68 lines
1.9 KiB
C++
68 lines
1.9 KiB
C++
/// \file
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// Range v3 library
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//
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// Copyright Eric Niebler 2013-present
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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_ACTION_DROP_HPP
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#define RANGES_V3_ACTION_DROP_HPP
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#include <range/v3/range_fwd.hpp>
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#include <range/v3/action/action.hpp>
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#include <range/v3/action/erase.hpp>
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#include <range/v3/functional/bind_back.hpp>
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#include <range/v3/iterator/concepts.hpp>
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#include <range/v3/iterator/operations.hpp>
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#include <range/v3/iterator/traits.hpp>
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#include <range/v3/utility/static_const.hpp>
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#include <range/v3/detail/prologue.hpp>
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namespace ranges
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{
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/// \addtogroup group-actions
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/// @{
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namespace actions
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{
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struct drop_fn
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{
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template(typename Int)(
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/// \pre
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requires detail::integer_like_<Int>)
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constexpr auto operator()(Int n) const
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{
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RANGES_EXPECT(n >= Int(0));
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return make_action_closure(bind_back(drop_fn{}, n));
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}
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template(typename Rng)(
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/// \pre
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requires forward_range<Rng> AND
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erasable_range<Rng &, iterator_t<Rng>, iterator_t<Rng>>)
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Rng operator()(Rng && rng, range_difference_t<Rng> n) const
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{
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RANGES_EXPECT(n >= 0);
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ranges::actions::erase(
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rng, begin(rng), ranges::next(begin(rng), n, end(rng)));
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return static_cast<Rng &&>(rng);
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}
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};
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/// \relates actions::drop_fn
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RANGES_INLINE_VARIABLE(drop_fn, drop)
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} // namespace actions
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/// @}
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} // namespace ranges
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#include <range/v3/detail/epilogue.hpp>
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#endif
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