tor-browser

messagepattern.h (34600B)

---

// © 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:   UTF-8
*   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 U_SHOW_CPLUSPLUS_API

#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 nullptr.
    * @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 nullptr.
    * @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 nullptr.
    * @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 nullptr.
    * @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 nullptr.
    * @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
    */
   bool 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 bool 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 msgType=getType();
           if(msgType ==UMSGPAT_PART_TYPE_ARG_START || msgType ==UMSGPAT_PART_TYPE_ARG_LIMIT) {
               return static_cast<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
        */
       bool 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 bool 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;
       static const int32_t MAX_NESTED_LEVELS=0x03ff;

       // 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 /* U_SHOW_CPLUSPLUS_API */

#endif  // __MESSAGEPATTERN_H__