stabilize build system: depends, installer, boost/bdb fixes, cross targets groundwork

2026-02-24 18:38:47 +00:00
parent da8c28aaeb
commit 65cb2619a7
13106 changed files with 2484322 additions and 1804 deletions
@@ -0,0 +1,99 @@
+/*!
+@file
+Defines `boost::hana::slice` and `boost::hana::slice_c`.
+
+@copyright Louis Dionne 2013-2017
+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_SLICE_HPP
+#define BOOST_HANA_SLICE_HPP
+
+#include <boost/hana/fwd/slice.hpp>
+
+#include <boost/hana/at.hpp>
+#include <boost/hana/concept/foldable.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/range.hpp>
+#include <boost/hana/unpack.hpp>
+
+#include <cstddef>
+#include <utility>
+
+
+BOOST_HANA_NAMESPACE_BEGIN
+    //! @cond
+    template <typename Xs, typename Indices>
+    constexpr auto slice_t::operator()(Xs&& xs, Indices&& indices) const {
+        using S = typename hana::tag_of<Xs>::type;
+        using Slice = BOOST_HANA_DISPATCH_IF(slice_impl<S>,
+            hana::Sequence<S>::value &&
+            hana::Foldable<Indices>::value
+        );
+
+    #ifndef BOOST_HANA_CONFIG_DISABLE_CONCEPT_CHECKS
+        static_assert(hana::Sequence<S>::value,
+        "hana::slice(xs, indices) requires 'xs' to be a Sequence");
+
+        static_assert(hana::Foldable<Indices>::value,
+        "hana::slice(xs, indices) requires 'indices' to be Foldable");
+    #endif
+
+        return Slice::apply(static_cast<Xs&&>(xs), static_cast<Indices&&>(indices));
+    }
+    //! @endcond
+
+    namespace detail {
+        template <typename Xs>
+        struct take_arbitrary {
+            Xs& xs;
+            using S = typename hana::tag_of<Xs>::type;
+
+            template <typename ...N>
+            constexpr auto operator()(N const& ...) const {
+                return hana::make<S>(hana::at_c<N::value>(xs)...);
+            }
+        };
+    }
+
+    template <typename S, bool condition>
+    struct slice_impl<S, when<condition>> : default_ {
+        template <std::size_t from, typename Xs, std::size_t ...i>
+        static constexpr auto from_offset(Xs&& xs, std::index_sequence<i...>) {
+            return hana::make<S>(hana::at_c<from + i>(static_cast<Xs&&>(xs))...);
+        }
+
+        template <typename Xs, typename T, T from, T to>
+        static constexpr auto apply(Xs&& xs, hana::range<T, from, to> const&) {
+            return slice_impl::from_offset<from>(
+                static_cast<Xs&&>(xs), std::make_index_sequence<to - from>{}
+            );
+        }
+
+        //! @todo
+        //! Since we have the right to specify the same index more than once,
+        //! we can't move from the elements of the source sequence even if it
+        //! is a temporary object: we could end up double-moving. Perhaps it
+        //! would be possible to determine the indices from which we can move
+        //! without incurring a too large compile-time penalty?
+        template <typename Xs, typename Indices>
+        static constexpr auto apply(Xs const& xs, Indices const& indices) {
+            return hana::unpack(indices, detail::take_arbitrary<Xs const>{xs});
+        }
+    };
+
+    template <std::size_t from, std::size_t to>
+    struct slice_c_t {
+        template <typename Xs>
+        constexpr auto operator()(Xs&& xs) const {
+            return hana::slice(static_cast<Xs&&>(xs),
+                               hana::range_c<std::size_t, from, to>);
+        }
+    };
+BOOST_HANA_NAMESPACE_END
+
+#endif // !BOOST_HANA_SLICE_HPP