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sqlpp11/include/sqlpp11/limit.h

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/*
* Copyright (c) 2013, 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_LIMIT_H
#define SQLPP_LIMIT_H
#include <ostream>
#include <sqlpp11/select_fwd.h>
#include <sqlpp11/type_traits.h>
namespace sqlpp
{
template<typename Limit>
struct limit_t
{
using _is_limit = std::true_type;
static_assert(is_integral_t<Limit>::value, "limit requires an integral value or integral parameter");
Limit _limit;
};
template<typename Context, typename Limit>
struct interpreter_t<Context, limit_t<Limit>>
{
using T = limit_t<Limit>;
static Context& _(const T& t, Context& context)
{
context << " LIMIT ";
interpret(t._limit, context);
return context;
}
};
struct dynamic_limit_t
{
using _is_limit = std::true_type;
using _is_dynamic = std::true_type;
void set(std::size_t limit)
{
_limit = limit;
}
std::size_t _limit;
};
template<typename Context>
struct interpreter_t<Context, dynamic_limit_t>
{
using T = dynamic_limit_t;
static Context& _(const T& t, Context& context)
{
if (t._limit > 0)
context << " LIMIT " << t._limit;
return context;
}
};
}
#endif