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71 lines
2.1 KiB
C++
71 lines
2.1 KiB
C++
#include <Functions/FunctionFactory.h>
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#include <Functions/FunctionUnaryArithmetic.h>
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#include <DataTypes/NumberTraits.h>
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namespace DB
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{
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namespace ErrorCodes
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{
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extern const int LOGICAL_ERROR;
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extern const int BAD_ARGUMENTS;
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}
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namespace
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{
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/// Working with UInt8: last bit = can be true, previous = can be false (Like src/Storages/MergeTree/BoolMask.h).
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/// This function provides "NOT" operation for BoolMasks by swapping last two bits ("can be true" <-> "can be false").
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template <typename A>
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struct BitSwapLastTwoImpl
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{
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using ResultType = UInt8;
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static constexpr const bool allow_fixed_string = false;
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static const constexpr bool allow_string_integer = false;
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static inline ResultType NO_SANITIZE_UNDEFINED apply([[maybe_unused]] A a)
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{
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if constexpr (!std::is_same_v<A, ResultType>)
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// Should be a logical error, but this function is callable from SQL.
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// Need to investigate this.
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throw DB::Exception("It's a bug! Only UInt8 type is supported by __bitSwapLastTwo.", ErrorCodes::BAD_ARGUMENTS);
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auto little_bits = littleBits<A>(a);
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return static_cast<ResultType>(((little_bits & 1) << 1) | ((little_bits >> 1) & 1));
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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 * arg, bool)
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{
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if (!arg->getType()->isIntegerTy())
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throw Exception("__bitSwapLastTwo expected an integral type", ErrorCodes::LOGICAL_ERROR);
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return b.CreateOr(
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b.CreateShl(b.CreateAnd(arg, 1), 1),
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b.CreateAnd(b.CreateLShr(arg, 1), 1)
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);
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}
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#endif
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};
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struct NameBitSwapLastTwo { static constexpr auto name = "__bitSwapLastTwo"; };
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using FunctionBitSwapLastTwo = FunctionUnaryArithmetic<BitSwapLastTwoImpl, NameBitSwapLastTwo, true>;
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}
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template <> struct FunctionUnaryArithmeticMonotonicity<NameBitSwapLastTwo>
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{
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static bool has() { return false; }
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static IFunction::Monotonicity get(const Field &, const Field &)
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{
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return {};
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}
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};
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void registerFunctionBitSwapLastTwo(FunctionFactory & factory)
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{
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factory.registerFunction<FunctionBitSwapLastTwo>();
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}
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}
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