Inside Bitcoin

1// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file. See the AUTHORS file for names of contributors.
4
5#ifndef STORAGE_LEVELDB_TABLE_BLOCK_BUILDER_H_
6#define STORAGE_LEVELDB_TABLE_BLOCK_BUILDER_H_
7
8#include <stdint.h>
9
10#include <vector>
11
12#include "leveldb/slice.h"
13
14namespace leveldb {
15
16struct Options;
17
18class BlockBuilder {
19 public:
20  explicit BlockBuilder(const Options* options);
21
22  BlockBuilder(const BlockBuilder&) = delete;
23  BlockBuilder& operator=(const BlockBuilder&) = delete;
24
25  // Reset the contents as if the BlockBuilder was just constructed.
26  void Reset();
27
28  // REQUIRES: Finish() has not been called since the last call to Reset().
29  // REQUIRES: key is larger than any previously added key
30  void Add(const Slice& key, const Slice& value);
31
32  // Finish building the block and return a slice that refers to the
33  // block contents.  The returned slice will remain valid for the
34  // lifetime of this builder or until Reset() is called.
35  Slice Finish();
36
37  // Returns an estimate of the current (uncompressed) size of the block
38  // we are building.
39  size_t CurrentSizeEstimate() const;
40
41  // Return true iff no entries have been added since the last Reset()
42  bool empty() const { return buffer_.empty(); }
43
44 private:
45  const Options* options_;
46  std::string buffer_;              // Destination buffer
47  std::vector<uint32_t> restarts_;  // Restart points
48  int counter_;                     // Number of entries emitted since restart
49  bool finished_;                   // Has Finish() been called?
50  std::string last_key_;
51};
52
53}  // namespace leveldb
54
55#endif  // STORAGE_LEVELDB_TABLE_BLOCK_BUILDER_H_
56