ClickHouse/dbms/Functions/abs.cpp

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#include <Functions/FunctionFactory.h>
#include <Functions/FunctionUnaryArithmetic.h>
#include <DataTypes/NumberTraits.h>
#include <Common/FieldVisitors.h>
namespace DB
{
template <typename A>
struct AbsImpl
{
using ResultType = std::conditional_t<IsDecimalNumber<A>, A, typename NumberTraits::ResultOfAbs<A>::Type>;
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static const constexpr bool allow_fixed_string = false;
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static inline NO_SANITIZE_UNDEFINED ResultType apply(A a)
{
if constexpr (IsDecimalNumber<A>)
return a < 0 ? A(-a) : a;
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else if constexpr (is_integral_v<A> && is_signed_v<A>)
return a < 0 ? static_cast<ResultType>(~a) + 1 : a;
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else if constexpr (is_integral_v<A> && is_unsigned_v<A>)
return static_cast<ResultType>(a);
else if constexpr (std::is_floating_point_v<A>)
return static_cast<ResultType>(std::abs(a));
}
#if USE_EMBEDDED_COMPILER
static constexpr bool compilable = false; /// special type handling, some other time
#endif
};
struct NameAbs { static constexpr auto name = "abs"; };
using FunctionAbs = FunctionUnaryArithmetic<AbsImpl, NameAbs, false>;
template <> struct FunctionUnaryArithmeticMonotonicity<NameAbs>
{
static bool has() { return true; }
static IFunction::Monotonicity get(const Field & left, const Field & right)
{
Float64 left_float = left.isNull() ? -std::numeric_limits<Float64>::infinity() : applyVisitor(FieldVisitorConvertToNumber<Float64>(), left);
Float64 right_float = right.isNull() ? std::numeric_limits<Float64>::infinity() : applyVisitor(FieldVisitorConvertToNumber<Float64>(), right);
if ((left_float < 0 && right_float > 0) || (left_float > 0 && right_float < 0))
return {};
return { true, (left_float > 0) };
}
};
void registerFunctionAbs(FunctionFactory & factory)
{
factory.registerFunction<FunctionAbs>(FunctionFactory::CaseInsensitive);
}
}