300 lines
9.9 KiB
C++
300 lines
9.9 KiB
C++
/*
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*******************************************************************************
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* Copyright (C) 2008-2010, International Business Machines Corporation and
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* others. All Rights Reserved.
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*******************************************************************************
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*
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*
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* File PLURRULE.H
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*
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* Modification History:*
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* Date Name Description
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*
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********************************************************************************
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*/
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#ifndef PLURRULE
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#define PLURRULE
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#include "unicode/utypes.h"
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/**
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* \file
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* \brief C++ API: PluralRules object
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*/
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#if !UCONFIG_NO_FORMATTING
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#include "unicode/format.h"
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U_NAMESPACE_BEGIN
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class Hashtable;
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class RuleChain;
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class RuleParser;
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/**
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* Defines rules for mapping positive long values onto a small set of
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* keywords. Rules are constructed from a text description, consisting
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* of a series of keywords and conditions. The {@link #select} method
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* examines each condition in order and returns the keyword for the
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* first condition that matches the number. If none match,
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* default rule(other) is returned.
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*
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* Examples:<pre>
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* "one: n is 1; few: n in 2..4"</pre>
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* This defines two rules, for 'one' and 'few'. The condition for
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* 'one' is "n is 1" which means that the number must be equal to
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* 1 for this condition to pass. The condition for 'few' is
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* "n in 2..4" which means that the number must be between 2 and
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* 4 inclusive for this condition to pass. All other numbers
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* are assigned the keyword "other" by the default rule.
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* </p><pre>
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* "zero: n is 0; one: n is 1; zero: n mod 100 in 1..19"</pre>
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* This illustrates that the same keyword can be defined multiple times.
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* Each rule is examined in order, and the first keyword whose condition
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* passes is the one returned. Also notes that a modulus is applied
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* to n in the last rule. Thus its condition holds for 119, 219, 319...
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* </p><pre>
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* "one: n is 1; few: n mod 10 in 2..4 and n mod 100 not in 12..14"</pre>
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* This illustrates conjunction and negation. The condition for 'few'
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* has two parts, both of which must be met: "n mod 10 in 2..4" and
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* "n mod 100 not in 12..14". The first part applies a modulus to n
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* before the test as in the previous example. The second part applies
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* a different modulus and also uses negation, thus it matches all
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* numbers _not_ in 12, 13, 14, 112, 113, 114, 212, 213, 214...
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* </p>
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* <p>
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* Syntax:<pre>
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* \code
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* rules = rule (';' rule)*
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* rule = keyword ':' condition
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* keyword = <identifier>
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* condition = and_condition ('or' and_condition)*
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* and_condition = relation ('and' relation)*
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* relation = is_relation | in_relation | within_relation | 'n' <EOL>
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* is_relation = expr 'is' ('not')? value
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* in_relation = expr ('not')? 'in' range
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* within_relation = expr ('not')? 'within' range
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* expr = 'n' ('mod' value)?
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* value = digit+
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* digit = 0|1|2|3|4|5|6|7|8|9
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* range = value'..'value
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* \endcode
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* </pre></p>
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* <p>
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* The difference between 'in' and 'within' is that 'in' only includes
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* integers in the specified range, while 'within' includes all values.</p>
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* <p>
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* Keywords
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* could be defined by users or from ICU locale data. There are 6
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* predefined values in ICU - 'zero', 'one', 'two', 'few', 'many' and
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* 'other'. Callers need to check the value of keyword returned by
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* {@link #select} method.
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* </p>
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*
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* Examples:<pre>
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* UnicodeString keyword = pl->select(number);
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* if (keyword== UnicodeString("one") {
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* ...
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* }
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* else if ( ... )
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* </pre>
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* <strong>Note:</strong><br>
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* <p>
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* ICU defines plural rules for many locales based on CLDR <i>Language Plural Rules</i>.
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* For these predefined rules, see CLDR page at
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* http://unicode.org/repos/cldr-tmp/trunk/diff/supplemental/language_plural_rules.html
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* </p>
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*/
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class U_I18N_API PluralRules : public UObject {
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public:
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/**
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* Constructor.
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* @param status Output param set to success/failure code on exit, which
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* must not indicate a failure before the function call.
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*
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* @stable ICU 4.0
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*/
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PluralRules(UErrorCode& status);
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/**
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* Copy constructor.
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* @stable ICU 4.0
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*/
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PluralRules(const PluralRules& other);
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/**
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* Destructor.
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* @stable ICU 4.0
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*/
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virtual ~PluralRules();
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/**
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* Clone
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* @stable ICU 4.0
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*/
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PluralRules* clone() const;
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/**
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* Assignment operator.
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* @stable ICU 4.0
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*/
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PluralRules& operator=(const PluralRules&);
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/**
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* Creates a PluralRules from a description if it is parsable, otherwise
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* returns null.
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*
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* @param description rule description
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* @param status Output param set to success/failure code on exit, which
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* must not indicate a failure before the function call.
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* @return new PluralRules pointer. NULL if there is an error.
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* @stable ICU 4.0
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*/
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static PluralRules* U_EXPORT2 createRules(const UnicodeString& description,
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UErrorCode& status);
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/**
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* The default rules that accept any number.
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*
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* @param status Output param set to success/failure code on exit, which
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* must not indicate a failure before the function call.
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* @return new PluralRules pointer. NULL if there is an error.
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* @stable ICU 4.0
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*/
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static PluralRules* U_EXPORT2 createDefaultRules(UErrorCode& status);
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/**
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* Provides access to the predefined <code>PluralRules</code> for a given
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* locale.
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*
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* @param locale The locale for which a <code>PluralRules</code> object is
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* returned.
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* @param status Output param set to success/failure code on exit, which
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* must not indicate a failure before the function call.
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* @return The predefined <code>PluralRules</code> object pointer for
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* this locale. If there's no predefined rules for this locale,
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* the rules for the closest parent in the locale hierarchy
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* that has one will be returned. The final fallback always
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* returns the default 'other' rules.
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* @stable ICU 4.0
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*/
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static PluralRules* U_EXPORT2 forLocale(const Locale& locale, UErrorCode& status);
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/**
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* Given a number, returns the keyword of the first rule that applies to
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* the number. This function can be used with isKeyword* functions to
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* determine the keyword for default plural rules.
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*
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* @param number The number for which the rule has to be determined.
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* @return The keyword of the selected rule.
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* @stable ICU 4.0
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*/
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UnicodeString select(int32_t number) const;
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/**
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* Given a number, returns the keyword of the first rule that applies to
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* the number. This function can be used with isKeyword* functions to
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* determine the keyword for default plural rules.
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*
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* @param number The number for which the rule has to be determined.
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* @return The keyword of the selected rule.
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* @stable ICU 4.0
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*/
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UnicodeString select(double number) const;
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/**
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* Returns a list of all rule keywords used in this <code>PluralRules</code>
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* object. The rule 'other' is always present by default.
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*
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* @param status Output param set to success/failure code on exit, which
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* must not indicate a failure before the function call.
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* @return StringEnumeration with the keywords.
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* The caller must delete the object.
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* @stable ICU 4.0
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*/
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StringEnumeration* getKeywords(UErrorCode& status) const;
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/**
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* Returns TRUE if the given keyword is defined in this
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* <code>PluralRules</code> object.
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*
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* @param keyword the input keyword.
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* @return TRUE if the input keyword is defined.
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* Otherwise, return FALSE.
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* @stable ICU 4.0
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*/
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UBool isKeyword(const UnicodeString& keyword) const;
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/**
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* Returns keyword for default plural form.
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*
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* @return keyword for default plural form.
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* @internal 4.0
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* @stable ICU 4.0
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*/
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UnicodeString getKeywordOther() const;
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/**
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* Compares the equality of two PluralRules objects.
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*
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* @param other The other PluralRules object to be compared with.
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* @return True if the given PluralRules is the same as this
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* PluralRules; false otherwise.
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* @stable ICU 4.0
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*/
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virtual UBool operator==(const PluralRules& other) const;
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/**
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* Compares the inequality of two PluralRules objects.
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*
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* @param other The PluralRules object to be compared with.
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* @return True if the given PluralRules is not the same as this
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* PluralRules; false otherwise.
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* @stable ICU 4.0
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*/
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UBool operator!=(const PluralRules& other) const {return !operator==(other);}
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/**
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* ICU "poor man's RTTI", returns a UClassID for this class.
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*
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* @stable ICU 4.0
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*
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*/
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static UClassID U_EXPORT2 getStaticClassID(void);
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/**
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* ICU "poor man's RTTI", returns a UClassID for the actual class.
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*
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* @stable ICU 4.0
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*/
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virtual UClassID getDynamicClassID() const;
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private:
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Hashtable *fLocaleStringsHash;
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UnicodeString mLocaleName;
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RuleChain *mRules;
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RuleParser *mParser;
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PluralRules(); // default constructor not implemented
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int32_t getRepeatLimit() const;
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void parseDescription(UnicodeString& ruleData, RuleChain& rules, UErrorCode &status);
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void getNextLocale(const UnicodeString& localeData, int32_t* curIndex, UnicodeString& localeName);
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void addRules(RuleChain& rules);
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int32_t getNumberValue(const UnicodeString& token) const;
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UnicodeString getRuleFromResource(const Locale& locale, UErrorCode& status);
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};
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U_NAMESPACE_END
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#endif /* #if !UCONFIG_NO_FORMATTING */
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#endif // _PLURRULE
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//eof
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