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