--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/CSP2/CSP2_env/env-d9b9114564458d9d-741b3de822f2aaca6c6caa4325c4afce/include/unicode/msgfmt.h	Tue Mar 18 17:55:14 2025 -0400
@@ -0,0 +1,1119 @@
+// © 2016 and later: Unicode, Inc. and others.
+// License & terms of use: http://www.unicode.org/copyright.html
+/*
+* Copyright (C) 2007-2013, International Business Machines Corporation and
+* others. All Rights Reserved.
+********************************************************************************
+*
+* File MSGFMT.H
+*
+* Modification History:
+*
+*   Date        Name        Description
+*   02/19/97    aliu        Converted from java.
+*   03/20/97    helena      Finished first cut of implementation.
+*   07/22/98    stephen     Removed operator!= (defined in Format)
+*   08/19/2002  srl         Removing Javaisms
+*******************************************************************************/
+
+#ifndef MSGFMT_H
+#define MSGFMT_H
+
+#include "unicode/utypes.h"
+
+#if U_SHOW_CPLUSPLUS_API
+
+/**
+ * \file
+ * \brief C++ API: Formats messages in a language-neutral way.
+ */
+
+#if !UCONFIG_NO_FORMATTING
+
+#include "unicode/format.h"
+#include "unicode/locid.h"
+#include "unicode/messagepattern.h"
+#include "unicode/parseerr.h"
+#include "unicode/plurfmt.h"
+#include "unicode/plurrule.h"
+
+U_CDECL_BEGIN
+// Forward declaration.
+struct UHashtable;
+typedef struct UHashtable UHashtable; /**< @internal */
+U_CDECL_END
+
+U_NAMESPACE_BEGIN
+
+class AppendableWrapper;
+class DateFormat;
+class NumberFormat;
+
+/**
+ * <p>MessageFormat prepares strings for display to users,
+ * with optional arguments (variables/placeholders).
+ * The arguments can occur in any order, which is necessary for translation
+ * into languages with different grammars.
+ *
+ * <p>A MessageFormat is constructed from a <em>pattern</em> string
+ * with arguments in {curly braces} which will be replaced by formatted values.
+ *
+ * <p><code>MessageFormat</code> differs from the other <code>Format</code>
+ * classes in that you create a <code>MessageFormat</code> object with one
+ * of its constructors (not with a <code>createInstance</code> style factory
+ * method). Factory methods aren't necessary because <code>MessageFormat</code>
+ * itself doesn't implement locale-specific behavior. Any locale-specific
+ * behavior is defined by the pattern that you provide and the
+ * subformats used for inserted arguments.
+ *
+ * <p>Arguments can be named (using identifiers) or numbered (using small ASCII-digit integers).
+ * Some of the API methods work only with argument numbers and throw an exception
+ * if the pattern has named arguments (see {@link #usesNamedArguments()}).
+ *
+ * <p>An argument might not specify any format type. In this case,
+ * a numeric value is formatted with a default (for the locale) NumberFormat,
+ * and a date/time value is formatted with a default (for the locale) DateFormat.
+ *
+ * <p>An argument might specify a "simple" type for which the specified
+ * Format object is created, cached and used.
+ *
+ * <p>An argument might have a "complex" type with nested MessageFormat sub-patterns.
+ * During formatting, one of these sub-messages is selected according to the argument value
+ * and recursively formatted.
+ *
+ * <p>After construction, a custom Format object can be set for
+ * a top-level argument, overriding the default formatting and parsing behavior
+ * for that argument.
+ * However, custom formatting can be achieved more simply by writing
+ * a typeless argument in the pattern string
+ * and supplying it with a preformatted string value.
+ *
+ * <p>When formatting, MessageFormat takes a collection of argument values
+ * and writes an output string.
+ * The argument values may be passed as an array
+ * (when the pattern contains only numbered arguments)
+ * or as an array of names and and an array of arguments (which works for both named
+ * and numbered arguments).
+ *
+ * <p>Each argument is matched with one of the input values by array index or argument name
+ * and formatted according to its pattern specification
+ * (or using a custom Format object if one was set).
+ * A numbered pattern argument is matched with an argument name that contains that number
+ * as an ASCII-decimal-digit string (without leading zero).
+ *
+ * <h4><a name="patterns">Patterns and Their Interpretation</a></h4>
+ *
+ * <code>MessageFormat</code> uses patterns of the following form:
+ * <pre>
+ * message = messageText (argument messageText)*
+ * argument = noneArg | simpleArg | complexArg
+ * complexArg = choiceArg | pluralArg | selectArg | selectordinalArg
+ *
+ * noneArg = '{' argNameOrNumber '}'
+ * simpleArg = '{' argNameOrNumber ',' argType [',' argStyle] '}'
+ * choiceArg = '{' argNameOrNumber ',' "choice" ',' choiceStyle '}'
+ * pluralArg = '{' argNameOrNumber ',' "plural" ',' pluralStyle '}'
+ * selectArg = '{' argNameOrNumber ',' "select" ',' selectStyle '}'
+ * selectordinalArg = '{' argNameOrNumber ',' "selectordinal" ',' pluralStyle '}'
+ *
+ * choiceStyle: see {@link ChoiceFormat}
+ * pluralStyle: see {@link PluralFormat}
+ * selectStyle: see {@link SelectFormat}
+ *
+ * argNameOrNumber = argName | argNumber
+ * argName = [^[[:Pattern_Syntax:][:Pattern_White_Space:]]]+
+ * argNumber = '0' | ('1'..'9' ('0'..'9')*)
+ *
+ * argType = "number" | "date" | "time" | "spellout" | "ordinal" | "duration"
+ * argStyle = "short" | "medium" | "long" | "full" | "integer" | "currency" | "percent" | argStyleText | "::" argSkeletonText
+ * </pre>
+ *
+ * <ul>
+ *   <li>messageText can contain quoted literal strings including syntax characters.
+ *       A quoted literal string begins with an ASCII apostrophe and a syntax character
+ *       (usually a {curly brace}) and continues until the next single apostrophe.
+ *       A double ASCII apostrohpe inside or outside of a quoted string represents
+ *       one literal apostrophe.
+ *   <li>Quotable syntax characters are the {curly braces} in all messageText parts,
+ *       plus the '#' sign in a messageText immediately inside a pluralStyle,
+ *       and the '|' symbol in a messageText immediately inside a choiceStyle.
+ *   <li>See also {@link #UMessagePatternApostropheMode}
+ *   <li>In argStyleText, every single ASCII apostrophe begins and ends quoted literal text,
+ *       and unquoted {curly braces} must occur in matched pairs.
+ * </ul>
+ *
+ * <p>Recommendation: Use the real apostrophe (single quote) character
+ * \htmlonly&#x2019;\endhtmlonly (U+2019) for
+ * human-readable text, and use the ASCII apostrophe ' (U+0027)
+ * only in program syntax, like quoting in MessageFormat.
+ * See the annotations for U+0027 Apostrophe in The Unicode Standard.
+ *
+ * <p>The <code>choice</code> argument type is deprecated.
+ * Use <code>plural</code> arguments for proper plural selection,
+ * and <code>select</code> arguments for simple selection among a fixed set of choices.
+ *
+ * <p>The <code>argType</code> and <code>argStyle</code> values are used to create
+ * a <code>Format</code> instance for the format element. The following
+ * table shows how the values map to Format instances. Combinations not
+ * shown in the table are illegal. Any <code>argStyleText</code> must
+ * be a valid pattern string for the Format subclass used.
+ *
+ * <p><table border=1>
+ *    <tr>
+ *       <th>argType
+ *       <th>argStyle
+ *       <th>resulting Format object
+ *    <tr>
+ *       <td colspan=2><i>(none)</i>
+ *       <td><code>null</code>
+ *    <tr>
+ *       <td rowspan=6><code>number</code>
+ *       <td><i>(none)</i>
+ *       <td><code>NumberFormat.createInstance(getLocale(), status)</code>
+ *    <tr>
+ *       <td><code>integer</code>
+ *       <td><code>NumberFormat.createInstance(getLocale(), kNumberStyle, status)</code>
+ *    <tr>
+ *       <td><code>currency</code>
+ *       <td><code>NumberFormat.createCurrencyInstance(getLocale(), status)</code>
+ *    <tr>
+ *       <td><code>percent</code>
+ *       <td><code>NumberFormat.createPercentInstance(getLocale(), status)</code>
+ *    <tr>
+ *       <td><i>argStyleText</i>
+ *       <td><code>new DecimalFormat(argStyleText, new DecimalFormatSymbols(getLocale(), status), status)</code>
+ *    <tr>
+ *       <td><i>argSkeletonText</i>
+ *       <td><code>NumberFormatter::forSkeleton(argSkeletonText, status).locale(getLocale()).toFormat(status)</code>
+ *    <tr>
+ *       <td rowspan=7><code>date</code>
+ *       <td><i>(none)</i>
+ *       <td><code>DateFormat.createDateInstance(kDefault, getLocale(), status)</code>
+ *    <tr>
+ *       <td><code>short</code>
+ *       <td><code>DateFormat.createDateInstance(kShort, getLocale(), status)</code>
+ *    <tr>
+ *       <td><code>medium</code>
+ *       <td><code>DateFormat.createDateInstance(kDefault, getLocale(), status)</code>
+ *    <tr>
+ *       <td><code>long</code>
+ *       <td><code>DateFormat.createDateInstance(kLong, getLocale(), status)</code>
+ *    <tr>
+ *       <td><code>full</code>
+ *       <td><code>DateFormat.createDateInstance(kFull, getLocale(), status)</code>
+ *    <tr>
+ *       <td><i>argStyleText</i>
+ *       <td><code>new SimpleDateFormat(argStyleText, getLocale(), status)</code>
+ *    <tr>
+ *       <td><i>argSkeletonText</i>
+ *       <td><code>DateFormat::createInstanceForSkeleton(argSkeletonText, getLocale(), status)</code>
+ *    <tr>
+ *       <td rowspan=6><code>time</code>
+ *       <td><i>(none)</i>
+ *       <td><code>DateFormat.createTimeInstance(kDefault, getLocale(), status)</code>
+ *    <tr>
+ *       <td><code>short</code>
+ *       <td><code>DateFormat.createTimeInstance(kShort, getLocale(), status)</code>
+ *    <tr>
+ *       <td><code>medium</code>
+ *       <td><code>DateFormat.createTimeInstance(kDefault, getLocale(), status)</code>
+ *    <tr>
+ *       <td><code>long</code>
+ *       <td><code>DateFormat.createTimeInstance(kLong, getLocale(), status)</code>
+ *    <tr>
+ *       <td><code>full</code>
+ *       <td><code>DateFormat.createTimeInstance(kFull, getLocale(), status)</code>
+ *    <tr>
+ *       <td><i>argStyleText</i>
+ *       <td><code>new SimpleDateFormat(argStyleText, getLocale(), status)</code>
+ *    <tr>
+ *       <td><code>spellout</code>
+ *       <td><i>argStyleText (optional)</i>
+ *       <td><code>new RuleBasedNumberFormat(URBNF_SPELLOUT, getLocale(), status)
+ *           <br/>&nbsp;&nbsp;&nbsp;&nbsp;.setDefaultRuleset(argStyleText, status);</code>
+ *    <tr>
+ *       <td><code>ordinal</code>
+ *       <td><i>argStyleText (optional)</i>
+ *       <td><code>new RuleBasedNumberFormat(URBNF_ORDINAL, getLocale(), status)
+ *           <br/>&nbsp;&nbsp;&nbsp;&nbsp;.setDefaultRuleset(argStyleText, status);</code>
+ *    <tr>
+ *       <td><code>duration</code>
+ *       <td><i>argStyleText (optional)</i>
+ *       <td><code>new RuleBasedNumberFormat(URBNF_DURATION, getLocale(), status)
+ *           <br/>&nbsp;&nbsp;&nbsp;&nbsp;.setDefaultRuleset(argStyleText, status);</code>
+ * </table>
+ * <p>
+ *
+ * <h4>Argument formatting</h4>
+ *
+ * <p>Arguments are formatted according to their type, using the default
+ * ICU formatters for those types, unless otherwise specified.</p>
+ *
+ * <p>There are also several ways to control the formatting.</p>
+ *
+ * <p>We recommend you use default styles, predefined style values, skeletons,
+ * or preformatted values, but not pattern strings or custom format objects.</p>
+ *
+ * <p>For more details, see the
+ * <a href="http://userguide.icu-project.org/formatparse/messages">ICU User Guide</a>.</p>
+ *
+ * <h4>Usage Information</h4>
+ *
+ * <p>Here are some examples of usage:
+ * Example 1:
+ *
+ * <pre>
+ * \code
+ *     UErrorCode success = U_ZERO_ERROR;
+ *     GregorianCalendar cal(success);
+ *     Formattable arguments[] = {
+ *         7L,
+ *         Formattable( (Date) cal.getTime(success), Formattable::kIsDate),
+ *         "a disturbance in the Force"
+ *     };
+ *
+ *     UnicodeString result;
+ *     MessageFormat::format(
+ *          "At {1,time,::jmm} on {1,date,::dMMMM}, there was {2} on planet {0,number}.",
+ *          arguments, 3, result, success );
+ *
+ *     cout << "result: " << result << endl;
+ *     //<output>: At 4:34 PM on March 23, there was a disturbance
+ *     //             in the Force on planet 7.
+ * \endcode
+ * </pre>
+ *
+ * Typically, the message format will come from resources, and the
+ * arguments will be dynamically set at runtime.
+ *
+ * <p>Example 2:
+ *
+ * <pre>
+ *  \code
+ *     success = U_ZERO_ERROR;
+ *     Formattable testArgs[] = {3L, "MyDisk"};
+ *
+ *     MessageFormat form(
+ *         "The disk \"{1}\" contains {0} file(s).", success );
+ *
+ *     UnicodeString string;
+ *     FieldPosition fpos = 0;
+ *     cout << "format: " << form.format(testArgs, 2, string, fpos, success ) << endl;
+ *
+ *     // output, with different testArgs:
+ *     // output: The disk "MyDisk" contains 0 file(s).
+ *     // output: The disk "MyDisk" contains 1 file(s).
+ *     // output: The disk "MyDisk" contains 1,273 file(s).
+ *  \endcode
+ *  </pre>
+ *
+ *
+ * <p>For messages that include plural forms, you can use a plural argument:
+ * <pre>
+ * \code
+ *  success = U_ZERO_ERROR;
+ *  MessageFormat msgFmt(
+ *       "{num_files, plural, "
+ *       "=0{There are no files on disk \"{disk_name}\".}"
+ *       "=1{There is one file on disk \"{disk_name}\".}"
+ *       "other{There are # files on disk \"{disk_name}\".}}",
+ *      Locale("en"),
+ *      success);
+ *  FieldPosition fpos = 0;
+ *  Formattable testArgs[] = {0L, "MyDisk"};
+ *  UnicodeString testArgsNames[] = {"num_files", "disk_name"};
+ *  UnicodeString result;
+ *  cout << msgFmt.format(testArgs, testArgsNames, 2, result, fpos, 0, success);
+ *  testArgs[0] = 3L;
+ *  cout << msgFmt.format(testArgs, testArgsNames, 2, result, fpos, 0, success);
+ * \endcode
+ * <em>output</em>:
+ * There are no files on disk "MyDisk".
+ * There are 3 files on "MyDisk".
+ * </pre>
+ * See {@link PluralFormat} and {@link PluralRules} for details.
+ *
+ * <h4><a name="synchronization">Synchronization</a></h4>
+ *
+ * <p>MessageFormats are not synchronized.
+ * It is recommended to create separate format instances for each thread.
+ * If multiple threads access a format concurrently, it must be synchronized
+ * externally.
+ *
+ * @stable ICU 2.0
+ */
+class U_I18N_API MessageFormat : public Format {
+public:
+#ifndef U_HIDE_OBSOLETE_API
+    /**
+     * Enum type for kMaxFormat.
+     * @obsolete ICU 3.0.  The 10-argument limit was removed as of ICU 2.6,
+     * rendering this enum type obsolete.
+     */
+    enum EFormatNumber {
+        /**
+         * The maximum number of arguments.
+         * @obsolete ICU 3.0.  The 10-argument limit was removed as of ICU 2.6,
+         * rendering this constant obsolete.
+         */
+        kMaxFormat = 10
+    };
+#endif  /* U_HIDE_OBSOLETE_API */
+
+    /**
+     * Constructs a new MessageFormat using the given pattern and the
+     * default locale.
+     *
+     * @param pattern   Pattern used to construct object.
+     * @param status    Input/output error code.  If the
+     *                  pattern cannot be parsed, set to failure code.
+     * @stable ICU 2.0
+     */
+    MessageFormat(const UnicodeString& pattern,
+                  UErrorCode &status);
+
+    /**
+     * Constructs a new MessageFormat using the given pattern and locale.
+     * @param pattern   Pattern used to construct object.
+     * @param newLocale The locale to use for formatting dates and numbers.
+     * @param status    Input/output error code.  If the
+     *                  pattern cannot be parsed, set to failure code.
+     * @stable ICU 2.0
+     */
+    MessageFormat(const UnicodeString& pattern,
+                  const Locale& newLocale,
+                        UErrorCode& status);
+    /**
+     * Constructs a new MessageFormat using the given pattern and locale.
+     * @param pattern   Pattern used to construct object.
+     * @param newLocale The locale to use for formatting dates and numbers.
+     * @param parseError Struct to receive information on the position
+     *                   of an error within the pattern.
+     * @param status    Input/output error code.  If the
+     *                  pattern cannot be parsed, set to failure code.
+     * @stable ICU 2.0
+     */
+    MessageFormat(const UnicodeString& pattern,
+                  const Locale& newLocale,
+                  UParseError& parseError,
+                  UErrorCode& status);
+    /**
+     * Constructs a new MessageFormat from an existing one.
+     * @stable ICU 2.0
+     */
+    MessageFormat(const MessageFormat&);
+
+    /**
+     * Assignment operator.
+     * @stable ICU 2.0
+     */
+    const MessageFormat& operator=(const MessageFormat&);
+
+    /**
+     * Destructor.
+     * @stable ICU 2.0
+     */
+    virtual ~MessageFormat();
+
+    /**
+     * Clones this Format object polymorphically.  The caller owns the
+     * result and should delete it when done.
+     * @stable ICU 2.0
+     */
+    virtual MessageFormat* clone() const;
+
+    /**
+     * Returns true if the given Format objects are semantically equal.
+     * Objects of different subclasses are considered unequal.
+     * @param other  the object to be compared with.
+     * @return       true if the given Format objects are semantically equal.
+     * @stable ICU 2.0
+     */
+    virtual UBool operator==(const Format& other) const;
+
+    /**
+     * Sets the locale to be used for creating argument Format objects.
+     * @param theLocale    the new locale value to be set.
+     * @stable ICU 2.0
+     */
+    virtual void setLocale(const Locale& theLocale);
+
+    /**
+     * Gets the locale used for creating argument Format objects.
+     * format information.
+     * @return    the locale of the object.
+     * @stable ICU 2.0
+     */
+    virtual const Locale& getLocale(void) const;
+
+    /**
+     * Applies the given pattern string to this message format.
+     *
+     * @param pattern   The pattern to be applied.
+     * @param status    Input/output error code.  If the
+     *                  pattern cannot be parsed, set to failure code.
+     * @stable ICU 2.0
+     */
+    virtual void applyPattern(const UnicodeString& pattern,
+                              UErrorCode& status);
+    /**
+     * Applies the given pattern string to this message format.
+     *
+     * @param pattern    The pattern to be applied.
+     * @param parseError Struct to receive information on the position
+     *                   of an error within the pattern.
+     * @param status    Input/output error code.  If the
+     *                  pattern cannot be parsed, set to failure code.
+     * @stable ICU 2.0
+     */
+    virtual void applyPattern(const UnicodeString& pattern,
+                             UParseError& parseError,
+                             UErrorCode& status);
+
+    /**
+     * Sets the UMessagePatternApostropheMode and the pattern used by this message format.
+     * Parses the pattern and caches Format objects for simple argument types.
+     * Patterns and their interpretation are specified in the
+     * <a href="#patterns">class description</a>.
+     * <p>
+     * This method is best used only once on a given object to avoid confusion about the mode,
+     * and after constructing the object with an empty pattern string to minimize overhead.
+     *
+     * @param pattern    The pattern to be applied.
+     * @param aposMode   The new apostrophe mode.
+     * @param parseError Struct to receive information on the position
+     *                   of an error within the pattern.
+     *                   Can be NULL.
+     * @param status    Input/output error code.  If the
+     *                  pattern cannot be parsed, set to failure code.
+     * @stable ICU 4.8
+     */
+    virtual void applyPattern(const UnicodeString& pattern,
+                              UMessagePatternApostropheMode aposMode,
+                              UParseError* parseError,
+                              UErrorCode& status);
+
+    /**
+     * @return this instance's UMessagePatternApostropheMode.
+     * @stable ICU 4.8
+     */
+    UMessagePatternApostropheMode getApostropheMode() const {
+        return msgPattern.getApostropheMode();
+    }
+
+    /**
+     * Returns a pattern that can be used to recreate this object.
+     *
+     * @param appendTo  Output parameter to receive the pattern.
+     *                  Result is appended to existing contents.
+     * @return          Reference to 'appendTo' parameter.
+     * @stable ICU 2.0
+     */
+    virtual UnicodeString& toPattern(UnicodeString& appendTo) const;
+
+    /**
+     * Sets subformats.
+     * See the class description about format numbering.
+     * The caller should not delete the Format objects after this call.
+     * <EM>The array formatsToAdopt is not itself adopted.</EM> Its
+     * ownership is retained by the caller. If the call fails because
+     * memory cannot be allocated, then the formats will be deleted
+     * by this method, and this object will remain unchanged.
+     *
+     * <p>If this format uses named arguments, the new formats are discarded
+     * and this format remains unchanged.
+     *
+     * @stable ICU 2.0
+     * @param formatsToAdopt    the format to be adopted.
+     * @param count             the size of the array.
+     */
+    virtual void adoptFormats(Format** formatsToAdopt, int32_t count);
+
+    /**
+     * Sets subformats.
+     * See the class description about format numbering.
+     * Each item in the array is cloned into the internal array.
+     * If the call fails because memory cannot be allocated, then this
+     * object will remain unchanged.
+     *
+     * <p>If this format uses named arguments, the new formats are discarded
+     * and this format remains unchanged.
+     *
+     * @stable ICU 2.0
+     * @param newFormats the new format to be set.
+     * @param cnt        the size of the array.
+     */
+    virtual void setFormats(const Format** newFormats, int32_t cnt);
+
+
+    /**
+     * Sets one subformat.
+     * See the class description about format numbering.
+     * The caller should not delete the Format object after this call.
+     * If the number is over the number of formats already set,
+     * the item will be deleted and ignored.
+     *
+     * <p>If this format uses named arguments, the new format is discarded
+     * and this format remains unchanged.
+     *
+     * @stable ICU 2.0
+     * @param formatNumber     index of the subformat.
+     * @param formatToAdopt    the format to be adopted.
+     */
+    virtual void adoptFormat(int32_t formatNumber, Format* formatToAdopt);
+
+    /**
+     * Sets one subformat.
+     * See the class description about format numbering.
+     * If the number is over the number of formats already set,
+     * the item will be ignored.
+     * @param formatNumber     index of the subformat.
+     * @param format    the format to be set.
+     * @stable ICU 2.0
+     */
+    virtual void setFormat(int32_t formatNumber, const Format& format);
+
+    /**
+     * Gets format names. This function returns formatNames in StringEnumerations
+     * which can be used with getFormat() and setFormat() to export formattable
+     * array from current MessageFormat to another.  It is the caller's responsibility
+     * to delete the returned formatNames.
+     * @param status  output param set to success/failure code.
+     * @stable ICU 4.0
+     */
+    virtual StringEnumeration* getFormatNames(UErrorCode& status);
+
+    /**
+     * Gets subformat pointer for given format name.
+     * This function supports both named and numbered
+     * arguments. If numbered, the formatName is the
+     * corresponding UnicodeStrings (e.g. "0", "1", "2"...).
+     * The returned Format object should not be deleted by the caller,
+     * nor should the ponter of other object .  The pointer and its
+     * contents remain valid only until the next call to any method
+     * of this class is made with this object.
+     * @param formatName the name or number specifying a format
+     * @param status  output param set to success/failure code.
+     * @stable ICU 4.0
+     */
+    virtual Format* getFormat(const UnicodeString& formatName, UErrorCode& status);
+
+    /**
+     * Sets one subformat for given format name.
+     * See the class description about format name.
+     * This function supports both named and numbered
+     * arguments-- if numbered, the formatName is the
+     * corresponding UnicodeStrings (e.g. "0", "1", "2"...).
+     * If there is no matched formatName or wrong type,
+     * the item will be ignored.
+     * @param formatName  Name of the subformat.
+     * @param format      the format to be set.
+     * @param status  output param set to success/failure code.
+     * @stable ICU 4.0
+     */
+    virtual void setFormat(const UnicodeString& formatName, const Format& format, UErrorCode& status);
+
+    /**
+     * Sets one subformat for given format name.
+     * See the class description about format name.
+     * This function supports both named and numbered
+     * arguments-- if numbered, the formatName is the
+     * corresponding UnicodeStrings (e.g. "0", "1", "2"...).
+     * If there is no matched formatName or wrong type,
+     * the item will be ignored.
+     * The caller should not delete the Format object after this call.
+     * @param formatName  Name of the subformat.
+     * @param formatToAdopt  Format to be adopted.
+     * @param status      output param set to success/failure code.
+     * @stable ICU 4.0
+     */
+    virtual void adoptFormat(const UnicodeString& formatName, Format* formatToAdopt, UErrorCode& status);
+
+    /**
+     * Gets an array of subformats of this object.  The returned array
+     * should not be deleted by the caller, nor should the pointers
+     * within the array.  The array and its contents remain valid only
+     * until the next call to this format. See the class description
+     * about format numbering.
+     *
+     * @param count output parameter to receive the size of the array
+     * @return an array of count Format* objects, or NULL if out of
+     * memory.  Any or all of the array elements may be NULL.
+     * @stable ICU 2.0
+     */
+    virtual const Format** getFormats(int32_t& count) const;
+
+
+    using Format::format;
+
+    /**
+     * Formats the given array of arguments into a user-readable string.
+     * Does not take ownership of the Formattable* array or its contents.
+     *
+     * <p>If this format uses named arguments, appendTo is unchanged and
+     * status is set to U_ILLEGAL_ARGUMENT_ERROR.
+     *
+     * @param source    An array of objects to be formatted.
+     * @param count     The number of elements of 'source'.
+     * @param appendTo  Output parameter to receive result.
+     *                  Result is appended to existing contents.
+     * @param ignore    Not used; inherited from base class API.
+     * @param status    Input/output error code.  If the
+     *                  pattern cannot be parsed, set to failure code.
+     * @return          Reference to 'appendTo' parameter.
+     * @stable ICU 2.0
+     */
+    UnicodeString& format(const Formattable* source,
+                          int32_t count,
+                          UnicodeString& appendTo,
+                          FieldPosition& ignore,
+                          UErrorCode& status) const;
+
+    /**
+     * Formats the given array of arguments into a user-readable string
+     * using the given pattern.
+     *
+     * <p>If this format uses named arguments, appendTo is unchanged and
+     * status is set to U_ILLEGAL_ARGUMENT_ERROR.
+     *
+     * @param pattern   The pattern.
+     * @param arguments An array of objects to be formatted.
+     * @param count     The number of elements of 'source'.
+     * @param appendTo  Output parameter to receive result.
+     *                  Result is appended to existing contents.
+     * @param status    Input/output error code.  If the
+     *                  pattern cannot be parsed, set to failure code.
+     * @return          Reference to 'appendTo' parameter.
+     * @stable ICU 2.0
+     */
+    static UnicodeString& format(const UnicodeString& pattern,
+                                 const Formattable* arguments,
+                                 int32_t count,
+                                 UnicodeString& appendTo,
+                                 UErrorCode& status);
+
+    /**
+     * Formats the given array of arguments into a user-readable
+     * string.  The array must be stored within a single Formattable
+     * object of type kArray. If the Formattable object type is not of
+     * type kArray, then returns a failing UErrorCode.
+     *
+     * <p>If this format uses named arguments, appendTo is unchanged and
+     * status is set to U_ILLEGAL_ARGUMENT_ERROR.
+     *
+     * @param obj       A Formattable of type kArray containing
+     *                  arguments to be formatted.
+     * @param appendTo  Output parameter to receive result.
+     *                  Result is appended to existing contents.
+     * @param pos       On input: an alignment field, if desired.
+     *                  On output: the offsets of the alignment field.
+     * @param status    Input/output error code.  If the
+     *                  pattern cannot be parsed, set to failure code.
+     * @return          Reference to 'appendTo' parameter.
+     * @stable ICU 2.0
+     */
+    virtual UnicodeString& format(const Formattable& obj,
+                                  UnicodeString& appendTo,
+                                  FieldPosition& pos,
+                                  UErrorCode& status) const;
+
+    /**
+     * Formats the given array of arguments into a user-defined argument name
+     * array. This function supports both named and numbered
+     * arguments-- if numbered, the formatName is the
+     * corresponding UnicodeStrings (e.g. "0", "1", "2"...).
+     *
+     * @param argumentNames argument name array
+     * @param arguments An array of objects to be formatted.
+     * @param count     The number of elements of 'argumentNames' and
+     *                  arguments.  The number of argumentNames and arguments
+     *                  must be the same.
+     * @param appendTo  Output parameter to receive result.
+     *                  Result is appended to existing contents.
+     * @param status    Input/output error code.  If the
+     *                  pattern cannot be parsed, set to failure code.
+     * @return          Reference to 'appendTo' parameter.
+     * @stable ICU 4.0
+     */
+    UnicodeString& format(const UnicodeString* argumentNames,
+                          const Formattable* arguments,
+                          int32_t count,
+                          UnicodeString& appendTo,
+                          UErrorCode& status) const;
+    /**
+     * Parses the given string into an array of output arguments.
+     *
+     * @param source    String to be parsed.
+     * @param pos       On input, starting position for parse. On output,
+     *                  final position after parse.  Unchanged if parse
+     *                  fails.
+     * @param count     Output parameter to receive the number of arguments
+     *                  parsed.
+     * @return an array of parsed arguments.  The caller owns both
+     * the array and its contents.
+     * @stable ICU 2.0
+     */
+    virtual Formattable* parse(const UnicodeString& source,
+                               ParsePosition& pos,
+                               int32_t& count) const;
+
+    /**
+     * Parses the given string into an array of output arguments.
+     *
+     * <p>If this format uses named arguments, status is set to
+     * U_ARGUMENT_TYPE_MISMATCH.
+     *
+     * @param source    String to be parsed.
+     * @param count     Output param to receive size of returned array.
+     * @param status    Input/output error code.  If the
+     *                  pattern cannot be parsed, set to failure code.
+     * @return an array of parsed arguments.  The caller owns both
+     * the array and its contents. Returns NULL if status is not U_ZERO_ERROR.
+     *
+     * @stable ICU 2.0
+     */
+    virtual Formattable* parse(const UnicodeString& source,
+                               int32_t& count,
+                               UErrorCode& status) const;
+
+    /**
+     * Parses the given string into an array of output arguments
+     * stored within a single Formattable of type kArray.
+     *
+     * @param source    The string to be parsed into an object.
+     * @param result    Formattable to be set to the parse result.
+     *                  If parse fails, return contents are undefined.
+     * @param pos       On input, starting position for parse. On output,
+     *                  final position after parse.  Unchanged if parse
+     *                  fails.
+     * @stable ICU 2.0
+     */
+    virtual void parseObject(const UnicodeString& source,
+                             Formattable& result,
+                             ParsePosition& pos) const;
+
+    /**
+     * Convert an 'apostrophe-friendly' pattern into a standard
+     * pattern.  Standard patterns treat all apostrophes as
+     * quotes, which is problematic in some languages, e.g.
+     * French, where apostrophe is commonly used.  This utility
+     * assumes that only an unpaired apostrophe immediately before
+     * a brace is a true quote.  Other unpaired apostrophes are paired,
+     * and the resulting standard pattern string is returned.
+     *
+     * <p><b>Note</b> it is not guaranteed that the returned pattern
+     * is indeed a valid pattern.  The only effect is to convert
+     * between patterns having different quoting semantics.
+     *
+     * @param pattern the 'apostrophe-friendly' patttern to convert
+     * @param status    Input/output error code.  If the pattern
+     *                  cannot be parsed, the failure code is set.
+     * @return the standard equivalent of the original pattern
+     * @stable ICU 3.4
+     */
+    static UnicodeString autoQuoteApostrophe(const UnicodeString& pattern,
+        UErrorCode& status);
+
+
+    /**
+     * Returns true if this MessageFormat uses named arguments,
+     * and false otherwise.  See class description.
+     *
+     * @return true if named arguments are used.
+     * @stable ICU 4.0
+     */
+    UBool usesNamedArguments() const;
+
+
+#ifndef U_HIDE_INTERNAL_API
+    /**
+     * This API is for ICU internal use only.
+     * Please do not use it.
+     *
+     * Returns argument types count in the parsed pattern.
+     * Used to distinguish pattern "{0} d" and "d".
+     *
+     * @return           The number of formattable types in the pattern
+     * @internal
+     */
+    int32_t getArgTypeCount() const;
+#endif  /* U_HIDE_INTERNAL_API */
+
+    /**
+     * Returns a unique class ID POLYMORPHICALLY.  Pure virtual override.
+     * This method is to implement a simple version of RTTI, since not all
+     * C++ compilers support genuine RTTI.  Polymorphic operator==() and
+     * clone() methods call this method.
+     *
+     * @return          The class ID for this object. All objects of a
+     *                  given class have the same class ID.  Objects of
+     *                  other classes have different class IDs.
+     * @stable ICU 2.0
+     */
+    virtual UClassID getDynamicClassID(void) const;
+
+    /**
+     * Return the class ID for this class.  This is useful only for
+     * comparing to a return value from getDynamicClassID().  For example:
+     * <pre>
+     * .   Base* polymorphic_pointer = createPolymorphicObject();
+     * .   if (polymorphic_pointer->getDynamicClassID() ==
+     * .      Derived::getStaticClassID()) ...
+     * </pre>
+     * @return          The class ID for all objects of this class.
+     * @stable ICU 2.0
+     */
+    static UClassID U_EXPORT2 getStaticClassID(void);
+
+#ifndef U_HIDE_INTERNAL_API
+    /**
+     * Compares two Format objects. This is used for constructing the hash
+     * tables.
+     *
+     * @param left pointer to a Format object. Must not be NULL.
+     * @param right pointer to a Format object. Must not be NULL.
+     *
+     * @return whether the two objects are the same
+     * @internal
+     */
+    static UBool equalFormats(const void* left, const void* right);
+#endif  /* U_HIDE_INTERNAL_API */
+
+private:
+
+    Locale              fLocale;
+    MessagePattern      msgPattern;
+    Format**            formatAliases; // see getFormats
+    int32_t             formatAliasesCapacity;
+
+    MessageFormat(); // default constructor not implemented
+
+     /**
+      * This provider helps defer instantiation of a PluralRules object
+      * until we actually need to select a keyword.
+      * For example, if the number matches an explicit-value selector like "=1"
+      * we do not need any PluralRules.
+      */
+    class U_I18N_API PluralSelectorProvider : public PluralFormat::PluralSelector {
+    public:
+        PluralSelectorProvider(const MessageFormat &mf, UPluralType type);
+        virtual ~PluralSelectorProvider();
+        virtual UnicodeString select(void *ctx, double number, UErrorCode& ec) const;
+
+        void reset();
+    private:
+        const MessageFormat &msgFormat;
+        PluralRules* rules;
+        UPluralType type;
+    };
+
+    /**
+     * A MessageFormat formats an array of arguments.  Each argument
+     * has an expected type, based on the pattern.  For example, if
+     * the pattern contains the subformat "{3,number,integer}", then
+     * we expect argument 3 to have type Formattable::kLong.  This
+     * array needs to grow dynamically if the MessageFormat is
+     * modified.
+     */
+    Formattable::Type* argTypes;
+    int32_t            argTypeCount;
+    int32_t            argTypeCapacity;
+
+    /**
+     * TRUE if there are different argTypes for the same argument.
+     * This only matters when the MessageFormat is used in the plain C (umsg_xxx) API
+     * where the pattern argTypes determine how the va_arg list is read.
+     */
+    UBool hasArgTypeConflicts;
+
+    // Variable-size array management
+    UBool allocateArgTypes(int32_t capacity, UErrorCode& status);
+
+    /**
+     * Default Format objects used when no format is specified and a
+     * numeric or date argument is formatted.  These are volatile
+     * cache objects maintained only for performance.  They do not
+     * participate in operator=(), copy constructor(), nor
+     * operator==().
+     */
+    NumberFormat* defaultNumberFormat;
+    DateFormat*   defaultDateFormat;
+
+    UHashtable* cachedFormatters;
+    UHashtable* customFormatArgStarts;
+
+    PluralSelectorProvider pluralProvider;
+    PluralSelectorProvider ordinalProvider;
+
+    /**
+     * Method to retrieve default formats (or NULL on failure).
+     * These are semantically const, but may modify *this.
+     */
+    const NumberFormat* getDefaultNumberFormat(UErrorCode&) const;
+    const DateFormat*   getDefaultDateFormat(UErrorCode&) const;
+
+    /**
+     * Finds the word s, in the keyword list and returns the located index.
+     * @param s the keyword to be searched for.
+     * @param list the list of keywords to be searched with.
+     * @return the index of the list which matches the keyword s.
+     */
+    static int32_t findKeyword( const UnicodeString& s,
+                                const char16_t * const *list);
+
+    /**
+     * Thin wrapper around the format(... AppendableWrapper ...) variant.
+     * Wraps the destination UnicodeString into an AppendableWrapper and
+     * supplies default values for some other parameters.
+     */
+    UnicodeString& format(const Formattable* arguments,
+                          const UnicodeString *argumentNames,
+                          int32_t cnt,
+                          UnicodeString& appendTo,
+                          FieldPosition* pos,
+                          UErrorCode& status) const;
+
+    /**
+     * Formats the arguments and writes the result into the
+     * AppendableWrapper, updates the field position.
+     *
+     * @param msgStart      Index to msgPattern part to start formatting from.
+     * @param plNumber      NULL except when formatting a plural argument sub-message
+     *                      where a '#' is replaced by the format string for this number.
+     * @param arguments     The formattable objects array. (Must not be NULL.)
+     * @param argumentNames NULL if numbered values are used. Otherwise the same
+     *                      length as "arguments", and each entry is the name of the
+     *                      corresponding argument in "arguments".
+     * @param cnt           The length of arguments (and of argumentNames if that is not NULL).
+     * @param appendTo      Output parameter to receive the result.
+     *                      The result string is appended to existing contents.
+     * @param pos           Field position status.
+     * @param success       The error code status.
+     */
+    void format(int32_t msgStart,
+                const void *plNumber,
+                const Formattable* arguments,
+                const UnicodeString *argumentNames,
+                int32_t cnt,
+                AppendableWrapper& appendTo,
+                FieldPosition* pos,
+                UErrorCode& success) const;
+
+    UnicodeString getArgName(int32_t partIndex);
+
+    void setArgStartFormat(int32_t argStart, Format* formatter, UErrorCode& status);
+
+    void setCustomArgStartFormat(int32_t argStart, Format* formatter, UErrorCode& status);
+
+    int32_t nextTopLevelArgStart(int32_t partIndex) const;
+
+    UBool argNameMatches(int32_t partIndex, const UnicodeString& argName, int32_t argNumber);
+
+    void cacheExplicitFormats(UErrorCode& status);
+
+    int32_t skipLeadingSpaces(UnicodeString& style);
+
+    Format* createAppropriateFormat(UnicodeString& type,
+                                    UnicodeString& style,
+                                    Formattable::Type& formattableType,
+                                    UParseError& parseError,
+                                    UErrorCode& ec);
+
+    const Formattable* getArgFromListByName(const Formattable* arguments,
+                                            const UnicodeString *argumentNames,
+                                            int32_t cnt, UnicodeString& name) const;
+
+    Formattable* parse(int32_t msgStart,
+                       const UnicodeString& source,
+                       ParsePosition& pos,
+                       int32_t& count,
+                       UErrorCode& ec) const;
+
+    FieldPosition* updateMetaData(AppendableWrapper& dest, int32_t prevLength,
+                                  FieldPosition* fp, const Formattable* argId) const;
+
+    /**
+     * Finds the "other" sub-message.
+     * @param partIndex the index of the first PluralFormat argument style part.
+     * @return the "other" sub-message start part index.
+     */
+    int32_t findOtherSubMessage(int32_t partIndex) const;
+
+    /**
+     * Returns the ARG_START index of the first occurrence of the plural number in a sub-message.
+     * Returns -1 if it is a REPLACE_NUMBER.
+     * Returns 0 if there is neither.
+     */
+    int32_t findFirstPluralNumberArg(int32_t msgStart, const UnicodeString &argName) const;
+
+    Format* getCachedFormatter(int32_t argumentNumber) const;
+
+    UnicodeString getLiteralStringUntilNextArgument(int32_t from) const;
+
+    void copyObjects(const MessageFormat& that, UErrorCode& ec);
+
+    void formatComplexSubMessage(int32_t msgStart,
+                                 const void *plNumber,
+                                 const Formattable* arguments,
+                                 const UnicodeString *argumentNames,
+                                 int32_t cnt,
+                                 AppendableWrapper& appendTo,
+                                 UErrorCode& success) const;
+
+    /**
+     * Convenience method that ought to be in NumberFormat
+     */
+    NumberFormat* createIntegerFormat(const Locale& locale, UErrorCode& status) const;
+
+    /**
+     * Returns array of argument types in the parsed pattern
+     * for use in C API.  Only for the use of umsg_vformat().  Not
+     * for public consumption.
+     * @param listCount  Output parameter to receive the size of array
+     * @return           The array of formattable types in the pattern
+     */
+    const Formattable::Type* getArgTypeList(int32_t& listCount) const {
+        listCount = argTypeCount;
+        return argTypes;
+    }
+
+    /**
+     * Resets the internal MessagePattern, and other associated caches.
+     */
+    void resetPattern();
+
+    /**
+     * A DummyFormatter that we use solely to store a NULL value. UHash does
+     * not support storing NULL values.
+     */
+    class U_I18N_API DummyFormat : public Format {
+    public:
+        virtual UBool operator==(const Format&) const;
+        virtual DummyFormat* clone() const;
+        virtual UnicodeString& format(const Formattable& obj,
+                              UnicodeString& appendTo,
+                              UErrorCode& status) const;
+        virtual UnicodeString& format(const Formattable&,
+                                      UnicodeString& appendTo,
+                                      FieldPosition&,
+                                      UErrorCode& status) const;
+        virtual UnicodeString& format(const Formattable& obj,
+                                      UnicodeString& appendTo,
+                                      FieldPositionIterator* posIter,
+                                      UErrorCode& status) const;
+        virtual void parseObject(const UnicodeString&,
+                                 Formattable&,
+                                 ParsePosition&) const;
+    };
+
+    friend class MessageFormatAdapter; // getFormatTypeList() access
+};
+
+U_NAMESPACE_END
+
+#endif /* #if !UCONFIG_NO_FORMATTING */
+
+#endif /* U_SHOW_CPLUSPLUS_API */
+
+#endif // _MSGFMT
+//eof