Files
scylladb/utils/large_bitset.hh
Avi Kivity fcb8d040e8 treewide: use Software Package Data Exchange (SPDX) license identifiers
Instead of lengthy blurbs, switch to single-line, machine-readable
standardized (https://spdx.dev) license identifiers. The Linux kernel
switched long ago, so there is strong precedent.

Three cases are handled: AGPL-only, Apache-only, and dual licensed.
For the latter case, I chose (AGPL-3.0-or-later and Apache-2.0),
reasoning that our changes are extensive enough to apply our license.

The changes we applied mechanically with a script, except to
licenses/README.md.

Closes #9937
2022-01-18 12:15:18 +01:00

65 lines
1.7 KiB
C++

/*
* Copyright (C) 2015-present ScyllaDB
*/
/*
* SPDX-License-Identifier: AGPL-3.0-or-later
*/
// 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;
}
};