整理

include/boost/align/detail/align_down.hpp

@@ -0,0 +1,28 @@
+/*
+Copyright 2015 Glen Joseph Fernandes
+(glenjofe@gmail.com)
+
+Distributed under the Boost Software License, Version 1.0.
+(http://www.boost.org/LICENSE_1_0.txt)
+*/
+#ifndef BOOST_ALIGN_DETAIL_ALIGN_DOWN_HPP
+#define BOOST_ALIGN_DETAIL_ALIGN_DOWN_HPP
+
+#include <boost/align/detail/is_alignment.hpp>
+#include <boost/assert.hpp>
+
+namespace boost {
+namespace alignment {
+
+inline void*
+align_down(void* ptr, std::size_t alignment) BOOST_NOEXCEPT
+{
+    BOOST_ASSERT(detail::is_alignment(alignment));
+    return reinterpret_cast<void*>(~(alignment - 1) &
+        reinterpret_cast<std::size_t>(ptr));
+}
+
+} /* alignment */
+} /* boost */
+
+#endif