0
0
mirror of https://github.com/rbock/sqlpp11.git synced 2024-11-16 12:51:13 +08:00
sqlpp11/include/sqlpp11/sum.h
2014-07-28 06:54:54 +02:00

105 lines
3.3 KiB
C++

/*
* Copyright (c) 2013-2014, 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 SQLPP_SUM_H
#define SQLPP_SUM_H
#include <sqlpp11/type_traits.h>
namespace sqlpp
{
template<typename Flag, typename Expr>
struct sum_t: public value_type_of<Expr>::template expression_operators<sum_t<Flag, Expr>>,
public alias_operators<sum_t<Flag, Expr>>
{
using _traits = make_traits<value_type_of<Expr>, ::sqlpp::tag::is_expression, ::sqlpp::tag::is_named_expression>;
using _recursive_traits = make_recursive_traits<Expr>;
static_assert(is_noop<Flag>::value or std::is_same<sqlpp::distinct_t, Flag>::value, "sum() used with flag other than 'distinct'");
static_assert(is_numeric_t<Expr>::value, "sum() requires a numeric expression as argument");
struct _name_t
{
static constexpr const char* _get_name() { return "SUM"; }
template<typename T>
struct _member_t
{
T sum;
T& operator()() { return sum; }
const T& operator()() const { return sum; }
};
};
sum_t(Expr expr):
_expr(expr)
{}
sum_t(const sum_t&) = default;
sum_t(sum_t&&) = default;
sum_t& operator=(const sum_t&) = default;
sum_t& operator=(sum_t&&) = default;
~sum_t() = default;
Expr _expr;
};
template<typename Context, typename Flag, typename Expr>
struct serializer_t<Context, sum_t<Flag, Expr>>
{
using T = sum_t<Flag, Expr>;
static Context& _(const T& t, Context& context)
{
context << "SUM(";
if (std::is_same<sqlpp::distinct_t, Flag>::value)
{
serialize(Flag(), context);
context << ' ';
}
serialize(t._expr, context);
context << ")";
return context;
}
};
template<typename T>
auto sum(T t) -> sum_t<noop, wrap_operand_t<T>>
{
static_assert(is_numeric_t<wrap_operand_t<T>>::value, "sum() requires a numeric expression as argument");
return { t };
}
template<typename T>
auto sum(const sqlpp::distinct_t&, T t) -> sum_t<sqlpp::distinct_t, wrap_operand_t<T>>
{
static_assert(is_numeric_t<wrap_operand_t<T>>::value, "sum() requires a numeric expression as argument");
return { t };
}
}
#endif