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