ClickHouse/dbms/src/Columns/ColumnsCommon.h

#pragma once

#include <Columns/IColumn.h>


/// Common helper methods for implementation of different columns.

namespace DB
{

/// Counts how many bytes of `filt` are greater than zero.
size_t countBytesInFilter(const IColumn::Filter & filt);

/// Returns true, if the memory contains only zeros.
bool memoryIsZero(const void * data, size_t size);


/// The general implementation of `filter` function for ColumnArray and ColumnString.
template <typename T>
void filterArraysImpl(
    const PaddedPODArray<T> & src_elems, const IColumn::Offsets_t & src_offsets,
    PaddedPODArray<T> & res_elems, IColumn::Offsets_t & res_offsets,
    const IColumn::Filter & filt, ssize_t result_size_hint);

/// Same as above, but not fills res_offsets.
template <typename T>
void filterArraysImplOnlyData(
    const PaddedPODArray<T> & src_elems, const IColumn::Offsets_t & src_offsets,
    PaddedPODArray<T> & res_elems,
    const IColumn::Filter & filt, ssize_t result_size_hint);

}