1 | // (C) Copyright John Maddock 2005.
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2 | // Use, modification and distribution are subject to the
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3 | // Boost Software License, Version 1.0. (See accompanying file
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4 | // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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5 |
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6 | #ifndef BOOST_TYPE_TRAITS_INTEGRAL_CONSTANT_HPP
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7 | #define BOOST_TYPE_TRAITS_INTEGRAL_CONSTANT_HPP
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8 |
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9 | #include <boost/config.hpp>
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10 | #include <boost/mpl/bool.hpp>
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11 | #include <boost/mpl/integral_c.hpp>
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12 |
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13 | namespace boost{
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14 |
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15 | #if defined(BOOST_NO_DEPENDENT_TYPES_IN_TEMPLATE_VALUE_PARAMETERS) || defined(__BORLANDC__)
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16 | template <class T, int val>
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17 | #else
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18 | template <class T, T val>
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19 | #endif
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20 | struct integral_constant : public mpl::integral_c<T, val>
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21 | {
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22 | //BOOST_STATIC_CONSTANT(T, value = val);
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23 | //typedef T value_type;
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24 | typedef integral_constant<T,val> type;
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25 |
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26 | #if 0
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27 | //
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28 | // everything that follows now, is MPL-compatibility code:
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29 | //
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30 | typedef ::boost::mpl::integral_c_tag tag;
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31 |
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32 | // have to #ifdef here: some compilers don't like the 'val + 1' form (MSVC),
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33 | // while some other don't like 'value + 1' (Borland), and some don't like
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34 | // either
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35 | #if BOOST_WORKAROUND(__EDG_VERSION__, <= 243)
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36 | private:
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37 | BOOST_STATIC_CONSTANT(T, next_value = BOOST_MPL_AUX_STATIC_CAST(T, (val + 1)));
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38 | BOOST_STATIC_CONSTANT(T, prior_value = BOOST_MPL_AUX_STATIC_CAST(T, (val - 1)));
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39 | public:
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40 | typedef integral_constant<T,next_value> next;
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41 | typedef integral_constant<T,prior_value> prior;
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42 | #elif BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x561)) \
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43 | || BOOST_WORKAROUND(__IBMCPP__, BOOST_TESTED_AT(502)) \
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44 | || BOOST_WORKAROUND(__HP_aCC, BOOST_TESTED_AT(53800))
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45 | typedef integral_constant<T, ( BOOST_MPL_AUX_STATIC_CAST(T, (val + 1)) )> next;
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46 | typedef integral_constant<T, ( BOOST_MPL_AUX_STATIC_CAST(T, (val - 1)) )> prior;
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47 | #else
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48 | typedef integral_constant<T, ( BOOST_MPL_AUX_STATIC_CAST(T, (value + 1)) )> next;
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49 | typedef integral_constant<T, ( BOOST_MPL_AUX_STATIC_CAST(T, (value - 1)) )> prior;
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50 | #endif
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51 |
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52 | // enables uniform function call syntax for families of overloaded
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53 | // functions that return objects of both arithmetic ('int', 'long',
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54 | // 'double', etc.) and wrapped integral types (for an example, see
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55 | // "mpl/example/power.cpp")
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56 | operator T() const { return static_cast<T>(this->value); }
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57 | #endif
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58 | };
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59 |
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60 | template<> struct integral_constant<bool,true> : public mpl::true_
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61 | {
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62 | #if BOOST_WORKAROUND(BOOST_MSVC, <= 1200)
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63 | typedef mpl::true_ base_;
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64 | using base_::value;
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65 | #endif
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66 | typedef integral_constant<bool,true> type;
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67 | };
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68 | template<> struct integral_constant<bool,false> : public mpl::false_
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69 | {
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70 | #if BOOST_WORKAROUND(BOOST_MSVC, <= 1200)
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71 | typedef mpl::false_ base_;
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72 | using base_::value;
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73 | #endif
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74 | typedef integral_constant<bool,false> type;
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75 | };
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76 |
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77 | typedef integral_constant<bool,true> true_type;
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78 | typedef integral_constant<bool,false> false_type;
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79 |
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80 | }
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81 |
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82 | #endif
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