first_n.hpp 2.6 KB

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  1. # /* Copyright (C) 2001
  2. # * Housemarque Oy
  3. # * http://www.housemarque.com
  4. # *
  5. # * Distributed under the Boost Software License, Version 1.0. (See
  6. # * accompanying file LICENSE_1_0.txt or copy at
  7. # * http://www.boost.org/LICENSE_1_0.txt)
  8. # */
  9. #
  10. # /* Revised by Paul Mensonides (2002) */
  11. #
  12. # /* See http://www.boost.org for most recent version. */
  13. #
  14. # ifndef BOOST_PREPROCESSOR_LIST_FIRST_N_HPP
  15. # define BOOST_PREPROCESSOR_LIST_FIRST_N_HPP
  16. #
  17. # include <boost/preprocessor/arithmetic/dec.hpp>
  18. # include <boost/preprocessor/config/config.hpp>
  19. # include <boost/preprocessor/control/while.hpp>
  20. # include <boost/preprocessor/list/adt.hpp>
  21. # include <boost/preprocessor/list/reverse.hpp>
  22. # include <boost/preprocessor/tuple/elem.hpp>
  23. # include <boost/preprocessor/tuple/rem.hpp>
  24. #
  25. # /* BOOST_PP_LIST_FIRST_N */
  26. #
  27. # if ~BOOST_PP_CONFIG_FLAGS() & BOOST_PP_CONFIG_EDG()
  28. # define BOOST_PP_LIST_FIRST_N(count, list) BOOST_PP_LIST_REVERSE(BOOST_PP_TUPLE_ELEM(3, 2, BOOST_PP_WHILE(BOOST_PP_LIST_FIRST_N_P, BOOST_PP_LIST_FIRST_N_O, (count, list, BOOST_PP_NIL))))
  29. # else
  30. # define BOOST_PP_LIST_FIRST_N(count, list) BOOST_PP_LIST_FIRST_N_I(count, list)
  31. # define BOOST_PP_LIST_FIRST_N_I(count, list) BOOST_PP_LIST_REVERSE(BOOST_PP_TUPLE_ELEM(3, 2, BOOST_PP_WHILE(BOOST_PP_LIST_FIRST_N_P, BOOST_PP_LIST_FIRST_N_O, (count, list, BOOST_PP_NIL))))
  32. # endif
  33. #
  34. # if ~BOOST_PP_CONFIG_FLAGS() & BOOST_PP_CONFIG_EDG()
  35. # define BOOST_PP_LIST_FIRST_N_P(d, data) BOOST_PP_TUPLE_ELEM(3, 0, data)
  36. # else
  37. # define BOOST_PP_LIST_FIRST_N_P(d, data) BOOST_PP_LIST_FIRST_N_P_I data
  38. # define BOOST_PP_LIST_FIRST_N_P_I(c, l, nl) c
  39. # endif
  40. #
  41. # if ~BOOST_PP_CONFIG_FLAGS() & BOOST_PP_CONFIG_MWCC()
  42. # define BOOST_PP_LIST_FIRST_N_O(d, data) BOOST_PP_LIST_FIRST_N_O_D data
  43. # else
  44. # define BOOST_PP_LIST_FIRST_N_O(d, data) BOOST_PP_LIST_FIRST_N_O_D(BOOST_PP_TUPLE_ELEM(3, 0, data), BOOST_PP_TUPLE_ELEM(3, 1, data), BOOST_PP_TUPLE_ELEM(3, 2, data))
  45. # endif
  46. #
  47. # define BOOST_PP_LIST_FIRST_N_O_D(c, l, nl) (BOOST_PP_DEC(c), BOOST_PP_LIST_REST(l), (BOOST_PP_LIST_FIRST(l), nl))
  48. #
  49. # /* BOOST_PP_LIST_FIRST_N_D */
  50. #
  51. # if ~BOOST_PP_CONFIG_FLAGS() & BOOST_PP_CONFIG_EDG()
  52. # define BOOST_PP_LIST_FIRST_N_D(d, count, list) BOOST_PP_LIST_REVERSE_D(d, BOOST_PP_TUPLE_ELEM(3, 2, BOOST_PP_WHILE_ ## d(BOOST_PP_LIST_FIRST_N_P, BOOST_PP_LIST_FIRST_N_O, (count, list, BOOST_PP_NIL))))
  53. # else
  54. # define BOOST_PP_LIST_FIRST_N_D(d, count, list) BOOST_PP_LIST_FIRST_N_D_I(d, count, list)
  55. # define BOOST_PP_LIST_FIRST_N_D_I(d, count, list) BOOST_PP_LIST_REVERSE_D(d, BOOST_PP_TUPLE_ELEM(3, 2, BOOST_PP_WHILE_ ## d(BOOST_PP_LIST_FIRST_N_P, BOOST_PP_LIST_FIRST_N_O, (count, list, BOOST_PP_NIL))))
  56. # endif
  57. #
  58. # endif