2013-11-27 23:27:02 +01:00
|
|
|
// 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 <atomic>
|
|
|
|
#include <memory>
|
|
|
|
|
|
|
|
namespace rocksdb {
|
|
|
|
|
|
|
|
class Slice;
|
|
|
|
|
|
|
|
class DynamicBloom {
|
|
|
|
public:
|
|
|
|
// total_bits: fixed total bits for the bloom
|
|
|
|
// num_probes: number of hash probes for a single key
|
2014-03-28 17:21:20 +01:00
|
|
|
// cl_per_block: block size in cache lines. When this is non-zero, a
|
|
|
|
// query/set is done within a block to improve cache locality.
|
|
|
|
// hash_func: customized hash function
|
|
|
|
explicit DynamicBloom(uint32_t total_bits, uint32_t cl_per_block = 0,
|
2014-05-04 17:37:09 +02:00
|
|
|
uint32_t num_probes = 6,
|
|
|
|
uint32_t (*hash_func)(const Slice& key) = nullptr);
|
2013-11-27 23:27:02 +01:00
|
|
|
|
2014-05-04 17:37:09 +02:00
|
|
|
~DynamicBloom() {
|
|
|
|
delete[] raw_;
|
|
|
|
}
|
2013-11-27 23:27:02 +01:00
|
|
|
|
2014-01-17 21:22:39 +01:00
|
|
|
// Assuming single threaded access to this function.
|
|
|
|
void Add(const Slice& key);
|
2013-11-27 23:27:02 +01:00
|
|
|
|
2014-01-17 21:22:39 +01:00
|
|
|
// Assuming single threaded access to this function.
|
2013-12-20 18:35:24 +01:00
|
|
|
void AddHash(uint32_t hash);
|
|
|
|
|
2014-01-17 21:22:39 +01:00
|
|
|
// Multithreaded access to this function is OK
|
2013-11-27 23:27:02 +01:00
|
|
|
bool MayContain(const Slice& key);
|
|
|
|
|
2014-01-17 21:22:39 +01:00
|
|
|
// Multithreaded access to this function is OK
|
2013-12-20 18:35:24 +01:00
|
|
|
bool MayContainHash(uint32_t hash);
|
2013-11-27 23:27:02 +01:00
|
|
|
|
|
|
|
private:
|
2014-03-28 17:21:20 +01:00
|
|
|
const bool kBlocked;
|
|
|
|
const uint32_t kBitsPerBlock;
|
2014-01-15 06:30:13 +01:00
|
|
|
const uint32_t kTotalBits;
|
2014-03-28 17:21:20 +01:00
|
|
|
const uint32_t kNumBlocks;
|
2014-01-15 06:30:13 +01:00
|
|
|
const uint32_t kNumProbes;
|
2014-03-28 17:21:20 +01:00
|
|
|
|
|
|
|
uint32_t (*hash_func_)(const Slice& key);
|
|
|
|
unsigned char* data_;
|
|
|
|
unsigned char* raw_;
|
2013-11-27 23:27:02 +01:00
|
|
|
};
|
|
|
|
|
2014-01-17 21:22:39 +01:00
|
|
|
inline void DynamicBloom::Add(const Slice& key) { AddHash(hash_func_(key)); }
|
|
|
|
|
2014-01-15 06:30:13 +01:00
|
|
|
inline bool DynamicBloom::MayContain(const Slice& key) {
|
|
|
|
return (MayContainHash(hash_func_(key)));
|
|
|
|
}
|
|
|
|
|
|
|
|
inline bool DynamicBloom::MayContainHash(uint32_t h) {
|
|
|
|
const uint32_t delta = (h >> 17) | (h << 15); // Rotate right 17 bits
|
2014-03-28 17:21:20 +01:00
|
|
|
if (kBlocked) {
|
|
|
|
uint32_t b = ((h >> 11 | (h << 21)) % kNumBlocks) * kBitsPerBlock;
|
|
|
|
for (uint32_t i = 0; i < kNumProbes; ++i) {
|
|
|
|
const uint32_t bitpos = b + h % kBitsPerBlock;
|
|
|
|
if (((data_[bitpos / 8]) & (1 << (bitpos % 8))) == 0) {
|
|
|
|
return false;
|
|
|
|
}
|
|
|
|
h += delta;
|
|
|
|
}
|
|
|
|
} else {
|
|
|
|
for (uint32_t i = 0; i < kNumProbes; ++i) {
|
|
|
|
const uint32_t bitpos = h % kTotalBits;
|
|
|
|
if (((data_[bitpos / 8]) & (1 << (bitpos % 8))) == 0) {
|
|
|
|
return false;
|
|
|
|
}
|
|
|
|
h += delta;
|
2014-01-15 06:30:13 +01:00
|
|
|
}
|
|
|
|
}
|
|
|
|
return true;
|
2013-11-27 23:27:02 +01:00
|
|
|
}
|
2014-01-15 06:30:13 +01:00
|
|
|
|
|
|
|
inline void DynamicBloom::AddHash(uint32_t h) {
|
|
|
|
const uint32_t delta = (h >> 17) | (h << 15); // Rotate right 17 bits
|
2014-03-28 17:21:20 +01:00
|
|
|
if (kBlocked) {
|
|
|
|
uint32_t b = ((h >> 11 | (h << 21)) % kNumBlocks) * kBitsPerBlock;
|
|
|
|
for (uint32_t i = 0; i < kNumProbes; ++i) {
|
|
|
|
const uint32_t bitpos = b + h % kBitsPerBlock;
|
|
|
|
data_[bitpos / 8] |= (1 << (bitpos % 8));
|
|
|
|
h += delta;
|
|
|
|
}
|
|
|
|
} else {
|
|
|
|
for (uint32_t i = 0; i < kNumProbes; ++i) {
|
|
|
|
const uint32_t bitpos = h % kTotalBits;
|
|
|
|
data_[bitpos / 8] |= (1 << (bitpos % 8));
|
|
|
|
h += delta;
|
|
|
|
}
|
2014-01-15 06:30:13 +01:00
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
} // rocksdb
|