1 /*
2 * Copyright 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 // clang-format off
18 #include "../Macros.h"
19 // clang-format on
20
21 #include "SlopController.h"
22
23 namespace {
signOf(float value)24 int signOf(float value) {
25 if (value == 0) return 0;
26 if (value > 0) return 1;
27 return -1;
28 }
29 } // namespace
30
31 namespace android {
32
SlopController(float slopThreshold,nsecs_t slopDurationNanos)33 SlopController::SlopController(float slopThreshold, nsecs_t slopDurationNanos)
34 : mSlopThreshold(slopThreshold), mSlopDurationNanos(slopDurationNanos) {}
35
consumeEvent(nsecs_t eventTimeNanos,float value)36 float SlopController::consumeEvent(nsecs_t eventTimeNanos, float value) {
37 if (mSlopDurationNanos == 0) {
38 return value;
39 }
40
41 if (shouldResetSlopTracking(eventTimeNanos, value)) {
42 mCumulativeValue = 0;
43 mHasSlopBeenMet = false;
44 }
45
46 mLastEventTimeNanos = eventTimeNanos;
47
48 if (mHasSlopBeenMet) {
49 // Since slop has already been met, we know that all of the current value would pass the
50 // slop threshold. So return that, without any further processing.
51 return value;
52 }
53
54 mCumulativeValue += value;
55
56 if (abs(mCumulativeValue) >= mSlopThreshold) {
57 ALOGD("SlopController: did not drop event with value .%3f", value);
58 mHasSlopBeenMet = true;
59 // Return the amount of value that exceeds the slop.
60 return signOf(value) * (abs(mCumulativeValue) - mSlopThreshold);
61 }
62
63 ALOGD("SlopController: dropping event with value .%3f", value);
64 return 0;
65 }
66
shouldResetSlopTracking(nsecs_t eventTimeNanos,float value) const67 bool SlopController::shouldResetSlopTracking(nsecs_t eventTimeNanos, float value) const {
68 const nsecs_t ageNanos = eventTimeNanos - mLastEventTimeNanos;
69 if (ageNanos >= mSlopDurationNanos) {
70 return true;
71 }
72 if (value == 0) {
73 return false;
74 }
75 if (signOf(mCumulativeValue) != signOf(value)) {
76 return true;
77 }
78 return false;
79 }
80
81 } // namespace android
82