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       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                 :             : 
      14                 :             : namespace leveldb {
      15                 :             : 
      16                 :             : struct Options;
      17                 :             : 
      18                 :             : class 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   [ +  +  -  + ]:       18671 :   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_