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106 lines
3.2 KiB
C++
106 lines
3.2 KiB
C++
/*
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* Copyright (c) 2013-2015, 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 <sqlpp11/type_traits.h>
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#include <sqlpp11/char_sequence.h>
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namespace sqlpp
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{
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struct min_alias_t
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{
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struct _alias_t
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{
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static constexpr const char _literal[] = "min_";
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using _name_t = sqlpp::make_char_sequence<sizeof(_literal), _literal>;
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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()()
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{
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return min;
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}
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const T& operator()() const
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{
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return min;
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}
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};
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};
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};
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template <typename Expr>
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struct min_t : public expression_operators<min_t<Expr>, value_type_of<Expr>>, public alias_operators<min_t<Expr>>
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{
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using _traits = make_traits<value_type_of<Expr>, tag::is_expression, tag::is_selectable>;
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using _nodes = detail::type_vector<Expr, aggregate_function>;
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using _can_be_null = std::true_type;
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using _is_aggregate_expression = std::true_type;
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using _auto_alias_t = min_alias_t;
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min_t(Expr expr) : _expr(expr)
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{
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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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Expr _expr;
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};
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template <typename Context, typename Expr>
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struct serializer_t<Context, min_t<Expr>>
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{
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using _serialize_check = serialize_check_of<Context, Expr>;
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using T = min_t<Expr>;
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static Context& _(const T& t, Context& context)
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{
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context << "MIN(";
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serialize(t._expr, context);
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context << ")";
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return context;
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}
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};
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template <typename T>
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auto min(T t) -> min_t<wrap_operand_t<T>>
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{
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static_assert(not contains_aggregate_function_t<wrap_operand_t<T>>::value,
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"min() cannot be used on an aggregate function");
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static_assert(is_expression_t<wrap_operand_t<T>>::value, "min() requires an expression as argument");
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return {t};
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}
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}
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#endif
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