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Telegram/ThirdParty/range-v3/include/range/v3/view/indices.hpp

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+/// \file
+// Range v3 library
+//
+//  Copyright Eric Niebler 2013-present
+//  Copyright Gonzalo Brito Gadeschi
+//
+//  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
+//
+
+#ifndef RANGES_V3_VIEW_INDICES_HPP
+#define RANGES_V3_VIEW_INDICES_HPP
+
+#include <meta/meta.hpp>
+
+#include <range/v3/range_fwd.hpp>
+
+#include <range/v3/range/concepts.hpp>
+#include <range/v3/utility/static_const.hpp>
+#include <range/v3/view/iota.hpp>
+
+#include <range/v3/detail/prologue.hpp>
+
+namespace ranges
+{
+    namespace views
+    {
+        /// Half-open range of indices: [from, to).
+        struct indices_fn : iota_view<std::size_t>
+        {
+            indices_fn() = default;
+
+            template(typename Val)(
+                requires integral<Val>)
+            iota_view<Val, Val> operator()(Val to) const
+            {
+                return {Val(), to};
+            }
+            template(typename Val)(
+                requires integral<Val>)
+            iota_view<Val, Val> operator()(Val from, Val to) const
+            {
+                return {from, to};
+            }
+        };
+
+        /// Inclusive range of indices: [from, to].
+        struct closed_indices_fn
+        {
+            template(typename Val)(
+                requires integral<Val>)
+            closed_iota_view<Val> operator()(Val to) const
+            {
+                return {Val(), to};
+            }
+            template(typename Val)(
+                requires integral<Val>)
+            closed_iota_view<Val> operator()(Val from, Val to) const
+            {
+                return {from, to};
+            }
+        };
+
+        /// \relates indices_fn
+        /// \ingroup group-views
+        RANGES_INLINE_VARIABLE(indices_fn, indices)
+
+        /// \relates closed_indices_fn
+        /// \ingroup group-views
+        RANGES_INLINE_VARIABLE(closed_indices_fn, closed_indices)
+    } // namespace views
+} // namespace ranges
+
+#include <range/v3/detail/epilogue.hpp>
+
+#endif // RANGES_V3_VIEW_INDICES_HPP