsigned idx = 0; idx < _count; idx++)
+				f(idx, _objs[idx]);
+		}
+
+		template <typename FUNC>
+		void for_each(FUNC const &f) const
+		{
+			for (unsigned idx = 0; idx < _count; idx++) {
+				T const & obj = _objs[idx];
+				f(idx, obj);
+			}
+		}
+};
+
+#endif /* _INCLUDE__UTIL__ARRAY_H_ */