// 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.

#ifndef STORAGE_LEVELDB_TABLE_BLOCK_BUILDER_H_

#define STORAGE_LEVELDB_TABLE_BLOCK_BUILDER_H_

#include <cstdint>

#include <vector>

#include "leveldb/slice.h"

namespace leveldb {

struct Options;

class BlockBuilder {

 public:

  explicit BlockBuilder(const Options* options);

  BlockBuilder(const BlockBuilder&) = delete;

  BlockBuilder& operator=(const BlockBuilder&) = delete;

  // 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);

  // 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.

  size_t CurrentSizeEstimate() const;

  // Return true iff no entries have been added since the last Reset()

  bool empty() const { return buffer_.empty(); }

 private:

  const Options* options_;

  std::string buffer_;              // Destination buffer

  std::vector<uint32_t> restarts_;  // Restart points

  int counter_;                     // Number of entries emitted since restart

  bool finished_;                   // Has Finish() been called?

  std::string last_key_;

};

}  // namespace leveldb

#endif  // STORAGE_LEVELDB_TABLE_BLOCK_BUILDER_H_