mirror of https://github.com/facebook/rocksdb.git
58 lines
1.7 KiB
C++
58 lines
1.7 KiB
C++
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
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// This source code is licensed under both the GPLv2 (found in the
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// COPYING file in the root directory) and Apache 2.0 License
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// (found in the LICENSE.Apache file in the root directory).
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#include "utilities/merge_operators/bytesxor.h"
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#include <algorithm>
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#include <string>
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namespace ROCKSDB_NAMESPACE {
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std::shared_ptr<MergeOperator> MergeOperators::CreateBytesXOROperator() {
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return std::make_shared<BytesXOROperator>();
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}
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bool BytesXOROperator::Merge(const Slice& /*key*/, const Slice* existing_value,
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const Slice& value, std::string* new_value,
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Logger* /*logger*/) const {
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XOR(existing_value, value, new_value);
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return true;
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}
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void BytesXOROperator::XOR(const Slice* existing_value, const Slice& value,
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std::string* new_value) const {
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if (!existing_value) {
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new_value->clear();
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new_value->assign(value.data(), value.size());
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return;
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}
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size_t min_size = std::min(existing_value->size(), value.size());
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size_t max_size = std::max(existing_value->size(), value.size());
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new_value->clear();
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new_value->reserve(max_size);
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const char* existing_value_data = existing_value->data();
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const char* value_data = value.data();
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for (size_t i = 0; i < min_size; i++) {
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new_value->push_back(existing_value_data[i] ^ value_data[i]);
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}
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if (existing_value->size() == max_size) {
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for (size_t i = min_size; i < max_size; i++) {
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new_value->push_back(existing_value_data[i]);
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}
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} else {
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assert(value.size() == max_size);
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for (size_t i = min_size; i < max_size; i++) {
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new_value->push_back(value_data[i]);
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}
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}
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}
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} // namespace ROCKSDB_NAMESPACE
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