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- // Copyright (C) 2006-2009, 2012 Alexander Nasonov
- // Copyright (C) 2012 Lorenzo Caminiti
- // Distributed under the Boost Software License, Version 1.0
- // (see accompanying file LICENSE_1_0.txt or a copy at
- // http://www.boost.org/LICENSE_1_0.txt)
- // Home at http://www.boost.org/libs/scope_exit
- #include <boost/scope_exit.hpp>
- #include <boost/foreach.hpp>
- #include <boost/typeof/typeof.hpp>
- #include <boost/typeof/std/vector.hpp>
- #include BOOST_TYPEOF_INCREMENT_REGISTRATION_GROUP()
- #include <boost/detail/lightweight_test.hpp>
- #include <vector>
- #include <sstream>
- struct person {
- typedef unsigned int id_t;
- typedef unsigned int evolution_t;
-
- id_t id;
- evolution_t evolution;
- person(void) : id(0), evolution(0) {}
- friend std::ostream& operator<<(std::ostream& o, person const& p) {
- return o << "person(" << p.id << ", " << p.evolution << ")";
- }
- };
- BOOST_TYPEOF_REGISTER_TYPE(person)
- struct world {
- world(void) : next_id_(1) {}
- void add_person(person const& a_person);
- friend std::ostream& operator<<(std::ostream& o, world const& w) {
- o << "world(" << w.next_id_ << ", {";
- BOOST_FOREACH(person const& p, w.persons_) {
- o << " " << p << ", ";
- }
- return o << "})";
- }
- private:
- person::id_t next_id_;
- std::vector<person> persons_;
- };
- BOOST_TYPEOF_REGISTER_TYPE(world)
- void world::add_person(person const& a_person) {
- persons_.push_back(a_person);
- // This block must be no-throw.
- person& p = persons_.back();
- person::evolution_t checkpoint = p.evolution;
- BOOST_SCOPE_EXIT( (checkpoint) (&p) (&persons_) ) {
- if(checkpoint == p.evolution) persons_.pop_back();
- } BOOST_SCOPE_EXIT_END
- // ...
- checkpoint = ++p.evolution;
- // Assign new identifier to the person.
- person::id_t const prev_id = p.id;
- p.id = next_id_++;
- BOOST_SCOPE_EXIT( (checkpoint) (&p) (&next_id_) (prev_id) ) {
- if(checkpoint == p.evolution) {
- next_id_ = p.id;
- p.id = prev_id;
- }
- } BOOST_SCOPE_EXIT_END
- // ...
- checkpoint = ++p.evolution;
- }
- int main(void) {
- person adam, eva;
- std::ostringstream oss;
- oss << adam;
- BOOST_TEST(oss.str() == "person(0, 0)");
- oss.str("");
- oss << eva;
- BOOST_TEST(oss.str() == "person(0, 0)");
- world w;
- w.add_person(adam);
- w.add_person(eva);
- oss.str("");
- oss << w;
- BOOST_TEST(oss.str() == "world(3, { person(1, 2), person(2, 2), })");
- return boost::report_errors();
- }
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