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Telegram/ThirdParty/range-v3/include/range/v3/numeric/adjacent_difference.hpp

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+/// \file
+// Range v3 library
+//
+// Copyright Eric Niebler 2004
+// Copyright Gonzalo Brito Gadeschi 2014
+//
+//  Use, modification and distribution is subject to the
+//  Boost Software License, Version 1.0. (See accompanying
+//  file LICENSE_1_0.txt or copy at
+//  http://www.boost.org/LICENSE_1_0.txt)
+//
+// Project home: https://github.com/ericniebler/range-v3
+//
+// Implementation based on the code in libc++
+//   http://http://libcxx.llvm.org/
+
+#ifndef RANGES_V3_NUMERIC_ADJACENT_DIFFERENCE_HPP
+#define RANGES_V3_NUMERIC_ADJACENT_DIFFERENCE_HPP
+
+#include <meta/meta.hpp>
+
+#include <range/v3/algorithm/result_types.hpp>
+#include <range/v3/functional/arithmetic.hpp>
+#include <range/v3/functional/identity.hpp>
+#include <range/v3/functional/invoke.hpp>
+#include <range/v3/iterator/concepts.hpp>
+#include <range/v3/iterator/traits.hpp>
+#include <range/v3/iterator/unreachable_sentinel.hpp>
+#include <range/v3/range/access.hpp>
+#include <range/v3/range/concepts.hpp>
+#include <range/v3/range/dangling.hpp>
+#include <range/v3/range/traits.hpp>
+#include <range/v3/utility/static_const.hpp>
+
+#include <range/v3/detail/prologue.hpp>
+
+namespace ranges
+{
+    /// \addtogroup group-numerics
+    /// @{
+    // clang-format off
+    /// \concept differenceable_
+    /// \brief The \c differenceable_ concept
+    template(typename I, typename O, typename BOp, typename P)(
+    concept (differenceable_)(I, O, BOp, P),
+        invocable<P&, iter_value_t<I>> AND
+        copy_constructible<uncvref_t<invoke_result_t<P&, iter_value_t<I>>>> AND
+        movable<uncvref_t<invoke_result_t<P&, iter_value_t<I>>>> AND
+        output_iterator<O, invoke_result_t<P&, iter_value_t<I>>> AND
+        invocable<
+            BOp&,
+            invoke_result_t<
+                P&,
+                iter_value_t<I>>,
+                invoke_result_t<P&, iter_value_t<I>>> AND
+        output_iterator<
+            O,
+            invoke_result_t<
+                BOp&,
+                invoke_result_t<P&, iter_value_t<I>>,
+                invoke_result_t<P&, iter_value_t<I>>>>);
+
+    /// \concept differenceable
+    /// \brief The \c differenceable concept
+    template<typename I, typename O, typename BOp = minus, typename P = identity>
+    CPP_concept differenceable =
+        input_iterator<I> &&
+        CPP_concept_ref(ranges::differenceable_, I, O, BOp, P);
+    // clang-format on
+
+    template<typename I, typename O>
+    using adjacent_difference_result = detail::in_out_result<I, O>;
+
+    struct adjacent_difference_fn
+    {
+        template(typename I, typename S, typename O, typename S2, typename BOp = minus,
+                 typename P = identity)(
+            requires sentinel_for<S, I> AND sentinel_for<S2, O> AND
+                differenceable<I, O, BOp, P>)
+        adjacent_difference_result<I, O> operator()(I first,
+                                                    S last,
+                                                    O result,
+                                                    S2 end_result,
+                                                    BOp bop = BOp{},
+                                                    P proj = P{}) const
+        {
+            // BUGBUG think about the use of coerce here.
+            using V = iter_value_t<I>;
+            using X = invoke_result_t<P &, V>;
+            coerce<V> v;
+            coerce<X> x;
+
+            if(first != last && result != end_result)
+            {
+                auto t1(x(invoke(proj, v(*first))));
+                *result = t1;
+                for(++first, ++result; first != last && result != end_result;
+                    ++first, ++result)
+                {
+                    auto t2(x(invoke(proj, v(*first))));
+                    *result = invoke(bop, t2, t1);
+                    t1 = std::move(t2);
+                }
+            }
+            return {first, result};
+        }
+
+        template(typename I, typename S, typename O, typename BOp = minus,
+                 typename P = identity)(
+            requires sentinel_for<S, I> AND differenceable<I, O, BOp, P>)
+        adjacent_difference_result<I, O> //
+        operator()(I first, S last, O result, BOp bop = BOp{}, P proj = P{}) const
+        {
+            return (*this)(std::move(first),
+                           std::move(last),
+                           std::move(result),
+                           unreachable,
+                           std::move(bop),
+                           std::move(proj));
+        }
+
+        template(typename Rng, typename ORef, typename BOp = minus, typename P = identity,
+                 typename I = iterator_t<Rng>, typename O = uncvref_t<ORef>)(
+            requires range<Rng> AND differenceable<I, O, BOp, P>)
+        adjacent_difference_result<borrowed_iterator_t<Rng>, O> //
+        operator()(Rng && rng, ORef && result, BOp bop = BOp{}, P proj = P{}) const
+        {
+            return (*this)(begin(rng),
+                           end(rng),
+                           static_cast<ORef &&>(result),
+                           std::move(bop),
+                           std::move(proj));
+        }
+
+        template(typename Rng, typename ORng, typename BOp = minus, typename P = identity,
+                 typename I = iterator_t<Rng>, typename O = iterator_t<ORng>)(
+            requires range<Rng> AND range<ORng> AND differenceable<I, O, BOp, P>)
+        adjacent_difference_result<borrowed_iterator_t<Rng>, borrowed_iterator_t<ORng>>
+        operator()(Rng && rng, ORng && result, BOp bop = BOp{}, P proj = P{}) const
+        {
+            return (*this)(begin(rng),
+                           end(rng),
+                           begin(result),
+                           end(result),
+                           std::move(bop),
+                           std::move(proj));
+        }
+    };
+
+    RANGES_INLINE_VARIABLE(adjacent_difference_fn, adjacent_difference)
+    /// @}
+} // namespace ranges
+
+#include <range/v3/detail/epilogue.hpp>
+
+#endif