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diff --git a/src/rocksdb/table/block_based/block_builder.h b/src/rocksdb/table/block_based/block_builder.h
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+++ b/src/rocksdb/table/block_based/block_builder.h
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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.
+
+#pragma once
+#include <stdint.h>
+
+#include <vector>
+
+#include "rocksdb/slice.h"
+#include "rocksdb/table.h"
+#include "table/block_based/data_block_hash_index.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+class BlockBuilder {
+ public:
+  BlockBuilder(const BlockBuilder&) = delete;
+  void operator=(const BlockBuilder&) = delete;
+
+  explicit BlockBuilder(int block_restart_interval,
+                        bool use_delta_encoding = true,
+                        bool use_value_delta_encoding = false,
+                        BlockBasedTableOptions::DataBlockIndexType index_type =
+                            BlockBasedTableOptions::kDataBlockBinarySearch,
+                        double data_block_hash_table_util_ratio = 0.75);
+
+  // Reset the contents as if the BlockBuilder was just constructed.
+  void Reset();
+
+  // Swap the contents in BlockBuilder with buffer, then reset the BlockBuilder.
+  void SwapAndReset(std::string& buffer);
+
+  // REQUIRES: Finish() has not been called since the last call to Reset().
+  // REQUIRES: key is larger than any previously added key
+  // DO NOT mix with AddWithLastKey() between Resets. For efficiency, use
+  // AddWithLastKey() in contexts where previous added key is already known
+  // and delta encoding might be used.
+  void Add(const Slice& key, const Slice& value,
+           const Slice* const delta_value = nullptr);
+
+  // A faster version of Add() if the previous key is already known for all
+  // Add()s.
+  // REQUIRES: Finish() has not been called since the last call to Reset().
+  // REQUIRES: key is larger than any previously added key
+  // REQUIRES: if AddWithLastKey has been called since last Reset(), last_key
+  // is the key from most recent AddWithLastKey. (For convenience, last_key
+  // is ignored on first call after creation or Reset().)
+  // DO NOT mix with Add() between Resets.
+  void AddWithLastKey(const Slice& key, const Slice& value,
+                      const Slice& last_key,
+                      const Slice* const delta_value = nullptr);
+
+  // Finish building the block and return a slice that refers to the
+  // block contents.  The returned slice will remain valid for the
+  // lifetime of this builder or until Reset() is called.
+  Slice Finish();
+
+  // Returns an estimate of the current (uncompressed) size of the block
+  // we are building.
+  inline size_t CurrentSizeEstimate() const {
+    return estimate_ + (data_block_hash_index_builder_.Valid()
+                            ? data_block_hash_index_builder_.EstimateSize()
+                            : 0);
+  }
+
+  // Returns an estimated block size after appending key and value.
+  size_t EstimateSizeAfterKV(const Slice& key, const Slice& value) const;
+
+  // Return true iff no entries have been added since the last Reset()
+  bool empty() const { return buffer_.empty(); }
+
+ private:
+  inline void AddWithLastKeyImpl(const Slice& key, const Slice& value,
+                                 const Slice& last_key,
+                                 const Slice* const delta_value,
+                                 size_t buffer_size);
+
+  const int block_restart_interval_;
+  // TODO(myabandeh): put it into a separate IndexBlockBuilder
+  const bool use_delta_encoding_;
+  // Refer to BlockIter::DecodeCurrentValue for format of delta encoded values
+  const bool use_value_delta_encoding_;
+
+  std::string buffer_;              // Destination buffer
+  std::vector<uint32_t> restarts_;  // Restart points
+  size_t estimate_;
+  int counter_;    // Number of entries emitted since restart
+  bool finished_;  // Has Finish() been called?
+  std::string last_key_;
+  DataBlockHashIndexBuilder data_block_hash_index_builder_;
+#ifndef NDEBUG
+  bool add_with_last_key_called_ = false;
+#endif
+};
+
+}  // namespace ROCKSDB_NAMESPACE