| 1 | // optional_last_value function object (documented as part of Boost.Signals2) |
|---|---|
| 2 | |
| 3 | // Copyright Frank Mori Hess 2007-2008. |
| 4 | // Copyright Douglas Gregor 2001-2003. |
| 5 | // Distributed under the Boost Software License, Version |
| 6 | // 1.0. (See accompanying file LICENSE_1_0.txt or copy at |
| 7 | // http://www.boost.org/LICENSE_1_0.txt) |
| 8 | |
| 9 | // See http://www.boost.org/libs/signals2 for library home page. |
| 10 | |
| 11 | #ifndef BOOST_SIGNALS2_OPTIONAL_LAST_VALUE_HPP |
| 12 | #define BOOST_SIGNALS2_OPTIONAL_LAST_VALUE_HPP |
| 13 | |
| 14 | #include <boost/core/no_exceptions_support.hpp> |
| 15 | #include <boost/optional.hpp> |
| 16 | #include <boost/signals2/expired_slot.hpp> |
| 17 | |
| 18 | namespace boost { |
| 19 | namespace signals2 { |
| 20 | |
| 21 | template<typename T> |
| 22 | class optional_last_value |
| 23 | { |
| 24 | public: |
| 25 | typedef optional<T> result_type; |
| 26 | |
| 27 | template<typename InputIterator> |
| 28 | optional<T> operator()(InputIterator first, InputIterator last) const |
| 29 | { |
| 30 | optional<T> value; |
| 31 | while (first != last) |
| 32 | { |
| 33 | BOOST_TRY |
| 34 | { |
| 35 | value = *first; |
| 36 | } |
| 37 | BOOST_CATCH(const expired_slot &) {} |
| 38 | BOOST_CATCH_END |
| 39 | ++first; |
| 40 | } |
| 41 | return value; |
| 42 | } |
| 43 | }; |
| 44 | |
| 45 | template<> |
| 46 | class optional_last_value<void> |
| 47 | { |
| 48 | public: |
| 49 | typedef void result_type; |
| 50 | template<typename InputIterator> |
| 51 | result_type operator()(InputIterator first, InputIterator last) const |
| 52 | { |
| 53 | while (first != last) |
| 54 | { |
| 55 | BOOST_TRY |
| 56 | { |
| 57 | *first; |
| 58 | } |
| 59 | BOOST_CATCH(const expired_slot &) {} |
| 60 | BOOST_CATCH_END |
| 61 | ++first; |
| 62 | } |
| 63 | return; |
| 64 | } |
| 65 | }; |
| 66 | } // namespace signals2 |
| 67 | } // namespace boost |
| 68 | #endif // BOOST_SIGNALS2_OPTIONAL_LAST_VALUE_HPP |
| 69 |