ceph/src/boost/libs/log/include/boost/log/utility/functional/logical.hpp

   1 /*
   2  *          Copyright Andrey Semashev 2007 - 2015.
   3  * Distributed under the Boost Software License, Version 1.0.
   4  *    (See accompanying file LICENSE_1_0.txt or copy at
   5  *          http://www.boost.org/LICENSE_1_0.txt)
   6  */
   7 /*!
   8  * \file   logical.hpp
   9  * \author Andrey Semashev
  10  * \date   30.03.2008
  11  *
  12  * This header contains logical predicates for value comparison, analogous to \c std::less, \c std::greater
  13  * and others. The main difference from the standard equivalents is that the predicates defined in this
  14  * header are not templates and therefore do not require a fixed argument type. Furthermore, both arguments
  15  * may have different types, in which case the comparison is performed without type conversion.
  16  *
  17  * \note In case if arguments are integral, the conversion is performed according to the standard C++ rules
  18  *       in order to avoid warnings from the compiler.
  19  */
  20
  21 #ifndef BOOST_LOG_UTILITY_FUNCTIONAL_LOGICAL_HPP_INCLUDED_
  22 #define BOOST_LOG_UTILITY_FUNCTIONAL_LOGICAL_HPP_INCLUDED_
  23
  24 #include <boost/mpl/if.hpp>
  25 #include <boost/mpl/bool.hpp>
  26 #include <boost/mpl/and.hpp>
  27 #include <boost/type_traits/is_integral.hpp>
  28 #include <boost/type_traits/is_unsigned.hpp>
  29 #include <boost/log/detail/config.hpp>
  30 #include <boost/log/detail/header.hpp>
  31
  32 #ifdef BOOST_HAS_PRAGMA_ONCE
  33 #pragma once
  34 #endif
  35
  36 namespace boost {
  37
  38 BOOST_LOG_OPEN_NAMESPACE
  39
  40 namespace aux {
  41
  42 //! The trait creates a common integral type suitable for comparison. This is mostly to silence compiler warnings like 'signed/unsigned mismatch'.
  43 template< typename T, typename U, unsigned int TSizeV = sizeof(T), unsigned int USizeV = sizeof(U), bool TSmallerThanU = (sizeof(T) < sizeof(U)) >
  44 struct make_common_integral_type
  45 {
  46     typedef T type;
  47 };
  48
  49 //! Specialization for case when \c T is smaller than \c U
  50 template< typename T, typename U, unsigned int TSizeV, unsigned int USizeV >
  51 struct make_common_integral_type< T, U, TSizeV, USizeV, true >
  52 {
  53     typedef U type;
  54 };
  55
  56 //! Specialization for the case when both types have the same size
  57 template< typename T, typename U, unsigned int SizeV >
  58 struct make_common_integral_type< T, U, SizeV, SizeV, false > :
  59     public mpl::if_<
  60         is_unsigned< T >,
  61         T,
  62         U
  63     >
  64 {
  65 };
  66
  67 } // namespace aux
  68
  69 //! Equality predicate
  70 struct equal_to
  71 {
  72     typedef bool result_type;
  73
  74     template< typename T, typename U >
  75     bool operator() (T const& left, U const& right) const
  76     {
  77         return op(left, right, typename mpl::and_< is_integral< T >, is_integral< U > >::type());
  78     }
  79
  80 private:
  81     template< typename T, typename U >
  82     static bool op(T const& left, U const& right, mpl::false_ const&)
  83     {
  84         return (left == right);
  85     }
  86     template< typename T, typename U >
  87     static bool op(T const& left, U const& right, mpl::true_ const&)
  88     {
  89         typedef typename aux::make_common_integral_type< T, U >::type common_integral_type;
  90         return static_cast< common_integral_type >(left) == static_cast< common_integral_type >(right);
  91     }
  92 };
  93
  94 //! Inequality predicate
  95 struct not_equal_to
  96 {
  97     typedef bool result_type;
  98
  99     template< typename T, typename U >
 100     bool operator() (T const& left, U const& right) const
 101     {
 102         return op(left, right, typename mpl::and_< is_integral< T >, is_integral< U > >::type());
 103     }
 104
 105 private:
 106     template< typename T, typename U >
 107     static bool op(T const& left, U const& right, mpl::false_ const&)
 108     {
 109         return (left != right);
 110     }
 111     template< typename T, typename U >
 112     static bool op(T const& left, U const& right, mpl::true_ const&)
 113     {
 114         typedef typename aux::make_common_integral_type< T, U >::type common_integral_type;
 115         return static_cast< common_integral_type >(left) != static_cast< common_integral_type >(right);
 116     }
 117 };
 118
 119 //! Less predicate
 120 struct less
 121 {
 122     typedef bool result_type;
 123
 124     template< typename T, typename U >
 125     bool operator() (T const& left, U const& right) const
 126     {
 127         return op(left, right, typename mpl::and_< is_integral< T >, is_integral< U > >::type());
 128     }
 129
 130 private:
 131     template< typename T, typename U >
 132     static bool op(T const& left, U const& right, mpl::false_ const&)
 133     {
 134         return (left < right);
 135     }
 136     template< typename T, typename U >
 137     static bool op(T const& left, U const& right, mpl::true_ const&)
 138     {
 139         typedef typename aux::make_common_integral_type< T, U >::type common_integral_type;
 140         return static_cast< common_integral_type >(left) < static_cast< common_integral_type >(right);
 141     }
 142 };
 143
 144 //! Greater predicate
 145 struct greater
 146 {
 147     typedef bool result_type;
 148
 149     template< typename T, typename U >
 150     bool operator() (T const& left, U const& right) const
 151     {
 152         return op(left, right, typename mpl::and_< is_integral< T >, is_integral< U > >::type());
 153     }
 154
 155 private:
 156     template< typename T, typename U >
 157     static bool op(T const& left, U const& right, mpl::false_ const&)
 158     {
 159         return (left > right);
 160     }
 161     template< typename T, typename U >
 162     static bool op(T const& left, U const& right, mpl::true_ const&)
 163     {
 164         typedef typename aux::make_common_integral_type< T, U >::type common_integral_type;
 165         return static_cast< common_integral_type >(left) > static_cast< common_integral_type >(right);
 166     }
 167 };
 168
 169 //! Less or equal predicate
 170 struct less_equal
 171 {
 172     typedef bool result_type;
 173
 174     template< typename T, typename U >
 175     bool operator() (T const& left, U const& right) const
 176     {
 177         return op(left, right, typename mpl::and_< is_integral< T >, is_integral< U > >::type());
 178     }
 179
 180 private:
 181     template< typename T, typename U >
 182     static bool op(T const& left, U const& right, mpl::false_ const&)
 183     {
 184         return (left <= right);
 185     }
 186     template< typename T, typename U >
 187     static bool op(T const& left, U const& right, mpl::true_ const&)
 188     {
 189         typedef typename aux::make_common_integral_type< T, U >::type common_integral_type;
 190         return static_cast< common_integral_type >(left) <= static_cast< common_integral_type >(right);
 191     }
 192 };
 193
 194 //! Greater or equal predicate
 195 struct greater_equal
 196 {
 197     typedef bool result_type;
 198
 199     template< typename T, typename U >
 200     bool operator() (T const& left, U const& right) const
 201     {
 202         return op(left, right, typename mpl::and_< is_integral< T >, is_integral< U > >::type());
 203     }
 204
 205 private:
 206     template< typename T, typename U >
 207     static bool op(T const& left, U const& right, mpl::false_ const&)
 208     {
 209         return (left >= right);
 210     }
 211     template< typename T, typename U >
 212     static bool op(T const& left, U const& right, mpl::true_ const&)
 213     {
 214         typedef typename aux::make_common_integral_type< T, U >::type common_integral_type;
 215         return static_cast< common_integral_type >(left) >= static_cast< common_integral_type >(right);
 216     }
 217 };
 218
 219 BOOST_LOG_CLOSE_NAMESPACE // namespace log
 220
 221 } // namespace boost
 222
 223 #include <boost/log/detail/footer.hpp>
 224
 225 #endif // BOOST_LOG_UTILITY_FUNCTIONAL_LOGICAL_HPP_INCLUDED_