range/detail/safe_bool.hpp

0001 //  This header intentionally has no include guards.
0002 //
0003 //  Copyright (c) 2010 Neil Groves
0004 //  Distributed under the Boost Software License, Version 1.0.
0005 //  See accompanying file LICENSE_1_0.txt or copy at
0006 //  http://www.boost.org/LICENSE_1_0.txt
0007 //
0008 // This code utilises the experience gained during the evolution of
0009 // <boost/smart_ptr/operator_bool.hpp>
0010 #ifndef BOOST_RANGE_SAFE_BOOL_INCLUDED_HPP
0011 #define BOOST_RANGE_SAFE_BOOL_INCLUDED_HPP
0012
0013 #include <boost/config.hpp>
0014 #include <boost/range/config.hpp>
0015
0016 namespace boost
0017 {
0018     namespace range_detail
0019     {
0020
0021 template<class DataMemberPtr>
0022 class safe_bool
0023 {
0024 public:
0025     typedef safe_bool this_type;
0026
0027 #if (defined(__SUNPRO_CC) && BOOST_WORKAROUND(__SUNPRO_CC, < 0x570)) || defined(__CINT_)
0028     typedef bool unspecified_bool_type;
0029     static unspecified_bool_type to_unspecified_bool(const bool x, DataMemberPtr)
0030     {
0031         return x;
0032     }
0033 #elif defined(_MANAGED)
0034     static void unspecified_bool(this_type***)
0035     {
0036     }
0037     typedef void(*unspecified_bool_type)(this_type***);
0038     static unspecified_bool_type to_unspecified_bool(const bool x, DataMemberPtr)
0039     {
0040         return x ? unspecified_bool : 0;
0041     }
0042 #elif \
0043     ( defined(__MWERKS__) && BOOST_WORKAROUND(__MWERKS__, < 0x3200) ) || \
0044     ( defined(__GNUC__) && (__GNUC__ * 100 + __GNUC_MINOR__ < 304) ) || \
0045     ( defined(__SUNPRO_CC) && BOOST_WORKAROUND(__SUNPRO_CC, <= 0x590) )
0046
0047     typedef bool (this_type::*unspecified_bool_type)() const;
0048
0049     static unspecified_bool_type to_unspecified_bool(const bool x, DataMemberPtr)
0050     {
0051         return x ? &this_type::detail_safe_bool_member_fn : 0;
0052     }
0053 private:
0054     bool detail_safe_bool_member_fn() const { return false; }
0055 #else
0056     typedef DataMemberPtr unspecified_bool_type;
0057     static unspecified_bool_type to_unspecified_bool(const bool x, DataMemberPtr p)
0058     {
0059         return x ? p : 0;
0060     }
0061 #endif
0062 private:
0063     safe_bool();
0064     safe_bool(const safe_bool&);
0065     void operator=(const safe_bool&);
0066     ~safe_bool();
0067 };
0068
0069     } // namespace range_detail
0070 } // namespace boost
0071
0072 #endif // include guard