ClickHouse/dbms/Functions/array/arrayCount.cpp
Ivan 97f2a2213e
Move all folders inside /dbms one level up (#9974)
* Move some code outside dbms/src folder
* Fix paths
2020-04-02 02:51:21 +03:00

90 lines
2.7 KiB
C++

#include <DataTypes/DataTypesNumber.h>
#include <Columns/ColumnsNumber.h>
#include "FunctionArrayMapped.h"
#include <Functions/FunctionFactory.h>
namespace DB
{
namespace ErrorCodes
{
extern const int ILLEGAL_COLUMN;
}
/** arrayCount(x1,...,xn -> expression, array1,...,arrayn) - for how many elements of the array the expression is true.
* An overload of the form f(array) is available, which works in the same way as f(x -> x, array).
*/
struct ArrayCountImpl
{
static bool needBoolean() { return true; }
static bool needExpression() { return false; }
static bool needOneArray() { return false; }
static DataTypePtr getReturnType(const DataTypePtr & /*expression_return*/, const DataTypePtr & /*array_element*/)
{
return std::make_shared<DataTypeUInt32>();
}
static ColumnPtr execute(const ColumnArray & array, ColumnPtr mapped)
{
const ColumnUInt8 * column_filter = typeid_cast<const ColumnUInt8 *>(&*mapped);
if (!column_filter)
{
auto column_filter_const = checkAndGetColumnConst<ColumnUInt8>(&*mapped);
if (!column_filter_const)
throw Exception("Unexpected type of filter column", ErrorCodes::ILLEGAL_COLUMN);
if (column_filter_const->getValue<UInt8>())
{
const IColumn::Offsets & offsets = array.getOffsets();
auto out_column = ColumnUInt32::create(offsets.size());
ColumnUInt32::Container & out_counts = out_column->getData();
size_t pos = 0;
for (size_t i = 0; i < offsets.size(); ++i)
{
out_counts[i] = offsets[i] - pos;
pos = offsets[i];
}
return out_column;
}
else
return DataTypeUInt32().createColumnConst(array.size(), 0u);
}
const IColumn::Filter & filter = column_filter->getData();
const IColumn::Offsets & offsets = array.getOffsets();
auto out_column = ColumnUInt32::create(offsets.size());
ColumnUInt32::Container & out_counts = out_column->getData();
size_t pos = 0;
for (size_t i = 0; i < offsets.size(); ++i)
{
size_t count = 0;
for (; pos < offsets[i]; ++pos)
{
if (filter[pos])
++count;
}
out_counts[i] = count;
}
return out_column;
}
};
struct NameArrayCount { static constexpr auto name = "arrayCount"; };
using FunctionArrayCount = FunctionArrayMapped<ArrayCountImpl, NameArrayCount>;
void registerFunctionArrayCount(FunctionFactory & factory)
{
factory.registerFunction<FunctionArrayCount>();
}
}