ClickHouse/dbms/include/DB/Core/Field.h
2011-10-10 10:05:39 +00:00

194 lines
6.1 KiB
C++

#pragma once
#include <vector>
#include <sstream>
#include <boost/variant.hpp>
#include <boost/variant/recursive_variant.hpp>
#include <boost/variant/static_visitor.hpp>
#include <Poco/NumberFormatter.h>
#include <mysqlxx/mysqlxx.h>
#include <DB/Core/Types.h>
#include <DB/Core/Exception.h>
#include <DB/Core/ErrorCodes.h>
namespace DB
{
using Poco::SharedPtr;
class IAggregateFunction;
/** Типы данных для представления единичного значения произвольного типа в оперативке.
* Внимание! Предпочтительно вместо единичных значений хранить кусочки столбцов. См. Column.h
*/
typedef boost::make_recursive_variant<
Null,
UInt64,
Int64,
Float64,
String,
SharedPtr<IAggregateFunction>, /// Состояние агрегатной функции
std::vector<boost::recursive_variant_> /// Array, Tuple
>::type Field;
typedef std::vector<Field> Array; /// Значение типа "массив"
/** Числовое значение конкретного типа Field */
namespace FieldType
{
enum Enum
{
Null = 0,
UInt64,
Int64,
Float64,
String,
AggregateFunction,
Array
};
}
/** Возвращает true, если вариант - Null */
class FieldVisitorIsNull : public boost::static_visitor<bool>
{
public:
template <typename T> bool operator() (const T & x) const { return false; }
bool operator() (const Null & x) const { return true; }
};
/** Возвращает числовое значение типа */
class FieldVisitorGetType : public boost::static_visitor<FieldType::Enum>
{
public:
FieldType::Enum operator() (const Null & x) const { return FieldType::Null; }
FieldType::Enum operator() (const UInt64 & x) const { return FieldType::UInt64; }
FieldType::Enum operator() (const Int64 & x) const { return FieldType::Int64; }
FieldType::Enum operator() (const Float64 & x) const { return FieldType::Float64; }
FieldType::Enum operator() (const String & x) const { return FieldType::String; }
FieldType::Enum operator() (const SharedPtr<IAggregateFunction> & x) const { return FieldType::AggregateFunction; }
FieldType::Enum operator() (const Array & x) const { return FieldType::Array; }
};
/** Возвращает строковый дамп типа */
class FieldVisitorDump : public boost::static_visitor<std::string>
{
public:
String operator() (const Null & x) const { return "NULL"; }
String operator() (const UInt64 & x) const { return "UInt64_" + Poco::NumberFormatter::format(x); }
String operator() (const Int64 & x) const { return "Int64_" + Poco::NumberFormatter::format(x); }
String operator() (const Float64 & x) const { return "Float64_" + Poco::NumberFormatter::format(x); }
String operator() (const SharedPtr<IAggregateFunction> & x) const { return "AggregateFunction"; }
String operator() (const String & x) const
{
std::stringstream s;
s << mysqlxx::quote << x;
return s.str();
}
String operator() (const Array & x) const
{
std::stringstream s;
s << "Array_[";
for (Array::const_iterator it = x.begin(); it != x.end(); ++it)
{
if (it != x.begin())
s << ", ";
s << boost::apply_visitor(FieldVisitorDump(), *it);
}
s << "]";
return s.str();
}
};
/** Выводит текстовое представление типа, как литерала в SQL запросе */
class FieldVisitorToString : public boost::static_visitor<String>
{
public:
String operator() (const Null & x) const { return "NULL"; }
String operator() (const UInt64 & x) const { return Poco::NumberFormatter::format(x); }
String operator() (const Int64 & x) const { return Poco::NumberFormatter::format(x); }
String operator() (const Float64 & x) const { return Poco::NumberFormatter::format(x); }
String operator() (const SharedPtr<IAggregateFunction> & x) const { return "AggregateFunction"; }
String operator() (const String & x) const
{
std::stringstream s;
s << mysqlxx::quote << x;
return s.str();
}
String operator() (const Array & x) const
{
std::stringstream s;
FieldVisitorToString visitor;
s << "[";
for (Array::const_iterator it = x.begin(); it != x.end(); ++it)
{
if (it != x.begin())
s << ", ";
s << boost::apply_visitor(FieldVisitorToString(), *it);
}
s << "]";
return s.str();
}
};
/** Числовой тип преобразует в указанный. */
template <typename T>
class FieldVisitorConvertToNumber : public boost::static_visitor<T>
{
public:
T operator() (const Null & x) const
{
throw Exception("Cannot convert NULL to " + TypeName<T>::get(), ErrorCodes::CANNOT_CONVERT_TYPE);
}
T operator() (const String & x) const
{
throw Exception("Cannot convert String to " + TypeName<T>::get(), ErrorCodes::CANNOT_CONVERT_TYPE);
}
T operator() (const Array & x) const
{
throw Exception("Cannot convert Array to " + TypeName<T>::get(), ErrorCodes::CANNOT_CONVERT_TYPE);
}
T operator() (const SharedPtr<IAggregateFunction> & x) const
{
throw Exception("Cannot convert AggregateFunctionPtr to " + TypeName<T>::get(), ErrorCodes::CANNOT_CONVERT_TYPE);
}
T operator() (const UInt64 & x) const { return x; }
T operator() (const Int64 & x) const { return x; }
T operator() (const Float64 & x) const { return x; }
};
template <typename T> struct NearestFieldType;
template <> struct NearestFieldType<UInt8> { typedef UInt64 Type; };
template <> struct NearestFieldType<UInt16> { typedef UInt64 Type; };
template <> struct NearestFieldType<UInt32> { typedef UInt64 Type; };
template <> struct NearestFieldType<UInt64> { typedef UInt64 Type; };
template <> struct NearestFieldType<Int8> { typedef Int64 Type; };
template <> struct NearestFieldType<Int16> { typedef Int64 Type; };
template <> struct NearestFieldType<Int32> { typedef Int64 Type; };
template <> struct NearestFieldType<Int64> { typedef Int64 Type; };
template <> struct NearestFieldType<Float32> { typedef Float64 Type; };
template <> struct NearestFieldType<Float64> { typedef Float64 Type; };
template <> struct NearestFieldType<String> { typedef String Type; };
}