boost/test/tools/detail/print_helper.hpp
// (C) Copyright Gennadiy Rozental 2001. // 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) // See http://www.boost.org/libs/test for the library home page. // // File : $RCSfile$ // // Version : $Revision: 74248 $ // // Description : defines level of indiration facilitating workarounds for non printable types // *************************************************************************** #ifndef BOOST_TEST_TOOLS_IMPL_COMMON_HPP_012705GER #define BOOST_TEST_TOOLS_IMPL_COMMON_HPP_012705GER // Boost.Test #include <boost/test/detail/config.hpp> #include <boost/test/detail/global_typedef.hpp> // Boost #include <boost/mpl/or.hpp> #include <boost/static_assert.hpp> #include <boost/type_traits/is_array.hpp> #include <boost/type_traits/is_function.hpp> #include <boost/type_traits/is_abstract.hpp> #include <boost/type_traits/has_left_shift.hpp> #include <ios> #include <iostream> #include <limits> #if !defined(BOOST_NO_CXX11_NULLPTR) #include <cstddef> #endif #include <boost/test/detail/suppress_warnings.hpp> //____________________________________________________________________________// namespace boost { namespace test_tools { namespace tt_detail { // ************************************************************************** // // ************** boost_test_print_type ************** // // ************************************************************************** // namespace impl { template <class T> std::ostream& boost_test_print_type(std::ostream& ostr, T const& t) { BOOST_STATIC_ASSERT_MSG( (boost::has_left_shift<std::ostream,T>::value), "Type has to implement operator<< to be printable"); ostr << t; return ostr; } struct boost_test_print_type_impl { template <class R> std::ostream& operator()(std::ostream& ostr, R const& r) const { return boost_test_print_type(ostr, r); } }; } // To avoid ODR violations, see N4381 template <class T> struct static_const { static const T value; }; template <class T> const T static_const<T>::value = T(); namespace { static const impl::boost_test_print_type_impl& boost_test_print_type = static_const<impl::boost_test_print_type_impl>::value; } // ************************************************************************** // // ************** print_log_value ************** // // ************************************************************************** // template<typename T> struct print_log_value { void operator()( std::ostream& ostr, T const& t ) { typedef typename mpl::or_<is_array<T>,is_function<T>,is_abstract<T> >::type cant_use_nl; std::streamsize old_precision = set_precision( ostr, cant_use_nl() ); //ostr << t; using boost::test_tools::tt_detail::boost_test_print_type; boost_test_print_type(ostr, t); if( old_precision != (std::streamsize)-1 ) ostr.precision( old_precision ); } std::streamsize set_precision( std::ostream& ostr, mpl::false_ ) { if( std::numeric_limits<T>::is_specialized && std::numeric_limits<T>::radix == 2 ) return ostr.precision( 2 + std::numeric_limits<T>::digits * 301/1000 ); else if ( std::numeric_limits<T>::is_specialized && std::numeric_limits<T>::radix == 10 ) { #ifdef BOOST_NO_CXX11_NUMERIC_LIMITS // (was BOOST_NO_NUMERIC_LIMITS_LOWEST but now deprecated). // No support for std::numeric_limits<double>::max_digits10, // so guess that a couple of guard digits more than digits10 will display any difference. return ostr.precision( 2 + std::numeric_limits<T>::digits10 ); #else // std::numeric_limits<double>::max_digits10; IS supported. // Any noisy or guard digits needed to display any difference are included in max_digits10. return ostr.precision( std::numeric_limits<T>::max_digits10 ); #endif } // else if T is not specialized for std::numeric_limits<>, // then will just get the default precision of 6 digits. return (std::streamsize)-1; } std::streamsize set_precision( std::ostream&, mpl::true_ ) { return (std::streamsize)-1; } }; //____________________________________________________________________________// #if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x564)) template<typename T, std::size_t N > struct print_log_value< T[N] > { void operator()( std::ostream& ostr, T const* t ) { ostr << t; } }; #endif //____________________________________________________________________________// template<> struct BOOST_TEST_DECL print_log_value<bool> { void operator()( std::ostream& ostr, bool t ); }; //____________________________________________________________________________// template<> struct BOOST_TEST_DECL print_log_value<char> { void operator()( std::ostream& ostr, char t ); }; //____________________________________________________________________________// template<> struct BOOST_TEST_DECL print_log_value<unsigned char> { void operator()( std::ostream& ostr, unsigned char t ); }; //____________________________________________________________________________// template<> struct BOOST_TEST_DECL print_log_value<char const*> { void operator()( std::ostream& ostr, char const* t ); }; //____________________________________________________________________________// template<> struct BOOST_TEST_DECL print_log_value<wchar_t const*> { void operator()( std::ostream& ostr, wchar_t const* t ); }; #if !defined(BOOST_NO_CXX11_NULLPTR) template<> struct print_log_value<std::nullptr_t> { // declaration and definition is here because of #12969 https://svn.boost.org/trac10/ticket/12969 void operator()( std::ostream& ostr, std::nullptr_t /*t*/ ) { ostr << "nullptr"; } }; #endif //____________________________________________________________________________// // ************************************************************************** // // ************** print_helper ************** // // ************************************************************************** // // Adds level of indirection to the output operation, allowing us to customize // it for types that do not support operator << directly or for any other reason template<typename T> struct print_helper_t { explicit print_helper_t( T const& t ) : m_t( t ) {} T const& m_t; }; //____________________________________________________________________________// #if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x564)) // Borland suffers premature pointer decay passing arrays by reference template<typename T, std::size_t N > struct print_helper_t< T[N] > { explicit print_helper_t( T const * t ) : m_t( t ) {} T const * m_t; }; #endif //____________________________________________________________________________// template<typename T> inline print_helper_t<T> print_helper( T const& t ) { return print_helper_t<T>( t ); } //____________________________________________________________________________// template<typename T> inline std::ostream& operator<<( std::ostream& ostr, print_helper_t<T> const& ph ) { print_log_value<T>()( ostr, ph.m_t ); return ostr; } //____________________________________________________________________________// } // namespace tt_detail // ************************************************************************** // // ************** BOOST_TEST_DONT_PRINT_LOG_VALUE ************** // // ************************************************************************** // #define BOOST_TEST_DONT_PRINT_LOG_VALUE( the_type ) \ namespace boost{ namespace test_tools{ namespace tt_detail{ \ template<> \ struct print_log_value<the_type > { \ void operator()( std::ostream&, the_type const& ) {} \ }; \ }}} \ /**/ } // namespace test_tools } // namespace boost #include <boost/test/detail/enable_warnings.hpp> #endif // BOOST_TEST_TOOLS_IMPL_COMMON_HPP_012705GER