/* Copyright 2015 The TensorFlow Authors. All Rights Reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
==============================================================================*/

#ifndef TENSORFLOW_LIB_IO_TWO_LEVEL_ITERATOR_H_
#define TENSORFLOW_LIB_IO_TWO_LEVEL_ITERATOR_H_

#include "tensorflow/core/lib/io/iterator.h"

namespace tensorflow {
namespace table {

// 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 StringPiece& index_value),
    void* arg);

}  // namespace table
}  // namespace tensorflow

#endif  // TENSORFLOW_LIB_IO_TWO_LEVEL_ITERATOR_H_