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International Component for Unicode for Java (ICU4J) is a mature, widely used Java library
providing Unicode and Globalization support
// © 2018 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html#License
package com.ibm.icu.impl;
import java.util.Arrays;
import com.ibm.icu.util.ICUException;
import com.ibm.icu.util.TimeZone;
import com.ibm.icu.util.UResourceBundle;
import com.ibm.icu.util.UResourceBundleIterator;
/**
* EraRules represents calendar era rules specified
* in supplementalData/calendarData.
*
* @author Yoshito Umaoka
*/
public class EraRules {
private static final int MAX_ENCODED_START_YEAR = 32767;
private static final int MIN_ENCODED_START_YEAR = -32768;
public static final int MIN_ENCODED_START = encodeDate(MIN_ENCODED_START_YEAR, 1, 1);
private static final int YEAR_MASK = 0xFFFF0000;
private static final int MONTH_MASK = 0x0000FF00;
private static final int DAY_MASK = 0x000000FF;
private int[] startDates;
private int numEras;
private int currentEra;
private EraRules(int[] startDates, int numEras) {
this.startDates = startDates;
this.numEras = numEras;
initCurrentEra();
}
public static EraRules getInstance(CalType calType, boolean includeTentativeEra) {
UResourceBundle supplementalDataRes = UResourceBundle.getBundleInstance(ICUData.ICU_BASE_NAME,
"supplementalData", ICUResourceBundle.ICU_DATA_CLASS_LOADER);
UResourceBundle calendarDataRes = supplementalDataRes.get("calendarData");
UResourceBundle calendarTypeRes = calendarDataRes.get(calType.getId());
UResourceBundle erasRes = calendarTypeRes.get("eras");
int numEras = erasRes.getSize();
int firstTentativeIdx = Integer.MAX_VALUE; // first tentative era index
int[] startDates = new int[numEras];
UResourceBundleIterator itr = erasRes.getIterator();
while (itr.hasNext()) {
UResourceBundle eraRuleRes = itr.next();
String eraIdxStr = eraRuleRes.getKey();
int eraIdx = -1;
try {
eraIdx = Integer.parseInt(eraIdxStr);
} catch (NumberFormatException e) {
throw new ICUException("Invald era rule key:" + eraIdxStr + " in era rule data for " + calType.getId());
}
if (eraIdx < 0 || eraIdx >= numEras) {
throw new ICUException("Era rule key:" + eraIdxStr + " in era rule data for " + calType.getId()
+ " must be in range [0, " + (numEras - 1) + "]");
}
if (isSet(startDates[eraIdx])) {
throw new ICUException(
"Dupulicated era rule for rule key:" + eraIdxStr + " in era rule data for " + calType.getId());
}
boolean hasName = true;
boolean hasEnd = false;
UResourceBundleIterator ruleItr = eraRuleRes.getIterator();
while (ruleItr.hasNext()) {
UResourceBundle res = ruleItr.next();
String key = res.getKey();
if (key.equals("start")) {
int[] fields = res.getIntVector();
if (fields.length != 3 || !isValidRuleStartDate(fields[0], fields[1], fields[2])) {
throw new ICUException(
"Invalid era rule date data:" + Arrays.toString(fields) + " in era rule data for "
+ calType.getId());
}
startDates[eraIdx] = encodeDate(fields[0], fields[1], fields[2]);
} else if (key.equals("named")) {
String val = res.getString();
if (val.equals("false")) {
hasName = false;
}
} else if (key.equals("end")) {
hasEnd = true;
}
}
if (isSet(startDates[eraIdx])) {
if (hasEnd) {
// This implementation assumes either start or end is available, not both.
// For now, just ignore the end rule.
}
} else {
if (hasEnd) {
if (eraIdx != 0) {
// This implementation does not support end only rule for eras other than
// the first one.
throw new ICUException(
"Era data for " + eraIdxStr + " in era rule data for " + calType.getId()
+ " has only end rule.");
}
startDates[eraIdx] = MIN_ENCODED_START;
} else {
throw new ICUException("Missing era start/end rule date for key:" + eraIdxStr + " in era rule data for "
+ calType.getId());
}
}
if (hasName) {
if (eraIdx >= firstTentativeIdx) {
throw new ICUException(
"Non-tentative era(" + eraIdx + ") must be placed before the first tentative era");
}
} else {
if (eraIdx < firstTentativeIdx) {
firstTentativeIdx = eraIdx;
}
}
}
if (firstTentativeIdx < Integer.MAX_VALUE && !includeTentativeEra) {
return new EraRules(startDates, firstTentativeIdx);
}
return new EraRules(startDates, numEras);
}
/**
* Gets number of effective eras
* @return number of effective eras
*/
public int getNumberOfEras() {
return numEras;
}
/**
* Gets start date of an era
* @param eraIdx Era index
* @param fillIn Receives date fields if supplied. If null, or size of array
* is less than 3, then a new int[] will be newly allocated.
* @return An int array including values of year, month, day of month in this order.
* When an era has no start date, the result will be January 1st in year
* whose value is minimum integer.
*/
public int[] getStartDate(int eraIdx, int[] fillIn) {
if (eraIdx < 0 || eraIdx >= numEras) {
throw new IllegalArgumentException("eraIdx is out of range");
}
return decodeDate(startDates[eraIdx], fillIn);
}
/**
* Gets start year of an era
* @param eraIdx Era index
* @return The first year of an era. When a era has no start date, minimum integer
* value is returned.
*/
public int getStartYear(int eraIdx) {
if (eraIdx < 0 || eraIdx >= numEras) {
throw new IllegalArgumentException("eraIdx is out of range");
}
int[] fields = decodeDate(startDates[eraIdx], null);
return fields[0];
}
/**
* Returns era index for the specified year/month/day.
* @param year Year
* @param month Month (1-base)
* @param day Day of month
* @return era index (or 0, when the specified date is before the first era)
*/
public int getEraIndex(int year, int month, int day) {
if (month < 1 || month > 12 || day < 1 || day > 31) {
throw new IllegalArgumentException("Illegal date - year:" + year + "month:" + month + "day:" + day);
}
int high = numEras; // last index + 1
int low;
// Short circuit for recent years. Most modern computations will
// occur in the last few eras.
if (compareEncodedDateWithYMD(startDates[getCurrentEraIndex()], year, month, day) <= 0) {
low = getCurrentEraIndex();
} else {
low = 0;
}
// Do binary search
while (low < high - 1) {
int i = (low + high) / 2;
if (compareEncodedDateWithYMD(startDates[i], year, month, day) <= 0) {
low = i;
} else {
high = i;
}
}
return low;
}
/**
* Gets the current era index. This is calculated only once for an instance of
* EraRules. The current era calculation is based on the default time zone at
* the time of instantiation.
*
* @return era index of current era (or 0, when current date is before the first era)
*/
public int getCurrentEraIndex() {
return currentEra;
}
private void initCurrentEra() {
long localMillis = System.currentTimeMillis();
TimeZone zone = TimeZone.getDefault();
localMillis += zone.getOffset(localMillis);
int[] fields = Grego.timeToFields(localMillis, null);
int currentEncodedDate = encodeDate(fields[0], fields[1] + 1 /* changes to 1-base */, fields[2]);
int eraIdx = numEras - 1;
while (eraIdx > 0) {
if (currentEncodedDate >= startDates[eraIdx]) {
break;
}
eraIdx--;
}
// Note: current era could be before the first era.
// In this case, this implementation returns the first era index (0).
currentEra = eraIdx;
}
//
// private methods
//
private static boolean isSet(int startDate) {
return startDate != 0;
}
private static boolean isValidRuleStartDate(int year, int month, int day) {
return year >= MIN_ENCODED_START_YEAR && year <= MAX_ENCODED_START_YEAR
&& month >= 1 && month <= 12 && day >= 1 && day <= 31;
}
/**
* Encode year/month/date to a single integer.
* year is high 16 bits (-32768 to 32767), month is
* next 8 bits and day of month is last 8 bits.
*
* @param year year
* @param month month (1-base)
* @param day day of month
* @return an encoded date.
*/
private static int encodeDate(int year, int month, int day) {
return year << 16 | month << 8 | day;
}
private static int[] decodeDate(int encodedDate, int[] fillIn) {
int year, month, day;
if (encodedDate == MIN_ENCODED_START) {
year = Integer.MIN_VALUE;
month = 1;
day = 1;
} else {
year = (encodedDate & YEAR_MASK) >> 16;
month = (encodedDate & MONTH_MASK) >> 8;
day = encodedDate & DAY_MASK;
}
if (fillIn != null && fillIn.length >= 3) {
fillIn[0] = year;
fillIn[1] = month;
fillIn[2] = day;
return fillIn;
}
int[] result = {year, month, day};
return result;
}
/**
* Compare an encoded date with another date specified by year/month/day.
* @param encoded An encoded date
* @param year Year of another date
* @param month Month of another date
* @param day Day of another date
* @return -1 when encoded date is earlier, 0 when two dates are same,
* and 1 when encoded date is later.
*/
private static int compareEncodedDateWithYMD(int encoded, int year, int month, int day) {
if (year < MIN_ENCODED_START_YEAR) {
if (encoded == MIN_ENCODED_START) {
if (year > Integer.MIN_VALUE || month > 1 || day > 1) {
return -1;
}
return 0;
} else {
return 1;
}
} else if (year > MAX_ENCODED_START_YEAR) {
return -1;
} else {
int tmp = encodeDate(year, month, day);
if (encoded < tmp) {
return -1;
} else if (encoded == tmp) {
return 0;
} else {
return 1;
}
}
}
}