ClickHouse/dbms/include/DB/Columns/ColumnSet.h
2012-08-27 05:13:14 +00:00

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#pragma once
#include <DB/Columns/ColumnConst.h>
#include <DB/Interpreters/Set.h>
namespace DB
{
/** Столбец, содержащий множество значений в секции IN.
* Ведёт себя как столбец-константа (так как множество одно, а не своё на каждую строку).
* Значение у этого столбца нестандартное, поэтому его невозможно получить через обычный интерфейс.
*/
class ColumnSet : public IColumn
{
public:
ColumnSet(size_t s_, SetPtr data_) : s(s_), data(data_) {}
std::string getName() const { return "ColumnSet"; }
ColumnPtr cloneEmpty() const { return new ColumnSet(0, NULL); }
size_t size() const { return s; }
Field operator[](size_t n) const { throw Exception("Cannot get value from ColumnSet", ErrorCodes::NOT_IMPLEMENTED); }
void cut(size_t start, size_t length) { s = length; }
void clear() { s = 0; data = NULL; }
void insert(const Field & x) { throw Exception("Cannot insert element into ColumnSet", ErrorCodes::NOT_IMPLEMENTED); }
void insertDefault() { ++s; }
size_t byteSize() const { return 0; }
int compareAt(size_t n, size_t m, const IColumn & rhs_) const { return 0; }
void filter(const Filter & filt)
{
size_t new_size = 0;
for (Filter::const_iterator it = filt.begin(); it != filt.end(); ++it)
if (*it)
++new_size;
s = new_size;
}
void permute(const Permutation & perm)
{
if (s != perm.size())
throw Exception("Size of permutation doesn't match size of column.", ErrorCodes::SIZES_OF_COLUMNS_DOESNT_MATCH);
}
Permutation getPermutation() const
{
Permutation res(s);
for (size_t i = 0; i < s; ++i)
res[i] = i;
return res;
}
void replicate(const Offsets_t & offsets)
{
if (s != offsets.size())
throw Exception("Size of offsets doesn't match size of column.", ErrorCodes::SIZES_OF_COLUMNS_DOESNT_MATCH);
}
SetPtr & getData() { return data; }
const SetPtr & getData() const { return data; }
private:
size_t s;
SetPtr data;
};
}