mirror of https://github.com/facebook/rocksdb.git
60 lines
1.8 KiB
C++
60 lines
1.8 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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//
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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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#include "data_block_footer.h"
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#include "rocksdb/table.h"
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namespace rocksdb {
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const int kDataBlockIndexTypeBitShift = 31;
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// 0x7FFFFFFF
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const uint32_t kMaxNumRestarts = (1u << kDataBlockIndexTypeBitShift) - 1u;
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// 0x7FFFFFFF
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const uint32_t kNumRestartsMask = (1u << kDataBlockIndexTypeBitShift) - 1u;
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uint32_t PackIndexTypeAndNumRestarts(
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BlockBasedTableOptions::DataBlockIndexType index_type,
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uint32_t num_restarts) {
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if (num_restarts > kMaxNumRestarts) {
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assert(0); // mute travis "unused" warning
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}
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uint32_t block_footer = num_restarts;
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if (index_type == BlockBasedTableOptions::kDataBlockBinaryAndHash) {
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block_footer |= 1u << kDataBlockIndexTypeBitShift;
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} else if (index_type != BlockBasedTableOptions::kDataBlockBinarySearch) {
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assert(0);
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}
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return block_footer;
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}
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void UnPackIndexTypeAndNumRestarts(
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uint32_t block_footer,
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BlockBasedTableOptions::DataBlockIndexType* index_type,
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uint32_t* num_restarts) {
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if (index_type) {
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if (block_footer & 1u << kDataBlockIndexTypeBitShift) {
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*index_type = BlockBasedTableOptions::kDataBlockBinaryAndHash;
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} else {
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*index_type = BlockBasedTableOptions::kDataBlockBinarySearch;
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}
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}
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if (num_restarts) {
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*num_restarts = block_footer & kNumRestartsMask;
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assert(*num_restarts <= kMaxNumRestarts);
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}
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}
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} // namespace rocksdb
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