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-rw-r--r--src/rocksdb/table/block_based/data_block_footer.cc59
1 files changed, 59 insertions, 0 deletions
diff --git a/src/rocksdb/table/block_based/data_block_footer.cc b/src/rocksdb/table/block_based/data_block_footer.cc
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+// 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_NAMESPACE {
+
+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_NAMESPACE