Files
scylladb/utils/large_bitset.hh
Pavel Solodovnikov 76bea23174 treewide: reduce header interdependencies
Use forward declarations wherever possible.

Signed-off-by: Pavel Solodovnikov <pa.solodovnikov@scylladb.com>

Closes #8813
2021-06-07 15:58:35 +03:00

78 lines
2.3 KiB
C++

/*
* Copyright (C) 2015-present ScyllaDB
*/
/*
* This file is part of Scylla.
*
* Scylla is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Scylla is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Scylla. If not, see <http://www.gnu.org/licenses/>.
*/
// A bitset containing a very large number of bits, so it uses fragmented
// storage in order not to stress the memory allocator.
#pragma once
#include <limits>
#include <seastar/core/preempt.hh>
#include "utils/chunked_vector.hh"
using namespace seastar;
class large_bitset {
using int_type = uint64_t;
static constexpr size_t bits_per_int() {
return std::numeric_limits<int_type>::digits;
}
size_t _nr_bits = 0;
utils::chunked_vector<int_type> _storage;
public:
explicit large_bitset(size_t nr_bits);
explicit large_bitset(size_t nr_bits, utils::chunked_vector<int_type> storage) : _nr_bits(nr_bits), _storage(std::move(storage)) {}
large_bitset(large_bitset&&) = default;
large_bitset(const large_bitset&) = delete;
large_bitset& operator=(const large_bitset&) = delete;
size_t size() const {
return _nr_bits;
}
size_t memory_size() const {
return _storage.memory_size();
}
bool test(size_t idx) const {
auto idx1 = idx / bits_per_int();
idx %= bits_per_int();
auto idx2 = idx;
return (_storage[idx1] >> idx2) & 1;
}
void set(size_t idx) {
auto idx1 = idx / bits_per_int();
idx %= bits_per_int();
auto idx2 = idx;
_storage[idx1] |= int_type(1) << idx2;
}
void clear(size_t idx) {
auto idx1 = idx / bits_per_int();
idx %= bits_per_int();
auto idx2 = idx;
_storage[idx1] &= ~(int_type(1) << idx2);
}
void clear();
const utils::chunked_vector<int_type>& get_storage() const {
return _storage;
}
};