ClickHouse

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#include <type_traits>
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#include <Functions/FunctionFactory.h>
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#include <Functions/FunctionBinaryArithmetic.h>
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#include <base/arithmeticOverflow.h>
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namespace DB
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{
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template <typename A, typename B>
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struct MultiplyImpl
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{
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    using ResultType = typename NumberTraits::ResultOfAdditionMultiplication<A, B>::Type;
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    static const constexpr bool allow_fixed_string = false;
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    static const constexpr bool allow_string_integer = false;
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    template <typename Result = ResultType>
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    static inline NO_SANITIZE_UNDEFINED Result apply(A a, B b)
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    {
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        if constexpr (is_big_int_v<A> || is_big_int_v<B>)
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        {
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            using CastA = std::conditional_t<std::is_floating_point_v<B>, B, A>;
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            using CastB = std::conditional_t<std::is_floating_point_v<A>, A, B>;
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            return static_cast<Result>(static_cast<CastA>(a)) * static_cast<Result>(static_cast<CastB>(b));
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        }
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        else
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            return static_cast<Result>(a) * b;
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    }
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    /// Apply operation and check overflow. It's used for Decimal operations. @returns true if overflowed, false otherwise.
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    template <typename Result = ResultType>
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    static inline bool apply(A a, B b, Result & c)
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    {
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        if constexpr (std::is_same_v<Result, float> || std::is_same_v<Result, double>)
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        {
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            c = static_cast<Result>(a) * b;
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            return false;
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        }
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        else
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            return common::mulOverflow(static_cast<Result>(a), b, c);
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    }
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#if USE_EMBEDDED_COMPILER
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    static constexpr bool compilable = true;
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    static inline llvm::Value * compile(llvm::IRBuilder<> & b, llvm::Value * left, llvm::Value * right, bool)
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    {
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        return left->getType()->isIntegerTy() ? b.CreateMul(left, right) : b.CreateFMul(left, right);
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    }
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#endif
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};
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struct NameMultiply { static constexpr auto name = "multiply"; };
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using FunctionMultiply = BinaryArithmeticOverloadResolver<MultiplyImpl, NameMultiply>;
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REGISTER_FUNCTION(Multiply)
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{
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    factory.registerFunction<FunctionMultiply>();
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}
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}
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