ClickHouse/base/mysqlxx/Value.h
Ivan b7ef5a699c
Move FastMemcpy to contribs (#9219)
* Get rid of non-existent vectorclass
* Move FastMemcpy to contribs
* Restore comments
* Disable FastMemcpy on non-Linux
* Fix cmake file
* Don't build FastMemcpy for ARM64
* Replace FastMemcpy submodule with its contents
* Fix cmake file
* Move widechar_width to contrib/
* Move sumbur to contrib/
* Move consistent-hashing to contrib/
* Fix UBSan tests
2020-03-13 01:26:16 +03:00

267 lines
9.8 KiB
C++
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

#pragma once
#include <string.h>
#include <stdio.h>
#include <time.h>
#include <math.h>
#include <string>
#include <limits>
#include <common/preciseExp10.h>
#include <common/Types.h>
#include <common/DateLUT.h>
#include <mysqlxx/Types.h>
#include <common/LocalDateTime.h>
namespace mysqlxx
{
class ResultBase;
/** Represents a single value read from MySQL.
* It doesn't owns the value. It's just a wrapper of a pair (const char *, size_t).
* If the UseQueryResult/StoreQueryResult or Connection is destroyed,
* or you have read the next Row while using UseQueryResult, then the object is invalidated.
* Allows to transform (parse) the value to various data types:
* - with getUInt(), getString(), ... (recommended);
* - with template function get<Type>() that is specialized for multiple data types;
* - the template function get<Type> also works for all types that can be constructed from Value
* (it is an extension point);
* - with operator Type() - this is done for compatibility and not recommended because ambiguities possible.
*
* On parsing error, exception is thrown.
* When trying to extract a value that is nullptr, exception is thrown
* - use isNull() method to check.
*
* As time_t is just an alias for integer data type
* to allow to write row[0].get<time_t>(), and expect that the values like '2011-01-01 00:00:00'
* will be successfully parsed according to the current time zone,
* the getUInt method and the corresponding get<>() methods
* are capable of parsing Date and DateTime.
*/
class Value
{
public:
/** Параметр res_ используется только для генерации подробной информации в исключениях.
* Можно передать NULL - тогда подробной информации в исключениях не будет.
*/
Value(const char * data_, size_t length_, const ResultBase * res_) : m_data(data_), m_length(length_), res(res_)
{
}
/// Получить значение bool.
bool getBool() const
{
if (unlikely(isNull()))
throwException("Value is NULL");
return m_length > 0 && m_data[0] != '0';
}
/// Получить беззнаковое целое.
UInt64 getUInt() const
{
if (unlikely(isNull()))
throwException("Value is NULL");
return readUIntText(m_data, m_length);
}
/// Получить целое со знаком или дату или дату-время (в unix timestamp согласно текущей тайм-зоне).
Int64 getInt() const
{
return getIntOrDateTime();
}
/// Получить число с плавающей запятой.
double getDouble() const
{
if (unlikely(isNull()))
throwException("Value is NULL");
return readFloatText(m_data, m_length);
}
/// Получить дату-время (из значения вида '2011-01-01 00:00:00').
LocalDateTime getDateTime() const
{
return LocalDateTime(data(), size());
}
/// Получить дату (из значения вида '2011-01-01' или '2011-01-01 00:00:00').
LocalDate getDate() const
{
return LocalDate(data(), size());
}
/// Получить строку.
std::string getString() const
{
if (unlikely(isNull()))
throwException("Value is NULL");
return std::string(m_data, m_length);
}
/// Является ли NULL.
bool isNull() const
{
return m_data == nullptr;
}
/// Для совместимости (используйте вместо этого метод isNull())
bool is_null() const { return isNull(); }
/** Получить любой поддерживаемый тип (для шаблонного кода).
* Поддерживаются основные типы, а также любые типы с конструктором от Value (для удобства расширения).
*/
template <typename T> T get() const;
/// Для совместимости. Не рекомендуется к использованию, так как неудобен (часто возникают неоднозначности).
template <typename T> operator T() const { return get<T>(); }
const char * data() const { return m_data; }
size_t length() const { return m_length; }
size_t size() const { return m_length; }
bool empty() const { return 0 == m_length; }
private:
const char * m_data;
size_t m_length;
const ResultBase * res;
bool checkDateTime() const
{
return (m_length == 10 || m_length == 19) && m_data[4] == '-' && m_data[7] == '-';
}
time_t getDateTimeImpl() const
{
const auto & date_lut = DateLUT::instance();
if (m_length == 10)
{
return date_lut.makeDate(
(m_data[0] - '0') * 1000 + (m_data[1] - '0') * 100 + (m_data[2] - '0') * 10 + (m_data[3] - '0'),
(m_data[5] - '0') * 10 + (m_data[6] - '0'),
(m_data[8] - '0') * 10 + (m_data[9] - '0'));
}
else if (m_length == 19)
{
return date_lut.makeDateTime(
(m_data[0] - '0') * 1000 + (m_data[1] - '0') * 100 + (m_data[2] - '0') * 10 + (m_data[3] - '0'),
(m_data[5] - '0') * 10 + (m_data[6] - '0'),
(m_data[8] - '0') * 10 + (m_data[9] - '0'),
(m_data[11] - '0') * 10 + (m_data[12] - '0'),
(m_data[14] - '0') * 10 + (m_data[15] - '0'),
(m_data[17] - '0') * 10 + (m_data[18] - '0'));
}
else
throwException("Cannot parse DateTime");
return 0; /// avoid warning.
}
time_t getDateImpl() const
{
const auto & date_lut = DateLUT::instance();
if (m_length == 10 || m_length == 19)
{
return date_lut.makeDate(
(m_data[0] - '0') * 1000 + (m_data[1] - '0') * 100 + (m_data[2] - '0') * 10 + (m_data[3] - '0'),
(m_data[5] - '0') * 10 + (m_data[6] - '0'),
(m_data[8] - '0') * 10 + (m_data[9] - '0'));
}
else
throwException("Cannot parse Date");
return 0; /// avoid warning.
}
Int64 getIntImpl() const
{
return readIntText(m_data, m_length);
}
Int64 getIntOrDateTime() const
{
if (unlikely(isNull()))
throwException("Value is NULL");
if (checkDateTime())
return getDateTimeImpl();
else
return getIntImpl();
}
Int64 getIntOrDate() const
{
if (unlikely(isNull()))
throwException("Value is NULL");
if (checkDateTime())
return getDateImpl();
else
{
const auto & date_lut = DateLUT::instance();
return date_lut.toDate(getIntImpl());
}
}
/// Прочитать беззнаковое целое в простом формате из не-0-terminated строки.
UInt64 readUIntText(const char * buf, size_t length) const;
/// Прочитать знаковое целое в простом формате из не-0-terminated строки.
Int64 readIntText(const char * buf, size_t length) const;
/// Прочитать число с плавающей запятой в простом формате, с грубым округлением, из не-0-terminated строки.
double readFloatText(const char * buf, size_t length) const;
/// Выкинуть исключение с подробной информацией
[[noreturn]] void throwException(const char * text) const;
};
template <> inline bool Value::get<bool >() const { return getBool(); }
template <> inline char Value::get<char >() const { return getInt(); }
template <> inline signed char Value::get<signed char >() const { return getInt(); }
template <> inline unsigned char Value::get<unsigned char >() const { return getUInt(); }
template <> inline char8_t Value::get<char8_t >() const { return getUInt(); }
template <> inline short Value::get<short >() const { return getInt(); }
template <> inline unsigned short Value::get<unsigned short >() const { return getUInt(); }
template <> inline int Value::get<int >() const { return getInt(); }
template <> inline unsigned int Value::get<unsigned int >() const { return getUInt(); }
template <> inline long Value::get<long >() const { return getInt(); }
template <> inline unsigned long Value::get<unsigned long >() const { return getUInt(); }
template <> inline long long Value::get<long long >() const { return getInt(); }
template <> inline unsigned long long Value::get<unsigned long long >() const { return getUInt(); }
template <> inline float Value::get<float >() const { return getDouble(); }
template <> inline double Value::get<double >() const { return getDouble(); }
template <> inline std::string Value::get<std::string >() const { return getString(); }
template <> inline LocalDate Value::get<LocalDate >() const { return getDate(); }
template <> inline LocalDateTime Value::get<LocalDateTime >() const { return getDateTime(); }
template <typename T> inline T Value::get() const { return T(*this); }
inline std::ostream & operator<< (std::ostream & ostr, const Value & x)
{
return ostr.write(x.data(), x.size());
}
}