Add third_party/android_data_chart for data chart widget.

third_party/android_misc/java/src/org/chromium/third_party/android/datausagechart/NetworkStatsHistory.java

Index: third_party/android_misc/java/src/org/chromium/third_party/android/datausagechart/NetworkStatsHistory.java
diff --git a/third_party/android_misc/java/src/org/chromium/third_party/android/datausagechart/NetworkStatsHistory.java b/third_party/android_misc/java/src/org/chromium/third_party/android/datausagechart/NetworkStatsHistory.java
new file mode 100644
index 0000000000000000000000000000000000000000..01f98e912edd703fc405400faafe138da0c0d8ef
--- /dev/null
+++ b/third_party/android_misc/java/src/org/chromium/third_party/android/datausagechart/NetworkStatsHistory.java
@@ -0,0 +1,737 @@
+/*
+ * Copyright (C) 2011 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 org.chromium.third_party.android.datausagechart;
+
+import static org.chromium.third_party.android.datausagechart.NetworkStatsHistory.DataStreamUtils.readFullLongArray;
+import static org.chromium.third_party.android.datausagechart.NetworkStatsHistory.DataStreamUtils.readVarLongArray;
+import static org.chromium.third_party.android.datausagechart.NetworkStatsHistory.DataStreamUtils.writeVarLongArray;
+import static org.chromium.third_party.android.datausagechart.NetworkStatsHistory.Entry.UNKNOWN;
+import static org.chromium.third_party.android.datausagechart.NetworkStatsHistory.ParcelUtils.readLongArray;
+import static org.chromium.third_party.android.datausagechart.NetworkStatsHistory.ParcelUtils.writeLongArray;
+
+import android.os.Parcel;
+import android.os.Parcelable;
+
+import java.io.CharArrayWriter;
+import java.io.DataInputStream;
+import java.io.DataOutputStream;
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.net.ProtocolException;
+import java.util.Arrays;
+import java.util.Random;
+
+/**
+ * Collection of historical network statistics, recorded into equally-sized
+ * "buckets" in time. Internally it stores data in {@code long} series for more
+ * efficient persistence.
+ * <p>
+ * Each bucket is defined by a {@link #bucketStart} timestamp, and lasts for
+ * {@link #bucketDuration}. Internally assumes that {@link #bucketStart} is
+ * sorted at all times.
+ * This is derived from android.net.NetworkStatsHistory.
+ * @hide
+ */
+public class NetworkStatsHistory implements Parcelable {
+    private static final int VERSION_INIT = 1;
+    private static final int VERSION_ADD_PACKETS = 2;
+    private static final int VERSION_ADD_ACTIVE = 3;
+
+    public static final int FIELD_ACTIVE_TIME = 0x01;
+    public static final int FIELD_RX_BYTES = 0x02;
+    public static final int FIELD_RX_PACKETS = 0x04;
+    public static final int FIELD_TX_BYTES = 0x08;
+    public static final int FIELD_TX_PACKETS = 0x10;
+    public static final int FIELD_OPERATIONS = 0x20;
+
+    public static final int FIELD_ALL = 0xFFFFFFFF;
+
+    public static final String IFACE_ALL = null;
+    public static final int SET_DEFAULT = 0;
+    public static final int TAG_NONE = 0;
+    public static final int UID_ALL = -1;
+
+    private long bucketDuration;
+    private int bucketCount;
+    private long[] bucketStart;
+    private long[] activeTime;
+    private long[] rxBytes;
+    private long[] rxPackets;
+    private long[] txBytes;
+    private long[] txPackets;
+    private long[] operations;
+    private long totalBytes;
+
+    public static class Entry {
+        public static final long UNKNOWN = -1;
+
+        public long bucketDuration;
+        public long bucketStart;
+        public long activeTime;
+        public long rxBytes;
+        public long rxPackets;
+        public long txBytes;
+        public long txPackets;
+        public long operations;
+    }
+
+    public NetworkStatsHistory(long bucketDuration) {
+        this(bucketDuration, 10, FIELD_ALL);
+    }
+
+    public NetworkStatsHistory(long bucketDuration, int initialSize) {
+        this(bucketDuration, initialSize, FIELD_ALL);
+    }
+
+    public NetworkStatsHistory(long bucketDuration, int initialSize, int fields) {
+        this.bucketDuration = bucketDuration;
+        bucketStart = new long[initialSize];
+        if ((fields & FIELD_ACTIVE_TIME) != 0) activeTime = new long[initialSize];
+        if ((fields & FIELD_RX_BYTES) != 0) rxBytes = new long[initialSize];
+        if ((fields & FIELD_RX_PACKETS) != 0) rxPackets = new long[initialSize];
+        if ((fields & FIELD_TX_BYTES) != 0) txBytes = new long[initialSize];
+        if ((fields & FIELD_TX_PACKETS) != 0) txPackets = new long[initialSize];
+        if ((fields & FIELD_OPERATIONS) != 0) operations = new long[initialSize];
+        bucketCount = 0;
+        totalBytes = 0;
+    }
+
+    public NetworkStatsHistory(NetworkStatsHistory existing, long bucketDuration) {
+        this(bucketDuration, existing.estimateResizeBuckets(bucketDuration));
+        recordEntireHistory(existing);
+    }
+
+    public NetworkStatsHistory(Parcel in) {
+        bucketDuration = in.readLong();
+        bucketStart = readLongArray(in);
+        activeTime = readLongArray(in);
+        rxBytes = readLongArray(in);
+        rxPackets = readLongArray(in);
+        txBytes = readLongArray(in);
+        txPackets = readLongArray(in);
+        operations = readLongArray(in);
+        bucketCount = bucketStart.length;
+        totalBytes = in.readLong();
+    }
+
+    @Override
+    public void writeToParcel(Parcel out, int flags) {
+        out.writeLong(bucketDuration);
+        writeLongArray(out, bucketStart, bucketCount);
+        writeLongArray(out, activeTime, bucketCount);
+        writeLongArray(out, rxBytes, bucketCount);
+        writeLongArray(out, rxPackets, bucketCount);
+        writeLongArray(out, txBytes, bucketCount);
+        writeLongArray(out, txPackets, bucketCount);
+        writeLongArray(out, operations, bucketCount);
+        out.writeLong(totalBytes);
+    }
+
+    private long total(long[] list) {
+        long sum = 0L;
+        for (int i = 0; i < list.length; i++) {
+            sum += list[i];
+        }
+        return sum;
+    }
+
+    public NetworkStatsHistory(DataInputStream in) throws IOException {
+        final int version = in.readInt();
+        switch (version) {
+            case VERSION_INIT: {
+                bucketDuration = in.readLong();
+                bucketStart = readFullLongArray(in);
+                rxBytes = readFullLongArray(in);
+                rxPackets = new long[bucketStart.length];
+                txBytes = readFullLongArray(in);
+                txPackets = new long[bucketStart.length];
+                operations = new long[bucketStart.length];
+                bucketCount = bucketStart.length;
+                totalBytes = total(rxBytes) + total(txBytes);
+                break;
+            }
+            case VERSION_ADD_PACKETS:
+            case VERSION_ADD_ACTIVE: {
+                bucketDuration = in.readLong();
+                bucketStart = readVarLongArray(in);
+                activeTime = (version >= VERSION_ADD_ACTIVE) ? readVarLongArray(in)
+                        : new long[bucketStart.length];
+                rxBytes = readVarLongArray(in);
+                rxPackets = readVarLongArray(in);
+                txBytes = readVarLongArray(in);
+                txPackets = readVarLongArray(in);
+                operations = readVarLongArray(in);
+                bucketCount = bucketStart.length;
+                totalBytes = total(rxBytes) + total(txBytes);
+                break;
+            }
+            default: {
+                throw new ProtocolException("unexpected version: " + version);
+            }
+        }
+
+        if (bucketStart.length != bucketCount || rxBytes.length != bucketCount
+                || rxPackets.length != bucketCount || txBytes.length != bucketCount
+                || txPackets.length != bucketCount || operations.length != bucketCount) {
+            throw new ProtocolException("Mismatched history lengths");
+        }
+    }
+
+    public void writeToStream(DataOutputStream out) throws IOException {
+        out.writeInt(VERSION_ADD_ACTIVE);
+        out.writeLong(bucketDuration);
+        writeVarLongArray(out, bucketStart, bucketCount);
+        writeVarLongArray(out, activeTime, bucketCount);
+        writeVarLongArray(out, rxBytes, bucketCount);
+        writeVarLongArray(out, rxPackets, bucketCount);
+        writeVarLongArray(out, txBytes, bucketCount);
+        writeVarLongArray(out, txPackets, bucketCount);
+        writeVarLongArray(out, operations, bucketCount);
+    }
+
+    @Override
+    public int describeContents() {
+        return 0;
+    }
+
+    public int size() {
+        return bucketCount;
+    }
+
+    public long getBucketDuration() {
+        return bucketDuration;
+    }
+
+    public long getStart() {
+        if (bucketCount > 0) {
+            return bucketStart[0];
+        } else {
+            return Long.MAX_VALUE;
+        }
+    }
+
+    public long getEnd() {
+        if (bucketCount > 0) {
+            return bucketStart[bucketCount - 1] + bucketDuration;
+        } else {
+            return Long.MIN_VALUE;
+        }
+    }
+
+    /**
+     * Return total bytes represented by this history.

[bengr, 2015/01/26 19:25:00]

Returns

Here and below.

+     */
+    public long getTotalBytes() {
+        return totalBytes;
+    }
+
+    /**
+     * Return index of bucket that contains or is immediately before the
+     * requested time.
+     */
+    public int getIndexBefore(long time) {
+        int index = Arrays.binarySearch(bucketStart, 0, bucketCount, time);
+        if (index < 0) {
+            index = (~index) - 1;
+        } else {
+            index -= 1;
+        }
+        return Math.max(0, Math.min(bucketCount - 1, index));
+    }
+
+    /**
+     * Return index of bucket that contains or is immediately after the
+     * requested time.
+     */
+    public int getIndexAfter(long time) {
+        int index = Arrays.binarySearch(bucketStart, 0, bucketCount, time);
+        if (index < 0) {
+            index = ~index;
+        } else {
+            index += 1;
+        }
+        return Math.max(0, Math.min(bucketCount - 1, index));
+    }
+
+    /**
+     * Return specific stats entry.
+     */
+    public Entry getValues(int i, Entry recycle) {
+        final Entry entry = recycle != null ? recycle : new Entry();
+        entry.bucketStart = bucketStart[i];
+        entry.bucketDuration = bucketDuration;
+        entry.activeTime = getLong(activeTime, i, UNKNOWN);
+        entry.rxBytes = getLong(rxBytes, i, UNKNOWN);
+        entry.rxPackets = getLong(rxPackets, i, UNKNOWN);
+        entry.txBytes = getLong(txBytes, i, UNKNOWN);
+        entry.txPackets = getLong(txPackets, i, UNKNOWN);
+        entry.operations = getLong(operations, i, UNKNOWN);
+        return entry;
+    }
+
+    /**
+     * Record that data traffic occurred in the given time range. Will

[bengr, 2015/01/26 19:25:00]

Records

Here and below.

+     * distribute across internal buckets, creating new buckets as needed.
+     */
+    @Deprecated
+    public void recordData(long start, long end, long rxBytes, long txBytes) {
+        recordData(start, end, new NetworkStats.Entry(
+                IFACE_ALL, UID_ALL, SET_DEFAULT, TAG_NONE, rxBytes, 0L, txBytes, 0L, 0L));
+    }
+
+    /**
+     * Record that data traffic occurred in the given time range. Will
+     * distribute across internal buckets, creating new buckets as needed.
+     */
+    public void recordData(long start, long end, NetworkStats.Entry entry) {
+        long rxBytes = entry.rxBytes;
+        long rxPackets = entry.rxPackets;
+        long txBytes = entry.txBytes;
+        long txPackets = entry.txPackets;
+        long operations = entry.operations;
+
+        if (entry.isNegative()) {
+            throw new IllegalArgumentException("tried recording negative data");
+        }
+
+        // create any buckets needed by this range

[bengr, 2015/01/26 19:24:59]

Create .. range.

+        ensureBuckets(start, end);
+
+        // distribute data usage into buckets

[bengr, 2015/01/26 19:25:00]

Distribute .. buckets.

+        long duration = end - start;
+        final int startIndex = getIndexAfter(end);
+        for (int i = startIndex; i >= 0; i--) {
+            final long curStart = bucketStart[i];
+            final long curEnd = curStart + bucketDuration;
+
+            // bucket is older than record; we're finished

[bengr, 2015/01/26 19:25:00]

// Finished because bucket is older than record. 

+            if (curEnd < start) break;
+            // bucket is newer than record; keep looking

[bengr, 2015/01/26 19:24:59]

// Keep looking because bucket is newer than record.

+            if (curStart > end) continue;
+
+            final long overlap = Math.min(curEnd, end) - Math.max(curStart, start);
+            if (overlap <= 0) continue;
+
+            // integer math each time is faster than floating point

[bengr, 2015/01/26 19:24:59]

Integer .. point.

+            final long fracRxBytes = rxBytes * overlap / duration;
+            final long fracRxPackets = rxPackets * overlap / duration;
+            final long fracTxBytes = txBytes * overlap / duration;
+            final long fracTxPackets = txPackets * overlap / duration;
+            final long fracOperations = operations * overlap / duration;
+
+            addLong(activeTime, i, overlap);
+            addLong(this.rxBytes, i, fracRxBytes); rxBytes -= fracRxBytes;
+            addLong(this.rxPackets, i, fracRxPackets); rxPackets -= fracRxPackets;
+            addLong(this.txBytes, i, fracTxBytes); txBytes -= fracTxBytes;
+            addLong(this.txPackets, i, fracTxPackets); txPackets -= fracTxPackets;
+            addLong(this.operations, i, fracOperations); operations -= fracOperations;
+
+            duration -= overlap;
+        }
+
+        totalBytes += entry.rxBytes + entry.txBytes;
+    }
+
+    /**
+     * Record an entire {@link NetworkStatsHistory} into this history. Usually
+     * for combining together stats for external reporting.
+     */
+    public void recordEntireHistory(NetworkStatsHistory input) {
+        recordHistory(input, Long.MIN_VALUE, Long.MAX_VALUE);
+    }
+
+    /**
+     * Record given {@link NetworkStatsHistory} into this history, copying only
+     * buckets that atomically occur in the inclusive time range. Doesn't
+     * interpolate across partial buckets.
+     */
+    public void recordHistory(NetworkStatsHistory input, long start, long end) {
+        final NetworkStats.Entry entry = new NetworkStats.Entry(
+                IFACE_ALL, UID_ALL, SET_DEFAULT, TAG_NONE, 0L, 0L, 0L, 0L, 0L);
+        for (int i = 0; i < input.bucketCount; i++) {
+            final long bucketStart = input.bucketStart[i];
+            final long bucketEnd = bucketStart + input.bucketDuration;
+
+            // skip when bucket is outside requested range
+            if (bucketStart < start || bucketEnd > end) continue;
+
+            entry.rxBytes = getLong(input.rxBytes, i, 0L);
+            entry.rxPackets = getLong(input.rxPackets, i, 0L);
+            entry.txBytes = getLong(input.txBytes, i, 0L);
+            entry.txPackets = getLong(input.txPackets, i, 0L);
+            entry.operations = getLong(input.operations, i, 0L);
+
+            recordData(bucketStart, bucketEnd, entry);
+        }
+    }
+
+    /**
+     * Ensure that buckets exist for given time range, creating as needed.

[bengr, 2015/01/26 19:25:00]

Ensures

+     */
+    private void ensureBuckets(long start, long end) {
+        // normalize incoming range to bucket boundaries
+        start -= start % bucketDuration;
+        end += (bucketDuration - (end % bucketDuration)) % bucketDuration;
+
+        for (long now = start; now < end; now += bucketDuration) {
+            // try finding existing bucket

[bengr, 2015/01/26 19:24:59]

// Try to find an existing bucket.

+            final int index = Arrays.binarySearch(bucketStart, 0, bucketCount, now);
+            if (index < 0) {
+                // bucket missing, create and insert

[bengr, 2015/01/26 19:25:00]

// The bucket is missing. Create one and insert it.

+                insertBucket(~index, now);
+            }
+        }
+    }
+
+    /**
+     * Insert new bucket at requested index and starting time.

[bengr, 2015/01/26 19:24:59]

Inserts

+     */
+    private void insertBucket(int index, long start) {
+        // create more buckets when needed

[bengr, 2015/01/26 19:25:00]

Creates .. needed.

+        if (bucketCount >= bucketStart.length) {
+            final int newLength = Math.max(bucketStart.length, 10) * 3 / 2;
+            bucketStart = Arrays.copyOf(bucketStart, newLength);
+            if (activeTime != null) activeTime = Arrays.copyOf(activeTime, newLength);
+            if (rxBytes != null) rxBytes = Arrays.copyOf(rxBytes, newLength);
+            if (rxPackets != null) rxPackets = Arrays.copyOf(rxPackets, newLength);
+            if (txBytes != null) txBytes = Arrays.copyOf(txBytes, newLength);
+            if (txPackets != null) txPackets = Arrays.copyOf(txPackets, newLength);
+            if (operations != null) operations = Arrays.copyOf(operations, newLength);
+        }
+
+        // create gap when inserting bucket in middle

[bengr, 2015/01/26 19:25:00]

Create .. middle.

+        if (index < bucketCount) {
+            final int dstPos = index + 1;
+            final int length = bucketCount - index;
+
+            System.arraycopy(bucketStart, index, bucketStart, dstPos, length);
+            if (activeTime != null) System.arraycopy(activeTime, index, activeTime, dstPos, length);
+            if (rxBytes != null) System.arraycopy(rxBytes, index, rxBytes, dstPos, length);
+            if (rxPackets != null) System.arraycopy(rxPackets, index, rxPackets, dstPos, length);
+            if (txBytes != null) System.arraycopy(txBytes, index, txBytes, dstPos, length);
+            if (txPackets != null) System.arraycopy(txPackets, index, txPackets, dstPos, length);
+            if (operations != null) System.arraycopy(operations, index, operations, dstPos, length);
+        }
+
+        bucketStart[index] = start;
+        setLong(activeTime, index, 0L);
+        setLong(rxBytes, index, 0L);
+        setLong(rxPackets, index, 0L);
+        setLong(txBytes, index, 0L);
+        setLong(txPackets, index, 0L);
+        setLong(operations, index, 0L);
+        bucketCount++;
+    }
+
+    /**
+     * Remove buckets older than requested cutoff.

[bengr, 2015/01/26 19:25:00]

Removes

+     */
+    @Deprecated
+    public void removeBucketsBefore(long cutoff) {
+        int i;
+        for (i = 0; i < bucketCount; i++) {
+            final long curStart = bucketStart[i];
+            final long curEnd = curStart + bucketDuration;
+
+            // cutoff happens before or during this bucket; everything before

[bengr, 2015/01/26 19:24:59]

The cutoff

+            // this bucket should be removed.
+            if (curEnd > cutoff) break;
+        }
+
+        if (i > 0) {
+            final int length = bucketStart.length;
+            bucketStart = Arrays.copyOfRange(bucketStart, i, length);
+            if (activeTime != null) activeTime = Arrays.copyOfRange(activeTime, i, length);
+            if (rxBytes != null) rxBytes = Arrays.copyOfRange(rxBytes, i, length);
+            if (rxPackets != null) rxPackets = Arrays.copyOfRange(rxPackets, i, length);
+            if (txBytes != null) txBytes = Arrays.copyOfRange(txBytes, i, length);
+            if (txPackets != null) txPackets = Arrays.copyOfRange(txPackets, i, length);
+            if (operations != null) operations = Arrays.copyOfRange(operations, i, length);
+            bucketCount -= i;
+
+            // TODO: subtract removed values from totalBytes
+        }
+    }
+
+    /**
+     * Return interpolated data usage across the requested range. Interpolates
+     * across buckets, so values may be rounded slightly.
+     */
+    public Entry getValues(long start, long end, Entry recycle) {
+        return getValues(start, end, Long.MAX_VALUE, recycle);
+    }
+
+    /**
+     * Return interpolated data usage across the requested range. Interpolates
+     * across buckets, so values may be rounded slightly.
+     */
+    public Entry getValues(long start, long end, long now, Entry recycle) {
+        final Entry entry = recycle != null ? recycle : new Entry();
+        entry.bucketDuration = end - start;
+        entry.bucketStart = start;
+        entry.activeTime = activeTime != null ? 0 : UNKNOWN;
+        entry.rxBytes = rxBytes != null ? 0 : UNKNOWN;
+        entry.rxPackets = rxPackets != null ? 0 : UNKNOWN;
+        entry.txBytes = txBytes != null ? 0 : UNKNOWN;
+        entry.txPackets = txPackets != null ? 0 : UNKNOWN;
+        entry.operations = operations != null ? 0 : UNKNOWN;
+
+        final int startIndex = getIndexAfter(end);
+        for (int i = startIndex; i >= 0; i--) {
+            final long curStart = bucketStart[i];
+            final long curEnd = curStart + bucketDuration;
+
+            // bucket is older than request; we're finished

[bengr, 2015/01/26 19:25:00]

Fix all comments to be complete sentences.

+            if (curEnd <= start) break;
+            // bucket is newer than request; keep looking
+            if (curStart >= end) continue;
+
+            // include full value for active buckets, otherwise only fractional
+            final boolean activeBucket = curStart < now && curEnd > now;
+            final long overlap;
+            if (activeBucket) {
+                overlap = bucketDuration;
+            } else {
+                final long overlapEnd = curEnd < end ? curEnd : end;
+                final long overlapStart = curStart > start ? curStart : start;
+                overlap = overlapEnd - overlapStart;
+            }
+            if (overlap <= 0) continue;
+
+            // integer math each time is faster than floating point
+            if (activeTime != null) entry.activeTime += activeTime[i] * overlap / bucketDuration;
+            if (rxBytes != null) entry.rxBytes += rxBytes[i] * overlap / bucketDuration;
+            if (rxPackets != null) entry.rxPackets += rxPackets[i] * overlap / bucketDuration;
+            if (txBytes != null) entry.txBytes += txBytes[i] * overlap / bucketDuration;
+            if (txPackets != null) entry.txPackets += txPackets[i] * overlap / bucketDuration;
+            if (operations != null) entry.operations += operations[i] * overlap / bucketDuration;
+        }
+        return entry;
+    }
+
+    /**
+     * @deprecated only for temporary testing
+     */
+    @Deprecated
+    public void generateRandom(long start, long end, long bytes) {
+        final Random r = new Random();
+
+        final float fractionRx = r.nextFloat();
+        final long rxBytes = (long) (bytes * fractionRx);
+        final long txBytes = (long) (bytes * (1 - fractionRx));
+
+        final long rxPackets = rxBytes / 1024;
+        final long txPackets = txBytes / 1024;
+        final long operations = rxBytes / 2048;
+
+        generateRandom(start, end, rxBytes, rxPackets, txBytes, txPackets, operations, r);
+    }
+
+    /**
+     * @deprecated only for temporary testing
+     */
+    @Deprecated
+    public void generateRandom(long start, long end, long rxBytes, long rxPackets, long txBytes,
+            long txPackets, long operations, Random r) {
+        ensureBuckets(start, end);
+
+        final NetworkStats.Entry entry = new NetworkStats.Entry(
+                IFACE_ALL, UID_ALL, SET_DEFAULT, TAG_NONE, 0L, 0L, 0L, 0L, 0L);
+        while (rxBytes > 1024 || rxPackets > 128 || txBytes > 1024 || txPackets > 128
+                || operations > 32) {
+            final long curStart = randomLong(r, start, end);
+            final long curEnd = curStart + randomLong(r, 0, (end - curStart) / 2);
+
+            entry.rxBytes = randomLong(r, 0, rxBytes);
+            entry.rxPackets = randomLong(r, 0, rxPackets);
+            entry.txBytes = randomLong(r, 0, txBytes);
+            entry.txPackets = randomLong(r, 0, txPackets);
+            entry.operations = randomLong(r, 0, operations);
+
+            rxBytes -= entry.rxBytes;
+            rxPackets -= entry.rxPackets;
+            txBytes -= entry.txBytes;
+            txPackets -= entry.txPackets;
+            operations -= entry.operations;
+
+            recordData(curStart, curEnd, entry);
+        }
+    }
+
+    public static long randomLong(Random r, long start, long end) {
+        return (long) (start + (r.nextFloat() * (end - start)));
+    }
+
+    public void dump(PrintWriter pw, boolean fullHistory) {
+        // TODO(bengr): Use an IndentingPrintWriter.
+        pw.print("NetworkStatsHistory: bucketDuration="); pw.println(bucketDuration);
+
+        final int start = fullHistory ? 0 : Math.max(0, bucketCount - 32);
+        if (start > 0) {
+            pw.print("(omitting "); pw.print(start); pw.println(" buckets)");
+        }
+
+        for (int i = start; i < bucketCount; i++) {
+            pw.print("bucketStart="); pw.print(bucketStart[i]);
+            if (activeTime != null) { pw.print(" activeTime="); pw.print(activeTime[i]); }
+            if (rxBytes != null) { pw.print(" rxBytes="); pw.print(rxBytes[i]); }
+            if (rxPackets != null) { pw.print(" rxPackets="); pw.print(rxPackets[i]); }
+            if (txBytes != null) { pw.print(" txBytes="); pw.print(txBytes[i]); }
+            if (txPackets != null) { pw.print(" txPackets="); pw.print(txPackets[i]); }
+            if (operations != null) { pw.print(" operations="); pw.print(operations[i]); }
+            pw.println();
+        }
+    }
+
+    @Override
+    public String toString() {
+        final CharArrayWriter writer = new CharArrayWriter();
+        dump(new PrintWriter(writer), false);
+        return writer.toString();
+    }
+
+    public static final Creator<NetworkStatsHistory> CREATOR = new Creator<NetworkStatsHistory>() {
+        @Override
+        public NetworkStatsHistory createFromParcel(Parcel in) {
+            return new NetworkStatsHistory(in);
+        }
+
+        @Override
+        public NetworkStatsHistory[] newArray(int size) {
+            return new NetworkStatsHistory[size];
+        }
+    };
+
+    private static long getLong(long[] array, int i, long value) {
+        return array != null ? array[i] : value;
+    }
+
+    private static void setLong(long[] array, int i, long value) {
+        if (array != null) array[i] = value;
+    }
+
+    private static void addLong(long[] array, int i, long value) {
+        if (array != null) array[i] += value;
+    }
+
+    public int estimateResizeBuckets(long newBucketDuration) {
+        return (int) (size() * getBucketDuration() / newBucketDuration);
+    }
+
+    /**
+     * Utility methods for interacting with {@link DataInputStream} and
+     * {@link DataOutputStream}, mostly dealing with writing partial arrays.
+     */
+    public static class DataStreamUtils {
+        @Deprecated
+        public static long[] readFullLongArray(DataInputStream in) throws IOException {
+            final int size = in.readInt();
+            final long[] values = new long[size];
+            for (int i = 0; i < values.length; i++) {
+                values[i] = in.readLong();
+            }
+            return values;
+        }
+
+        /**
+         * Read variable-length {@link Long} using protobuf-style approach.
+         */
+        public static long readVarLong(DataInputStream in) throws IOException {
+            int shift = 0;
+            long result = 0;
+            while (shift < 64) {
+                byte b = in.readByte();
+                result |= (long) (b & 0x7F) << shift;
+                if ((b & 0x80) == 0)
+                    return result;
+                shift += 7;
+            }
+            throw new ProtocolException("malformed long");
+        }
+
+        /**
+         * Write variable-length {@link Long} using protobuf-style approach.
+         */
+        public static void writeVarLong(DataOutputStream out, long value) throws IOException {
+            while (true) {
+                if ((value & ~0x7FL) == 0) {
+                    out.writeByte((int) value);
+                    return;
+                } else {
+                    out.writeByte(((int) value & 0x7F) | 0x80);
+                    value >>>= 7;
+                }
+            }
+        }
+
+        public static long[] readVarLongArray(DataInputStream in) throws IOException {
+            final int size = in.readInt();
+            if (size == -1) return null;
+            final long[] values = new long[size];
+            for (int i = 0; i < values.length; i++) {
+                values[i] = readVarLong(in);
+            }
+            return values;
+        }
+
+        public static void writeVarLongArray(DataOutputStream out, long[] values, int size)
+                throws IOException {
+            if (values == null) {
+                out.writeInt(-1);
+                return;
+            }
+            if (size > values.length) {
+                throw new IllegalArgumentException("size larger than length");
+            }
+            out.writeInt(size);
+            for (int i = 0; i < size; i++) {
+                writeVarLong(out, values[i]);
+            }
+        }
+    }
+
+    /**
+     * Utility methods for interacting with {@link Parcel} structures, mostly
+     * dealing with writing partial arrays.
+     */
+    public static class ParcelUtils {
+        public static long[] readLongArray(Parcel in) {
+            final int size = in.readInt();
+            if (size == -1) return null;
+            final long[] values = new long[size];
+            for (int i = 0; i < values.length; i++) {
+                values[i] = in.readLong();
+            }
+            return values;
+        }
+
+        public static void writeLongArray(Parcel out, long[] values, int size) {
+            if (values == null) {
+                out.writeInt(-1);
+                return;
+            }
+            if (size > values.length) {
+                throw new IllegalArgumentException("size larger than length");
+            }
+            out.writeInt(size);
+            for (int i = 0; i < size; i++) {
+                out.writeLong(values[i]);
+            }
+        }
+    }
+
+}