70 lines
1.7 KiB
C++
70 lines
1.7 KiB
C++
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// Copyright (C) 2008-2018 Lorenzo Caminiti
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// Distributed under the Boost Software License, Version 1.0 (see accompanying
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// file LICENSE_1_0.txt or a copy at http://www.boost.org/LICENSE_1_0.txt).
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// See: http://www.boost.org/doc/libs/release/libs/contract/doc/html/index.html
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#include <boost/contract.hpp>
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#include <cassert>
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//[static_public
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template<class C>
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class make {
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public:
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static void static_invariant() { // Static class invariants.
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BOOST_CONTRACT_ASSERT(instances() >= 0);
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}
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// Contract for a static public function.
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static int instances() {
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// Explicit template parameter `make` (check static invariants).
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boost::contract::check c = boost::contract::public_function<make>();
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return instances_; // Function body.
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}
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/* ... */
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//]
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make() : object() {
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boost::contract::old_ptr<int> old_instances =
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BOOST_CONTRACT_OLDOF(instances());
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boost::contract::check c = boost::contract::constructor(this)
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.postcondition([&] {
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BOOST_CONTRACT_ASSERT(instances() == *old_instances + 1);
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})
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;
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++instances_;
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}
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~make() {
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boost::contract::old_ptr<int> old_instances =
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BOOST_CONTRACT_OLDOF(instances());
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boost::contract::check c = boost::contract::destructor(this)
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.postcondition([&] { // (An example of destructor postconditions.)
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BOOST_CONTRACT_ASSERT(instances() == *old_instances - 1);
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})
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;
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--instances_;
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}
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C object;
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private:
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static int instances_;
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};
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template<class C>
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int make<C>::instances_ = 0;
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int main() {
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struct x {};
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make<x> x1, x2, x3;
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assert(make<x>::instances() == 3);
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return 0;
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}
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