1 |
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2 | // (C) Copyright John Maddock 2000.
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3 | // Use, modification and distribution are subject to the Boost Software License,
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4 | // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
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5 | // http://www.boost.org/LICENSE_1_0.txt).
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6 | //
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7 | // See http://www.boost.org/libs/type_traits for most recent version including documentation.
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8 |
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9 | #ifndef BOOST_TT_ALIGNMENT_OF_HPP_INCLUDED
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10 | #define BOOST_TT_ALIGNMENT_OF_HPP_INCLUDED
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11 |
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12 | #include "boost/config.hpp"
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13 | #include <cstddef>
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14 |
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15 | // should be the last #include
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16 | #include "boost/type_traits/detail/size_t_trait_def.hpp"
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17 |
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18 | #ifdef BOOST_MSVC
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19 | # pragma warning(push)
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20 | # pragma warning(disable: 4121) // alignment is sensitive to packing
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21 | #endif
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22 | #if defined(__BORLANDC__) && (__BORLANDC__ < 0x600)
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23 | #pragma option push -Vx- -Ve-
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24 | #endif
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25 |
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26 | namespace boost {
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27 |
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28 | template <typename T> struct alignment_of;
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29 |
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30 | // get the alignment of some arbitrary type:
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31 | namespace detail {
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32 |
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33 | template <typename T>
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34 | struct alignment_of_hack
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35 | {
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36 | char c;
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37 | T t;
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38 | alignment_of_hack();
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39 | };
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40 |
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41 |
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42 | template <unsigned A, unsigned S>
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43 | struct alignment_logic
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44 | {
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45 | BOOST_STATIC_CONSTANT(std::size_t, value = A < S ? A : S);
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46 | };
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47 |
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48 |
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49 | template< typename T >
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50 | struct alignment_of_impl
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51 | {
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52 | BOOST_STATIC_CONSTANT(std::size_t, value =
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53 | (::boost::detail::alignment_logic<
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54 | sizeof(detail::alignment_of_hack<T>) - sizeof(T),
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55 | sizeof(T)
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56 | >::value));
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57 | };
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58 |
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59 | } // namespace detail
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60 |
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61 | BOOST_TT_AUX_SIZE_T_TRAIT_DEF1(alignment_of,T,::boost::detail::alignment_of_impl<T>::value)
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62 |
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63 | // references have to be treated specially, assume
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64 | // that a reference is just a special pointer:
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65 | #ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
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66 | template <typename T>
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67 | struct alignment_of<T&>
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68 | : alignment_of<T*>
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69 | {
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70 | };
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71 | #endif
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72 | #ifdef __BORLANDC__
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73 | // long double gives an incorrect value of 10 (!)
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74 | // unless we do this...
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75 | struct long_double_wrapper{ long double ld; };
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76 | template<> struct alignment_of<long double>
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77 | : public alignment_of<long_double_wrapper>{};
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78 | #endif
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79 |
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80 | // void has to be treated specially:
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81 | BOOST_TT_AUX_SIZE_T_TRAIT_SPEC1(alignment_of,void,0)
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82 | #ifndef BOOST_NO_CV_VOID_SPECIALIZATIONS
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83 | BOOST_TT_AUX_SIZE_T_TRAIT_SPEC1(alignment_of,void const,0)
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84 | BOOST_TT_AUX_SIZE_T_TRAIT_SPEC1(alignment_of,void volatile,0)
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85 | BOOST_TT_AUX_SIZE_T_TRAIT_SPEC1(alignment_of,void const volatile,0)
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86 | #endif
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87 |
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88 | } // namespace boost
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89 |
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90 | #if defined(__BORLANDC__) && (__BORLANDC__ < 0x600)
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91 | #pragma option pop
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92 | #endif
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93 | #ifdef BOOST_MSVC
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94 | # pragma warning(pop)
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95 | #endif
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96 |
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97 | #include "boost/type_traits/detail/size_t_trait_undef.hpp"
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98 |
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99 | #endif // BOOST_TT_ALIGNMENT_OF_HPP_INCLUDED
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100 |
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