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/*
* Copyright (C) 2007 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 libcore.util;
import java.util.Arrays;
import java.util.Date;
import java.util.TimeZone;
import libcore.io.BufferIterator;
/**
* Our concrete TimeZone implementation, backed by zoneinfo data.
*
* @hide - used to implement TimeZone
*/
public final class ZoneInfo extends TimeZone {
private static final long MILLISECONDS_PER_DAY = 24 * 60 * 60 * 1000;
private static final long MILLISECONDS_PER_400_YEARS =
MILLISECONDS_PER_DAY * (400 * 365 + 100 - 3);
private static final long UNIX_OFFSET = 62167219200000L;
private static final int[] NORMAL = new int[] {
0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334,
};
private static final int[] LEAP = new int[] {
0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335,
};
private int mRawOffset;
private final int mEarliestRawOffset;
private final boolean mUseDst;
private final int mDstSavings; // Implements TimeZone.getDSTSavings.
private final int[] mTransitions;
private final int[] mOffsets;
private final byte[] mTypes;
private final byte[] mIsDsts;
public static TimeZone makeTimeZone(String id, BufferIterator it) {
// Variable names beginning tzh_ correspond to those in "tzfile.h".
// Check tzh_magic.
if (it.readInt() != 0x545a6966) { // "TZif"
return null;
}
// Skip the uninteresting part of the header.
it.skip(28);
// Read the sizes of the arrays we're about to read.
int tzh_timecnt = it.readInt();
int tzh_typecnt = it.readInt();
it.skip(4); // Skip tzh_charcnt.
int[] transitions = new int[tzh_timecnt];
it.readIntArray(transitions, 0, transitions.length);
byte[] type = new byte[tzh_timecnt];
it.readByteArray(type, 0, type.length);
int[] gmtOffsets = new int[tzh_typecnt];
byte[] isDsts = new byte[tzh_typecnt];
for (int i = 0; i < tzh_typecnt; ++i) {
gmtOffsets[i] = it.readInt();
isDsts[i] = it.readByte();
// We skip the abbreviation index. This would let us provide historically-accurate
// time zone abbreviations (such as "AHST", "YST", and "AKST" for standard time in
// America/Anchorage in 1982, 1983, and 1984 respectively). ICU only knows the current
// names, though, so even if we did use this data to provide the correct abbreviations
// for en_US, we wouldn't be able to provide correct abbreviations for other locales,
// nor would we be able to provide correct long forms (such as "Yukon Standard Time")
// for any locale. (The RI doesn't do any better than us here either.)
it.skip(1);
}
return new ZoneInfo(id, transitions, type, gmtOffsets, isDsts);
}
private ZoneInfo(String name, int[] transitions, byte[] types, int[] gmtOffsets, byte[] isDsts) {
mTransitions = transitions;
mTypes = types;
mIsDsts = isDsts;
setID(name);
// Find the latest daylight and standard offsets (if any).
int lastStd = 0;
boolean haveStd = false;
int lastDst = 0;
boolean haveDst = false;
for (int i = mTransitions.length - 1; (!haveStd || !haveDst) && i >= 0; --i) {
int type = mTypes[i] & 0xff;
if (!haveStd && mIsDsts[type] == 0) {
haveStd = true;
lastStd = i;
}
if (!haveDst && mIsDsts[type] != 0) {
haveDst = true;
lastDst = i;
}
}
// Use the latest non-daylight offset (if any) as the raw offset.
if (lastStd >= mTypes.length) {
mRawOffset = gmtOffsets[0];
} else {
mRawOffset = gmtOffsets[mTypes[lastStd] & 0xff];
}
// Use the latest transition's pair of offsets to compute the DST savings.
// This isn't generally useful, but it's exposed by TimeZone.getDSTSavings.
if (lastDst >= mTypes.length) {
mDstSavings = 0;
} else {
mDstSavings = Math.abs(gmtOffsets[mTypes[lastStd] & 0xff] - gmtOffsets[mTypes[lastDst] & 0xff]) * 1000;
}
// Cache the oldest known raw offset, in case we're asked about times that predate our
// transition data.
int firstStd = -1;
for (int i = 0; i < mTransitions.length; ++i) {
if (mIsDsts[mTypes[i] & 0xff] == 0) {
firstStd = i;
break;
}
}
int earliestRawOffset = (firstStd != -1) ? gmtOffsets[mTypes[firstStd] & 0xff] : mRawOffset;
// Rather than keep offsets from UTC, we use offsets from local time, so the raw offset
// can be changed and automatically affect all the offsets.
mOffsets = gmtOffsets;
for (int i = 0; i < mOffsets.length; i++) {
mOffsets[i] -= mRawOffset;
}
// Is this zone still observing DST?
// We don't care if they've historically used it: most places have at least once.
// We want to know whether the last "schedule info" (the unix times in the mTransitions
// array) is in the future. If it is, DST is still relevant.
// See http://code.google.com/p/android/issues/detail?id=877.
// This test means that for somewhere like Morocco, which tried DST in 2009 but has
// no future plans (and thus no future schedule info) will report "true" from
// useDaylightTime at the start of 2009 but "false" at the end. This seems appropriate.
boolean usesDst = false;
long currentUnixTime = System.currentTimeMillis() / 1000;
if (mTransitions.length > 0) {
// (We're really dealing with uint32_t values, so long is most convenient in Java.)
long latestScheduleTime = ((long) mTransitions[mTransitions.length - 1]) & 0xffffffff;
if (currentUnixTime < latestScheduleTime) {
usesDst = true;
}
}
mUseDst = usesDst;
// tzdata uses seconds, but Java uses milliseconds.
mRawOffset *= 1000;
mEarliestRawOffset = earliestRawOffset * 1000;
}
@Override
public int getOffset(int era, int year, int month, int day, int dayOfWeek, int millis) {
// XXX This assumes Gregorian always; Calendar switches from
// Julian to Gregorian in 1582. What calendar system are the
// arguments supposed to come from?
long calc = (year / 400) * MILLISECONDS_PER_400_YEARS;
year %= 400;
calc += year * (365 * MILLISECONDS_PER_DAY);
calc += ((year + 3) / 4) * MILLISECONDS_PER_DAY;
if (year > 0) {
calc -= ((year - 1) / 100) * MILLISECONDS_PER_DAY;
}
boolean isLeap = (year == 0 || (year % 4 == 0 && year % 100 != 0));
int[] mlen = isLeap ? LEAP : NORMAL;
calc += mlen[month] * MILLISECONDS_PER_DAY;
calc += (day - 1) * MILLISECONDS_PER_DAY;
calc += millis;
calc -= mRawOffset;
calc -= UNIX_OFFSET;
return getOffset(calc);
}
@Override
public int getOffset(long when) {
int unix = (int) (when / 1000);
int transition = Arrays.binarySearch(mTransitions, unix);
if (transition < 0) {
transition = ~transition - 1;
if (transition < 0) {
// Assume that all times before our first transition correspond to the
// oldest-known non-daylight offset. The obvious alternative would be to
// use the current raw offset, but that seems like a greater leap of faith.
return mEarliestRawOffset;
}
}
return mRawOffset + mOffsets[mTypes[transition] & 0xff] * 1000;
}
@Override public boolean inDaylightTime(Date time) {
long when = time.getTime();
int unix = (int) (when / 1000);
int transition = Arrays.binarySearch(mTransitions, unix);
if (transition < 0) {
transition = ~transition - 1;
if (transition < 0) {
// Assume that all times before our first transition are non-daylight.
// Transition data tends to start with a transition to daylight, so just
// copying the first transition would assume the opposite.
// http://code.google.com/p/android/issues/detail?id=14395
return false;
}
}
return mIsDsts[mTypes[transition] & 0xff] == 1;
}
@Override public int getRawOffset() {
return mRawOffset;
}
@Override public void setRawOffset(int off) {
mRawOffset = off;
}
@Override public int getDSTSavings() {
return mUseDst ? mDstSavings: 0;
}
@Override public boolean useDaylightTime() {
return mUseDst;
}
@Override public boolean hasSameRules(TimeZone timeZone) {
if (!(timeZone instanceof ZoneInfo)) {
return false;
}
ZoneInfo other = (ZoneInfo) timeZone;
if (mUseDst != other.mUseDst) {
return false;
}
if (!mUseDst) {
return mRawOffset == other.mRawOffset;
}
return mRawOffset == other.mRawOffset
// Arrays.equals returns true if both arrays are null
&& Arrays.equals(mOffsets, other.mOffsets)
&& Arrays.equals(mIsDsts, other.mIsDsts)
&& Arrays.equals(mTypes, other.mTypes)
&& Arrays.equals(mTransitions, other.mTransitions);
}
@Override public boolean equals(Object obj) {
if (!(obj instanceof ZoneInfo)) {
return false;
}
ZoneInfo other = (ZoneInfo) obj;
return getID().equals(other.getID()) && hasSameRules(other);
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + getID().hashCode();
result = prime * result + Arrays.hashCode(mOffsets);
result = prime * result + Arrays.hashCode(mIsDsts);
result = prime * result + mRawOffset;
result = prime * result + Arrays.hashCode(mTransitions);
result = prime * result + Arrays.hashCode(mTypes);
result = prime * result + (mUseDst ? 1231 : 1237);
return result;
}
@Override
public String toString() {
return getClass().getName() + "[id=\"" + getID() + "\"" +
",mRawOffset=" + mRawOffset +
",mEarliestRawOffset=" + mEarliestRawOffset +
",mUseDst=" + mUseDst +
",mDstSavings=" + mDstSavings +
",transitions=" + mTransitions.length +
"]";
}
}
