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sqlpp11/include/sqlpp11/min.h
2014-06-14 07:49:43 +02:00

92 lines
2.8 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_MIN_H
#define SQLPP_MIN_H
#include <sqlpp11/type_traits.h>
namespace sqlpp
{
template<typename Expr>
struct min_t: public value_type_of<Expr>::template expression_operators<min_t<Expr>>,
public alias_operators<min_t<Expr>>
{
using _traits = make_traits<value_type_of<Expr>, ::sqlpp::tag::expression, ::sqlpp::tag::named_expression>;
using _recursive_traits = make_recursive_traits<Expr>;
static_assert(is_expression_t<Expr>::value, "min() requires a value expression as argument");
struct _name_t
{
static constexpr const char* _get_name() { return "MIN"; }
template<typename T>
struct _member_t
{
T min;
T& operator()() { return min; }
const T& operator()() const { return min; }
};
};
min_t(Expr expr):
_expr(expr)
{}
min_t(const min_t&) = default;
min_t(min_t&&) = default;
min_t& operator=(const min_t&) = default;
min_t& operator=(min_t&&) = default;
~min_t() = default;
Expr _expr;
};
template<typename Context, typename Expr>
struct serializer_t<Context, min_t<Expr>>
{
using T = min_t<Expr>;
static Context& _(const T& t, Context& context)
{
context << "MIN(";
serialize(t._expr, context);
context << ")";
return context;
}
};
template<typename T>
auto min(T t) -> min_t<wrap_operand_t<T>>
{
static_assert(is_expression_t<wrap_operand_t<T>>::value, "min() requires a value expression as argument");
return { t };
}
}
#endif