ClickHouse/dbms/include/DB/Columns/IColumnDummy.h

116 lines
3.8 KiB
C++

#pragma once
#include <DB/Columns/IColumn.h>
#include <DB/Columns/ColumnsCommon.h>
namespace DB
{
namespace ErrorCodes
{
extern const int SIZES_OF_COLUMNS_DOESNT_MATCH;
extern const int NOT_IMPLEMENTED;
}
/** Base class for columns-constants that contain a value that is not in the `Field`.
* Not a full-fledged column and is used in a special way.
*/
class IColumnDummy : public IColumn
{
public:
IColumnDummy(size_t s_) : s(s_) {}
virtual ColumnPtr cloneDummy(size_t s_) const = 0;
ColumnPtr cloneResized(size_t s_) const override { return cloneDummy(s_); }
bool isConst() const override { return true; }
size_t size() const override { return s; }
void insertDefault() override { ++s; }
void popBack(size_t n) override { s -= n; }
size_t byteSize() const override { return 0; }
size_t allocatedSize() const override { return 0; }
int compareAt(size_t n, size_t m, const IColumn & rhs_, int nan_direction_hint) const override { return 0; }
Field operator[](size_t n) const override { throw Exception("Cannot get value from " + getName(), ErrorCodes::NOT_IMPLEMENTED); }
void get(size_t n, Field & res) const override { throw Exception("Cannot get value from " + getName(), ErrorCodes::NOT_IMPLEMENTED); };
void insert(const Field & x) override { throw Exception("Cannot insert element into " + getName(), ErrorCodes::NOT_IMPLEMENTED); }
StringRef getDataAt(size_t n) const override { throw Exception("Method getDataAt is not supported for " + getName(), ErrorCodes::NOT_IMPLEMENTED); }
void insertData(const char * pos, size_t length) override { throw Exception("Method insertData is not supported for " + getName(), ErrorCodes::NOT_IMPLEMENTED); }
StringRef serializeValueIntoArena(size_t n, Arena & arena, char const *& begin) const override
{
throw Exception("Method serializeValueIntoArena is not supported for " + getName(), ErrorCodes::NOT_IMPLEMENTED);
}
const char * deserializeAndInsertFromArena(const char * pos) override
{
throw Exception("Method deserializeAndInsertFromArena is not supported for " + getName(), ErrorCodes::NOT_IMPLEMENTED);
}
void updateHashWithValue(size_t n, SipHash & hash) const override
{
throw Exception("Method updateHashWithValue is not supported for " + getName(), ErrorCodes::NOT_IMPLEMENTED);
}
void insertRangeFrom(const IColumn & src, size_t start, size_t length) override
{
s += length;
}
ColumnPtr filter(const Filter & filt, ssize_t result_size_hint) const override
{
return cloneDummy(countBytesInFilter(filt));
}
ColumnPtr permute(const Permutation & perm, size_t limit) const override
{
if (s != perm.size())
throw Exception("Size of permutation doesn't match size of column.", ErrorCodes::SIZES_OF_COLUMNS_DOESNT_MATCH);
return cloneDummy(limit ? std::min(s, limit) : s);
}
void getPermutation(bool reverse, size_t limit, int nan_direction_hint, Permutation & res) const override
{
res.resize(s);
for (size_t i = 0; i < s; ++i)
res[i] = i;
}
ColumnPtr replicate(const Offsets_t & offsets) const override
{
if (s != offsets.size())
throw Exception("Size of offsets doesn't match size of column.", ErrorCodes::SIZES_OF_COLUMNS_DOESNT_MATCH);
return cloneDummy(s == 0 ? 0 : offsets.back());
}
Columns scatter(ColumnIndex num_columns, const Selector & selector) const override
{
if (s != selector.size())
throw Exception("Size of selector doesn't match size of column.", ErrorCodes::SIZES_OF_COLUMNS_DOESNT_MATCH);
std::vector<size_t> counts(num_columns);
for (auto idx : selector)
++counts[idx];
Columns res(num_columns);
for (size_t i = 0; i < num_columns; ++i)
res[i] = cloneResized(counts[i]);
return res;
}
void getExtremes(Field & min, Field & max) const override
{
throw Exception("Method getExtremes is not supported for " + getName(), ErrorCodes::NOT_IMPLEMENTED);
}
private:
size_t s;
};
}