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( __GNUC__ ) || defined( __clang__ )
  20. # define BOOST_MP11_UNREACHABLE_DEFAULT default: __builtin_unreachable();
  21. #elif defined( _MSC_VER )
  22. # define BOOST_MP11_UNREACHABLE_DEFAULT default: __assume(false);
  23. #else
  24. # define BOOST_MP11_UNREACHABLE_DEFAULT
  25. #endif
  26. namespace boost
  27. {
  28. namespace mp11
  29. {
  30. namespace detail
  31. {
  32. template<std::size_t N> struct mp_with_index_impl_
  33. {
  34. 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 )
  35. {
  36. switch( i )
  37. {
  38. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  39. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  40. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  41. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  42. case 4: return std::forward<F>(f)( mp_size_t<K+4>() );
  43. case 5: return std::forward<F>(f)( mp_size_t<K+5>() );
  44. case 6: return std::forward<F>(f)( mp_size_t<K+6>() );
  45. case 7: return std::forward<F>(f)( mp_size_t<K+7>() );
  46. case 8: return std::forward<F>(f)( mp_size_t<K+8>() );
  47. case 9: return std::forward<F>(f)( mp_size_t<K+9>() );
  48. case 10: return std::forward<F>(f)( mp_size_t<K+10>() );
  49. case 11: return std::forward<F>(f)( mp_size_t<K+11>() );
  50. case 12: return std::forward<F>(f)( mp_size_t<K+12>() );
  51. case 13: return std::forward<F>(f)( mp_size_t<K+13>() );
  52. case 14: return std::forward<F>(f)( mp_size_t<K+14>() );
  53. case 15: return std::forward<F>(f)( mp_size_t<K+15>() );
  54. }
  55. return mp_with_index_impl_<N-16>::template call<K+16>( i-16, std::forward<F>(f) );
  56. }
  57. };
  58. template<> struct mp_with_index_impl_<0>
  59. {
  60. };
  61. template<> struct mp_with_index_impl_<1>
  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. return std::forward<F>(f)( mp_size_t<K+0>() );
  66. }
  67. };
  68. template<> struct mp_with_index_impl_<2>
  69. {
  70. 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 )
  71. {
  72. switch( i )
  73. {
  74. BOOST_MP11_UNREACHABLE_DEFAULT
  75. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  76. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  77. }
  78. }
  79. };
  80. template<> struct mp_with_index_impl_<3>
  81. {
  82. 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 )
  83. {
  84. switch( i )
  85. {
  86. BOOST_MP11_UNREACHABLE_DEFAULT
  87. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  88. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  89. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  90. }
  91. }
  92. };
  93. template<> struct mp_with_index_impl_<4>
  94. {
  95. 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 )
  96. {
  97. switch( i )
  98. {
  99. BOOST_MP11_UNREACHABLE_DEFAULT
  100. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  101. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  102. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  103. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  104. }
  105. }
  106. };
  107. template<> struct mp_with_index_impl_<5>
  108. {
  109. 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 )
  110. {
  111. switch( i )
  112. {
  113. BOOST_MP11_UNREACHABLE_DEFAULT
  114. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  115. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  116. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  117. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  118. case 4: return std::forward<F>(f)( mp_size_t<K+4>() );
  119. }
  120. }
  121. };
  122. template<> struct mp_with_index_impl_<6>
  123. {
  124. 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 )
  125. {
  126. switch( i )
  127. {
  128. BOOST_MP11_UNREACHABLE_DEFAULT
  129. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  130. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  131. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  132. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  133. case 4: return std::forward<F>(f)( mp_size_t<K+4>() );
  134. case 5: return std::forward<F>(f)( mp_size_t<K+5>() );
  135. }
  136. }
  137. };
  138. template<> struct mp_with_index_impl_<7>
  139. {
  140. 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 )
  141. {
  142. switch( i )
  143. {
  144. BOOST_MP11_UNREACHABLE_DEFAULT
  145. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  146. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  147. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  148. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  149. case 4: return std::forward<F>(f)( mp_size_t<K+4>() );
  150. case 5: return std::forward<F>(f)( mp_size_t<K+5>() );
  151. case 6: return std::forward<F>(f)( mp_size_t<K+6>() );
  152. }
  153. }
  154. };
  155. template<> struct mp_with_index_impl_<8>
  156. {
  157. 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 )
  158. {
  159. switch( i )
  160. {
  161. BOOST_MP11_UNREACHABLE_DEFAULT
  162. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  163. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  164. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  165. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  166. case 4: return std::forward<F>(f)( mp_size_t<K+4>() );
  167. case 5: return std::forward<F>(f)( mp_size_t<K+5>() );
  168. case 6: return std::forward<F>(f)( mp_size_t<K+6>() );
  169. case 7: return std::forward<F>(f)( mp_size_t<K+7>() );
  170. }
  171. }
  172. };
  173. template<> struct mp_with_index_impl_<9>
  174. {
  175. 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 )
  176. {
  177. switch( i )
  178. {
  179. BOOST_MP11_UNREACHABLE_DEFAULT
  180. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  181. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  182. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  183. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  184. case 4: return std::forward<F>(f)( mp_size_t<K+4>() );
  185. case 5: return std::forward<F>(f)( mp_size_t<K+5>() );
  186. case 6: return std::forward<F>(f)( mp_size_t<K+6>() );
  187. case 7: return std::forward<F>(f)( mp_size_t<K+7>() );
  188. case 8: return std::forward<F>(f)( mp_size_t<K+8>() );
  189. }
  190. }
  191. };
  192. template<> struct mp_with_index_impl_<10>
  193. {
  194. 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 )
  195. {
  196. switch( i )
  197. {
  198. BOOST_MP11_UNREACHABLE_DEFAULT
  199. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  200. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  201. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  202. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  203. case 4: return std::forward<F>(f)( mp_size_t<K+4>() );
  204. case 5: return std::forward<F>(f)( mp_size_t<K+5>() );
  205. case 6: return std::forward<F>(f)( mp_size_t<K+6>() );
  206. case 7: return std::forward<F>(f)( mp_size_t<K+7>() );
  207. case 8: return std::forward<F>(f)( mp_size_t<K+8>() );
  208. case 9: return std::forward<F>(f)( mp_size_t<K+9>() );
  209. }
  210. }
  211. };
  212. template<> struct mp_with_index_impl_<11>
  213. {
  214. 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 )
  215. {
  216. switch( i )
  217. {
  218. BOOST_MP11_UNREACHABLE_DEFAULT
  219. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  220. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  221. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  222. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  223. case 4: return std::forward<F>(f)( mp_size_t<K+4>() );
  224. case 5: return std::forward<F>(f)( mp_size_t<K+5>() );
  225. case 6: return std::forward<F>(f)( mp_size_t<K+6>() );
  226. case 7: return std::forward<F>(f)( mp_size_t<K+7>() );
  227. case 8: return std::forward<F>(f)( mp_size_t<K+8>() );
  228. case 9: return std::forward<F>(f)( mp_size_t<K+9>() );
  229. case 10: return std::forward<F>(f)( mp_size_t<K+10>() );
  230. }
  231. }
  232. };
  233. template<> struct mp_with_index_impl_<12>
  234. {
  235. 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 )
  236. {
  237. switch( i )
  238. {
  239. BOOST_MP11_UNREACHABLE_DEFAULT
  240. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  241. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  242. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  243. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  244. case 4: return std::forward<F>(f)( mp_size_t<K+4>() );
  245. case 5: return std::forward<F>(f)( mp_size_t<K+5>() );
  246. case 6: return std::forward<F>(f)( mp_size_t<K+6>() );
  247. case 7: return std::forward<F>(f)( mp_size_t<K+7>() );
  248. case 8: return std::forward<F>(f)( mp_size_t<K+8>() );
  249. case 9: return std::forward<F>(f)( mp_size_t<K+9>() );
  250. case 10: return std::forward<F>(f)( mp_size_t<K+10>() );
  251. case 11: return std::forward<F>(f)( mp_size_t<K+11>() );
  252. }
  253. }
  254. };
  255. template<> struct mp_with_index_impl_<13>
  256. {
  257. 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 )
  258. {
  259. switch( i )
  260. {
  261. BOOST_MP11_UNREACHABLE_DEFAULT
  262. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  263. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  264. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  265. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  266. case 4: return std::forward<F>(f)( mp_size_t<K+4>() );
  267. case 5: return std::forward<F>(f)( mp_size_t<K+5>() );
  268. case 6: return std::forward<F>(f)( mp_size_t<K+6>() );
  269. case 7: return std::forward<F>(f)( mp_size_t<K+7>() );
  270. case 8: return std::forward<F>(f)( mp_size_t<K+8>() );
  271. case 9: return std::forward<F>(f)( mp_size_t<K+9>() );
  272. case 10: return std::forward<F>(f)( mp_size_t<K+10>() );
  273. case 11: return std::forward<F>(f)( mp_size_t<K+11>() );
  274. case 12: return std::forward<F>(f)( mp_size_t<K+12>() );
  275. }
  276. }
  277. };
  278. template<> struct mp_with_index_impl_<14>
  279. {
  280. 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 )
  281. {
  282. switch( i )
  283. {
  284. BOOST_MP11_UNREACHABLE_DEFAULT
  285. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  286. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  287. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  288. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  289. case 4: return std::forward<F>(f)( mp_size_t<K+4>() );
  290. case 5: return std::forward<F>(f)( mp_size_t<K+5>() );
  291. case 6: return std::forward<F>(f)( mp_size_t<K+6>() );
  292. case 7: return std::forward<F>(f)( mp_size_t<K+7>() );
  293. case 8: return std::forward<F>(f)( mp_size_t<K+8>() );
  294. case 9: return std::forward<F>(f)( mp_size_t<K+9>() );
  295. case 10: return std::forward<F>(f)( mp_size_t<K+10>() );
  296. case 11: return std::forward<F>(f)( mp_size_t<K+11>() );
  297. case 12: return std::forward<F>(f)( mp_size_t<K+12>() );
  298. case 13: return std::forward<F>(f)( mp_size_t<K+13>() );
  299. }
  300. }
  301. };
  302. template<> struct mp_with_index_impl_<15>
  303. {
  304. 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 )
  305. {
  306. switch( i )
  307. {
  308. BOOST_MP11_UNREACHABLE_DEFAULT
  309. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  310. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  311. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  312. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  313. case 4: return std::forward<F>(f)( mp_size_t<K+4>() );
  314. case 5: return std::forward<F>(f)( mp_size_t<K+5>() );
  315. case 6: return std::forward<F>(f)( mp_size_t<K+6>() );
  316. case 7: return std::forward<F>(f)( mp_size_t<K+7>() );
  317. case 8: return std::forward<F>(f)( mp_size_t<K+8>() );
  318. case 9: return std::forward<F>(f)( mp_size_t<K+9>() );
  319. case 10: return std::forward<F>(f)( mp_size_t<K+10>() );
  320. case 11: return std::forward<F>(f)( mp_size_t<K+11>() );
  321. case 12: return std::forward<F>(f)( mp_size_t<K+12>() );
  322. case 13: return std::forward<F>(f)( mp_size_t<K+13>() );
  323. case 14: return std::forward<F>(f)( mp_size_t<K+14>() );
  324. }
  325. }
  326. };
  327. template<> struct mp_with_index_impl_<16>
  328. {
  329. 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 )
  330. {
  331. switch( i )
  332. {
  333. BOOST_MP11_UNREACHABLE_DEFAULT
  334. case 0: return std::forward<F>(f)( mp_size_t<K+0>() );
  335. case 1: return std::forward<F>(f)( mp_size_t<K+1>() );
  336. case 2: return std::forward<F>(f)( mp_size_t<K+2>() );
  337. case 3: return std::forward<F>(f)( mp_size_t<K+3>() );
  338. case 4: return std::forward<F>(f)( mp_size_t<K+4>() );
  339. case 5: return std::forward<F>(f)( mp_size_t<K+5>() );
  340. case 6: return std::forward<F>(f)( mp_size_t<K+6>() );
  341. case 7: return std::forward<F>(f)( mp_size_t<K+7>() );
  342. case 8: return std::forward<F>(f)( mp_size_t<K+8>() );
  343. case 9: return std::forward<F>(f)( mp_size_t<K+9>() );
  344. case 10: return std::forward<F>(f)( mp_size_t<K+10>() );
  345. case 11: return std::forward<F>(f)( mp_size_t<K+11>() );
  346. case 12: return std::forward<F>(f)( mp_size_t<K+12>() );
  347. case 13: return std::forward<F>(f)( mp_size_t<K+13>() );
  348. case 14: return std::forward<F>(f)( mp_size_t<K+14>() );
  349. case 15: return std::forward<F>(f)( mp_size_t<K+15>() );
  350. }
  351. }
  352. };
  353. } // namespace detail
  354. 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 )
  355. {
  356. assert( i < N );
  357. return detail::mp_with_index_impl_<N>::template call<0>( i, std::forward<F>(f) );
  358. }
  359. 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 )
  360. {
  361. return mp_with_index<std::size_t{N::value}>( i, std::forward<F>(f) );
  362. }
  363. #undef BOOST_MP11_CONSTEXPR14
  364. #undef BOOST_MP11_UNREACHABLE_DEFAULT
  365. } // namespace mp11
  366. } // namespace boost
  367. #endif // #ifndef BOOST_MP11_DETAIL_MP_WITH_INDEX_HPP_INCLUDED