xo-alloc2: work on fomo Arena

src/alloc2/IAllocator_DArena.cpp

@@ -0,0 +1,56 @@
+/** @file IAllocator_DArena.cpp
+ *
+ *  @author Roland Conybeare, Dec 2025
+ **/
+
+#include "IAllocator_DArena.hpp"
+#include <cassert>
+
+namespace xo {
+    namespace mm {
+
+        std::size_t
+        IAllocator_Impl<DArena>::size(const DArena & s) {
+            return s.limit_ - s.lo_;
+        }
+
+        std::size_t
+        IAllocator_Impl<DArena>::committed(const DArena & s) {
+            return s.committed_z_;
+        }
+
+        bool
+        IAllocator_Impl<DArena>::contains(const DArena & s,
+                                          const void * p)
+        {
+            return (s.lo_ <= p) && (p < s.hi_);
+        }
+
+        std::byte *
+        IAllocator_Impl<DArena>::alloc(const DArena & s,
+                                       std::size_t z)
+        {
+            (void)s;
+            (void)z;
+
+            // scope log(XO_DEBUG(config_.debug_flag_));
+
+            assert(false);
+        }
+
+        void
+        IAllocator_Impl<DArena>::clear(DArena & s)
+        {
+            s.free_ = s.lo_;
+            //s.checkpoint_ = s.lo_;
+        }
+
+         void
+         IAllocator_Impl<DArena>::destruct_data(DArena & s)
+         {
+             s.~DArena();
+         }
+    } /*namespace mm*/
+} /*namespace xo*/
+
+/* end IAllocator_DArena.cpp */