From 2ffc663dd5c778c5a2e847e91b32dc87c40143e3 Mon Sep 17 00:00:00 2001
From: Douglas Gregor <doug.gregor@gmail.com>
Date: Tue, 2 Sep 2003 22:41:10 +0000
Subject: [PATCH] Also check structs with a single element of varying types
 when searching for a type with a particular alignment.

[SVN r19908]
---
 .../boost/type_traits/type_with_alignment.hpp | 24 ++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/include/boost/type_traits/type_with_alignment.hpp b/include/boost/type_traits/type_with_alignment.hpp
index 104169a..0ad3cdc 100644
--- a/include/boost/type_traits/type_with_alignment.hpp
+++ b/include/boost/type_traits/type_with_alignment.hpp
@@ -12,6 +12,8 @@
 #include "boost/preprocessor/list/for_each_i.hpp"
 #include "boost/preprocessor/tuple/to_list.hpp"
 #include "boost/preprocessor/cat.hpp"
+#include <boost/preprocessor/list/transform.hpp>
+#include <boost/preprocessor/list/append.hpp>
 #include "boost/type_traits/alignment_of.hpp"
 #include "boost/type_traits/is_pod.hpp"
 #include "boost/static_assert.hpp"
@@ -38,11 +40,22 @@ typedef void (*function_ptr)();
 typedef int (alignment_dummy::*member_ptr);
 typedef int (alignment_dummy::*member_function_ptr)();
 
-#define BOOST_TT_ALIGNMENT_TYPES BOOST_PP_TUPLE_TO_LIST( \
+#define BOOST_TT_ALIGNMENT_BASE_TYPES BOOST_PP_TUPLE_TO_LIST( \
         11, ( \
         char, short, int, long, float, double, long double \
         , void*, function_ptr, member_ptr, member_function_ptr))
 
+#define BOOST_TT_HAS_ONE_T(D,Data,T) boost::detail::has_one_T<T>
+
+#define BOOST_TT_ALIGNMENT_STRUCT_TYPES                         \
+        BOOST_PP_LIST_TRANSFORM(BOOST_TT_HAS_ONE_T,             \
+                                X,                              \
+                                BOOST_TT_ALIGNMENT_BASE_TYPES)
+
+#define BOOST_TT_ALIGNMENT_TYPES                                \
+        BOOST_PP_LIST_APPEND(BOOST_TT_ALIGNMENT_BASE_TYPES,     \
+                             BOOST_TT_ALIGNMENT_STRUCT_TYPES)
+
 #define BOOST_TT_CHOOSE_MIN_ALIGNMENT(R,P,I,T)                               \
         typename mpl::if_c<                                                  \
            (alignment_of<T>::value == target && !BOOST_PP_CAT(found,I)),     \
@@ -52,6 +65,12 @@ typedef int (alignment_dummy::*member_function_ptr)();
 
 #define BOOST_TT_CHOOSE_T(R,P,I,T) T BOOST_PP_CAT(t,I);
 
+template <typename T>
+struct has_one_T
+{
+  T data;
+};
+
 template <std::size_t target>
 union lower_alignment
 {
@@ -73,6 +92,9 @@ union max_align
         )
 };
 
+#undef BOOST_TT_ALIGNMENT_BASE_TYPES
+#undef BOOST_TT_HAS_ONE_T
+#undef BOOST_TT_ALIGNMENT_STRUCT_TYPES
 #undef BOOST_TT_ALIGNMENT_TYPES
 #undef BOOST_TT_CHOOSE_MIN_ALIGNMENT
 #undef BOOST_TT_CHOOSE_T