59 lines
1.7 KiB
C++
59 lines
1.7 KiB
C++
/// \file
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// Range v3 library
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//
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// Copyright Eric Niebler 2014
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//
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// Use, modification and distribution is subject to the
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// Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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//
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// Project home: https://github.com/ericniebler/range-v3
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//
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#ifndef RANGES_V3_ALGORITHM_GENERATE_N_HPP
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#define RANGES_V3_ALGORITHM_GENERATE_N_HPP
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#include <tuple>
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#include <utility>
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#include <range/v3/range_fwd.hpp>
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#include <range/v3/begin_end.hpp>
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#include <range/v3/range_concepts.hpp>
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#include <range/v3/range_traits.hpp>
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#include <range/v3/utility/iterator.hpp>
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#include <range/v3/utility/iterator_concepts.hpp>
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#include <range/v3/utility/static_const.hpp>
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#include <range/v3/utility/tagged_pair.hpp>
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#include <range/v3/algorithm/tagspec.hpp>
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namespace ranges
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{
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inline namespace v3
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{
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/// \addtogroup group-algorithms
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/// @{
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struct generate_n_fn
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{
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template<typename O, typename F,
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CONCEPT_REQUIRES_(Invocable<F&>() &&
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OutputIterator<O, result_of_t<F&()>>())>
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tagged_pair<tag::out(O), tag::fun(F)>
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operator()(O begin, difference_type_t<O> n, F fun) const
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{
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RANGES_EXPECT(n >= 0);
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auto norig = n;
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auto b = uncounted(begin);
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for(; 0 != n; ++b, --n)
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*b = invoke(fun);
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return {recounted(begin, b, norig), detail::move(fun)};
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}
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};
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/// \sa `generate_n_fn`
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/// \ingroup group-algorithms
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RANGES_INLINE_VARIABLE(generate_n_fn, generate_n)
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// @}
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} // namespace v3
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} // namespace ranges
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#endif // include guard
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