mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-18 05:32:52 +00:00
44 lines
1.2 KiB
C++
44 lines
1.2 KiB
C++
#pragma once
|
|
|
|
#include <double-conversion/double-conversion.h>
|
|
|
|
|
|
namespace DB
|
|
{
|
|
|
|
template <bool emit_decimal_point> struct DoubleToStringConverterFlags
|
|
{
|
|
static constexpr auto flags = double_conversion::DoubleToStringConverter::NO_FLAGS;
|
|
};
|
|
|
|
template <> struct DoubleToStringConverterFlags<true>
|
|
{
|
|
static constexpr auto flags = double_conversion::DoubleToStringConverter::EMIT_TRAILING_DECIMAL_POINT;
|
|
};
|
|
|
|
template <bool emit_decimal_point>
|
|
class DoubleConverter
|
|
{
|
|
DoubleConverter(const DoubleConverter &) = delete;
|
|
DoubleConverter & operator=(const DoubleConverter &) = delete;
|
|
|
|
DoubleConverter() = default;
|
|
|
|
public:
|
|
/** @todo Add commentary on how this constant is deduced.
|
|
* e.g. it's minus sign, integral zero, decimal point, up to 5 leading zeros and kBase10MaximalLength digits. */
|
|
static constexpr auto MAX_REPRESENTATION_LENGTH = 26;
|
|
using BufferType = char[MAX_REPRESENTATION_LENGTH];
|
|
|
|
static const auto & instance()
|
|
{
|
|
static const double_conversion::DoubleToStringConverter instance{
|
|
DoubleToStringConverterFlags<emit_decimal_point>::flags, "inf", "nan", 'e', -6, 21, 6, 1
|
|
};
|
|
|
|
return instance;
|
|
}
|
|
};
|
|
|
|
}
|