diff --git a/src/arena.cpp b/src/arena.cpp
new file mode 100644
index 0000000..3358bbd
--- /dev/null
+++ b/src/arena.cpp
@@ -0,0 +1,27 @@
+#include "artic/arena.h"
+
+#include <cstdlib>
+
+Arena::Arena() : _block_size(4096) {
+    _data = { malloc(_block_size) };
+    _available = _block_size;
+}
+
+Arena::~Arena() {
+    for (auto& ptr : _data)
+        free(ptr);
+}
+
+void Arena::grow() {
+    _block_size *= 2;
+    _data.push_back( malloc(_block_size) );
+    _available = _block_size;
+}
+
+void* Arena::alloc(size_t size) {
+    while (size > _available)
+        grow();
+    size_t ptr = reinterpret_cast<size_t>(_data.back()) + _block_size - _available;
+    _available -= size;
+    return reinterpret_cast<void*>(ptr);
+}