text: // 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_TWO_LEVEL_ITERATOR_H_
  #define STORAGE_LEVELDB_TABLE_TWO_LEVEL_ITERATOR_H_
  
  #include "unikv/iterator.h"
  
  namespace leveldb {
  
  struct ReadOptions;
  
  // Return a new two level iterator.  A two-level iterator contains an
  // index iterator whose values point to a sequence of blocks where
  // each block is itself a sequence of key,value pairs.  The returned
  // two-level iterator yields the concatenation of all key/value pairs
  // in the sequence of blocks.  Takes ownership of "index_iter" and
  // will delete it when no longer needed.
  //
  // Uses a supplied function to convert an index_iter value into
  // an iterator over the contents of the corresponding block.
  extern Iterator* NewTwoLevelIterator(
      Iterator* index_iter,
      Iterator* (*block_function)(
          void* arg,
          const ReadOptions& options,
          const Slice& index_value),
      void* arg,
      const ReadOptions& options);
  
  }  // namespace leveldb
  
  #endif  // STORAGE_LEVELDB_TABLE_TWO_LEVEL_ITERATOR_H_
  