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73 lines
2.2 KiB
C++
73 lines
2.2 KiB
C++
#include <DataTypes/DataTypeString.h>
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#include <Functions/FunctionFactory.h>
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#include <Functions/FunctionStringOrArrayToT.h>
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#include <Common/UTF8Helpers.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 ILLEGAL_TYPE_OF_ARGUMENT;
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}
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/** If the string is UTF-8 encoded text, it returns the length of the text in code points.
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* (not in characters: the length of the text "ё" can be either 1 or 2, depending on the normalization)
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* (not in characters: the length of the text "" can be either 1 or 2, depending on the normalization)
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* Otherwise, the behavior is undefined.
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*/
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struct LengthUTF8Impl
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{
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static constexpr auto is_fixed_to_constant = false;
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static void vector(const ColumnString::Chars & data, const ColumnString::Offsets & offsets, PaddedPODArray<UInt64> & res)
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{
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size_t size = offsets.size();
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ColumnString::Offset prev_offset = 0;
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for (size_t i = 0; i < size; ++i)
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{
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res[i] = UTF8::countCodePoints(&data[prev_offset], offsets[i] - prev_offset - 1);
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prev_offset = offsets[i];
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}
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}
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static void vector_fixed_to_constant(const ColumnString::Chars & /*data*/, size_t /*n*/, UInt64 & /*res*/)
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{
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}
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static void vector_fixed_to_vector(const ColumnString::Chars & data, size_t n, PaddedPODArray<UInt64> & res)
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{
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size_t size = data.size() / n;
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for (size_t i = 0; i < size; ++i)
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{
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res[i] = UTF8::countCodePoints(&data[i * n], n);
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}
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}
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static void array(const ColumnString::Offsets &, PaddedPODArray<UInt64> &)
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{
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throw Exception("Cannot apply function lengthUTF8 to Array argument", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
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}
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};
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struct NameLengthUTF8
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{
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static constexpr auto name = "lengthUTF8";
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};
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using FunctionLengthUTF8 = FunctionStringOrArrayToT<LengthUTF8Impl, NameLengthUTF8, UInt64>;
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void registerFunctionLengthUTF8(FunctionFactory & factory)
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{
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factory.registerFunction<FunctionLengthUTF8>();
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/// Compatibility aliases.
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factory.registerFunction<FunctionLengthUTF8>("CHAR_LENGTH", FunctionFactory::CaseInsensitive);
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factory.registerFunction<FunctionLengthUTF8>("CHARACTER_LENGTH", FunctionFactory::CaseInsensitive);
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}
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}
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