1 | #include <Functions/FunctionFactory.h> |
2 | #include <Functions/FunctionUnaryArithmetic.h> |
3 | #include <DataTypes/NumberTraits.h> |
4 | |
5 | namespace DB |
6 | { |
7 | namespace ErrorCodes |
8 | { |
9 | extern const int BAD_CAST; |
10 | } |
11 | |
12 | /// Working with UInt8: last bit = can be true, previous = can be false (Like dbms/src/Storages/MergeTree/BoolMask.h). |
13 | /// This function provides "NOT" operation for BoolMasks by swapping last two bits ("can be true" <-> "can be false"). |
14 | template <typename A> |
15 | struct BitSwapLastTwoImpl |
16 | { |
17 | using ResultType = UInt8; |
18 | |
19 | static inline ResultType NO_SANITIZE_UNDEFINED apply(A a) |
20 | { |
21 | if constexpr (!std::is_same_v<A, ResultType>) |
22 | throw DB::Exception("It's a bug! Only UInt8 type is supported by __bitSwapLastTwo." , ErrorCodes::BAD_CAST); |
23 | return static_cast<ResultType>( |
24 | ((static_cast<ResultType>(a) & 1) << 1) | ((static_cast<ResultType>(a) >> 1) & 1)); |
25 | } |
26 | |
27 | #if USE_EMBEDDED_COMPILER |
28 | static constexpr bool compilable = true; |
29 | |
30 | static inline llvm::Value * compile(llvm::IRBuilder<> & b, llvm::Value * arg, bool) |
31 | { |
32 | if (!arg->getType()->isIntegerTy()) |
33 | throw Exception("__bitSwapLastTwo expected an integral type" , ErrorCodes::LOGICAL_ERROR); |
34 | return b.CreateOr( |
35 | b.CreateShl(b.CreateAnd(arg, 1), 1), |
36 | b.CreateAnd(b.CreateLShr(arg, 1), 1) |
37 | ); |
38 | } |
39 | #endif |
40 | }; |
41 | |
42 | struct NameBitSwapLastTwo { static constexpr auto name = "__bitSwapLastTwo" ; }; |
43 | using FunctionBitSwapLastTwo = FunctionUnaryArithmetic<BitSwapLastTwoImpl, NameBitSwapLastTwo, true>; |
44 | |
45 | template <> struct FunctionUnaryArithmeticMonotonicity<NameBitSwapLastTwo> |
46 | { |
47 | static bool has() { return false; } |
48 | static IFunction::Monotonicity get(const Field &, const Field &) |
49 | { |
50 | return {}; |
51 | } |
52 | }; |
53 | |
54 | void registerFunctionBitSwapLastTwo(FunctionFactory & factory) |
55 | { |
56 | factory.registerFunction<FunctionBitSwapLastTwo>(); |
57 | } |
58 | |
59 | } |
60 | |