Compute range-based usage in NetworkStatsHistory.

When given a start/end range, interpolate between buckets to return
the total network usage.  Used to summarize detailed UID stats.  Method
to combine NetworkStatsHistory regardless of bucket size.  Used to
combine all histories matching a template.

Added tests for both methods.

Change-Id: Ia463910c0ecf7cf08dcf97c658ad99742bd6b882

core/tests/coretests/src/android/net/NetworkStatsHistoryTest.java

@@ -133,9 +133,80 @@ public class NetworkStatsHistoryTest extends TestCase {
         assertBucket(stats, 1, 512L, 512L);
     }
 
+    public void testRecordEntireGapIdentical() throws Exception {
+        final long[] total = new long[2];
+
+        // first, create two separate histories far apart
+        final NetworkStatsHistory stats1 = new NetworkStatsHistory(HOUR_IN_MILLIS);
+        stats1.recordData(TEST_START, TEST_START + 2 * HOUR_IN_MILLIS, 2000L, 1000L);
+
+        final long TEST_START_2 = TEST_START + DAY_IN_MILLIS;
+        final NetworkStatsHistory stats2 = new NetworkStatsHistory(HOUR_IN_MILLIS);
+        stats2.recordData(TEST_START_2, TEST_START_2 + 2 * HOUR_IN_MILLIS, 1000L, 500L);
+
+        // combine together with identical bucket size
+        stats = new NetworkStatsHistory(HOUR_IN_MILLIS);
+        stats.recordEntireHistory(stats1);
+        stats.recordEntireHistory(stats2);
+
+        // first verify that totals match up
+        stats.getTotalData(TEST_START - WEEK_IN_MILLIS, TEST_START + WEEK_IN_MILLIS, total);
+        assertTotalEquals(total, 3000L, 1500L);
+
+        // now inspect internal buckets
+        assertBucket(stats, 0, 1000L, 500L);
+        assertBucket(stats, 1, 1000L, 500L);
+        assertBucket(stats, 2, 500L, 250L);
+        assertBucket(stats, 3, 500L, 250L);
+    }
+
+    public void testRecordEntireOverlapVaryingBuckets() throws Exception {
+        final long[] total = new long[2];
+
+        // create history just over hour bucket boundary
+        final NetworkStatsHistory stats1 = new NetworkStatsHistory(HOUR_IN_MILLIS);
+        stats1.recordData(TEST_START, TEST_START + MINUTE_IN_MILLIS * 60, 600L, 600L);
+
+        final long TEST_START_2 = TEST_START + MINUTE_IN_MILLIS;
+        final NetworkStatsHistory stats2 = new NetworkStatsHistory(MINUTE_IN_MILLIS);
+        stats2.recordData(TEST_START_2, TEST_START_2 + MINUTE_IN_MILLIS * 5, 50L, 50L);
+
+        // combine together with minute bucket size
+        stats = new NetworkStatsHistory(MINUTE_IN_MILLIS);
+        stats.recordEntireHistory(stats1);
+        stats.recordEntireHistory(stats2);
+
+        // first verify that totals match up
+        stats.getTotalData(TEST_START - WEEK_IN_MILLIS, TEST_START + WEEK_IN_MILLIS, total);
+        assertTotalEquals(total, 650L, 650L);
+
+        // now inspect internal buckets
+        assertBucket(stats, 0, 10L, 10L);
+        assertBucket(stats, 1, 20L, 20L);
+        assertBucket(stats, 2, 20L, 20L);
+        assertBucket(stats, 3, 20L, 20L);
+        assertBucket(stats, 4, 20L, 20L);
+        assertBucket(stats, 5, 20L, 20L);
+        assertBucket(stats, 6, 10L, 10L);
+
+        // now combine using 15min buckets
+        stats = new NetworkStatsHistory(HOUR_IN_MILLIS / 4);
+        stats.recordEntireHistory(stats1);
+        stats.recordEntireHistory(stats2);
+
+        // first verify that totals match up
+        stats.getTotalData(TEST_START - WEEK_IN_MILLIS, TEST_START + WEEK_IN_MILLIS, total);
+        assertTotalEquals(total, 650L, 650L);
+
+        // and inspect buckets
+        assertBucket(stats, 0, 200L, 200L);
+        assertBucket(stats, 1, 150L, 150L);
+        assertBucket(stats, 2, 150L, 150L);
+        assertBucket(stats, 3, 150L, 150L);
+    }
+
     public void testRemove() throws Exception {
-        final long BUCKET_SIZE = HOUR_IN_MILLIS;
+        stats = new NetworkStatsHistory(HOUR_IN_MILLIS);
-        stats = new NetworkStatsHistory(BUCKET_SIZE);
 
         // record some data across 24 buckets
         stats.recordData(TEST_START, TEST_START + DAY_IN_MILLIS, 24L, 24L);
@@ -163,6 +234,37 @@ public class NetworkStatsHistoryTest extends TestCase {
         assertEquals(0, stats.bucketCount);
     }
 
+    public void testTotalData() throws Exception {
+        final long BUCKET_SIZE = HOUR_IN_MILLIS;
+        stats = new NetworkStatsHistory(BUCKET_SIZE);
+
+        // record uniform data across day
+        stats.recordData(TEST_START, TEST_START + DAY_IN_MILLIS, 2400L, 4800L);
+
+        final long[] total = new long[2];
+
+        // verify that total outside range is 0
+        stats.getTotalData(TEST_START - WEEK_IN_MILLIS, TEST_START - DAY_IN_MILLIS, total);
+        assertTotalEquals(total, 0, 0);
+
+        // verify total in first hour
+        stats.getTotalData(TEST_START, TEST_START + HOUR_IN_MILLIS, total);
+        assertTotalEquals(total, 100, 200);
+
+        // verify total across 1.5 hours
+        stats.getTotalData(TEST_START, TEST_START + (long) (1.5 * HOUR_IN_MILLIS), total);
+        assertTotalEquals(total, 150, 300);
+
+        // verify total beyond end
+        stats.getTotalData(TEST_START + (23 * HOUR_IN_MILLIS), TEST_START + WEEK_IN_MILLIS, total);
+        assertTotalEquals(total, 100, 200);
+
+        // verify everything total
+        stats.getTotalData(TEST_START - WEEK_IN_MILLIS, TEST_START + WEEK_IN_MILLIS, total);
+        assertTotalEquals(total, 2400, 4800);
+
+    }
+
     @Suppress
     public void testFuzzing() throws Exception {
         try {
@@ -196,6 +298,11 @@ public class NetworkStatsHistoryTest extends TestCase {
         }
     }
 
+    private static void assertTotalEquals(long[] total, long rx, long tx) {
+        assertEquals("unexpected rx", rx, total[0]);
+        assertEquals("unexpected tx", tx, total[1]);
+    }
+
     private static void assertBucket(NetworkStatsHistory stats, int index, long rx, long tx) {
         assertEquals("unexpected rx", rx, stats.rx[index]);
         assertEquals("unexpected tx", tx, stats.tx[index]);