Add m-esr52 at 52.6.0

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diff --git a/intl/icu/source/common/unicode/messagepattern.h b/intl/icu/source/common/unicode/messagepattern.h
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+// Copyright (C) 2016 and later: Unicode, Inc. and others.
+// License & terms of use: http://www.unicode.org/copyright.html
+/*
+*******************************************************************************
+*   Copyright (C) 2011-2013, International Business Machines
+*   Corporation and others.  All Rights Reserved.
+*******************************************************************************
+*   file name:  messagepattern.h
+*   encoding:   US-ASCII
+*   tab size:   8 (not used)
+*   indentation:4
+*
+*   created on: 2011mar14
+*   created by: Markus W. Scherer
+*/
+
+#ifndef __MESSAGEPATTERN_H__
+#define __MESSAGEPATTERN_H__
+
+/**
+ * \file
+ * \brief C++ API: MessagePattern class: Parses and represents ICU MessageFormat patterns.
+ */
+
+#include "unicode/utypes.h"
+
+#if !UCONFIG_NO_FORMATTING
+
+#include "unicode/parseerr.h"
+#include "unicode/unistr.h"
+
+/**
+ * Mode for when an apostrophe starts quoted literal text for MessageFormat output.
+ * The default is DOUBLE_OPTIONAL unless overridden via uconfig.h
+ * (UCONFIG_MSGPAT_DEFAULT_APOSTROPHE_MODE).
+ * <p>
+ * A pair of adjacent apostrophes always results in a single apostrophe in the output,
+ * even when the pair is between two single, text-quoting apostrophes.
+ * <p>
+ * The following table shows examples of desired MessageFormat.format() output
+ * with the pattern strings that yield that output.
+ * <p>
+ * <table>
+ *   <tr>
+ *     <th>Desired output</th>
+ *     <th>DOUBLE_OPTIONAL</th>
+ *     <th>DOUBLE_REQUIRED</th>
+ *   </tr>
+ *   <tr>
+ *     <td>I see {many}</td>
+ *     <td>I see '{many}'</td>
+ *     <td>(same)</td>
+ *   </tr>
+ *   <tr>
+ *     <td>I said {'Wow!'}</td>
+ *     <td>I said '{''Wow!''}'</td>
+ *     <td>(same)</td>
+ *   </tr>
+ *   <tr>
+ *     <td>I don't know</td>
+ *     <td>I don't know OR<br> I don''t know</td>
+ *     <td>I don''t know</td>
+ *   </tr>
+ * </table>
+ * @stable ICU 4.8
+ * @see UCONFIG_MSGPAT_DEFAULT_APOSTROPHE_MODE
+ */
+enum UMessagePatternApostropheMode {
+    /**
+     * A literal apostrophe is represented by
+     * either a single or a double apostrophe pattern character.
+     * Within a MessageFormat pattern, a single apostrophe only starts quoted literal text
+     * if it immediately precedes a curly brace {},
+     * or a pipe symbol | if inside a choice format,
+     * or a pound symbol # if inside a plural format.
+     * <p>
+     * This is the default behavior starting with ICU 4.8.
+     * @stable ICU 4.8
+     */
+    UMSGPAT_APOS_DOUBLE_OPTIONAL,
+    /**
+     * A literal apostrophe must be represented by
+     * a double apostrophe pattern character.
+     * A single apostrophe always starts quoted literal text.
+     * <p>
+     * This is the behavior of ICU 4.6 and earlier, and of the JDK.
+     * @stable ICU 4.8
+     */
+    UMSGPAT_APOS_DOUBLE_REQUIRED
+};
+/**
+ * @stable ICU 4.8
+ */
+typedef enum UMessagePatternApostropheMode UMessagePatternApostropheMode;
+
+/**
+ * MessagePattern::Part type constants.
+ * @stable ICU 4.8
+ */
+enum UMessagePatternPartType {
+    /**
+     * Start of a message pattern (main or nested).
+     * The length is 0 for the top-level message
+     * and for a choice argument sub-message, otherwise 1 for the '{'.
+     * The value indicates the nesting level, starting with 0 for the main message.
+     * <p>
+     * There is always a later MSG_LIMIT part.
+     * @stable ICU 4.8
+     */
+    UMSGPAT_PART_TYPE_MSG_START,
+    /**
+     * End of a message pattern (main or nested).
+     * The length is 0 for the top-level message and
+     * the last sub-message of a choice argument,
+     * otherwise 1 for the '}' or (in a choice argument style) the '|'.
+     * The value indicates the nesting level, starting with 0 for the main message.
+     * @stable ICU 4.8
+     */
+    UMSGPAT_PART_TYPE_MSG_LIMIT,
+    /**
+     * Indicates a substring of the pattern string which is to be skipped when formatting.
+     * For example, an apostrophe that begins or ends quoted text
+     * would be indicated with such a part.
+     * The value is undefined and currently always 0.
+     * @stable ICU 4.8
+     */
+    UMSGPAT_PART_TYPE_SKIP_SYNTAX,
+    /**
+     * Indicates that a syntax character needs to be inserted for auto-quoting.
+     * The length is 0.
+     * The value is the character code of the insertion character. (U+0027=APOSTROPHE)
+     * @stable ICU 4.8
+     */
+    UMSGPAT_PART_TYPE_INSERT_CHAR,
+    /**
+     * Indicates a syntactic (non-escaped) # symbol in a plural variant.
+     * When formatting, replace this part's substring with the
+     * (value-offset) for the plural argument value.
+     * The value is undefined and currently always 0.
+     * @stable ICU 4.8
+     */
+    UMSGPAT_PART_TYPE_REPLACE_NUMBER,
+    /**
+     * Start of an argument.
+     * The length is 1 for the '{'.
+     * The value is the ordinal value of the ArgType. Use getArgType().
+     * <p>
+     * This part is followed by either an ARG_NUMBER or ARG_NAME,
+     * followed by optional argument sub-parts (see UMessagePatternArgType constants)
+     * and finally an ARG_LIMIT part.
+     * @stable ICU 4.8
+     */
+    UMSGPAT_PART_TYPE_ARG_START,
+    /**
+     * End of an argument.
+     * The length is 1 for the '}'.
+     * The value is the ordinal value of the ArgType. Use getArgType().
+     * @stable ICU 4.8
+     */
+    UMSGPAT_PART_TYPE_ARG_LIMIT,
+    /**
+     * The argument number, provided by the value.
+     * @stable ICU 4.8
+     */
+    UMSGPAT_PART_TYPE_ARG_NUMBER,
+    /**
+     * The argument name.
+     * The value is undefined and currently always 0.
+     * @stable ICU 4.8
+     */
+    UMSGPAT_PART_TYPE_ARG_NAME,
+    /**
+     * The argument type.
+     * The value is undefined and currently always 0.
+     * @stable ICU 4.8
+     */
+    UMSGPAT_PART_TYPE_ARG_TYPE,
+    /**
+     * The argument style text.
+     * The value is undefined and currently always 0.
+     * @stable ICU 4.8
+     */
+    UMSGPAT_PART_TYPE_ARG_STYLE,
+    /**
+     * A selector substring in a "complex" argument style.
+     * The value is undefined and currently always 0.
+     * @stable ICU 4.8
+     */
+    UMSGPAT_PART_TYPE_ARG_SELECTOR,
+    /**
+     * An integer value, for example the offset or an explicit selector value
+     * in a PluralFormat style.
+     * The part value is the integer value.
+     * @stable ICU 4.8
+     */
+    UMSGPAT_PART_TYPE_ARG_INT,
+    /**
+     * A numeric value, for example the offset or an explicit selector value
+     * in a PluralFormat style.
+     * The part value is an index into an internal array of numeric values;
+     * use getNumericValue().
+     * @stable ICU 4.8
+     */
+    UMSGPAT_PART_TYPE_ARG_DOUBLE
+};
+/**
+ * @stable ICU 4.8
+ */
+typedef enum UMessagePatternPartType UMessagePatternPartType;
+
+/**
+ * Argument type constants.
+ * Returned by Part.getArgType() for ARG_START and ARG_LIMIT parts.
+ *
+ * Messages nested inside an argument are each delimited by MSG_START and MSG_LIMIT,
+ * with a nesting level one greater than the surrounding message.
+ * @stable ICU 4.8
+ */
+enum UMessagePatternArgType {
+    /**
+     * The argument has no specified type.
+     * @stable ICU 4.8
+     */
+    UMSGPAT_ARG_TYPE_NONE,
+    /**
+     * The argument has a "simple" type which is provided by the ARG_TYPE part.
+     * An ARG_STYLE part might follow that.
+     * @stable ICU 4.8
+     */
+    UMSGPAT_ARG_TYPE_SIMPLE,
+    /**
+     * The argument is a ChoiceFormat with one or more
+     * ((ARG_INT | ARG_DOUBLE), ARG_SELECTOR, message) tuples.
+     * @stable ICU 4.8
+     */
+    UMSGPAT_ARG_TYPE_CHOICE,
+    /**
+     * The argument is a cardinal-number PluralFormat with an optional ARG_INT or ARG_DOUBLE offset
+     * (e.g., offset:1)
+     * and one or more (ARG_SELECTOR [explicit-value] message) tuples.
+     * If the selector has an explicit value (e.g., =2), then
+     * that value is provided by the ARG_INT or ARG_DOUBLE part preceding the message.
+     * Otherwise the message immediately follows the ARG_SELECTOR.
+     * @stable ICU 4.8
+     */
+    UMSGPAT_ARG_TYPE_PLURAL,
+    /**
+     * The argument is a SelectFormat with one or more (ARG_SELECTOR, message) pairs.
+     * @stable ICU 4.8
+     */
+    UMSGPAT_ARG_TYPE_SELECT,
+    /**
+     * The argument is an ordinal-number PluralFormat
+     * with the same style parts sequence and semantics as UMSGPAT_ARG_TYPE_PLURAL.
+     * @stable ICU 50
+     */
+    UMSGPAT_ARG_TYPE_SELECTORDINAL
+};
+/**
+ * @stable ICU 4.8
+ */
+typedef enum UMessagePatternArgType UMessagePatternArgType;
+
+/**
+ * \def UMSGPAT_ARG_TYPE_HAS_PLURAL_STYLE
+ * Returns TRUE if the argument type has a plural style part sequence and semantics,
+ * for example UMSGPAT_ARG_TYPE_PLURAL and UMSGPAT_ARG_TYPE_SELECTORDINAL.
+ * @stable ICU 50
+ */
+#define UMSGPAT_ARG_TYPE_HAS_PLURAL_STYLE(argType) \
+    ((argType)==UMSGPAT_ARG_TYPE_PLURAL || (argType)==UMSGPAT_ARG_TYPE_SELECTORDINAL)
+
+enum {
+    /**
+     * Return value from MessagePattern.validateArgumentName() for when
+     * the string is a valid "pattern identifier" but not a number.
+     * @stable ICU 4.8
+     */
+    UMSGPAT_ARG_NAME_NOT_NUMBER=-1,
+
+    /**
+     * Return value from MessagePattern.validateArgumentName() for when
+     * the string is invalid.
+     * It might not be a valid "pattern identifier",
+     * or it have only ASCII digits but there is a leading zero or the number is too large.
+     * @stable ICU 4.8
+     */
+    UMSGPAT_ARG_NAME_NOT_VALID=-2
+};
+
+/**
+ * Special value that is returned by getNumericValue(Part) when no
+ * numeric value is defined for a part.
+ * @see MessagePattern.getNumericValue()
+ * @stable ICU 4.8
+ */
+#define UMSGPAT_NO_NUMERIC_VALUE ((double)(-123456789))
+
+U_NAMESPACE_BEGIN
+
+class MessagePatternDoubleList;
+class MessagePatternPartsList;
+
+/**
+ * Parses and represents ICU MessageFormat patterns.
+ * Also handles patterns for ChoiceFormat, PluralFormat and SelectFormat.
+ * Used in the implementations of those classes as well as in tools
+ * for message validation, translation and format conversion.
+ * <p>
+ * The parser handles all syntax relevant for identifying message arguments.
+ * This includes "complex" arguments whose style strings contain
+ * nested MessageFormat pattern substrings.
+ * For "simple" arguments (with no nested MessageFormat pattern substrings),
+ * the argument style is not parsed any further.
+ * <p>
+ * The parser handles named and numbered message arguments and allows both in one message.
+ * <p>
+ * Once a pattern has been parsed successfully, iterate through the parsed data
+ * with countParts(), getPart() and related methods.
+ * <p>
+ * The data logically represents a parse tree, but is stored and accessed
+ * as a list of "parts" for fast and simple parsing and to minimize object allocations.
+ * Arguments and nested messages are best handled via recursion.
+ * For every _START "part", MessagePattern.getLimitPartIndex() efficiently returns
+ * the index of the corresponding _LIMIT "part".
+ * <p>
+ * List of "parts":
+ * <pre>
+ * message = MSG_START (SKIP_SYNTAX | INSERT_CHAR | REPLACE_NUMBER | argument)* MSG_LIMIT
+ * argument = noneArg | simpleArg | complexArg
+ * complexArg = choiceArg | pluralArg | selectArg
+ *
+ * noneArg = ARG_START.NONE (ARG_NAME | ARG_NUMBER) ARG_LIMIT.NONE
+ * simpleArg = ARG_START.SIMPLE (ARG_NAME | ARG_NUMBER) ARG_TYPE [ARG_STYLE] ARG_LIMIT.SIMPLE
+ * choiceArg = ARG_START.CHOICE (ARG_NAME | ARG_NUMBER) choiceStyle ARG_LIMIT.CHOICE
+ * pluralArg = ARG_START.PLURAL (ARG_NAME | ARG_NUMBER) pluralStyle ARG_LIMIT.PLURAL
+ * selectArg = ARG_START.SELECT (ARG_NAME | ARG_NUMBER) selectStyle ARG_LIMIT.SELECT
+ *
+ * choiceStyle = ((ARG_INT | ARG_DOUBLE) ARG_SELECTOR message)+
+ * pluralStyle = [ARG_INT | ARG_DOUBLE] (ARG_SELECTOR [ARG_INT | ARG_DOUBLE] message)+
+ * selectStyle = (ARG_SELECTOR message)+
+ * </pre>
+ * <ul>
+ *   <li>Literal output text is not represented directly by "parts" but accessed
+ *       between parts of a message, from one part's getLimit() to the next part's getIndex().
+ *   <li><code>ARG_START.CHOICE</code> stands for an ARG_START Part with ArgType CHOICE.
+ *   <li>In the choiceStyle, the ARG_SELECTOR has the '<', the '#' or
+ *       the less-than-or-equal-to sign (U+2264).
+ *   <li>In the pluralStyle, the first, optional numeric Part has the "offset:" value.
+ *       The optional numeric Part between each (ARG_SELECTOR, message) pair
+ *       is the value of an explicit-number selector like "=2",
+ *       otherwise the selector is a non-numeric identifier.
+ *   <li>The REPLACE_NUMBER Part can occur only in an immediate sub-message of the pluralStyle.
+ * </ul>
+ * <p>
+ * This class is not intended for public subclassing.
+ *
+ * @stable ICU 4.8
+ */
+class U_COMMON_API MessagePattern : public UObject {
+public:
+    /**
+     * Constructs an empty MessagePattern with default UMessagePatternApostropheMode.
+     * @param errorCode Standard ICU error code. Its input value must
+     *                  pass the U_SUCCESS() test, or else the function returns
+     *                  immediately. Check for U_FAILURE() on output or use with
+     *                  function chaining. (See User Guide for details.)
+     * @stable ICU 4.8
+     */
+    MessagePattern(UErrorCode &errorCode);
+
+    /**
+     * Constructs an empty MessagePattern.
+     * @param mode Explicit UMessagePatternApostropheMode.
+     * @param errorCode Standard ICU error code. Its input value must
+     *                  pass the U_SUCCESS() test, or else the function returns
+     *                  immediately. Check for U_FAILURE() on output or use with
+     *                  function chaining. (See User Guide for details.)
+     * @stable ICU 4.8
+     */
+    MessagePattern(UMessagePatternApostropheMode mode, UErrorCode &errorCode);
+
+    /**
+     * Constructs a MessagePattern with default UMessagePatternApostropheMode and
+     * parses the MessageFormat pattern string.
+     * @param pattern a MessageFormat pattern string
+     * @param parseError Struct to receive information on the position
+     *                   of an error within the pattern.
+     *                   Can be NULL.
+     * @param errorCode Standard ICU error code. Its input value must
+     *                  pass the U_SUCCESS() test, or else the function returns
+     *                  immediately. Check for U_FAILURE() on output or use with
+     *                  function chaining. (See User Guide for details.)
+     * TODO: turn @throws into UErrorCode specifics?
+     * @throws IllegalArgumentException for syntax errors in the pattern string
+     * @throws IndexOutOfBoundsException if certain limits are exceeded
+     *         (e.g., argument number too high, argument name too long, etc.)
+     * @throws NumberFormatException if a number could not be parsed
+     * @stable ICU 4.8
+     */
+    MessagePattern(const UnicodeString &pattern, UParseError *parseError, UErrorCode &errorCode);
+
+    /**
+     * Copy constructor.
+     * @param other Object to copy.
+     * @stable ICU 4.8
+     */
+    MessagePattern(const MessagePattern &other);
+
+    /**
+     * Assignment operator.
+     * @param other Object to copy.
+     * @return *this=other
+     * @stable ICU 4.8
+     */
+    MessagePattern &operator=(const MessagePattern &other);
+
+    /**
+     * Destructor.
+     * @stable ICU 4.8
+     */
+    virtual ~MessagePattern();
+
+    /**
+     * Parses a MessageFormat pattern string.
+     * @param pattern a MessageFormat pattern string
+     * @param parseError Struct to receive information on the position
+     *                   of an error within the pattern.
+     *                   Can be NULL.
+     * @param errorCode Standard ICU error code. Its input value must
+     *                  pass the U_SUCCESS() test, or else the function returns
+     *                  immediately. Check for U_FAILURE() on output or use with
+     *                  function chaining. (See User Guide for details.)
+     * @return *this
+     * @throws IllegalArgumentException for syntax errors in the pattern string
+     * @throws IndexOutOfBoundsException if certain limits are exceeded
+     *         (e.g., argument number too high, argument name too long, etc.)
+     * @throws NumberFormatException if a number could not be parsed
+     * @stable ICU 4.8
+     */
+    MessagePattern &parse(const UnicodeString &pattern,
+                          UParseError *parseError, UErrorCode &errorCode);
+
+    /**
+     * Parses a ChoiceFormat pattern string.
+     * @param pattern a ChoiceFormat pattern string
+     * @param parseError Struct to receive information on the position
+     *                   of an error within the pattern.
+     *                   Can be NULL.
+     * @param errorCode Standard ICU error code. Its input value must
+     *                  pass the U_SUCCESS() test, or else the function returns
+     *                  immediately. Check for U_FAILURE() on output or use with
+     *                  function chaining. (See User Guide for details.)
+     * @return *this
+     * @throws IllegalArgumentException for syntax errors in the pattern string
+     * @throws IndexOutOfBoundsException if certain limits are exceeded
+     *         (e.g., argument number too high, argument name too long, etc.)
+     * @throws NumberFormatException if a number could not be parsed
+     * @stable ICU 4.8
+     */
+    MessagePattern &parseChoiceStyle(const UnicodeString &pattern,
+                                     UParseError *parseError, UErrorCode &errorCode);
+
+    /**
+     * Parses a PluralFormat pattern string.
+     * @param pattern a PluralFormat pattern string
+     * @param parseError Struct to receive information on the position
+     *                   of an error within the pattern.
+     *                   Can be NULL.
+     * @param errorCode Standard ICU error code. Its input value must
+     *                  pass the U_SUCCESS() test, or else the function returns
+     *                  immediately. Check for U_FAILURE() on output or use with
+     *                  function chaining. (See User Guide for details.)
+     * @return *this
+     * @throws IllegalArgumentException for syntax errors in the pattern string
+     * @throws IndexOutOfBoundsException if certain limits are exceeded
+     *         (e.g., argument number too high, argument name too long, etc.)
+     * @throws NumberFormatException if a number could not be parsed
+     * @stable ICU 4.8
+     */
+    MessagePattern &parsePluralStyle(const UnicodeString &pattern,
+                                     UParseError *parseError, UErrorCode &errorCode);
+
+    /**
+     * Parses a SelectFormat pattern string.
+     * @param pattern a SelectFormat pattern string
+     * @param parseError Struct to receive information on the position
+     *                   of an error within the pattern.
+     *                   Can be NULL.
+     * @param errorCode Standard ICU error code. Its input value must
+     *                  pass the U_SUCCESS() test, or else the function returns
+     *                  immediately. Check for U_FAILURE() on output or use with
+     *                  function chaining. (See User Guide for details.)
+     * @return *this
+     * @throws IllegalArgumentException for syntax errors in the pattern string
+     * @throws IndexOutOfBoundsException if certain limits are exceeded
+     *         (e.g., argument number too high, argument name too long, etc.)
+     * @throws NumberFormatException if a number could not be parsed
+     * @stable ICU 4.8
+     */
+    MessagePattern &parseSelectStyle(const UnicodeString &pattern,
+                                     UParseError *parseError, UErrorCode &errorCode);
+
+    /**
+     * Clears this MessagePattern.
+     * countParts() will return 0.
+     * @stable ICU 4.8
+     */
+    void clear();
+
+    /**
+     * Clears this MessagePattern and sets the UMessagePatternApostropheMode.
+     * countParts() will return 0.
+     * @param mode The new UMessagePatternApostropheMode.
+     * @stable ICU 4.8
+     */
+    void clearPatternAndSetApostropheMode(UMessagePatternApostropheMode mode) {
+        clear();
+        aposMode=mode;
+    }
+
+    /**
+     * @param other another object to compare with.
+     * @return TRUE if this object is equivalent to the other one.
+     * @stable ICU 4.8
+     */
+    UBool operator==(const MessagePattern &other) const;
+
+    /**
+     * @param other another object to compare with.
+     * @return FALSE if this object is equivalent to the other one.
+     * @stable ICU 4.8
+     */
+    inline UBool operator!=(const MessagePattern &other) const {
+        return !operator==(other);
+    }
+
+    /**
+     * @return A hash code for this object.
+     * @stable ICU 4.8
+     */
+    int32_t hashCode() const;
+
+    /**
+     * @return this instance's UMessagePatternApostropheMode.
+     * @stable ICU 4.8
+     */
+    UMessagePatternApostropheMode getApostropheMode() const {
+        return aposMode;
+    }
+
+    // Java has package-private jdkAposMode() here.
+    // In C++, this is declared in the MessageImpl class.
+
+    /**
+     * @return the parsed pattern string (null if none was parsed).
+     * @stable ICU 4.8
+     */
+    const UnicodeString &getPatternString() const {
+        return msg;
+    }
+
+    /**
+     * Does the parsed pattern have named arguments like {first_name}?
+     * @return TRUE if the parsed pattern has at least one named argument.
+     * @stable ICU 4.8
+     */
+    UBool hasNamedArguments() const {
+        return hasArgNames;
+    }
+
+    /**
+     * Does the parsed pattern have numbered arguments like {2}?
+     * @return TRUE if the parsed pattern has at least one numbered argument.
+     * @stable ICU 4.8
+     */
+    UBool hasNumberedArguments() const {
+        return hasArgNumbers;
+    }
+
+    /**
+     * Validates and parses an argument name or argument number string.
+     * An argument name must be a "pattern identifier", that is, it must contain
+     * no Unicode Pattern_Syntax or Pattern_White_Space characters.
+     * If it only contains ASCII digits, then it must be a small integer with no leading zero.
+     * @param name Input string.
+     * @return &gt;=0 if the name is a valid number,
+     *         ARG_NAME_NOT_NUMBER (-1) if it is a "pattern identifier" but not all ASCII digits,
+     *         ARG_NAME_NOT_VALID (-2) if it is neither.
+     * @stable ICU 4.8
+     */
+    static int32_t validateArgumentName(const UnicodeString &name);
+
+    /**
+     * Returns a version of the parsed pattern string where each ASCII apostrophe
+     * is doubled (escaped) if it is not already, and if it is not interpreted as quoting syntax.
+     * <p>
+     * For example, this turns "I don't '{know}' {gender,select,female{h''er}other{h'im}}."
+     * into "I don''t '{know}' {gender,select,female{h''er}other{h''im}}."
+     * @return the deep-auto-quoted version of the parsed pattern string.
+     * @see MessageFormat.autoQuoteApostrophe()
+     * @stable ICU 4.8
+     */
+    UnicodeString autoQuoteApostropheDeep() const;
+
+    class Part;
+
+    /**
+     * Returns the number of "parts" created by parsing the pattern string.
+     * Returns 0 if no pattern has been parsed or clear() was called.
+     * @return the number of pattern parts.
+     * @stable ICU 4.8
+     */
+    int32_t countParts() const {
+        return partsLength;
+    }
+
+    /**
+     * Gets the i-th pattern "part".
+     * @param i The index of the Part data. (0..countParts()-1)
+     * @return the i-th pattern "part".
+     * @stable ICU 4.8
+     */
+    const Part &getPart(int32_t i) const {
+        return parts[i];
+    }
+
+    /**
+     * Returns the UMessagePatternPartType of the i-th pattern "part".
+     * Convenience method for getPart(i).getType().
+     * @param i The index of the Part data. (0..countParts()-1)
+     * @return The UMessagePatternPartType of the i-th Part.
+     * @stable ICU 4.8
+     */
+    UMessagePatternPartType getPartType(int32_t i) const {
+        return getPart(i).type;
+    }
+
+    /**
+     * Returns the pattern index of the specified pattern "part".
+     * Convenience method for getPart(partIndex).getIndex().
+     * @param partIndex The index of the Part data. (0..countParts()-1)
+     * @return The pattern index of this Part.
+     * @stable ICU 4.8
+     */
+    int32_t getPatternIndex(int32_t partIndex) const {
+        return getPart(partIndex).index;
+    }
+
+    /**
+     * Returns the substring of the pattern string indicated by the Part.
+     * Convenience method for getPatternString().substring(part.getIndex(), part.getLimit()).
+     * @param part a part of this MessagePattern.
+     * @return the substring associated with part.
+     * @stable ICU 4.8
+     */
+    UnicodeString getSubstring(const Part &part) const {
+        return msg.tempSubString(part.index, part.length);
+    }
+
+    /**
+     * Compares the part's substring with the input string s.
+     * @param part a part of this MessagePattern.
+     * @param s a string.
+     * @return TRUE if getSubstring(part).equals(s).
+     * @stable ICU 4.8
+     */
+    UBool partSubstringMatches(const Part &part, const UnicodeString &s) const {
+        return 0==msg.compare(part.index, part.length, s);
+    }
+
+    /**
+     * Returns the numeric value associated with an ARG_INT or ARG_DOUBLE.
+     * @param part a part of this MessagePattern.
+     * @return the part's numeric value, or UMSGPAT_NO_NUMERIC_VALUE if this is not a numeric part.
+     * @stable ICU 4.8
+     */
+    double getNumericValue(const Part &part) const;
+
+    /**
+     * Returns the "offset:" value of a PluralFormat argument, or 0 if none is specified.
+     * @param pluralStart the index of the first PluralFormat argument style part. (0..countParts()-1)
+     * @return the "offset:" value.
+     * @stable ICU 4.8
+     */
+    double getPluralOffset(int32_t pluralStart) const;
+
+    /**
+     * Returns the index of the ARG|MSG_LIMIT part corresponding to the ARG|MSG_START at start.
+     * @param start The index of some Part data (0..countParts()-1);
+     *        this Part should be of Type ARG_START or MSG_START.
+     * @return The first i>start where getPart(i).getType()==ARG|MSG_LIMIT at the same nesting level,
+     *         or start itself if getPartType(msgStart)!=ARG|MSG_START.
+     * @stable ICU 4.8
+     */
+    int32_t getLimitPartIndex(int32_t start) const {
+        int32_t limit=getPart(start).limitPartIndex;
+        if(limit<start) {
+            return start;
+        }
+        return limit;
+    }
+
+    /**
+     * A message pattern "part", representing a pattern parsing event.
+     * There is a part for the start and end of a message or argument,
+     * for quoting and escaping of and with ASCII apostrophes,
+     * and for syntax elements of "complex" arguments.
+     * @stable ICU 4.8
+     */
+    class Part : public UMemory {
+    public:
+        /**
+         * Default constructor, do not use.
+         * @internal
+         */
+        Part() {}
+
+        /**
+         * Returns the type of this part.
+         * @return the part type.
+         * @stable ICU 4.8
+         */
+        UMessagePatternPartType getType() const {
+            return type;
+        }
+
+        /**
+         * Returns the pattern string index associated with this Part.
+         * @return this part's pattern string index.
+         * @stable ICU 4.8
+         */
+        int32_t getIndex() const {
+            return index;
+        }
+
+        /**
+         * Returns the length of the pattern substring associated with this Part.
+         * This is 0 for some parts.
+         * @return this part's pattern substring length.
+         * @stable ICU 4.8
+         */
+        int32_t getLength() const {
+            return length;
+        }
+
+        /**
+         * Returns the pattern string limit (exclusive-end) index associated with this Part.
+         * Convenience method for getIndex()+getLength().
+         * @return this part's pattern string limit index, same as getIndex()+getLength().
+         * @stable ICU 4.8
+         */
+        int32_t getLimit() const {
+            return index+length;
+        }
+
+        /**
+         * Returns a value associated with this part.
+         * See the documentation of each part type for details.
+         * @return the part value.
+         * @stable ICU 4.8
+         */
+        int32_t getValue() const {
+            return value;
+        }
+
+        /**
+         * Returns the argument type if this part is of type ARG_START or ARG_LIMIT,
+         * otherwise UMSGPAT_ARG_TYPE_NONE.
+         * @return the argument type for this part.
+         * @stable ICU 4.8
+         */
+        UMessagePatternArgType getArgType() const {
+            UMessagePatternPartType type=getType();
+            if(type==UMSGPAT_PART_TYPE_ARG_START || type==UMSGPAT_PART_TYPE_ARG_LIMIT) {
+                return (UMessagePatternArgType)value;
+            } else {
+                return UMSGPAT_ARG_TYPE_NONE;
+            }
+        }
+
+        /**
+         * Indicates whether the Part type has a numeric value.
+         * If so, then that numeric value can be retrieved via MessagePattern.getNumericValue().
+         * @param type The Part type to be tested.
+         * @return TRUE if the Part type has a numeric value.
+         * @stable ICU 4.8
+         */
+        static UBool hasNumericValue(UMessagePatternPartType type) {
+            return type==UMSGPAT_PART_TYPE_ARG_INT || type==UMSGPAT_PART_TYPE_ARG_DOUBLE;
+        }
+
+        /**
+         * @param other another object to compare with.
+         * @return TRUE if this object is equivalent to the other one.
+         * @stable ICU 4.8
+         */
+        UBool operator==(const Part &other) const;
+
+        /**
+         * @param other another object to compare with.
+         * @return FALSE if this object is equivalent to the other one.
+         * @stable ICU 4.8
+         */
+        inline UBool operator!=(const Part &other) const {
+            return !operator==(other);
+        }
+
+        /**
+         * @return A hash code for this object.
+         * @stable ICU 4.8
+         */
+        int32_t hashCode() const {
+            return ((type*37+index)*37+length)*37+value;
+        }
+
+    private:
+        friend class MessagePattern;
+
+        static const int32_t MAX_LENGTH=0xffff;
+        static const int32_t MAX_VALUE=0x7fff;
+
+        // Some fields are not final because they are modified during pattern parsing.
+        // After pattern parsing, the parts are effectively immutable.
+        UMessagePatternPartType type;
+        int32_t index;
+        uint16_t length;
+        int16_t value;
+        int32_t limitPartIndex;
+    };
+
+private:
+    void preParse(const UnicodeString &pattern, UParseError *parseError, UErrorCode &errorCode);
+
+    void postParse();
+
+    int32_t parseMessage(int32_t index, int32_t msgStartLength,
+                         int32_t nestingLevel, UMessagePatternArgType parentType,
+                         UParseError *parseError, UErrorCode &errorCode);
+
+    int32_t parseArg(int32_t index, int32_t argStartLength, int32_t nestingLevel,
+                     UParseError *parseError, UErrorCode &errorCode);
+
+    int32_t parseSimpleStyle(int32_t index, UParseError *parseError, UErrorCode &errorCode);
+
+    int32_t parseChoiceStyle(int32_t index, int32_t nestingLevel,
+                             UParseError *parseError, UErrorCode &errorCode);
+
+    int32_t parsePluralOrSelectStyle(UMessagePatternArgType argType, int32_t index, int32_t nestingLevel,
+                                     UParseError *parseError, UErrorCode &errorCode);
+
+    /**
+     * Validates and parses an argument name or argument number string.
+     * This internal method assumes that the input substring is a "pattern identifier".
+     * @return &gt;=0 if the name is a valid number,
+     *         ARG_NAME_NOT_NUMBER (-1) if it is a "pattern identifier" but not all ASCII digits,
+     *         ARG_NAME_NOT_VALID (-2) if it is neither.
+     * @see #validateArgumentName(String)
+     */
+    static int32_t parseArgNumber(const UnicodeString &s, int32_t start, int32_t limit);
+
+    int32_t parseArgNumber(int32_t start, int32_t limit) {
+        return parseArgNumber(msg, start, limit);
+    }
+
+    /**
+     * Parses a number from the specified message substring.
+     * @param start start index into the message string
+     * @param limit limit index into the message string, must be start<limit
+     * @param allowInfinity TRUE if U+221E is allowed (for ChoiceFormat)
+     * @param parseError
+     * @param errorCode
+     */
+    void parseDouble(int32_t start, int32_t limit, UBool allowInfinity,
+                     UParseError *parseError, UErrorCode &errorCode);
+
+    // Java has package-private appendReducedApostrophes() here.
+    // In C++, this is declared in the MessageImpl class.
+
+    int32_t skipWhiteSpace(int32_t index);
+
+    int32_t skipIdentifier(int32_t index);
+
+    /**
+     * Skips a sequence of characters that could occur in a double value.
+     * Does not fully parse or validate the value.
+     */
+    int32_t skipDouble(int32_t index);
+
+    static UBool isArgTypeChar(UChar32 c);
+
+    UBool isChoice(int32_t index);
+
+    UBool isPlural(int32_t index);
+
+    UBool isSelect(int32_t index);
+
+    UBool isOrdinal(int32_t index);
+
+    /**
+     * @return TRUE if we are inside a MessageFormat (sub-)pattern,
+     *         as opposed to inside a top-level choice/plural/select pattern.
+     */
+    UBool inMessageFormatPattern(int32_t nestingLevel);
+
+    /**
+     * @return TRUE if we are in a MessageFormat sub-pattern
+     *         of a top-level ChoiceFormat pattern.
+     */
+    UBool inTopLevelChoiceMessage(int32_t nestingLevel, UMessagePatternArgType parentType);
+
+    void addPart(UMessagePatternPartType type, int32_t index, int32_t length,
+                 int32_t value, UErrorCode &errorCode);
+
+    void addLimitPart(int32_t start,
+                      UMessagePatternPartType type, int32_t index, int32_t length,
+                      int32_t value, UErrorCode &errorCode);
+
+    void addArgDoublePart(double numericValue, int32_t start, int32_t length, UErrorCode &errorCode);
+
+    void setParseError(UParseError *parseError, int32_t index);
+
+    UBool init(UErrorCode &errorCode);
+    UBool copyStorage(const MessagePattern &other, UErrorCode &errorCode);
+
+    UMessagePatternApostropheMode aposMode;
+    UnicodeString msg;
+    // ArrayList<Part> parts=new ArrayList<Part>();
+    MessagePatternPartsList *partsList;
+    Part *parts;
+    int32_t partsLength;
+    // ArrayList<Double> numericValues;
+    MessagePatternDoubleList *numericValuesList;
+    double *numericValues;
+    int32_t numericValuesLength;
+    UBool hasArgNames;
+    UBool hasArgNumbers;
+    UBool needsAutoQuoting;
+};
+
+U_NAMESPACE_END
+
+#endif  // !UCONFIG_NO_FORMATTING
+
+#endif  // __MESSAGEPATTERN_H__