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115 lines
3.7 KiB
C++
115 lines
3.7 KiB
C++
#include <Columns/ColumnFixedString.h>
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#include <DataTypes/DataTypeFixedString.h>
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#include <Functions/FunctionFactory.h>
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#include <Functions/FunctionHelpers.h>
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#include <Functions/IFunction.h>
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#include <Functions/PerformanceAdaptors.h>
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#include <Functions/FunctionsRandom.h>
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#include <pcg_random.hpp>
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#include <Common/randomSeed.h>
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#include <base/arithmeticOverflow.h>
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#include <base/unaligned.h>
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#include <base/defines.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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extern const int ILLEGAL_COLUMN;
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extern const int DECIMAL_OVERFLOW;
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}
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namespace
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{
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/* Generate random fixed string with fully random bytes (including zero). */
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template <typename RandImpl>
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class FunctionRandomFixedStringImpl : public IFunction
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{
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public:
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static constexpr auto name = "randomFixedString";
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String getName() const override { return name; }
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bool isVariadic() const override { return false; }
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bool isSuitableForShortCircuitArgumentsExecution(const DataTypesWithConstInfo & /*arguments*/) const override { return false; }
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size_t getNumberOfArguments() const override { return 1; }
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DataTypePtr getReturnTypeImpl(const ColumnsWithTypeAndName & arguments) const override
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{
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if (!isUInt(arguments[0].type))
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throw Exception(ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT, "First argument for function {} must be unsigned integer", getName());
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if (!arguments[0].column || !isColumnConst(*arguments[0].column))
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throw Exception(ErrorCodes::ILLEGAL_COLUMN, "First argument for function {} must be constant", getName());
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const size_t n = assert_cast<const ColumnConst &>(*arguments[0].column).getValue<UInt64>();
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return std::make_shared<DataTypeFixedString>(n);
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}
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bool isDeterministic() const override { return false; }
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bool isDeterministicInScopeOfQuery() const override { return false; }
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ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr &, size_t input_rows_count) const override
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{
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const size_t n = assert_cast<const ColumnConst &>(*arguments[0].column).getValue<UInt64>();
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auto col_to = ColumnFixedString::create(n);
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ColumnFixedString::Chars & data_to = col_to->getChars();
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if (input_rows_count == 0)
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return col_to;
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size_t total_size;
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if (common::mulOverflow(input_rows_count, n, total_size))
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throw Exception(ErrorCodes::DECIMAL_OVERFLOW, "Decimal math overflow");
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/// Fill random bytes.
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data_to.resize(total_size);
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RandImpl::execute(reinterpret_cast<char *>(data_to.data()), total_size);
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return col_to;
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}
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};
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class FunctionRandomFixedString : public FunctionRandomFixedStringImpl<TargetSpecific::Default::RandImpl>
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{
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public:
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explicit FunctionRandomFixedString(ContextPtr context) : selector(context)
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{
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selector.registerImplementation<TargetArch::Default,
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FunctionRandomFixedStringImpl<TargetSpecific::Default::RandImpl>>();
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#if USE_MULTITARGET_CODE
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selector.registerImplementation<TargetArch::AVX2,
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FunctionRandomFixedStringImpl<TargetSpecific::AVX2::RandImpl>>();
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#endif
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}
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ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr & result_type, size_t input_rows_count) const override
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{
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return selector.selectAndExecute(arguments, result_type, input_rows_count);
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}
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static FunctionPtr create(ContextPtr context)
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{
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return std::make_shared<FunctionRandomFixedString>(context);
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}
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private:
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ImplementationSelector<IFunction> selector;
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};
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}
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REGISTER_FUNCTION(RandomFixedString)
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{
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factory.registerFunction<FunctionRandomFixedString>();
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}
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}
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