ClickHouse/src/Functions/toTimeZone.cpp
2020-10-14 17:04:50 +03:00

71 lines
2.3 KiB
C++

#include <DataTypes/DataTypeDateTime.h>
#include <DataTypes/DataTypeDateTime64.h>
#include <Functions/IFunctionImpl.h>
#include <Functions/FunctionFactory.h>
#include <Functions/extractTimeZoneFromFunctionArguments.h>
#include <IO/WriteHelpers.h>
#include <Common/assert_cast.h>
namespace DB
{
namespace ErrorCodes
{
extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
extern const int ILLEGAL_TYPE_OF_ARGUMENT;
}
namespace
{
/// Just changes time zone information for data type. The calculation is free.
class FunctionToTimeZone : public IFunction
{
public:
static constexpr auto name = "toTimeZone";
static FunctionPtr create(const Context &) { return std::make_shared<FunctionToTimeZone>(); }
String getName() const override
{
return name;
}
size_t getNumberOfArguments() const override { return 2; }
DataTypePtr getReturnTypeImpl(const ColumnsWithTypeAndName & arguments) const override
{
if (arguments.size() != 2)
throw Exception("Number of arguments for function " + getName() + " doesn't match: passed "
+ toString(arguments.size()) + ", should be 2",
ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
const auto which_type = WhichDataType(arguments[0].type);
if (!which_type.isDateTime() && !which_type.isDateTime64())
throw Exception{"Illegal type " + arguments[0].type->getName() + " of argument of function " + getName() +
". Should be DateTime or DateTime64", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT};
String time_zone_name = extractTimeZoneNameFromFunctionArguments(arguments, 1, 0);
if (which_type.isDateTime())
return std::make_shared<DataTypeDateTime>(time_zone_name);
const auto * date_time64 = assert_cast<const DataTypeDateTime64 *>(arguments[0].type.get());
return std::make_shared<DataTypeDateTime64>(date_time64->getScale(), time_zone_name);
}
void executeImpl(ColumnsWithTypeAndName & columns, const ColumnNumbers & arguments, size_t result, size_t /*input_rows_count*/) const override
{
columns[result].column = columns[arguments[0]].column;
}
};
}
void registerFunctionToTimeZone(FunctionFactory & factory)
{
factory.registerFunction<FunctionToTimeZone>();
}
}