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 +1,75 @@
+/*!
+@file
+Defines `boost::hana::drop_back`.
+
+@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_DROP_BACK_HPP
+#define BOOST_HANA_DROP_BACK_HPP
+
+#include <boost/hana/fwd/drop_back.hpp>
+
+#include <boost/hana/at.hpp>
+#include <boost/hana/concept/integral_constant.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/integral_constant.hpp>
+#include <boost/hana/length.hpp>
+
+#include <cstddef>
+#include <utility>
+
+
+BOOST_HANA_NAMESPACE_BEGIN
+    //! @cond
+    template <typename Xs, typename N>
+    constexpr auto drop_back_t::operator()(Xs&& xs, N const& n) const {
+        using S = typename hana::tag_of<Xs>::type;
+        using DropBack = BOOST_HANA_DISPATCH_IF(drop_back_impl<S>,
+            hana::Sequence<S>::value &&
+            hana::IntegralConstant<N>::value
+        );
+
+    #ifndef BOOST_HANA_CONFIG_DISABLE_CONCEPT_CHECKS
+        static_assert(hana::Sequence<S>::value,
+        "hana::drop_back(xs, n) requires 'xs' to be a Sequence");
+
+        static_assert(hana::IntegralConstant<N>::value,
+        "hana::drop_back(xs, n) requires 'n' to be an IntegralConstant");
+    #endif
+
+        static_assert(N::value >= 0,
+        "hana::drop_back(xs, n) requires 'n' to be non-negative");
+
+        return DropBack::apply(static_cast<Xs&&>(xs), n);
+    }
+
+    template <typename Xs>
+    constexpr auto drop_back_t::operator()(Xs&& xs) const {
+        return (*this)(static_cast<Xs&&>(xs), hana::size_c<1>);
+    }
+    //! @endcond
+
+    template <typename S, bool condition>
+    struct drop_back_impl<S, when<condition>> : default_ {
+        template <typename Xs, std::size_t ...n>
+        static constexpr auto drop_back_helper(Xs&& xs, std::index_sequence<n...>) {
+            return hana::make<S>(hana::at_c<n>(static_cast<Xs&&>(xs))...);
+        }
+
+        template <typename Xs, typename N>
+        static constexpr auto apply(Xs&& xs, N const&) {
+            constexpr std::size_t n = N::value;
+            constexpr std::size_t len = decltype(hana::length(xs))::value;
+            return drop_back_helper(static_cast<Xs&&>(xs),
+                                    std::make_index_sequence<(n > len ? 0 : len - n)>{});
+        }
+    };
+BOOST_HANA_NAMESPACE_END
+
+#endif // !BOOST_HANA_DROP_BACK_HPP