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- // Copyright 2010, Niels Dekker.
- //
- // Distributed under the Boost Software License, Version 1.0. (See
- // accompanying file LICENSE_1_0.txt or copy at
- // http://www.boost.org/LICENSE_1_0.txt)
- //
- // Test program for boost::initialized<T>.
- //
- // 2 May 2010 (Created) Niels Dekker
- #include <boost/utility/value_init.hpp>
- #include <boost/core/lightweight_test.hpp>
- #include <string>
- namespace
- {
- // Typical use case for boost::initialized<T>: A generic class that
- // holds a value of type T, which must be initialized by either
- // value-initialization or direct-initialization.
- template <class T> class key_value_pair
- {
- std::string m_key;
- boost::initialized<T> m_value;
- public:
-
- // Value-initializes the object held by m_value.
- key_value_pair() { }
- // Value-initializes the object held by m_value.
- explicit key_value_pair(const std::string& key)
- :
- m_key(key)
- {
- }
- // Direct-initializes the object held by m_value.
- key_value_pair(const std::string& key, const T& value)
- :
- m_key(key), m_value(value)
- {
- }
- const T& get_value() const
- {
- return m_value;
- }
- };
- // Tells whether the argument is value-initialized.
- bool is_value_initialized(const int& arg)
- {
- return arg == 0;
- }
- // Tells whether the argument is value-initialized.
- bool is_value_initialized(const std::string& arg)
- {
- return arg.empty();
- }
- struct foo
- {
- int data;
- };
- bool operator==(const foo& lhs, const foo& rhs)
- {
- return lhs.data == rhs.data;
- }
- // Tells whether the argument is value-initialized.
- bool is_value_initialized(const foo& arg)
- {
- return arg.data == 0;
- }
- template <class T>
- void test_key_value_pair(const T& magic_value)
- {
- // The value component of a default key_value_pair must be value-initialized.
- key_value_pair<T> default_key_value_pair;
- BOOST_TEST( is_value_initialized(default_key_value_pair.get_value() ) );
- // The value component of a key_value_pair that only has its key explicitly specified
- // must also be value-initialized.
- BOOST_TEST( is_value_initialized(key_value_pair<T>("key").get_value()) );
- // However, the value component of the following key_value_pair must be
- // "magic_value", as it must be direct-initialized.
- BOOST_TEST( key_value_pair<T>("key", magic_value).get_value() == magic_value );
- }
- }
- // Tests boost::initialize for a fundamental type, a type with a
- // user-defined constructor, and a user-defined type without
- // a user-defined constructor.
- int main()
- {
- const int magic_number = 42;
- test_key_value_pair(magic_number);
- const std::string magic_string = "magic value";
- test_key_value_pair(magic_string);
- const foo magic_foo = { 42 };
- test_key_value_pair(magic_foo);
- return boost::report_errors();
- }
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