handle negative temperature

When the battery temperature drops to below zero, BatteryLevelInit()
fails to show negative temperature. Because the type is unsigned
and the size of bit field is 10 bits.
So to handle negative temperature, change the type of battery temperature
from "char" to "short". And extend the size of temperature bit field
from 10 to 11 bits, which first bit is used for the sign bit.

Before:
31             24                    14                 0
+---------------+---------------------+-----------------+
| Battery Level | Battery temperature | Battery Voltage |
+---------------+---------------------+-----------------+

After:
31           25                      14                 0
+-------------+-----------------------+-----------------+
|Battery Level|  Battery temperature  | Battery Voltage |
+-------------+-----------------------+-----------------+

Bits 31..25: battery level percentage (7 bits unsigned)
Bits 24..14: battery temperature (11 bits signed)
    First bit is used for the sign and others for the temperature
Bits 13..0: battery voltage in 0.001 volt units (14 bits unsigned)

Becuase of changing the format, let the BatteryStatsImpl.VERSION field
increment.

Bug: 8009514
Change-Id: Iaa12f4d3f14e6cf4d73bc1a23d81c60f9677a499

2 files changed, 11 insertions, 11 deletions

diff --git a/core/java/android/os/BatteryStats.java b/core/java/android/os/BatteryStats.java
index 499ec77e3d09..8804066ebeea 100644
--- a/core/java/android/os/BatteryStats.java
+++ b/core/java/android/os/BatteryStats.java
@@ -444,7 +444,7 @@ public abstract class BatteryStats implements Parcelable {
         public byte batteryHealth;
         public byte batteryPlugType;
         
-        public char batteryTemperature;
+        public short batteryTemperature;
         public char batteryVoltage;
         
         // Constants from SCREEN_BRIGHTNESS_*
@@ -521,7 +521,7 @@ public abstract class BatteryStats implements Parcelable {
             batteryHealth = (byte)((bat>>20)&0xf);
             batteryPlugType = (byte)((bat>>24)&0xf);
             bat = src.readInt();
-            batteryTemperature = (char)(bat&0xffff);
+            batteryTemperature = (short)(bat&0xffff);
             batteryVoltage = (char)((bat>>16)&0xffff);
             states = src.readInt();
         }
@@ -590,7 +590,7 @@ public abstract class BatteryStats implements Parcelable {
                 if (DEBUG) Slog.i(TAG, "WRITE DELTA: batteryToken=0x"
                         + Integer.toHexString(batteryLevelInt)
                         + " batteryLevel=" + batteryLevel
-                        + " batteryTemp=" + (int)batteryTemperature
+                        + " batteryTemp=" + batteryTemperature
                         + " batteryVolt=" + (int)batteryVoltage);
             }
             if (stateIntChanged) {
@@ -605,8 +605,8 @@ public abstract class BatteryStats implements Parcelable {
         }
         
         private int buildBatteryLevelInt() {
-            return ((((int)batteryLevel)<<24)&0xff000000)
-                    | ((((int)batteryTemperature)<<14)&0x00ffc000)
+            return ((((int)batteryLevel)<<25)&0xfe000000)
+                    | ((((int)batteryTemperature)<<14)&0x01ffc000)
                     | (((int)batteryVoltage)&0x00003fff);
         }
         
@@ -642,13 +642,13 @@ public abstract class BatteryStats implements Parcelable {
             
             if ((firstToken&DELTA_BATTERY_LEVEL_FLAG) != 0) {
                 int batteryLevelInt = src.readInt();
-                batteryLevel = (byte)((batteryLevelInt>>24)&0xff);
-                batteryTemperature = (char)((batteryLevelInt>>14)&0x3ff);
+                batteryLevel = (byte)((batteryLevelInt>>25)&0x7f);
+                batteryTemperature = (short)((batteryLevelInt<<7)>>21);
                 batteryVoltage = (char)(batteryLevelInt&0x3fff);
                 if (DEBUG) Slog.i(TAG, "READ DELTA: batteryToken=0x"
                         + Integer.toHexString(batteryLevelInt)
                         + " batteryLevel=" + batteryLevel
-                        + " batteryTemp=" + (int)batteryTemperature
+                        + " batteryTemp=" + batteryTemperature
                         + " batteryVolt=" + (int)batteryVoltage);
             }
             
diff --git a/core/java/com/android/internal/os/BatteryStatsImpl.java b/core/java/com/android/internal/os/BatteryStatsImpl.java
index 6375dbe6cf89..778693aba913 100644
--- a/core/java/com/android/internal/os/BatteryStatsImpl.java
+++ b/core/java/com/android/internal/os/BatteryStatsImpl.java
@@ -83,7 +83,7 @@ public final class BatteryStatsImpl extends BatteryStats {
     private static final int MAGIC = 0xBA757475; // 'BATSTATS'
 
     // Current on-disk Parcel version
-    private static final int VERSION = 64 + (USE_OLD_HISTORY ? 1000 : 0);
+    private static final int VERSION = 65 + (USE_OLD_HISTORY ? 1000 : 0);
 
     // Maximum number of items we will record in the history.
     private static final int MAX_HISTORY_ITEMS = 2000;
@@ -4611,7 +4611,7 @@ public final class BatteryStatsImpl extends BatteryStats {
                 mHistoryCur.batteryStatus = (byte)status;
                 mHistoryCur.batteryHealth = (byte)health;
                 mHistoryCur.batteryPlugType = (byte)plugType;
-                mHistoryCur.batteryTemperature = (char)temp;
+                mHistoryCur.batteryTemperature = (short)temp;
                 mHistoryCur.batteryVoltage = (char)volt;
                 setOnBatteryLocked(onBattery, oldStatus, level);
             } else {
@@ -4634,7 +4634,7 @@ public final class BatteryStatsImpl extends BatteryStats {
                 }
                 if (temp >= (mHistoryCur.batteryTemperature+10)
                         || temp <= (mHistoryCur.batteryTemperature-10)) {
-                    mHistoryCur.batteryTemperature = (char)temp;
+                    mHistoryCur.batteryTemperature = (short)temp;
                     changed = true;
                 }
                 if (volt > (mHistoryCur.batteryVoltage+20)