boost/type_traits/make_signed.hpp

0001
0002 //  (C) Copyright John Maddock 2007.
0003 //  Use, modification and distribution are subject to the Boost Software License,
0004 //  Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
0005 //  http://www.boost.org/LICENSE_1_0.txt).
0006 //
0007 //  See http://www.boost.org/libs/type_traits for most recent version including documentation.
0008
0009 #ifndef BOOST_TT_MAKE_SIGNED_HPP_INCLUDED
0010 #define BOOST_TT_MAKE_SIGNED_HPP_INCLUDED
0011
0012 #include <boost/type_traits/conditional.hpp>
0013 #include <boost/type_traits/is_integral.hpp>
0014 #include <boost/type_traits/is_signed.hpp>
0015 #include <boost/type_traits/is_unsigned.hpp>
0016 #include <boost/type_traits/is_enum.hpp>
0017 #include <boost/type_traits/is_same.hpp>
0018 #include <boost/type_traits/remove_cv.hpp>
0019 #include <boost/type_traits/is_const.hpp>
0020 #include <boost/type_traits/is_volatile.hpp>
0021 #include <boost/type_traits/add_const.hpp>
0022 #include <boost/type_traits/add_volatile.hpp>
0023 #include <boost/static_assert.hpp>
0024
0025 namespace boost {
0026
0027 template <class T>
0028 struct make_signed
0029 {
0030 private:
0031    BOOST_STATIC_ASSERT_MSG(( ::boost::is_integral<T>::value || ::boost::is_enum<T>::value), "The template argument to make_signed must be an integer or enum type.");
0032    BOOST_STATIC_ASSERT_MSG(!(::boost::is_same<typename remove_cv<T>::type, bool>::value), "The template argument to make_signed must not be the type bool.");
0033
0034    typedef typename remove_cv<T>::type t_no_cv;
0035    typedef typename conditional<
0036       (::boost::is_signed<T>::value
0037       && ::boost::is_integral<T>::value
0038       && ! ::boost::is_same<t_no_cv, char>::value
0039       && ! ::boost::is_same<t_no_cv, wchar_t>::value
0040       && ! ::boost::is_same<t_no_cv, bool>::value),
0041       T,
0042       typename conditional<
0043          (::boost::is_integral<T>::value
0044          && ! ::boost::is_same<t_no_cv, char>::value
0045          && ! ::boost::is_same<t_no_cv, wchar_t>::value
0046          && ! ::boost::is_same<t_no_cv, bool>::value),
0047          typename conditional<
0048             is_same<t_no_cv, unsigned char>::value,
0049             signed char,
0050             typename conditional<
0051                is_same<t_no_cv, unsigned short>::value,
0052                signed short,
0053                typename conditional<
0054                   is_same<t_no_cv, unsigned int>::value,
0055                   int,
0056                   typename conditional<
0057                      is_same<t_no_cv, unsigned long>::value,
0058                      long,
0059 #if defined(BOOST_HAS_LONG_LONG)
0060 #ifdef BOOST_HAS_INT128
0061                      typename conditional<
0062                         sizeof(t_no_cv) == sizeof(boost::long_long_type),
0063                         boost::long_long_type,
0064                         boost::int128_type
0065                      >::type
0066 #else
0067                      boost::long_long_type
0068 #endif
0069 #elif defined(BOOST_HAS_MS_INT64)
0070                      __int64
0071 #else
0072                      long
0073 #endif
0074                   >::type
0075                >::type
0076             >::type
0077          >::type,
0078          // Not a regular integer type:
0079          typename conditional<
0080             sizeof(t_no_cv) == sizeof(unsigned char),
0081             signed char,
0082             typename conditional<
0083                sizeof(t_no_cv) == sizeof(unsigned short),
0084                signed short,
0085                typename conditional<
0086                   sizeof(t_no_cv) == sizeof(unsigned int),
0087                   int,
0088                   typename conditional<
0089                      sizeof(t_no_cv) == sizeof(unsigned long),
0090                      long,
0091 #if defined(BOOST_HAS_LONG_LONG)
0092 #ifdef BOOST_HAS_INT128
0093                      typename conditional<
0094                         sizeof(t_no_cv) == sizeof(boost::long_long_type),
0095                         boost::long_long_type,
0096                         boost::int128_type
0097                      >::type
0098 #else
0099                      boost::long_long_type
0100 #endif
0101 #elif defined(BOOST_HAS_MS_INT64)
0102                      __int64
0103 #else
0104                      long
0105 #endif
0106                   >::type
0107                >::type
0108             >::type
0109          >::type
0110       >::type
0111    >::type base_integer_type;
0112
0113    // Add back any const qualifier:
0114    typedef typename conditional<
0115       is_const<T>::value,
0116       typename add_const<base_integer_type>::type,
0117       base_integer_type
0118    >::type const_base_integer_type;
0119 public:
0120    // Add back any volatile qualifier:
0121    typedef typename conditional<
0122       is_volatile<T>::value,
0123       typename add_volatile<const_base_integer_type>::type,
0124       const_base_integer_type
0125    >::type type;
0126 };
0127
0128 #if !defined(BOOST_NO_CXX11_TEMPLATE_ALIASES)
0129
0130    template <class T> using make_signed_t = typename make_signed<T>::type;
0131
0132 #endif
0133
0134 } // namespace boost
0135
0136 #endif // BOOST_TT_ADD_REFERENCE_HPP_INCLUDED
0137