ICU-23102 Remove unused code

Author: FrankYFTang

icu4c/source/i18n/calendar.cpp

@@ -1529,9 +1529,15 @@ void Calendar::computeGregorianFields(int32_t julianDay, UErrorCode& ec) {
         ec = U_ILLEGAL_ARGUMENT_ERROR;
         return;
     }
+    int8_t dayOfWeek;
     Grego::dayToFields(julianDay, fGregorianYear, fGregorianMonth,
                        fGregorianDayOfMonth,
+                       dayOfWeek,
                        fGregorianDayOfYear, ec);
+    if (U_FAILURE(ec)) {
+        return;
+    }
+    internalSet(UCAL_DAY_OF_WEEK, dayOfWeek);
 }
 
 /**
@@ -1560,8 +1566,7 @@ void Calendar::computeWeekFields(UErrorCode &ec) {
     }
 
     // Compute day of week: JD 0 = Monday
-    int32_t dayOfWeek = julianDayToDayOfWeek(fFields[UCAL_JULIAN_DAY]);
-    internalSet(UCAL_DAY_OF_WEEK, dayOfWeek);
+    int32_t dayOfWeek = fFields[UCAL_DAY_OF_WEEK];
     int32_t firstDayOfWeek = getFirstDayOfWeek();
     // Calculate 1-based localized day of week
     int32_t dowLocal = dayOfWeek - firstDayOfWeek + 1;

icu4c/source/i18n/gregoimp.cpp

@@ -176,18 +176,6 @@ int32_t Grego::dayToYear(int32_t day, int16_t& doy, UErrorCode& status) {
     return year;
 }
 
-void Grego::dayToFields(int32_t day, int32_t& year, int8_t& month,
-                        int8_t& dom, int8_t& dow, UErrorCode& status) {
-    int16_t unusedDOY;
-    dayToFields(day, year, month, dom, dow, unusedDOY, status);
-}
-
-void Grego::dayToFields(int32_t day, int32_t& year, int8_t& month,
-                        int8_t& dom, int16_t& doy, UErrorCode& status) {
-    int8_t unusedDOW;
-    dayToFields(day, year, month, dom, unusedDOW, doy, status);
-}
-
 void Grego::timeToFields(UDate time, int32_t& year, int8_t& month,
                         int8_t& dom, int32_t& mid, UErrorCode& status) {
     int8_t unusedDOW;

icu4c/source/i18n/gregoimp.h

@@ -213,32 +213,6 @@ class Grego {
     static void dayToFields(int32_t day, int32_t& year, int8_t& month,
                             int8_t& dom, int8_t& dow, int16_t& doy, UErrorCode& status);
 
-    /**
-     * Convert a 1970-epoch day number to proleptic Gregorian year,
-     * month, day-of-month, and day-of-week.
-     * @param day 1970-epoch day
-     * @param year output parameter to receive year
-     * @param month output parameter to receive month (0-based, 0==Jan)
-     * @param dom output parameter to receive day-of-month (1-based)
-     * @param doy output parameter to receive day-of-year (1-based)
-     * @param status error code.
-     */
-    static void dayToFields(int32_t day, int32_t& year, int8_t& month,
-                            int8_t& dom, int16_t& doy, UErrorCode& status);
-
-    /**
-     * Convert a 1970-epoch day number to proleptic Gregorian year,
-     * month, day-of-month, and day-of-week.
-     * @param day 1970-epoch day
-     * @param year output parameter to receive year
-     * @param month output parameter to receive month (0-based, 0==Jan)
-     * @param dom output parameter to receive day-of-month (1-based)
-     * @param dow output parameter to receive day-of-week (1-based, 1==Sun)
-     * @param status error code.
-     */
-    static void dayToFields(int32_t day, int32_t& year, int8_t& month,
-                            int8_t& dom, int8_t& dow, UErrorCode& status);
-
     /**
      * Convert a 1970-epoch day number to proleptic Gregorian year.
      * @param day 1970-epoch day

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

@@ -20,6 +20,7 @@
 
 import com.ibm.icu.impl.CalType;
 import com.ibm.icu.impl.CalendarUtil;
+import com.ibm.icu.impl.Grego;
 import com.ibm.icu.impl.ICUCache;
 import com.ibm.icu.impl.ICUData;
 import com.ibm.icu.impl.ICUResourceBundle;
@@ -5322,42 +5323,11 @@ private final void computeGregorianAndDOWFields(int julianDay) {
      * @stable ICU 2.0
      */
     protected final void computeGregorianFields(int julianDay) {
-        int year, month, dayOfMonth, dayOfYear;
-
-        // The Gregorian epoch day is zero for Monday January 1, year 1.
-        long gregorianEpochDay = julianDay - JAN_1_1_JULIAN_DAY;
-
-        // Here we convert from the day number to the multiple radix
-        // representation.  We use 400-year, 100-year, and 4-year cycles.
-        // For example, the 4-year cycle has 4 years + 1 leap day; giving
-        // 1461 == 365*4 + 1 days.
-        int[] rem = new int[1];
-        int n400 = floorDivide(gregorianEpochDay, 146097, rem); // 400-year cycle length
-        int n100 = floorDivide(rem[0], 36524, rem); // 100-year cycle length
-        int n4 = floorDivide(rem[0], 1461, rem); // 4-year cycle length
-        int n1 = floorDivide(rem[0], 365, rem);
-        year = 400*n400 + 100*n100 + 4*n4 + n1;
-        dayOfYear = rem[0]; // zero-based day of year
-        if (n100 == 4 || n1 == 4) {
-            dayOfYear = 365; // Dec 31 at end of 4- or 400-yr cycle
-        } else {
-            ++year;
-        }
-
-        boolean isLeap = ((year&0x3) == 0) && // equiv. to (year%4 == 0)
-                (year%100 != 0 || year%400 == 0);
-
-        int correction = 0;
-        int march1 = isLeap ? 60 : 59; // zero-based DOY for March 1
-        if (dayOfYear >= march1) correction = isLeap ? 1 : 2;
-        month = (12 * (dayOfYear + correction) + 6) / 367; // zero-based month
-        dayOfMonth = dayOfYear -
-                GREGORIAN_MONTH_COUNT[month][isLeap?3:2] + 1; // one-based DOM
-
-        gregorianYear = year;
-        gregorianMonth = month; // 0-based already
-        gregorianDayOfMonth = dayOfMonth; // 1-based already
-        gregorianDayOfYear = dayOfYear + 1; // Convert from 0-based to 1-based
+        int[] gregorian = Grego.dayToFields(julianDay - EPOCH_JULIAN_DAY, null);
+        gregorianYear = gregorian[0];
+        gregorianMonth = gregorian[1];
+        gregorianDayOfMonth = gregorian[2];
+        gregorianDayOfYear = gregorian[4];
     }
 
     /**