ICU-23167 Change Ethiopian Amete Alem epoch

See #3602

Author: FrankYFTang

icu4c/source/i18n/ethpccal.cpp

@@ -22,7 +22,7 @@ U_NAMESPACE_BEGIN
 UOBJECT_DEFINE_RTTI_IMPLEMENTATION(EthiopicCalendar)
 UOBJECT_DEFINE_RTTI_IMPLEMENTATION(EthiopicAmeteAlemCalendar)
 
-//static const int32_t JD_EPOCH_OFFSET_AMETE_ALEM = -285019;
+static const int32_t JD_EPOCH_OFFSET_AMETE_ALEM = -285019;
 static const int32_t JD_EPOCH_OFFSET_AMETE_MIHRET = 1723856;
 static const int32_t AMETE_MIHRET_DELTA = 5500; // 5501 - 1 (Amete Alem 5501 = Amete Mihret 1)
 
@@ -141,21 +141,22 @@ EthiopicAmeteAlemCalendar::handleGetExtendedYear(UErrorCode& status)
     if (newerField(UCAL_EXTENDED_YEAR, UCAL_YEAR) == UCAL_EXTENDED_YEAR) {
         return internalGet(UCAL_EXTENDED_YEAR, 1); // Default to year 1
     }
-    // Default to year 1 of Amelete Mihret
-    int32_t year = internalGet(UCAL_YEAR, 1 + AMETE_MIHRET_DELTA);
-    if (uprv_add32_overflow(year, -AMETE_MIHRET_DELTA, &year)) {
-        status = U_ILLEGAL_ARGUMENT_ERROR;
-        return 0;
-    }
-    return year;
+    // Default to year 1
+    return internalGet(UCAL_YEAR, 1);
+}
+
+int32_t
+EthiopicAmeteAlemCalendar::getJDEpochOffset() const
+{
+    return JD_EPOCH_OFFSET_AMETE_ALEM;
 }
 
 int32_t EthiopicAmeteAlemCalendar::extendedYearToEra(int32_t /* extendedYear */) const {
     return AMETE_ALEM;
 }
 
 int32_t EthiopicAmeteAlemCalendar::extendedYearToYear(int32_t extendedYear) const {
-    return extendedYear + AMETE_MIHRET_DELTA;
+    return extendedYear;
 }
 
 
@@ -168,17 +169,6 @@ EthiopicAmeteAlemCalendar::handleGetLimit(UCalendarDateFields field, ELimitType
     return EthiopicCalendar::handleGetLimit(field, limitType);
 }
 
-int32_t
-EthiopicAmeteAlemCalendar::defaultCenturyStartYear() const
-{
-    return EthiopicCalendar::defaultCenturyStartYear() + AMETE_MIHRET_DELTA;
-}
-
-
-int32_t EthiopicAmeteAlemCalendar::getRelatedYearDifference() const {
-    constexpr int32_t kEthiopicAmeteAlemCalendarRelatedYearDifference = -5492;
-    return kEthiopicAmeteAlemCalendarRelatedYearDifference;
-}
 U_NAMESPACE_END
 
 #endif

icu4c/source/i18n/ethpccal.h

@@ -304,11 +304,6 @@ class EthiopicAmeteAlemCalendar : public EthiopicCalendar {
     // Calendar framework
     //-------------------------------------------------------------------------
 
-    /**
-     * @internal
-     */
-    int32_t getRelatedYearDifference() const override;
-
     /**
      * Return the extended year defined by the current fields.
      * This calendar use only AMETE_ALEM for the era.
@@ -325,11 +320,12 @@ class EthiopicAmeteAlemCalendar : public EthiopicCalendar {
      * @internal
      */
     virtual int32_t handleGetLimit(UCalendarDateFields field, ELimitType limitType) const override;
+
     /**
-     * Returns the year in which the default century begins
+     * Return the date offset from Julian
      * @internal
      */
-    virtual int32_t defaultCenturyStartYear() const override;
+    int32_t getJDEpochOffset() const override;
 
     /**
      * Compute the era from extended year.

icu4c/source/test/intltest/caltest.cpp

@@ -2994,7 +2994,7 @@ void CalendarTest::TestBasicConversionEthiopicAmeteAlem() {
     AsssertCalendarFieldValue(
         cal.getAlias(), test_time, "ethiopic-amete-alem",
         0, 7515, 1, 8, 4, 22, 52, 3, 4, 0, 4, 4, 44, 51,
-        323, 0, 0, 2015, 3, 2015, 2459885, 17091323, 0);
+        323, 0, 0, 7515, 3, 7515, 2459885, 17091323, 0);
 }
 
 

icu4c/source/test/intltest/dtfmttst.cpp

@@ -4896,6 +4896,24 @@ void DateFormatTest::TestCreateInstanceForSkeleton() {
     result.remove();
     fmt->format(date(98, 5-1, 25), result, pos);
     assertEquals("format yMd", "5/25/1998", result);
+
+    UnicodeString result2;
+    fmt.adoptInstead(DateFormat::createInstanceForSkeleton(
+            "yMd", "en-u-ca-ethiopic-amete-alem", status));
+    if (!assertSuccess("Create with pattern yMd", status)) {
+        return;
+    }
+    fmt->format(date(98, 5-1, 25), result2, pos);
+    assertEquals("format yMd", "9/17/7490 ERA0", result2);
+
+    fmt.adoptInstead(DateFormat::createInstanceForSkeleton(
+            "uMd", "en-u-ca-ethiopic-amete-alem", status));
+    if (!assertSuccess("Create with pattern uMd", status)) {
+        return;
+    }
+    result.remove();
+    fmt->format(date(98, 5-1, 25), result, pos);
+    assertEquals("format uMd", result2, result);
 }
 
 void DateFormatTest::TestCreateInstanceForSkeletonDefault() {

icu4j/main/common_tests/src/test/java/com/ibm/icu/dev/test/format/DateFormatTest.java

@@ -5576,6 +5576,17 @@ public void test20739_MillisecondsWithoutSeconds() {
         }
     }
 
+    @Test
+    public void testExtendedYear() {
+        ULocale locale = new ULocale("en-u-ca-ethiopic-amete-alem");
+        DateFormat fmt = DateFormat.getInstanceForSkeleton("yMd", locale);
+        DateFormat fmt2 = DateFormat.getInstanceForSkeleton("uMd", locale);
+        String result = fmt.format(new Date(98, 5-1, 25));
+        String result2 = fmt2.format(new Date(98, 5-1, 25));
+        assertEquals("Format", "9/17/7490 ERA0", result);
+        assertEquals("Format", result, result2);
+    }
+
     @Test
     public void test20741_ABFields() {
         String [] skeletons = {"EEEEEBBBBB", "EEEEEbbbbb"};

icu4j/main/core/src/main/java/com/ibm/icu/util/EthiopicCalendar.java

@@ -128,7 +128,7 @@ public final class EthiopicCalendar extends CECalendar
     // Julian Days relative to the
     // \u12d3\u1218\u1270\u1361\u121d\u1215\u1228\u1275 epoch
     // Note: we no longer use this constant
-    //private static final int JD_EPOCH_OFFSET_AMETE_ALEM = -285019;
+    private static final int JD_EPOCH_OFFSET_AMETE_ALEM = -285019;
 
     // Julian Days relative to the
     // \u12d3\u1218\u1270\u1361\u12d3\u1208\u121d epoch
@@ -306,8 +306,7 @@ protected int handleGetExtendedYear() {
         if (newerField(EXTENDED_YEAR, YEAR) == EXTENDED_YEAR) {
             eyear = internalGet(EXTENDED_YEAR, 1); // Default to year 1
         } else if (isAmeteAlemEra()){
-            eyear = internalGet(YEAR, 1 + AMETE_MIHRET_DELTA)
-                    - AMETE_MIHRET_DELTA; // Default to year 1 of Amelete Mihret
+            eyear = internalGet(YEAR, 1); // Default to year 1
         } else {
             // The year defaults to the epoch start, the era to AMETE_MIHRET
             int era = internalGet(ERA, AMETE_MIHRET);
@@ -344,7 +343,7 @@ protected int extendedYearToEra(int eyear) {
     @Override
     protected int extendedYearToYear(int eyear) {
         if (isAmeteAlemEra()) {
-            return eyear + AMETE_MIHRET_DELTA;
+            return eyear;
         } else {
             return (eyear <= 0) ? eyear + AMETE_MIHRET_DELTA : eyear;
         }
@@ -372,7 +371,7 @@ protected int handleGetLimit(int field, int limitType) {
     @Override
     @Deprecated
     protected int getJDEpochOffset() {
-        return JD_EPOCH_OFFSET_AMETE_MIHRET;
+        return isAmeteAlemEra() ? JD_EPOCH_OFFSET_AMETE_ALEM : JD_EPOCH_OFFSET_AMETE_MIHRET;
     }
 
     /**
@@ -393,8 +392,6 @@ public static int EthiopicToJD(long year, int month, int date) {
     }
 
 
-    private static final int ETHIOPIC_AMETE_ALEM_CALENDAR_RELATED_YEAR_DIFFERENCE = -5492;
-
     private static final int ETHIOPIC_CALENDAR_RELATED_YEAR_DIFFERENCE = 8;
 
     /**
@@ -403,9 +400,7 @@ public static int EthiopicToJD(long year, int month, int date) {
      */
     @Deprecated
     protected final int getRelatedYearDifference() {
-        return isAmeteAlemEra() ?
-            ETHIOPIC_AMETE_ALEM_CALENDAR_RELATED_YEAR_DIFFERENCE :
-            ETHIOPIC_CALENDAR_RELATED_YEAR_DIFFERENCE;
+        return ETHIOPIC_CALENDAR_RELATED_YEAR_DIFFERENCE;
     }
 
     /**