From 5c3576c7c6756b5791de0cb2dd4d7a9673a056ef Mon Sep 17 00:00:00 2001
From: Peter Dimov <pdimov@gmail.com>
Date: Tue, 18 Jan 2022 20:17:31 +0200
Subject: [PATCH] Add test/unordered/mix_policy.cpp

---
 test/Jamfile.v2               |  1 +
 test/unordered/mix_policy.cpp | 46 +++++++++++++++++++++++++++++++++++
 2 files changed, 47 insertions(+)
 create mode 100644 test/unordered/mix_policy.cpp

diff --git a/test/Jamfile.v2 b/test/Jamfile.v2
index d2573d20..560d92ad 100644
--- a/test/Jamfile.v2
+++ b/test/Jamfile.v2
@@ -65,6 +65,7 @@ test-suite unordered
         [ run unordered/transparent_tests.cpp ]
         [ run unordered/reserve_tests.cpp ]
         [ run unordered/contains_tests.cpp ]
+        [ run unordered/mix_policy.cpp ]
 
         [ run unordered/compile_set.cpp : :
             : <define>BOOST_UNORDERED_USE_MOVE
diff --git a/test/unordered/mix_policy.cpp b/test/unordered/mix_policy.cpp
new file mode 100644
index 00000000..87cd7b8c
--- /dev/null
+++ b/test/unordered/mix_policy.cpp
@@ -0,0 +1,46 @@
+// Copyright 2022 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/unordered/detail/implementation.hpp>
+#include <boost/core/bit.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <boost/cstdint.hpp>
+
+template<class Policy, class SizeT> void test( SizeT x )
+{
+    if( x <= 4 )
+    {
+        BOOST_TEST_EQ( Policy::new_bucket_count( x ), 4 );
+    }
+    else
+    {
+        BOOST_TEST_EQ( Policy::new_bucket_count( x ), boost::core::bit_ceil( x ) );
+    }
+
+    BOOST_TEST_EQ( Policy::prev_bucket_count( x ), boost::core::bit_floor( x ) );
+}
+
+int main()
+{
+    {
+        typedef boost::uint64_t SizeT;
+        typedef boost::unordered::detail::mix64_policy<SizeT> policy;
+
+        for( SizeT i = 1; i < 200; ++i )
+        {
+            test<policy>( i );
+        }
+
+        for( int i = 8; i < 64; ++i )
+        {
+            SizeT x = SizeT( 1 ) << i;
+
+            test<policy>( x - 1 );
+            test<policy>( x );
+            test<policy>( x + 1 );
+        }
+    }
+
+    return boost::report_errors();
+}