mp_with_index.hpp 16 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/mp11/detail/config.hpp>
  11. #include <type_traits>
  12. #include <utility>
  13. #include <cassert>
  14. #if defined( BOOST_MP11_HAS_CXX14_CONSTEXPR )
  15. # define BOOST_MP11_CONSTEXPR14 constexpr
  16. #else
  17. # define BOOST_MP11_CONSTEXPR14
  18. #endif
  19. #if defined( _MSC_VER ) && !defined( __clang__ )
  20. # define BOOST_MP11_UNREACHABLE() __assume(false)
  21. #else
  22. # define BOOST_MP11_UNREACHABLE() __builtin_unreachable()
  23. #endif
  24. namespace boost
  25. {
  26. namespace mp11
  27. {
  28. namespace detail
  29. {
  30. template<std::size_t N> struct mp_with_index_impl_
  31. {
  32. 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 )
  33. {
  34. switch( i )
  35. {
  36. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  37. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  38. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  39. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  40. case 4: return std::forward<F>(f)( mp_size_t<K+4>() );
  41. case 5: return std::forward<F>(f)( mp_size_t<K+5>() );
  42. case 6: return std::forward<F>(f)( mp_size_t<K+6>() );
  43. case 7: return std::forward<F>(f)( mp_size_t<K+7>() );
  44. case 8: return std::forward<F>(f)( mp_size_t<K+8>() );
  45. case 9: return std::forward<F>(f)( mp_size_t<K+9>() );
  46. case 10: return std::forward<F>(f)( mp_size_t<K+10>() );
  47. case 11: return std::forward<F>(f)( mp_size_t<K+11>() );
  48. case 12: return std::forward<F>(f)( mp_size_t<K+12>() );
  49. case 13: return std::forward<F>(f)( mp_size_t<K+13>() );
  50. case 14: return std::forward<F>(f)( mp_size_t<K+14>() );
  51. case 15: return std::forward<F>(f)( mp_size_t<K+15>() );
  52. }
  53. return mp_with_index_impl_<N-16>::template call<K+16>( i-16, std::forward<F>(f) );
  54. }
  55. };
  56. template<> struct mp_with_index_impl_<0>
  57. {
  58. };
  59. template<> struct mp_with_index_impl_<1>
  60. {
  61. 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 )
  62. {
  63. return std::forward<F>(f)( mp_size_t<K+0>() );
  64. }
  65. };
  66. template<> struct mp_with_index_impl_<2>
  67. {
  68. 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 )
  69. {
  70. switch( i )
  71. {
  72. default: BOOST_MP11_UNREACHABLE();
  73. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  74. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  75. }
  76. }
  77. };
  78. template<> struct mp_with_index_impl_<3>
  79. {
  80. 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 )
  81. {
  82. switch( i )
  83. {
  84. default: BOOST_MP11_UNREACHABLE();
  85. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  86. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  87. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  88. }
  89. }
  90. };
  91. template<> struct mp_with_index_impl_<4>
  92. {
  93. 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 )
  94. {
  95. switch( i )
  96. {
  97. default: BOOST_MP11_UNREACHABLE();
  98. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  99. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  100. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  101. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  102. }
  103. }
  104. };
  105. template<> struct mp_with_index_impl_<5>
  106. {
  107. 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 )
  108. {
  109. switch( i )
  110. {
  111. default: BOOST_MP11_UNREACHABLE();
  112. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  113. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  114. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  115. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  116. case 4: return std::forward<F>(f)( mp_size_t<K+4>() );
  117. }
  118. }
  119. };
  120. template<> struct mp_with_index_impl_<6>
  121. {
  122. 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 )
  123. {
  124. switch( i )
  125. {
  126. default: BOOST_MP11_UNREACHABLE();
  127. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  128. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  129. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  130. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  131. case 4: return std::forward<F>(f)( mp_size_t<K+4>() );
  132. case 5: return std::forward<F>(f)( mp_size_t<K+5>() );
  133. }
  134. }
  135. };
  136. template<> struct mp_with_index_impl_<7>
  137. {
  138. 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 )
  139. {
  140. switch( i )
  141. {
  142. default: BOOST_MP11_UNREACHABLE();
  143. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  144. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  145. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  146. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  147. case 4: return std::forward<F>(f)( mp_size_t<K+4>() );
  148. case 5: return std::forward<F>(f)( mp_size_t<K+5>() );
  149. case 6: return std::forward<F>(f)( mp_size_t<K+6>() );
  150. }
  151. }
  152. };
  153. template<> struct mp_with_index_impl_<8>
  154. {
  155. 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 )
  156. {
  157. switch( i )
  158. {
  159. default: BOOST_MP11_UNREACHABLE();
  160. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  161. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  162. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  163. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  164. case 4: return std::forward<F>(f)( mp_size_t<K+4>() );
  165. case 5: return std::forward<F>(f)( mp_size_t<K+5>() );
  166. case 6: return std::forward<F>(f)( mp_size_t<K+6>() );
  167. case 7: return std::forward<F>(f)( mp_size_t<K+7>() );
  168. }
  169. }
  170. };
  171. template<> struct mp_with_index_impl_<9>
  172. {
  173. 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 )
  174. {
  175. switch( i )
  176. {
  177. default: BOOST_MP11_UNREACHABLE();
  178. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  179. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  180. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  181. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  182. case 4: return std::forward<F>(f)( mp_size_t<K+4>() );
  183. case 5: return std::forward<F>(f)( mp_size_t<K+5>() );
  184. case 6: return std::forward<F>(f)( mp_size_t<K+6>() );
  185. case 7: return std::forward<F>(f)( mp_size_t<K+7>() );
  186. case 8: return std::forward<F>(f)( mp_size_t<K+8>() );
  187. }
  188. }
  189. };
  190. template<> struct mp_with_index_impl_<10>
  191. {
  192. 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 )
  193. {
  194. switch( i )
  195. {
  196. default: BOOST_MP11_UNREACHABLE();
  197. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  198. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  199. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  200. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  201. case 4: return std::forward<F>(f)( mp_size_t<K+4>() );
  202. case 5: return std::forward<F>(f)( mp_size_t<K+5>() );
  203. case 6: return std::forward<F>(f)( mp_size_t<K+6>() );
  204. case 7: return std::forward<F>(f)( mp_size_t<K+7>() );
  205. case 8: return std::forward<F>(f)( mp_size_t<K+8>() );
  206. case 9: return std::forward<F>(f)( mp_size_t<K+9>() );
  207. }
  208. }
  209. };
  210. template<> struct mp_with_index_impl_<11>
  211. {
  212. 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 )
  213. {
  214. switch( i )
  215. {
  216. default: BOOST_MP11_UNREACHABLE();
  217. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  218. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  219. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  220. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  221. case 4: return std::forward<F>(f)( mp_size_t<K+4>() );
  222. case 5: return std::forward<F>(f)( mp_size_t<K+5>() );
  223. case 6: return std::forward<F>(f)( mp_size_t<K+6>() );
  224. case 7: return std::forward<F>(f)( mp_size_t<K+7>() );
  225. case 8: return std::forward<F>(f)( mp_size_t<K+8>() );
  226. case 9: return std::forward<F>(f)( mp_size_t<K+9>() );
  227. case 10: return std::forward<F>(f)( mp_size_t<K+10>() );
  228. }
  229. }
  230. };
  231. template<> struct mp_with_index_impl_<12>
  232. {
  233. 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 )
  234. {
  235. switch( i )
  236. {
  237. default: BOOST_MP11_UNREACHABLE();
  238. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  239. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  240. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  241. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  242. case 4: return std::forward<F>(f)( mp_size_t<K+4>() );
  243. case 5: return std::forward<F>(f)( mp_size_t<K+5>() );
  244. case 6: return std::forward<F>(f)( mp_size_t<K+6>() );
  245. case 7: return std::forward<F>(f)( mp_size_t<K+7>() );
  246. case 8: return std::forward<F>(f)( mp_size_t<K+8>() );
  247. case 9: return std::forward<F>(f)( mp_size_t<K+9>() );
  248. case 10: return std::forward<F>(f)( mp_size_t<K+10>() );
  249. case 11: return std::forward<F>(f)( mp_size_t<K+11>() );
  250. }
  251. }
  252. };
  253. template<> struct mp_with_index_impl_<13>
  254. {
  255. 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 )
  256. {
  257. switch( i )
  258. {
  259. default: BOOST_MP11_UNREACHABLE();
  260. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  261. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  262. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  263. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  264. case 4: return std::forward<F>(f)( mp_size_t<K+4>() );
  265. case 5: return std::forward<F>(f)( mp_size_t<K+5>() );
  266. case 6: return std::forward<F>(f)( mp_size_t<K+6>() );
  267. case 7: return std::forward<F>(f)( mp_size_t<K+7>() );
  268. case 8: return std::forward<F>(f)( mp_size_t<K+8>() );
  269. case 9: return std::forward<F>(f)( mp_size_t<K+9>() );
  270. case 10: return std::forward<F>(f)( mp_size_t<K+10>() );
  271. case 11: return std::forward<F>(f)( mp_size_t<K+11>() );
  272. case 12: return std::forward<F>(f)( mp_size_t<K+12>() );
  273. }
  274. }
  275. };
  276. template<> struct mp_with_index_impl_<14>
  277. {
  278. 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 )
  279. {
  280. switch( i )
  281. {
  282. default: BOOST_MP11_UNREACHABLE();
  283. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  284. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  285. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  286. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  287. case 4: return std::forward<F>(f)( mp_size_t<K+4>() );
  288. case 5: return std::forward<F>(f)( mp_size_t<K+5>() );
  289. case 6: return std::forward<F>(f)( mp_size_t<K+6>() );
  290. case 7: return std::forward<F>(f)( mp_size_t<K+7>() );
  291. case 8: return std::forward<F>(f)( mp_size_t<K+8>() );
  292. case 9: return std::forward<F>(f)( mp_size_t<K+9>() );
  293. case 10: return std::forward<F>(f)( mp_size_t<K+10>() );
  294. case 11: return std::forward<F>(f)( mp_size_t<K+11>() );
  295. case 12: return std::forward<F>(f)( mp_size_t<K+12>() );
  296. case 13: return std::forward<F>(f)( mp_size_t<K+13>() );
  297. }
  298. }
  299. };
  300. template<> struct mp_with_index_impl_<15>
  301. {
  302. 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 )
  303. {
  304. switch( i )
  305. {
  306. default: BOOST_MP11_UNREACHABLE();
  307. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  308. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  309. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  310. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  311. case 4: return std::forward<F>(f)( mp_size_t<K+4>() );
  312. case 5: return std::forward<F>(f)( mp_size_t<K+5>() );
  313. case 6: return std::forward<F>(f)( mp_size_t<K+6>() );
  314. case 7: return std::forward<F>(f)( mp_size_t<K+7>() );
  315. case 8: return std::forward<F>(f)( mp_size_t<K+8>() );
  316. case 9: return std::forward<F>(f)( mp_size_t<K+9>() );
  317. case 10: return std::forward<F>(f)( mp_size_t<K+10>() );
  318. case 11: return std::forward<F>(f)( mp_size_t<K+11>() );
  319. case 12: return std::forward<F>(f)( mp_size_t<K+12>() );
  320. case 13: return std::forward<F>(f)( mp_size_t<K+13>() );
  321. case 14: return std::forward<F>(f)( mp_size_t<K+14>() );
  322. }
  323. }
  324. };
  325. template<> struct mp_with_index_impl_<16>
  326. {
  327. 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 )
  328. {
  329. switch( i )
  330. {
  331. default: BOOST_MP11_UNREACHABLE();
  332. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  333. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  334. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  335. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  336. case 4: return std::forward<F>(f)( mp_size_t<K+4>() );
  337. case 5: return std::forward<F>(f)( mp_size_t<K+5>() );
  338. case 6: return std::forward<F>(f)( mp_size_t<K+6>() );
  339. case 7: return std::forward<F>(f)( mp_size_t<K+7>() );
  340. case 8: return std::forward<F>(f)( mp_size_t<K+8>() );
  341. case 9: return std::forward<F>(f)( mp_size_t<K+9>() );
  342. case 10: return std::forward<F>(f)( mp_size_t<K+10>() );
  343. case 11: return std::forward<F>(f)( mp_size_t<K+11>() );
  344. case 12: return std::forward<F>(f)( mp_size_t<K+12>() );
  345. case 13: return std::forward<F>(f)( mp_size_t<K+13>() );
  346. case 14: return std::forward<F>(f)( mp_size_t<K+14>() );
  347. case 15: return std::forward<F>(f)( mp_size_t<K+15>() );
  348. }
  349. }
  350. };
  351. } // namespace detail
  352. 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 )
  353. {
  354. assert( i < N );
  355. return detail::mp_with_index_impl_<N>::template call<0>( i, std::forward<F>(f) );
  356. }
  357. 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 )
  358. {
  359. return mp_with_index<std::size_t{N::value}>( i, std::forward<F>(f) );
  360. }
  361. #undef BOOST_MP11_CONSTEXPR14
  362. #undef BOOST_MP11_UNREACHABLE
  363. } // namespace mp11
  364. } // namespace boost
  365. #endif // #ifndef BOOST_MP11_DETAIL_MP_WITH_INDEX_HPP_INCLUDED