tools/detail/print_helper.hpp

0001 //  (C) Copyright Gennadiy Rozental 2001.
0002 //  Distributed under the Boost Software License, Version 1.0.
0003 //  (See accompanying file LICENSE_1_0.txt or copy at
0004 //  http://www.boost.org/LICENSE_1_0.txt)
0005
0006 //  See http://www.boost.org/libs/test for the library home page.
0007 //
0008 //  File        : $RCSfile$
0009 //
0010 //  Version     : $Revision: 74248 $
0011 //
0012 //  Description : defines level of indiration facilitating workarounds for non printable types
0013 // ***************************************************************************
0014
0015 #ifndef BOOST_TEST_TOOLS_IMPL_COMMON_HPP_012705GER
0016 #define BOOST_TEST_TOOLS_IMPL_COMMON_HPP_012705GER
0017
0018 // Boost.Test
0019 #include <boost/test/detail/config.hpp>
0020 #include <boost/test/detail/global_typedef.hpp>
0021
0022 // Boost
0023 #include <boost/mpl/or.hpp>
0024 #include <boost/static_assert.hpp>
0025 #include <boost/type_traits/is_array.hpp>
0026 #include <boost/type_traits/is_function.hpp>
0027 #include <boost/type_traits/is_abstract.hpp>
0028 #include <boost/type_traits/has_left_shift.hpp>
0029
0030 #include <ios>
0031 #include <iostream>
0032 #include <limits>
0033
0034 #if !defined(BOOST_NO_CXX11_NULLPTR)
0035 #include <cstddef>
0036 #endif
0037
0038 #include <boost/test/detail/suppress_warnings.hpp>
0039
0040 //____________________________________________________________________________//
0041
0042 namespace boost {
0043 namespace test_tools {
0044 namespace tt_detail {
0045
0046 // ************************************************************************** //
0047 // **************          boost_test_print_type               ************** //
0048 // ************************************************************************** //
0049
0050     namespace impl {
0051         template <class T>
0052         std::ostream& boost_test_print_type(std::ostream& ostr, T const& t) {
0053             BOOST_STATIC_ASSERT_MSG( (boost::has_left_shift<std::ostream,T>::value),
0054                                     "Type has to implement operator<< to be printable");
0055             ostr << t;
0056             return ostr;
0057         }
0058
0059         struct boost_test_print_type_impl {
0060             template <class R>
0061             std::ostream& operator()(std::ostream& ostr, R const& r) const {
0062                 return boost_test_print_type(ostr, r);
0063             }
0064         };
0065     }
0066
0067     // To avoid ODR violations, see N4381
0068     template <class T> struct static_const { static const T value; };
0069     template <class T> const T static_const<T>::value = T();
0070
0071     namespace {
0072         static const impl::boost_test_print_type_impl& boost_test_print_type =
0073             static_const<impl::boost_test_print_type_impl>::value;
0074     }
0075
0076
0077 // ************************************************************************** //
0078 // **************                print_log_value               ************** //
0079 // ************************************************************************** //
0080
0081 template<typename T>
0082 struct print_log_value {
0083     void    operator()( std::ostream& ostr, T const& t )
0084     {
0085         typedef typename mpl::or_<is_array<T>,is_function<T>,is_abstract<T> >::type cant_use_nl;
0086
0087         std::streamsize old_precision = set_precision( ostr, cant_use_nl() );
0088
0089         //ostr << t;
0090         using boost::test_tools::tt_detail::boost_test_print_type;
0091         boost_test_print_type(ostr, t);
0092
0093         if( old_precision != (std::streamsize)-1 )
0094             ostr.precision( old_precision );
0095     }
0096
0097     std::streamsize set_precision( std::ostream& ostr, mpl::false_ )
0098     {
0099         if( std::numeric_limits<T>::is_specialized && std::numeric_limits<T>::radix == 2 )
0100             return ostr.precision( 2 + std::numeric_limits<T>::digits * 301/1000 );
0101         else if ( std::numeric_limits<T>::is_specialized && std::numeric_limits<T>::radix == 10 ) {
0102 #ifdef BOOST_NO_CXX11_NUMERIC_LIMITS
0103             // (was BOOST_NO_NUMERIC_LIMITS_LOWEST but now deprecated).
0104             // No support for std::numeric_limits<double>::max_digits10,
0105             // so guess that a couple of guard digits more than digits10 will display any difference.
0106             return ostr.precision( 2 + std::numeric_limits<T>::digits10 );
0107 #else
0108             // std::numeric_limits<double>::max_digits10; IS supported.
0109             // Any noisy or guard digits needed to display any difference are included in max_digits10.
0110             return ostr.precision( std::numeric_limits<T>::max_digits10 );
0111 #endif
0112         }
0113         // else if T is not specialized for std::numeric_limits<>,
0114         // then will just get the default precision of 6 digits.
0115         return (std::streamsize)-1;
0116     }
0117
0118     std::streamsize set_precision( std::ostream&, mpl::true_ ) { return (std::streamsize)-1; }
0119 };
0120
0121 //____________________________________________________________________________//
0122
0123 #if BOOST_WORKAROUND(BOOST_BORLANDC, BOOST_TESTED_AT(0x564))
0124 template<typename T, std::size_t N >
0125 struct print_log_value< T[N] > {
0126     void    operator()( std::ostream& ostr, T const* t )
0127     {
0128         ostr << t;
0129     }
0130 };
0131 #endif
0132
0133 //____________________________________________________________________________//
0134
0135 template<>
0136 struct BOOST_TEST_DECL print_log_value<bool> {
0137     void    operator()( std::ostream& ostr, bool t );
0138 };
0139
0140 //____________________________________________________________________________//
0141
0142 template<>
0143 struct BOOST_TEST_DECL print_log_value<char> {
0144     void    operator()( std::ostream& ostr, char t );
0145 };
0146
0147 //____________________________________________________________________________//
0148
0149 template<>
0150 struct BOOST_TEST_DECL print_log_value<unsigned char> {
0151     void    operator()( std::ostream& ostr, unsigned char t );
0152 };
0153
0154 //____________________________________________________________________________//
0155
0156 template<>
0157 struct BOOST_TEST_DECL print_log_value<wchar_t> {
0158     void    operator()( std::ostream& ostr, wchar_t t );
0159 };
0160
0161 //____________________________________________________________________________//
0162
0163 template<>
0164 struct BOOST_TEST_DECL print_log_value<char const*> {
0165     void    operator()( std::ostream& ostr, char const* t );
0166 };
0167
0168 //____________________________________________________________________________//
0169
0170 template<>
0171 struct BOOST_TEST_DECL print_log_value<wchar_t const*> {
0172     void    operator()( std::ostream& ostr, wchar_t const* t );
0173 };
0174
0175 #if !defined(BOOST_NO_CXX11_NULLPTR)
0176 template<>
0177 struct print_log_value<std::nullptr_t> {
0178     // declaration and definition is here because of #12969 https://svn.boost.org/trac10/ticket/12969
0179     void    operator()( std::ostream& ostr, std::nullptr_t /*t*/ ) {
0180         ostr << "nullptr";
0181     }
0182 };
0183 #endif
0184
0185 //____________________________________________________________________________//
0186
0187 // ************************************************************************** //
0188 // **************                 print_helper                 ************** //
0189 // ************************************************************************** //
0190 // Adds level of indirection to the output operation, allowing us to customize
0191 // it for types that do not support operator << directly or for any other reason
0192
0193 template<typename T>
0194 struct print_helper_t {
0195     explicit    print_helper_t( T const& t ) : m_t( t ) {}
0196
0197     T const&    m_t;
0198 };
0199
0200 //____________________________________________________________________________//
0201
0202 #if BOOST_WORKAROUND(BOOST_BORLANDC, BOOST_TESTED_AT(0x564))
0203 // Borland suffers premature pointer decay passing arrays by reference
0204 template<typename T, std::size_t N >
0205 struct print_helper_t< T[N] > {
0206     explicit    print_helper_t( T const * t ) : m_t( t ) {}
0207
0208     T const *   m_t;
0209 };
0210 #endif
0211
0212 //____________________________________________________________________________//
0213
0214 template<typename T>
0215 inline print_helper_t<T>
0216 print_helper( T const& t )
0217 {
0218     return print_helper_t<T>( t );
0219 }
0220
0221 //____________________________________________________________________________//
0222
0223 template<typename T>
0224 inline std::ostream&
0225 operator<<( std::ostream& ostr, print_helper_t<T> const& ph )
0226 {
0227     print_log_value<T>()( ostr, ph.m_t );
0228
0229     return ostr;
0230 }
0231
0232 //____________________________________________________________________________//
0233
0234 } // namespace tt_detail
0235
0236 // ************************************************************************** //
0237 // **************       BOOST_TEST_DONT_PRINT_LOG_VALUE        ************** //
0238 // ************************************************************************** //
0239
0240 #define BOOST_TEST_DONT_PRINT_LOG_VALUE( the_type )         \
0241 namespace boost{ namespace test_tools{ namespace tt_detail{ \
0242 template<>                                                  \
0243 struct print_log_value<the_type > {                         \
0244     void    operator()( std::ostream&, the_type const& ) {} \
0245 };                                                          \
0246 }}}                                                         \
0247 /**/
0248
0249 } // namespace test_tools
0250 } // namespace boost
0251
0252 #include <boost/test/detail/enable_warnings.hpp>
0253
0254 #endif // BOOST_TEST_TOOLS_IMPL_COMMON_HPP_012705GER