android/net/RssiCurve.java - platform/prebuilts/fullsdk/sources/android-30 - Git at Google

 /*
  * 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.NonNull;
 import android.annotation.Nullable;
 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.
  *
  * <p>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
  * treated equivalently to a network with score {@link Byte#MIN_VALUE}, and will not be used.
  *
  * <p>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.
  *
  * <p>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.
  *
  * <p>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 {
     private static final int DEFAULT_ACTIVE_NETWORK_RSSI_BOOST = 25;

     /** 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;

     /**
      * The RSSI boost to give this network when active, in dBm.
      *
      * <p>When the system is connected to this network, it will pretend that the network has this
      * much higher of an RSSI. This is to avoid switching networks when another network has only a
      * slightly higher score.
      */
     public final int activeNetworkRssiBoost;

     /**
      * 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, bucketWidth, rssiBuckets, DEFAULT_ACTIVE_NETWORK_RSSI_BOOST);
     }

     /**
      * 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.
      * @param activeNetworkRssiBoost the RSSI boost to apply when this network is active, in dBm.
      */
     public RssiCurve(int start, int bucketWidth, byte[] rssiBuckets, int activeNetworkRssiBoost) {
         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;
         this.activeNetworkRssiBoost = activeNetworkRssiBoost;
     }

     private RssiCurve(Parcel in) {
         start = in.readInt();
         bucketWidth = in.readInt();
         int bucketCount = in.readInt();
         rssiBuckets = new byte[bucketCount];
         in.readByteArray(rssiBuckets);
         activeNetworkRssiBoost = in.readInt();
     }

     @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);
         out.writeInt(activeNetworkRssiBoost);
     }

     /**
      * 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) {
         return lookupScore(rssi, false /* isActiveNetwork */);
     }

     /**
      * 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.
      * @param isActiveNetwork Whether this network is currently active.
      * @return the score for the given RSSI.
      */
     public byte lookupScore(int rssi, boolean isActiveNetwork) {
         if (isActiveNetwork) {
             rssi += activeNetworkRssiBoost;
         }

         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.
      *
      * <p>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(@Nullable 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) &&
                 activeNetworkRssiBoost == rssiCurve.activeNetworkRssiBoost;
     }

     @Override
     public int hashCode() {
         return Objects.hash(start, bucketWidth, activeNetworkRssiBoost) ^ Arrays.hashCode(rssiBuckets);
     }

     @NonNull
     @Override
     public String toString() {
         StringBuilder sb = new StringBuilder();
         sb.append("RssiCurve[start=")
                 .append(start)
                 .append(",bucketWidth=")
                 .append(bucketWidth)
                 .append(",activeNetworkRssiBoost=")
                 .append(activeNetworkRssiBoost);

         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 @android.annotation.NonNull Creator<RssiCurve> CREATOR =
             new Creator<RssiCurve>() {
                 @Override
                 public RssiCurve createFromParcel(Parcel in) {
                     return new RssiCurve(in);
                 }

                 @Override
                 public RssiCurve[] newArray(int size) {
                     return new RssiCurve[size];
                 }
             };
 }
	/*
	* 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.NonNull;
	import android.annotation.Nullable;
	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.
	*
	* <p>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
	* treated equivalently to a network with score {@link Byte#MIN_VALUE}, and will not be used.
	*
	* <p>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.
	*
	* <p>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.
	*
	* <p>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 {
	private static final int DEFAULT_ACTIVE_NETWORK_RSSI_BOOST = 25;

	/** 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;

	/**
	* The RSSI boost to give this network when active, in dBm.
	*
	* <p>When the system is connected to this network, it will pretend that the network has this
	* much higher of an RSSI. This is to avoid switching networks when another network has only a
	* slightly higher score.
	*/
	public final int activeNetworkRssiBoost;

	/**
	* 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, bucketWidth, rssiBuckets, DEFAULT_ACTIVE_NETWORK_RSSI_BOOST);
	}

	/**
	* 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.
	* @param activeNetworkRssiBoost the RSSI boost to apply when this network is active, in dBm.
	*/
	public RssiCurve(int start, int bucketWidth, byte[] rssiBuckets, int activeNetworkRssiBoost) {
	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;
	this.activeNetworkRssiBoost = activeNetworkRssiBoost;
	}

	private RssiCurve(Parcel in) {
	start = in.readInt();
	bucketWidth = in.readInt();
	int bucketCount = in.readInt();
	rssiBuckets = new byte[bucketCount];
	in.readByteArray(rssiBuckets);
	activeNetworkRssiBoost = in.readInt();
	}

	@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);
	out.writeInt(activeNetworkRssiBoost);
	}

	/**
	* 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) {
	return lookupScore(rssi, false /* isActiveNetwork */);
	}

	/**
	* 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.
	* @param isActiveNetwork Whether this network is currently active.
	* @return the score for the given RSSI.
	*/
	public byte lookupScore(int rssi, boolean isActiveNetwork) {
	if (isActiveNetwork) {
	rssi += activeNetworkRssiBoost;
	}

	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.
	*
	* <p>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(@Nullable 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) &&
	activeNetworkRssiBoost == rssiCurve.activeNetworkRssiBoost;
	}

	@Override
	public int hashCode() {
	return Objects.hash(start, bucketWidth, activeNetworkRssiBoost) ^ Arrays.hashCode(rssiBuckets);
	}

	@NonNull
	@Override
	public String toString() {
	StringBuilder sb = new StringBuilder();
	sb.append("RssiCurve[start=")
	.append(start)
	.append(",bucketWidth=")
	.append(bucketWidth)
	.append(",activeNetworkRssiBoost=")
	.append(activeNetworkRssiBoost);

	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 @android.annotation.NonNull Creator<RssiCurve> CREATOR =
	new Creator<RssiCurve>() {
	@Override
	public RssiCurve createFromParcel(Parcel in) {
	return new RssiCurve(in);
	}

	@Override
	public RssiCurve[] newArray(int size) {
	return new RssiCurve[size];
	}
	};
	}