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/*
* Copyright (C) 2006 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 android.util;
import android.content.res.Resources;
import android.content.res.XmlResourceParser;
import org.apache.harmony.luni.internal.util.ZoneInfoDB;
import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.TimeZone;
import java.util.Date;
import com.android.internal.util.XmlUtils;
/**
* A class containing utility methods related to time zones.
*/
public class TimeUtils {
private static final String TAG = "TimeUtils";
/**
* Tries to return a time zone that would have had the specified offset
* and DST value at the specified moment in the specified country.
* Returns null if no suitable zone could be found.
*/
public static TimeZone getTimeZone(int offset, boolean dst, long when, String country) {
if (country == null) {
return null;
}
TimeZone best = null;
Resources r = Resources.getSystem();
XmlResourceParser parser = r.getXml(com.android.internal.R.xml.time_zones_by_country);
Date d = new Date(when);
TimeZone current = TimeZone.getDefault();
String currentName = current.getID();
int currentOffset = current.getOffset(when);
boolean currentDst = current.inDaylightTime(d);
try {
XmlUtils.beginDocument(parser, "timezones");
while (true) {
XmlUtils.nextElement(parser);
String element = parser.getName();
if (element == null || !(element.equals("timezone"))) {
break;
}
String code = parser.getAttributeValue(null, "code");
if (country.equals(code)) {
if (parser.next() == XmlPullParser.TEXT) {
String maybe = parser.getText();
// If the current time zone is from the right country
// and meets the other known properties, keep it
// instead of changing to another one.
if (maybe.equals(currentName)) {
if (currentOffset == offset && currentDst == dst) {
return current;
}
}
// Otherwise, take the first zone from the right
// country that has the correct current offset and DST.
// (Keep iterating instead of returning in case we
// haven't encountered the current time zone yet.)
if (best == null) {
TimeZone tz = TimeZone.getTimeZone(maybe);
if (tz.getOffset(when) == offset &&
tz.inDaylightTime(d) == dst) {
best = tz;
}
}
}
}
}
} catch (XmlPullParserException e) {
Log.e(TAG, "Got exception while getting preferred time zone.", e);
} catch (IOException e) {
Log.e(TAG, "Got exception while getting preferred time zone.", e);
} finally {
parser.close();
}
return best;
}
/**
* Returns a String indicating the version of the time zone database currently
* in use. The format of the string is dependent on the underlying time zone
* database implementation, but will typically contain the year in which the database
* was updated plus a letter from a to z indicating changes made within that year.
*
* <p>Time zone database updates should be expected to occur periodically due to
* political and legal changes that cannot be anticipated in advance. Therefore,
* when computing the UTC time for a future event, applications should be aware that
* the results may differ following a time zone database update. This method allows
* applications to detect that a database change has occurred, and to recalculate any
* cached times accordingly.
*
* <p>The time zone database may be assumed to change only when the device runtime
* is restarted. Therefore, it is not necessary to re-query the database version
* during the lifetime of an activity.
*/
public static String getTimeZoneDatabaseVersion() {
return ZoneInfoDB.getVersion();
}
private static final int SECONDS_PER_MINUTE = 60;
private static final int SECONDS_PER_HOUR = 60 * 60;
private static final int SECONDS_PER_DAY = 24 * 60 * 60;
/** @hide Just for debugging; not internationalized. */
public static void formatDuration(long duration, StringBuilder builder) {
if (duration == 0) {
builder.append("0");
return;
}
if (duration > 0) {
builder.append("+");
} else {
builder.append("-");
duration = -duration;
}
int millis = (int)(duration%1000);
int seconds = (int) Math.floor(duration / 1000);
int days = 0, hours = 0, minutes = 0;
if (seconds > SECONDS_PER_DAY) {
days = seconds / SECONDS_PER_DAY;
seconds -= days * SECONDS_PER_DAY;
}
if (seconds > SECONDS_PER_HOUR) {
hours = seconds / SECONDS_PER_HOUR;
seconds -= hours * SECONDS_PER_HOUR;
}
if (seconds > SECONDS_PER_MINUTE) {
minutes = seconds / SECONDS_PER_MINUTE;
seconds -= minutes * SECONDS_PER_MINUTE;
}
boolean doall = false;
if (days > 0) {
builder.append(days);
builder.append('d');
doall = true;
}
if (doall || hours > 0) {
builder.append(hours);
builder.append('h');
doall = true;
}
if (doall || minutes > 0) {
builder.append(minutes);
builder.append('m');
doall = true;
}
if (doall || seconds > 0) {
builder.append(seconds);
builder.append('s');
doall = true;
}
builder.append(millis);
builder.append("ms");
}
/** @hide Just for debugging; not internationalized. */
public static void formatDuration(long duration, PrintWriter pw) {
if (duration == 0) {
pw.print("0");
return;
}
if (duration > 0) {
pw.print("+");
} else {
pw.print("-");
duration = -duration;
}
int millis = (int)(duration%1000);
int seconds = (int) Math.floor(duration / 1000);
int days = 0, hours = 0, minutes = 0;
if (seconds > SECONDS_PER_DAY) {
days = seconds / SECONDS_PER_DAY;
seconds -= days * SECONDS_PER_DAY;
}
if (seconds > SECONDS_PER_HOUR) {
hours = seconds / SECONDS_PER_HOUR;
seconds -= hours * SECONDS_PER_HOUR;
}
if (seconds > SECONDS_PER_MINUTE) {
minutes = seconds / SECONDS_PER_MINUTE;
seconds -= minutes * SECONDS_PER_MINUTE;
}
boolean doall = false;
if (days > 0) {
pw.print(days);
pw.print('d');
doall = true;
}
if (doall || hours > 0) {
pw.print(hours);
pw.print('h');
doall = true;
}
if (doall || minutes > 0) {
pw.print(minutes);
pw.print('m');
doall = true;
}
if (doall || seconds > 0) {
pw.print(seconds);
pw.print('s');
doall = true;
}
pw.print(millis);
pw.print("ms");
}
/** @hide Just for debugging; not internationalized. */
public static void formatDuration(long time, long now, PrintWriter pw) {
if (time == 0) {
pw.print("--");
return;
}
formatDuration(time-now, pw);
}
}