ceph/src/boost/libs/units/include/boost/units/detail/heterogeneous_conversion.hpp

   1 // Boost.Units - A C++ library for zero-overhead dimensional analysis and
   2 // unit/quantity manipulation and conversion
   3 //
   4 // Copyright (C) 2003-2008 Matthias Christian Schabel
   5 // Copyright (C) 2008 Steven Watanabe
   6 //
   7 // Distributed under the Boost Software License, Version 1.0. (See
   8 // accompanying file LICENSE_1_0.txt or copy at
   9 // http://www.boost.org/LICENSE_1_0.txt)
  10
  11 #ifndef BOOST_UNITS_DETAIL_HETEROGENEOUS_CONVERSION_HPP
  12 #define BOOST_UNITS_DETAIL_HETEROGENEOUS_CONVERSION_HPP
  13
  14 #include <boost/mpl/minus.hpp>
  15 #include <boost/mpl/times.hpp>
  16
  17 #include <boost/units/static_rational.hpp>
  18 #include <boost/units/homogeneous_system.hpp>
  19 #include <boost/units/detail/linear_algebra.hpp>
  20
  21 namespace boost {
  22
  23 namespace units {
  24
  25 namespace detail {
  26
  27 struct solve_end {
  28     template<class Begin, class Y>
  29     struct apply {
  30         typedef dimensionless_type type;
  31     };
  32 };
  33
  34 struct no_solution {};
  35
  36 template<class X1, class X2, class Next>
  37 struct solve_normal {
  38     template<class Begin, class Y>
  39     struct apply {
  40         typedef typename Begin::next next;
  41         typedef list<
  42             typename mpl::minus<
  43                 typename mpl::times<X1, Y>::type,
  44                 typename mpl::times<X2, typename Begin::item>::type
  45             >::type,
  46             typename Next::template apply<next, Y>::type
  47         > type;
  48     };
  49 };
  50
  51 template<class Next>
  52 struct solve_leading_zeroes {
  53     template<class Begin>
  54     struct apply {
  55         typedef list<
  56             typename Begin::item,
  57             typename Next::template apply<typename Begin::next>::type
  58         > type;
  59     };
  60     typedef solve_leading_zeroes type;
  61 };
  62
  63 template<>
  64 struct solve_leading_zeroes<no_solution> {
  65     typedef no_solution type;
  66 };
  67
  68 template<class Next>
  69 struct solve_first_non_zero {
  70     template<class Begin>
  71     struct apply {
  72         typedef typename Next::template apply<
  73             typename Begin::next,
  74             typename Begin::item
  75         >::type type;
  76     };
  77 };
  78
  79 template<class Next>
  80 struct solve_internal_zero {
  81     template<class Begin, class Y>
  82     struct apply {
  83         typedef list<
  84             typename Begin::item,
  85             typename Next::template apply<typename Begin::next, Y>::type
  86         > type;
  87     };
  88 };
  89
  90 template<class T>
  91 struct make_solve_list_internal_zero {
  92     template<class Next, class X>
  93     struct apply {
  94         typedef solve_normal<T, X, Next> type;
  95     };
  96 };
  97
  98 template<>
  99 struct make_solve_list_internal_zero<static_rational<0> > {
 100     template<class Next, class X>
 101     struct apply {
 102         typedef solve_internal_zero<Next> type;
 103     };
 104 };
 105
 106 template<int N>
 107 struct make_solve_list_normal {
 108     template<class Begin, class X>
 109     struct apply {
 110         typedef typename make_solve_list_internal_zero<
 111             typename Begin::item
 112         >::template apply<
 113             typename make_solve_list_normal<N-1>::template apply<typename Begin::next, X>::type,
 114             X
 115         >::type type;
 116     };
 117 };
 118
 119 template<>
 120 struct make_solve_list_normal<0> {
 121     template<class Begin, class X>
 122     struct apply {
 123         typedef solve_end type;
 124     };
 125 };
 126
 127 template<int N>
 128 struct make_solve_list_leading_zeroes;
 129
 130 template<class T>
 131 struct make_solve_list_first_non_zero {
 132     template<class Begin, int N>
 133     struct apply {
 134         typedef solve_first_non_zero<
 135             typename make_solve_list_normal<N-1>::template apply<
 136                 typename Begin::next,
 137                 typename Begin::item
 138             >::type
 139         > type;
 140     };
 141 };
 142
 143 template<>
 144 struct make_solve_list_first_non_zero<static_rational<0> > {
 145     template<class Begin, int N>
 146     struct apply {
 147         typedef typename solve_leading_zeroes<
 148             typename make_solve_list_leading_zeroes<N-1>::template apply<
 149                 typename Begin::next
 150             >::type
 151         >::type type;
 152     };
 153 };
 154
 155 template<int N>
 156 struct make_solve_list_leading_zeroes {
 157     template<class Begin>
 158     struct apply {
 159         typedef typename make_solve_list_first_non_zero<typename Begin::item>::template apply<Begin, N>::type type;
 160     };
 161 };
 162
 163 template<>
 164 struct make_solve_list_leading_zeroes<0> {
 165     template<class Begin>
 166     struct apply {
 167         typedef no_solution type;
 168     };
 169 };
 170
 171 template<int N>
 172 struct try_add_unit_impl {
 173     template<class Begin, class L>
 174     struct apply {
 175         typedef typename try_add_unit_impl<N-1>::template apply<typename Begin::next, L>::type next;
 176         typedef typename Begin::item::template apply<next>::type type;
 177         BOOST_STATIC_ASSERT((next::size::value - 1 == type::size::value));
 178     };
 179 };
 180
 181 template<>
 182 struct try_add_unit_impl<0> {
 183     template<class Begin, class L>
 184     struct apply {
 185         typedef L type;
 186     };
 187 };
 188
 189 template<int N>
 190 struct make_homogeneous_system_impl;
 191
 192 template<class T, bool is_done>
 193 struct make_homogeneous_system_func;
 194
 195 template<class T>
 196 struct make_homogeneous_system_func<T, false> {
 197     template<class Begin, class Current, class Units, class Dimensions, int N>
 198     struct apply {
 199         typedef typename make_homogeneous_system_impl<N-1>::template apply<
 200             typename Begin::next,
 201             list<T, Current>,
 202             list<typename Begin::item, Units>,
 203             Dimensions
 204         >::type type;
 205     };
 206 };
 207
 208 template<class T>
 209 struct make_homogeneous_system_func<T, true> {
 210     template<class Begin, class Current, class Units, class Dimensions, int N>
 211     struct apply {
 212         typedef list<typename Begin::item, Units> type;
 213     };
 214 };
 215
 216 template<>
 217 struct make_homogeneous_system_func<no_solution, false> {
 218     template<class Begin, class Current, class Units, class Dimensions, int N>
 219     struct apply {
 220         typedef typename make_homogeneous_system_impl<N-1>::template apply<
 221             typename Begin::next,
 222             Current,
 223             Units,
 224             Dimensions
 225         >::type type;
 226     };
 227 };
 228
 229 template<>
 230 struct make_homogeneous_system_func<no_solution, true> {
 231     template<class Begin, class Current, class Units, class Dimensions, int N>
 232     struct apply {
 233         typedef typename make_homogeneous_system_impl<N-1>::template apply<
 234             typename Begin::next,
 235             Current,
 236             Units,
 237             Dimensions
 238         >::type type;
 239     };
 240 };
 241
 242 template<int N>
 243 struct make_homogeneous_system_impl {
 244     template<class Begin, class Current, class Units, class Dimensions>
 245     struct apply {
 246         typedef typename expand_dimensions<Dimensions::size::value>::template apply<
 247             Dimensions,
 248             typename Begin::item::dimension_type
 249         >::type dimensions;
 250         typedef typename try_add_unit_impl<Current::size::value>::template apply<Current, dimensions>::type new_element;
 251         typedef typename make_solve_list_leading_zeroes<new_element::size::value>::template apply<new_element>::type new_func;
 252         typedef typename make_homogeneous_system_func<
 253             new_func,
 254             ((Current::size::value)+1) == (Dimensions::size::value)
 255         >::template apply<Begin, Current, Units, Dimensions, N>::type type;
 256     };
 257 };
 258
 259 template<>
 260 struct make_homogeneous_system_impl<0> {
 261     template<class Begin, class Current, class Units, class Dimensions>
 262     struct apply {
 263         typedef Units type;
 264     };
 265 };
 266
 267 template<class Units>
 268 struct make_homogeneous_system {
 269     typedef typename find_base_dimensions<Units>::type base_dimensions;
 270     typedef homogeneous_system<
 271         typename insertion_sort<
 272             typename make_homogeneous_system_impl<
 273                 Units::size::value
 274             >::template apply<
 275                 Units,
 276                 dimensionless_type,
 277                 dimensionless_type,
 278                 base_dimensions
 279             >::type
 280         >::type
 281     > type;
 282 };
 283
 284 template<int N>
 285 struct extract_base_units {
 286     template<class Begin, class T>
 287     struct apply {
 288         typedef list<
 289             typename Begin::item::tag_type,
 290             typename extract_base_units<N-1>::template apply<typename Begin::next, T>::type
 291         > type;
 292     };
 293 };
 294
 295 template<>
 296 struct extract_base_units<0> {
 297     template<class Begin, class T>
 298     struct apply {
 299         typedef T type;
 300     };
 301 };
 302
 303 }
 304
 305 }
 306
 307 }
 308
 309 #endif