ClickHouse/dbms/include/DB/Functions/FunctionsReinterpret.h

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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 чисел и дат в строки, содержащие тот же набор байт в машинном представлении, и обратно.
*/
template<typename Name>
class FunctionReinterpretAsStringImpl : 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 "
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+ toString(arguments.size()) + ", should be 1.",
ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
const IDataType * type = &*arguments[0];
if (!type->isNumeric() &&
!dynamic_cast<const DataTypeDate *>(type) &&
!dynamic_cast<const DataTypeDateTime *>(type))
throw Exception("Cannot reinterpret " + type->getName() + " as String", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
return new DataTypeString;
}
template<typename T>
bool executeType(Block & block, const ColumnNumbers & arguments, size_t result)
{
if (const ColumnVector<T> * col_from = dynamic_cast<const ColumnVector<T> *>(&*block.getByPosition(arguments[0]).column))
{
ColumnString * col_to = new ColumnString;
block.getByPosition(result).column = col_to;
const typename ColumnVector<T>::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 * (sizeof(T) + 1));
offsets_to.resize(size);
int pos = 0;
for (size_t i = 0; i < size; ++i)
{
memcpy(&data_to[pos], &vec_from[i], sizeof(T));
int len = sizeof(T);
while (len > 0 && data_to[pos + len - 1] == '\0')
--len;
pos += len;
data_to[pos++] = '\0';
offsets_to[i] = pos;
}
data_to.resize(pos);
}
else if (const ColumnConst<T> * col_from = dynamic_cast<const ColumnConst<T> *>(&*block.getByPosition(arguments[0]).column))
{
std::string res(reinterpret_cast<const char *>(&col_from->getData()), sizeof(T));
while (!res.empty() && res[res.length() - 1] == '\0')
res.erase(res.end() - 1);
block.getByPosition(result).column = new ColumnConstString(col_from->size(), res);
}
else
{
return false;
}
return true;
}
/// Выполнить функцию над блоком.
void execute(Block & block, const ColumnNumbers & arguments, size_t result)
{
if (!( executeType<UInt8>(block, arguments, result)
|| executeType<UInt16>(block, arguments, result)
|| executeType<UInt32>(block, arguments, result)
|| executeType<UInt64>(block, arguments, result)
|| executeType<Int8>(block, arguments, result)
|| executeType<Int16>(block, arguments, result)
|| executeType<Int32>(block, arguments, result)
|| executeType<Int64>(block, arguments, result)
|| executeType<Float32>(block, arguments, result)
|| executeType<Float64>(block, arguments, result)))
throw Exception("Illegal column " + block.getByPosition(arguments[0]).column->getName()
+ " of argument of function " + getName(),
ErrorCodes::ILLEGAL_COLUMN);
}
};
template<typename ToDataType, typename Name>
class FunctionReinterpretStringAs : public IFunction
{
public:
typedef typename ToDataType::FieldType ToFieldType;
/// 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 "
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+ toString(arguments.size()) + ", should be 1.",
ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
const IDataType * type = &*arguments[0];
if (!dynamic_cast<const DataTypeString *>(type) &&
!dynamic_cast<const DataTypeFixedString *>(type))
throw Exception("Cannot reinterpret " + type->getName() + " as " + ToDataType().getName(), ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
return new ToDataType;
}
/// Выполнить функцию над блоком.
void execute(Block & block, const ColumnNumbers & arguments, size_t result)
{
if (ColumnString * col_from = dynamic_cast<ColumnString *>(&*block.getByPosition(arguments[0]).column))
{
ColumnVector<ToFieldType> * col_res = new ColumnVector<ToFieldType>;
block.getByPosition(result).column = col_res;
ColumnString::Chars_t & data_from = col_from->getChars();
ColumnString::Offsets_t & offsets_from = col_from->getOffsets();
size_t size = offsets_from.size();
typename ColumnVector<ToFieldType>::Container_t & vec_res = col_res->getData();
vec_res.resize(size);
size_t offset = 0;
for (size_t i = 0; i < size; ++i)
{
ToFieldType value = 0;
memcpy(&value, &data_from[offset], std::min(sizeof(ToFieldType), offsets_from[i] - offset - 1));
vec_res[i] = value;
offset = offsets_from[i];
}
}
else if (ColumnFixedString * col_from = dynamic_cast<ColumnFixedString *>(&*block.getByPosition(arguments[0]).column))
{
ColumnVector<ToFieldType> * col_res = new ColumnVector<ToFieldType>;
block.getByPosition(result).column = col_res;
ColumnString::Chars_t & data_from = col_from->getChars();
size_t step = col_from->getN();
size_t size = data_from.size() / step;
typename ColumnVector<ToFieldType>::Container_t & vec_res = col_res->getData();
vec_res.resize(size);
size_t offset = 0;
size_t copy_size = std::min(step, sizeof(ToFieldType));
for (size_t i = 0; i < size; ++i)
{
ToFieldType value = 0;
memcpy(&value, &data_from[offset], copy_size);
vec_res[i] = value;
offset += step;
}
}
else if (ColumnConst<String> * col = dynamic_cast<ColumnConst<String> *>(&*block.getByPosition(arguments[0]).column))
{
ToFieldType value = 0;
const String & str = col->getData();
memcpy(&value, str.data(), std::min(sizeof(ToFieldType), str.length()));
ColumnConst<ToFieldType> * col_res = new ColumnConst<ToFieldType>(col->size(), value);
block.getByPosition(result).column = col_res;
}
else
{
throw Exception("Illegal column " + block.getByPosition(arguments[0]).column->getName()
+ " of argument of function " + getName(),
ErrorCodes::ILLEGAL_COLUMN);
}
}
};
struct NameReinterpretAsUInt8 { static const char * get() { return "reinterpretAsUInt8"; } };
struct NameReinterpretAsUInt16 { static const char * get() { return "reinterpretAsUInt16"; } };
struct NameReinterpretAsUInt32 { static const char * get() { return "reinterpretAsUInt32"; } };
struct NameReinterpretAsUInt64 { static const char * get() { return "reinterpretAsUInt64"; } };
struct NameReinterpretAsInt8 { static const char * get() { return "reinterpretAsInt8"; } };
struct NameReinterpretAsInt16 { static const char * get() { return "reinterpretAsInt16"; } };
struct NameReinterpretAsInt32 { static const char * get() { return "reinterpretAsInt32"; } };
struct NameReinterpretAsInt64 { static const char * get() { return "reinterpretAsInt64"; } };
struct NameReinterpretAsFloat32 { static const char * get() { return "reinterpretAsFloat32"; } };
struct NameReinterpretAsFloat64 { static const char * get() { return "reinterpretAsFloat64"; } };
struct NameReinterpretAsDate { static const char * get() { return "reinterpretAsDate"; } };
struct NameReinterpretAsDateTime { static const char * get() { return "reinterpretAsDateTime"; } };
struct NameReinterpretAsString { static const char * get() { return "reinterpretAsString"; } };
typedef FunctionReinterpretStringAs<DataTypeUInt8, NameReinterpretAsUInt8> FunctionReinterpretAsUInt8;
typedef FunctionReinterpretStringAs<DataTypeUInt16, NameReinterpretAsUInt16> FunctionReinterpretAsUInt16;
typedef FunctionReinterpretStringAs<DataTypeUInt32, NameReinterpretAsUInt32> FunctionReinterpretAsUInt32;
typedef FunctionReinterpretStringAs<DataTypeUInt64, NameReinterpretAsUInt64> FunctionReinterpretAsUInt64;
typedef FunctionReinterpretStringAs<DataTypeInt8, NameReinterpretAsInt8> FunctionReinterpretAsInt8;
typedef FunctionReinterpretStringAs<DataTypeInt16, NameReinterpretAsInt16> FunctionReinterpretAsInt16;
typedef FunctionReinterpretStringAs<DataTypeInt32, NameReinterpretAsInt32> FunctionReinterpretAsInt32;
typedef FunctionReinterpretStringAs<DataTypeInt64, NameReinterpretAsInt64> FunctionReinterpretAsInt64;
typedef FunctionReinterpretStringAs<DataTypeFloat32, NameReinterpretAsFloat32> FunctionReinterpretAsFloat32;
typedef FunctionReinterpretStringAs<DataTypeFloat64, NameReinterpretAsFloat64> FunctionReinterpretAsFloat64;
typedef FunctionReinterpretStringAs<DataTypeDate, NameReinterpretAsDate> FunctionReinterpretAsDate;
typedef FunctionReinterpretStringAs<DataTypeDateTime, NameReinterpretAsDateTime> FunctionReinterpretAsDateTime;
typedef FunctionReinterpretAsStringImpl<NameReinterpretAsString> FunctionReinterpretAsString;
}