v3/algorithm/find.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_HPP
0014 #define RANGES_V3_ALGORITHM_FIND_HPP
0015
0016 #include <utility>
0017
0018 #include <range/v3/range_fwd.hpp>
0019
0020 #include <range/v3/functional/identity.hpp>
0021 #include <range/v3/functional/invoke.hpp>
0022 #include <range/v3/iterator/concepts.hpp>
0023 #include <range/v3/iterator/traits.hpp>
0024 #include <range/v3/range/access.hpp>
0025 #include <range/v3/range/concepts.hpp>
0026 #include <range/v3/range/dangling.hpp>
0027 #include <range/v3/range/traits.hpp>
0028 #include <range/v3/utility/static_const.hpp>
0029
0030 #include <range/v3/detail/prologue.hpp>
0031
0032 namespace ranges
0033 {
0034     /// \addtogroup group-algorithms
0035     /// @{
0036     RANGES_FUNC_BEGIN(find)
0037         /// \brief template function \c find
0038         ///
0039         /// range-based version of the \c find std algorithm
0040         ///
0041         /// \pre `Rng` is a model of the `range` concept
0042         /// \pre `I` is a model of the `input_iterator` concept
0043         /// \pre `S` is a model of the `sentinel_for<I>` concept
0044         /// \pre `P` is a model of the `invocable<iter_common_reference_t<I>>` concept
0045         /// \pre The ResultType of `P` is equality_comparable with V
0046         template(typename I, typename S, typename V, typename P = identity)(
0047             requires input_iterator<I> AND sentinel_for<S, I> AND
0048             indirect_relation<equal_to, projected<I, P>, V const *>)
0049         constexpr I RANGES_FUNC(find)(I first, S last, V const & val, P proj = P{})
0050         {
0051             for(; first != last; ++first)
0052                 if(invoke(proj, *first) == val)
0053                     break;
0054             return first;
0055         }
0056
0057         /// \overload
0058         template(typename Rng, typename V, typename P = identity)(
0059             requires input_range<Rng> AND
0060             indirect_relation<equal_to, projected<iterator_t<Rng>, P>, V const *>)
0061         constexpr borrowed_iterator_t<Rng> //
0062         RANGES_FUNC(find)(Rng && rng, V const & val, P proj = P{})
0063         {
0064             return (*this)(begin(rng), end(rng), val, std::move(proj));
0065         }
0066
0067     RANGES_FUNC_END(find)
0068
0069     namespace cpp20
0070     {
0071         using ranges::find;
0072     }
0073     /// @}
0074 } // namespace ranges
0075
0076 #include <range/v3/detail/epilogue.hpp>
0077
0078 #endif