1/* Copyright 2015 The TensorFlow Authors. All Rights Reserved.
2
3Licensed under the Apache License, Version 2.0 (the "License");
4you may not use this file except in compliance with the License.
5You may obtain a copy of the License at
6
7    http://www.apache.org/licenses/LICENSE-2.0
8
9Unless required by applicable law or agreed to in writing, software
10distributed under the License is distributed on an "AS IS" BASIS,
11WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12See the License for the specific language governing permissions and
13limitations under the License.
14==============================================================================*/
15
16// A class to manage slices of a tensor. You can "register" set of slices for a
17// tensor and then "query" if we have data for a given slice.
18
19// TODO(yangke): consider moving it to a more private place so that we don't
20// need to expose the API.
21
22#ifndef TENSORFLOW_UTIL_TENSOR_SLICE_SET_H_
23#define TENSORFLOW_UTIL_TENSOR_SLICE_SET_H_
24
25#include <string>  // for string
26#include <unordered_map>
27#include <vector>
28
29#include "tensorflow/core/framework/tensor_shape.h"
30#include "tensorflow/core/framework/tensor_slice.h"
31#include "tensorflow/core/framework/types.h"
32#include "tensorflow/core/lib/core/status.h"       // for Status
33#include "tensorflow/core/lib/core/stringpiece.h"  // for StringPiece
34#include "tensorflow/core/platform/types.h"        // for int64
35
36namespace tensorflow {
37
38namespace checkpoint {
39
40class TensorSliceSet {
41 public:
42  TensorSliceSet(const TensorShape& shape, DataType type);
43  virtual ~TensorSliceSet();
44
45  const TensorShape& shape() const { return shape_; }
46  const DataType type() const { return type_; }
47
48  // Register a new slice for the tensor. The "tag" is an arbitrary string
49  // associated with the slice (in one application it denotes the name of the
50  // file that contains the slice); the "data" points to the data of the tensor
51  // slice (it can be a nullptr).
52  // We don't take the ownership of "data" and the caller needs to make sure
53  // the data is always available during the life time of the tensor slice set
54  // if it is not nullptr.
55  Status Register(const TensorSlice& slice, const string& tag,
56                  const float* data);
57
58  // Query about a new slice: checks if we have data for "slice" and if we have
59  // the data and "data" is not nullptr, fill "data" with the slice data. The
60  // caller needs to make sure "data" point to a large enough buffer.
61  // TODO(yangke): avoid unnecessary copying by using a core::RefCounted
62  // pointer.
63  bool Query(const TensorSlice& slice, float* data) const;
64
65  // Alternative way of querying about a new slice: instead of copying the
66  // data, it returns a list of meta data about the stored slices that will
67  // supply data for the slice.
68  bool QueryMeta(
69      const TensorSlice& slice,
70      std::vector<std::pair<tensorflow::TensorSlice, string>>* results) const;
71
72  struct SliceInfo {
73    TensorSlice slice;
74    const string tag;
75    const float* data;
76    int64 num_floats;
77  };
78
79  // Returns the map from slice string to SliceInfo.
80  const std::unordered_map<string, SliceInfo>& Slices() const {
81    return slices_;
82  }
83
84 private:
85  const TensorShape shape_;
86  const DataType type_;
87  // We maintain a mapping from the slice string to the slice information.
88  std::unordered_map<string, SliceInfo> slices_;
89
90  // Minimal slice which contains all presented slices. Used for speeding up
91  // overlap check when slices are being added consequently.
92  TensorSlice slices_hull_;
93};
94
95// Registers "slice" in the TensorSliceSet stored in "tensor_slices", under key
96// "name".  Other arguments are used for validations.  Does not modify the map
97// or its values on non-OK.
98// REQUIRES: tensor_slices != nullptr
99Status RegisterTensorSlice(
100    const string& name, const TensorShape& shape, DataType type,
101    const string& tag, const TensorSlice& slice,
102    std::unordered_map<string, TensorSliceSet*>* tensor_slices);
103
104}  // namespace checkpoint
105
106}  // namespace tensorflow
107
108#endif  // TENSORFLOW_UTIL_TENSOR_SLICE_SET_H_
109