From 841e88bc8cc3c470f7743f6557beb98814b1aea3 Mon Sep 17 00:00:00 2001
From: Frank Tang <ftang@chromium.org>
Date: Mon, 23 Dec 2024 14:15:18 -0800
Subject: [PATCH] ICU-22991 Remove unused private fIsSet

This field is removed in Java 24 years ago. Save 24 bytes per Calendar
object.
---
 icu4c/source/i18n/calendar.cpp       | 8 --------
 icu4c/source/i18n/unicode/calendar.h | 7 -------
 2 files changed, 15 deletions(-)

diff --git a/icu4c/source/i18n/calendar.cpp b/icu4c/source/i18n/calendar.cpp
index 637e7f84c40d..ca3de520c8f2 100644
--- a/icu4c/source/i18n/calendar.cpp
+++ b/icu4c/source/i18n/calendar.cpp
@@ -806,7 +806,6 @@ Calendar::operator=(const Calendar &right)
 {
     if (this != &right) {
         uprv_arrayCopy(right.fFields, fFields, UCAL_FIELD_COUNT);
-        uprv_arrayCopy(right.fIsSet, fIsSet, UCAL_FIELD_COUNT);
         uprv_arrayCopy(right.fStamp, fStamp, UCAL_FIELD_COUNT);
         fTime                    = right.fTime;
         fIsTimeSet               = right.fIsTimeSet;
@@ -1170,7 +1169,6 @@ Calendar::setTimeInMillis( double millis, UErrorCode& status ) {
     for (int32_t i=0; i<UCAL_FIELD_COUNT; ++i) {
         fFields[i]     = 0;
         fStamp[i]     = kUnset;
-        fIsSet[i]     = false;
     }
 
 
@@ -1213,7 +1211,6 @@ Calendar::set(UCalendarDateFields field, int32_t value)
         recalculateStamp();
     }
     fStamp[field]     = fNextStamp++;
-    fIsSet[field]     = true; // Remove later
     fIsTimeSet = fAreFieldsSet = fAreFieldsVirtuallySet = false;
 }
 
@@ -1273,7 +1270,6 @@ Calendar::clear()
     for (int32_t i=0; i<UCAL_FIELD_COUNT; ++i) {
         fFields[i]     = 0; // Must do this; other code depends on it
         fStamp[i]     = kUnset;
-        fIsSet[i]     = false; // Remove later
     }
     fIsTimeSet = fAreFieldsSet = fAreAllFieldsSet = fAreFieldsVirtuallySet = false;
     // fTime is not 'cleared' - may be used if no fields are set.
@@ -1296,12 +1292,10 @@ Calendar::clear(UCalendarDateFields field)
     if (field == UCAL_MONTH) {
         fFields[UCAL_ORDINAL_MONTH]         = 0;
         fStamp[UCAL_ORDINAL_MONTH]         = kUnset;
-        fIsSet[UCAL_ORDINAL_MONTH]         = false; // Remove later
     }
     if (field == UCAL_ORDINAL_MONTH) {
         fFields[UCAL_MONTH]         = 0;
         fStamp[UCAL_MONTH]         = kUnset;
-        fIsSet[UCAL_MONTH]         = false; // Remove later
     }
     fIsTimeSet = fAreFieldsSet = fAreAllFieldsSet = fAreFieldsVirtuallySet = false;
 }
@@ -1434,10 +1428,8 @@ void Calendar::computeFields(UErrorCode &ec)
     for (int32_t i=0; i<UCAL_FIELD_COUNT; ++i) {
         if ((mask & 1) == 0) {
             fStamp[i] = kInternallySet;
-            fIsSet[i] = true; // Remove later
         } else {
             fStamp[i] = kUnset;
-            fIsSet[i] = false; // Remove later
         }
         mask >>= 1;
     }
diff --git a/icu4c/source/i18n/unicode/calendar.h b/icu4c/source/i18n/unicode/calendar.h
index b965ca381e87..1d2104be607d 100644
--- a/icu4c/source/i18n/unicode/calendar.h
+++ b/icu4c/source/i18n/unicode/calendar.h
@@ -1937,12 +1937,6 @@ class U_I18N_API Calendar : public UObject {
      */
     int32_t     fFields[UCAL_FIELD_COUNT];
 
-private:
-    /**
-     * The flags which tell if a specified time field for the calendar is set.
-     */
-    UBool      fIsSet[UCAL_FIELD_COUNT];
-
 protected:
     /** Special values of stamp[]
      * @stable ICU 2.0
@@ -2552,7 +2546,6 @@ Calendar::internalSet(UCalendarDateFields field, int32_t value)
 {
     fFields[field] = value;
     fStamp[field] = kInternallySet;
-    fIsSet[field]     = true; // Remove later
 }
 
 /**