add subtree-ish sources for 12.0.3

[ceph.git] / ceph / src / boost / libs / hana / include / boost / hana / group.hpp

diff --git a/ceph/src/boost/libs/hana/include/boost/hana/group.hpp b/ceph/src/boost/libs/hana/include/boost/hana/group.hpp
new file mode 100644 (file)
index 0000000..66f005a
--- /dev/null
+++ b/ceph/src/boost/libs/hana/include/boost/hana/group.hpp
@@ -0,0 +1,157 @@
+/*!
+@file
+Defines `boost::hana::group`.
+
+@copyright Louis Dionne 2013-2016
+Distributed under the Boost Software License, Version 1.0.
+(See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
+ */
+
+#ifndef BOOST_HANA_GROUP_HPP
+#define BOOST_HANA_GROUP_HPP
+
+#include <boost/hana/fwd/group.hpp>
+
+#include <boost/hana/at.hpp>
+#include <boost/hana/concept/sequence.hpp>
+#include <boost/hana/config.hpp>
+#include <boost/hana/core/dispatch.hpp>
+#include <boost/hana/core/make.hpp>
+#include <boost/hana/detail/algorithm.hpp>
+#include <boost/hana/detail/array.hpp>
+#include <boost/hana/detail/nested_by.hpp> // required by fwd decl
+#include <boost/hana/equal.hpp>
+#include <boost/hana/length.hpp>
+
+#include <cstddef>
+#include <utility>
+
+
+BOOST_HANA_NAMESPACE_BEGIN
+    //! @cond
+    template <typename Xs>
+    constexpr auto group_t::operator()(Xs&& xs) const {
+        using S = typename hana::tag_of<Xs>::type;
+        using Group = BOOST_HANA_DISPATCH_IF(group_impl<S>,
+            hana::Sequence<S>::value
+        );
+
+    #ifndef BOOST_HANA_CONFIG_DISABLE_CONCEPT_CHECKS
+        static_assert(hana::Sequence<S>::value,
+        "hana::group(xs) requires 'xs' to be a Sequence");
+    #endif
+
+        return Group::apply(static_cast<Xs&&>(xs));
+    }
+
+    template <typename Xs, typename Predicate>
+    constexpr auto group_t::operator()(Xs&& xs, Predicate&& pred) const {
+        using S = typename hana::tag_of<Xs>::type;
+        using Group = BOOST_HANA_DISPATCH_IF(group_impl<S>,
+            hana::Sequence<S>::value
+        );
+
+    #ifndef BOOST_HANA_CONFIG_DISABLE_CONCEPT_CHECKS
+        static_assert(hana::Sequence<S>::value,
+        "hana::group(xs, predicate) requires 'xs' to be a Sequence");
+    #endif
+
+        return Group::apply(static_cast<Xs&&>(xs),
+                            static_cast<Predicate&&>(pred));
+    }
+    //! @endcond
+
+    namespace detail {
+        template <typename Xs, std::size_t ...i>
+        constexpr auto get_subsequence_(Xs&& xs, std::index_sequence<i...>) {
+            using S = typename hana::tag_of<Xs>::type;
+            return hana::make<S>(hana::at_c<i>(static_cast<Xs&&>(xs))...);
+        }
+
+        template <std::size_t offset, typename Indices>
+        struct offset_by;
+
+        template <std::size_t offset, std::size_t ...i>
+        struct offset_by<offset, std::index_sequence<i...>> {
+            using type = std::index_sequence<(offset + i)...>;
+        };
+
+        template <bool ...b>
+        struct group_indices {
+            static constexpr bool bs[] = {b...};
+            static constexpr std::size_t n_groups =
+                    detail::count(bs, bs + sizeof(bs), false) + 1;
+
+            static constexpr auto compute_info() {
+                detail::array<std::size_t, n_groups> sizes{}, offsets{};
+                for (std::size_t g = 0, i = 0, offset = 0; g < n_groups; ++g) {
+                    offsets[g] = offset;
+
+                    sizes[g] = 1;
+                    while (i < sizeof...(b) && bs[i++])
+                        ++sizes[g];
+
+                    offset += sizes[g];
+                }
+                return std::make_pair(offsets, sizes);
+            }
+
+            static constexpr auto info = compute_info();
+            static constexpr auto offsets = info.first;
+            static constexpr auto group_sizes = info.second;
+
+            template <typename S, typename Xs, std::size_t ...i>
+            static constexpr auto finish(Xs&& xs, std::index_sequence<i...>) {
+                return hana::make<S>(
+                    detail::get_subsequence_(
+                        static_cast<Xs&&>(xs),
+                        typename offset_by<
+                            offsets[i], std::make_index_sequence<group_sizes[i]>
+                        >::type{}
+                    )...
+                );
+            }
+        };
+    } // end namespace detail
+
+    template <typename S, bool condition>
+    struct group_impl<S, when<condition>> : default_ {
+        template <typename Xs, typename Pred, std::size_t ...i>
+        static constexpr auto
+        group_helper(Xs&& xs, Pred&& pred, std::index_sequence<0, i...>) {
+            using info = detail::group_indices<static_cast<bool>(decltype(
+                pred(hana::at_c<i - 1>(static_cast<Xs&&>(xs)),
+                     hana::at_c<i>(static_cast<Xs&&>(xs)))
+            )::value)...>;
+            return info::template finish<S>(static_cast<Xs&&>(xs),
+                std::make_index_sequence<info::n_groups>{}
+            );
+        }
+
+        template <typename Xs, typename Pred>
+        static constexpr auto
+        group_helper(Xs&& xs, Pred&&, std::index_sequence<0>) {
+            return hana::make<S>(static_cast<Xs&&>(xs));
+        }
+
+        template <typename Xs, typename Pred>
+        static constexpr auto
+        group_helper(Xs&&, Pred&&, std::index_sequence<>) {
+            return hana::make<S>();
+        }
+
+        template <typename Xs, typename Pred>
+        static constexpr auto apply(Xs&& xs, Pred&& pred) {
+            constexpr std::size_t len = decltype(hana::length(xs))::value;
+            return group_helper(static_cast<Xs&&>(xs),
+                                static_cast<Pred&&>(pred),
+                                std::make_index_sequence<len>{});
+        }
+
+        template <typename Xs>
+        static constexpr auto apply(Xs&& xs)
+        { return group_impl::apply(static_cast<Xs&&>(xs), hana::equal); }
+    };
+BOOST_HANA_NAMESPACE_END
+
+#endif // !BOOST_HANA_GROUP_HPP