1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283848586878889 |
- // Copyright (C) 2008-2018 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).
- // See: http://www.boost.org/doc/libs/release/libs/contract/doc/html/index.html
- #include <boost/contract.hpp>
- #include <vector>
- #include <cassert>
- //[pure_virtual_public_base_begin
- template<typename Iterator>
- class range {
- public:
- // Pure virtual function declaration (contract in definition below).
- virtual Iterator begin(boost::contract::virtual_* v = 0) = 0;
- //]
- // Could program class invariants and contracts for the following too.
- virtual Iterator end() = 0;
- virtual bool empty() const = 0;
- //[pure_virtual_public_base_end
- /* ... */
- };
- //]
- //[pure_virtual_public_base_impl
- // Pure virtual function default implementation (out-of-line in C++).
- template<typename Iterator>
- Iterator range<Iterator>::begin(boost::contract::virtual_* v) {
- Iterator result; // As usual, virtual pass `result` right after `v`...
- boost::contract::check c = boost::contract::public_function(v, result, this)
- .postcondition([&] (Iterator const& result) {
- if(empty()) BOOST_CONTRACT_ASSERT(result == end());
- })
- ;
- // Pure function body (never executed by this library).
- assert(false);
- return result;
- }
- //]
- template<typename T>
- class vector
- #define BASES public range<typename std::vector<T>::iterator>
- : BASES
- {
- public:
- typedef BOOST_CONTRACT_BASE_TYPES(BASES) base_types;
- #undef BASES
- typedef typename std::vector<T>::iterator iterator;
- iterator begin(boost::contract::virtual_* v = 0) /* override */ {
- iterator result;
- // Again, pass result right after `v`...
- boost::contract::check c = boost::contract::public_function<
- override_begin>(v, result, &vector::begin, this)
- // ...plus postconditions take `result` as parameter (not capture).
- .postcondition([&] (iterator const& result) {
- if(!empty()) BOOST_CONTRACT_ASSERT(*result == front());
- })
- ;
- return result = vect_.begin();
- }
- BOOST_CONTRACT_OVERRIDE(begin)
- // Could program class invariants and contracts for the following too.
- iterator end() { return vect_.end(); }
- bool empty() const { return vect_.empty(); }
- T const& front() const { return vect_.front(); }
- void push_back(T const& value) { vect_.push_back(value); }
- private:
- std::vector<T> vect_;
- };
- int main() {
- vector<int> v;
- v.push_back(1);
- v.push_back(2);
- v.push_back(3);
- range<std::vector<int>::iterator>& r = v;
- assert(*(r.begin()) == 1);
- return 0;
- }
|