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45 lines
1.1 KiB
C++
45 lines
1.1 KiB
C++
#pragma once
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#include <Parsers/IAST.h>
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namespace DB
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{
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/** Sampling factor in the form 0.1 or 1/10.
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* It's important to save it as a rational number without converting it to IEEE-754.
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*/
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class ASTSampleRatio : public IAST
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{
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public:
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#ifdef __SIZEOF_INT128__
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using BigNum = __uint128_t; /// Must contain the result of multiplying two UInt64.
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#else
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#warning "No uint128_t type. Sampling ratios cannot work correctly."
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using BigNum = uint64_t;
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#endif
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struct Rational
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{
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BigNum numerator = 0;
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BigNum denominator = 1;
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};
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Rational ratio;
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ASTSampleRatio(Rational & ratio_) : ratio(ratio_) {}
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String getID(char delim) const override { return "SampleRatio" + (delim + toString(ratio)); }
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ASTPtr clone() const override { return std::make_shared<ASTSampleRatio>(*this); }
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static String toString(BigNum num);
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static String toString(Rational ratio);
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void formatImpl(const FormatSettings & settings, FormatState &, FormatStateStacked) const override
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{
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settings.ostr << toString(ratio);
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}
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};
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}
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