1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/os/ossrv/ossrv_pub/boost_apis/boost/state_saver.hpp	Fri Jun 15 03:10:57 2012 +0200
     1.3 @@ -0,0 +1,94 @@
     1.4 +#ifndef BOOST_STATE_SAVER_HPP
     1.5 +#define BOOST_STATE_SAVER_HPP
     1.6 +
     1.7 +// MS compatible compilers support #pragma once
     1.8 +#if defined(_MSC_VER) && (_MSC_VER >= 1020)
     1.9 +# pragma once
    1.10 +#endif
    1.11 +
    1.12 +/////////1/////////2/////////3/////////4/////////5/////////6/////////7/////////8
    1.13 +// state_saver.hpp:
    1.14 +
    1.15 +// (C) Copyright 2003-4 Pavel Vozenilek and Robert Ramey - http://www.rrsd.com.
    1.16 +// Use, modification and distribution is subject to the Boost Software
    1.17 +// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
    1.18 +// http://www.boost.org/LICENSE_1_0.txt)
    1.19 +
    1.20 +//  See http://www.boost.org for updates, documentation, and revision history.
    1.21 +
    1.22 +// Inspired by Daryle Walker's iostate_saver concept.  This saves the original
    1.23 +// value of a variable when a state_saver is constructed and restores
    1.24 +// upon destruction.  Useful for being sure that state is restored to
    1.25 +// variables upon exit from scope.
    1.26 +
    1.27 +
    1.28 +#include <boost/config.hpp>
    1.29 +#ifndef BOOST_NO_EXCEPTIONS
    1.30 +    #include <exception>
    1.31 +#endif
    1.32 +
    1.33 +#include <boost/call_traits.hpp>
    1.34 +#include <boost/noncopyable.hpp>
    1.35 +#include <boost/type_traits/has_nothrow_copy.hpp>
    1.36 +#include <boost/detail/no_exceptions_support.hpp>
    1.37 +
    1.38 +#include <boost/mpl/eval_if.hpp>
    1.39 +#include <boost/mpl/identity.hpp>
    1.40 +
    1.41 +namespace boost {
    1.42 +
    1.43 +template<class T>
    1.44 +// T requirements:
    1.45 +//  - POD or object semantic (cannot be reference, function, ...)
    1.46 +//  - copy constructor
    1.47 +//  - operator = (no-throw one preferred)
    1.48 +class state_saver : private boost::noncopyable
    1.49 +{
    1.50 +private:
    1.51 +    const T previous_value;
    1.52 +    T & previous_ref;
    1.53 +
    1.54 +    struct restore {
    1.55 +        static void invoke(T & previous_ref, const T & previous_value){
    1.56 +            previous_ref = previous_value; // won't throw
    1.57 +        }
    1.58 +    };
    1.59 +
    1.60 +    struct restore_with_exception {
    1.61 +        static void invoke(T & previous_ref, const T & previous_value){
    1.62 +            BOOST_TRY{
    1.63 +                previous_ref = previous_value;
    1.64 +            } 
    1.65 +            BOOST_CATCH(::std::exception &) { 
    1.66 +                // we must ignore it - we are in destructor
    1.67 +            }
    1.68 +            BOOST_CATCH_END
    1.69 +        }
    1.70 +    };
    1.71 +
    1.72 +public:
    1.73 +    state_saver(
    1.74 +        T & object
    1.75 +    ) : 
    1.76 +        previous_value(object),
    1.77 +        previous_ref(object) 
    1.78 +    {}
    1.79 +    
    1.80 +    ~state_saver() {
    1.81 +        #ifndef BOOST_NO_EXCEPTIONS
    1.82 +            typedef BOOST_DEDUCED_TYPENAME mpl::eval_if<
    1.83 +                has_nothrow_copy<T>,
    1.84 +                mpl::identity<restore>,
    1.85 +                mpl::identity<restore_with_exception>
    1.86 +            >::type typex;
    1.87 +            typex::invoke(previous_ref, previous_value);
    1.88 +        #else
    1.89 +            previous_ref = previous_value;
    1.90 +        #endif
    1.91 +    }
    1.92 +
    1.93 +}; // state_saver<>
    1.94 +
    1.95 +} // boost
    1.96 +
    1.97 +#endif //BOOST_STATE_SAVER_HPP