extmod/moductypes: Implement __int__ for PTR.

Allows to get address a pointer contains, as an integer.

extmod/moductypes.c

@@ -614,6 +614,25 @@ STATIC mp_obj_t uctypes_struct_subscr(mp_obj_t self_in, mp_obj_t index_in, mp_ob
     }
 }
 
+STATIC mp_obj_t uctypes_struct_unary_op(mp_unary_op_t op, mp_obj_t self_in) {
+    mp_obj_uctypes_struct_t *self = MP_OBJ_TO_PTR(self_in);
+    switch (op) {
+        case MP_UNARY_OP_INT:
+            if (MP_OBJ_IS_TYPE(self->desc, &mp_type_tuple)) {
+                mp_obj_tuple_t *t = MP_OBJ_TO_PTR(self->desc);
+                mp_int_t offset = MP_OBJ_SMALL_INT_VALUE(t->items[0]);
+                uint agg_type = GET_TYPE(offset, AGG_TYPE_BITS);
+                if (agg_type == PTR) {
+                    byte *p = *(void**)self->addr;
+                    return mp_obj_new_int((mp_int_t)(uintptr_t)p);
+                }
+            }
+            /* fallthru */
+
+        default: return MP_OBJ_NULL; // op not supported
+    }
+}
+
 STATIC mp_int_t uctypes_get_buffer(mp_obj_t self_in, mp_buffer_info_t *bufinfo, mp_uint_t flags) {
     (void)flags;
     mp_obj_uctypes_struct_t *self = MP_OBJ_TO_PTR(self_in);
@@ -662,6 +681,7 @@ STATIC const mp_obj_type_t uctypes_struct_type = {
     .make_new = uctypes_struct_make_new,
     .attr = uctypes_struct_attr,
     .subscr = uctypes_struct_subscr,
+    .unary_op = uctypes_struct_unary_op,
     .buffer_p = { .get_buffer = uctypes_get_buffer },
 };