mirror of
https://github.com/rbock/sqlpp11.git
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96 lines
2.7 KiB
C++
96 lines
2.7 KiB
C++
/*
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* Copyright (c) 2013, Roland Bock
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without modification,
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* are permitted provided that the following conditions are met:
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*
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* Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* Redistributions in binary form must reproduce the above copyright notice, this
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* list of conditions and the following disclaimer in the documentation and/or
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* other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
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* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
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* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef SQLPP_MIN_H
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#define SQLPP_MIN_H
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#include <sstream>
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#include <sqlpp11/type_traits.h>
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namespace sqlpp
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{
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namespace detail
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{
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template<typename Expr>
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struct min_t: public boolean::template operators<min_t<Expr>>
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{
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static_assert(is_value_t<Expr>::value, "min() requires a value expression as argument");
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struct _value_type: public Expr::_value_type::_base_value_type
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{
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using _is_named_expression = std::true_type;
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};
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struct _name_t
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{
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static constexpr const char* _get_name() { return "MIN"; }
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template<typename T>
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struct _member_t
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{
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T min;
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T& operator()() { return min; }
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const T& operator()() const { return min; }
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};
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};
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min_t(Expr&& expr):
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_expr(std::move(expr))
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{}
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min_t(const Expr& expr):
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_expr(expr)
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{}
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min_t(const min_t&) = default;
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min_t(min_t&&) = default;
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min_t& operator=(const min_t&) = default;
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min_t& operator=(min_t&&) = default;
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~min_t() = default;
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template<typename Db>
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void serialize(std::ostream& os, Db& db) const
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{
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static_assert(Db::_supports_min, "min not supported by current database");
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os << "MIN(";
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_expr.serialize(os, db);
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os << ")";
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}
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private:
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Expr _expr;
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};
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}
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template<typename T>
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auto min(T&& t) -> typename detail::min_t<typename operand_t<T, is_value_t>::type>
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{
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return { std::forward<T>(t) };
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}
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}
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#endif
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