Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

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

1 files changed, 2006 insertions, 0 deletions

diff --git a/intl/icu/source/i18n/plurrule.cpp b/intl/icu/source/i18n/plurrule.cpp
new file mode 100644
index 0000000000..9c37b09e25
--- /dev/null
+++ b/intl/icu/source/i18n/plurrule.cpp
@@ -0,0 +1,2006 @@
+// © 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.
+*******************************************************************************
+*
+* File plurrule.cpp
+*/
+
+#include <math.h>
+#include <stdio.h>
+
+#include "unicode/utypes.h"
+#include "unicode/localpointer.h"
+#include "unicode/plurrule.h"
+#include "unicode/upluralrules.h"
+#include "unicode/ures.h"
+#include "unicode/numfmt.h"
+#include "unicode/decimfmt.h"
+#include "unicode/numberrangeformatter.h"
+#include "charstr.h"
+#include "cmemory.h"
+#include "cstring.h"
+#include "hash.h"
+#include "locutil.h"
+#include "mutex.h"
+#include "number_decnum.h"
+#include "patternprops.h"
+#include "plurrule_impl.h"
+#include "putilimp.h"
+#include "ucln_in.h"
+#include "ustrfmt.h"
+#include "uassert.h"
+#include "uvectr32.h"
+#include "sharedpluralrules.h"
+#include "unifiedcache.h"
+#include "number_decimalquantity.h"
+#include "util.h"
+#include "pluralranges.h"
+#include "numrange_impl.h"
+
+#if !UCONFIG_NO_FORMATTING
+
+U_NAMESPACE_BEGIN
+
+using namespace icu::pluralimpl;
+using icu::number::impl::DecNum;
+using icu::number::impl::DecimalQuantity;
+using icu::number::impl::RoundingMode;
+
+static const char16_t PLURAL_KEYWORD_OTHER[]={LOW_O,LOW_T,LOW_H,LOW_E,LOW_R,0};
+static const char16_t PLURAL_DEFAULT_RULE[]={LOW_O,LOW_T,LOW_H,LOW_E,LOW_R,COLON,SPACE,LOW_N,0};
+static const char16_t PK_IN[]={LOW_I,LOW_N,0};
+static const char16_t PK_NOT[]={LOW_N,LOW_O,LOW_T,0};
+static const char16_t PK_IS[]={LOW_I,LOW_S,0};
+static const char16_t PK_MOD[]={LOW_M,LOW_O,LOW_D,0};
+static const char16_t PK_AND[]={LOW_A,LOW_N,LOW_D,0};
+static const char16_t PK_OR[]={LOW_O,LOW_R,0};
+static const char16_t PK_VAR_N[]={LOW_N,0};
+static const char16_t PK_VAR_I[]={LOW_I,0};
+static const char16_t PK_VAR_F[]={LOW_F,0};
+static const char16_t PK_VAR_T[]={LOW_T,0};
+static const char16_t PK_VAR_E[]={LOW_E,0};
+static const char16_t PK_VAR_C[]={LOW_C,0};
+static const char16_t PK_VAR_V[]={LOW_V,0};
+static const char16_t PK_WITHIN[]={LOW_W,LOW_I,LOW_T,LOW_H,LOW_I,LOW_N,0};
+static const char16_t PK_DECIMAL[]={LOW_D,LOW_E,LOW_C,LOW_I,LOW_M,LOW_A,LOW_L,0};
+static const char16_t PK_INTEGER[]={LOW_I,LOW_N,LOW_T,LOW_E,LOW_G,LOW_E,LOW_R,0};
+
+UOBJECT_DEFINE_RTTI_IMPLEMENTATION(PluralRules)
+UOBJECT_DEFINE_RTTI_IMPLEMENTATION(PluralKeywordEnumeration)
+
+PluralRules::PluralRules(UErrorCode& /*status*/)
+:   UObject(),
+    mRules(nullptr),
+    mStandardPluralRanges(nullptr),
+    mInternalStatus(U_ZERO_ERROR)
+{
+}
+
+PluralRules::PluralRules(const PluralRules& other)
+: UObject(other),
+    mRules(nullptr),
+    mStandardPluralRanges(nullptr),
+    mInternalStatus(U_ZERO_ERROR)
+{
+    *this=other;
+}
+
+PluralRules::~PluralRules() {
+    delete mRules;
+    delete mStandardPluralRanges;
+}
+
+SharedPluralRules::~SharedPluralRules() {
+    delete ptr;
+}
+
+PluralRules*
+PluralRules::clone() const {
+    // Since clone doesn't have a 'status' parameter, the best we can do is return nullptr if
+    // the newly created object was not fully constructed properly (an error occurred).
+    UErrorCode localStatus = U_ZERO_ERROR;
+    return clone(localStatus);
+}
+
+PluralRules*
+PluralRules::clone(UErrorCode& status) const {
+    LocalPointer<PluralRules> newObj(new PluralRules(*this), status);
+    if (U_SUCCESS(status) && U_FAILURE(newObj->mInternalStatus)) {
+        status = newObj->mInternalStatus;
+        newObj.adoptInstead(nullptr);
+    }
+    return newObj.orphan();
+}
+
+PluralRules&
+PluralRules::operator=(const PluralRules& other) {
+    if (this != &other) {
+        delete mRules;
+        mRules = nullptr;
+        delete mStandardPluralRanges;
+        mStandardPluralRanges = nullptr;
+        mInternalStatus = other.mInternalStatus;
+        if (U_FAILURE(mInternalStatus)) {
+            // bail out early if the object we were copying from was already 'invalid'.
+            return *this;
+        }
+        if (other.mRules != nullptr) {
+            mRules = new RuleChain(*other.mRules);
+            if (mRules == nullptr) {
+                mInternalStatus = U_MEMORY_ALLOCATION_ERROR;
+            }
+            else if (U_FAILURE(mRules->fInternalStatus)) {
+                // If the RuleChain wasn't fully copied, then set our status to failure as well.
+                mInternalStatus = mRules->fInternalStatus;
+            }
+        }
+        if (other.mStandardPluralRanges != nullptr) {
+            mStandardPluralRanges = other.mStandardPluralRanges->copy(mInternalStatus)
+                .toPointer(mInternalStatus)
+                .orphan();
+        }
+    }
+    return *this;
+}
+
+StringEnumeration* PluralRules::getAvailableLocales(UErrorCode &status) {
+    if (U_FAILURE(status)) {
+        return nullptr;
+    }
+    LocalPointer<StringEnumeration> result(new PluralAvailableLocalesEnumeration(status), status);
+    if (U_FAILURE(status)) {
+        return nullptr;
+    }
+    return result.orphan();
+}
+
+
+PluralRules* U_EXPORT2
+PluralRules::createRules(const UnicodeString& description, UErrorCode& status) {
+    if (U_FAILURE(status)) {
+        return nullptr;
+    }
+    PluralRuleParser parser;
+    LocalPointer<PluralRules> newRules(new PluralRules(status), status);
+    if (U_FAILURE(status)) {
+        return nullptr;
+    }
+    parser.parse(description, newRules.getAlias(), status);
+    if (U_FAILURE(status)) {
+        newRules.adoptInstead(nullptr);
+    }
+    return newRules.orphan();
+}
+
+
+PluralRules* U_EXPORT2
+PluralRules::createDefaultRules(UErrorCode& status) {
+    return createRules(UnicodeString(true, PLURAL_DEFAULT_RULE, -1), status);
+}
+
+/******************************************************************************/
+/* Create PluralRules cache */
+
+template<> U_I18N_API
+const SharedPluralRules *LocaleCacheKey<SharedPluralRules>::createObject(
+        const void * /*unused*/, UErrorCode &status) const {
+    const char *localeId = fLoc.getName();
+    LocalPointer<PluralRules> pr(PluralRules::internalForLocale(localeId, UPLURAL_TYPE_CARDINAL, status), status);
+    if (U_FAILURE(status)) {
+        return nullptr;
+    }
+    LocalPointer<SharedPluralRules> result(new SharedPluralRules(pr.getAlias()), status);
+    if (U_FAILURE(status)) {
+        return nullptr;
+    }
+    pr.orphan(); // result was successfully created so it nows pr.
+    result->addRef();
+    return result.orphan();
+}
+
+/* end plural rules cache */
+/******************************************************************************/
+
+const SharedPluralRules* U_EXPORT2
+PluralRules::createSharedInstance(
+        const Locale& locale, UPluralType type, UErrorCode& status) {
+    if (U_FAILURE(status)) {
+        return nullptr;
+    }
+    if (type != UPLURAL_TYPE_CARDINAL) {
+        status = U_UNSUPPORTED_ERROR;
+        return nullptr;
+    }
+    const SharedPluralRules *result = nullptr;
+    UnifiedCache::getByLocale(locale, result, status);
+    return result;
+}
+
+PluralRules* U_EXPORT2
+PluralRules::forLocale(const Locale& locale, UErrorCode& status) {
+    return forLocale(locale, UPLURAL_TYPE_CARDINAL, status);
+}
+
+PluralRules* U_EXPORT2
+PluralRules::forLocale(const Locale& locale, UPluralType type, UErrorCode& status) {
+    if (type != UPLURAL_TYPE_CARDINAL) {
+        return internalForLocale(locale, type, status);
+    }
+    const SharedPluralRules *shared = createSharedInstance(
+            locale, type, status);
+    if (U_FAILURE(status)) {
+        return nullptr;
+    }
+    PluralRules *result = (*shared)->clone(status);
+    shared->removeRef();
+    return result;
+}
+
+PluralRules* U_EXPORT2
+PluralRules::internalForLocale(const Locale& locale, UPluralType type, UErrorCode& status) {
+    if (U_FAILURE(status)) {
+        return nullptr;
+    }
+    if (type >= UPLURAL_TYPE_COUNT) {
+        status = U_ILLEGAL_ARGUMENT_ERROR;
+        return nullptr;
+    }
+    LocalPointer<PluralRules> newObj(new PluralRules(status), status);
+    if (U_FAILURE(status)) {
+        return nullptr;
+    }
+    UnicodeString locRule = newObj->getRuleFromResource(locale, type, status);
+    // TODO: which other errors, if any, should be returned?
+    if (locRule.length() == 0) {
+        // If an out-of-memory error occurred, then stop and report the failure.
+        if (status == U_MEMORY_ALLOCATION_ERROR) {
+            return nullptr;
+        }
+        // Locales with no specific rules (all numbers have the "other" category
+        //   will return a U_MISSING_RESOURCE_ERROR at this point. This is not
+        //   an error.
+        locRule =  UnicodeString(PLURAL_DEFAULT_RULE);
+        status = U_ZERO_ERROR;
+    }
+    PluralRuleParser parser;
+    parser.parse(locRule, newObj.getAlias(), status);
+        //  TODO: should rule parse errors be returned, or
+        //        should we silently use default rules?
+        //        Original impl used default rules.
+        //        Ask the question to ICU Core.
+
+    newObj->mStandardPluralRanges = StandardPluralRanges::forLocale(locale, status)
+        .toPointer(status)
+        .orphan();
+
+    return newObj.orphan();
+}
+
+UnicodeString
+PluralRules::select(int32_t number) const {
+    return select(FixedDecimal(number));
+}
+
+UnicodeString
+PluralRules::select(double number) const {
+    return select(FixedDecimal(number));
+}
+
+UnicodeString
+PluralRules::select(const number::FormattedNumber& number, UErrorCode& status) const {
+    DecimalQuantity dq;
+    number.getDecimalQuantity(dq, status);
+    if (U_FAILURE(status)) {
+        return ICU_Utility::makeBogusString();
+    }
+    if (U_FAILURE(mInternalStatus)) {
+        status = mInternalStatus;
+        return ICU_Utility::makeBogusString();
+    }
+    return select(dq);
+}
+
+UnicodeString
+PluralRules::select(const IFixedDecimal &number) const {
+    if (mRules == nullptr) {
+        return UnicodeString(true, PLURAL_DEFAULT_RULE, -1);
+    }
+    else {
+        return mRules->select(number);
+    }
+}
+
+UnicodeString
+PluralRules::select(const number::FormattedNumberRange& range, UErrorCode& status) const {
+    return select(range.getData(status), status);
+}
+
+UnicodeString
+PluralRules::select(const number::impl::UFormattedNumberRangeData* impl, UErrorCode& status) const {
+    if (U_FAILURE(status)) {
+        return ICU_Utility::makeBogusString();
+    }
+    if (U_FAILURE(mInternalStatus)) {
+        status = mInternalStatus;
+        return ICU_Utility::makeBogusString();
+    }
+    if (mStandardPluralRanges == nullptr) {
+        // Happens if PluralRules was constructed via createRules()
+        status = U_UNSUPPORTED_ERROR;
+        return ICU_Utility::makeBogusString();
+    }
+    auto form1 = StandardPlural::fromString(select(impl->quantity1), status);
+    auto form2 = StandardPlural::fromString(select(impl->quantity2), status);
+    if (U_FAILURE(status)) {
+        return ICU_Utility::makeBogusString();
+    }
+    auto result = mStandardPluralRanges->resolve(form1, form2);
+    return UnicodeString(StandardPlural::getKeyword(result), -1, US_INV);
+}
+
+
+StringEnumeration*
+PluralRules::getKeywords(UErrorCode& status) const {
+    if (U_FAILURE(status)) {
+        return nullptr;
+    }
+    if (U_FAILURE(mInternalStatus)) {
+        status = mInternalStatus;
+        return nullptr;
+    }
+    LocalPointer<StringEnumeration> nameEnumerator(new PluralKeywordEnumeration(mRules, status), status);
+    if (U_FAILURE(status)) {
+        return nullptr;
+    }
+    return nameEnumerator.orphan();
+}
+
+double
+PluralRules::getUniqueKeywordValue(const UnicodeString& /* keyword */) {
+  // Not Implemented.
+  return UPLRULES_NO_UNIQUE_VALUE;
+}
+
+int32_t
+PluralRules::getAllKeywordValues(const UnicodeString & /* keyword */, double * /* dest */,
+                                 int32_t /* destCapacity */, UErrorCode& error) {
+    error = U_UNSUPPORTED_ERROR;
+    return 0;
+}
+
+/**
+ * Helper method for the overrides of getSamples() for double and DecimalQuantity
+ * return value types.  Provide only one of an allocated array of double or
+ * DecimalQuantity, and a nullptr for the other.
+ */
+static int32_t
+getSamplesFromString(const UnicodeString &samples, double *destDbl,
+                        DecimalQuantity* destDq, int32_t destCapacity,
+                        UErrorCode& status) {
+
+    if ((destDbl == nullptr && destDq == nullptr)
+            || (destDbl != nullptr && destDq != nullptr)) {
+        status = U_INTERNAL_PROGRAM_ERROR;
+        return 0;
+    }
+
+    bool isDouble = destDbl != nullptr;
+    int32_t sampleCount = 0;
+    int32_t sampleStartIdx = 0;
+    int32_t sampleEndIdx = 0;
+
+    //std::string ss;  // TODO: debugging.
+    // std::cout << "PluralRules::getSamples(), samples = \"" << samples.toUTF8String(ss) << "\"\n";
+    for (sampleCount = 0; sampleCount < destCapacity && sampleStartIdx < samples.length(); ) {
+        sampleEndIdx = samples.indexOf(COMMA, sampleStartIdx);
+        if (sampleEndIdx == -1) {
+            sampleEndIdx = samples.length();
+        }
+        const UnicodeString &sampleRange = samples.tempSubStringBetween(sampleStartIdx, sampleEndIdx);
+        // ss.erase();
+        // std::cout << "PluralRules::getSamples(), samplesRange = \"" << sampleRange.toUTF8String(ss) << "\"\n";
+        int32_t tildeIndex = sampleRange.indexOf(TILDE);
+        if (tildeIndex < 0) {
+            DecimalQuantity dq = DecimalQuantity::fromExponentString(sampleRange, status);
+            if (isDouble) {
+                // See warning note below about lack of precision for floating point samples for numbers with
+                // trailing zeroes in the decimal fraction representation.
+                double dblValue = dq.toDouble();
+                if (!(dblValue == floor(dblValue) && dq.fractionCount() > 0)) {
+                    destDbl[sampleCount++] = dblValue;
+                }
+            } else {
+                destDq[sampleCount++] = dq;
+            }
+        } else {
+            DecimalQuantity rangeLo =
+                DecimalQuantity::fromExponentString(sampleRange.tempSubStringBetween(0, tildeIndex), status);
+            DecimalQuantity rangeHi = DecimalQuantity::fromExponentString(sampleRange.tempSubStringBetween(tildeIndex+1), status);
+            if (U_FAILURE(status)) {
+                break;
+            }
+            if (rangeHi.toDouble() < rangeLo.toDouble()) {
+                status = U_INVALID_FORMAT_ERROR;
+                break;
+            }
+
+            DecimalQuantity incrementDq;
+            incrementDq.setToInt(1);
+            int32_t lowerDispMag = rangeLo.getLowerDisplayMagnitude();
+            int32_t exponent = rangeLo.getExponent();
+            int32_t incrementScale = lowerDispMag + exponent;
+            incrementDq.adjustMagnitude(incrementScale);
+            double incrementVal = incrementDq.toDouble();  // 10 ^ incrementScale
+            
+
+            DecimalQuantity dq(rangeLo);
+            double dblValue = dq.toDouble();
+            double end = rangeHi.toDouble();
+
+            while (dblValue <= end) {
+                if (isDouble) {
+                    // Hack Alert: don't return any decimal samples with integer values that
+                    //    originated from a format with trailing decimals.
+                    //    This API is returning doubles, which can't distinguish having displayed
+                    //    zeros to the right of the decimal.
+                    //    This results in test failures with values mapping back to a different keyword.
+                    if (!(dblValue == floor(dblValue) && dq.fractionCount() > 0)) {
+                        destDbl[sampleCount++] = dblValue;
+                    }
+                } else {
+                    destDq[sampleCount++] = dq;
+                }
+                if (sampleCount >= destCapacity) {
+                    break;
+                }
+
+                // Increment dq for next iteration
+
+                // Because DecNum and DecimalQuantity do not support
+                // add operations, we need to convert to/from double,
+                // despite precision lossiness for decimal fractions like 0.1.
+                dblValue += incrementVal;
+                DecNum newDqDecNum;
+                newDqDecNum.setTo(dblValue, status);
+                DecimalQuantity newDq;             
+                newDq.setToDecNum(newDqDecNum, status);
+                newDq.setMinFraction(-lowerDispMag);
+                newDq.roundToMagnitude(lowerDispMag, RoundingMode::UNUM_ROUND_HALFEVEN, status);
+                newDq.adjustMagnitude(-exponent);
+                newDq.adjustExponent(exponent);
+                dblValue = newDq.toDouble();
+                dq = newDq;
+            }
+        }
+        sampleStartIdx = sampleEndIdx + 1;
+    }
+    return sampleCount;
+}
+
+int32_t
+PluralRules::getSamples(const UnicodeString &keyword, double *dest,
+                        int32_t destCapacity, UErrorCode& status) {
+    if (U_FAILURE(status)) {
+        return 0;
+    }
+    if (U_FAILURE(mInternalStatus)) {
+        status = mInternalStatus;
+        return 0;
+    }
+    if (dest != nullptr ? destCapacity < 0 : destCapacity != 0) {
+        status = U_ILLEGAL_ARGUMENT_ERROR;
+        return 0;
+    }
+    RuleChain *rc = rulesForKeyword(keyword);
+    if (rc == nullptr) {
+        return 0;
+    }
+    int32_t numSamples = getSamplesFromString(rc->fIntegerSamples, dest, nullptr, destCapacity, status);
+    if (numSamples == 0) {
+        numSamples = getSamplesFromString(rc->fDecimalSamples, dest, nullptr, destCapacity, status);
+    }
+    return numSamples;
+}
+
+int32_t
+PluralRules::getSamples(const UnicodeString &keyword, DecimalQuantity *dest,
+                        int32_t destCapacity, UErrorCode& status) {
+    if (U_FAILURE(status)) {
+        return 0;
+    }
+    if (U_FAILURE(mInternalStatus)) {
+        status = mInternalStatus;
+        return 0;
+    }
+    if (dest != nullptr ? destCapacity < 0 : destCapacity != 0) {
+        status = U_ILLEGAL_ARGUMENT_ERROR;
+        return 0;
+    }
+    RuleChain *rc = rulesForKeyword(keyword);
+    if (rc == nullptr) {
+        return 0;
+    }
+
+    int32_t numSamples = getSamplesFromString(rc->fIntegerSamples, nullptr, dest, destCapacity, status);
+    if (numSamples == 0) {
+        numSamples = getSamplesFromString(rc->fDecimalSamples, nullptr, dest, destCapacity, status);
+    }
+    return numSamples;
+}
+
+
+RuleChain *PluralRules::rulesForKeyword(const UnicodeString &keyword) const {
+    RuleChain *rc;
+    for (rc = mRules; rc != nullptr; rc = rc->fNext) {
+        if (rc->fKeyword == keyword) {
+            break;
+        }
+    }
+    return rc;
+}
+
+
+UBool
+PluralRules::isKeyword(const UnicodeString& keyword) const {
+    if (0 == keyword.compare(PLURAL_KEYWORD_OTHER, 5)) {
+        return true;
+    }
+    return rulesForKeyword(keyword) != nullptr;
+}
+
+UnicodeString
+PluralRules::getKeywordOther() const {
+    return UnicodeString(true, PLURAL_KEYWORD_OTHER, 5);
+}
+
+bool
+PluralRules::operator==(const PluralRules& other) const  {
+    const UnicodeString *ptrKeyword;
+    UErrorCode status= U_ZERO_ERROR;
+
+    if ( this == &other ) {
+        return true;
+    }
+    LocalPointer<StringEnumeration> myKeywordList(getKeywords(status));
+    LocalPointer<StringEnumeration> otherKeywordList(other.getKeywords(status));
+    if (U_FAILURE(status)) {
+        return false;
+    }
+
+    if (myKeywordList->count(status)!=otherKeywordList->count(status)) {
+        return false;
+    }
+    myKeywordList->reset(status);
+    while ((ptrKeyword=myKeywordList->snext(status))!=nullptr) {
+        if (!other.isKeyword(*ptrKeyword)) {
+            return false;
+        }
+    }
+    otherKeywordList->reset(status);
+    while ((ptrKeyword=otherKeywordList->snext(status))!=nullptr) {
+        if (!this->isKeyword(*ptrKeyword)) {
+            return false;
+        }
+    }
+    if (U_FAILURE(status)) {
+        return false;
+    }
+
+    return true;
+}
+
+
+void
+PluralRuleParser::parse(const UnicodeString& ruleData, PluralRules *prules, UErrorCode &status)
+{
+    if (U_FAILURE(status)) {
+        return;
+    }
+    U_ASSERT(ruleIndex == 0);    // Parsers are good for a single use only!
+    ruleSrc = &ruleData;
+
+    while (ruleIndex< ruleSrc->length()) {
+        getNextToken(status);
+        if (U_FAILURE(status)) {
+            return;
+        }
+        checkSyntax(status);
+        if (U_FAILURE(status)) {
+            return;
+        }
+        switch (type) {
+        case tAnd:
+            U_ASSERT(curAndConstraint != nullptr);
+            curAndConstraint = curAndConstraint->add(status);
+            break;
+        case tOr:
+            {
+                U_ASSERT(currentChain != nullptr);
+                OrConstraint *orNode=currentChain->ruleHeader;
+                while (orNode->next != nullptr) {
+                    orNode = orNode->next;
+                }
+                orNode->next= new OrConstraint();
+                if (orNode->next == nullptr) {
+                    status = U_MEMORY_ALLOCATION_ERROR;
+                    break;
+                }
+                orNode=orNode->next;
+                orNode->next=nullptr;
+                curAndConstraint = orNode->add(status);
+            }
+            break;
+        case tIs:
+            U_ASSERT(curAndConstraint != nullptr);
+            U_ASSERT(curAndConstraint->value == -1);
+            U_ASSERT(curAndConstraint->rangeList == nullptr);
+            break;
+        case tNot:
+            U_ASSERT(curAndConstraint != nullptr);
+            curAndConstraint->negated=true;
+            break;
+
+        case tNotEqual:
+            curAndConstraint->negated=true;
+            U_FALLTHROUGH;
+        case tIn:
+        case tWithin:
+        case tEqual:
+            {
+                U_ASSERT(curAndConstraint != nullptr);
+                LocalPointer<UVector32> newRangeList(new UVector32(status), status);
+                if (U_FAILURE(status)) {
+                    break;
+                }
+                curAndConstraint->rangeList = newRangeList.orphan();
+                curAndConstraint->rangeList->addElement(-1, status);  // range Low
+                curAndConstraint->rangeList->addElement(-1, status);  // range Hi
+                rangeLowIdx = 0;
+                rangeHiIdx  = 1;
+                curAndConstraint->value=PLURAL_RANGE_HIGH;
+                curAndConstraint->integerOnly = (type != tWithin);
+            }
+            break;
+        case tNumber:
+            U_ASSERT(curAndConstraint != nullptr);
+            if ( (curAndConstraint->op==AndConstraint::MOD)&&
+                 (curAndConstraint->opNum == -1 ) ) {
+                curAndConstraint->opNum=getNumberValue(token);
+            }
+            else {
+                if (curAndConstraint->rangeList == nullptr) {
+                    // this is for an 'is' rule
+                    curAndConstraint->value = getNumberValue(token);
+                } else {
+                    // this is for an 'in' or 'within' rule
+                    if (curAndConstraint->rangeList->elementAti(rangeLowIdx) == -1) {
+                        curAndConstraint->rangeList->setElementAt(getNumberValue(token), rangeLowIdx);
+                        curAndConstraint->rangeList->setElementAt(getNumberValue(token), rangeHiIdx);
+                    }
+                    else {
+                        curAndConstraint->rangeList->setElementAt(getNumberValue(token), rangeHiIdx);
+                        if (curAndConstraint->rangeList->elementAti(rangeLowIdx) >
+                                curAndConstraint->rangeList->elementAti(rangeHiIdx)) {
+                            // Range Lower bound > Range Upper bound.
+                            // U_UNEXPECTED_TOKEN seems a little funny, but it is consistently
+                            // used for all plural rule parse errors.
+                            status = U_UNEXPECTED_TOKEN;
+                            break;
+                        }
+                    }
+                }
+            }
+            break;
+        case tComma:
+            // TODO: rule syntax checking is inadequate, can happen with badly formed rules.
+            //       Catch cases like "n mod 10, is 1" here instead.
+            if (curAndConstraint == nullptr || curAndConstraint->rangeList == nullptr) {
+                status = U_UNEXPECTED_TOKEN;
+                break;
+            }
+            U_ASSERT(curAndConstraint->rangeList->size() >= 2);
+            rangeLowIdx = curAndConstraint->rangeList->size();
+            curAndConstraint->rangeList->addElement(-1, status);  // range Low
+            rangeHiIdx = curAndConstraint->rangeList->size();
+            curAndConstraint->rangeList->addElement(-1, status);  // range Hi
+            break;
+        case tMod:
+            U_ASSERT(curAndConstraint != nullptr);
+            curAndConstraint->op=AndConstraint::MOD;
+            break;
+        case tVariableN:
+        case tVariableI:
+        case tVariableF:
+        case tVariableT:
+        case tVariableE:
+        case tVariableC:
+        case tVariableV:
+            U_ASSERT(curAndConstraint != nullptr);
+            curAndConstraint->digitsType = type;
+            break;
+        case tKeyword:
+            {
+            RuleChain *newChain = new RuleChain;
+            if (newChain == nullptr) {
+                status = U_MEMORY_ALLOCATION_ERROR;
+                break;
+            }
+            newChain->fKeyword = token;
+            if (prules->mRules == nullptr) {
+                prules->mRules = newChain;
+            } else {
+                // The new rule chain goes at the end of the linked list of rule chains,
+                //   unless there is an "other" keyword & chain. "other" must remain last.
+                RuleChain *insertAfter = prules->mRules;
+                while (insertAfter->fNext!=nullptr &&
+                       insertAfter->fNext->fKeyword.compare(PLURAL_KEYWORD_OTHER, 5) != 0 ){
+                    insertAfter=insertAfter->fNext;
+                }
+                newChain->fNext = insertAfter->fNext;
+                insertAfter->fNext = newChain;
+            }
+            OrConstraint *orNode = new OrConstraint();
+            if (orNode == nullptr) {
+                status = U_MEMORY_ALLOCATION_ERROR;
+                break;
+            }
+            newChain->ruleHeader = orNode;
+            curAndConstraint = orNode->add(status);
+            currentChain = newChain;
+            }
+            break;
+
+        case tInteger:
+            for (;;) {
+                getNextToken(status);
+                if (U_FAILURE(status) || type == tSemiColon || type == tEOF || type == tAt) {
+                    break;
+                }
+                if (type == tEllipsis) {
+                    currentChain->fIntegerSamplesUnbounded = true;
+                    continue;
+                }
+                currentChain->fIntegerSamples.append(token);
+            }
+            break;
+
+        case tDecimal:
+            for (;;) {
+                getNextToken(status);
+                if (U_FAILURE(status) || type == tSemiColon || type == tEOF || type == tAt) {
+                    break;
+                }
+                if (type == tEllipsis) {
+                    currentChain->fDecimalSamplesUnbounded = true;
+                    continue;
+                }
+                currentChain->fDecimalSamples.append(token);
+            }
+            break;
+
+        default:
+            break;
+        }
+        prevType=type;
+        if (U_FAILURE(status)) {
+            break;
+        }
+    }
+}
+
+UnicodeString
+PluralRules::getRuleFromResource(const Locale& locale, UPluralType type, UErrorCode& errCode) {
+    UnicodeString emptyStr;
+
+    if (U_FAILURE(errCode)) {
+        return emptyStr;
+    }
+    LocalUResourceBundlePointer rb(ures_openDirect(nullptr, "plurals", &errCode));
+    if(U_FAILURE(errCode)) {
+        return emptyStr;
+    }
+    const char *typeKey;
+    switch (type) {
+    case UPLURAL_TYPE_CARDINAL:
+        typeKey = "locales";
+        break;
+    case UPLURAL_TYPE_ORDINAL:
+        typeKey = "locales_ordinals";
+        break;
+    default:
+        // Must not occur: The caller should have checked for valid types.
+        errCode = U_ILLEGAL_ARGUMENT_ERROR;
+        return emptyStr;
+    }
+    LocalUResourceBundlePointer locRes(ures_getByKey(rb.getAlias(), typeKey, nullptr, &errCode));
+    if(U_FAILURE(errCode)) {
+        return emptyStr;
+    }
+    int32_t resLen=0;
+    const char *curLocaleName=locale.getBaseName();
+    const char16_t* s = ures_getStringByKey(locRes.getAlias(), curLocaleName, &resLen, &errCode);
+
+    if (s == nullptr) {
+        // Check parent locales.
+        UErrorCode status = U_ZERO_ERROR;
+        char parentLocaleName[ULOC_FULLNAME_CAPACITY];
+        const char *curLocaleName2=locale.getBaseName();
+        uprv_strcpy(parentLocaleName, curLocaleName2);
+
+        while (uloc_getParent(parentLocaleName, parentLocaleName,
+                                       ULOC_FULLNAME_CAPACITY, &status) > 0) {
+            resLen=0;
+            s = ures_getStringByKey(locRes.getAlias(), parentLocaleName, &resLen, &status);
+            if (s != nullptr) {
+                errCode = U_ZERO_ERROR;
+                break;
+            }
+            status = U_ZERO_ERROR;
+        }
+    }
+    if (s==nullptr) {
+        return emptyStr;
+    }
+
+    char setKey[256];
+    u_UCharsToChars(s, setKey, resLen + 1);
+    // printf("\n PluralRule: %s\n", setKey);
+
+    LocalUResourceBundlePointer ruleRes(ures_getByKey(rb.getAlias(), "rules", nullptr, &errCode));
+    if(U_FAILURE(errCode)) {
+        return emptyStr;
+    }
+    LocalUResourceBundlePointer setRes(ures_getByKey(ruleRes.getAlias(), setKey, nullptr, &errCode));
+    if (U_FAILURE(errCode)) {
+        return emptyStr;
+    }
+
+    int32_t numberKeys = ures_getSize(setRes.getAlias());
+    UnicodeString result;
+    const char *key=nullptr;
+    for(int32_t i=0; i<numberKeys; ++i) {   // Keys are zero, one, few, ...
+        UnicodeString rules = ures_getNextUnicodeString(setRes.getAlias(), &key, &errCode);
+        UnicodeString uKey(key, -1, US_INV);
+        result.append(uKey);
+        result.append(COLON);
+        result.append(rules);
+        result.append(SEMI_COLON);
+    }
+    return result;
+}
+
+
+UnicodeString
+PluralRules::getRules() const {
+    UnicodeString rules;
+    if (mRules != nullptr) {
+        mRules->dumpRules(rules);
+    }
+    return rules;
+}
+
+AndConstraint::AndConstraint(const AndConstraint& other) {
+    this->fInternalStatus = other.fInternalStatus;
+    if (U_FAILURE(fInternalStatus)) {
+        return; // stop early if the object we are copying from is invalid.
+    }
+    this->op = other.op;
+    this->opNum=other.opNum;
+    this->value=other.value;
+    if (other.rangeList != nullptr) {
+        LocalPointer<UVector32> newRangeList(new UVector32(fInternalStatus), fInternalStatus);
+        if (U_FAILURE(fInternalStatus)) {
+            return;
+        }
+        this->rangeList = newRangeList.orphan();
+        this->rangeList->assign(*other.rangeList, fInternalStatus);
+    }
+    this->integerOnly=other.integerOnly;
+    this->negated=other.negated;
+    this->digitsType = other.digitsType;
+    if (other.next != nullptr) {
+        this->next = new AndConstraint(*other.next);
+        if (this->next == nullptr) {
+            fInternalStatus = U_MEMORY_ALLOCATION_ERROR;
+        }
+    }
+}
+
+AndConstraint::~AndConstraint() {
+    delete rangeList;
+    rangeList = nullptr;
+    delete next;
+    next = nullptr;
+}
+
+UBool
+AndConstraint::isFulfilled(const IFixedDecimal &number) {
+    UBool result = true;
+    if (digitsType == none) {
+        // An empty AndConstraint, created by a rule with a keyword but no following expression.
+        return true;
+    }
+
+    PluralOperand operand = tokenTypeToPluralOperand(digitsType);
+    double n = number.getPluralOperand(operand);     // pulls n | i | v | f value for the number.
+                                                     // Will always be positive.
+                                                     // May be non-integer (n option only)
+    do {
+        if (integerOnly && n != uprv_floor(n)) {
+            result = false;
+            break;
+        }
+
+        if (op == MOD) {
+            n = fmod(n, opNum);
+        }
+        if (rangeList == nullptr) {
+            result = value == -1 ||    // empty rule
+                     n == value;       //  'is' rule
+            break;
+        }
+        result = false;                // 'in' or 'within' rule
+        for (int32_t r=0; r<rangeList->size(); r+=2) {
+            if (rangeList->elementAti(r) <= n && n <= rangeList->elementAti(r+1)) {
+                result = true;
+                break;
+            }
+        }
+    } while (false);
+
+    if (negated) {
+        result = !result;
+    }
+    return result;
+}
+
+AndConstraint*
+AndConstraint::add(UErrorCode& status) {
+    if (U_FAILURE(fInternalStatus)) {
+        status = fInternalStatus;
+        return nullptr;
+    }
+    this->next = new AndConstraint();
+    if (this->next == nullptr) {
+        status = U_MEMORY_ALLOCATION_ERROR;
+    }
+    return this->next;
+}
+
+
+OrConstraint::OrConstraint(const OrConstraint& other) {
+    this->fInternalStatus = other.fInternalStatus;
+    if (U_FAILURE(fInternalStatus)) {
+        return; // stop early if the object we are copying from is invalid.
+    }
+    if ( other.childNode != nullptr ) {
+        this->childNode = new AndConstraint(*(other.childNode));
+        if (this->childNode == nullptr) {
+            fInternalStatus = U_MEMORY_ALLOCATION_ERROR;
+            return;
+        }
+    }
+    if (other.next != nullptr ) {
+        this->next = new OrConstraint(*(other.next));
+        if (this->next == nullptr) {
+            fInternalStatus = U_MEMORY_ALLOCATION_ERROR;
+            return;
+        }
+        if (U_FAILURE(this->next->fInternalStatus)) {
+            this->fInternalStatus = this->next->fInternalStatus;
+        }
+    }
+}
+
+OrConstraint::~OrConstraint() {
+    delete childNode;
+    childNode = nullptr;
+    delete next;
+    next = nullptr;
+}
+
+AndConstraint*
+OrConstraint::add(UErrorCode& status) {
+    if (U_FAILURE(fInternalStatus)) {
+        status = fInternalStatus;
+        return nullptr;
+    }
+    OrConstraint *curOrConstraint=this;
+    {
+        while (curOrConstraint->next!=nullptr) {
+            curOrConstraint = curOrConstraint->next;
+        }
+        U_ASSERT(curOrConstraint->childNode == nullptr);
+        curOrConstraint->childNode = new AndConstraint();
+        if (curOrConstraint->childNode == nullptr) {
+            status = U_MEMORY_ALLOCATION_ERROR;
+        }
+    }
+    return curOrConstraint->childNode;
+}
+
+UBool
+OrConstraint::isFulfilled(const IFixedDecimal &number) {
+    OrConstraint* orRule=this;
+    UBool result=false;
+
+    while (orRule!=nullptr && !result) {
+        result=true;
+        AndConstraint* andRule = orRule->childNode;
+        while (andRule!=nullptr && result) {
+            result = andRule->isFulfilled(number);
+            andRule=andRule->next;
+        }
+        orRule = orRule->next;
+    }
+
+    return result;
+}
+
+
+RuleChain::RuleChain(const RuleChain& other) :
+        fKeyword(other.fKeyword), fDecimalSamples(other.fDecimalSamples),
+        fIntegerSamples(other.fIntegerSamples), fDecimalSamplesUnbounded(other.fDecimalSamplesUnbounded),
+        fIntegerSamplesUnbounded(other.fIntegerSamplesUnbounded), fInternalStatus(other.fInternalStatus) {
+    if (U_FAILURE(this->fInternalStatus)) {
+        return; // stop early if the object we are copying from is invalid. 
+    }
+    if (other.ruleHeader != nullptr) {
+        this->ruleHeader = new OrConstraint(*(other.ruleHeader));
+        if (this->ruleHeader == nullptr) {
+            this->fInternalStatus = U_MEMORY_ALLOCATION_ERROR;
+        }
+        else if (U_FAILURE(this->ruleHeader->fInternalStatus)) {
+            // If the OrConstraint wasn't fully copied, then set our status to failure as well.
+            this->fInternalStatus = this->ruleHeader->fInternalStatus;
+            return; // exit early.
+        }
+    }
+    if (other.fNext != nullptr ) {
+        this->fNext = new RuleChain(*other.fNext);
+        if (this->fNext == nullptr) {
+            this->fInternalStatus = U_MEMORY_ALLOCATION_ERROR;
+        }
+        else if (U_FAILURE(this->fNext->fInternalStatus)) {
+            // If the RuleChain wasn't fully copied, then set our status to failure as well.
+            this->fInternalStatus = this->fNext->fInternalStatus;
+        }
+    }
+}
+
+RuleChain::~RuleChain() {
+    delete fNext;
+    delete ruleHeader;
+}
+
+UnicodeString
+RuleChain::select(const IFixedDecimal &number) const {
+    if (!number.isNaN() && !number.isInfinite()) {
+        for (const RuleChain *rules = this; rules != nullptr; rules = rules->fNext) {
+             if (rules->ruleHeader->isFulfilled(number)) {
+                 return rules->fKeyword;
+             }
+        }
+    }
+    return UnicodeString(true, PLURAL_KEYWORD_OTHER, 5);
+}
+
+static UnicodeString tokenString(tokenType tok) {
+    UnicodeString s;
+    switch (tok) {
+      case tVariableN:
+        s.append(LOW_N); break;
+      case tVariableI:
+        s.append(LOW_I); break;
+      case tVariableF:
+        s.append(LOW_F); break;
+      case tVariableV:
+        s.append(LOW_V); break;
+      case tVariableT:
+        s.append(LOW_T); break;
+      case tVariableE:
+        s.append(LOW_E); break;
+    case tVariableC:
+        s.append(LOW_C); break;
+      default:
+        s.append(TILDE);
+    }
+    return s;
+}
+
+void
+RuleChain::dumpRules(UnicodeString& result) {
+    char16_t digitString[16];
+
+    if ( ruleHeader != nullptr ) {
+        result +=  fKeyword;
+        result += COLON;
+        result += SPACE;
+        OrConstraint* orRule=ruleHeader;
+        while ( orRule != nullptr ) {
+            AndConstraint* andRule=orRule->childNode;
+            while ( andRule != nullptr ) {
+                if ((andRule->op==AndConstraint::NONE) &&  (andRule->rangeList==nullptr) && (andRule->value == -1)) {
+                    // Empty Rules.
+                } else if ( (andRule->op==AndConstraint::NONE) && (andRule->rangeList==nullptr) ) {
+                    result += tokenString(andRule->digitsType);
+                    result += UNICODE_STRING_SIMPLE(" is ");
+                    if (andRule->negated) {
+                        result += UNICODE_STRING_SIMPLE("not ");
+                    }
+                    uprv_itou(digitString,16, andRule->value,10,0);
+                    result += UnicodeString(digitString);
+                }
+                else {
+                    result += tokenString(andRule->digitsType);
+                    result += SPACE;
+                    if (andRule->op==AndConstraint::MOD) {
+                        result += UNICODE_STRING_SIMPLE("mod ");
+                        uprv_itou(digitString,16, andRule->opNum,10,0);
+                        result += UnicodeString(digitString);
+                    }
+                    if (andRule->rangeList==nullptr) {
+                        if (andRule->negated) {
+                            result += UNICODE_STRING_SIMPLE(" is not ");
+                            uprv_itou(digitString,16, andRule->value,10,0);
+                            result += UnicodeString(digitString);
+                        }
+                        else {
+                            result += UNICODE_STRING_SIMPLE(" is ");
+                            uprv_itou(digitString,16, andRule->value,10,0);
+                            result += UnicodeString(digitString);
+                        }
+                    }
+                    else {
+                        if (andRule->negated) {
+                            if ( andRule->integerOnly ) {
+                                result += UNICODE_STRING_SIMPLE(" not in ");
+                            }
+                            else {
+                                result += UNICODE_STRING_SIMPLE(" not within ");
+                            }
+                        }
+                        else {
+                            if ( andRule->integerOnly ) {
+                                result += UNICODE_STRING_SIMPLE(" in ");
+                            }
+                            else {
+                                result += UNICODE_STRING_SIMPLE(" within ");
+                            }
+                        }
+                        for (int32_t r=0; r<andRule->rangeList->size(); r+=2) {
+                            int32_t rangeLo = andRule->rangeList->elementAti(r);
+                            int32_t rangeHi = andRule->rangeList->elementAti(r+1);
+                            uprv_itou(digitString,16, rangeLo, 10, 0);
+                            result += UnicodeString(digitString);
+                            result += UNICODE_STRING_SIMPLE("..");
+                            uprv_itou(digitString,16, rangeHi, 10,0);
+                            result += UnicodeString(digitString);
+                            if (r+2 < andRule->rangeList->size()) {
+                                result += UNICODE_STRING_SIMPLE(", ");
+                            }
+                        }
+                    }
+                }
+                if ( (andRule=andRule->next) != nullptr) {
+                    result += UNICODE_STRING_SIMPLE(" and ");
+                }
+            }
+            if ( (orRule = orRule->next) != nullptr ) {
+                result += UNICODE_STRING_SIMPLE(" or ");
+            }
+        }
+    }
+    if ( fNext != nullptr ) {
+        result += UNICODE_STRING_SIMPLE("; ");
+        fNext->dumpRules(result);
+    }
+}
+
+
+UErrorCode
+RuleChain::getKeywords(int32_t capacityOfKeywords, UnicodeString* keywords, int32_t& arraySize) const {
+    if (U_FAILURE(fInternalStatus)) {
+        return fInternalStatus;
+    }
+    if ( arraySize < capacityOfKeywords-1 ) {
+        keywords[arraySize++]=fKeyword;
+    }
+    else {
+        return U_BUFFER_OVERFLOW_ERROR;
+    }
+
+    if ( fNext != nullptr ) {
+        return fNext->getKeywords(capacityOfKeywords, keywords, arraySize);
+    }
+    else {
+        return U_ZERO_ERROR;
+    }
+}
+
+UBool
+RuleChain::isKeyword(const UnicodeString& keywordParam) const {
+    if ( fKeyword == keywordParam ) {
+        return true;
+    }
+
+    if ( fNext != nullptr ) {
+        return fNext->isKeyword(keywordParam);
+    }
+    else {
+        return false;
+    }
+}
+
+
+PluralRuleParser::PluralRuleParser() :
+        ruleIndex(0), token(), type(none), prevType(none),
+        curAndConstraint(nullptr), currentChain(nullptr), rangeLowIdx(-1), rangeHiIdx(-1)
+{
+}
+
+PluralRuleParser::~PluralRuleParser() {
+}
+
+
+int32_t
+PluralRuleParser::getNumberValue(const UnicodeString& token) {
+    int32_t i;
+    char digits[128];
+
+    i = token.extract(0, token.length(), digits, UPRV_LENGTHOF(digits), US_INV);
+    digits[i]='\0';
+
+    return((int32_t)atoi(digits));
+}
+
+
+void
+PluralRuleParser::checkSyntax(UErrorCode &status)
+{
+    if (U_FAILURE(status)) {
+        return;
+    }
+    if (!(prevType==none || prevType==tSemiColon)) {
+        type = getKeyType(token, type);  // Switch token type from tKeyword if we scanned a reserved word,
+                                               //   and we are not at the start of a rule, where a
+                                               //   keyword is expected.
+    }
+
+    switch(prevType) {
+    case none:
+    case tSemiColon:
+        if (type!=tKeyword && type != tEOF) {
+            status = U_UNEXPECTED_TOKEN;
+        }
+        break;
+    case tVariableN:
+    case tVariableI:
+    case tVariableF:
+    case tVariableT:
+    case tVariableE:
+    case tVariableC:
+    case tVariableV:
+        if (type != tIs && type != tMod && type != tIn &&
+            type != tNot && type != tWithin && type != tEqual && type != tNotEqual) {
+            status = U_UNEXPECTED_TOKEN;
+        }
+        break;
+    case tKeyword:
+        if (type != tColon) {
+            status = U_UNEXPECTED_TOKEN;
+        }
+        break;
+    case tColon:
+        if (!(type == tVariableN ||
+              type == tVariableI ||
+              type == tVariableF ||
+              type == tVariableT ||
+              type == tVariableE ||
+              type == tVariableC ||
+              type == tVariableV ||
+              type == tAt)) {
+            status = U_UNEXPECTED_TOKEN;
+        }
+        break;
+    case tIs:
+        if ( type != tNumber && type != tNot) {
+            status = U_UNEXPECTED_TOKEN;
+        }
+        break;
+    case tNot:
+        if (type != tNumber && type != tIn && type != tWithin) {
+            status = U_UNEXPECTED_TOKEN;
+        }
+        break;
+    case tMod:
+    case tDot2:
+    case tIn:
+    case tWithin:
+    case tEqual:
+    case tNotEqual:
+        if (type != tNumber) {
+            status = U_UNEXPECTED_TOKEN;
+        }
+        break;
+    case tAnd:
+    case tOr:
+        if ( type != tVariableN &&
+             type != tVariableI &&
+             type != tVariableF &&
+             type != tVariableT &&
+             type != tVariableE &&
+             type != tVariableC &&
+             type != tVariableV) {
+            status = U_UNEXPECTED_TOKEN;
+        }
+        break;
+    case tComma:
+        if (type != tNumber) {
+            status = U_UNEXPECTED_TOKEN;
+        }
+        break;
+    case tNumber:
+        if (type != tDot2  && type != tSemiColon && type != tIs       && type != tNot    &&
+            type != tIn    && type != tEqual     && type != tNotEqual && type != tWithin &&
+            type != tAnd   && type != tOr        && type != tComma    && type != tAt     &&
+            type != tEOF)
+        {
+            status = U_UNEXPECTED_TOKEN;
+        }
+        // TODO: a comma following a number that is not part of a range will be allowed.
+        //       It's not the only case of this sort of thing. Parser needs a re-write.
+        break;
+    case tAt:
+        if (type != tDecimal && type != tInteger) {
+            status = U_UNEXPECTED_TOKEN;
+        }
+        break;
+    default:
+        status = U_UNEXPECTED_TOKEN;
+        break;
+    }
+}
+
+
+/*
+ *  Scan the next token from the input rules.
+ *     rules and returned token type are in the parser state variables.
+ */
+void
+PluralRuleParser::getNextToken(UErrorCode &status)
+{
+    if (U_FAILURE(status)) {
+        return;
+    }
+
+    char16_t ch;
+    while (ruleIndex < ruleSrc->length()) {
+        ch = ruleSrc->charAt(ruleIndex);
+        type = charType(ch);
+        if (type != tSpace) {
+            break;
+        }
+        ++(ruleIndex);
+    }
+    if (ruleIndex >= ruleSrc->length()) {
+        type = tEOF;
+        return;
+    }
+    int32_t curIndex= ruleIndex;
+
+    switch (type) {
+      case tColon:
+      case tSemiColon:
+      case tComma:
+      case tEllipsis:
+      case tTilde:   // scanned '~'
+      case tAt:      // scanned '@'
+      case tEqual:   // scanned '='
+      case tMod:     // scanned '%'
+        // Single character tokens.
+        ++curIndex;
+        break;
+
+      case tNotEqual:  // scanned '!'
+        if (ruleSrc->charAt(curIndex+1) == EQUALS) {
+            curIndex += 2;
+        } else {
+            type = none;
+            curIndex += 1;
+        }
+        break;
+
+      case tKeyword:
+         while (type == tKeyword && ++curIndex < ruleSrc->length()) {
+             ch = ruleSrc->charAt(curIndex);
+             type = charType(ch);
+         }
+         type = tKeyword;
+         break;
+
+      case tNumber:
+         while (type == tNumber && ++curIndex < ruleSrc->length()) {
+             ch = ruleSrc->charAt(curIndex);
+             type = charType(ch);
+         }
+         type = tNumber;
+         break;
+
+       case tDot:
+         // We could be looking at either ".." in a range, or "..." at the end of a sample.
+         if (curIndex+1 >= ruleSrc->length() || ruleSrc->charAt(curIndex+1) != DOT) {
+             ++curIndex;
+             break; // Single dot
+         }
+         if (curIndex+2 >= ruleSrc->length() || ruleSrc->charAt(curIndex+2) != DOT) {
+             curIndex += 2;
+             type = tDot2;
+             break; // double dot
+         }
+         type = tEllipsis;
+         curIndex += 3;
+         break;     // triple dot
+
+       default:
+         status = U_UNEXPECTED_TOKEN;
+         ++curIndex;
+         break;
+    }
+
+    U_ASSERT(ruleIndex <= ruleSrc->length());
+    U_ASSERT(curIndex <= ruleSrc->length());
+    token=UnicodeString(*ruleSrc, ruleIndex, curIndex-ruleIndex);
+    ruleIndex = curIndex;
+}
+
+tokenType
+PluralRuleParser::charType(char16_t ch) {
+    if ((ch>=U_ZERO) && (ch<=U_NINE)) {
+        return tNumber;
+    }
+    if (ch>=LOW_A && ch<=LOW_Z) {
+        return tKeyword;
+    }
+    switch (ch) {
+    case COLON:
+        return tColon;
+    case SPACE:
+        return tSpace;
+    case SEMI_COLON:
+        return tSemiColon;
+    case DOT:
+        return tDot;
+    case COMMA:
+        return tComma;
+    case EXCLAMATION:
+        return tNotEqual;
+    case EQUALS:
+        return tEqual;
+    case PERCENT_SIGN:
+        return tMod;
+    case AT:
+        return tAt;
+    case ELLIPSIS:
+        return tEllipsis;
+    case TILDE:
+        return tTilde;
+    default :
+        return none;
+    }
+}
+
+
+//  Set token type for reserved words in the Plural Rule syntax.
+
+tokenType
+PluralRuleParser::getKeyType(const UnicodeString &token, tokenType keyType)
+{
+    if (keyType != tKeyword) {
+        return keyType;
+    }
+
+    if (0 == token.compare(PK_VAR_N, 1)) {
+        keyType = tVariableN;
+    } else if (0 == token.compare(PK_VAR_I, 1)) {
+        keyType = tVariableI;
+    } else if (0 == token.compare(PK_VAR_F, 1)) {
+        keyType = tVariableF;
+    } else if (0 == token.compare(PK_VAR_T, 1)) {
+        keyType = tVariableT;
+    } else if (0 == token.compare(PK_VAR_E, 1)) {
+        keyType = tVariableE;
+    } else if (0 == token.compare(PK_VAR_C, 1)) {
+        keyType = tVariableC;
+    } else if (0 == token.compare(PK_VAR_V, 1)) {
+        keyType = tVariableV;
+    } else if (0 == token.compare(PK_IS, 2)) {
+        keyType = tIs;
+    } else if (0 == token.compare(PK_AND, 3)) {
+        keyType = tAnd;
+    } else if (0 == token.compare(PK_IN, 2)) {
+        keyType = tIn;
+    } else if (0 == token.compare(PK_WITHIN, 6)) {
+        keyType = tWithin;
+    } else if (0 == token.compare(PK_NOT, 3)) {
+        keyType = tNot;
+    } else if (0 == token.compare(PK_MOD, 3)) {
+        keyType = tMod;
+    } else if (0 == token.compare(PK_OR, 2)) {
+        keyType = tOr;
+    } else if (0 == token.compare(PK_DECIMAL, 7)) {
+        keyType = tDecimal;
+    } else if (0 == token.compare(PK_INTEGER, 7)) {
+        keyType = tInteger;
+    }
+    return keyType;
+}
+
+
+PluralKeywordEnumeration::PluralKeywordEnumeration(RuleChain *header, UErrorCode& status)
+        : pos(0), fKeywordNames(status) {
+    if (U_FAILURE(status)) {
+        return;
+    }
+    fKeywordNames.setDeleter(uprv_deleteUObject);
+    UBool  addKeywordOther = true;
+    RuleChain *node = header;
+    while (node != nullptr) {
+        LocalPointer<UnicodeString> newElem(node->fKeyword.clone(), status);
+        fKeywordNames.adoptElement(newElem.orphan(), status);
+        if (U_FAILURE(status)) {
+            return;
+        }
+        if (0 == node->fKeyword.compare(PLURAL_KEYWORD_OTHER, 5)) {
+            addKeywordOther = false;
+        }
+        node = node->fNext;
+    }
+
+    if (addKeywordOther) {
+        LocalPointer<UnicodeString> newElem(new UnicodeString(PLURAL_KEYWORD_OTHER), status);
+        fKeywordNames.adoptElement(newElem.orphan(), status);
+        if (U_FAILURE(status)) {
+            return;
+        }
+    }
+}
+
+const UnicodeString*
+PluralKeywordEnumeration::snext(UErrorCode& status) {
+    if (U_SUCCESS(status) && pos < fKeywordNames.size()) {
+        return (const UnicodeString*)fKeywordNames.elementAt(pos++);
+    }
+    return nullptr;
+}
+
+void
+PluralKeywordEnumeration::reset(UErrorCode& /*status*/) {
+    pos=0;
+}
+
+int32_t
+PluralKeywordEnumeration::count(UErrorCode& /*status*/) const {
+    return fKeywordNames.size();
+}
+
+PluralKeywordEnumeration::~PluralKeywordEnumeration() {
+}
+
+PluralOperand tokenTypeToPluralOperand(tokenType tt) {
+    switch(tt) {
+    case tVariableN:
+        return PLURAL_OPERAND_N;
+    case tVariableI:
+        return PLURAL_OPERAND_I;
+    case tVariableF:
+        return PLURAL_OPERAND_F;
+    case tVariableV:
+        return PLURAL_OPERAND_V;
+    case tVariableT:
+        return PLURAL_OPERAND_T;
+    case tVariableE:
+        return PLURAL_OPERAND_E;
+    case tVariableC:
+        return PLURAL_OPERAND_E;
+    default:
+        UPRV_UNREACHABLE_EXIT;  // unexpected.
+    }
+}
+
+FixedDecimal::FixedDecimal(double n, int32_t v, int64_t f, int32_t e, int32_t c) {
+    init(n, v, f, e, c);
+}
+
+FixedDecimal::FixedDecimal(double n, int32_t v, int64_t f, int32_t e) {
+    init(n, v, f, e);
+    // check values. TODO make into unit test.
+    //            
+    //            long visiblePower = (int) Math.pow(10.0, v);
+    //            if (decimalDigits > visiblePower) {
+    //                throw new IllegalArgumentException();
+    //            }
+    //            double fraction = intValue + (decimalDigits / (double) visiblePower);
+    //            if (fraction != source) {
+    //                double diff = Math.abs(fraction - source)/(Math.abs(fraction) + Math.abs(source));
+    //                if (diff > 0.00000001d) {
+    //                    throw new IllegalArgumentException();
+    //                }
+    //            }
+}
+
+FixedDecimal::FixedDecimal(double n, int32_t v, int64_t f) {
+    init(n, v, f);
+}
+
+FixedDecimal::FixedDecimal(double n, int32_t v) {
+    // Ugly, but for samples we don't care.
+    init(n, v, getFractionalDigits(n, v));
+}
+
+FixedDecimal::FixedDecimal(double n) {
+    init(n);
+}
+
+FixedDecimal::FixedDecimal() {
+    init(0, 0, 0);
+}
+
+
+// Create a FixedDecimal from a UnicodeString containing a number.
+//    Inefficient, but only used for samples, so simplicity trumps efficiency.
+
+FixedDecimal::FixedDecimal(const UnicodeString &num, UErrorCode &status) {
+    CharString cs;
+    int32_t parsedExponent = 0;
+    int32_t parsedCompactExponent = 0;
+
+    int32_t exponentIdx = num.indexOf(u'e');
+    if (exponentIdx < 0) {
+        exponentIdx = num.indexOf(u'E');
+    }
+    int32_t compactExponentIdx = num.indexOf(u'c');
+    if (compactExponentIdx < 0) {
+        compactExponentIdx = num.indexOf(u'C');
+    }
+
+    if (exponentIdx >= 0) {
+        cs.appendInvariantChars(num.tempSubString(0, exponentIdx), status);
+        int32_t expSubstrStart = exponentIdx + 1;
+        parsedExponent = ICU_Utility::parseAsciiInteger(num, expSubstrStart);
+    }
+    else if (compactExponentIdx >= 0) {
+        cs.appendInvariantChars(num.tempSubString(0, compactExponentIdx), status);
+        int32_t expSubstrStart = compactExponentIdx + 1;
+        parsedCompactExponent = ICU_Utility::parseAsciiInteger(num, expSubstrStart);
+
+        parsedExponent = parsedCompactExponent;
+        exponentIdx = compactExponentIdx;
+    }
+    else {
+        cs.appendInvariantChars(num, status);
+    }
+
+    DecimalQuantity dl;
+    dl.setToDecNumber(cs.toStringPiece(), status);
+    if (U_FAILURE(status)) {
+        init(0, 0, 0);
+        return;
+    }
+
+    int32_t decimalPoint = num.indexOf(DOT);
+    double n = dl.toDouble();
+    if (decimalPoint == -1) {
+        init(n, 0, 0, parsedExponent);
+    } else {
+        int32_t fractionNumLength = exponentIdx < 0 ? num.length() : cs.length();
+        int32_t v = fractionNumLength - decimalPoint - 1;
+        init(n, v, getFractionalDigits(n, v), parsedExponent);
+    }
+}
+
+
+FixedDecimal::FixedDecimal(const FixedDecimal &other) {
+    source = other.source;
+    visibleDecimalDigitCount = other.visibleDecimalDigitCount;
+    decimalDigits = other.decimalDigits;
+    decimalDigitsWithoutTrailingZeros = other.decimalDigitsWithoutTrailingZeros;
+    intValue = other.intValue;
+    exponent = other.exponent;
+    _hasIntegerValue = other._hasIntegerValue;
+    isNegative = other.isNegative;
+    _isNaN = other._isNaN;
+    _isInfinite = other._isInfinite;
+}
+
+FixedDecimal::~FixedDecimal() = default;
+
+FixedDecimal FixedDecimal::createWithExponent(double n, int32_t v, int32_t e) {
+    return FixedDecimal(n, v, getFractionalDigits(n, v), e);
+}
+
+
+void FixedDecimal::init(double n) {
+    int32_t numFractionDigits = decimals(n);
+    init(n, numFractionDigits, getFractionalDigits(n, numFractionDigits));
+}
+
+
+void FixedDecimal::init(double n, int32_t v, int64_t f) {
+    int32_t exponent = 0;
+    init(n, v, f, exponent);
+}
+
+void FixedDecimal::init(double n, int32_t v, int64_t f, int32_t e) {
+    // Currently, `c` is an alias for `e`
+    init(n, v, f, e, e);
+}
+
+void FixedDecimal::init(double n, int32_t v, int64_t f, int32_t e, int32_t c) {
+    isNegative = n < 0.0;
+    source = fabs(n);
+    _isNaN = uprv_isNaN(source);
+    _isInfinite = uprv_isInfinite(source);
+    exponent = e;
+    if (exponent == 0) {
+        exponent = c;
+    }
+    if (_isNaN || _isInfinite) {
+        v = 0;
+        f = 0;
+        intValue = 0;
+        _hasIntegerValue = false;
+    } else {
+        intValue = (int64_t)source;
+        _hasIntegerValue = (source == intValue);
+    }
+
+    visibleDecimalDigitCount = v;
+    decimalDigits = f;
+    if (f == 0) {
+         decimalDigitsWithoutTrailingZeros = 0;
+    } else {
+        int64_t fdwtz = f;
+        while ((fdwtz%10) == 0) {
+            fdwtz /= 10;
+        }
+        decimalDigitsWithoutTrailingZeros = fdwtz;
+    }
+}
+
+
+//  Fast path only exact initialization. Return true if successful.
+//     Note: Do not multiply by 10 each time through loop, rounding cruft can build
+//           up that makes the check for an integer result fail.
+//           A single multiply of the original number works more reliably.
+static int32_t p10[] = {1, 10, 100, 1000, 10000};
+UBool FixedDecimal::quickInit(double n) {
+    UBool success = false;
+    n = fabs(n);
+    int32_t numFractionDigits;
+    for (numFractionDigits = 0; numFractionDigits <= 3; numFractionDigits++) {
+        double scaledN = n * p10[numFractionDigits];
+        if (scaledN == floor(scaledN)) {
+            success = true;
+            break;
+        }
+    }
+    if (success) {
+        init(n, numFractionDigits, getFractionalDigits(n, numFractionDigits));
+    }
+    return success;
+}
+
+
+
+int32_t FixedDecimal::decimals(double n) {
+    // Count the number of decimal digits in the fraction part of the number, excluding trailing zeros.
+    // fastpath the common cases, integers or fractions with 3 or fewer digits
+    n = fabs(n);
+    for (int ndigits=0; ndigits<=3; ndigits++) {
+        double scaledN = n * p10[ndigits];
+        if (scaledN == floor(scaledN)) {
+            return ndigits;
+        }
+    }
+
+    // Slow path, convert with snprintf, parse converted output.
+    char  buf[30] = {0};
+    snprintf(buf, sizeof(buf), "%1.15e", n);
+    // formatted number looks like this: 1.234567890123457e-01
+    int exponent = atoi(buf+18);
+    int numFractionDigits = 15;
+    for (int i=16; ; --i) {
+        if (buf[i] != '0') {
+            break;
+        }
+        --numFractionDigits;
+    }
+    numFractionDigits -= exponent;   // Fraction part of fixed point representation.
+    return numFractionDigits;
+}
+
+
+// Get the fraction digits of a double, represented as an integer.
+//    v is the number of visible fraction digits in the displayed form of the number.
+//       Example: n = 1001.234, v = 6, result = 234000
+//    TODO: need to think through how this is used in the plural rule context.
+//          This function can easily encounter integer overflow, 
+//          and can easily return noise digits when the precision of a double is exceeded.
+
+int64_t FixedDecimal::getFractionalDigits(double n, int32_t v) {
+    if (v == 0 || n == floor(n) || uprv_isNaN(n) || uprv_isPositiveInfinity(n)) {
+        return 0;
+    }
+    n = fabs(n);
+    double fract = n - floor(n);
+    switch (v) {
+      case 1: return (int64_t)(fract*10.0 + 0.5);
+      case 2: return (int64_t)(fract*100.0 + 0.5);
+      case 3: return (int64_t)(fract*1000.0 + 0.5);
+      default:
+          double scaled = floor(fract * pow(10.0, (double)v) + 0.5);
+          if (scaled >= static_cast<double>(U_INT64_MAX)) {
+              // Note: a double cannot accurately represent U_INT64_MAX. Casting it to double
+              //       will round up to the next representable value, which is U_INT64_MAX + 1.
+              return U_INT64_MAX;
+          } else {
+              return (int64_t)scaled;
+          }
+      }
+}
+
+
+void FixedDecimal::adjustForMinFractionDigits(int32_t minFractionDigits) {
+    int32_t numTrailingFractionZeros = minFractionDigits - visibleDecimalDigitCount;
+    if (numTrailingFractionZeros > 0) {
+        for (int32_t i=0; i<numTrailingFractionZeros; i++) {
+            // Do not let the decimalDigits value overflow if there are many trailing zeros.
+            // Limit the value to 18 digits, the most that a 64 bit int can fully represent.
+            if (decimalDigits >= 100000000000000000LL) {
+                break;
+            }
+            decimalDigits *= 10;
+        }
+        visibleDecimalDigitCount += numTrailingFractionZeros;
+    }
+}
+
+
+double FixedDecimal::getPluralOperand(PluralOperand operand) const {
+    switch(operand) {
+        case PLURAL_OPERAND_N: return (exponent == 0 ? source : source * pow(10.0, exponent));
+        case PLURAL_OPERAND_I: return (double) longValue();
+        case PLURAL_OPERAND_F: return static_cast<double>(decimalDigits);
+        case PLURAL_OPERAND_T: return static_cast<double>(decimalDigitsWithoutTrailingZeros);
+        case PLURAL_OPERAND_V: return visibleDecimalDigitCount;
+        case PLURAL_OPERAND_E: return exponent;
+        case PLURAL_OPERAND_C: return exponent;
+        default:
+             UPRV_UNREACHABLE_EXIT;  // unexpected.
+    }
+}
+
+bool FixedDecimal::isNaN() const {
+    return _isNaN;
+}
+
+bool FixedDecimal::isInfinite() const {
+    return _isInfinite;
+}
+
+bool FixedDecimal::hasIntegerValue() const {
+    return _hasIntegerValue;
+}
+
+bool FixedDecimal::isNanOrInfinity() const {
+    return _isNaN || _isInfinite;
+}
+
+int32_t FixedDecimal::getVisibleFractionDigitCount() const {
+    return visibleDecimalDigitCount;
+}
+
+bool FixedDecimal::operator==(const FixedDecimal &other) const {
+    return source == other.source && visibleDecimalDigitCount == other.visibleDecimalDigitCount
+        && decimalDigits == other.decimalDigits && exponent == other.exponent;
+}
+
+UnicodeString FixedDecimal::toString() const {
+    char pattern[15];
+    char buffer[20];
+    if (exponent != 0) {
+        snprintf(pattern, sizeof(pattern), "%%.%dfe%%d", visibleDecimalDigitCount);
+        snprintf(buffer, sizeof(buffer), pattern, source, exponent);
+    } else {
+        snprintf(pattern, sizeof(pattern), "%%.%df", visibleDecimalDigitCount);
+        snprintf(buffer, sizeof(buffer), pattern, source);
+    }
+    return UnicodeString(buffer, -1, US_INV);
+}
+
+double FixedDecimal::doubleValue() const {
+    return (isNegative ? -source : source) * pow(10.0, exponent);
+}
+
+int64_t FixedDecimal::longValue() const {
+    if (exponent == 0) {
+        return intValue;
+    } else {
+        return (long) (pow(10.0, exponent) * intValue);
+    }
+}
+
+
+PluralAvailableLocalesEnumeration::PluralAvailableLocalesEnumeration(UErrorCode &status) {
+    fOpenStatus = status;
+    if (U_FAILURE(status)) {
+        return;
+    }
+    fOpenStatus = U_ZERO_ERROR; // clear any warnings.
+    LocalUResourceBundlePointer rb(ures_openDirect(nullptr, "plurals", &fOpenStatus));
+    fLocales = ures_getByKey(rb.getAlias(), "locales", nullptr, &fOpenStatus);
+}
+
+PluralAvailableLocalesEnumeration::~PluralAvailableLocalesEnumeration() {
+    ures_close(fLocales);
+    ures_close(fRes);
+    fLocales = nullptr;
+    fRes = nullptr;
+}
+
+const char *PluralAvailableLocalesEnumeration::next(int32_t *resultLength, UErrorCode &status) {
+    if (U_FAILURE(status)) {
+        return nullptr;
+    }
+    if (U_FAILURE(fOpenStatus)) {
+        status = fOpenStatus;
+        return nullptr;
+    }
+    fRes = ures_getNextResource(fLocales, fRes, &status);
+    if (fRes == nullptr || U_FAILURE(status)) {
+        if (status == U_INDEX_OUTOFBOUNDS_ERROR) {
+            status = U_ZERO_ERROR;
+        }
+        return nullptr;
+    }
+    const char *result = ures_getKey(fRes);
+    if (resultLength != nullptr) {
+        *resultLength = static_cast<int32_t>(uprv_strlen(result));
+    }
+    return result;
+}
+
+
+void PluralAvailableLocalesEnumeration::reset(UErrorCode &status) {
+    if (U_FAILURE(status)) {
+       return;
+    }
+    if (U_FAILURE(fOpenStatus)) {
+        status = fOpenStatus;
+        return;
+    }
+    ures_resetIterator(fLocales);
+}
+
+int32_t PluralAvailableLocalesEnumeration::count(UErrorCode &status) const {
+    if (U_FAILURE(status)) {
+        return 0;
+    }
+    if (U_FAILURE(fOpenStatus)) {
+        status = fOpenStatus;
+        return 0;
+    }
+    return ures_getSize(fLocales);
+}
+
+U_NAMESPACE_END
+
+
+#endif /* #if !UCONFIG_NO_FORMATTING */
+
+//eof