94 lines
2.4 KiB
C++
94 lines
2.4 KiB
C++
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//
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// Copyright (c) 2019-2024 Ruben Perez Hidalgo (rubenperez038 at gmail dot com)
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//
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#ifndef BOOST_MYSQL_DETAIL_TYPING_POS_MAP_HPP
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#define BOOST_MYSQL_DETAIL_TYPING_POS_MAP_HPP
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#include <boost/mysql/field_view.hpp>
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#include <boost/mysql/metadata.hpp>
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#include <boost/mysql/metadata_collection_view.hpp>
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#include <boost/mysql/string_view.hpp>
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#include <boost/assert.hpp>
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#include <boost/config.hpp>
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#include <boost/core/span.hpp>
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#include <cstddef>
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namespace boost {
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namespace mysql {
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namespace detail {
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// These functions map C++ type positions to positions to positions in the DB query
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BOOST_INLINE_CONSTEXPR std::size_t pos_absent = static_cast<std::size_t>(-1);
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using name_table_t = boost::span<const string_view>;
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inline bool has_field_names(name_table_t name_table) noexcept { return !name_table.empty(); }
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inline void pos_map_reset(span<std::size_t> self) noexcept
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{
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for (std::size_t i = 0; i < self.size(); ++i)
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self.data()[i] = pos_absent;
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}
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inline void pos_map_add_field(
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span<std::size_t> self,
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name_table_t name_table,
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std::size_t db_index,
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string_view field_name
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) noexcept
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{
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if (has_field_names(name_table))
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{
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BOOST_ASSERT(self.size() == name_table.size());
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// We're mapping fields by name. Try to find where in our target struct
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// is the current field located
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auto it = std::find(name_table.begin(), name_table.end(), field_name);
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if (it != name_table.end())
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{
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std::size_t cpp_index = it - name_table.begin();
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self[cpp_index] = db_index;
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}
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}
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else
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{
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// We're mapping by position. Any extra trailing fields are discarded
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if (db_index < self.size())
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{
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self[db_index] = db_index;
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}
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}
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}
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inline field_view map_field_view(
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span<const std::size_t> self,
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std::size_t cpp_index,
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span<const field_view> array
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) noexcept
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{
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BOOST_ASSERT(cpp_index < self.size());
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return array[self[cpp_index]];
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}
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inline const metadata& map_metadata(
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span<const std::size_t> self,
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std::size_t cpp_index,
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metadata_collection_view meta
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) noexcept
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{
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BOOST_ASSERT(cpp_index < self.size());
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return meta[self[cpp_index]];
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}
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} // namespace detail
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} // namespace mysql
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} // namespace boost
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#endif
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