Feature/concurrent node containers (#271)

* added concurrent node containers

* removed spurious typename

* added missing includes

* avoided unused param warning

* worked around Clang bug

* s/{}/() to work around GCC4.8 problems with aggregate initialization

* used /bigobj for cfoa/visit_tests.cpp

* suppressed localized maybe-uninitialized warnings

* fixed comments

* added /bigobj to cfoa/insert_tests.cpp

* instrumented double exact comparison to spot a spurious error

* fixed pedantic error

* refactored byte_span machinery

* compromised on sub-epsilon equality for doubles that should be identical

* documented boost::concurrent_node_(map|set)

* added concurrent_node_set

* added missing AlternativeType

* tested empty node insertion

* tested node_handle allocator management

* added nonassignable_allocator and node_handle_allocator_swap_tests

* fixed warning disabling

* silenced spurious GCC warning

* broadened scope of previous pragma

* broadened even more

* worked around spurious constexpr-related msvc-14.0 bug
https://godbolt.org/z/v78545Ebf

* added workaround back

* replaced previous workaround with built-in one

* added workaround back on top of built-in solution (which doesn't work 100% of the time)

test/cfoa/visit_tests.cpp

@@ -17,6 +17,8 @@
 
 #include <boost/unordered/concurrent_flat_map.hpp>
 #include <boost/unordered/concurrent_flat_set.hpp>
+#include <boost/unordered/concurrent_node_map.hpp>
+#include <boost/unordered/concurrent_node_set.hpp>
 
 #include <boost/compat/latch.hpp>
 #include <boost/core/ignore_unused.hpp>
@@ -971,9 +973,15 @@ namespace {
   boost::unordered::concurrent_flat_map<raii, raii>* map;
   boost::unordered::concurrent_flat_map<raii, raii, transp_hash,
     transp_key_equal>* transp_map;
+  boost::unordered::concurrent_node_map<raii, raii>* node_map;
+  boost::unordered::concurrent_node_map<raii, raii, transp_hash,
+    transp_key_equal>* transp_node_map;
   boost::unordered::concurrent_flat_set<raii>* set;
   boost::unordered::concurrent_flat_set<raii, transp_hash,
     transp_key_equal>* transp_set;
+  boost::unordered::concurrent_node_set<raii>* node_set;
+  boost::unordered::concurrent_node_set<raii, transp_hash,
+    transp_key_equal>* transp_node_set;
 
   struct mutable_pair
   {
@@ -1114,7 +1122,9 @@ namespace {
   }
 
   boost::concurrent_flat_set<
-    mutable_pair,  mutable_pair_hash,  mutable_pair_equal_to>* mutable_set;
+    mutable_pair, mutable_pair_hash, mutable_pair_equal_to>* mutable_set;
+  boost::concurrent_node_set<
+    mutable_pair, mutable_pair_hash, mutable_pair_equal_to>* mutable_node_set;
 
 } // namespace
 
@@ -1126,7 +1136,7 @@ using test::sequential;
 
 UNORDERED_TEST(
   visit,
-  ((map)(set))
+  ((map)(node_map)(set)(node_set))
   ((value_type_generator_factory)(init_type_generator_factory))
   ((lvalue_visitor)(visit_all)(visit_while)(exec_policy_visit_all)
    (exec_policy_visit_while))
@@ -1134,28 +1144,29 @@ UNORDERED_TEST(
 
 UNORDERED_TEST(
   visit,
-  ((transp_map)(transp_set))
+  ((transp_map)(transp_node_map)(transp_set)(transp_node_set))
   ((value_type_generator_factory)(init_type_generator_factory))
   ((transp_visitor))
   ((default_generator)(sequential)(limited_range)))
 
 UNORDERED_TEST(
   empty_visit,
-  ((map)(transp_map)(set)(transp_set))
+  ((map)(transp_map)(node_map)(transp_node_map)
+   (set)(transp_set)(node_set)(transp_node_set))
   ((value_type_generator_factory)(init_type_generator_factory))
   ((default_generator)(sequential)(limited_range))
 )
 
 UNORDERED_TEST(
   insert_and_visit,
-  ((map)(set))
+  ((map)(node_map)(set)(node_set))
   ((value_type_generator_factory))
   ((sequential))
 )
 
 UNORDERED_TEST(
   bulk_visit,
-  ((map)(set))
+  ((map)(node_map)(set)(node_set))
   ((regular_key_extract))
   ((value_type_generator_factory))
   ((sequential))
@@ -1163,7 +1174,7 @@ UNORDERED_TEST(
 
 UNORDERED_TEST(
   bulk_visit,
-  ((transp_map)(transp_set))
+  ((transp_map)(transp_node_map)(transp_set)(transp_node_set))
   ((transp_key_extract))
   ((value_type_generator_factory))
   ((sequential))
@@ -1173,7 +1184,7 @@ UNORDERED_TEST(
 
 UNORDERED_TEST(
   exclusive_access_set_visit,
-  ((mutable_set))
+  ((mutable_set)(mutable_node_set))
 )
 
 // clang-format on