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sqlpp11/include/sqlpp11/interpret_tuple.h

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3.8 KiB
C++

/*
* Copyright (c) 2013-2015, Roland Bock
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright notice, this
* list of conditions and the following disclaimer in the documentation and/or
* other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef SQLPP11_INTERPRET_TUPLE_H
#define SQLPP11_INTERPRET_TUPLE_H
#include <tuple>
#include <sqlpp11/type_traits.h>
#include <sqlpp11/serialize.h>
#include <sqlpp11/detail/index_sequence.h>
namespace sqlpp
{
template <typename Element, typename Separator, typename Context, typename UseBraces>
static void interpret_tuple_element(
const Element& element, const Separator& separator, Context& context, const UseBraces& /*unused*/, size_t index)
{
if (index)
{
context << separator;
}
if (UseBraces::value)
{
serialize_operand(element, context);
}
else
{
serialize(element, context);
}
}
template <typename Tuple, typename Separator, typename Context, typename UseBraces, size_t... Is>
auto interpret_tuple_impl(const Tuple& t,
const Separator& separator,
Context& context,
const UseBraces& useBraces,
const detail::index_sequence<Is...> &
/*unused*/) -> Context&
{
// Note: A braced-init-list does guarantee the order of evaluation according to 12.6.1 [class.explicit.init]
// paragraph 2 and 8.5.4 [dcl.init.list] paragraph 4.
// See for example: "http://en.cppreference.com/w/cpp/utility/integer_sequence"
// See also: "http://stackoverflow.com/questions/6245735/pretty-print-stdtuple/6245777#6245777"
// Beware of gcc-bug: "http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51253", otherwise an empty swallow struct could
// be used
using swallow = int[];
(void)swallow{0, // workaround against -Wpedantic GCC warning "zero-size array 'int [0]'"
(interpret_tuple_element(std::get<Is>(t), separator, context, useBraces, Is), 0)...};
return context;
}
template <typename Tuple, typename Separator, typename Context>
auto interpret_tuple(const Tuple& t, const Separator& separator, Context& context) -> Context&
{
return interpret_tuple_impl(t, separator, context, std::true_type{},
detail::make_index_sequence<std::tuple_size<Tuple>::value>{});
}
template <typename Tuple, typename Separator, typename Context>
auto interpret_tuple_without_braces(const Tuple& t, const Separator& separator, Context& context) -> Context&
{
return interpret_tuple_impl(t, separator, context, std::false_type{},
detail::make_index_sequence<std::tuple_size<Tuple>::value>{});
}
} // namespace sqlpp
#endif