Implement allocator access utilities

test/allocator_construct_test.cpp

@@ -0,0 +1,49 @@
+/*
+Copyright 2020 Glen Joseph Fernandes
+(glenjofe@gmail.com)
+
+Distributed under the Boost Software License, Version 1.0.
+(http://www.boost.org/LICENSE_1_0.txt)
+*/
+#include <boost/core/allocator_access.hpp>
+#include <boost/core/default_allocator.hpp>
+#include <boost/core/lightweight_test.hpp>
+
+struct S {
+    S(int v)
+        : value(v) { }
+
+    int value;
+};
+
+struct A1 { };
+
+#if defined(BOOST_CORE_ALLOCATOR_DETECTION)
+struct A2 {
+    void construct(S* p, int v) {
+        new(p) S(v + 1);
+    }
+};
+#endif
+
+int main()
+{
+    boost::default_allocator<S> d;
+    {
+        S* p = d.allocate(1);
+        A1 a;
+        boost::allocator_construct(a, p, 1);
+        BOOST_TEST_EQ(p->value, 1);
+        d.deallocate(p, 1);
+    }
+#if defined(BOOST_CORE_ALLOCATOR_DETECTION)
+    {
+        S* p = d.allocate(1);
+        A2 a;
+        boost::allocator_construct(a, p, 1);
+        BOOST_TEST_EQ(p->value, 2);
+        d.deallocate(p, 1);
+    }
+#endif
+    return boost::report_errors();
+}