ceph/src/boost/boost/numeric/conversion/detail/sign_mixture.hpp

   1 //  (c) Copyright Fernando Luis Cacciola Carballal 2000-2004
   2 //  Use, modification, and distribution is subject to the Boost Software
   3 //  License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
   4 //  http://www.boost.org/LICENSE_1_0.txt)
   5
   6 //  See library home page at http://www.boost.org/libs/numeric/conversion
   7 //
   8 // Contact the author at: fernando_cacciola@hotmail.com
   9 //
  10 #ifndef BOOST_NUMERIC_CONVERSION_DETAIL_SIGN_MIXTURE_FLC_12NOV2002_HPP
  11 #define BOOST_NUMERIC_CONVERSION_DETAIL_SIGN_MIXTURE_FLC_12NOV2002_HPP
  12
  13 #include "boost/config.hpp"
  14 #include "boost/limits.hpp"
  15
  16 #include "boost/numeric/conversion/sign_mixture_enum.hpp"
  17 #include "boost/numeric/conversion/detail/meta.hpp"
  18
  19 #include "boost/mpl/integral_c.hpp"
  20
  21 namespace boost { namespace numeric { namespace convdetail
  22 {
  23   // Integral Constants for 'SignMixture'
  24   typedef mpl::integral_c<sign_mixture_enum, unsigned_to_unsigned> unsig2unsig_c ;
  25   typedef mpl::integral_c<sign_mixture_enum, signed_to_signed>     sig2sig_c ;
  26   typedef mpl::integral_c<sign_mixture_enum, signed_to_unsigned>   sig2unsig_c ;
  27   typedef mpl::integral_c<sign_mixture_enum, unsigned_to_signed>   unsig2sig_c ;
  28
  29   // Metafunction:
  30   //
  31   //   get_sign_mixture<T,S>::type
  32   //
  33   // Selects the appropriate SignMixture Integral Constant for the combination T,S.
  34   //
  35   template<class T,class S>
  36   struct get_sign_mixture
  37   {
  38     typedef mpl::bool_< ::std::numeric_limits<S>::is_signed > S_signed ;
  39     typedef mpl::bool_< ::std::numeric_limits<T>::is_signed > T_signed ;
  40
  41     typedef typename
  42       for_both<S_signed, T_signed, sig2sig_c, sig2unsig_c, unsig2sig_c, unsig2unsig_c>::type
  43         type ;
  44   } ;
  45
  46   // Metafunction:
  47   //
  48   //   for_sign_mixture<SignMixture,Sig2Sig,Sig2Unsig,Unsig2Sig,Unsig2Unsig>::type
  49   //
  50   // {SignMixture} is one of the Integral Constants for SignMixture, declared above.
  51   // {Sig2Sig,Sig2Unsig,Unsig2Sig,Unsig2Unsig} are aribtrary types. (not metafunctions)
  52   //
  53   // According to the value of 'SignMixture', selects the corresponding type.
  54   //
  55   template<class SignMixture, class Sig2Sig, class Sig2Unsig, class Unsig2Sig, class Unsig2Unsig>
  56   struct for_sign_mixture
  57   {
  58     typedef typename
  59       ct_switch4<SignMixture
  60                  , sig2sig_c, sig2unsig_c, unsig2sig_c  // default
  61                  , Sig2Sig  , Sig2Unsig  , Unsig2Sig  , Unsig2Unsig
  62                 >::type
  63         type ;
  64   } ;
  65
  66 } } } // namespace boost::numeric::convdetail
  67
  68 #endif
  69 //
  70 ///////////////////////////////////////////////////////////////////////////////////////////////
  71
  72