/*
* Copyright (C) 2008 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package android.net.wifi;
import android.os.Parcelable;
import android.os.Parcel;
import java.util.ArrayList;
import java.util.Collection;
/**
* Describes the settings for batched wifi scans where the firmware performs many
* scans and stores the timestamped results without waking the main processor each time.
* This can give information over time with minimal battery impact.
* @hide pending review
*/
public class BatchedScanSettings implements Parcelable {
private static final String TAG = "BatchedScanSettings";
/** Used to indicate no preference for an int value */
public final static int UNSPECIFIED = Integer.MAX_VALUE;
// TODO - make MIN/mAX as standard for wifi batch capability requirement.
public final static int MIN_SCANS_PER_BATCH = 2;
public final static int MAX_SCANS_PER_BATCH = 20;
public final static int DEFAULT_SCANS_PER_BATCH = MAX_SCANS_PER_BATCH;
public final static int MIN_AP_PER_SCAN = 2;
public final static int MAX_AP_PER_SCAN = 16;
public final static int DEFAULT_AP_PER_SCAN = 16;
public final static int MIN_INTERVAL_SEC = 10;
public final static int MAX_INTERVAL_SEC = 500;
public final static int DEFAULT_INTERVAL_SEC = 30;
public final static int MIN_AP_FOR_DISTANCE = 0;
public final static int MAX_AP_FOR_DISTANCE = MAX_AP_PER_SCAN;
public final static int DEFAULT_AP_FOR_DISTANCE = 0;
public final static int MAX_WIFI_CHANNEL = 196;
/** The expected number of scans per batch. Note that the firmware may drop scans
* leading to fewer scans during the normal batch scan duration. This value need not
* be specified (may be set to {@link UNSPECIFIED}) by the application and we will try
* to scan as many times as the firmware can support. If another app requests fewer
* scans per batch we will attempt to honor that.
*/
public int maxScansPerBatch;
/** The maximum desired AP listed per scan. Fewer AP may be returned if that's all
* that the driver detected. If another application requests more AP per scan that
* will take precedence. The if more channels are detected than we request, the APs
* with the lowest signal strength will be dropped.
*/
public int maxApPerScan;
/** The channels used in the scan. If all channels should be used, {@code null} may be
* specified. If another application requests more channels or all channels, that
* will take precedence.
*/
public Collection<String> channelSet;
/** The time between the start of two sequential scans, in seconds. If another
* application requests more frequent scans, that will take precedence. If this
* value is less than the duration of a scan, the next scan should start immediately.
*/
public int scanIntervalSec;
/** The number of the best (strongest signal) APs for which the firmware will
* attempt to get distance information (RTT). Not all firmware supports this
* feature, so it may be ignored. If another application requests a greater
* number, that will take precedence.
*/
public int maxApForDistance;
public BatchedScanSettings() {
clear();
}
public void clear() {
maxScansPerBatch = UNSPECIFIED;
maxApPerScan = UNSPECIFIED;
channelSet = null;
scanIntervalSec = UNSPECIFIED;
maxApForDistance = UNSPECIFIED;
}
public BatchedScanSettings(BatchedScanSettings source) {
maxScansPerBatch = source.maxScansPerBatch;
maxApPerScan = source.maxApPerScan;
if (source.channelSet != null) {
channelSet = new ArrayList(source.channelSet);
}
scanIntervalSec = source.scanIntervalSec;
maxApForDistance = source.maxApForDistance;
}
private boolean channelSetIsValid() {
if (channelSet == null || channelSet.isEmpty()) return true;
for (String channel : channelSet) {
try {
int i = Integer.parseInt(channel);
if (i > 0 && i <= MAX_WIFI_CHANNEL) continue;
} catch (NumberFormatException e) {}
if (channel.equals("A") || channel.equals("B")) continue;
return false;
}
return true;
}
/** @hide */
public boolean isInvalid() {
if (maxScansPerBatch != UNSPECIFIED && (maxScansPerBatch < MIN_SCANS_PER_BATCH ||
maxScansPerBatch > MAX_SCANS_PER_BATCH)) return true;
if (maxApPerScan != UNSPECIFIED && (maxApPerScan < MIN_AP_PER_SCAN ||
maxApPerScan > MAX_AP_PER_SCAN)) return true;
if (channelSetIsValid() == false) return true;
if (scanIntervalSec != UNSPECIFIED && (scanIntervalSec < MIN_INTERVAL_SEC ||
scanIntervalSec > MAX_INTERVAL_SEC)) return true;
if (maxApForDistance != UNSPECIFIED && (maxApForDistance < MIN_AP_FOR_DISTANCE ||
maxApForDistance > MAX_AP_FOR_DISTANCE)) return true;
return false;
}
/** @hide */
public void constrain() {
if (scanIntervalSec == UNSPECIFIED) {
scanIntervalSec = DEFAULT_INTERVAL_SEC;
} else if (scanIntervalSec < MIN_INTERVAL_SEC) {
scanIntervalSec = MIN_INTERVAL_SEC;
} else if (scanIntervalSec > MAX_INTERVAL_SEC) {
scanIntervalSec = MAX_INTERVAL_SEC;
}
if (maxScansPerBatch == UNSPECIFIED) {
maxScansPerBatch = DEFAULT_SCANS_PER_BATCH;
} else if (maxScansPerBatch < MIN_SCANS_PER_BATCH) {
maxScansPerBatch = MIN_SCANS_PER_BATCH;
} else if (maxScansPerBatch > MAX_SCANS_PER_BATCH) {
maxScansPerBatch = MAX_SCANS_PER_BATCH;
}
if (maxApPerScan == UNSPECIFIED) {
maxApPerScan = DEFAULT_AP_PER_SCAN;
} else if (maxApPerScan < MIN_AP_PER_SCAN) {
maxApPerScan = MIN_AP_PER_SCAN;
} else if (maxApPerScan > MAX_AP_PER_SCAN) {
maxApPerScan = MAX_AP_PER_SCAN;
}
if (maxApForDistance == UNSPECIFIED) {
maxApForDistance = DEFAULT_AP_FOR_DISTANCE;
} else if (maxApForDistance < MIN_AP_FOR_DISTANCE) {
maxApForDistance = MIN_AP_FOR_DISTANCE;
} else if (maxApForDistance > MAX_AP_FOR_DISTANCE) {
maxApForDistance = MAX_AP_FOR_DISTANCE;
}
}
@Override
public boolean equals(Object obj) {
if (obj instanceof BatchedScanSettings == false) return false;
BatchedScanSettings o = (BatchedScanSettings)obj;
if (maxScansPerBatch != o.maxScansPerBatch ||
maxApPerScan != o.maxApPerScan ||
scanIntervalSec != o.scanIntervalSec ||
maxApForDistance != o.maxApForDistance) return false;
if (channelSet == null) {
return (o.channelSet == null);
}
return channelSet.equals(o.channelSet);
}
@Override
public int hashCode() {
return maxScansPerBatch +
(maxApPerScan * 3) +
(scanIntervalSec * 5) +
(maxApForDistance * 7) +
(channelSet.hashCode() * 11);
}
@Override
public String toString() {
StringBuffer sb = new StringBuffer();
String none = "<none>";
sb.append("BatchScanSettings [maxScansPerBatch: ").
append(maxScansPerBatch == UNSPECIFIED ? none : maxScansPerBatch).
append(", maxApPerScan: ").append(maxApPerScan == UNSPECIFIED? none : maxApPerScan).
append(", scanIntervalSec: ").
append(scanIntervalSec == UNSPECIFIED ? none : scanIntervalSec).
append(", maxApForDistance: ").
append(maxApForDistance == UNSPECIFIED ? none : maxApForDistance).
append(", channelSet: ");
if (channelSet == null) {
sb.append("ALL");
} else {
sb.append("<");
for (String channel : channelSet) {
sb.append(" " + channel);
}
sb.append(">");
}
sb.append("]");
return sb.toString();
}
/** Implement the Parcelable interface {@hide} */
public int describeContents() {
return 0;
}
/** Implement the Parcelable interface {@hide} */
public void writeToParcel(Parcel dest, int flags) {
dest.writeInt(maxScansPerBatch);
dest.writeInt(maxApPerScan);
dest.writeInt(scanIntervalSec);
dest.writeInt(maxApForDistance);
dest.writeInt(channelSet == null ? 0 : channelSet.size());
if (channelSet != null) {
for (String channel : channelSet) dest.writeString(channel);
}
}
/** Implement the Parcelable interface {@hide} */
public static final Creator<BatchedScanSettings> CREATOR =
new Creator<BatchedScanSettings>() {
public BatchedScanSettings createFromParcel(Parcel in) {
BatchedScanSettings settings = new BatchedScanSettings();
settings.maxScansPerBatch = in.readInt();
settings.maxApPerScan = in.readInt();
settings.scanIntervalSec = in.readInt();
settings.maxApForDistance = in.readInt();
int channelCount = in.readInt();
if (channelCount > 0) {
settings.channelSet = new ArrayList(channelCount);
while (channelCount-- > 0) {
settings.channelSet.add(in.readString());
}
}
return settings;
}
public BatchedScanSettings[] newArray(int size) {
return new BatchedScanSettings[size];
}
};
}
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