take_while.hpp 1.8 KB

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  1. /// \file
  2. // Range v3 library
  3. //
  4. // Copyright Eric Niebler 2013-present
  5. //
  6. // Use, modification and distribution is subject to the
  7. // Boost Software License, Version 1.0. (See accompanying
  8. // file LICENSE_1_0.txt or copy at
  9. // http://www.boost.org/LICENSE_1_0.txt)
  10. //
  11. // Project home: https://github.com/ericniebler/range-v3
  12. //
  13. #ifndef RANGES_V3_ACTION_TAKE_WHILE_HPP
  14. #define RANGES_V3_ACTION_TAKE_WHILE_HPP
  15. #include <range/v3/range_fwd.hpp>
  16. #include <range/v3/action/action.hpp>
  17. #include <range/v3/action/erase.hpp>
  18. #include <range/v3/algorithm/find_if_not.hpp>
  19. #include <range/v3/functional/bind_back.hpp>
  20. #include <range/v3/iterator/concepts.hpp>
  21. #include <range/v3/iterator/traits.hpp>
  22. #include <range/v3/utility/static_const.hpp>
  23. #include <range/v3/detail/prologue.hpp>
  24. namespace ranges
  25. {
  26. /// \addtogroup group-actions
  27. /// @{
  28. namespace actions
  29. {
  30. struct take_while_fn
  31. {
  32. template(typename Fun)(
  33. requires (!range<Fun>))
  34. constexpr auto operator()(Fun fun) const
  35. {
  36. return make_action_closure(bind_back(take_while_fn{}, std::move(fun)));
  37. }
  38. template(typename Rng, typename Fun)(
  39. requires forward_range<Rng> AND
  40. erasable_range<Rng &, iterator_t<Rng>, sentinel_t<Rng>> AND
  41. indirect_unary_predicate<Fun, iterator_t<Rng>>)
  42. Rng operator()(Rng && rng, Fun fun) const
  43. {
  44. ranges::actions::erase(
  45. rng, find_if_not(begin(rng), end(rng), std::move(fun)), end(rng));
  46. return static_cast<Rng &&>(rng);
  47. }
  48. };
  49. /// \relates actions::take_while_fn
  50. RANGES_INLINE_VARIABLE(take_while_fn, take_while)
  51. } // namespace actions
  52. /// @}
  53. } // namespace ranges
  54. #include <range/v3/detail/epilogue.hpp>
  55. #endif