1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/epoc32/include/stdapis/boost/numeric/conversion/detail/is_subranged.hpp Tue Mar 16 16:12:26 2010 +0000
1.3 @@ -0,0 +1,234 @@
1.4 +// © Copyright Fernando Luis Cacciola Carballal 2000-2004
1.5 +// Use, modification, and distribution is subject to the Boost Software
1.6 +// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
1.7 +// http://www.boost.org/LICENSE_1_0.txt)
1.8 +
1.9 +// See library home page at http://www.boost.org/libs/numeric/conversion
1.10 +//
1.11 +// Contact the author at: fernando_cacciola@hotmail.com
1.12 +//
1.13 +#ifndef BOOST_NUMERIC_CONVERSION_DETAIL_IS_SUBRANGED_FLC_12NOV2002_HPP
1.14 +#define BOOST_NUMERIC_CONVERSION_DETAIL_IS_SUBRANGED_FLC_12NOV2002_HPP
1.15 +
1.16 +#include "boost/config.hpp"
1.17 +#include "boost/limits.hpp"
1.18 +
1.19 +#include "boost/mpl/int.hpp"
1.20 +#include "boost/mpl/multiplies.hpp"
1.21 +#include "boost/mpl/less.hpp"
1.22 +#include "boost/mpl/equal_to.hpp"
1.23 +
1.24 +#include "boost/type_traits/is_same.hpp"
1.25 +
1.26 +#include "boost/numeric/conversion/detail/meta.hpp"
1.27 +#include "boost/numeric/conversion/detail/int_float_mixture.hpp"
1.28 +#include "boost/numeric/conversion/detail/sign_mixture.hpp"
1.29 +#include "boost/numeric/conversion/detail/udt_builtin_mixture.hpp"
1.30 +
1.31 +namespace boost { namespace numeric { namespace convdetail
1.32 +{
1.33 + //---------------------------------------------------------------
1.34 + // Implementations of the compile time predicate "T is subranged"
1.35 + //---------------------------------------------------------------
1.36 +
1.37 + // for integral to integral conversions
1.38 + template<class T,class S>
1.39 + struct subranged_Sig2Unsig
1.40 + {
1.41 + // Signed to unsigned conversions are 'subranged' because of possible loose
1.42 + // of negative values.
1.43 + typedef mpl::true_ type ;
1.44 + } ;
1.45 +
1.46 + // for unsigned integral to signed integral conversions
1.47 + template<class T,class S>
1.48 + struct subranged_Unsig2Sig
1.49 + {
1.50 + // IMPORTANT NOTE:
1.51 + //
1.52 + // This code assumes that signed/unsigned integral values are represented
1.53 + // such that:
1.54 + //
1.55 + // numeric_limits<signed T>::digits + 1 == numeric_limits<unsigned T>::digits
1.56 + //
1.57 + // The '+1' is required since numeric_limits<>::digits gives 1 bit less for signed integral types.
1.58 + //
1.59 + // This fact is used by the following logic:
1.60 + //
1.61 + // if ( (numeric_limits<T>::digits+1) < (2*numeric_limits<S>::digits) )
1.62 + // then the conversion is subranged.
1.63 + //
1.64 +
1.65 + typedef mpl::int_< ::std::numeric_limits<S>::digits > S_digits ;
1.66 + typedef mpl::int_< ::std::numeric_limits<T>::digits > T_digits ;
1.67 +
1.68 + // T is signed, so take digits+1
1.69 + typedef typename T_digits::next u_T_digits ;
1.70 +
1.71 + typedef mpl::int_<2> Two ;
1.72 +
1.73 + typedef typename mpl::multiplies<S_digits,Two>::type S_digits_times_2 ;
1.74 +
1.75 + typedef typename mpl::less<u_T_digits,S_digits_times_2>::type type ;
1.76 + } ;
1.77 +
1.78 + // for integral to integral conversions of the same sign.
1.79 + template<class T,class S>
1.80 + struct subranged_SameSign
1.81 + {
1.82 + // An integral conversion of the same sign is subranged if digits(T) < digits(S).
1.83 +
1.84 + typedef mpl::int_< ::std::numeric_limits<S>::digits > S_digits ;
1.85 + typedef mpl::int_< ::std::numeric_limits<T>::digits > T_digits ;
1.86 +
1.87 + typedef typename mpl::less<T_digits,S_digits>::type type ;
1.88 + } ;
1.89 +
1.90 + // for integral to float conversions
1.91 + template<class T,class S>
1.92 + struct subranged_Int2Float
1.93 + {
1.94 + typedef mpl::false_ type ;
1.95 + } ;
1.96 +
1.97 + // for float to integral conversions
1.98 + template<class T,class S>
1.99 + struct subranged_Float2Int
1.100 + {
1.101 + typedef mpl::true_ type ;
1.102 + } ;
1.103 +
1.104 + // for float to float conversions
1.105 + template<class T,class S>
1.106 + struct subranged_Float2Float
1.107 + {
1.108 + // If both T and S are floats,
1.109 + // compare exponent bits and if they match, mantisa bits.
1.110 +
1.111 + typedef mpl::int_< ::std::numeric_limits<S>::digits > S_mantisa ;
1.112 + typedef mpl::int_< ::std::numeric_limits<T>::digits > T_mantisa ;
1.113 +
1.114 + typedef mpl::int_< ::std::numeric_limits<S>::max_exponent > S_exponent ;
1.115 + typedef mpl::int_< ::std::numeric_limits<T>::max_exponent > T_exponent ;
1.116 +
1.117 + typedef typename mpl::less<T_exponent,S_exponent>::type T_smaller_exponent ;
1.118 +
1.119 + typedef typename mpl::equal_to<T_exponent,S_exponent>::type equal_exponents ;
1.120 +
1.121 + typedef mpl::less<T_mantisa,S_mantisa> T_smaller_mantisa ;
1.122 +
1.123 + typedef mpl::eval_if<equal_exponents,T_smaller_mantisa,mpl::false_> not_bigger_exponent_case ;
1.124 +
1.125 + typedef typename
1.126 + mpl::eval_if<T_smaller_exponent,mpl::true_,not_bigger_exponent_case>::type
1.127 + type ;
1.128 + } ;
1.129 +
1.130 + // for Udt to built-in conversions
1.131 + template<class T,class S>
1.132 + struct subranged_Udt2BuiltIn
1.133 + {
1.134 + typedef mpl::true_ type ;
1.135 + } ;
1.136 +
1.137 + // for built-in to Udt conversions
1.138 + template<class T,class S>
1.139 + struct subranged_BuiltIn2Udt
1.140 + {
1.141 + typedef mpl::false_ type ;
1.142 + } ;
1.143 +
1.144 + // for Udt to Udt conversions
1.145 + template<class T,class S>
1.146 + struct subranged_Udt2Udt
1.147 + {
1.148 + typedef mpl::false_ type ;
1.149 + } ;
1.150 +
1.151 + //-------------------------------------------------------------------
1.152 + // Selectors for the implementations of the subranged predicate
1.153 + //-------------------------------------------------------------------
1.154 +
1.155 + template<class T,class S>
1.156 + struct get_subranged_Int2Int
1.157 + {
1.158 + typedef subranged_SameSign<T,S> Sig2Sig ;
1.159 + typedef subranged_Sig2Unsig<T,S> Sig2Unsig ;
1.160 + typedef subranged_Unsig2Sig<T,S> Unsig2Sig ;
1.161 + typedef Sig2Sig Unsig2Unsig ;
1.162 +
1.163 + typedef typename get_sign_mixture<T,S>::type sign_mixture ;
1.164 +
1.165 + typedef typename
1.166 + for_sign_mixture<sign_mixture, Sig2Sig, Sig2Unsig, Unsig2Sig, Unsig2Unsig>::type
1.167 + type ;
1.168 + } ;
1.169 +
1.170 + template<class T,class S>
1.171 + struct get_subranged_BuiltIn2BuiltIn
1.172 + {
1.173 + typedef get_subranged_Int2Int<T,S> Int2IntQ ;
1.174 +
1.175 + typedef subranged_Int2Float <T,S> Int2Float ;
1.176 + typedef subranged_Float2Int <T,S> Float2Int ;
1.177 + typedef subranged_Float2Float<T,S> Float2Float ;
1.178 +
1.179 + typedef mpl::identity<Int2Float > Int2FloatQ ;
1.180 + typedef mpl::identity<Float2Int > Float2IntQ ;
1.181 + typedef mpl::identity<Float2Float> Float2FloatQ ;
1.182 +
1.183 + typedef typename get_int_float_mixture<T,S>::type int_float_mixture ;
1.184 +
1.185 + typedef for_int_float_mixture<int_float_mixture, Int2IntQ, Int2FloatQ, Float2IntQ, Float2FloatQ> for_ ;
1.186 +
1.187 + typedef typename for_::type selected ;
1.188 +
1.189 + typedef typename selected::type type ;
1.190 + } ;
1.191 +
1.192 + template<class T,class S>
1.193 + struct get_subranged
1.194 + {
1.195 + typedef get_subranged_BuiltIn2BuiltIn<T,S> BuiltIn2BuiltInQ ;
1.196 +
1.197 + typedef subranged_BuiltIn2Udt<T,S> BuiltIn2Udt ;
1.198 + typedef subranged_Udt2BuiltIn<T,S> Udt2BuiltIn ;
1.199 + typedef subranged_Udt2Udt<T,S> Udt2Udt ;
1.200 +
1.201 + typedef mpl::identity<BuiltIn2Udt> BuiltIn2UdtQ ;
1.202 + typedef mpl::identity<Udt2BuiltIn> Udt2BuiltInQ ;
1.203 + typedef mpl::identity<Udt2Udt > Udt2UdtQ ;
1.204 +
1.205 + typedef typename get_udt_builtin_mixture<T,S>::type udt_builtin_mixture ;
1.206 +
1.207 + typedef typename
1.208 + for_udt_builtin_mixture<udt_builtin_mixture, BuiltIn2BuiltInQ, BuiltIn2UdtQ, Udt2BuiltInQ, Udt2UdtQ>::type
1.209 + selected ;
1.210 +
1.211 + typedef typename selected::type selected2 ;
1.212 +
1.213 + typedef typename selected2::type type ;
1.214 + } ;
1.215 +
1.216 +
1.217 + //-------------------------------------------------------------------
1.218 + // Top level implementation selector.
1.219 + //-------------------------------------------------------------------
1.220 + template<class T, class S>
1.221 + struct get_is_subranged
1.222 + {
1.223 + typedef get_subranged<T,S> non_trivial_case ;
1.224 + typedef mpl::identity<mpl::false_> trivial_case ;
1.225 +
1.226 + typedef is_same<T,S> is_trivial ;
1.227 +
1.228 + typedef typename mpl::if_<is_trivial,trivial_case,non_trivial_case>::type selected ;
1.229 +
1.230 + typedef typename selected::type type ;
1.231 + } ;
1.232 +
1.233 +} } } // namespace boost::numeric::convdetail
1.234 +
1.235 +#endif
1.236 +
1.237 +