Added thirdparty: boost library

thirdparty/include/boost/mysql/detail/field_impl.hpp

@@ -0,0 +1,97 @@
+//
+// Copyright (c) 2019-2023 Ruben Perez Hidalgo (rubenperez038 at gmail dot com)
+//
+// Distributed under 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)
+//
+
+#ifndef BOOST_MYSQL_DETAIL_FIELD_IMPL_HPP
+#define BOOST_MYSQL_DETAIL_FIELD_IMPL_HPP
+
+#include <boost/mysql/bad_field_access.hpp>
+#include <boost/mysql/blob.hpp>
+#include <boost/mysql/date.hpp>
+#include <boost/mysql/datetime.hpp>
+#include <boost/mysql/field_kind.hpp>
+#include <boost/mysql/time.hpp>
+
+#include <boost/mp11/algorithm.hpp>
+#include <boost/throw_exception.hpp>
+#include <boost/variant2/variant.hpp>
+
+#include <string>
+#include <type_traits>
+
+namespace boost {
+namespace mysql {
+namespace detail {
+
+// Breaks a circular dependency between field_view and field
+struct field_impl
+{
+    using null_t = boost::variant2::monostate;
+
+    using variant_type = boost::variant2::variant<
+        null_t,         // Any of the below when the value is NULL
+        std::int64_t,   // signed TINYINT, SMALLINT, MEDIUMINT, INT, BIGINT
+        std::uint64_t,  // unsigned TINYINT, SMALLINT, MEDIUMINT, INT, BIGINT, YEAR, BIT
+        std::string,    // CHAR, VARCHAR,  TEXT (all sizes), , ENUM,
+                        // SET, DECIMAL
+        blob,           // BINARY, VARBINARY, BLOB (all sizes), GEOMETRY
+        float,          // FLOAT
+        double,         // DOUBLE
+        date,           // DATE
+        datetime,       // DATETIME, TIMESTAMP
+        time            // TIME
+        >;
+
+    variant_type data;
+
+    field_impl() = default;
+
+    template <typename... Args>
+    field_impl(Args&&... args) noexcept(std::is_nothrow_constructible<variant_type, Args...>::value)
+        : data(std::forward<Args>(args)...)
+    {
+    }
+
+    field_kind kind() const noexcept { return static_cast<field_kind>(data.index()); }
+
+    template <typename T>
+    const T& as() const
+    {
+        const T* res = boost::variant2::get_if<T>(&data);
+        if (!res)
+            BOOST_THROW_EXCEPTION(bad_field_access());
+        return *res;
+    }
+
+    template <typename T>
+    T& as()
+    {
+        T* res = boost::variant2::get_if<T>(&data);
+        if (!res)
+            BOOST_THROW_EXCEPTION(bad_field_access());
+        return *res;
+    }
+
+    template <typename T>
+    const T& get() const noexcept
+    {
+        constexpr auto I = mp11::mp_find<variant_type, T>::value;
+        return boost::variant2::unsafe_get<I>(data);
+    }
+
+    template <typename T>
+    T& get() noexcept
+    {
+        constexpr auto I = mp11::mp_find<variant_type, T>::value;
+        return boost::variant2::unsafe_get<I>(data);
+    }
+};
+
+}  // namespace detail
+}  // namespace mysql
+}  // namespace boost
+
+#endif