rocksdb/table/block_based/block_builder.h
Vijay Nadimpalli 50e470791d Organizing rocksdb/table directory by format
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/5373

Differential Revision: D15559425

Pulled By: vjnadimpalli

fbshipit-source-id: 5d6d6d615582bedd96a4b879bb25d429a6de8b55
2019-05-30 14:51:11 -07:00

76 lines
2.9 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.
#pragma once
#include <vector>
#include <stdint.h>
#include "rocksdb/slice.h"
#include "rocksdb/table.h"
#include "table/block_based/data_block_hash_index.h"
namespace rocksdb {
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();
// REQUIRES: Finish() has not been called since the last call to Reset().
// REQUIRES: key is larger than any previously added key
void Add(const Slice& key, const Slice& value,
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:
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_;
};
} // namespace rocksdb