mirror of
https://github.com/facebook/rocksdb.git
synced 2024-11-26 16:30:56 +00:00
9cd221094c
Summary: Add appropriate LICENSE and Copyright message. Test Plan: make check Reviewers: CC: Task ID: # Blame Rev:
72 lines
1.5 KiB
C++
72 lines
1.5 KiB
C++
// Copyright (c) 2013, Facebook, Inc. All rights reserved.
|
|
// This source code is licensed under the BSD-style license found in the
|
|
// LICENSE file in the root directory of this source tree. An additional grant
|
|
// of patent rights can be found in the PATENTS file in the same directory.
|
|
//
|
|
#pragma once
|
|
#include <cassert>
|
|
|
|
namespace rocksdb {
|
|
|
|
class BitSet {
|
|
public:
|
|
/**
|
|
* Create a bit set of numBits, with the bits set to either true or false.
|
|
*/
|
|
explicit BitSet(size_t numBits, bool initial=false)
|
|
: numBits_(numBits),
|
|
data_(numWords(), initial ? ~0UL : 0UL) {
|
|
}
|
|
|
|
/**
|
|
* Set bit b to 1.
|
|
*/
|
|
void set(size_t b) {
|
|
assert(b >= 0 && b < numBits_);
|
|
data_[word(b)] |= wordOffsetMask(b);
|
|
}
|
|
|
|
/**
|
|
* Set bit b to 0;
|
|
*/
|
|
void reset(size_t b) {
|
|
assert(b >= 0 && b < numBits_);
|
|
data_[word(b)] &= ~wordOffsetMask(b);
|
|
}
|
|
|
|
/**
|
|
* Get a bit.
|
|
*/
|
|
bool test(int b) const {
|
|
return data_[word(b)] & wordOffsetMask(b);
|
|
}
|
|
|
|
/**
|
|
* Return the size of the BitSet, in bits.
|
|
*/
|
|
size_t size() const {
|
|
return numBits_;
|
|
}
|
|
|
|
private:
|
|
|
|
inline size_t numWords() const {
|
|
if (numBits_ == 0) return 0;
|
|
return 1 + (numBits_-1) / (8*sizeof(unsigned long));
|
|
}
|
|
inline static size_t word(int b) {
|
|
return b / (8*sizeof(unsigned long));
|
|
}
|
|
inline static int wordOffset(int b) {
|
|
return b % (8*sizeof(unsigned long));
|
|
}
|
|
inline static unsigned long wordOffsetMask(int b) {
|
|
return 1UL << wordOffset(b);
|
|
}
|
|
|
|
size_t numBits_;
|
|
std::vector<unsigned long> data_;
|
|
};
|
|
|
|
} // namespace facebook
|