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44 lines
1.1 KiB
C++
44 lines
1.1 KiB
C++
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#pragma once
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#include <double-conversion/double-conversion.h>
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namespace DB
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{
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template <bool emit_decimal_point> struct DoubleToStringConverterFlags
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{
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static constexpr auto flags = double_conversion::DoubleToStringConverter::NO_FLAGS;
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};
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template <> struct DoubleToStringConverterFlags<true>
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{
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static constexpr auto flags = double_conversion::DoubleToStringConverter::EMIT_TRAILING_DECIMAL_POINT;
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};
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template <bool emit_decimal_point>
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class DoubleConverter
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{
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DoubleConverter(const DoubleConverter &) = delete;
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DoubleConverter & operator=(const DoubleConverter &) = delete;
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DoubleConverter() = default;
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public:
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/** @todo Add commentary on how this constant is deduced.
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* e.g. it's minus sign, integral zero, decimal point, up to 5 leading zeros and kBase10MaximalLength digits. */
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static constexpr auto MAX_REPRESENTATION_LENGTH = 26;
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using BufferType = char[MAX_REPRESENTATION_LENGTH];
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static const auto & instance()
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{
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static const double_conversion::DoubleToStringConverter instance{
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DoubleToStringConverterFlags<emit_decimal_point>::flags, "inf", "nan", 'e', -6, 21, 6, 1
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};
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return instance;
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}
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};
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}
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