Added thirdparty: boost library

2026-08-13 02:38:07 +00:00 · 2024-01-06 19:55:56 +02:00
parent bf49f439e1
commit bccd1e7051
15683 changed files with 3239840 additions and 0 deletions
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+/*!
+@file
+Defines `boost::hana::common` and `boost::hana::common_t`.
+
+Copyright Louis Dionne 2013-2022
+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_CORE_COMMON_HPP
+#define BOOST_HANA_CORE_COMMON_HPP
+
+#include <boost/hana/fwd/core/common.hpp>
+
+#include <boost/hana/concept/constant.hpp>
+#include <boost/hana/config.hpp>
+#include <boost/hana/core/when.hpp>
+#include <boost/hana/detail/canonical_constant.hpp>
+#include <boost/hana/detail/std_common_type.hpp>
+#include <boost/hana/detail/void_t.hpp>
+
+#include <type_traits>
+
+
+namespace boost { namespace hana {
+    //////////////////////////////////////////////////////////////////////////
+    // common
+    //////////////////////////////////////////////////////////////////////////
+    //! @cond
+    template <typename T, typename U, typename>
+    struct common : common<T, U, when<true>> { };
+    //! @endcond
+
+    template <typename T, typename U, bool condition>
+    struct common<T, U, when<condition>>
+        : detail::std_common_type<T, U>
+    { };
+
+    template <typename T>
+    struct common<T, T> {
+        using type = T;
+    };
+
+    //////////////////////////////////////////////////////////////////////////
+    // has_common
+    //////////////////////////////////////////////////////////////////////////
+    template <typename T, typename U, typename>
+    struct has_common : std::false_type { };
+
+    template <typename T, typename U>
+    struct has_common<T, U, detail::void_t<typename common<T, U>::type>>
+        : std::true_type
+    { };
+
+    //////////////////////////////////////////////////////////////////////////
+    // Provided common data types for Constants
+    //////////////////////////////////////////////////////////////////////////
+    namespace constant_detail {
+        //! @todo
+        //! This is an awful hack to avoid having
+        //! @code
+        //!     common<integral_constant_tag<int>, integral_constant_tag<long>>
+        //!         ==
+        //!     CanonicalConstant<long>
+        //! @endcode
+        template <typename A, typename B, typename C>
+        struct which {
+            using type = detail::CanonicalConstant<C>;
+        };
+
+        template <template <typename ...> class A, typename T, typename U, typename C>
+        struct which<A<T>, A<U>, C> {
+            using type = A<C>;
+        };
+    }
+
+    template <typename A, typename B>
+    struct common<A, B, when<
+        hana::Constant<A>::value &&
+        hana::Constant<B>::value &&
+        has_common<typename A::value_type, typename B::value_type>::value
+    >> {
+        using type = typename constant_detail::which<
+            A, B,
+            typename common<typename A::value_type,
+                            typename B::value_type>::type
+        >::type;
+    };
+
+    template <typename A, typename B>
+    struct common<A, B, when<
+        hana::Constant<A>::value &&
+        !hana::Constant<B>::value &&
+        has_common<typename A::value_type, B>::value
+    >> {
+        using type = typename common<typename A::value_type, B>::type;
+    };
+
+    template <typename A, typename B>
+    struct common<A, B, when<
+        !hana::Constant<A>::value &&
+        hana::Constant<B>::value &&
+        has_common<A, typename B::value_type>::value
+    >> {
+        using type = typename common<A, typename B::value_type>::type;
+    };
+}} // end namespace boost::hana
+
+#endif // !BOOST_HANA_CORE_COMMON_HPP