ScanScheduleUtil.java revision 4e54617758f86acef751bc8588257a58ed985b0f 
1/*
2 * Copyright (C) 2015 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
17package com.android.server.wifi.scanner;
18
19import android.annotation.Nullable;
20import android.net.wifi.ScanResult;
21import android.net.wifi.WifiScanner.ScanData;
22import android.net.wifi.WifiScanner.ScanSettings;
23
24import com.android.server.wifi.WifiNative;
25
26import java.util.ArrayList;
27import java.util.List;
28
29/**
30 * A class with utilities for dealing with scan schedules.
31 */
32public class ScanScheduleUtil {
33
34    /**
35     * Compares two ChannelSettings for equality.
36     */
37    public static boolean channelEquals(@Nullable WifiNative.ChannelSettings channel1,
38                                         @Nullable WifiNative.ChannelSettings channel2) {
39        if (channel1 == null || channel2 == null) return false;
40        if (channel1 == channel2) return true;
41
42        if (channel1.frequency != channel2.frequency) return false;
43        if (channel1.dwell_time_ms != channel2.dwell_time_ms) return false;
44        return channel1.passive == channel2.passive;
45    }
46
47    /**
48     * Compares two BucketSettings for equality.
49     */
50    public static boolean bucketEquals(@Nullable WifiNative.BucketSettings bucket1,
51                                        @Nullable WifiNative.BucketSettings bucket2) {
52        if (bucket1 == null || bucket2 == null) return false;
53        if (bucket1 == bucket2) return true;
54
55        if (bucket1.bucket != bucket2.bucket) return false;
56        if (bucket1.band != bucket2.band) return false;
57        if (bucket1.period_ms != bucket2.period_ms) return false;
58        if (bucket1.report_events != bucket2.report_events) return false;
59        if (bucket1.num_channels != bucket2.num_channels) return false;
60        for (int c = 0; c < bucket1.num_channels; c++) {
61            if (!channelEquals(bucket1.channels[c], bucket2.channels[c])) {
62                return false;
63            }
64        }
65
66        return true;
67    }
68
69    /**
70     * Compares two ScanSettings for equality.
71     */
72    public static boolean scheduleEquals(@Nullable WifiNative.ScanSettings schedule1,
73                                         @Nullable WifiNative.ScanSettings schedule2) {
74        if (schedule1 == null || schedule2 == null) return false;
75        if (schedule1 == schedule2) return true;
76
77        if (schedule1.base_period_ms != schedule2.base_period_ms) return false;
78        if (schedule1.max_ap_per_scan != schedule2.max_ap_per_scan) return false;
79        if (schedule1.report_threshold_percent != schedule2.report_threshold_percent) return false;
80        if (schedule1.report_threshold_num_scans != schedule2.report_threshold_num_scans) {
81            return false;
82        }
83        if (schedule1.num_buckets != schedule2.num_buckets) return false;
84        for (int b = 0; b < schedule1.num_buckets; b++) {
85            if (!bucketEquals(schedule1.buckets[b], schedule2.buckets[b])) {
86                return false;
87            }
88        }
89
90        return true;
91    }
92
93    /**
94     * Returns true if the given scan result should be reported to a listener with the given
95     * settings.
96     */
97    public static boolean shouldReportFullScanResultForSettings(ChannelHelper channelHelper,
98            ScanResult result, ScanSettings settings) {
99        return channelHelper.settingsContainChannel(settings, result.frequency);
100    }
101
102    /**
103     * Returns a filtered version of the scan results from the chip that represents only the data
104     * requested in the settings. Will return null if the result should not be reported.
105     */
106    public static ScanData[] filterResultsForSettings(ChannelHelper channelHelper,
107            ScanData[] scanDatas, ScanSettings settings) {
108        List<ScanData> filteredScanDatas = new ArrayList<>(scanDatas.length);
109        List<ScanResult> filteredResults = new ArrayList<>();
110        for (ScanData scanData : scanDatas) {
111            filteredResults.clear();
112            for (ScanResult scanResult : scanData.getResults()) {
113                if (channelHelper.settingsContainChannel(settings, scanResult.frequency)) {
114                    filteredResults.add(scanResult);
115                }
116                if (settings.numBssidsPerScan > 0
117                        && filteredResults.size() >= settings.numBssidsPerScan) {
118                    break;
119                }
120            }
121            if (filteredResults.size() == scanData.getResults().length) {
122                filteredScanDatas.add(scanData);
123            } else if (filteredResults.size() > 0) {
124                filteredScanDatas.add(new ScanData(scanData.getId(),
125                                scanData.getFlags(),
126                                filteredResults.toArray(
127                                        new ScanResult[filteredResults.size()])));
128            }
129        }
130        if (filteredScanDatas.size() == 0) {
131            return null;
132        } else {
133            return filteredScanDatas.toArray(new ScanData[filteredScanDatas.size()]);
134        }
135    }
136}
137