Merge "Let scorers fine-tune scoring heuristics." into lmp-mr1-dev
diff --git a/core/java/android/net/RssiCurve.java b/core/java/android/net/RssiCurve.java
index f653f37..8ebe9e8 100644
--- a/core/java/android/net/RssiCurve.java
+++ b/core/java/android/net/RssiCurve.java
@@ -27,8 +27,8 @@
* 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 all
- * considered equivalent and ranked below any network with a score.
+ * 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]}.
@@ -52,6 +52,7 @@
*/
@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;
@@ -63,6 +64,15 @@
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.
@@ -70,12 +80,25 @@
* @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) {
@@ -84,6 +107,7 @@
int bucketCount = in.readInt();
rssiBuckets = new byte[bucketCount];
in.readByteArray(rssiBuckets);
+ activeNetworkRssiBoost = in.readInt();
}
@Override
@@ -97,6 +121,7 @@
out.writeInt(bucketWidth);
out.writeInt(rssiBuckets.length);
out.writeByteArray(rssiBuckets);
+ out.writeInt(activeNetworkRssiBoost);
}
/**
@@ -108,6 +133,23 @@
* @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.
@@ -136,12 +178,13 @@
return start == rssiCurve.start &&
bucketWidth == rssiCurve.bucketWidth &&
- Arrays.equals(rssiBuckets, rssiCurve.rssiBuckets);
+ Arrays.equals(rssiBuckets, rssiCurve.rssiBuckets) &&
+ activeNetworkRssiBoost == rssiCurve.activeNetworkRssiBoost;
}
@Override
public int hashCode() {
- return Objects.hash(start, bucketWidth, rssiBuckets);
+ return Objects.hash(start, bucketWidth, rssiBuckets, activeNetworkRssiBoost);
}
@Override
@@ -150,7 +193,9 @@
sb.append("RssiCurve[start=")
.append(start)
.append(",bucketWidth=")
- .append(bucketWidth);
+ .append(bucketWidth)
+ .append(",activeNetworkRssiBoost=")
+ .append(activeNetworkRssiBoost);
sb.append(",buckets=");
for (int i = 0; i < rssiBuckets.length; i++) {