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1 /*
2  * Copyright (C) 2018 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #ifndef SRC_TRACE_PROCESSOR_ROW_ITERATORS_H_
18 #define SRC_TRACE_PROCESSOR_ROW_ITERATORS_H_
19 
20 #include <stdint.h>
21 #include <vector>
22 
23 namespace perfetto {
24 namespace trace_processor {
25 
26 // Implements a strategy of yielding indices into a storage system to fulfil
27 // a query.
28 class RowIterator {
29  public:
30   virtual ~RowIterator();
31 
32   virtual void NextRow() = 0;
33   virtual uint32_t Row() = 0;
34   virtual bool IsEnd() = 0;
35 };
36 
37 // A row iterator which iterates through a range of indicies in either ascending
38 // or descending order and optionally skips rows depending on a bitvector.
39 class RangeRowIterator : public RowIterator {
40  public:
41   RangeRowIterator(uint32_t start_row, uint32_t end_row, bool desc);
42   RangeRowIterator(uint32_t start_row, bool desc, std::vector<bool> row_filter);
43 
44   void NextRow() override;
45   bool IsEnd() override;
46   uint32_t Row() override;
47 
48   uint32_t RowCount() const;
49 
50  private:
51   uint32_t start_row_ = 0;
52   uint32_t end_row_ = 0;
53   bool desc_ = false;
54   std::vector<bool> row_filter_;
55 
56   // In non-desc mode, this is an offset from start_row_ while in desc mode,
57   // this is an offset from end_row_.
58   uint32_t offset_ = 0;
59 };
60 
61 // A row iterator which yields row indices from a provided vector.
62 class VectorRowIterator : public RowIterator {
63  public:
64   explicit VectorRowIterator(std::vector<uint32_t> row_indices);
65   ~VectorRowIterator() override;
66 
67   void NextRow() override;
68   bool IsEnd() override;
69   uint32_t Row() override;
70 
71  private:
72   std::vector<uint32_t> row_indices_;
73   uint32_t offset_ = 0;
74 };
75 
76 }  // namespace trace_processor
77 }  // namespace perfetto
78 
79 #endif  // SRC_TRACE_PROCESSOR_ROW_ITERATORS_H_
80