From ce79a887c4ccc1c61e2b226bcaaa7c913dccfabe Mon Sep 17 00:00:00 2001
From: Beman <bdawes@acm.org>
Date: Mon, 28 Aug 2017 07:32:08 -0400
Subject: [PATCH] Add BOOST_CONSTEXPR where required by C++ Std
 [bitmark.types]. Add operator! and function bitmask_set as Boost extensions.

---
 include/boost/detail/bitmask.hpp | 29 ++++++++++++++++++++---------
 1 file changed, 20 insertions(+), 9 deletions(-)

diff --git a/include/boost/detail/bitmask.hpp b/include/boost/detail/bitmask.hpp
index c6714a1..63d4fac 100644
--- a/include/boost/detail/bitmask.hpp
+++ b/include/boost/detail/bitmask.hpp
@@ -6,42 +6,53 @@
 //  http://www.boost.org/LICENSE_1_0.txt
 
 //  Usage:  enum foo { a=1, b=2, c=4 };
-//          BOOST_BITMASK( foo );
+//          BOOST_BITMASK( foo )
 //
 //          void f( foo arg );
 //          ...
 //          f( a | c );
+//
+//  See [bitmask.types] in the C++ standard for the formal specification
 
 #ifndef BOOST_BITMASK_HPP
 #define BOOST_BITMASK_HPP
 
+#include <boost/config.hpp>
 #include <boost/cstdint.hpp>
 
 #define BOOST_BITMASK(Bitmask)                                            \
                                                                           \
-  inline Bitmask operator| (Bitmask x , Bitmask y )                       \
+  inline BOOST_CONSTEXPR Bitmask operator| (Bitmask x , Bitmask y )       \
   { return static_cast<Bitmask>( static_cast<boost::int_least32_t>(x)     \
       | static_cast<boost::int_least32_t>(y)); }                          \
                                                                           \
-  inline Bitmask operator& (Bitmask x , Bitmask y )                       \
+  inline BOOST_CONSTEXPR Bitmask operator& (Bitmask x , Bitmask y )       \
   { return static_cast<Bitmask>( static_cast<boost::int_least32_t>(x)     \
       & static_cast<boost::int_least32_t>(y)); }                          \
                                                                           \
-  inline Bitmask operator^ (Bitmask x , Bitmask y )                       \
+  inline BOOST_CONSTEXPR Bitmask operator^ (Bitmask x , Bitmask y )       \
   { return static_cast<Bitmask>( static_cast<boost::int_least32_t>(x)     \
       ^ static_cast<boost::int_least32_t>(y)); }                          \
                                                                           \
-  inline Bitmask operator~ (Bitmask x )                                   \
+  inline BOOST_CONSTEXPR Bitmask operator~ (Bitmask x )                   \
   { return static_cast<Bitmask>(~static_cast<boost::int_least32_t>(x)); } \
                                                                           \
-  inline Bitmask & operator&=(Bitmask & x , Bitmask y)                    \
+  inline Bitmask & operator&=(Bitmask& x , Bitmask y)                     \
   { x = x & y ; return x ; }                                              \
                                                                           \
-  inline Bitmask & operator|=(Bitmask & x , Bitmask y)                    \
+  inline Bitmask & operator|=(Bitmask& x , Bitmask y)                     \
   { x = x | y ; return x ; }                                              \
                                                                           \
-  inline Bitmask & operator^=(Bitmask & x , Bitmask y)                    \
-  { x = x ^ y ; return x ; }                                              
+  inline Bitmask & operator^=(Bitmask& x , Bitmask y)                     \
+  { x = x ^ y ; return x ; }                                              \
+                                                                          \
+  /* Boost extensions to [bitmask.types] */                               \
+                                                                          \
+  inline BOOST_CONSTEXPR bool operator!(Bitmask x)                        \
+  { return !static_cast<int>(x); }                                        \
+                                                                          \
+  inline BOOST_CONSTEXPR bool bitmask_set(Bitmask x)                      \
+  { return !!x; }
 
 #endif // BOOST_BITMASK_HPP