1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
|
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
#include <algorithm>
#include <string>
#include "utilities/merge_operators/bytesxor.h"
namespace ROCKSDB_NAMESPACE {
std::shared_ptr<MergeOperator> MergeOperators::CreateBytesXOROperator() {
return std::make_shared<BytesXOROperator>();
}
bool BytesXOROperator::Merge(const Slice& /*key*/,
const Slice* existing_value,
const Slice& value,
std::string* new_value,
Logger* /*logger*/) const {
XOR(existing_value, value, new_value);
return true;
}
void BytesXOROperator::XOR(const Slice* existing_value,
const Slice& value, std::string* new_value) const {
if (!existing_value) {
new_value->clear();
new_value->assign(value.data(), value.size());
return;
}
size_t min_size = std::min(existing_value->size(), value.size());
size_t max_size = std::max(existing_value->size(), value.size());
new_value->clear();
new_value->reserve(max_size);
const char* existing_value_data = existing_value->data();
const char* value_data = value.data();
for (size_t i = 0; i < min_size; i++) {
new_value->push_back(existing_value_data[i] ^ value_data[i]);
}
if (existing_value->size() == max_size) {
for (size_t i = min_size; i < max_size; i++) {
new_value->push_back(existing_value_data[i]);
}
} else {
assert(value.size() == max_size);
for (size_t i = min_size; i < max_size; i++) {
new_value->push_back(value_data[i]);
}
}
}
} // namespace ROCKSDB_NAMESPACE
|
