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A library jar that provides APIs for Applications written for the Google Android Platform.

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/*
 * Copyright (C) 2014 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;

import android.annotation.SystemApi;
import android.os.Parcel;
import android.os.Parcelable;

import java.util.Arrays;
import java.util.Objects;

/**
 * A curve defining the network score over a range of RSSI values.
 *
 * 

For each RSSI bucket, the score may be any byte. Scores have no absolute meaning and are only * considered relative to other scores assigned by the same scorer. Networks with no score are all * considered equivalent and ranked below any network with a score. * *

For example, consider a curve starting at -110 dBm with a bucket width of 10 and the * following buckets: {@code [-20, -10, 0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120]}. * This represents a linear curve between -110 dBm and 30 dBm. It scores progressively higher at * stronger signal strengths. * *

A network can be assigned a fixed score independent of RSSI by setting * {@link #rssiBuckets} to a one-byte array whose element is the fixed score. {@link #start} * should be set to the lowest RSSI value at which this fixed score should apply, and * {@link #bucketWidth} should be set such that {@code start + bucketWidth} is equal to the * highest RSSI value at which this fixed score should apply. * *

Note that RSSI values below -110 dBm or above 30 dBm are unlikely to cause any difference * in connectivity behavior from those endpoints. That is, the connectivity framework will treat * a network with a -120 dBm signal exactly as it would treat one with a -110 dBm signal. * Therefore, graphs which specify scores outside this range may be truncated to this range by * the system. * * @see ScoredNetwork * @hide */ @SystemApi public class RssiCurve implements Parcelable { /** The starting dBm of the curve. */ public final int start; /** The width of each RSSI bucket, in dBm. */ public final int bucketWidth; /** The score for each RSSI bucket. */ public final byte[] rssiBuckets; /** * Construct a new {@link RssiCurve}. * * @param start the starting dBm of the curve. * @param bucketWidth the width of each RSSI bucket, in dBm. * @param rssiBuckets the score for each RSSI bucket. */ public RssiCurve(int start, int bucketWidth, byte[] rssiBuckets) { this.start = start; this.bucketWidth = bucketWidth; if (rssiBuckets == null || rssiBuckets.length == 0) { throw new IllegalArgumentException("rssiBuckets must be at least one element large."); } this.rssiBuckets = rssiBuckets; } private RssiCurve(Parcel in) { start = in.readInt(); bucketWidth = in.readInt(); int bucketCount = in.readInt(); rssiBuckets = new byte[bucketCount]; in.readByteArray(rssiBuckets); } @Override public int describeContents() { return 0; } @Override public void writeToParcel(Parcel out, int flags) { out.writeInt(start); out.writeInt(bucketWidth); out.writeInt(rssiBuckets.length); out.writeByteArray(rssiBuckets); } /** * Lookup the score for a given RSSI value. * * @param rssi The RSSI to lookup. If the RSSI falls below the start of the curve, the score at * the start of the curve will be returned. If it falls after the end of the curve, the * score at the end of the curve will be returned. * @return the score for the given RSSI. */ public byte lookupScore(int rssi) { int index = (rssi - start) / bucketWidth; // Snap the index to the closest bucket if it falls outside the curve. if (index < 0) { index = 0; } else if (index > rssiBuckets.length - 1) { index = rssiBuckets.length - 1; } return rssiBuckets[index]; } /** * Determine if two RSSI curves are defined in the same way. * *

Note that two curves can be equivalent but defined differently, e.g. if one bucket in one * curve is split into two buckets in another. For the purpose of this method, these curves are * not considered equal to each other. */ @Override public boolean equals(Object o) { if (this == o) return true; if (o == null || getClass() != o.getClass()) return false; RssiCurve rssiCurve = (RssiCurve) o; return start == rssiCurve.start && bucketWidth == rssiCurve.bucketWidth && Arrays.equals(rssiBuckets, rssiCurve.rssiBuckets); } @Override public int hashCode() { return Objects.hash(start, bucketWidth, rssiBuckets); } @Override public String toString() { StringBuilder sb = new StringBuilder(); sb.append("RssiCurve[start=") .append(start) .append(",bucketWidth=") .append(bucketWidth); sb.append(",buckets="); for (int i = 0; i < rssiBuckets.length; i++) { sb.append(rssiBuckets[i]); if (i < rssiBuckets.length - 1) { sb.append(","); } } sb.append("]"); return sb.toString(); } public static final Creator CREATOR = new Creator() { @Override public RssiCurve createFromParcel(Parcel in) { return new RssiCurve(in); } @Override public RssiCurve[] newArray(int size) { return new RssiCurve[size]; } }; }





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