Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

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

1 files changed, 2009 insertions, 0 deletions

diff --git a/intl/icu/source/i18n/msgfmt.cpp b/intl/icu/source/i18n/msgfmt.cpp
new file mode 100644
index 0000000000..29fb4b3a01
--- /dev/null
+++ b/intl/icu/source/i18n/msgfmt.cpp
@@ -0,0 +1,2009 @@
+// © 2016 and later: Unicode, Inc. and others.
+// License & terms of use: http://www.unicode.org/copyright.html
+/********************************************************************
+ * COPYRIGHT:
+ * Copyright (c) 1997-2015, International Business Machines Corporation and
+ * others. All Rights Reserved.
+ ********************************************************************
+ *
+ * File MSGFMT.CPP
+ *
+ * Modification History:
+ *
+ *   Date        Name        Description
+ *   02/19/97    aliu        Converted from java.
+ *   03/20/97    helena      Finished first cut of implementation.
+ *   04/10/97    aliu        Made to work on AIX.  Added stoi to replace wtoi.
+ *   06/11/97    helena      Fixed addPattern to take the pattern correctly.
+ *   06/17/97    helena      Fixed the getPattern to return the correct pattern.
+ *   07/09/97    helena      Made ParsePosition into a class.
+ *   02/22/99    stephen     Removed character literals for EBCDIC safety
+ *   11/01/09    kirtig      Added SelectFormat
+ ********************************************************************/
+
+#include "unicode/utypes.h"
+
+#if !UCONFIG_NO_FORMATTING
+
+#include "unicode/appendable.h"
+#include "unicode/choicfmt.h"
+#include "unicode/datefmt.h"
+#include "unicode/decimfmt.h"
+#include "unicode/localpointer.h"
+#include "unicode/msgfmt.h"
+#include "unicode/numberformatter.h"
+#include "unicode/plurfmt.h"
+#include "unicode/rbnf.h"
+#include "unicode/selfmt.h"
+#include "unicode/smpdtfmt.h"
+#include "unicode/umsg.h"
+#include "unicode/ustring.h"
+#include "cmemory.h"
+#include "patternprops.h"
+#include "messageimpl.h"
+#include "msgfmt_impl.h"
+#include "plurrule_impl.h"
+#include "uassert.h"
+#include "uelement.h"
+#include "uhash.h"
+#include "ustrfmt.h"
+#include "util.h"
+#include "uvector.h"
+#include "number_decimalquantity.h"
+
+// *****************************************************************************
+// class MessageFormat
+// *****************************************************************************
+
+#define SINGLE_QUOTE      ((char16_t)0x0027)
+#define COMMA             ((char16_t)0x002C)
+#define LEFT_CURLY_BRACE  ((char16_t)0x007B)
+#define RIGHT_CURLY_BRACE ((char16_t)0x007D)
+
+//---------------------------------------
+// static data
+
+static const char16_t ID_NUMBER[]    = {
+    0x6E, 0x75, 0x6D, 0x62, 0x65, 0x72, 0  /* "number" */
+};
+static const char16_t ID_DATE[]      = {
+    0x64, 0x61, 0x74, 0x65, 0              /* "date" */
+};
+static const char16_t ID_TIME[]      = {
+    0x74, 0x69, 0x6D, 0x65, 0              /* "time" */
+};
+static const char16_t ID_SPELLOUT[]  = {
+    0x73, 0x70, 0x65, 0x6c, 0x6c, 0x6f, 0x75, 0x74, 0 /* "spellout" */
+};
+static const char16_t ID_ORDINAL[]   = {
+    0x6f, 0x72, 0x64, 0x69, 0x6e, 0x61, 0x6c, 0 /* "ordinal" */
+};
+static const char16_t ID_DURATION[]  = {
+    0x64, 0x75, 0x72, 0x61, 0x74, 0x69, 0x6f, 0x6e, 0 /* "duration" */
+};
+
+// MessageFormat Type List  Number, Date, Time or Choice
+static const char16_t * const TYPE_IDS[] = {
+    ID_NUMBER,
+    ID_DATE,
+    ID_TIME,
+    ID_SPELLOUT,
+    ID_ORDINAL,
+    ID_DURATION,
+    nullptr,
+};
+
+static const char16_t ID_EMPTY[]     = {
+    0 /* empty string, used for default so that null can mark end of list */
+};
+static const char16_t ID_CURRENCY[]  = {
+    0x63, 0x75, 0x72, 0x72, 0x65, 0x6E, 0x63, 0x79, 0  /* "currency" */
+};
+static const char16_t ID_PERCENT[]   = {
+    0x70, 0x65, 0x72, 0x63, 0x65, 0x6E, 0x74, 0        /* "percent" */
+};
+static const char16_t ID_INTEGER[]   = {
+    0x69, 0x6E, 0x74, 0x65, 0x67, 0x65, 0x72, 0        /* "integer" */
+};
+
+// NumberFormat modifier list, default, currency, percent or integer
+static const char16_t * const NUMBER_STYLE_IDS[] = {
+    ID_EMPTY,
+    ID_CURRENCY,
+    ID_PERCENT,
+    ID_INTEGER,
+    nullptr,
+};
+
+static const char16_t ID_SHORT[]     = {
+    0x73, 0x68, 0x6F, 0x72, 0x74, 0        /* "short" */
+};
+static const char16_t ID_MEDIUM[]    = {
+    0x6D, 0x65, 0x64, 0x69, 0x75, 0x6D, 0  /* "medium" */
+};
+static const char16_t ID_LONG[]      = {
+    0x6C, 0x6F, 0x6E, 0x67, 0              /* "long" */
+};
+static const char16_t ID_FULL[]      = {
+    0x66, 0x75, 0x6C, 0x6C, 0              /* "full" */
+};
+
+// DateFormat modifier list, default, short, medium, long or full
+static const char16_t * const DATE_STYLE_IDS[] = {
+    ID_EMPTY,
+    ID_SHORT,
+    ID_MEDIUM,
+    ID_LONG,
+    ID_FULL,
+    nullptr,
+};
+
+static const icu::DateFormat::EStyle DATE_STYLES[] = {
+    icu::DateFormat::kDefault,
+    icu::DateFormat::kShort,
+    icu::DateFormat::kMedium,
+    icu::DateFormat::kLong,
+    icu::DateFormat::kFull,
+};
+
+static const int32_t DEFAULT_INITIAL_CAPACITY = 10;
+
+static const char16_t NULL_STRING[] = {
+    0x6E, 0x75, 0x6C, 0x6C, 0  // "null"
+};
+
+static const char16_t OTHER_STRING[] = {
+    0x6F, 0x74, 0x68, 0x65, 0x72, 0  // "other"
+};
+
+U_CDECL_BEGIN
+static UBool U_CALLCONV equalFormatsForHash(const UHashTok key1,
+                                            const UHashTok key2) {
+    return icu::MessageFormat::equalFormats(key1.pointer, key2.pointer);
+}
+
+U_CDECL_END
+
+U_NAMESPACE_BEGIN
+
+// -------------------------------------
+UOBJECT_DEFINE_RTTI_IMPLEMENTATION(MessageFormat)
+UOBJECT_DEFINE_RTTI_IMPLEMENTATION(FormatNameEnumeration)
+
+//--------------------------------------------------------------------
+
+/**
+ * Convert an integer value to a string and append the result to
+ * the given UnicodeString.
+ */
+static UnicodeString& itos(int32_t i, UnicodeString& appendTo) {
+    char16_t temp[16];
+    uprv_itou(temp,16,i,10,0); // 10 == radix
+    appendTo.append(temp, -1);
+    return appendTo;
+}
+
+
+// AppendableWrapper: encapsulates the result of formatting, keeping track
+// of the string and its length.
+class AppendableWrapper : public UMemory {
+public:
+    AppendableWrapper(Appendable& appendable) : app(appendable), len(0) {
+    }
+    void append(const UnicodeString& s) {
+        app.appendString(s.getBuffer(), s.length());
+        len += s.length();
+    }
+    void append(const char16_t* s, const int32_t sLength) {
+        app.appendString(s, sLength);
+        len += sLength;
+    }
+    void append(const UnicodeString& s, int32_t start, int32_t length) {
+        append(s.tempSubString(start, length));
+    }
+    void formatAndAppend(const Format* formatter, const Formattable& arg, UErrorCode& ec) {
+        UnicodeString s;
+        formatter->format(arg, s, ec);
+        if (U_SUCCESS(ec)) {
+            append(s);
+        }
+    }
+    void formatAndAppend(const Format* formatter, const Formattable& arg,
+                         const UnicodeString &argString, UErrorCode& ec) {
+        if (!argString.isEmpty()) {
+            if (U_SUCCESS(ec)) {
+                append(argString);
+            }
+        } else {
+            formatAndAppend(formatter, arg, ec);
+        }
+    }
+    int32_t length() {
+        return len;
+    }
+private:
+    Appendable& app;
+    int32_t len;
+};
+
+
+// -------------------------------------
+// Creates a MessageFormat instance based on the pattern.
+
+MessageFormat::MessageFormat(const UnicodeString& pattern,
+                             UErrorCode& success)
+: fLocale(Locale::getDefault()),  // Uses the default locale
+  msgPattern(success),
+  formatAliases(nullptr),
+  formatAliasesCapacity(0),
+  argTypes(nullptr),
+  argTypeCount(0),
+  argTypeCapacity(0),
+  hasArgTypeConflicts(false),
+  defaultNumberFormat(nullptr),
+  defaultDateFormat(nullptr),
+  cachedFormatters(nullptr),
+  customFormatArgStarts(nullptr),
+  pluralProvider(*this, UPLURAL_TYPE_CARDINAL),
+  ordinalProvider(*this, UPLURAL_TYPE_ORDINAL)
+{
+    setLocaleIDs(fLocale.getName(), fLocale.getName());
+    applyPattern(pattern, success);
+}
+
+MessageFormat::MessageFormat(const UnicodeString& pattern,
+                             const Locale& newLocale,
+                             UErrorCode& success)
+: fLocale(newLocale),
+  msgPattern(success),
+  formatAliases(nullptr),
+  formatAliasesCapacity(0),
+  argTypes(nullptr),
+  argTypeCount(0),
+  argTypeCapacity(0),
+  hasArgTypeConflicts(false),
+  defaultNumberFormat(nullptr),
+  defaultDateFormat(nullptr),
+  cachedFormatters(nullptr),
+  customFormatArgStarts(nullptr),
+  pluralProvider(*this, UPLURAL_TYPE_CARDINAL),
+  ordinalProvider(*this, UPLURAL_TYPE_ORDINAL)
+{
+    setLocaleIDs(fLocale.getName(), fLocale.getName());
+    applyPattern(pattern, success);
+}
+
+MessageFormat::MessageFormat(const UnicodeString& pattern,
+                             const Locale& newLocale,
+                             UParseError& parseError,
+                             UErrorCode& success)
+: fLocale(newLocale),
+  msgPattern(success),
+  formatAliases(nullptr),
+  formatAliasesCapacity(0),
+  argTypes(nullptr),
+  argTypeCount(0),
+  argTypeCapacity(0),
+  hasArgTypeConflicts(false),
+  defaultNumberFormat(nullptr),
+  defaultDateFormat(nullptr),
+  cachedFormatters(nullptr),
+  customFormatArgStarts(nullptr),
+  pluralProvider(*this, UPLURAL_TYPE_CARDINAL),
+  ordinalProvider(*this, UPLURAL_TYPE_ORDINAL)
+{
+    setLocaleIDs(fLocale.getName(), fLocale.getName());
+    applyPattern(pattern, parseError, success);
+}
+
+MessageFormat::MessageFormat(const MessageFormat& that)
+:
+  Format(that),
+  fLocale(that.fLocale),
+  msgPattern(that.msgPattern),
+  formatAliases(nullptr),
+  formatAliasesCapacity(0),
+  argTypes(nullptr),
+  argTypeCount(0),
+  argTypeCapacity(0),
+  hasArgTypeConflicts(that.hasArgTypeConflicts),
+  defaultNumberFormat(nullptr),
+  defaultDateFormat(nullptr),
+  cachedFormatters(nullptr),
+  customFormatArgStarts(nullptr),
+  pluralProvider(*this, UPLURAL_TYPE_CARDINAL),
+  ordinalProvider(*this, UPLURAL_TYPE_ORDINAL)
+{
+    // This will take care of creating the hash tables (since they are nullptr).
+    UErrorCode ec = U_ZERO_ERROR;
+    copyObjects(that, ec);
+    if (U_FAILURE(ec)) {
+        resetPattern();
+    }
+}
+
+MessageFormat::~MessageFormat()
+{
+    uhash_close(cachedFormatters);
+    uhash_close(customFormatArgStarts);
+
+    uprv_free(argTypes);
+    uprv_free(formatAliases);
+    delete defaultNumberFormat;
+    delete defaultDateFormat;
+}
+
+//--------------------------------------------------------------------
+// Variable-size array management
+
+/**
+ * Allocate argTypes[] to at least the given capacity and return
+ * true if successful.  If not, leave argTypes[] unchanged.
+ *
+ * If argTypes is nullptr, allocate it.  If it is not nullptr, enlarge it
+ * if necessary to be at least as large as specified.
+ */
+UBool MessageFormat::allocateArgTypes(int32_t capacity, UErrorCode& status) {
+    if (U_FAILURE(status)) {
+        return false;
+    }
+    if (argTypeCapacity >= capacity) {
+        return true;
+    }
+    if (capacity < DEFAULT_INITIAL_CAPACITY) {
+        capacity = DEFAULT_INITIAL_CAPACITY;
+    } else if (capacity < 2*argTypeCapacity) {
+        capacity = 2*argTypeCapacity;
+    }
+    Formattable::Type* a = (Formattable::Type*)
+            uprv_realloc(argTypes, sizeof(*argTypes) * capacity);
+    if (a == nullptr) {
+        status = U_MEMORY_ALLOCATION_ERROR;
+        return false;
+    }
+    argTypes = a;
+    argTypeCapacity = capacity;
+    return true;
+}
+
+// -------------------------------------
+// assignment operator
+
+const MessageFormat&
+MessageFormat::operator=(const MessageFormat& that)
+{
+    if (this != &that) {
+        // Calls the super class for assignment first.
+        Format::operator=(that);
+
+        setLocale(that.fLocale);
+        msgPattern = that.msgPattern;
+        hasArgTypeConflicts = that.hasArgTypeConflicts;
+
+        UErrorCode ec = U_ZERO_ERROR;
+        copyObjects(that, ec);
+        if (U_FAILURE(ec)) {
+            resetPattern();
+        }
+    }
+    return *this;
+}
+
+bool
+MessageFormat::operator==(const Format& rhs) const
+{
+    if (this == &rhs) return true;
+
+    // Check class ID before checking MessageFormat members
+    if (!Format::operator==(rhs)) return false;
+
+    const MessageFormat& that = static_cast<const MessageFormat&>(rhs);
+    if (msgPattern != that.msgPattern ||
+        fLocale != that.fLocale) {
+        return false;
+    }
+
+    // Compare hashtables.
+    if ((customFormatArgStarts == nullptr) != (that.customFormatArgStarts == nullptr)) {
+        return false;
+    }
+    if (customFormatArgStarts == nullptr) {
+        return true;
+    }
+
+    UErrorCode ec = U_ZERO_ERROR;
+    const int32_t count = uhash_count(customFormatArgStarts);
+    const int32_t rhs_count = uhash_count(that.customFormatArgStarts);
+    if (count != rhs_count) {
+        return false;
+    }
+    int32_t idx = 0, rhs_idx = 0, pos = UHASH_FIRST, rhs_pos = UHASH_FIRST;
+    for (; idx < count && rhs_idx < rhs_count && U_SUCCESS(ec); ++idx, ++rhs_idx) {
+        const UHashElement* cur = uhash_nextElement(customFormatArgStarts, &pos);
+        const UHashElement* rhs_cur = uhash_nextElement(that.customFormatArgStarts, &rhs_pos);
+        if (cur->key.integer != rhs_cur->key.integer) {
+            return false;
+        }
+        const Format* format = (const Format*)uhash_iget(cachedFormatters, cur->key.integer);
+        const Format* rhs_format = (const Format*)uhash_iget(that.cachedFormatters, rhs_cur->key.integer);
+        if (*format != *rhs_format) {
+            return false;
+        }
+    }
+    return true;
+}
+
+// -------------------------------------
+// Creates a copy of this MessageFormat, the caller owns the copy.
+
+MessageFormat*
+MessageFormat::clone() const
+{
+    return new MessageFormat(*this);
+}
+
+// -------------------------------------
+// Sets the locale of this MessageFormat object to theLocale.
+
+void
+MessageFormat::setLocale(const Locale& theLocale)
+{
+    if (fLocale != theLocale) {
+        delete defaultNumberFormat;
+        defaultNumberFormat = nullptr;
+        delete defaultDateFormat;
+        defaultDateFormat = nullptr;
+        fLocale = theLocale;
+        setLocaleIDs(fLocale.getName(), fLocale.getName());
+        pluralProvider.reset();
+        ordinalProvider.reset();
+    }
+}
+
+// -------------------------------------
+// Gets the locale of this MessageFormat object.
+
+const Locale&
+MessageFormat::getLocale() const
+{
+    return fLocale;
+}
+
+void
+MessageFormat::applyPattern(const UnicodeString& newPattern,
+                            UErrorCode& status)
+{
+    UParseError parseError;
+    applyPattern(newPattern,parseError,status);
+}
+
+
+// -------------------------------------
+// Applies the new pattern and returns an error if the pattern
+// is not correct.
+void
+MessageFormat::applyPattern(const UnicodeString& pattern,
+                            UParseError& parseError,
+                            UErrorCode& ec)
+{
+    if(U_FAILURE(ec)) {
+        return;
+    }
+    msgPattern.parse(pattern, &parseError, ec);
+    cacheExplicitFormats(ec);
+
+    if (U_FAILURE(ec)) {
+        resetPattern();
+    }
+}
+
+void MessageFormat::resetPattern() {
+    msgPattern.clear();
+    uhash_close(cachedFormatters);
+    cachedFormatters = nullptr;
+    uhash_close(customFormatArgStarts);
+    customFormatArgStarts = nullptr;
+    argTypeCount = 0;
+    hasArgTypeConflicts = false;
+}
+
+void
+MessageFormat::applyPattern(const UnicodeString& pattern,
+                            UMessagePatternApostropheMode aposMode,
+                            UParseError* parseError,
+                            UErrorCode& status) {
+    if (aposMode != msgPattern.getApostropheMode()) {
+        msgPattern.clearPatternAndSetApostropheMode(aposMode);
+    }
+    UParseError tempParseError;
+    applyPattern(pattern, (parseError == nullptr) ? tempParseError : *parseError, status);
+}
+
+// -------------------------------------
+// Converts this MessageFormat instance to a pattern.
+
+UnicodeString&
+MessageFormat::toPattern(UnicodeString& appendTo) const {
+    if ((customFormatArgStarts != nullptr && 0 != uhash_count(customFormatArgStarts)) ||
+        0 == msgPattern.countParts()
+    ) {
+        appendTo.setToBogus();
+        return appendTo;
+    }
+    return appendTo.append(msgPattern.getPatternString());
+}
+
+int32_t MessageFormat::nextTopLevelArgStart(int32_t partIndex) const {
+    if (partIndex != 0) {
+        partIndex = msgPattern.getLimitPartIndex(partIndex);
+    }
+    for (;;) {
+        UMessagePatternPartType type = msgPattern.getPartType(++partIndex);
+        if (type == UMSGPAT_PART_TYPE_ARG_START) {
+            return partIndex;
+        }
+        if (type == UMSGPAT_PART_TYPE_MSG_LIMIT) {
+            return -1;
+        }
+    }
+}
+
+void MessageFormat::setArgStartFormat(int32_t argStart,
+                                      Format* formatter,
+                                      UErrorCode& status) {
+    if (U_FAILURE(status)) {
+        delete formatter;
+        return;
+    }
+    if (cachedFormatters == nullptr) {
+        cachedFormatters=uhash_open(uhash_hashLong, uhash_compareLong,
+                                    equalFormatsForHash, &status);
+        if (U_FAILURE(status)) {
+            delete formatter;
+            return;
+        }
+        uhash_setValueDeleter(cachedFormatters, uprv_deleteUObject);
+    }
+    if (formatter == nullptr) {
+        formatter = new DummyFormat();
+    }
+    uhash_iput(cachedFormatters, argStart, formatter, &status);
+}
+
+
+UBool MessageFormat::argNameMatches(int32_t partIndex, const UnicodeString& argName, int32_t argNumber) {
+    const MessagePattern::Part& part = msgPattern.getPart(partIndex);
+    return part.getType() == UMSGPAT_PART_TYPE_ARG_NAME ?
+        msgPattern.partSubstringMatches(part, argName) :
+        part.getValue() == argNumber;  // ARG_NUMBER
+}
+
+// Sets a custom formatter for a MessagePattern ARG_START part index.
+// "Custom" formatters are provided by the user via setFormat() or similar APIs.
+void MessageFormat::setCustomArgStartFormat(int32_t argStart,
+                                            Format* formatter,
+                                            UErrorCode& status) {
+    setArgStartFormat(argStart, formatter, status);
+    if (customFormatArgStarts == nullptr) {
+        customFormatArgStarts=uhash_open(uhash_hashLong, uhash_compareLong,
+                                         nullptr, &status);
+    }
+    uhash_iputi(customFormatArgStarts, argStart, 1, &status);
+}
+
+Format* MessageFormat::getCachedFormatter(int32_t argumentNumber) const {
+    if (cachedFormatters == nullptr) {
+        return nullptr;
+    }
+    void* ptr = uhash_iget(cachedFormatters, argumentNumber);
+    if (ptr != nullptr && dynamic_cast<DummyFormat*>((Format*)ptr) == nullptr) {
+        return (Format*) ptr;
+    } else {
+        // Not cached, or a DummyFormat representing setFormat(nullptr).
+        return nullptr;
+    }
+}
+
+// -------------------------------------
+// Adopts the new formats array and updates the array count.
+// This MessageFormat instance owns the new formats.
+void
+MessageFormat::adoptFormats(Format** newFormats,
+                            int32_t count) {
+    if (newFormats == nullptr || count < 0) {
+        return;
+    }
+    // Throw away any cached formatters.
+    if (cachedFormatters != nullptr) {
+        uhash_removeAll(cachedFormatters);
+    }
+    if (customFormatArgStarts != nullptr) {
+        uhash_removeAll(customFormatArgStarts);
+    }
+
+    int32_t formatNumber = 0;
+    UErrorCode status = U_ZERO_ERROR;
+    for (int32_t partIndex = 0;
+        formatNumber < count && U_SUCCESS(status) &&
+            (partIndex = nextTopLevelArgStart(partIndex)) >= 0;) {
+        setCustomArgStartFormat(partIndex, newFormats[formatNumber], status);
+        ++formatNumber;
+    }
+    // Delete those that didn't get used (if any).
+    for (; formatNumber < count; ++formatNumber) {
+        delete newFormats[formatNumber];
+    }
+
+}
+
+// -------------------------------------
+// Sets the new formats array and updates the array count.
+// This MessageFormat instance makes a copy of the new formats.
+
+void
+MessageFormat::setFormats(const Format** newFormats,
+                          int32_t count) {
+    if (newFormats == nullptr || count < 0) {
+        return;
+    }
+    // Throw away any cached formatters.
+    if (cachedFormatters != nullptr) {
+        uhash_removeAll(cachedFormatters);
+    }
+    if (customFormatArgStarts != nullptr) {
+        uhash_removeAll(customFormatArgStarts);
+    }
+
+    UErrorCode status = U_ZERO_ERROR;
+    int32_t formatNumber = 0;
+    for (int32_t partIndex = 0;
+        formatNumber < count && U_SUCCESS(status) && (partIndex = nextTopLevelArgStart(partIndex)) >= 0;) {
+      Format* newFormat = nullptr;
+      if (newFormats[formatNumber] != nullptr) {
+          newFormat = newFormats[formatNumber]->clone();
+          if (newFormat == nullptr) {
+              status = U_MEMORY_ALLOCATION_ERROR;
+          }
+      }
+      setCustomArgStartFormat(partIndex, newFormat, status);
+      ++formatNumber;
+    }
+    if (U_FAILURE(status)) {
+        resetPattern();
+    }
+}
+
+// -------------------------------------
+// Adopt a single format by format number.
+// Do nothing if the format number is not less than the array count.
+
+void
+MessageFormat::adoptFormat(int32_t n, Format *newFormat) {
+    LocalPointer<Format> p(newFormat);
+    if (n >= 0) {
+        int32_t formatNumber = 0;
+        for (int32_t partIndex = 0; (partIndex = nextTopLevelArgStart(partIndex)) >= 0;) {
+            if (n == formatNumber) {
+                UErrorCode status = U_ZERO_ERROR;
+                setCustomArgStartFormat(partIndex, p.orphan(), status);
+                return;
+            }
+            ++formatNumber;
+        }
+    }
+}
+
+// -------------------------------------
+// Adopt a single format by format name.
+// Do nothing if there is no match of formatName.
+void
+MessageFormat::adoptFormat(const UnicodeString& formatName,
+                           Format* formatToAdopt,
+                           UErrorCode& status) {
+    LocalPointer<Format> p(formatToAdopt);
+    if (U_FAILURE(status)) {
+        return;
+    }
+    int32_t argNumber = MessagePattern::validateArgumentName(formatName);
+    if (argNumber < UMSGPAT_ARG_NAME_NOT_NUMBER) {
+        status = U_ILLEGAL_ARGUMENT_ERROR;
+        return;
+    }
+    for (int32_t partIndex = 0;
+        (partIndex = nextTopLevelArgStart(partIndex)) >= 0 && U_SUCCESS(status);
+    ) {
+        if (argNameMatches(partIndex + 1, formatName, argNumber)) {
+            Format* f;
+            if (p.isValid()) {
+                f = p.orphan();
+            } else if (formatToAdopt == nullptr) {
+                f = nullptr;
+            } else {
+                f = formatToAdopt->clone();
+                if (f == nullptr) {
+                    status = U_MEMORY_ALLOCATION_ERROR;
+                    return;
+                }
+            }
+            setCustomArgStartFormat(partIndex, f, status);
+        }
+    }
+}
+
+// -------------------------------------
+// Set a single format.
+// Do nothing if the variable is not less than the array count.
+void
+MessageFormat::setFormat(int32_t n, const Format& newFormat) {
+
+    if (n >= 0) {
+        int32_t formatNumber = 0;
+        for (int32_t partIndex = 0;
+             (partIndex = nextTopLevelArgStart(partIndex)) >= 0;) {
+            if (n == formatNumber) {
+                Format* new_format = newFormat.clone();
+                if (new_format) {
+                    UErrorCode status = U_ZERO_ERROR;
+                    setCustomArgStartFormat(partIndex, new_format, status);
+                }
+                return;
+            }
+            ++formatNumber;
+        }
+    }
+}
+
+// -------------------------------------
+// Get a single format by format name.
+// Do nothing if the variable is not less than the array count.
+Format *
+MessageFormat::getFormat(const UnicodeString& formatName, UErrorCode& status) {
+    if (U_FAILURE(status) || cachedFormatters == nullptr) return nullptr;
+
+    int32_t argNumber = MessagePattern::validateArgumentName(formatName);
+    if (argNumber < UMSGPAT_ARG_NAME_NOT_NUMBER) {
+        status = U_ILLEGAL_ARGUMENT_ERROR;
+        return nullptr;
+    }
+    for (int32_t partIndex = 0; (partIndex = nextTopLevelArgStart(partIndex)) >= 0;) {
+        if (argNameMatches(partIndex + 1, formatName, argNumber)) {
+            return getCachedFormatter(partIndex);
+        }
+    }
+    return nullptr;
+}
+
+// -------------------------------------
+// Set a single format by format name
+// Do nothing if the variable is not less than the array count.
+void
+MessageFormat::setFormat(const UnicodeString& formatName,
+                         const Format& newFormat,
+                         UErrorCode& status) {
+    if (U_FAILURE(status)) return;
+
+    int32_t argNumber = MessagePattern::validateArgumentName(formatName);
+    if (argNumber < UMSGPAT_ARG_NAME_NOT_NUMBER) {
+        status = U_ILLEGAL_ARGUMENT_ERROR;
+        return;
+    }
+    for (int32_t partIndex = 0;
+        (partIndex = nextTopLevelArgStart(partIndex)) >= 0 && U_SUCCESS(status);
+    ) {
+        if (argNameMatches(partIndex + 1, formatName, argNumber)) {
+            Format* new_format = newFormat.clone();
+            if (new_format == nullptr) {
+                status = U_MEMORY_ALLOCATION_ERROR;
+                return;
+            }
+            setCustomArgStartFormat(partIndex, new_format, status);
+        }
+    }
+}
+
+// -------------------------------------
+// Gets the format array.
+const Format**
+MessageFormat::getFormats(int32_t& cnt) const
+{
+    // This old API returns an array (which we hold) of Format*
+    // pointers.  The array is valid up to the next call to any
+    // method on this object.  We construct and resize an array
+    // on demand that contains aliases to the subformats[i].format
+    // pointers.
+
+    // Get total required capacity first (it's refreshed on each call).
+    int32_t totalCapacity = 0;
+    for (int32_t partIndex = 0; (partIndex = nextTopLevelArgStart(partIndex)) >= 0; ++totalCapacity) {}
+
+    MessageFormat* t = const_cast<MessageFormat*> (this);
+    cnt = 0;
+    if (formatAliases == nullptr) {
+        t->formatAliasesCapacity = totalCapacity;
+        Format** a = (Format**)
+            uprv_malloc(sizeof(Format*) * formatAliasesCapacity);
+        if (a == nullptr) {
+            t->formatAliasesCapacity = 0;
+            return nullptr;
+        }
+        t->formatAliases = a;
+    } else if (totalCapacity > formatAliasesCapacity) {
+        Format** a = (Format**)
+            uprv_realloc(formatAliases, sizeof(Format*) * totalCapacity);
+        if (a == nullptr) {
+            t->formatAliasesCapacity = 0;
+            return nullptr;
+        }
+        t->formatAliases = a;
+        t->formatAliasesCapacity = totalCapacity;
+    }
+
+    for (int32_t partIndex = 0; (partIndex = nextTopLevelArgStart(partIndex)) >= 0;) {
+        t->formatAliases[cnt++] = getCachedFormatter(partIndex);
+    }
+
+    return (const Format**)formatAliases;
+}
+
+
+UnicodeString MessageFormat::getArgName(int32_t partIndex) {
+    const MessagePattern::Part& part = msgPattern.getPart(partIndex);
+    return msgPattern.getSubstring(part);
+}
+
+StringEnumeration*
+MessageFormat::getFormatNames(UErrorCode& status) {
+    if (U_FAILURE(status))  return nullptr;
+
+    LocalPointer<UVector> formatNames(new UVector(status), status);
+    if (U_FAILURE(status)) {
+        return nullptr;
+    }
+    formatNames->setDeleter(uprv_deleteUObject);
+
+    for (int32_t partIndex = 0; (partIndex = nextTopLevelArgStart(partIndex)) >= 0;) {
+        LocalPointer<UnicodeString> name(getArgName(partIndex + 1).clone(), status);
+        formatNames->adoptElement(name.orphan(), status);
+        if (U_FAILURE(status))  return nullptr;
+    }
+
+    LocalPointer<StringEnumeration> nameEnumerator(
+        new FormatNameEnumeration(std::move(formatNames), status), status);
+    return U_SUCCESS(status) ? nameEnumerator.orphan() : nullptr;
+}
+
+// -------------------------------------
+// Formats the source Formattable array and copy into the result buffer.
+// Ignore the FieldPosition result for error checking.
+
+UnicodeString&
+MessageFormat::format(const Formattable* source,
+                      int32_t cnt,
+                      UnicodeString& appendTo,
+                      FieldPosition& ignore,
+                      UErrorCode& success) const
+{
+    return format(source, nullptr, cnt, appendTo, &ignore, success);
+}
+
+// -------------------------------------
+// Internally creates a MessageFormat instance based on the
+// pattern and formats the arguments Formattable array and
+// copy into the appendTo buffer.
+
+UnicodeString&
+MessageFormat::format(  const UnicodeString& pattern,
+                        const Formattable* arguments,
+                        int32_t cnt,
+                        UnicodeString& appendTo,
+                        UErrorCode& success)
+{
+    MessageFormat temp(pattern, success);
+    return temp.format(arguments, nullptr, cnt, appendTo, nullptr, success);
+}
+
+// -------------------------------------
+// Formats the source Formattable object and copy into the
+// appendTo buffer.  The Formattable object must be an array
+// of Formattable instances, returns error otherwise.
+
+UnicodeString&
+MessageFormat::format(const Formattable& source,
+                      UnicodeString& appendTo,
+                      FieldPosition& ignore,
+                      UErrorCode& success) const
+{
+    if (U_FAILURE(success))
+        return appendTo;
+    if (source.getType() != Formattable::kArray) {
+        success = U_ILLEGAL_ARGUMENT_ERROR;
+        return appendTo;
+    }
+    int32_t cnt;
+    const Formattable* tmpPtr = source.getArray(cnt);
+    return format(tmpPtr, nullptr, cnt, appendTo, &ignore, success);
+}
+
+UnicodeString&
+MessageFormat::format(const UnicodeString* argumentNames,
+                      const Formattable* arguments,
+                      int32_t count,
+                      UnicodeString& appendTo,
+                      UErrorCode& success) const {
+    return format(arguments, argumentNames, count, appendTo, nullptr, success);
+}
+
+// Does linear search to find the match for an ArgName.
+const Formattable* MessageFormat::getArgFromListByName(const Formattable* arguments,
+                                                       const UnicodeString *argumentNames,
+                                                       int32_t cnt, UnicodeString& name) const {
+    for (int32_t i = 0; i < cnt; ++i) {
+        if (0 == argumentNames[i].compare(name)) {
+            return arguments + i;
+        }
+    }
+    return nullptr;
+}
+
+
+UnicodeString&
+MessageFormat::format(const Formattable* arguments,
+                      const UnicodeString *argumentNames,
+                      int32_t cnt,
+                      UnicodeString& appendTo,
+                      FieldPosition* pos,
+                      UErrorCode& status) const {
+    if (U_FAILURE(status)) {
+        return appendTo;
+    }
+
+    UnicodeStringAppendable usapp(appendTo);
+    AppendableWrapper app(usapp);
+    format(0, nullptr, arguments, argumentNames, cnt, app, pos, status);
+    return appendTo;
+}
+
+namespace {
+
+/**
+ * Mutable input/output values for the PluralSelectorProvider.
+ * Separate so that it is possible to make MessageFormat Freezable.
+ */
+class PluralSelectorContext {
+public:
+    PluralSelectorContext(int32_t start, const UnicodeString &name,
+                          const Formattable &num, double off, UErrorCode &errorCode)
+            : startIndex(start), argName(name), offset(off),
+              numberArgIndex(-1), formatter(nullptr), forReplaceNumber(false) {
+        // number needs to be set even when select() is not called.
+        // Keep it as a Number/Formattable:
+        // For format() methods, and to preserve information (e.g., BigDecimal).
+        if(off == 0) {
+            number = num;
+        } else {
+            number = num.getDouble(errorCode) - off;
+        }
+    }
+
+    // Input values for plural selection with decimals.
+    int32_t startIndex;
+    const UnicodeString &argName;
+    /** argument number - plural offset */
+    Formattable number;
+    double offset;
+    // Output values for plural selection with decimals.
+    /** -1 if REPLACE_NUMBER, 0 arg not found, >0 ARG_START index */
+    int32_t numberArgIndex;
+    const Format *formatter;
+    /** formatted argument number - plural offset */
+    UnicodeString numberString;
+    /** true if number-offset was formatted with the stock number formatter */
+    UBool forReplaceNumber;
+};
+
+}  // namespace
+
+// if argumentNames is nullptr, this means arguments is a numeric array.
+// arguments can not be nullptr.
+// We use const void *plNumber rather than const PluralSelectorContext *pluralNumber
+// so that we need not declare the PluralSelectorContext in the public header file.
+void MessageFormat::format(int32_t msgStart, const void *plNumber,
+                           const Formattable* arguments,
+                           const UnicodeString *argumentNames,
+                           int32_t cnt,
+                           AppendableWrapper& appendTo,
+                           FieldPosition* ignore,
+                           UErrorCode& success) const {
+    if (U_FAILURE(success)) {
+        return;
+    }
+
+    const UnicodeString& msgString = msgPattern.getPatternString();
+    int32_t prevIndex = msgPattern.getPart(msgStart).getLimit();
+    for (int32_t i = msgStart + 1; U_SUCCESS(success) ; ++i) {
+        const MessagePattern::Part* part = &msgPattern.getPart(i);
+        const UMessagePatternPartType type = part->getType();
+        int32_t index = part->getIndex();
+        appendTo.append(msgString, prevIndex, index - prevIndex);
+        if (type == UMSGPAT_PART_TYPE_MSG_LIMIT) {
+            return;
+        }
+        prevIndex = part->getLimit();
+        if (type == UMSGPAT_PART_TYPE_REPLACE_NUMBER) {
+            const PluralSelectorContext &pluralNumber =
+                *static_cast<const PluralSelectorContext *>(plNumber);
+            if(pluralNumber.forReplaceNumber) {
+                // number-offset was already formatted.
+                appendTo.formatAndAppend(pluralNumber.formatter,
+                        pluralNumber.number, pluralNumber.numberString, success);
+            } else {
+                const NumberFormat* nf = getDefaultNumberFormat(success);
+                appendTo.formatAndAppend(nf, pluralNumber.number, success);
+            }
+            continue;
+        }
+        if (type != UMSGPAT_PART_TYPE_ARG_START) {
+            continue;
+        }
+        int32_t argLimit = msgPattern.getLimitPartIndex(i);
+        UMessagePatternArgType argType = part->getArgType();
+        part = &msgPattern.getPart(++i);
+        const Formattable* arg;
+        UBool noArg = false;
+        UnicodeString argName = msgPattern.getSubstring(*part);
+        if (argumentNames == nullptr) {
+            int32_t argNumber = part->getValue();  // ARG_NUMBER
+            if (0 <= argNumber && argNumber < cnt) {
+                arg = arguments + argNumber;
+            } else {
+                arg = nullptr;
+                noArg = true;
+            }
+        } else {
+            arg = getArgFromListByName(arguments, argumentNames, cnt, argName);
+            if (arg == nullptr) {
+                noArg = true;
+            }
+        }
+        ++i;
+        int32_t prevDestLength = appendTo.length();
+        const Format* formatter = nullptr;
+        if (noArg) {
+            appendTo.append(
+                UnicodeString(LEFT_CURLY_BRACE).append(argName).append(RIGHT_CURLY_BRACE));
+        } else if (arg == nullptr) {
+            appendTo.append(NULL_STRING, 4);
+        } else if(plNumber!=nullptr &&
+                static_cast<const PluralSelectorContext *>(plNumber)->numberArgIndex==(i-2)) {
+            const PluralSelectorContext &pluralNumber =
+                *static_cast<const PluralSelectorContext *>(plNumber);
+            if(pluralNumber.offset == 0) {
+                // The number was already formatted with this formatter.
+                appendTo.formatAndAppend(pluralNumber.formatter, pluralNumber.number,
+                                         pluralNumber.numberString, success);
+            } else {
+                // Do not use the formatted (number-offset) string for a named argument
+                // that formats the number without subtracting the offset.
+                appendTo.formatAndAppend(pluralNumber.formatter, *arg, success);
+            }
+        } else if ((formatter = getCachedFormatter(i -2)) != 0) {
+            // Handles all ArgType.SIMPLE, and formatters from setFormat() and its siblings.
+            if (dynamic_cast<const ChoiceFormat*>(formatter) ||
+                dynamic_cast<const PluralFormat*>(formatter) ||
+                dynamic_cast<const SelectFormat*>(formatter)) {
+                // We only handle nested formats here if they were provided via
+                // setFormat() or its siblings. Otherwise they are not cached and instead
+                // handled below according to argType.
+                UnicodeString subMsgString;
+                formatter->format(*arg, subMsgString, success);
+                if (subMsgString.indexOf(LEFT_CURLY_BRACE) >= 0 ||
+                    (subMsgString.indexOf(SINGLE_QUOTE) >= 0 && !MessageImpl::jdkAposMode(msgPattern))
+                ) {
+                    MessageFormat subMsgFormat(subMsgString, fLocale, success);
+                    subMsgFormat.format(0, nullptr, arguments, argumentNames, cnt, appendTo, ignore, success);
+                } else {
+                    appendTo.append(subMsgString);
+                }
+            } else {
+                appendTo.formatAndAppend(formatter, *arg, success);
+            }
+        } else if (argType == UMSGPAT_ARG_TYPE_NONE || (cachedFormatters && uhash_iget(cachedFormatters, i - 2))) {
+            // We arrive here if getCachedFormatter returned nullptr, but there was actually an element in the hash table.
+            // This can only happen if the hash table contained a DummyFormat, so the if statement above is a check
+            // for the hash table containing DummyFormat.
+            if (arg->isNumeric()) {
+                const NumberFormat* nf = getDefaultNumberFormat(success);
+                appendTo.formatAndAppend(nf, *arg, success);
+            } else if (arg->getType() == Formattable::kDate) {
+                const DateFormat* df = getDefaultDateFormat(success);
+                appendTo.formatAndAppend(df, *arg, success);
+            } else {
+                appendTo.append(arg->getString(success));
+            }
+        } else if (argType == UMSGPAT_ARG_TYPE_CHOICE) {
+            if (!arg->isNumeric()) {
+                success = U_ILLEGAL_ARGUMENT_ERROR;
+                return;
+            }
+            // We must use the Formattable::getDouble() variant with the UErrorCode parameter
+            // because only this one converts non-double numeric types to double.
+            const double number = arg->getDouble(success);
+            int32_t subMsgStart = ChoiceFormat::findSubMessage(msgPattern, i, number);
+            formatComplexSubMessage(subMsgStart, nullptr, arguments, argumentNames,
+                                    cnt, appendTo, success);
+        } else if (UMSGPAT_ARG_TYPE_HAS_PLURAL_STYLE(argType)) {
+            if (!arg->isNumeric()) {
+                success = U_ILLEGAL_ARGUMENT_ERROR;
+                return;
+            }
+            const PluralSelectorProvider &selector =
+                argType == UMSGPAT_ARG_TYPE_PLURAL ? pluralProvider : ordinalProvider;
+            // We must use the Formattable::getDouble() variant with the UErrorCode parameter
+            // because only this one converts non-double numeric types to double.
+            double offset = msgPattern.getPluralOffset(i);
+            PluralSelectorContext context(i, argName, *arg, offset, success);
+            int32_t subMsgStart = PluralFormat::findSubMessage(
+                    msgPattern, i, selector, &context, arg->getDouble(success), success);
+            formatComplexSubMessage(subMsgStart, &context, arguments, argumentNames,
+                                    cnt, appendTo, success);
+        } else if (argType == UMSGPAT_ARG_TYPE_SELECT) {
+            int32_t subMsgStart = SelectFormat::findSubMessage(msgPattern, i, arg->getString(success), success);
+            formatComplexSubMessage(subMsgStart, nullptr, arguments, argumentNames,
+                                    cnt, appendTo, success);
+        } else {
+            // This should never happen.
+            success = U_INTERNAL_PROGRAM_ERROR;
+            return;
+        }
+        ignore = updateMetaData(appendTo, prevDestLength, ignore, arg);
+        prevIndex = msgPattern.getPart(argLimit).getLimit();
+        i = argLimit;
+    }
+}
+
+
+void MessageFormat::formatComplexSubMessage(int32_t msgStart,
+                                            const void *plNumber,
+                                            const Formattable* arguments,
+                                            const UnicodeString *argumentNames,
+                                            int32_t cnt,
+                                            AppendableWrapper& appendTo,
+                                            UErrorCode& success) const {
+    if (U_FAILURE(success)) {
+        return;
+    }
+
+    if (!MessageImpl::jdkAposMode(msgPattern)) {
+        format(msgStart, plNumber, arguments, argumentNames, cnt, appendTo, nullptr, success);
+        return;
+    }
+
+    // JDK compatibility mode: (see JDK MessageFormat.format() API docs)
+    // - remove SKIP_SYNTAX; that is, remove half of the apostrophes
+    // - if the result string contains an open curly brace '{' then
+    //   instantiate a temporary MessageFormat object and format again;
+    //   otherwise just append the result string
+    const UnicodeString& msgString = msgPattern.getPatternString();
+    UnicodeString sb;
+    int32_t prevIndex = msgPattern.getPart(msgStart).getLimit();
+    for (int32_t i = msgStart;;) {
+        const MessagePattern::Part& part = msgPattern.getPart(++i);
+        const UMessagePatternPartType type = part.getType();
+        int32_t index = part.getIndex();
+        if (type == UMSGPAT_PART_TYPE_MSG_LIMIT) {
+            sb.append(msgString, prevIndex, index - prevIndex);
+            break;
+        } else if (type == UMSGPAT_PART_TYPE_REPLACE_NUMBER || type == UMSGPAT_PART_TYPE_SKIP_SYNTAX) {
+            sb.append(msgString, prevIndex, index - prevIndex);
+            if (type == UMSGPAT_PART_TYPE_REPLACE_NUMBER) {
+                const PluralSelectorContext &pluralNumber =
+                    *static_cast<const PluralSelectorContext *>(plNumber);
+                if(pluralNumber.forReplaceNumber) {
+                    // number-offset was already formatted.
+                    sb.append(pluralNumber.numberString);
+                } else {
+                    const NumberFormat* nf = getDefaultNumberFormat(success);
+                    sb.append(nf->format(pluralNumber.number, sb, success));
+                }
+            }
+            prevIndex = part.getLimit();
+        } else if (type == UMSGPAT_PART_TYPE_ARG_START) {
+            sb.append(msgString, prevIndex, index - prevIndex);
+            prevIndex = index;
+            i = msgPattern.getLimitPartIndex(i);
+            index = msgPattern.getPart(i).getLimit();
+            MessageImpl::appendReducedApostrophes(msgString, prevIndex, index, sb);
+            prevIndex = index;
+        }
+    }
+    if (sb.indexOf(LEFT_CURLY_BRACE) >= 0) {
+        UnicodeString emptyPattern;  // gcc 3.3.3 fails with "UnicodeString()" as the first parameter.
+        MessageFormat subMsgFormat(emptyPattern, fLocale, success);
+        subMsgFormat.applyPattern(sb, UMSGPAT_APOS_DOUBLE_REQUIRED, nullptr, success);
+        subMsgFormat.format(0, nullptr, arguments, argumentNames, cnt, appendTo, nullptr, success);
+    } else {
+        appendTo.append(sb);
+    }
+}
+
+
+UnicodeString MessageFormat::getLiteralStringUntilNextArgument(int32_t from) const {
+    const UnicodeString& msgString=msgPattern.getPatternString();
+    int32_t prevIndex=msgPattern.getPart(from).getLimit();
+    UnicodeString b;
+    for (int32_t i = from + 1; ; ++i) {
+        const MessagePattern::Part& part = msgPattern.getPart(i);
+        const UMessagePatternPartType type=part.getType();
+        int32_t index=part.getIndex();
+        b.append(msgString, prevIndex, index - prevIndex);
+        if(type==UMSGPAT_PART_TYPE_ARG_START || type==UMSGPAT_PART_TYPE_MSG_LIMIT) {
+            return b;
+        }
+        // Unexpected Part "part" in parsed message.
+        U_ASSERT(type==UMSGPAT_PART_TYPE_SKIP_SYNTAX || type==UMSGPAT_PART_TYPE_INSERT_CHAR);
+        prevIndex=part.getLimit();
+    }
+}
+
+
+FieldPosition* MessageFormat::updateMetaData(AppendableWrapper& /*dest*/, int32_t /*prevLength*/,
+                             FieldPosition* /*fp*/, const Formattable* /*argId*/) const {
+    // Unlike in Java, there are no field attributes defined for MessageFormat. Do nothing.
+    return nullptr;
+    /*
+      if (fp != nullptr && Field.ARGUMENT.equals(fp.getFieldAttribute())) {
+          fp->setBeginIndex(prevLength);
+          fp->setEndIndex(dest.get_length());
+          return nullptr;
+      }
+      return fp;
+    */
+}
+
+int32_t
+MessageFormat::findOtherSubMessage(int32_t partIndex) const {
+    int32_t count=msgPattern.countParts();
+    const MessagePattern::Part *part = &msgPattern.getPart(partIndex);
+    if(MessagePattern::Part::hasNumericValue(part->getType())) {
+        ++partIndex;
+    }
+    // Iterate over (ARG_SELECTOR [ARG_INT|ARG_DOUBLE] message) tuples
+    // until ARG_LIMIT or end of plural-only pattern.
+    UnicodeString other(false, OTHER_STRING, 5);
+    do {
+        part=&msgPattern.getPart(partIndex++);
+        UMessagePatternPartType type=part->getType();
+        if(type==UMSGPAT_PART_TYPE_ARG_LIMIT) {
+            break;
+        }
+        U_ASSERT(type==UMSGPAT_PART_TYPE_ARG_SELECTOR);
+        // part is an ARG_SELECTOR followed by an optional explicit value, and then a message
+        if(msgPattern.partSubstringMatches(*part, other)) {
+            return partIndex;
+        }
+        if(MessagePattern::Part::hasNumericValue(msgPattern.getPartType(partIndex))) {
+            ++partIndex;  // skip the numeric-value part of "=1" etc.
+        }
+        partIndex=msgPattern.getLimitPartIndex(partIndex);
+    } while(++partIndex<count);
+    return 0;
+}
+
+int32_t
+MessageFormat::findFirstPluralNumberArg(int32_t msgStart, const UnicodeString &argName) const {
+    for(int32_t i=msgStart+1;; ++i) {
+        const MessagePattern::Part &part=msgPattern.getPart(i);
+        UMessagePatternPartType type=part.getType();
+        if(type==UMSGPAT_PART_TYPE_MSG_LIMIT) {
+            return 0;
+        }
+        if(type==UMSGPAT_PART_TYPE_REPLACE_NUMBER) {
+            return -1;
+        }
+        if(type==UMSGPAT_PART_TYPE_ARG_START) {
+            UMessagePatternArgType argType=part.getArgType();
+            if(!argName.isEmpty() && (argType==UMSGPAT_ARG_TYPE_NONE || argType==UMSGPAT_ARG_TYPE_SIMPLE)) {
+                // ARG_NUMBER or ARG_NAME
+                if(msgPattern.partSubstringMatches(msgPattern.getPart(i+1), argName)) {
+                    return i;
+                }
+            }
+            i=msgPattern.getLimitPartIndex(i);
+        }
+    }
+}
+
+void MessageFormat::copyObjects(const MessageFormat& that, UErrorCode& ec) {
+    // Deep copy pointer fields.
+    // We need not copy the formatAliases because they are re-filled
+    // in each getFormats() call.
+    // The defaultNumberFormat, defaultDateFormat and pluralProvider.rules
+    // also get created on demand.
+    argTypeCount = that.argTypeCount;
+    if (argTypeCount > 0) {
+        if (!allocateArgTypes(argTypeCount, ec)) {
+            return;
+        }
+        uprv_memcpy(argTypes, that.argTypes, argTypeCount * sizeof(argTypes[0]));
+    }
+    if (cachedFormatters != nullptr) {
+        uhash_removeAll(cachedFormatters);
+    }
+    if (customFormatArgStarts != nullptr) {
+        uhash_removeAll(customFormatArgStarts);
+    }
+    if (that.cachedFormatters) {
+        if (cachedFormatters == nullptr) {
+            cachedFormatters=uhash_open(uhash_hashLong, uhash_compareLong,
+                                        equalFormatsForHash, &ec);
+            if (U_FAILURE(ec)) {
+                return;
+            }
+            uhash_setValueDeleter(cachedFormatters, uprv_deleteUObject);
+        }
+
+        const int32_t count = uhash_count(that.cachedFormatters);
+        int32_t pos, idx;
+        for (idx = 0, pos = UHASH_FIRST; idx < count && U_SUCCESS(ec); ++idx) {
+            const UHashElement* cur = uhash_nextElement(that.cachedFormatters, &pos);
+            Format* newFormat = ((Format*)(cur->value.pointer))->clone();
+            if (newFormat) {
+                uhash_iput(cachedFormatters, cur->key.integer, newFormat, &ec);
+            } else {
+                ec = U_MEMORY_ALLOCATION_ERROR;
+                return;
+            }
+        }
+    }
+    if (that.customFormatArgStarts) {
+        if (customFormatArgStarts == nullptr) {
+            customFormatArgStarts=uhash_open(uhash_hashLong, uhash_compareLong,
+                                              nullptr, &ec);
+        }
+        const int32_t count = uhash_count(that.customFormatArgStarts);
+        int32_t pos, idx;
+        for (idx = 0, pos = UHASH_FIRST; idx < count && U_SUCCESS(ec); ++idx) {
+            const UHashElement* cur = uhash_nextElement(that.customFormatArgStarts, &pos);
+            uhash_iputi(customFormatArgStarts, cur->key.integer, cur->value.integer, &ec);
+        }
+    }
+}
+
+
+Formattable*
+MessageFormat::parse(int32_t msgStart,
+                     const UnicodeString& source,
+                     ParsePosition& pos,
+                     int32_t& count,
+                     UErrorCode& ec) const {
+    count = 0;
+    if (U_FAILURE(ec)) {
+        pos.setErrorIndex(pos.getIndex());
+        return nullptr;
+    }
+    // parse() does not work with named arguments.
+    if (msgPattern.hasNamedArguments()) {
+        ec = U_ARGUMENT_TYPE_MISMATCH;
+        pos.setErrorIndex(pos.getIndex());
+        return nullptr;
+    }
+    LocalArray<Formattable> resultArray(new Formattable[argTypeCount ? argTypeCount : 1]);
+    const UnicodeString& msgString=msgPattern.getPatternString();
+    int32_t prevIndex=msgPattern.getPart(msgStart).getLimit();
+    int32_t sourceOffset = pos.getIndex();
+    ParsePosition tempStatus(0);
+
+    for(int32_t i=msgStart+1; ; ++i) {
+        UBool haveArgResult = false;
+        const MessagePattern::Part* part=&msgPattern.getPart(i);
+        const UMessagePatternPartType type=part->getType();
+        int32_t index=part->getIndex();
+        // Make sure the literal string matches.
+        int32_t len = index - prevIndex;
+        if (len == 0 || (0 == msgString.compare(prevIndex, len, source, sourceOffset, len))) {
+            sourceOffset += len;
+            prevIndex += len;
+        } else {
+            pos.setErrorIndex(sourceOffset);
+            return nullptr; // leave index as is to signal error
+        }
+        if(type==UMSGPAT_PART_TYPE_MSG_LIMIT) {
+            // Things went well! Done.
+            pos.setIndex(sourceOffset);
+            return resultArray.orphan();
+        }
+        if(type==UMSGPAT_PART_TYPE_SKIP_SYNTAX || type==UMSGPAT_PART_TYPE_INSERT_CHAR) {
+            prevIndex=part->getLimit();
+            continue;
+        }
+        // We do not support parsing Plural formats. (No REPLACE_NUMBER here.)
+        // Unexpected Part "part" in parsed message.
+        U_ASSERT(type==UMSGPAT_PART_TYPE_ARG_START);
+        int32_t argLimit=msgPattern.getLimitPartIndex(i);
+
+        UMessagePatternArgType argType=part->getArgType();
+        part=&msgPattern.getPart(++i);
+        int32_t argNumber = part->getValue();  // ARG_NUMBER
+        UnicodeString key;
+        ++i;
+        const Format* formatter = nullptr;
+        Formattable& argResult = resultArray[argNumber];
+
+        if(cachedFormatters!=nullptr && (formatter = getCachedFormatter(i - 2))!=nullptr) {
+            // Just parse using the formatter.
+            tempStatus.setIndex(sourceOffset);
+            formatter->parseObject(source, argResult, tempStatus);
+            if (tempStatus.getIndex() == sourceOffset) {
+                pos.setErrorIndex(sourceOffset);
+                return nullptr; // leave index as is to signal error
+            }
+            sourceOffset = tempStatus.getIndex();
+            haveArgResult = true;
+        } else if(
+            argType==UMSGPAT_ARG_TYPE_NONE || (cachedFormatters && uhash_iget(cachedFormatters, i -2))) {
+            // We arrive here if getCachedFormatter returned nullptr, but there was actually an element in the hash table.
+            // This can only happen if the hash table contained a DummyFormat, so the if statement above is a check
+            // for the hash table containing DummyFormat.
+
+            // Match as a string.
+            // if at end, use longest possible match
+            // otherwise uses first match to intervening string
+            // does NOT recursively try all possibilities
+            UnicodeString stringAfterArgument = getLiteralStringUntilNextArgument(argLimit);
+            int32_t next;
+            if (!stringAfterArgument.isEmpty()) {
+                next = source.indexOf(stringAfterArgument, sourceOffset);
+            } else {
+                next = source.length();
+            }
+            if (next < 0) {
+                pos.setErrorIndex(sourceOffset);
+                return nullptr; // leave index as is to signal error
+            } else {
+                UnicodeString strValue(source.tempSubString(sourceOffset, next - sourceOffset));
+                UnicodeString compValue;
+                compValue.append(LEFT_CURLY_BRACE);
+                itos(argNumber, compValue);
+                compValue.append(RIGHT_CURLY_BRACE);
+                if (0 != strValue.compare(compValue)) {
+                    argResult.setString(strValue);
+                    haveArgResult = true;
+                }
+                sourceOffset = next;
+            }
+        } else if(argType==UMSGPAT_ARG_TYPE_CHOICE) {
+            tempStatus.setIndex(sourceOffset);
+            double choiceResult = ChoiceFormat::parseArgument(msgPattern, i, source, tempStatus);
+            if (tempStatus.getIndex() == sourceOffset) {
+                pos.setErrorIndex(sourceOffset);
+                return nullptr; // leave index as is to signal error
+            }
+            argResult.setDouble(choiceResult);
+            haveArgResult = true;
+            sourceOffset = tempStatus.getIndex();
+        } else if(UMSGPAT_ARG_TYPE_HAS_PLURAL_STYLE(argType) || argType==UMSGPAT_ARG_TYPE_SELECT) {
+            // Parsing not supported.
+            ec = U_UNSUPPORTED_ERROR;
+            return nullptr;
+        } else {
+            // This should never happen.
+            ec = U_INTERNAL_PROGRAM_ERROR;
+            return nullptr;
+        }
+        if (haveArgResult && count <= argNumber) {
+            count = argNumber + 1;
+        }
+        prevIndex=msgPattern.getPart(argLimit).getLimit();
+        i=argLimit;
+    }
+}
+// -------------------------------------
+// Parses the source pattern and returns the Formattable objects array,
+// the array count and the ending parse position.  The caller of this method
+// owns the array.
+
+Formattable*
+MessageFormat::parse(const UnicodeString& source,
+                     ParsePosition& pos,
+                     int32_t& count) const {
+    UErrorCode ec = U_ZERO_ERROR;
+    return parse(0, source, pos, count, ec);
+}
+
+// -------------------------------------
+// Parses the source string and returns the array of
+// Formattable objects and the array count.  The caller
+// owns the returned array.
+
+Formattable*
+MessageFormat::parse(const UnicodeString& source,
+                     int32_t& cnt,
+                     UErrorCode& success) const
+{
+    if (msgPattern.hasNamedArguments()) {
+        success = U_ARGUMENT_TYPE_MISMATCH;
+        return nullptr;
+    }
+    ParsePosition status(0);
+    // Calls the actual implementation method and starts
+    // from zero offset of the source text.
+    Formattable* result = parse(source, status, cnt);
+    if (status.getIndex() == 0) {
+        success = U_MESSAGE_PARSE_ERROR;
+        delete[] result;
+        return nullptr;
+    }
+    return result;
+}
+
+// -------------------------------------
+// Parses the source text and copy into the result buffer.
+
+void
+MessageFormat::parseObject( const UnicodeString& source,
+                            Formattable& result,
+                            ParsePosition& status) const
+{
+    int32_t cnt = 0;
+    Formattable* tmpResult = parse(source, status, cnt);
+    if (tmpResult != nullptr)
+        result.adoptArray(tmpResult, cnt);
+}
+
+UnicodeString
+MessageFormat::autoQuoteApostrophe(const UnicodeString& pattern, UErrorCode& status) {
+    UnicodeString result;
+    if (U_SUCCESS(status)) {
+        int32_t plen = pattern.length();
+        const char16_t* pat = pattern.getBuffer();
+        int32_t blen = plen * 2 + 1; // space for null termination, convenience
+        char16_t* buf = result.getBuffer(blen);
+        if (buf == nullptr) {
+            status = U_MEMORY_ALLOCATION_ERROR;
+        } else {
+            int32_t len = umsg_autoQuoteApostrophe(pat, plen, buf, blen, &status);
+            result.releaseBuffer(U_SUCCESS(status) ? len : 0);
+        }
+    }
+    if (U_FAILURE(status)) {
+        result.setToBogus();
+    }
+    return result;
+}
+
+// -------------------------------------
+
+static Format* makeRBNF(URBNFRuleSetTag tag, const Locale& locale, const UnicodeString& defaultRuleSet, UErrorCode& ec) {
+    RuleBasedNumberFormat* fmt = new RuleBasedNumberFormat(tag, locale, ec);
+    if (fmt == nullptr) {
+        ec = U_MEMORY_ALLOCATION_ERROR;
+    } else if (U_SUCCESS(ec) && defaultRuleSet.length() > 0) {
+        UErrorCode localStatus = U_ZERO_ERROR; // ignore unrecognized default rule set
+        fmt->setDefaultRuleSet(defaultRuleSet, localStatus);
+    }
+    return fmt;
+}
+
+void MessageFormat::cacheExplicitFormats(UErrorCode& status) {
+    if (U_FAILURE(status)) {
+        return;
+    }
+
+    if (cachedFormatters != nullptr) {
+        uhash_removeAll(cachedFormatters);
+    }
+    if (customFormatArgStarts != nullptr) {
+        uhash_removeAll(customFormatArgStarts);
+    }
+
+    // The last two "parts" can at most be ARG_LIMIT and MSG_LIMIT
+    // which we need not examine.
+    int32_t limit = msgPattern.countParts() - 2;
+    argTypeCount = 0;
+    // We also need not look at the first two "parts"
+    // (at most MSG_START and ARG_START) in this loop.
+    // We determine the argTypeCount first so that we can allocateArgTypes
+    // so that the next loop can set argTypes[argNumber].
+    // (This is for the C API which needs the argTypes to read its va_arg list.)
+    for (int32_t i = 2; i < limit && U_SUCCESS(status); ++i) {
+        const MessagePattern::Part& part = msgPattern.getPart(i);
+        if (part.getType() == UMSGPAT_PART_TYPE_ARG_NUMBER) {
+            const int argNumber = part.getValue();
+            if (argNumber >= argTypeCount) {
+                argTypeCount = argNumber + 1;
+            }
+        }
+    }
+    if (!allocateArgTypes(argTypeCount, status)) {
+        return;
+    }
+    // Set all argTypes to kObject, as a "none" value, for lack of any better value.
+    // We never use kObject for real arguments.
+    // We use it as "no argument yet" for the check for hasArgTypeConflicts.
+    for (int32_t i = 0; i < argTypeCount; ++i) {
+        argTypes[i] = Formattable::kObject;
+    }
+    hasArgTypeConflicts = false;
+
+    // This loop starts at part index 1 because we do need to examine
+    // ARG_START parts. (But we can ignore the MSG_START.)
+    for (int32_t i = 1; i < limit && U_SUCCESS(status); ++i) {
+        const MessagePattern::Part* part = &msgPattern.getPart(i);
+        if (part->getType() != UMSGPAT_PART_TYPE_ARG_START) {
+            continue;
+        }
+        UMessagePatternArgType argType = part->getArgType();
+
+        int32_t argNumber = -1;
+        part = &msgPattern.getPart(i + 1);
+        if (part->getType() == UMSGPAT_PART_TYPE_ARG_NUMBER) {
+            argNumber = part->getValue();
+        }
+        Formattable::Type formattableType;
+
+        switch (argType) {
+        case UMSGPAT_ARG_TYPE_NONE:
+            formattableType = Formattable::kString;
+            break;
+        case UMSGPAT_ARG_TYPE_SIMPLE: {
+            int32_t index = i;
+            i += 2;
+            UnicodeString explicitType = msgPattern.getSubstring(msgPattern.getPart(i++));
+            UnicodeString style;
+            if ((part = &msgPattern.getPart(i))->getType() == UMSGPAT_PART_TYPE_ARG_STYLE) {
+                style = msgPattern.getSubstring(*part);
+                ++i;
+            }
+            UParseError parseError;
+            Format* formatter = createAppropriateFormat(explicitType, style, formattableType, parseError, status);
+            setArgStartFormat(index, formatter, status);
+            break;
+        }
+        case UMSGPAT_ARG_TYPE_CHOICE:
+        case UMSGPAT_ARG_TYPE_PLURAL:
+        case UMSGPAT_ARG_TYPE_SELECTORDINAL:
+            formattableType = Formattable::kDouble;
+            break;
+        case UMSGPAT_ARG_TYPE_SELECT:
+            formattableType = Formattable::kString;
+            break;
+        default:
+            status = U_INTERNAL_PROGRAM_ERROR;  // Should be unreachable.
+            formattableType = Formattable::kString;
+            break;
+        }
+        if (argNumber != -1) {
+            if (argTypes[argNumber] != Formattable::kObject && argTypes[argNumber] != formattableType) {
+                hasArgTypeConflicts = true;
+            }
+            argTypes[argNumber] = formattableType;
+        }
+    }
+}
+
+Format* MessageFormat::createAppropriateFormat(UnicodeString& type, UnicodeString& style,
+                                               Formattable::Type& formattableType, UParseError& parseError,
+                                               UErrorCode& ec) {
+    if (U_FAILURE(ec)) {
+        return nullptr;
+    }
+    Format* fmt = nullptr;
+    int32_t typeID, styleID;
+    DateFormat::EStyle date_style;
+    int32_t firstNonSpace;
+
+    switch (typeID = findKeyword(type, TYPE_IDS)) {
+    case 0: // number
+        formattableType = Formattable::kDouble;
+        switch (findKeyword(style, NUMBER_STYLE_IDS)) {
+        case 0: // default
+            fmt = NumberFormat::createInstance(fLocale, ec);
+            break;
+        case 1: // currency
+            fmt = NumberFormat::createCurrencyInstance(fLocale, ec);
+            break;
+        case 2: // percent
+            fmt = NumberFormat::createPercentInstance(fLocale, ec);
+            break;
+        case 3: // integer
+            formattableType = Formattable::kLong;
+            fmt = createIntegerFormat(fLocale, ec);
+            break;
+        default: // pattern or skeleton
+            firstNonSpace = PatternProps::skipWhiteSpace(style, 0);
+            if (style.compare(firstNonSpace, 2, u"::", 0, 2) == 0) {
+                // Skeleton
+                UnicodeString skeleton = style.tempSubString(firstNonSpace + 2);
+                fmt = number::NumberFormatter::forSkeleton(skeleton, ec).locale(fLocale).toFormat(ec);
+            } else {
+                // Pattern
+                fmt = NumberFormat::createInstance(fLocale, ec);
+                if (fmt) {
+                    auto* decfmt = dynamic_cast<DecimalFormat*>(fmt);
+                    if (decfmt != nullptr) {
+                        decfmt->applyPattern(style, parseError, ec);
+                    }
+                }
+            }
+            break;
+        }
+        break;
+
+    case 1: // date
+    case 2: // time
+        formattableType = Formattable::kDate;
+        firstNonSpace = PatternProps::skipWhiteSpace(style, 0);
+        if (style.compare(firstNonSpace, 2, u"::", 0, 2) == 0) {
+            // Skeleton
+            UnicodeString skeleton = style.tempSubString(firstNonSpace + 2);
+            fmt = DateFormat::createInstanceForSkeleton(skeleton, fLocale, ec);
+        } else {
+            // Pattern
+            styleID = findKeyword(style, DATE_STYLE_IDS);
+            date_style = (styleID >= 0) ? DATE_STYLES[styleID] : DateFormat::kDefault;
+
+            if (typeID == 1) {
+                fmt = DateFormat::createDateInstance(date_style, fLocale);
+            } else {
+                fmt = DateFormat::createTimeInstance(date_style, fLocale);
+            }
+
+            if (styleID < 0 && fmt != nullptr) {
+                SimpleDateFormat* sdtfmt = dynamic_cast<SimpleDateFormat*>(fmt);
+                if (sdtfmt != nullptr) {
+                    sdtfmt->applyPattern(style);
+                }
+            }
+        }
+        break;
+
+    case 3: // spellout
+        formattableType = Formattable::kDouble;
+        fmt = makeRBNF(URBNF_SPELLOUT, fLocale, style, ec);
+        break;
+    case 4: // ordinal
+        formattableType = Formattable::kDouble;
+        fmt = makeRBNF(URBNF_ORDINAL, fLocale, style, ec);
+        break;
+    case 5: // duration
+        formattableType = Formattable::kDouble;
+        fmt = makeRBNF(URBNF_DURATION, fLocale, style, ec);
+        break;
+    default:
+        formattableType = Formattable::kString;
+        ec = U_ILLEGAL_ARGUMENT_ERROR;
+        break;
+    }
+
+    return fmt;
+}
+
+
+//-------------------------------------
+// Finds the string, s, in the string array, list.
+int32_t MessageFormat::findKeyword(const UnicodeString& s,
+                                   const char16_t * const *list)
+{
+    if (s.isEmpty()) {
+        return 0; // default
+    }
+
+    int32_t length = s.length();
+    const char16_t *ps = PatternProps::trimWhiteSpace(s.getBuffer(), length);
+    UnicodeString buffer(false, ps, length);
+    // Trims the space characters and turns all characters
+    // in s to lower case.
+    buffer.toLower("");
+    for (int32_t i = 0; list[i]; ++i) {
+        if (!buffer.compare(list[i], u_strlen(list[i]))) {
+            return i;
+        }
+    }
+    return -1;
+}
+
+/**
+ * Convenience method that ought to be in NumberFormat
+ */
+NumberFormat*
+MessageFormat::createIntegerFormat(const Locale& locale, UErrorCode& status) const {
+    NumberFormat *temp = NumberFormat::createInstance(locale, status);
+    DecimalFormat *temp2;
+    if (temp != nullptr && (temp2 = dynamic_cast<DecimalFormat*>(temp)) != nullptr) {
+        temp2->setMaximumFractionDigits(0);
+        temp2->setDecimalSeparatorAlwaysShown(false);
+        temp2->setParseIntegerOnly(true);
+    }
+
+    return temp;
+}
+
+/**
+ * Return the default number format.  Used to format a numeric
+ * argument when subformats[i].format is nullptr.  Returns nullptr
+ * on failure.
+ *
+ * Semantically const but may modify *this.
+ */
+const NumberFormat* MessageFormat::getDefaultNumberFormat(UErrorCode& ec) const {
+    if (defaultNumberFormat == nullptr) {
+        MessageFormat* t = (MessageFormat*) this;
+        t->defaultNumberFormat = NumberFormat::createInstance(fLocale, ec);
+        if (U_FAILURE(ec)) {
+            delete t->defaultNumberFormat;
+            t->defaultNumberFormat = nullptr;
+        } else if (t->defaultNumberFormat == nullptr) {
+            ec = U_MEMORY_ALLOCATION_ERROR;
+        }
+    }
+    return defaultNumberFormat;
+}
+
+/**
+ * Return the default date format.  Used to format a date
+ * argument when subformats[i].format is nullptr.  Returns nullptr
+ * on failure.
+ *
+ * Semantically const but may modify *this.
+ */
+const DateFormat* MessageFormat::getDefaultDateFormat(UErrorCode& ec) const {
+    if (defaultDateFormat == nullptr) {
+        MessageFormat* t = (MessageFormat*) this;
+        t->defaultDateFormat = DateFormat::createDateTimeInstance(DateFormat::kShort, DateFormat::kShort, fLocale);
+        if (t->defaultDateFormat == nullptr) {
+            ec = U_MEMORY_ALLOCATION_ERROR;
+        }
+    }
+    return defaultDateFormat;
+}
+
+UBool
+MessageFormat::usesNamedArguments() const {
+    return msgPattern.hasNamedArguments();
+}
+
+int32_t
+MessageFormat::getArgTypeCount() const {
+    return argTypeCount;
+}
+
+UBool MessageFormat::equalFormats(const void* left, const void* right) {
+    return *(const Format*)left==*(const Format*)right;
+}
+
+
+bool MessageFormat::DummyFormat::operator==(const Format&) const {
+    return true;
+}
+
+MessageFormat::DummyFormat* MessageFormat::DummyFormat::clone() const {
+    return new DummyFormat();
+}
+
+UnicodeString& MessageFormat::DummyFormat::format(const Formattable&,
+                          UnicodeString& appendTo,
+                          UErrorCode& status) const {
+    if (U_SUCCESS(status)) {
+        status = U_UNSUPPORTED_ERROR;
+    }
+    return appendTo;
+}
+
+UnicodeString& MessageFormat::DummyFormat::format(const Formattable&,
+                          UnicodeString& appendTo,
+                          FieldPosition&,
+                          UErrorCode& status) const {
+    if (U_SUCCESS(status)) {
+        status = U_UNSUPPORTED_ERROR;
+    }
+    return appendTo;
+}
+
+UnicodeString& MessageFormat::DummyFormat::format(const Formattable&,
+                          UnicodeString& appendTo,
+                          FieldPositionIterator*,
+                          UErrorCode& status) const {
+    if (U_SUCCESS(status)) {
+        status = U_UNSUPPORTED_ERROR;
+    }
+    return appendTo;
+}
+
+void MessageFormat::DummyFormat::parseObject(const UnicodeString&,
+                                                     Formattable&,
+                                                     ParsePosition& ) const {
+}
+
+
+FormatNameEnumeration::FormatNameEnumeration(LocalPointer<UVector> nameList, UErrorCode& /*status*/) {
+    pos=0;
+    fFormatNames = std::move(nameList);
+}
+
+const UnicodeString*
+FormatNameEnumeration::snext(UErrorCode& status) {
+    if (U_SUCCESS(status) && pos < fFormatNames->size()) {
+        return (const UnicodeString*)fFormatNames->elementAt(pos++);
+    }
+    return nullptr;
+}
+
+void
+FormatNameEnumeration::reset(UErrorCode& /*status*/) {
+    pos=0;
+}
+
+int32_t
+FormatNameEnumeration::count(UErrorCode& /*status*/) const {
+    return (fFormatNames==nullptr) ? 0 : fFormatNames->size();
+}
+
+FormatNameEnumeration::~FormatNameEnumeration() {
+}
+
+MessageFormat::PluralSelectorProvider::PluralSelectorProvider(const MessageFormat &mf, UPluralType t)
+        : msgFormat(mf), rules(nullptr), type(t) {
+}
+
+MessageFormat::PluralSelectorProvider::~PluralSelectorProvider() {
+    delete rules;
+}
+
+UnicodeString MessageFormat::PluralSelectorProvider::select(void *ctx, double number,
+                                                            UErrorCode& ec) const {
+    if (U_FAILURE(ec)) {
+        return UnicodeString(false, OTHER_STRING, 5);
+    }
+    MessageFormat::PluralSelectorProvider* t = const_cast<MessageFormat::PluralSelectorProvider*>(this);
+    if(rules == nullptr) {
+        t->rules = PluralRules::forLocale(msgFormat.fLocale, type, ec);
+        if (U_FAILURE(ec)) {
+            return UnicodeString(false, OTHER_STRING, 5);
+        }
+    }
+    // Select a sub-message according to how the number is formatted,
+    // which is specified in the selected sub-message.
+    // We avoid this circle by looking at how
+    // the number is formatted in the "other" sub-message
+    // which must always be present and usually contains the number.
+    // Message authors should be consistent across sub-messages.
+    PluralSelectorContext &context = *static_cast<PluralSelectorContext *>(ctx);
+    int32_t otherIndex = msgFormat.findOtherSubMessage(context.startIndex);
+    context.numberArgIndex = msgFormat.findFirstPluralNumberArg(otherIndex, context.argName);
+    if(context.numberArgIndex > 0 && msgFormat.cachedFormatters != nullptr) {
+        context.formatter =
+            (const Format*)uhash_iget(msgFormat.cachedFormatters, context.numberArgIndex);
+    }
+    if(context.formatter == nullptr) {
+        context.formatter = msgFormat.getDefaultNumberFormat(ec);
+        context.forReplaceNumber = true;
+    }
+    if (context.number.getDouble(ec) != number) {
+        ec = U_INTERNAL_PROGRAM_ERROR;
+        return UnicodeString(false, OTHER_STRING, 5);
+    }
+    context.formatter->format(context.number, context.numberString, ec);
+    auto* decFmt = dynamic_cast<const DecimalFormat *>(context.formatter);
+    if(decFmt != nullptr) {
+        number::impl::DecimalQuantity dq;
+        decFmt->formatToDecimalQuantity(context.number, dq, ec);
+        if (U_FAILURE(ec)) {
+            return UnicodeString(false, OTHER_STRING, 5);
+        }
+        return rules->select(dq);
+    } else {
+        return rules->select(number);
+    }
+}
+
+void MessageFormat::PluralSelectorProvider::reset() {
+    delete rules;
+    rules = nullptr;
+}
+
+
+U_NAMESPACE_END
+
+#endif /* #if !UCONFIG_NO_FORMATTING */
+
+//eof