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_TWO_LEVEL_ITERATOR_H_
 6  #define STORAGE_LEVELDB_TABLE_TWO_LEVEL_ITERATOR_H_
 7  
 8  #include "leveldb/iterator.h"
 9  
10  namespace leveldb {
11  
12  struct ReadOptions;
13  
14  // Return a new two level iterator.  A two-level iterator contains an
15  // index iterator whose values point to a sequence of blocks where
16  // each block is itself a sequence of key,value pairs.  The returned
17  // two-level iterator yields the concatenation of all key/value pairs
18  // in the sequence of blocks.  Takes ownership of "index_iter" and
19  // will delete it when no longer needed.
20  //
21  // Uses a supplied function to convert an index_iter value into
22  // an iterator over the contents of the corresponding block.
23  Iterator* NewTwoLevelIterator(
24      Iterator* index_iter,
25      Iterator* (*block_function)(void* arg, const ReadOptions& options,
26                                  const Slice& index_value),
27      void* arg, const ReadOptions& options);
28  
29  }  // namespace leveldb
30  
31  #endif  // STORAGE_LEVELDB_TABLE_TWO_LEVEL_ITERATOR_H_