Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 595 insertions, 0 deletions

diff --git a/intl/icu/source/i18n/reldtfmt.cpp b/intl/icu/source/i18n/reldtfmt.cpp
new file mode 100644
index 0000000000..0c836a0b79
--- /dev/null
+++ b/intl/icu/source/i18n/reldtfmt.cpp
@@ -0,0 +1,595 @@
+// © 2016 and later: Unicode, Inc. and others.
+// License & terms of use: http://www.unicode.org/copyright.html
+/*
+*******************************************************************************
+* Copyright (C) 2007-2016, International Business Machines Corporation and
+* others. All Rights Reserved.
+*******************************************************************************
+*/
+
+#include "unicode/utypes.h"
+
+#if !UCONFIG_NO_FORMATTING
+
+#include <stdlib.h>
+
+#include "unicode/datefmt.h"
+#include "unicode/reldatefmt.h"
+#include "unicode/simpleformatter.h"
+#include "unicode/smpdtfmt.h"
+#include "unicode/udisplaycontext.h"
+#include "unicode/uchar.h"
+#include "unicode/brkiter.h"
+#include "unicode/ucasemap.h"
+#include "reldtfmt.h"
+#include "cmemory.h"
+#include "uresimp.h"
+
+U_NAMESPACE_BEGIN
+
+
+/**
+ * An array of URelativeString structs is used to store the resource data loaded out of the bundle.
+ */
+struct URelativeString {
+    int32_t offset;         /** offset of this item, such as, the relative date **/
+    int32_t len;            /** length of the string **/
+    const char16_t* string;    /** string, or nullptr if not set **/
+};
+
+UOBJECT_DEFINE_RTTI_IMPLEMENTATION(RelativeDateFormat)
+
+RelativeDateFormat::RelativeDateFormat(const RelativeDateFormat& other) :
+ DateFormat(other), fDateTimeFormatter(nullptr), fDatePattern(other.fDatePattern),
+ fTimePattern(other.fTimePattern), fCombinedFormat(nullptr),
+ fDateStyle(other.fDateStyle), fLocale(other.fLocale),
+ fDatesLen(other.fDatesLen), fDates(nullptr),
+ fCombinedHasDateAtStart(other.fCombinedHasDateAtStart),
+ fCapitalizationInfoSet(other.fCapitalizationInfoSet),
+ fCapitalizationOfRelativeUnitsForUIListMenu(other.fCapitalizationOfRelativeUnitsForUIListMenu),
+ fCapitalizationOfRelativeUnitsForStandAlone(other.fCapitalizationOfRelativeUnitsForStandAlone),
+ fCapitalizationBrkIter(nullptr)
+{
+    if(other.fDateTimeFormatter != nullptr) {
+        fDateTimeFormatter = other.fDateTimeFormatter->clone();
+    }
+    if(other.fCombinedFormat != nullptr) {
+        fCombinedFormat = new SimpleFormatter(*other.fCombinedFormat);
+    }
+    if (fDatesLen > 0) {
+        fDates = (URelativeString*) uprv_malloc(sizeof(fDates[0])*(size_t)fDatesLen);
+        uprv_memcpy(fDates, other.fDates, sizeof(fDates[0])*(size_t)fDatesLen);
+    }
+#if !UCONFIG_NO_BREAK_ITERATION
+    if (other.fCapitalizationBrkIter != nullptr) {
+        fCapitalizationBrkIter = (other.fCapitalizationBrkIter)->clone();
+    }
+#endif
+}
+
+RelativeDateFormat::RelativeDateFormat( UDateFormatStyle timeStyle, UDateFormatStyle dateStyle,
+                                        const Locale& locale, UErrorCode& status) :
+ DateFormat(), fDateTimeFormatter(nullptr), fDatePattern(), fTimePattern(), fCombinedFormat(nullptr),
+ fDateStyle(dateStyle), fLocale(locale), fDatesLen(0), fDates(nullptr),
+ fCombinedHasDateAtStart(false), fCapitalizationInfoSet(false),
+ fCapitalizationOfRelativeUnitsForUIListMenu(false), fCapitalizationOfRelativeUnitsForStandAlone(false),
+ fCapitalizationBrkIter(nullptr)
+{
+    if(U_FAILURE(status) ) {
+        return;
+    }
+
+    if (timeStyle < UDAT_NONE || timeStyle > UDAT_SHORT) {
+        // don't support other time styles (e.g. relative styles), for now
+        status = U_ILLEGAL_ARGUMENT_ERROR;
+        return;
+    }
+    UDateFormatStyle baseDateStyle = (dateStyle > UDAT_SHORT)? (UDateFormatStyle)(dateStyle & ~UDAT_RELATIVE): dateStyle;
+    DateFormat * df;
+    // Get fDateTimeFormatter from either date or time style (does not matter, we will override the pattern).
+    // We do need to get separate patterns for the date & time styles.
+    if (baseDateStyle != UDAT_NONE) {
+        df = createDateInstance((EStyle)baseDateStyle, locale);
+        fDateTimeFormatter=dynamic_cast<SimpleDateFormat *>(df);
+        if (fDateTimeFormatter == nullptr) {
+            status = U_UNSUPPORTED_ERROR;
+             return;
+        }
+        fDateTimeFormatter->toPattern(fDatePattern);
+        if (timeStyle != UDAT_NONE) {
+            df = createTimeInstance((EStyle)timeStyle, locale);
+            SimpleDateFormat *sdf = dynamic_cast<SimpleDateFormat *>(df);
+            if (sdf != nullptr) {
+                sdf->toPattern(fTimePattern);
+                delete sdf;
+            }
+        }
+    } else {
+        // does not matter whether timeStyle is UDAT_NONE, we need something for fDateTimeFormatter
+        df = createTimeInstance((EStyle)timeStyle, locale);
+        fDateTimeFormatter=dynamic_cast<SimpleDateFormat *>(df);
+        if (fDateTimeFormatter == nullptr) {
+            status = U_UNSUPPORTED_ERROR;
+            delete df;
+            return;
+        }
+        fDateTimeFormatter->toPattern(fTimePattern);
+    }
+
+    // Initialize the parent fCalendar, so that parse() works correctly.
+    initializeCalendar(nullptr, locale, status);
+    loadDates(status);
+}
+
+RelativeDateFormat::~RelativeDateFormat() {
+    delete fDateTimeFormatter;
+    delete fCombinedFormat;
+    uprv_free(fDates);
+#if !UCONFIG_NO_BREAK_ITERATION
+    delete fCapitalizationBrkIter;
+#endif
+}
+
+
+RelativeDateFormat* RelativeDateFormat::clone() const {
+    return new RelativeDateFormat(*this);
+}
+
+bool RelativeDateFormat::operator==(const Format& other) const {
+    if(DateFormat::operator==(other)) {
+        // The DateFormat::operator== check for fCapitalizationContext equality above
+        //   is sufficient to check equality of all derived context-related data.
+        // DateFormat::operator== guarantees following cast is safe
+        RelativeDateFormat* that = (RelativeDateFormat*)&other;
+        return (fDateStyle==that->fDateStyle   &&
+                fDatePattern==that->fDatePattern   &&
+                fTimePattern==that->fTimePattern   &&
+                fLocale==that->fLocale );
+    }
+    return false;
+}
+
+static const char16_t APOSTROPHE = (char16_t)0x0027;
+
+UnicodeString& RelativeDateFormat::format(  Calendar& cal,
+                                UnicodeString& appendTo,
+                                FieldPosition& pos) const {
+                                
+    UErrorCode status = U_ZERO_ERROR;
+    UnicodeString relativeDayString;
+    UDisplayContext capitalizationContext = getContext(UDISPCTX_TYPE_CAPITALIZATION, status);
+    
+    // calculate the difference, in days, between 'cal' and now.
+    int dayDiff = dayDifference(cal, status);
+
+    // look up string
+    int32_t len = 0;
+    const char16_t *theString = getStringForDay(dayDiff, len, status);
+    if(U_SUCCESS(status) && (theString!=nullptr)) {
+        // found a relative string
+        relativeDayString.setTo(theString, len);
+    }
+
+    if ( relativeDayString.length() > 0 && !fDatePattern.isEmpty() && 
+         (fTimePattern.isEmpty() || fCombinedFormat == nullptr || fCombinedHasDateAtStart)) {
+#if !UCONFIG_NO_BREAK_ITERATION
+        // capitalize relativeDayString according to context for relative, set formatter no context
+        if ( u_islower(relativeDayString.char32At(0)) && fCapitalizationBrkIter!= nullptr &&
+             ( capitalizationContext==UDISPCTX_CAPITALIZATION_FOR_BEGINNING_OF_SENTENCE ||
+               (capitalizationContext==UDISPCTX_CAPITALIZATION_FOR_UI_LIST_OR_MENU && fCapitalizationOfRelativeUnitsForUIListMenu) ||
+               (capitalizationContext==UDISPCTX_CAPITALIZATION_FOR_STANDALONE && fCapitalizationOfRelativeUnitsForStandAlone) ) ) {
+            // titlecase first word of relativeDayString
+            relativeDayString.toTitle(fCapitalizationBrkIter, fLocale, U_TITLECASE_NO_LOWERCASE | U_TITLECASE_NO_BREAK_ADJUSTMENT);
+        }
+#endif
+        fDateTimeFormatter->setContext(UDISPCTX_CAPITALIZATION_NONE, status);
+    } else {
+        // set our context for the formatter
+        fDateTimeFormatter->setContext(capitalizationContext, status);
+    }
+
+    if (fDatePattern.isEmpty()) {
+        fDateTimeFormatter->applyPattern(fTimePattern);
+        fDateTimeFormatter->format(cal,appendTo,pos);
+    } else if (fTimePattern.isEmpty() || fCombinedFormat == nullptr) {
+        if (relativeDayString.length() > 0) {
+            appendTo.append(relativeDayString);
+        } else {
+            fDateTimeFormatter->applyPattern(fDatePattern);
+            fDateTimeFormatter->format(cal,appendTo,pos);
+        }
+    } else {
+        UnicodeString datePattern;
+        if (relativeDayString.length() > 0) {
+            // Need to quote the relativeDayString to make it a legal date pattern
+            relativeDayString.findAndReplace(UNICODE_STRING("'", 1), UNICODE_STRING("''", 2)); // double any existing APOSTROPHE
+            relativeDayString.insert(0, APOSTROPHE); // add APOSTROPHE at beginning...
+            relativeDayString.append(APOSTROPHE); // and at end
+            datePattern.setTo(relativeDayString);
+        } else {
+            datePattern.setTo(fDatePattern);
+        }
+        UnicodeString combinedPattern;
+        fCombinedFormat->format(fTimePattern, datePattern, combinedPattern, status);
+        fDateTimeFormatter->applyPattern(combinedPattern);
+        fDateTimeFormatter->format(cal,appendTo,pos);
+    }
+
+    return appendTo;
+}
+
+
+
+UnicodeString&
+RelativeDateFormat::format(const Formattable& obj, 
+                         UnicodeString& appendTo, 
+                         FieldPosition& pos,
+                         UErrorCode& status) const
+{
+    // this is just here to get around the hiding problem
+    // (the previous format() override would hide the version of
+    // format() on DateFormat that this function correspond to, so we
+    // have to redefine it here)
+    return DateFormat::format(obj, appendTo, pos, status);
+}
+
+
+void RelativeDateFormat::parse( const UnicodeString& text,
+                    Calendar& cal,
+                    ParsePosition& pos) const {
+
+    int32_t startIndex = pos.getIndex();
+    if (fDatePattern.isEmpty()) {
+        // no date pattern, try parsing as time
+        fDateTimeFormatter->applyPattern(fTimePattern);
+        fDateTimeFormatter->parse(text,cal,pos);
+    } else if (fTimePattern.isEmpty() || fCombinedFormat == nullptr) {
+        // no time pattern or way to combine, try parsing as date
+        // first check whether text matches a relativeDayString
+        UBool matchedRelative = false;
+        for (int n=0; n < fDatesLen && !matchedRelative; n++) {
+            if (fDates[n].string != nullptr &&
+                    text.compare(startIndex, fDates[n].len, fDates[n].string) == 0) {
+                // it matched, handle the relative day string
+                UErrorCode status = U_ZERO_ERROR;
+                matchedRelative = true;
+
+                // Set the calendar to now+offset
+                cal.setTime(Calendar::getNow(),status);
+                cal.add(UCAL_DATE,fDates[n].offset, status);
+
+                if(U_FAILURE(status)) { 
+                    // failure in setting calendar field, set offset to beginning of rel day string
+                    pos.setErrorIndex(startIndex);
+                } else {
+                    pos.setIndex(startIndex + fDates[n].len);
+                }
+            }
+        }
+        if (!matchedRelative) {
+            // just parse as normal date
+            fDateTimeFormatter->applyPattern(fDatePattern);
+            fDateTimeFormatter->parse(text,cal,pos);
+        }
+    } else {
+        // Here we replace any relativeDayString in text with the equivalent date
+        // formatted per fDatePattern, then parse text normally using the combined pattern.
+        UnicodeString modifiedText(text);
+        FieldPosition fPos;
+        int32_t dateStart = 0, origDateLen = 0, modDateLen = 0;
+        UErrorCode status = U_ZERO_ERROR;
+        for (int n=0; n < fDatesLen; n++) {
+            int32_t relativeStringOffset;
+            if (fDates[n].string != nullptr &&
+                    (relativeStringOffset = modifiedText.indexOf(fDates[n].string, fDates[n].len, startIndex)) >= startIndex) {
+                // it matched, replace the relative date with a real one for parsing
+                UnicodeString dateString;
+                Calendar * tempCal = cal.clone();
+
+                // Set the calendar to now+offset
+                tempCal->setTime(Calendar::getNow(),status);
+                tempCal->add(UCAL_DATE,fDates[n].offset, status);
+                if(U_FAILURE(status)) { 
+                    pos.setErrorIndex(startIndex);
+                    delete tempCal;
+                    return;
+                }
+
+                fDateTimeFormatter->applyPattern(fDatePattern);
+                fDateTimeFormatter->format(*tempCal, dateString, fPos);
+                dateStart = relativeStringOffset;
+                origDateLen = fDates[n].len;
+                modDateLen = dateString.length();
+                modifiedText.replace(dateStart, origDateLen, dateString);
+                delete tempCal;
+                break;
+            }
+        }
+        UnicodeString combinedPattern;
+        fCombinedFormat->format(fTimePattern, fDatePattern, combinedPattern, status);
+        fDateTimeFormatter->applyPattern(combinedPattern);
+        fDateTimeFormatter->parse(modifiedText,cal,pos);
+
+        // Adjust offsets
+        UBool noError = (pos.getErrorIndex() < 0);
+        int32_t offset = (noError)? pos.getIndex(): pos.getErrorIndex();
+        if (offset >= dateStart + modDateLen) {
+            // offset at or after the end of the replaced text,
+            // correct by the difference between original and replacement
+            offset -= (modDateLen - origDateLen);
+        } else if (offset >= dateStart) {
+            // offset in the replaced text, set it to the beginning of that text
+            // (i.e. the beginning of the relative day string)
+            offset = dateStart;
+        }
+        if (noError) {
+            pos.setIndex(offset);
+        } else {
+            pos.setErrorIndex(offset);
+        }
+    }
+}
+
+UDate
+RelativeDateFormat::parse( const UnicodeString& text,
+                         ParsePosition& pos) const {
+    // redefined here because the other parse() function hides this function's
+    // counterpart on DateFormat
+    return DateFormat::parse(text, pos);
+}
+
+UDate
+RelativeDateFormat::parse(const UnicodeString& text, UErrorCode& status) const
+{
+    // redefined here because the other parse() function hides this function's
+    // counterpart on DateFormat
+    return DateFormat::parse(text, status);
+}
+
+
+const char16_t *RelativeDateFormat::getStringForDay(int32_t day, int32_t &len, UErrorCode &status) const {
+    if(U_FAILURE(status)) {
+        return nullptr;
+    }
+
+    // Is it inside the resource bundle's range?
+    int n = day + UDAT_DIRECTION_THIS;
+    if (n >= 0 && n < fDatesLen) {
+        if (fDates[n].offset == day && fDates[n].string != nullptr) {
+            len = fDates[n].len;
+            return fDates[n].string;
+        }
+    }
+    return nullptr;  // not found.
+}
+
+UnicodeString&
+RelativeDateFormat::toPattern(UnicodeString& result, UErrorCode& status) const
+{
+    if (!U_FAILURE(status)) {
+        result.remove();
+        if (fDatePattern.isEmpty()) {
+            result.setTo(fTimePattern);
+        } else if (fTimePattern.isEmpty() || fCombinedFormat == nullptr) {
+            result.setTo(fDatePattern);
+        } else {
+            fCombinedFormat->format(fTimePattern, fDatePattern, result, status);
+        }
+    }
+    return result;
+}
+
+UnicodeString&
+RelativeDateFormat::toPatternDate(UnicodeString& result, UErrorCode& status) const
+{
+    if (!U_FAILURE(status)) {
+        result.remove();
+        result.setTo(fDatePattern);
+    }
+    return result;
+}
+
+UnicodeString&
+RelativeDateFormat::toPatternTime(UnicodeString& result, UErrorCode& status) const
+{
+    if (!U_FAILURE(status)) {
+        result.remove();
+        result.setTo(fTimePattern);
+    }
+    return result;
+}
+
+void
+RelativeDateFormat::applyPatterns(const UnicodeString& datePattern, const UnicodeString& timePattern, UErrorCode &status)
+{
+    if (!U_FAILURE(status)) {
+        fDatePattern.setTo(datePattern);
+        fTimePattern.setTo(timePattern);
+    }
+}
+
+const DateFormatSymbols*
+RelativeDateFormat::getDateFormatSymbols() const
+{
+    return fDateTimeFormatter->getDateFormatSymbols();
+}
+
+// override the DateFormat implementation in order to
+// lazily initialize relevant items
+void
+RelativeDateFormat::setContext(UDisplayContext value, UErrorCode& status)
+{
+    DateFormat::setContext(value, status);
+    if (U_SUCCESS(status)) {
+        if (!fCapitalizationInfoSet &&
+                (value==UDISPCTX_CAPITALIZATION_FOR_UI_LIST_OR_MENU || value==UDISPCTX_CAPITALIZATION_FOR_STANDALONE)) {
+            initCapitalizationContextInfo(fLocale);
+            fCapitalizationInfoSet = true;
+        }
+#if !UCONFIG_NO_BREAK_ITERATION
+        if ( fCapitalizationBrkIter == nullptr && (value==UDISPCTX_CAPITALIZATION_FOR_BEGINNING_OF_SENTENCE ||
+                (value==UDISPCTX_CAPITALIZATION_FOR_UI_LIST_OR_MENU && fCapitalizationOfRelativeUnitsForUIListMenu) ||
+                (value==UDISPCTX_CAPITALIZATION_FOR_STANDALONE && fCapitalizationOfRelativeUnitsForStandAlone)) ) {
+            status = U_ZERO_ERROR;
+            fCapitalizationBrkIter = BreakIterator::createSentenceInstance(fLocale, status);
+            if (U_FAILURE(status)) {
+                delete fCapitalizationBrkIter;
+                fCapitalizationBrkIter = nullptr;
+            }
+        }
+#endif
+    }
+}
+
+void
+RelativeDateFormat::initCapitalizationContextInfo(const Locale& thelocale)
+{
+#if !UCONFIG_NO_BREAK_ITERATION
+    const char * localeID = (thelocale != nullptr)? thelocale.getBaseName(): nullptr;
+    UErrorCode status = U_ZERO_ERROR;
+    LocalUResourceBundlePointer rb(ures_open(nullptr, localeID, &status));
+    ures_getByKeyWithFallback(rb.getAlias(),
+                              "contextTransforms/relative",
+                               rb.getAlias(), &status);
+    if (U_SUCCESS(status) && rb != nullptr) {
+        int32_t len = 0;
+        const int32_t * intVector = ures_getIntVector(rb.getAlias(),
+                                                      &len, &status);
+        if (U_SUCCESS(status) && intVector != nullptr && len >= 2) {
+            fCapitalizationOfRelativeUnitsForUIListMenu = static_cast<UBool>(intVector[0]);
+            fCapitalizationOfRelativeUnitsForStandAlone = static_cast<UBool>(intVector[1]);
+        }
+    }
+#endif
+}
+
+namespace {
+
+/**
+ * Sink for getting data from fields/day/relative data.
+ * For loading relative day names, e.g., "yesterday", "today".
+ */
+
+struct RelDateFmtDataSink : public ResourceSink {
+  URelativeString *fDatesPtr;
+  int32_t fDatesLen;
+
+  RelDateFmtDataSink(URelativeString* fDates, int32_t len) : fDatesPtr(fDates), fDatesLen(len) {
+    for (int32_t i = 0; i < fDatesLen; ++i) {
+      fDatesPtr[i].offset = 0;
+      fDatesPtr[i].string = nullptr;
+      fDatesPtr[i].len = -1;
+    }
+  }
+
+  virtual ~RelDateFmtDataSink();
+
+  virtual void put(const char *key, ResourceValue &value,
+                   UBool /*noFallback*/, UErrorCode &errorCode) override {
+      ResourceTable relDayTable = value.getTable(errorCode);
+      int32_t n = 0;
+      int32_t len = 0;
+      for (int32_t i = 0; relDayTable.getKeyAndValue(i, key, value); ++i) {
+        // Find the relative offset.
+        int32_t offset = atoi(key);
+
+        // Put in the proper spot, but don't override existing data.
+        n = offset + UDAT_DIRECTION_THIS; // Converts to index in UDAT_R
+        if (n < fDatesLen && fDatesPtr[n].string == nullptr) {
+          // Not found and n is an empty slot.
+          fDatesPtr[n].offset = offset;
+          fDatesPtr[n].string = value.getString(len, errorCode);
+          fDatesPtr[n].len = len;
+        }
+      }
+  }
+};
+
+
+// Virtual destructors must be defined out of line.
+RelDateFmtDataSink::~RelDateFmtDataSink() {}
+
+}  // Namespace
+
+
+static const char16_t patItem1[] = {0x7B,0x31,0x7D}; // "{1}"
+static const int32_t patItem1Len = 3;
+
+void RelativeDateFormat::loadDates(UErrorCode &status) {
+    UResourceBundle *rb = ures_open(nullptr, fLocale.getBaseName(), &status);
+    LocalUResourceBundlePointer dateTimePatterns(
+        ures_getByKeyWithFallback(rb,
+                                  "calendar/gregorian/DateTimePatterns",
+                                  (UResourceBundle*)nullptr, &status));
+    if(U_SUCCESS(status)) {
+        int32_t patternsSize = ures_getSize(dateTimePatterns.getAlias());
+        if (patternsSize > kDateTime) {
+            int32_t resStrLen = 0;
+            int32_t glueIndex = kDateTime;
+            if (patternsSize >= (kDateTimeOffset + kShort + 1)) {
+                int32_t offsetIncrement = (fDateStyle & ~kRelative); // Remove relative bit.
+                if (offsetIncrement >= (int32_t)kFull &&
+                    offsetIncrement <= (int32_t)kShortRelative) {
+                    glueIndex = kDateTimeOffset + offsetIncrement;
+                }
+            }
+
+            const char16_t *resStr = ures_getStringByIndex(dateTimePatterns.getAlias(), glueIndex, &resStrLen, &status);
+            if (U_SUCCESS(status) && resStrLen >= patItem1Len && u_strncmp(resStr,patItem1,patItem1Len)==0) {
+                fCombinedHasDateAtStart = true;
+            }
+            fCombinedFormat = new SimpleFormatter(UnicodeString(true, resStr, resStrLen), 2, 2, status);
+        }
+    }
+
+    // Data loading for relative names, e.g., "yesterday", "today", "tomorrow".
+    fDatesLen = UDAT_DIRECTION_COUNT; // Maximum defined by data.
+    fDates = (URelativeString*) uprv_malloc(sizeof(fDates[0])*fDatesLen);
+
+    RelDateFmtDataSink sink(fDates, fDatesLen);
+    ures_getAllItemsWithFallback(rb, "fields/day/relative", sink, status);
+
+    ures_close(rb);
+
+    if(U_FAILURE(status)) {
+        fDatesLen=0;
+        return;
+    }
+}
+
+//----------------------------------------------------------------------
+
+// this should to be in DateFormat, instead it was copied from SimpleDateFormat.
+
+Calendar*
+RelativeDateFormat::initializeCalendar(TimeZone* adoptZone, const Locale& locale, UErrorCode& status)
+{
+    if(!U_FAILURE(status)) {
+        fCalendar = Calendar::createInstance(adoptZone?adoptZone:TimeZone::createDefault(), locale, status);
+    }
+    if (U_SUCCESS(status) && fCalendar == nullptr) {
+        status = U_MEMORY_ALLOCATION_ERROR;
+    }
+    return fCalendar;
+}
+
+int32_t RelativeDateFormat::dayDifference(Calendar &cal, UErrorCode &status) {
+    if(U_FAILURE(status)) {
+        return 0;
+    }
+    // TODO: Cache the nowCal to avoid heap allocs? Would be difficult, don't know the calendar type
+    Calendar *nowCal = cal.clone();
+    nowCal->setTime(Calendar::getNow(), status);
+
+    // For the day difference, we are interested in the difference in the (modified) julian day number
+    // which is midnight to midnight.  Using fieldDifference() is NOT correct here, because 
+    // 6pm Jan 4th  to 10am Jan 5th should be considered "tomorrow".
+    int32_t dayDiff = cal.get(UCAL_JULIAN_DAY, status) - nowCal->get(UCAL_JULIAN_DAY, status);
+
+    delete nowCal;
+    return dayDiff;
+}
+
+U_NAMESPACE_END
+
+#endif  /* !UCONFIG_NO_FORMATTING */