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70d1adfe4b
* save format string for NetException * format exceptions * format exceptions 2 * format exceptions 3 * format exceptions 4 * format exceptions 5 * format exceptions 6 * fix * format exceptions 7 * format exceptions 8 * Update MergeTreeIndexGin.cpp * Update AggregateFunctionMap.cpp * Update AggregateFunctionMap.cpp * fix
85 lines
2.3 KiB
C++
85 lines
2.3 KiB
C++
#include <DataTypes/DataTypeString.h>
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#include <Columns/ColumnString.h>
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#include <Functions/FunctionFactory.h>
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#include <Functions/FunctionStringToString.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_COLUMN;
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}
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namespace
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{
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/** Reverse the sequence of code points in a UTF-8 encoded string.
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* The result may not match the expected result, because modifying code points (for example, diacritics) may be applied to another symbols.
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* If the string is not encoded in UTF-8, then the behavior is undefined.
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*/
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struct ReverseUTF8Impl
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{
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static void vector(const ColumnString::Chars & data,
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const ColumnString::Offsets & offsets,
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ColumnString::Chars & res_data,
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ColumnString::Offsets & res_offsets)
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{
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res_data.resize(data.size());
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res_offsets.assign(offsets);
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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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ColumnString::Offset j = prev_offset;
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while (j < offsets[i] - 1)
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{
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if (data[j] < 0xBF)
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{
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res_data[offsets[i] + prev_offset - 2 - j] = data[j];
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j += 1;
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}
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else if (data[j] < 0xE0)
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{
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memcpy(&res_data[offsets[i] + prev_offset - 2 - j - 1], &data[j], 2);
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j += 2;
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}
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else if (data[j] < 0xF0)
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{
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memcpy(&res_data[offsets[i] + prev_offset - 2 - j - 2], &data[j], 3);
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j += 3;
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}
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else
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{
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res_data[offsets[i] + prev_offset - 2 - j] = data[j];
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j += 1;
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}
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}
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res_data[offsets[i] - 1] = 0;
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prev_offset = offsets[i];
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}
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}
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[[noreturn]] static void vectorFixed(const ColumnString::Chars &, size_t, ColumnString::Chars &)
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{
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throw Exception(ErrorCodes::ILLEGAL_COLUMN, "Cannot apply function reverseUTF8 to fixed string.");
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}
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};
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struct NameReverseUTF8
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{
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static constexpr auto name = "reverseUTF8";
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};
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using FunctionReverseUTF8 = FunctionStringToString<ReverseUTF8Impl, NameReverseUTF8, true>;
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}
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REGISTER_FUNCTION(ReverseUTF8)
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{
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factory.registerFunction<FunctionReverseUTF8>();
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}
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}
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