ceph/src/boost/libs/lambda/include/boost/lambda/detail/arity_code.hpp

   1 // -- Boost Lambda Library -------------------------------------------------
   2
   3 // Copyright (C) 1999, 2000 Jaakko Jarvi (jaakko.jarvi@cs.utu.fi)
   4 //
   5 // Distributed under the Boost Software License, Version 1.0. (See
   6 // accompanying file LICENSE_1_0.txt or copy at
   7 // http://www.boost.org/LICENSE_1_0.txt)
   8 //
   9 // For more information, see www.boost.org
  10
  11 // --------------------------------------------------
  12
  13 #ifndef BOOST_LAMBDA_ARITY_CODE_HPP
  14 #define BOOST_LAMBDA_ARITY_CODE_HPP
  15
  16 #include "boost/type_traits/cv_traits.hpp"
  17 #include "boost/type_traits/transform_traits.hpp"
  18
  19 namespace boost {
  20 namespace lambda {
  21
  22 // These constants state, whether a lambda_functor instantiation results from
  23 // an expression which contains no placeholders (NONE),
  24 // only free1 placeholders (FIRST),
  25 // free2 placeholders and maybe free1 placeholders (SECOND),
  26 // free3 and maybe free1 and free2 placeholders (THIRD),
  27 // freeE placeholders and maybe free1 and free2  (EXCEPTION).
  28 // RETHROW means, that a rethrow expression is used somewhere in the lambda_functor.
  29
  30 enum { NONE             = 0x00, // Notice we are using bits as flags here.
  31        FIRST            = 0x01,
  32        SECOND           = 0x02,
  33        THIRD            = 0x04,
  34        EXCEPTION        = 0x08,
  35        RETHROW          = 0x10};
  36
  37
  38 template<class T>
  39 struct get_tuple_arity;
  40
  41 namespace detail {
  42
  43 template <class T> struct get_arity_;
  44
  45 } // end detail;
  46
  47 template <class T> struct get_arity {
  48
  49   BOOST_STATIC_CONSTANT(int, value = detail::get_arity_<typename boost::remove_cv<typename boost::remove_reference<T>::type>::type>::value);
  50
  51 };
  52
  53 namespace detail {
  54
  55 template<class T>
  56 struct get_arity_ {
  57   BOOST_STATIC_CONSTANT(int, value = 0);
  58 };
  59
  60 template<class T>
  61 struct get_arity_<lambda_functor<T> > {
  62   BOOST_STATIC_CONSTANT(int, value = get_arity<T>::value);
  63 };
  64
  65 template<class Action, class Args>
  66 struct get_arity_<lambda_functor_base<Action, Args> > {
  67   BOOST_STATIC_CONSTANT(int, value = get_tuple_arity<Args>::value);
  68 };
  69
  70 template<int I>
  71 struct get_arity_<placeholder<I> > {
  72   BOOST_STATIC_CONSTANT(int, value = I);
  73 };
  74
  75 } // detail
  76
  77 template<class T>
  78 struct get_tuple_arity {
  79   BOOST_STATIC_CONSTANT(int, value = get_arity<typename T::head_type>::value | get_tuple_arity<typename T::tail_type>::value);
  80 };
  81
  82
  83 template<>
  84 struct get_tuple_arity<null_type> {
  85   BOOST_STATIC_CONSTANT(int, value = 0);
  86 };
  87
  88
  89   // Does T have placeholder<I> as it's subexpression?
  90
  91 template<class T, int I>
  92 struct has_placeholder {
  93   BOOST_STATIC_CONSTANT(bool, value = (get_arity<T>::value & I) != 0);
  94 };
  95
  96 template<int I, int J>
  97 struct includes_placeholder {
  98   BOOST_STATIC_CONSTANT(bool, value = (J & I) != 0);
  99 };
 100
 101 template<int I, int J>
 102 struct lacks_placeholder {
 103   BOOST_STATIC_CONSTANT(bool, value = ((J & I) == 0));
 104 };
 105
 106
 107 } // namespace lambda
 108 } // namespace boost
 109
 110 #endif