v3/algorithm/find_first_of.hpp

0001 /// \file
0002 // Range v3 library
0003 //
0004 //  Copyright Eric Niebler 2014-present
0005 //
0006 //  Use, modification and distribution is subject to the
0007 //  Boost Software License, Version 1.0. (See accompanying
0008 //  file LICENSE_1_0.txt or copy at
0009 //  http://www.boost.org/LICENSE_1_0.txt)
0010 //
0011 // Project home: https://github.com/ericniebler/range-v3
0012 //
0013 #ifndef RANGES_V3_ALGORITHM_FIND_FIRST_OF_HPP
0014 #define RANGES_V3_ALGORITHM_FIND_FIRST_OF_HPP
0015
0016 #include <utility>
0017
0018 #include <range/v3/range_fwd.hpp>
0019
0020 #include <range/v3/functional/comparisons.hpp>
0021 #include <range/v3/functional/identity.hpp>
0022 #include <range/v3/functional/invoke.hpp>
0023 #include <range/v3/iterator/concepts.hpp>
0024 #include <range/v3/iterator/traits.hpp>
0025 #include <range/v3/range/access.hpp>
0026 #include <range/v3/range/concepts.hpp>
0027 #include <range/v3/range/dangling.hpp>
0028 #include <range/v3/range/traits.hpp>
0029 #include <range/v3/utility/static_const.hpp>
0030
0031 #include <range/v3/detail/prologue.hpp>
0032
0033 namespace ranges
0034 {
0035     /// \addtogroup group-algorithms
0036     /// @{
0037     RANGES_FUNC_BEGIN(find_first_of)
0038         // Rationale: return I0 instead of pair<I0,I1> because find_first_of need
0039         // not actually compute the end of [I1,S0); therefore, it is not necessarily
0040         // losing information. E.g., if begin0 == end0, we can return begin0 immediately.
0041         // If we returned pair<I0,I1>, we would need to do an O(N) scan to find the
0042         // end position.
0043
0044         /// \brief function template \c find_first_of
0045         template(typename I0,
0046                  typename S0,
0047                  typename I1,
0048                  typename S1,
0049                  typename R = equal_to,
0050                  typename P0 = identity,
0051                  typename P1 = identity)(
0052             requires input_iterator<I0> AND sentinel_for<S0, I0> AND
0053                 forward_iterator<I1> AND sentinel_for<S1, I1> AND
0054                 indirect_relation<R, projected<I0, P0>, projected<I1, P1>>)
0055         constexpr I0 RANGES_FUNC(find_first_of)(I0 begin0,
0056                                                 S0 end0,
0057                                                 I1 begin1,
0058                                                 S1 end1,
0059                                                 R pred = R{},
0060                                                 P0 proj0 = P0{},
0061                                                 P1 proj1 = P1{}) //
0062         {
0063             for(; begin0 != end0; ++begin0)
0064                 for(auto tmp = begin1; tmp != end1; ++tmp)
0065                     if(invoke(pred, invoke(proj0, *begin0), invoke(proj1, *tmp)))
0066                         return begin0;
0067             return begin0;
0068         }
0069
0070         /// \overload
0071         template(typename Rng0,
0072                      typename Rng1,
0073                      typename R = equal_to,
0074                      typename P0 = identity,
0075                      typename P1 = identity)(
0076             requires input_range<Rng0> AND forward_range<Rng1> AND
0077                 indirect_relation<R,
0078                                   projected<iterator_t<Rng0>, P0>,
0079                                   projected<iterator_t<Rng1>, P1>>)
0080         constexpr borrowed_iterator_t<Rng0> RANGES_FUNC(find_first_of)(
0081             Rng0 && rng0, Rng1 && rng1, R pred = R{}, P0 proj0 = P0{}, P1 proj1 = P1{}) //
0082         {
0083             return (*this)(begin(rng0),
0084                            end(rng0),
0085                            begin(rng1),
0086                            end(rng1),
0087                            std::move(pred),
0088                            std::move(proj0),
0089                            std::move(proj1));
0090         }
0091
0092     RANGES_FUNC_END(find_first_of)
0093
0094     namespace cpp20
0095     {
0096         using ranges::find_first_of;
0097     }
0098     /// @}
0099 } // namespace ranges
0100
0101 #include <range/v3/detail/epilogue.hpp>
0102
0103 #endif