ClickHouse/dbms/include/DB/Functions/FunctionsConversion.h
2013-09-15 05:51:43 +00:00

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#pragma once
#include <DB/IO/WriteBufferFromVector.h>
#include <DB/IO/ReadBufferFromString.h>
#include <DB/DataTypes/DataTypesNumberFixed.h>
#include <DB/DataTypes/DataTypeString.h>
#include <DB/DataTypes/DataTypeFixedString.h>
#include <DB/DataTypes/DataTypeDate.h>
#include <DB/DataTypes/DataTypeDateTime.h>
#include <DB/Columns/ColumnString.h>
#include <DB/Columns/ColumnFixedString.h>
#include <DB/Columns/ColumnConst.h>
#include <DB/Functions/IFunction.h>
namespace DB
{
/** Функции преобразования типов.
*
* Бывают двух видов:
* - toType - преобразование "естественным образом"; TODO: преобразования из/в FixedString.
*/
/** Преобразование чисел друг в друга, дат/дат-с-временем в числа и наоборот: делается обычным присваиванием.
* (дата внутри хранится как количество дней с какого-то, дата-с-временем - как unix timestamp)
*/
template <typename FromDataType, typename ToDataType, typename Name>
struct ConvertImpl
{
typedef typename FromDataType::FieldType FromFieldType;
typedef typename ToDataType::FieldType ToFieldType;
static void execute(Block & block, const ColumnNumbers & arguments, size_t result)
{
if (const ColumnVector<FromFieldType> * col_from = dynamic_cast<const ColumnVector<FromFieldType> *>(&*block.getByPosition(arguments[0]).column))
{
ColumnVector<ToFieldType> * col_to = new ColumnVector<ToFieldType>;
block.getByPosition(result).column = col_to;
const typename ColumnVector<FromFieldType>::Container_t & vec_from = col_from->getData();
typename ColumnVector<ToFieldType>::Container_t & vec_to = col_to->getData();
size_t size = vec_from.size();
vec_to.resize(size);
for (size_t i = 0; i < size; ++i)
vec_to[i] = vec_from[i];
}
else if (const ColumnConst<FromFieldType> * col_from = dynamic_cast<const ColumnConst<FromFieldType> *>(&*block.getByPosition(arguments[0]).column))
{
block.getByPosition(result).column = new ColumnConst<ToFieldType>(col_from->size(), col_from->getData());
}
else
throw Exception("Illegal column " + block.getByPosition(arguments[0]).column->getName()
+ " of first argument of function " + Name::get(),
ErrorCodes::ILLEGAL_COLUMN);
}
};
/** Преобразование даты в дату-с-временем: добавление нулевого времени.
*/
template <typename Name>
struct ConvertImpl<DataTypeDate, DataTypeDateTime, Name>
{
typedef DataTypeDate::FieldType FromFieldType;
typedef DataTypeDateTime::FieldType ToFieldType;
static void execute(Block & block, const ColumnNumbers & arguments, size_t result)
{
typedef DataTypeDate::FieldType FromFieldType;
DateLUTSingleton & date_lut = DateLUTSingleton::instance();
if (const ColumnVector<FromFieldType> * col_from = dynamic_cast<const ColumnVector<FromFieldType> *>(&*block.getByPosition(arguments[0]).column))
{
ColumnVector<ToFieldType> * col_to = new ColumnVector<ToFieldType>;
block.getByPosition(result).column = col_to;
const typename ColumnVector<FromFieldType>::Container_t & vec_from = col_from->getData();
typename ColumnVector<ToFieldType>::Container_t & vec_to = col_to->getData();
size_t size = vec_from.size();
vec_to.resize(size);
for (size_t i = 0; i < size; ++i)
{
vec_to[i] = date_lut.fromDayNum(DayNum_t(vec_from[i]));
}
}
else if (const ColumnConst<FromFieldType> * col_from = dynamic_cast<const ColumnConst<FromFieldType> *>(&*block.getByPosition(arguments[0]).column))
{
block.getByPosition(result).column = new ColumnConst<ToFieldType>(col_from->size(), date_lut.fromDayNum(DayNum_t(col_from->getData())));
}
else
throw Exception("Illegal column " + block.getByPosition(arguments[0]).column->getName()
+ " of first argument of function " + Name::get(),
ErrorCodes::ILLEGAL_COLUMN);
}
};
/** Преобразование даты-с-временем в дату: отбрасывание времени.
*/
template <typename Name>
struct ConvertImpl<DataTypeDateTime, DataTypeDate, Name>
{
typedef DataTypeDateTime::FieldType FromFieldType;
typedef DataTypeDate::FieldType ToFieldType;
static void execute(Block & block, const ColumnNumbers & arguments, size_t result)
{
DateLUTSingleton & date_lut = DateLUTSingleton::instance();
if (const ColumnVector<FromFieldType> * col_from = dynamic_cast<const ColumnVector<FromFieldType> *>(&*block.getByPosition(arguments[0]).column))
{
ColumnVector<ToFieldType> * col_to = new ColumnVector<ToFieldType>;
block.getByPosition(result).column = col_to;
const typename ColumnVector<FromFieldType>::Container_t & vec_from = col_from->getData();
typename ColumnVector<ToFieldType>::Container_t & vec_to = col_to->getData();
size_t size = vec_from.size();
vec_to.resize(size);
for (size_t i = 0; i < size; ++i)
vec_to[i] = date_lut.toDayNum(vec_from[i]);
}
else if (const ColumnConst<FromFieldType> * col_from = dynamic_cast<const ColumnConst<FromFieldType> *>(&*block.getByPosition(arguments[0]).column))
{
block.getByPosition(result).column = new ColumnConst<ToFieldType>(col_from->size(), date_lut.toDayNum(col_from->getData()));
}
else
throw Exception("Illegal column " + block.getByPosition(arguments[0]).column->getName()
+ " of first argument of function " + Name::get(),
ErrorCodes::ILLEGAL_COLUMN);
}
};
/** Преобразование чисел, дат, дат-с-временем в строки: через форматирование.
*/
template <typename DataType> void formatImpl(typename DataType::FieldType x, WriteBuffer & wb) { writeText(x, wb); }
template <> inline void formatImpl<DataTypeDate>(DataTypeDate::FieldType x, WriteBuffer & wb) { writeDateText(DayNum_t(x), wb); }
template <> inline void formatImpl<DataTypeDateTime>(DataTypeDateTime::FieldType x, WriteBuffer & wb) { writeDateTimeText(x, wb); }
template <typename FromDataType, typename Name>
struct ConvertImpl<FromDataType, DataTypeString, Name>
{
typedef typename FromDataType::FieldType FromFieldType;
static void execute(Block & block, const ColumnNumbers & arguments, size_t result)
{
if (const ColumnVector<FromFieldType> * col_from = dynamic_cast<const ColumnVector<FromFieldType> *>(&*block.getByPosition(arguments[0]).column))
{
ColumnString * col_to = new ColumnString;
block.getByPosition(result).column = col_to;
const typename ColumnVector<FromFieldType>::Container_t & vec_from = col_from->getData();
ColumnString::Chars_t & data_to = col_to->getChars();
ColumnString::Offsets_t & offsets_to = col_to->getOffsets();
size_t size = vec_from.size();
data_to.resize(size * 2);
offsets_to.resize(size);
WriteBufferFromVector<ColumnString::Chars_t> write_buffer(data_to);
for (size_t i = 0; i < size; ++i)
{
formatImpl<FromDataType>(vec_from[i], write_buffer);
writeChar(0, write_buffer);
offsets_to[i] = write_buffer.count();
}
data_to.resize(write_buffer.count());
}
else if (const ColumnConst<FromFieldType> * col_from = dynamic_cast<const ColumnConst<FromFieldType> *>(&*block.getByPosition(arguments[0]).column))
{
std::vector<char> buf;
WriteBufferFromVector<std::vector<char> > write_buffer(buf);
formatImpl<FromDataType>(col_from->getData(), write_buffer);
block.getByPosition(result).column = new ColumnConstString(col_from->size(), std::string(&buf[0], write_buffer.count()));
}
else
throw Exception("Illegal column " + block.getByPosition(arguments[0]).column->getName()
+ " of first argument of function " + Name::get(),
ErrorCodes::ILLEGAL_COLUMN);
}
};
/** Преобразование строк в числа, даты, даты-с-временем: через парсинг.
*/
template <typename DataType> void parseImpl(typename DataType::FieldType & x, ReadBuffer & rb) { readText(x,rb); }
template <> inline void parseImpl<DataTypeDate>(DataTypeDate::FieldType & x, ReadBuffer & rb)
{
DayNum_t tmp(0);
readDateText(tmp, rb);
x = tmp;
}
template <> inline void parseImpl<DataTypeDateTime>(DataTypeDateTime::FieldType & x, ReadBuffer & rb)
{
time_t tmp = 0;
readDateTimeText(tmp, rb);
x = tmp;
}
template <typename ToDataType, typename Name>
struct ConvertImpl<DataTypeString, ToDataType, Name>
{
typedef typename ToDataType::FieldType ToFieldType;
static void execute(Block & block, const ColumnNumbers & arguments, size_t result)
{
if (const ColumnString * col_from = dynamic_cast<const ColumnString *>(&*block.getByPosition(arguments[0]).column))
{
ColumnVector<ToFieldType> * col_to = new ColumnVector<ToFieldType>;
block.getByPosition(result).column = col_to;
const ColumnString::Chars_t & data_from = col_from->getChars();
typename ColumnVector<ToFieldType>::Container_t & vec_to = col_to->getData();
size_t size = col_from->size();
vec_to.resize(size);
ReadBuffer read_buffer(const_cast<char *>(reinterpret_cast<const char *>(&data_from[0])), data_from.size(), 0);
char zero = 0;
for (size_t i = 0; i < size; ++i)
{
parseImpl<ToDataType>(vec_to[i], read_buffer);
readChar(zero, read_buffer);
if (zero != 0)
throw Exception("Cannot parse number from string.", ErrorCodes::CANNOT_PARSE_NUMBER);
}
}
else if (const ColumnConstString * col_from = dynamic_cast<const ColumnConstString *>(&*block.getByPosition(arguments[0]).column))
{
const String & s = col_from->getData();
ReadBufferFromString read_buffer(s);
ToFieldType x = 0;
parseImpl<ToDataType>(x, read_buffer);
block.getByPosition(result).column = new ColumnConst<ToFieldType>(col_from->size(), x);
}
else
throw Exception("Illegal column " + block.getByPosition(arguments[0]).column->getName()
+ " of first argument of function " + Name::get(),
ErrorCodes::ILLEGAL_COLUMN);
}
};
/** Если типы совпадают - просто скопируем ссылку на столбец.
*/
template <typename Name>
struct ConvertImpl<DataTypeString, DataTypeString, Name>
{
static void execute(Block & block, const ColumnNumbers & arguments, size_t result)
{
block.getByPosition(result).column = block.getByPosition(arguments[0]).column;
}
};
template <typename ToDataType, typename Name>
class FunctionConvert : public IFunction
{
public:
/// Получить имя функции.
String getName() const
{
return Name::get();
}
/// Получить тип результата по типам аргументов. Если функция неприменима для данных аргументов - кинуть исключение.
DataTypePtr getReturnType(const DataTypes & arguments) const
{
if (arguments.size() != 1)
throw Exception("Number of arguments for function " + getName() + " doesn't match: passed "
+ toString(arguments.size()) + ", should be 1.",
ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
return new ToDataType;
}
/// Выполнить функцию над блоком.
void execute(Block & block, const ColumnNumbers & arguments, size_t result)
{
IDataType * from_type = &*block.getByPosition(arguments[0]).type;
if (dynamic_cast<const DataTypeUInt8 * >(from_type)) ConvertImpl<DataTypeUInt8, ToDataType, Name>::execute(block, arguments, result);
else if (dynamic_cast<const DataTypeUInt16 * >(from_type)) ConvertImpl<DataTypeUInt16, ToDataType, Name>::execute(block, arguments, result);
else if (dynamic_cast<const DataTypeUInt32 * >(from_type)) ConvertImpl<DataTypeUInt32, ToDataType, Name>::execute(block, arguments, result);
else if (dynamic_cast<const DataTypeUInt64 * >(from_type)) ConvertImpl<DataTypeUInt64, ToDataType, Name>::execute(block, arguments, result);
else if (dynamic_cast<const DataTypeInt8 * >(from_type)) ConvertImpl<DataTypeInt8, ToDataType, Name>::execute(block, arguments, result);
else if (dynamic_cast<const DataTypeInt16 * >(from_type)) ConvertImpl<DataTypeInt16, ToDataType, Name>::execute(block, arguments, result);
else if (dynamic_cast<const DataTypeInt32 * >(from_type)) ConvertImpl<DataTypeInt32, ToDataType, Name>::execute(block, arguments, result);
else if (dynamic_cast<const DataTypeInt64 * >(from_type)) ConvertImpl<DataTypeInt64, ToDataType, Name>::execute(block, arguments, result);
else if (dynamic_cast<const DataTypeFloat32 * >(from_type)) ConvertImpl<DataTypeFloat32, ToDataType, Name>::execute(block, arguments, result);
else if (dynamic_cast<const DataTypeFloat64 * >(from_type)) ConvertImpl<DataTypeFloat64, ToDataType, Name>::execute(block, arguments, result);
else if (dynamic_cast<const DataTypeDate * >(from_type)) ConvertImpl<DataTypeDate, ToDataType, Name>::execute(block, arguments, result);
else if (dynamic_cast<const DataTypeDateTime * >(from_type)) ConvertImpl<DataTypeDateTime, ToDataType, Name>::execute(block, arguments, result);
else if (dynamic_cast<const DataTypeString * >(from_type)) ConvertImpl<DataTypeString, ToDataType, Name>::execute(block, arguments, result);
else
throw Exception("Illegal type " + block.getByPosition(arguments[0]).type->getName() + " of argument of function " + getName(),
ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
}
};
struct NameToUInt8 { static const char * get() { return "toUInt8"; } };
struct NameToUInt16 { static const char * get() { return "toUInt16"; } };
struct NameToUInt32 { static const char * get() { return "toUInt32"; } };
struct NameToUInt64 { static const char * get() { return "toUInt64"; } };
struct NameToInt8 { static const char * get() { return "toInt8"; } };
struct NameToInt16 { static const char * get() { return "toInt16"; } };
struct NameToInt32 { static const char * get() { return "toInt32"; } };
struct NameToInt64 { static const char * get() { return "toInt64"; } };
struct NameToFloat32 { static const char * get() { return "toFloat32"; } };
struct NameToFloat64 { static const char * get() { return "toFloat64"; } };
struct NameToDate { static const char * get() { return "toDate"; } };
struct NameToDateTime { static const char * get() { return "toDateTime"; } };
struct NameToString { static const char * get() { return "toString"; } };
typedef FunctionConvert<DataTypeUInt8, NameToUInt8> FunctionToUInt8;
typedef FunctionConvert<DataTypeUInt16, NameToUInt16> FunctionToUInt16;
typedef FunctionConvert<DataTypeUInt32, NameToUInt32> FunctionToUInt32;
typedef FunctionConvert<DataTypeUInt64, NameToUInt64> FunctionToUInt64;
typedef FunctionConvert<DataTypeInt8, NameToInt8> FunctionToInt8;
typedef FunctionConvert<DataTypeInt16, NameToInt16> FunctionToInt16;
typedef FunctionConvert<DataTypeInt32, NameToInt32> FunctionToInt32;
typedef FunctionConvert<DataTypeInt64, NameToInt64> FunctionToInt64;
typedef FunctionConvert<DataTypeFloat32, NameToFloat32> FunctionToFloat32;
typedef FunctionConvert<DataTypeFloat64, NameToFloat64> FunctionToFloat64;
typedef FunctionConvert<DataTypeDate, NameToDate> FunctionToDate;
typedef FunctionConvert<DataTypeDateTime, NameToDateTime> FunctionToDateTime;
typedef FunctionConvert<DataTypeString, NameToString> FunctionToString;
}