implemented arena allocator

core/arena.h

@@ -0,0 +1,43 @@
+// SPDX-License-Identifier: BSD-3-Clause
+#ifndef ARENA_H
+#define ARENA_H
+
+#include "../types.h"
+
+/*
+ * An arena is a fast allocator that just
+ * keeps everything in a contiguous chunk
+ * of memory and moves a "pointer" when
+ * allocating new memory. The allocated
+ * memory is then free'd all at once.
+ */
+struct arena_allocator {
+	usize size;
+	usize base;
+	usize position;
+};
+
+
+/* Create a new arena allocator of size `size` */
+struct arena_allocator *arena_init(usize size);
+/* Destroy the allocator and */
+void arena_deinit(struct arena_allocator *allocator);
+
+/*
+ * Allocate a chunk of memory of size `size` on the
+ * arena.
+ */
+void *arena_alloc(struct arena_allocator *allocator, usize size);
+/*
+ * Same as `arena_alloc()` but also set all the allocated
+ * memory to zero.
+ */
+void *arena_zalloc(struct arena_allocator *allocator, usize size);
+/*
+ * Free all the allocated memory at once.
+ * This just sets the allocator cursor to its
+ * starting position.
+ */
+void arena_bump(struct arena_allocator *allocator);
+
+#endif