1 /*
2 * Copyright (C) 2023 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 #include "src/trace_processor/db/null_overlay.h"
18
19 #include "src/trace_processor/db/storage_variants.h"
20
21 namespace perfetto {
22 namespace trace_processor {
23 namespace column {
24
Filter(FilterOp op,SqlValue sql_val,RowMap & rm) const25 void NullOverlay::Filter(FilterOp op, SqlValue sql_val, RowMap& rm) const {
26 if (op == FilterOp::kIsNull) {
27 rm.Intersect(RowMap(null_bv_->Not()));
28 return;
29 }
30 if (op == FilterOp::kIsNotNull) {
31 rm.Intersect(RowMap(null_bv_->Copy()));
32 return;
33 }
34
35 // Row map for filtered data, not the size of whole column.
36 RowMap filtered_data_rm(0, null_bv_->CountSetBits());
37 inner_->Filter(op, sql_val, filtered_data_rm);
38
39 // Select only rows that were not filtered out from null BitVector and
40 // intersect it with RowMap&.
41 rm.Intersect(RowMap(null_bv_->Copy()).SelectRows(filtered_data_rm));
42 }
43
StableSort(uint32_t * rows,uint32_t rows_size) const44 void NullOverlay::StableSort(uint32_t* rows, uint32_t rows_size) const {
45 uint32_t count_set_bits = null_bv_->CountSetBits();
46
47 std::vector<uint32_t> non_null_rows(count_set_bits);
48 std::vector<uint32_t> storage_to_rows(count_set_bits);
49
50 // Saving the map from `out` index to `storage` index gives us free `IsSet()`
51 // function, which would be very expensive otherwise.
52 for (auto it = null_bv_->IterateSetBits(); it; it.Next()) {
53 storage_to_rows[it.ordinal()] = it.index();
54 }
55
56 uint32_t cur_non_null_id = 0;
57 uint32_t cur_null_id = 0;
58
59 // Sort elements into null and non null.
60 for (uint32_t i = 0; i < rows_size; ++i) {
61 uint32_t row_idx = rows[i];
62 auto it = std::lower_bound(storage_to_rows.begin(), storage_to_rows.end(),
63 row_idx);
64
65 // This condition holds if the row is null.
66 if (it == storage_to_rows.end() || *it != row_idx) {
67 // We can override the out because we already used this data.
68 rows[cur_null_id++] = row_idx;
69 continue;
70 }
71
72 uint32_t non_null_idx =
73 static_cast<uint32_t>(std::distance(storage_to_rows.begin(), it));
74 non_null_rows[cur_non_null_id++] = non_null_idx;
75 }
76
77 // Sort storage and translate them into `rows` indices.
78 inner_->StableSort(non_null_rows.data(), count_set_bits);
79 uint32_t set_rows_offset = null_bv_->size() - count_set_bits;
80 for (uint32_t i = 0; i < count_set_bits; ++i) {
81 rows[set_rows_offset + i] = storage_to_rows[non_null_rows[i]];
82 }
83 }
84
85 } // namespace column
86 } // namespace trace_processor
87 } // namespace perfetto
88