mp_with_index.hpp 15 KB

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  1. #ifndef BOOST_MP11_DETAIL_MP_WITH_INDEX_HPP_INCLUDED
  2. #define BOOST_MP11_DETAIL_MP_WITH_INDEX_HPP_INCLUDED
  3. // Copyright 2017 Peter Dimov.
  4. //
  5. // Distributed under the Boost Software License, Version 1.0.
  6. //
  7. // See accompanying file LICENSE_1_0.txt or copy at
  8. // http://www.boost.org/LICENSE_1_0.txt
  9. #include <boost/mp11/integral.hpp>
  10. #include <boost/config.hpp>
  11. #include <type_traits>
  12. #include <utility>
  13. #include <cassert>
  14. #if !defined( BOOST_NO_CXX14_CONSTEXPR )
  15. # define BOOST_MP11_CONSTEXPR14 constexpr
  16. #else
  17. # define BOOST_MP11_CONSTEXPR14
  18. #endif
  19. namespace boost
  20. {
  21. namespace mp11
  22. {
  23. namespace detail
  24. {
  25. template<std::size_t N> struct mp_with_index_impl_
  26. {
  27. template<std::size_t K, class F> static BOOST_MP11_CONSTEXPR14 decltype(std::declval<F>()(std::declval<mp_size_t<0>>())) call( std::size_t i, F && f )
  28. {
  29. switch( i )
  30. {
  31. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  32. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  33. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  34. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  35. case 4: return std::forward<F>(f)( mp_size_t<K+4>() );
  36. case 5: return std::forward<F>(f)( mp_size_t<K+5>() );
  37. case 6: return std::forward<F>(f)( mp_size_t<K+6>() );
  38. case 7: return std::forward<F>(f)( mp_size_t<K+7>() );
  39. case 8: return std::forward<F>(f)( mp_size_t<K+8>() );
  40. case 9: return std::forward<F>(f)( mp_size_t<K+9>() );
  41. case 10: return std::forward<F>(f)( mp_size_t<K+10>() );
  42. case 11: return std::forward<F>(f)( mp_size_t<K+11>() );
  43. case 12: return std::forward<F>(f)( mp_size_t<K+12>() );
  44. case 13: return std::forward<F>(f)( mp_size_t<K+13>() );
  45. case 14: return std::forward<F>(f)( mp_size_t<K+14>() );
  46. case 15: return std::forward<F>(f)( mp_size_t<K+15>() );
  47. }
  48. return mp_with_index_impl_<N-16>::template call<K+16>( i-16, std::forward<F>(f) );
  49. }
  50. };
  51. template<> struct mp_with_index_impl_<0>
  52. {
  53. };
  54. template<> struct mp_with_index_impl_<1>
  55. {
  56. template<std::size_t K, class F> static BOOST_MP11_CONSTEXPR14 decltype(std::declval<F>()(std::declval<mp_size_t<0>>())) call( std::size_t /*i*/, F && f )
  57. {
  58. return std::forward<F>(f)( mp_size_t<K+0>() );
  59. }
  60. };
  61. template<> struct mp_with_index_impl_<2>
  62. {
  63. template<std::size_t K, class F> static BOOST_MP11_CONSTEXPR14 decltype(std::declval<F>()(std::declval<mp_size_t<0>>())) call( std::size_t i, F && f )
  64. {
  65. switch( i )
  66. {
  67. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  68. default: return std::forward<F>(f)( mp_size_t<K+1>() );
  69. }
  70. }
  71. };
  72. template<> struct mp_with_index_impl_<3>
  73. {
  74. template<std::size_t K, class F> static BOOST_MP11_CONSTEXPR14 decltype(std::declval<F>()(std::declval<mp_size_t<0>>())) call( std::size_t i, F && f )
  75. {
  76. switch( i )
  77. {
  78. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  79. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  80. default: return std::forward<F>(f)( mp_size_t<K+2>() );
  81. }
  82. }
  83. };
  84. template<> struct mp_with_index_impl_<4>
  85. {
  86. template<std::size_t K, class F> static BOOST_MP11_CONSTEXPR14 decltype(std::declval<F>()(std::declval<mp_size_t<0>>())) call( std::size_t i, F && f )
  87. {
  88. switch( i )
  89. {
  90. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  91. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  92. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  93. default: return std::forward<F>(f)( mp_size_t<K+3>() );
  94. }
  95. }
  96. };
  97. template<> struct mp_with_index_impl_<5>
  98. {
  99. template<std::size_t K, class F> static BOOST_MP11_CONSTEXPR14 decltype(std::declval<F>()(std::declval<mp_size_t<0>>())) call( std::size_t i, F && f )
  100. {
  101. switch( i )
  102. {
  103. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  104. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  105. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  106. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  107. default: return std::forward<F>(f)( mp_size_t<K+4>() );
  108. }
  109. }
  110. };
  111. template<> struct mp_with_index_impl_<6>
  112. {
  113. template<std::size_t K, class F> static BOOST_MP11_CONSTEXPR14 decltype(std::declval<F>()(std::declval<mp_size_t<0>>())) call( std::size_t i, F && f )
  114. {
  115. switch( i )
  116. {
  117. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  118. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  119. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  120. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  121. case 4: return std::forward<F>(f)( mp_size_t<K+4>() );
  122. default: return std::forward<F>(f)( mp_size_t<K+5>() );
  123. }
  124. }
  125. };
  126. template<> struct mp_with_index_impl_<7>
  127. {
  128. template<std::size_t K, class F> static BOOST_MP11_CONSTEXPR14 decltype(std::declval<F>()(std::declval<mp_size_t<0>>())) call( std::size_t i, F && f )
  129. {
  130. switch( i )
  131. {
  132. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  133. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  134. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  135. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  136. case 4: return std::forward<F>(f)( mp_size_t<K+4>() );
  137. case 5: return std::forward<F>(f)( mp_size_t<K+5>() );
  138. default: return std::forward<F>(f)( mp_size_t<K+6>() );
  139. }
  140. }
  141. };
  142. template<> struct mp_with_index_impl_<8>
  143. {
  144. template<std::size_t K, class F> static BOOST_MP11_CONSTEXPR14 decltype(std::declval<F>()(std::declval<mp_size_t<0>>())) call( std::size_t i, F && f )
  145. {
  146. switch( i )
  147. {
  148. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  149. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  150. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  151. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  152. case 4: return std::forward<F>(f)( mp_size_t<K+4>() );
  153. case 5: return std::forward<F>(f)( mp_size_t<K+5>() );
  154. case 6: return std::forward<F>(f)( mp_size_t<K+6>() );
  155. default: return std::forward<F>(f)( mp_size_t<K+7>() );
  156. }
  157. }
  158. };
  159. template<> struct mp_with_index_impl_<9>
  160. {
  161. template<std::size_t K, class F> static BOOST_MP11_CONSTEXPR14 decltype(std::declval<F>()(std::declval<mp_size_t<0>>())) call( std::size_t i, F && f )
  162. {
  163. switch( i )
  164. {
  165. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  166. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  167. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  168. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  169. case 4: return std::forward<F>(f)( mp_size_t<K+4>() );
  170. case 5: return std::forward<F>(f)( mp_size_t<K+5>() );
  171. case 6: return std::forward<F>(f)( mp_size_t<K+6>() );
  172. case 7: return std::forward<F>(f)( mp_size_t<K+7>() );
  173. default: return std::forward<F>(f)( mp_size_t<K+8>() );
  174. }
  175. }
  176. };
  177. template<> struct mp_with_index_impl_<10>
  178. {
  179. template<std::size_t K, class F> static BOOST_MP11_CONSTEXPR14 decltype(std::declval<F>()(std::declval<mp_size_t<0>>())) call( std::size_t i, F && f )
  180. {
  181. switch( i )
  182. {
  183. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  184. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  185. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  186. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  187. case 4: return std::forward<F>(f)( mp_size_t<K+4>() );
  188. case 5: return std::forward<F>(f)( mp_size_t<K+5>() );
  189. case 6: return std::forward<F>(f)( mp_size_t<K+6>() );
  190. case 7: return std::forward<F>(f)( mp_size_t<K+7>() );
  191. case 8: return std::forward<F>(f)( mp_size_t<K+8>() );
  192. default: return std::forward<F>(f)( mp_size_t<K+9>() );
  193. }
  194. }
  195. };
  196. template<> struct mp_with_index_impl_<11>
  197. {
  198. template<std::size_t K, class F> static BOOST_MP11_CONSTEXPR14 decltype(std::declval<F>()(std::declval<mp_size_t<0>>())) call( std::size_t i, F && f )
  199. {
  200. switch( i )
  201. {
  202. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  203. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  204. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  205. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  206. case 4: return std::forward<F>(f)( mp_size_t<K+4>() );
  207. case 5: return std::forward<F>(f)( mp_size_t<K+5>() );
  208. case 6: return std::forward<F>(f)( mp_size_t<K+6>() );
  209. case 7: return std::forward<F>(f)( mp_size_t<K+7>() );
  210. case 8: return std::forward<F>(f)( mp_size_t<K+8>() );
  211. case 9: return std::forward<F>(f)( mp_size_t<K+9>() );
  212. default: return std::forward<F>(f)( mp_size_t<K+10>() );
  213. }
  214. }
  215. };
  216. template<> struct mp_with_index_impl_<12>
  217. {
  218. template<std::size_t K, class F> static BOOST_MP11_CONSTEXPR14 decltype(std::declval<F>()(std::declval<mp_size_t<0>>())) call( std::size_t i, F && f )
  219. {
  220. switch( i )
  221. {
  222. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  223. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  224. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  225. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  226. case 4: return std::forward<F>(f)( mp_size_t<K+4>() );
  227. case 5: return std::forward<F>(f)( mp_size_t<K+5>() );
  228. case 6: return std::forward<F>(f)( mp_size_t<K+6>() );
  229. case 7: return std::forward<F>(f)( mp_size_t<K+7>() );
  230. case 8: return std::forward<F>(f)( mp_size_t<K+8>() );
  231. case 9: return std::forward<F>(f)( mp_size_t<K+9>() );
  232. case 10: return std::forward<F>(f)( mp_size_t<K+10>() );
  233. default: return std::forward<F>(f)( mp_size_t<K+11>() );
  234. }
  235. }
  236. };
  237. template<> struct mp_with_index_impl_<13>
  238. {
  239. template<std::size_t K, class F> static BOOST_MP11_CONSTEXPR14 decltype(std::declval<F>()(std::declval<mp_size_t<0>>())) call( std::size_t i, F && f )
  240. {
  241. switch( i )
  242. {
  243. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  244. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  245. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  246. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  247. case 4: return std::forward<F>(f)( mp_size_t<K+4>() );
  248. case 5: return std::forward<F>(f)( mp_size_t<K+5>() );
  249. case 6: return std::forward<F>(f)( mp_size_t<K+6>() );
  250. case 7: return std::forward<F>(f)( mp_size_t<K+7>() );
  251. case 8: return std::forward<F>(f)( mp_size_t<K+8>() );
  252. case 9: return std::forward<F>(f)( mp_size_t<K+9>() );
  253. case 10: return std::forward<F>(f)( mp_size_t<K+10>() );
  254. case 11: return std::forward<F>(f)( mp_size_t<K+11>() );
  255. default: return std::forward<F>(f)( mp_size_t<K+12>() );
  256. }
  257. }
  258. };
  259. template<> struct mp_with_index_impl_<14>
  260. {
  261. template<std::size_t K, class F> static BOOST_MP11_CONSTEXPR14 decltype(std::declval<F>()(std::declval<mp_size_t<0>>())) call( std::size_t i, F && f )
  262. {
  263. switch( i )
  264. {
  265. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  266. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  267. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  268. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  269. case 4: return std::forward<F>(f)( mp_size_t<K+4>() );
  270. case 5: return std::forward<F>(f)( mp_size_t<K+5>() );
  271. case 6: return std::forward<F>(f)( mp_size_t<K+6>() );
  272. case 7: return std::forward<F>(f)( mp_size_t<K+7>() );
  273. case 8: return std::forward<F>(f)( mp_size_t<K+8>() );
  274. case 9: return std::forward<F>(f)( mp_size_t<K+9>() );
  275. case 10: return std::forward<F>(f)( mp_size_t<K+10>() );
  276. case 11: return std::forward<F>(f)( mp_size_t<K+11>() );
  277. case 12: return std::forward<F>(f)( mp_size_t<K+12>() );
  278. default: return std::forward<F>(f)( mp_size_t<K+13>() );
  279. }
  280. }
  281. };
  282. template<> struct mp_with_index_impl_<15>
  283. {
  284. template<std::size_t K, class F> static BOOST_MP11_CONSTEXPR14 decltype(std::declval<F>()(std::declval<mp_size_t<0>>())) call( std::size_t i, F && f )
  285. {
  286. switch( i )
  287. {
  288. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  289. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  290. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  291. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  292. case 4: return std::forward<F>(f)( mp_size_t<K+4>() );
  293. case 5: return std::forward<F>(f)( mp_size_t<K+5>() );
  294. case 6: return std::forward<F>(f)( mp_size_t<K+6>() );
  295. case 7: return std::forward<F>(f)( mp_size_t<K+7>() );
  296. case 8: return std::forward<F>(f)( mp_size_t<K+8>() );
  297. case 9: return std::forward<F>(f)( mp_size_t<K+9>() );
  298. case 10: return std::forward<F>(f)( mp_size_t<K+10>() );
  299. case 11: return std::forward<F>(f)( mp_size_t<K+11>() );
  300. case 12: return std::forward<F>(f)( mp_size_t<K+12>() );
  301. case 13: return std::forward<F>(f)( mp_size_t<K+13>() );
  302. default: return std::forward<F>(f)( mp_size_t<K+14>() );
  303. }
  304. }
  305. };
  306. template<> struct mp_with_index_impl_<16>
  307. {
  308. template<std::size_t K, class F> static BOOST_MP11_CONSTEXPR14 decltype(std::declval<F>()(std::declval<mp_size_t<0>>())) call( std::size_t i, F && f )
  309. {
  310. switch( i )
  311. {
  312. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  313. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  314. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  315. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  316. case 4: return std::forward<F>(f)( mp_size_t<K+4>() );
  317. case 5: return std::forward<F>(f)( mp_size_t<K+5>() );
  318. case 6: return std::forward<F>(f)( mp_size_t<K+6>() );
  319. case 7: return std::forward<F>(f)( mp_size_t<K+7>() );
  320. case 8: return std::forward<F>(f)( mp_size_t<K+8>() );
  321. case 9: return std::forward<F>(f)( mp_size_t<K+9>() );
  322. case 10: return std::forward<F>(f)( mp_size_t<K+10>() );
  323. case 11: return std::forward<F>(f)( mp_size_t<K+11>() );
  324. case 12: return std::forward<F>(f)( mp_size_t<K+12>() );
  325. case 13: return std::forward<F>(f)( mp_size_t<K+13>() );
  326. case 14: return std::forward<F>(f)( mp_size_t<K+14>() );
  327. default: return std::forward<F>(f)( mp_size_t<K+15>() );
  328. }
  329. }
  330. };
  331. } // namespace detail
  332. template<std::size_t N, class F> inline BOOST_MP11_CONSTEXPR14 decltype(std::declval<F>()(std::declval<mp_size_t<0>>())) mp_with_index( std::size_t i, F && f )
  333. {
  334. assert( i < N );
  335. return detail::mp_with_index_impl_<N>::template call<0>( i, std::forward<F>(f) );
  336. }
  337. template<class N, class F> inline BOOST_MP11_CONSTEXPR14 decltype(std::declval<F>()(std::declval<mp_size_t<0>>())) mp_with_index( std::size_t i, F && f )
  338. {
  339. return mp_with_index<std::size_t{N::value}>( i, std::forward<F>(f) );
  340. }
  341. #undef BOOST_MP11_CONSTEXPR14
  342. } // namespace mp11
  343. } // namespace boost
  344. #endif // #ifndef BOOST_MP11_DETAIL_MP_WITH_INDEX_HPP_INCLUDED