From 017e7f90eea67b0ecd002d1ab193f60238ad0555 Mon Sep 17 00:00:00 2001
From: Nathan Harold <nharold@google.com>
Date: Mon, 29 Jan 2018 17:17:10 -0800
Subject: [PATCH] Update hashCode in CellSignalStrength classes

The CellSignalStrength hashCode function was using a
fairly ineffective method of hashing. An External
reporter requested that we fix it. This CL moves to
using the Objects.hash() implementation.

Bug: 22479413
Test: compilation
Change-Id: Ic017ba54ef757fd3ec3e5000ac61108dd836bd8a
---
 .../java/android/telephony/CellSignalStrengthCdma.java     | 6 +++---
 .../java/android/telephony/CellSignalStrengthGsm.java      | 5 +++--
 .../java/android/telephony/CellSignalStrengthLte.java      | 7 +++----
 .../java/android/telephony/CellSignalStrengthWcdma.java    | 5 +++--
 4 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/telephony/java/android/telephony/CellSignalStrengthCdma.java b/telephony/java/android/telephony/CellSignalStrengthCdma.java
index 047436207ada9..dfaaab9180125 100644
--- a/telephony/java/android/telephony/CellSignalStrengthCdma.java
+++ b/telephony/java/android/telephony/CellSignalStrengthCdma.java
@@ -20,6 +20,8 @@ import android.os.Parcel;
 import android.os.Parcelable;
 import android.telephony.Rlog;
 
+import java.util.Objects;
+
 /**
  * Signal strength related information.
  */
@@ -293,9 +295,7 @@ public final class CellSignalStrengthCdma extends CellSignalStrength implements
 
     @Override
     public int hashCode() {
-        int primeNum = 31;
-        return ((mCdmaDbm * primeNum) + (mCdmaEcio * primeNum)
-                + (mEvdoDbm * primeNum) + (mEvdoEcio * primeNum) + (mEvdoSnr * primeNum));
+        return Objects.hash(mCdmaDbm, mCdmaEcio, mEvdoDbm, mEvdoEcio, mEvdoSnr);
     }
 
     @Override
diff --git a/telephony/java/android/telephony/CellSignalStrengthGsm.java b/telephony/java/android/telephony/CellSignalStrengthGsm.java
index 4137853e79aa8..f68d2cad12260 100644
--- a/telephony/java/android/telephony/CellSignalStrengthGsm.java
+++ b/telephony/java/android/telephony/CellSignalStrengthGsm.java
@@ -20,6 +20,8 @@ import android.os.Parcel;
 import android.os.Parcelable;
 import android.telephony.Rlog;
 
+import java.util.Objects;
+
 /**
  * GSM signal strength related information.
  */
@@ -185,8 +187,7 @@ public final class CellSignalStrengthGsm extends CellSignalStrength implements P
 
     @Override
     public int hashCode() {
-        int primeNum = 31;
-        return (mSignalStrength * primeNum) + (mBitErrorRate * primeNum);
+        return Objects.hash(mSignalStrength, mBitErrorRate, mTimingAdvance);
     }
 
     @Override
diff --git a/telephony/java/android/telephony/CellSignalStrengthLte.java b/telephony/java/android/telephony/CellSignalStrengthLte.java
index 0d07a40822d4c..6ffc8b6e497c3 100644
--- a/telephony/java/android/telephony/CellSignalStrengthLte.java
+++ b/telephony/java/android/telephony/CellSignalStrengthLte.java
@@ -20,6 +20,8 @@ import android.os.Parcel;
 import android.os.Parcelable;
 import android.telephony.Rlog;
 
+import java.util.Objects;
+
 /**
  * LTE signal strength related information.
  */
@@ -231,10 +233,7 @@ public final class CellSignalStrengthLte extends CellSignalStrength implements P
 
     @Override
     public int hashCode() {
-        int primeNum = 31;
-        return (mSignalStrength * primeNum) + (mRsrp * primeNum)
-                + (mRsrq * primeNum) + (mRssnr * primeNum) + (mCqi * primeNum)
-                + (mTimingAdvance * primeNum);
+        return Objects.hash(mSignalStrength, mRsrp, mRsrq, mRssnr, mCqi, mTimingAdvance);
     }
 
     @Override
diff --git a/telephony/java/android/telephony/CellSignalStrengthWcdma.java b/telephony/java/android/telephony/CellSignalStrengthWcdma.java
index b94b01da87bba..2cd56b8500a67 100644
--- a/telephony/java/android/telephony/CellSignalStrengthWcdma.java
+++ b/telephony/java/android/telephony/CellSignalStrengthWcdma.java
@@ -20,6 +20,8 @@ import android.os.Parcel;
 import android.os.Parcelable;
 import android.telephony.Rlog;
 
+import java.util.Objects;
+
 /**
  * Wcdma signal strength related information.
  */
@@ -156,8 +158,7 @@ public final class CellSignalStrengthWcdma extends CellSignalStrength implements
 
     @Override
     public int hashCode() {
-        int primeNum = 31;
-        return (mSignalStrength * primeNum) + (mBitErrorRate * primeNum);
+        return Objects.hash(mSignalStrength, mBitErrorRate);
     }
 
     @Override