boost_1_45_0/libs/conversion/test/lexical_cast_loopback_test.cpp

//  Unit test for boost::lexical_cast.
//
//  See http://www.boost.org for most recent version, including documentation.
//
//  Copyright Alexander Nasonov, 2006.
//
//  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 round-tripping conversion FPT -> string -> FPT,
//  where FPT is Floating Point Type.

#include <boost/config.hpp>

#if defined(__INTEL_COMPILER)
#pragma warning(disable: 193 383 488 981 1418 1419)
#elif defined(BOOST_MSVC)
#pragma warning(disable: 4097 4100 4121 4127 4146 4244 4245 4511 4512 4701 4800)
#endif

#include <boost/lexical_cast.hpp>
#include <boost/test/unit_test.hpp>

using namespace boost;

void test_round_conversion_float();
void test_round_conversion_double();
void test_round_conversion_long_double();

unit_test::test_suite *init_unit_test_suite(int, char *[])
{
    unit_test_framework::test_suite *suite =
        BOOST_TEST_SUITE("lexical_cast unit test");
    suite->add(BOOST_TEST_CASE(&test_round_conversion_float));
    suite->add(BOOST_TEST_CASE(&test_round_conversion_double));
    suite->add(BOOST_TEST_CASE(&test_round_conversion_long_double));

    return suite;
}

template<class T>
void test_round_conversion()
{
    T epsilon = std::numeric_limits<T>::epsilon();
    std::string const epsilon_s = boost::lexical_cast<std::string>(epsilon);
    BOOST_CHECK(epsilon == lexical_cast<T>(epsilon_s));

    T max_ = (std::numeric_limits<T>::max)();
    std::string const max_s = boost::lexical_cast<std::string>(max_);
    BOOST_CHECK(max_ == lexical_cast<T>(max_s));

    T min_ = (std::numeric_limits<T>::min)();
    std::string const min_s = boost::lexical_cast<std::string>(min_);
    BOOST_CHECK(min_ == lexical_cast<T>(min_s));

    T max_div137 = max_ / 137;
    std::string max_div137_s = boost::lexical_cast<std::string>(max_div137);
    BOOST_CHECK(max_div137 == lexical_cast<T>(max_div137_s));

    T epsilon_mult137 = epsilon * 137;
    std::string epsilon_mult137_s(lexical_cast<std::string>(epsilon_mult137));
    BOOST_CHECK(epsilon_mult137 == lexical_cast<T>(epsilon_mult137_s));

}

#if defined(BOOST_MSVC)
// See bug http://tinyurl.com/vhpvo
template<class T>
void test_msvc_magic_values()
{
    T magic_msvc = 0.00010000433948393407;
    std::string magic_msvc_s = boost::lexical_cast<std::string>(magic_msvc);
    BOOST_CHECK(magic_msvc == lexical_cast<T>(magic_msvc_s));
}
#endif

void test_round_conversion_float()
{
    test_round_conversion<float>();
}

void test_round_conversion_double()
{
    test_round_conversion<double>();
#if defined(BOOST_MSVC)
    test_msvc_magic_values<double>();
#endif
}

void test_round_conversion_long_double()
{
    test_round_conversion<long double>();
#if defined(BOOST_MSVC)
    test_msvc_magic_values<long double>();
#endif
}