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/emplace_tests.cpp

@@ -1,5 +1,5 @@
 // Copyright (C) 2023 Christian Mazakas
-// Copyright (C) 2023 Joaquin M Lopez Munoz
+// Copyright (C) 2023-2024 Joaquin M Lopez Munoz
 // Copyright (C) 2024 Braden Ganetsky
 // Distributed under the Boost Software License, Version 1.0. (See accompanying
 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
@@ -9,6 +9,8 @@
 
 #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/core/ignore_unused.hpp>
 
@@ -80,11 +82,8 @@ namespace {
     }
     template <class T, class X> void operator()(std::vector<T>& values, X& x)
     {
-      static constexpr auto value_type_cardinality =
-        value_cardinality<typename X::value_type>::value;
-
       call_impl(values, x);
-      BOOST_TEST_GE(raii::move_constructor, value_type_cardinality * x.size());
+      BOOST_TEST_GE(raii::move_constructor, x.size());
     }
   } lvalue_emplacer;
 
@@ -197,7 +196,12 @@ namespace {
       BOOST_TEST_EQ(raii::default_constructor, 0u);
 
       BOOST_TEST_EQ(raii::copy_constructor, value_type_cardinality * x.size());
-      BOOST_TEST_GT(raii::move_constructor, 0u);
+      if (is_container_node_based<X>::value) {
+        BOOST_TEST_EQ(raii::move_constructor, 0u);
+      }
+      else {
+        BOOST_TEST_GT(raii::move_constructor, 0u);
+      }
 
       BOOST_TEST_EQ(raii::copy_assignment, 0u);
       BOOST_TEST_EQ(raii::move_assignment, 0u);
@@ -208,8 +212,8 @@ namespace {
   {
     template <class T, class X> void operator()(std::vector<T>& values, X& x)
     {
-      static constexpr auto value_type_cardinality =
-        value_cardinality<typename X::value_type>::value;
+      static constexpr auto input_type_nonconst_cardinality = 
+        value_nonconst_cardinality<T>::value;
 
       std::atomic<std::uint64_t> num_inserts{0};
       thread_runner(values, [&x, &num_inserts](boost::span<T> s) {
@@ -235,10 +239,18 @@ namespace {
       } else {
         BOOST_TEST_EQ(raii::copy_constructor, 0u);
       }
+
+      if (is_container_node_based<X>::value) {
+        BOOST_TEST_EQ(
+          raii::move_constructor, input_type_nonconst_cardinality * x.size());
+      }
+      else {
+        BOOST_TEST_GT(
+          raii::move_constructor, input_type_nonconst_cardinality * x.size());
+      }
 #if defined(BOOST_MSVC)
 #pragma warning(pop) // C4127
 #endif
-      BOOST_TEST_GT(raii::move_constructor, value_type_cardinality * x.size());
 
       BOOST_TEST_EQ(raii::copy_assignment, 0u);
       BOOST_TEST_EQ(raii::move_assignment, 0u);
@@ -280,7 +292,9 @@ namespace {
   }
 
   boost::unordered::concurrent_flat_map<raii, raii>* map;
+  boost::unordered::concurrent_node_map<raii, raii>* node_map;
   boost::unordered::concurrent_flat_set<raii>* set;
+  boost::unordered::concurrent_node_set<raii>* node_set;
 
 } // namespace
 
@@ -292,7 +306,7 @@ using test::sequential;
 
 UNORDERED_TEST(
   emplace,
-  ((map)(set))
+  ((map)(node_map)(set)(node_set))
   ((value_type_generator_factory)(init_type_generator_factory))
   ((lvalue_emplacer)(norehash_lvalue_emplacer)
    (lvalue_emplace_or_cvisit)(lvalue_emplace_or_visit)(copy_emplacer)(move_emplacer))
@@ -455,6 +469,8 @@ namespace {
 
   boost::unordered::concurrent_flat_map<counted_key_type, counted_value_type>*
     test_counted_flat_map = {};
+  boost::unordered::concurrent_node_map<counted_key_type, counted_value_type>*
+    test_counted_node_map = {};
 
 } // namespace
 
@@ -462,7 +478,7 @@ namespace {
 
 UNORDERED_TEST(
   emplace_map_key_value,
-  ((test_counted_flat_map))
+  ((test_counted_flat_map)(test_counted_node_map))
   ((copy)(move))
   ((counted_key_checker)(converting_key_checker))
   ((counted_value_checker)(converting_value_checker))