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+// © 2016 and later: Unicode, Inc. and others.
+// License & terms of use: http://www.unicode.org/copyright.html
+/*
+*******************************************************************************
+* Copyright (C) 2007-2014, International Business Machines Corporation and
+* others. All Rights Reserved.
+*******************************************************************************
+*
+
+* File PLURFMT.H
+********************************************************************************
+*/
+
+#ifndef PLURFMT
+#define PLURFMT
+
+#include "unicode/utypes.h"
+
+#if U_SHOW_CPLUSPLUS_API
+
+/**
+ * \file
+ * \brief C++ API: PluralFormat object
+ */
+
+#if !UCONFIG_NO_FORMATTING
+
+#include "unicode/messagepattern.h"
+#include "unicode/numfmt.h"
+#include "unicode/plurrule.h"
+
+U_NAMESPACE_BEGIN
+
+class Hashtable;
+class NFRule;
+
+/**
+ * <p>
+ * <code>PluralFormat</code> supports the creation of internationalized
+ * messages with plural inflection. It is based on <i>plural
+ * selection</i>, i.e. the caller specifies messages for each
+ * plural case that can appear in the user's language and the
+ * <code>PluralFormat</code> selects the appropriate message based on
+ * the number.
+ * </p>
+ * <h4>The Problem of Plural Forms in Internationalized Messages</h4>
+ * <p>
+ * Different languages have different ways to inflect
+ * plurals. Creating internationalized messages that include plural
+ * forms is only feasible when the framework is able to handle plural
+ * forms of <i>all</i> languages correctly. <code>ChoiceFormat</code>
+ * doesn't handle this well, because it attaches a number interval to
+ * each message and selects the message whose interval contains a
+ * given number. This can only handle a finite number of
+ * intervals. But in some languages, like Polish, one plural case
+ * applies to infinitely many intervals (e.g., the plural case applies to
+ * numbers ending with 2, 3, or 4 except those ending with 12, 13, or
+ * 14). Thus <code>ChoiceFormat</code> is not adequate.
+ * </p><p>
+ * <code>PluralFormat</code> deals with this by breaking the problem
+ * into two parts:
+ * <ul>
+ * <li>It uses <code>PluralRules</code> that can define more complex
+ * conditions for a plural case than just a single interval. These plural
+ * rules define both what plural cases exist in a language, and to
+ * which numbers these cases apply.
+ * <li>It provides predefined plural rules for many languages. Thus, the programmer
+ * need not worry about the plural cases of a language and
+ * does not have to define the plural cases; they can simply
+ * use the predefined keywords. The whole plural formatting of messages can
+ * be done using localized patterns from resource bundles. For predefined plural
+ * rules, see the CLDR <i>Language Plural Rules</i> page at
+ * https://unicode-org.github.io/cldr-staging/charts/latest/supplemental/language_plural_rules.html
+ * </ul>
+ * </p>
+ * <h4>Usage of <code>PluralFormat</code></h4>
+ * <p>Note: Typically, plural formatting is done via <code>MessageFormat</code>
+ * with a <code>plural</code> argument type,
+ * rather than using a stand-alone <code>PluralFormat</code>.
+ * </p><p>
+ * This discussion assumes that you use <code>PluralFormat</code> with
+ * a predefined set of plural rules. You can create one using one of
+ * the constructors that takes a <code>locale</code> object. To
+ * specify the message pattern, you can either pass it to the
+ * constructor or set it explicitly using the
+ * <code>applyPattern()</code> method. The <code>format()</code>
+ * method takes a number object and selects the message of the
+ * matching plural case. This message will be returned.
+ * </p>
+ * <h5>Patterns and Their Interpretation</h5>
+ * <p>
+ * The pattern text defines the message output for each plural case of the
+ * specified locale. Syntax:
+ * <pre>
+ * pluralStyle = [offsetValue] (selector '{' message '}')+
+ * offsetValue = "offset:" number
+ * selector = explicitValue | keyword
+ * explicitValue = '=' number // adjacent, no white space in between
+ * keyword = [^[[:Pattern_Syntax:][:Pattern_White_Space:]]]+
+ * message: see {@link MessageFormat}
+ * </pre>
+ * Pattern_White_Space between syntax elements is ignored, except
+ * between the {curly braces} and their sub-message,
+ * and between the '=' and the number of an explicitValue.
+ *
+ * </p><p>
+ * There are 6 predefined casekeyword in CLDR/ICU - 'zero', 'one', 'two', 'few', 'many' and
+ * 'other'. You always have to define a message text for the default plural case
+ * <code>other</code> which is contained in every rule set.
+ * If you do not specify a message text for a particular plural case, the
+ * message text of the plural case <code>other</code> gets assigned to this
+ * plural case.
+ * </p><p>
+ * When formatting, the input number is first matched against the explicitValue clauses.
+ * If there is no exact-number match, then a keyword is selected by calling
+ * the <code>PluralRules</code> with the input number <em>minus the offset</em>.
+ * (The offset defaults to 0 if it is omitted from the pattern string.)
+ * If there is no clause with that keyword, then the "other" clauses is returned.
+ * </p><p>
+ * An unquoted pound sign (<code>#</code>) in the selected sub-message
+ * itself (i.e., outside of arguments nested in the sub-message)
+ * is replaced by the input number minus the offset.
+ * The number-minus-offset value is formatted using a
+ * <code>NumberFormat</code> for the <code>PluralFormat</code>'s locale. If you
+ * need special number formatting, you have to use a <code>MessageFormat</code>
+ * and explicitly specify a <code>NumberFormat</code> argument.
+ * <strong>Note:</strong> That argument is formatting without subtracting the offset!
+ * If you need a custom format and have a non-zero offset, then you need to pass the
+ * number-minus-offset value as a separate parameter.
+ * </p>
+ * For a usage example, see the {@link MessageFormat} class documentation.
+ *
+ * <h4>Defining Custom Plural Rules</h4>
+ * <p>If you need to use <code>PluralFormat</code> with custom rules, you can
+ * create a <code>PluralRules</code> object and pass it to
+ * <code>PluralFormat</code>'s constructor. If you also specify a locale in this
+ * constructor, this locale will be used to format the number in the message
+ * texts.
+ * </p><p>
+ * For more information about <code>PluralRules</code>, see
+ * {@link PluralRules}.
+ * </p>
+ *
+ * ported from Java
+ * @stable ICU 4.0
+ */
+
+class U_I18N_API PluralFormat : public Format {
+public:
+
+ /**
+ * Creates a new cardinal-number <code>PluralFormat</code> for the default locale.
+ * This locale will be used to get the set of plural rules and for standard
+ * number formatting.
+ * @param status output param set to success/failure code on exit, which
+ * must not indicate a failure before the function call.
+ * @stable ICU 4.0
+ */
+ PluralFormat(UErrorCode& status);
+
+ /**
+ * Creates a new cardinal-number <code>PluralFormat</code> for a given locale.
+ * @param locale the <code>PluralFormat</code> will be configured with
+ * rules for this locale. This locale will also be used for
+ * standard number formatting.
+ * @param status output param set to success/failure code on exit, which
+ * must not indicate a failure before the function call.
+ * @stable ICU 4.0
+ */
+ PluralFormat(const Locale& locale, UErrorCode& status);
+
+ /**
+ * Creates a new <code>PluralFormat</code> for a given set of rules.
+ * The standard number formatting will be done using the default locale.
+ * @param rules defines the behavior of the <code>PluralFormat</code>
+ * object.
+ * @param status output param set to success/failure code on exit, which
+ * must not indicate a failure before the function call.
+ * @stable ICU 4.0
+ */
+ PluralFormat(const PluralRules& rules, UErrorCode& status);
+
+ /**
+ * Creates a new <code>PluralFormat</code> for a given set of rules.
+ * The standard number formatting will be done using the given locale.
+ * @param locale the default number formatting will be done using this
+ * locale.
+ * @param rules defines the behavior of the <code>PluralFormat</code>
+ * object.
+ * @param status output param set to success/failure code on exit, which
+ * must not indicate a failure before the function call.
+ * @stable ICU 4.0
+ * <p>
+ * <h4>Sample code</h4>
+ * \snippet samples/plurfmtsample/plurfmtsample.cpp PluralFormatExample1
+ * \snippet samples/plurfmtsample/plurfmtsample.cpp PluralFormatExample
+ * <p>
+ */
+ PluralFormat(const Locale& locale, const PluralRules& rules, UErrorCode& status);
+
+ /**
+ * Creates a new <code>PluralFormat</code> for the plural type.
+ * The standard number formatting will be done using the given locale.
+ * @param locale the default number formatting will be done using this
+ * locale.
+ * @param type The plural type (e.g., cardinal or ordinal).
+ * @param status output param set to success/failure code on exit, which
+ * must not indicate a failure before the function call.
+ * @stable ICU 50
+ */
+ PluralFormat(const Locale& locale, UPluralType type, UErrorCode& status);
+
+ /**
+ * Creates a new cardinal-number <code>PluralFormat</code> for a given pattern string.
+ * The default locale will be used to get the set of plural rules and for
+ * standard number formatting.
+ * @param pattern the pattern for this <code>PluralFormat</code>.
+ * errors are returned to status if the pattern is invalid.
+ * @param status output param set to success/failure code on exit, which
+ * must not indicate a failure before the function call.
+ * @stable ICU 4.0
+ */
+ PluralFormat(const UnicodeString& pattern, UErrorCode& status);
+
+ /**
+ * Creates a new cardinal-number <code>PluralFormat</code> for a given pattern string and
+ * locale.
+ * The locale will be used to get the set of plural rules and for
+ * standard number formatting.
+ * @param locale the <code>PluralFormat</code> will be configured with
+ * rules for this locale. This locale will also be used for
+ * standard number formatting.
+ * @param pattern the pattern for this <code>PluralFormat</code>.
+ * errors are returned to status if the pattern is invalid.
+ * @param status output param set to success/failure code on exit, which
+ * must not indicate a failure before the function call.
+ * @stable ICU 4.0
+ */
+ PluralFormat(const Locale& locale, const UnicodeString& pattern, UErrorCode& status);
+
+ /**
+ * Creates a new <code>PluralFormat</code> for a given set of rules, a
+ * pattern and a locale.
+ * @param rules defines the behavior of the <code>PluralFormat</code>
+ * object.
+ * @param pattern the pattern for this <code>PluralFormat</code>.
+ * errors are returned to status if the pattern is invalid.
+ * @param status output param set to success/failure code on exit, which
+ * must not indicate a failure before the function call.
+ * @stable ICU 4.0
+ */
+ PluralFormat(const PluralRules& rules,
+ const UnicodeString& pattern,
+ UErrorCode& status);
+
+ /**
+ * Creates a new <code>PluralFormat</code> for a given set of rules, a
+ * pattern and a locale.
+ * @param locale the <code>PluralFormat</code> will be configured with
+ * rules for this locale. This locale will also be used for
+ * standard number formatting.
+ * @param rules defines the behavior of the <code>PluralFormat</code>
+ * object.
+ * @param pattern the pattern for this <code>PluralFormat</code>.
+ * errors are returned to status if the pattern is invalid.
+ * @param status output param set to success/failure code on exit, which
+ * must not indicate a failure before the function call.
+ * @stable ICU 4.0
+ */
+ PluralFormat(const Locale& locale,
+ const PluralRules& rules,
+ const UnicodeString& pattern,
+ UErrorCode& status);
+
+ /**
+ * Creates a new <code>PluralFormat</code> for a plural type, a
+ * pattern and a locale.
+ * @param locale the <code>PluralFormat</code> will be configured with
+ * rules for this locale. This locale will also be used for
+ * standard number formatting.
+ * @param type The plural type (e.g., cardinal or ordinal).
+ * @param pattern the pattern for this <code>PluralFormat</code>.
+ * errors are returned to status if the pattern is invalid.
+ * @param status output param set to success/failure code on exit, which
+ * must not indicate a failure before the function call.
+ * @stable ICU 50
+ */
+ PluralFormat(const Locale& locale,
+ UPluralType type,
+ const UnicodeString& pattern,
+ UErrorCode& status);
+
+ /**
+ * copy constructor.
+ * @stable ICU 4.0
+ */
+ PluralFormat(const PluralFormat& other);
+
+ /**
+ * Destructor.
+ * @stable ICU 4.0
+ */
+ virtual ~PluralFormat();
+
+ /**
+ * Sets the pattern used by this plural format.
+ * The method parses the pattern and creates a map of format strings
+ * for the plural rules.
+ * Patterns and their interpretation are specified in the class description.
+ *
+ * @param pattern the pattern for this plural format
+ * errors are returned to status if the pattern is invalid.
+ * @param status output param set to success/failure code on exit, which
+ * must not indicate a failure before the function call.
+ * @stable ICU 4.0
+ */
+ void applyPattern(const UnicodeString& pattern, UErrorCode& status);
+
+
+ using Format::format;
+
+ /**
+ * Formats a plural message for a given number.
+ *
+ * @param number a number for which the plural message should be formatted
+ * for. If no pattern has been applied to this
+ * <code>PluralFormat</code> object yet, the formatted number
+ * will be returned.
+ * @param status output param set to success/failure code on exit, which
+ * must not indicate a failure before the function call.
+ * @return the string containing the formatted plural message.
+ * @stable ICU 4.0
+ */
+ UnicodeString format(int32_t number, UErrorCode& status) const;
+
+ /**
+ * Formats a plural message for a given number.
+ *
+ * @param number a number for which the plural message should be formatted
+ * for. If no pattern has been applied to this
+ * PluralFormat object yet, the formatted number
+ * will be returned.
+ * @param status output param set to success or failure code on exit, which
+ * must not indicate a failure before the function call.
+ * @return the string containing the formatted plural message.
+ * @stable ICU 4.0
+ */
+ UnicodeString format(double number, UErrorCode& status) const;
+
+ /**
+ * Formats a plural message for a given number.
+ *
+ * @param number a number for which the plural message should be formatted
+ * for. If no pattern has been applied to this
+ * <code>PluralFormat</code> object yet, the formatted number
+ * will be returned.
+ * @param appendTo output parameter to receive result.
+ * result is appended to existing contents.
+ * @param pos On input: an alignment field, if desired.
+ * On output: the offsets of the alignment field.
+ * @param status output param set to success/failure code on exit, which
+ * must not indicate a failure before the function call.
+ * @return the string containing the formatted plural message.
+ * @stable ICU 4.0
+ */
+ UnicodeString& format(int32_t number,
+ UnicodeString& appendTo,
+ FieldPosition& pos,
+ UErrorCode& status) const;
+
+ /**
+ * Formats a plural message for a given number.
+ *
+ * @param number a number for which the plural message should be formatted
+ * for. If no pattern has been applied to this
+ * PluralFormat object yet, the formatted number
+ * will be returned.
+ * @param appendTo output parameter to receive result.
+ * result is appended to existing contents.
+ * @param pos On input: an alignment field, if desired.
+ * On output: the offsets of the alignment field.
+ * @param status output param set to success/failure code on exit, which
+ * must not indicate a failure before the function call.
+ * @return the string containing the formatted plural message.
+ * @stable ICU 4.0
+ */
+ UnicodeString& format(double number,
+ UnicodeString& appendTo,
+ FieldPosition& pos,
+ UErrorCode& status) const;
+
+#ifndef U_HIDE_DEPRECATED_API
+ /**
+ * Sets the locale used by this <code>PluraFormat</code> object.
+ * Note: Calling this method resets this <code>PluraFormat</code> object,
+ * i.e., a pattern that was applied previously will be removed,
+ * and the NumberFormat is set to the default number format for
+ * the locale. The resulting format behaves the same as one
+ * constructed from {@link #PluralFormat(const Locale& locale, UPluralType type, UErrorCode& status)}
+ * with UPLURAL_TYPE_CARDINAL.
+ * @param locale the <code>locale</code> to use to configure the formatter.
+ * @param status output param set to success/failure code on exit, which
+ * must not indicate a failure before the function call.
+ * @deprecated ICU 50 This method clears the pattern and might create
+ * a different kind of PluralRules instance;
+ * use one of the constructors to create a new instance instead.
+ */
+ void setLocale(const Locale& locale, UErrorCode& status);
+#endif /* U_HIDE_DEPRECATED_API */
+
+ /**
+ * Sets the number format used by this formatter. You only need to
+ * call this if you want a different number format than the default
+ * formatter for the locale.
+ * @param format the number format to use.
+ * @param status output param set to success/failure code on exit, which
+ * must not indicate a failure before the function call.
+ * @stable ICU 4.0
+ */
+ void setNumberFormat(const NumberFormat* format, UErrorCode& status);
+
+ /**
+ * Assignment operator
+ *
+ * @param other the PluralFormat object to copy from.
+ * @stable ICU 4.0
+ */
+ PluralFormat& operator=(const PluralFormat& other);
+
+ /**
+ * Return true if another object is semantically equal to this one.
+ *
+ * @param other the PluralFormat object to be compared with.
+ * @return true if other is semantically equal to this.
+ * @stable ICU 4.0
+ */
+ virtual bool operator==(const Format& other) const override;
+
+ /**
+ * Return true if another object is semantically unequal to this one.
+ *
+ * @param other the PluralFormat object to be compared with.
+ * @return true if other is semantically unequal to this.
+ * @stable ICU 4.0
+ */
+ virtual bool operator!=(const Format& other) const;
+
+ /**
+ * Clones this Format object polymorphically. The caller owns the
+ * result and should delete it when done.
+ * @stable ICU 4.0
+ */
+ virtual PluralFormat* clone() const override;
+
+ /**
+ * Formats a plural message for a number taken from a Formattable object.
+ *
+ * @param obj The object containing a number for which the
+ * plural message should be formatted.
+ * The object must be of a numeric type.
+ * @param appendTo output parameter to receive result.
+ * Result is appended to existing contents.
+ * @param pos On input: an alignment field, if desired.
+ * On output: the offsets of the alignment field.
+ * @param status output param filled with success/failure status.
+ * @return Reference to 'appendTo' parameter.
+ * @stable ICU 4.0
+ */
+ UnicodeString& format(const Formattable& obj,
+ UnicodeString& appendTo,
+ FieldPosition& pos,
+ UErrorCode& status) const override;
+
+ /**
+ * Returns the pattern from applyPattern() or constructor().
+ *
+ * @param appendTo output parameter to receive result.
+ * Result is appended to existing contents.
+ * @return the UnicodeString with inserted pattern.
+ * @stable ICU 4.0
+ */
+ UnicodeString& toPattern(UnicodeString& appendTo);
+
+ /**
+ * This method is not yet supported by <code>PluralFormat</code>.
+ * <P>
+ * Before calling, set parse_pos.index to the offset you want to start
+ * parsing at in the source. After calling, parse_pos.index is the end of
+ * the text you parsed. If error occurs, index is unchanged.
+ * <P>
+ * When parsing, leading whitespace is discarded (with a successful parse),
+ * while trailing whitespace is left as is.
+ * <P>
+ * See Format::parseObject() for more.
+ *
+ * @param source The string to be parsed into an object.
+ * @param result Formattable to be set to the parse result.
+ * If parse fails, return contents are undefined.
+ * @param parse_pos The position to start parsing at. Upon return
+ * this param is set to the position after the
+ * last character successfully parsed. If the
+ * source is not parsed successfully, this param
+ * will remain unchanged.
+ * @stable ICU 4.0
+ */
+ virtual void parseObject(const UnicodeString& source,
+ Formattable& result,
+ ParsePosition& parse_pos) const override;
+
+ /**
+ * ICU "poor man's RTTI", returns a UClassID for this class.
+ *
+ * @stable ICU 4.0
+ *
+ */
+ static UClassID U_EXPORT2 getStaticClassID(void);
+
+ /**
+ * ICU "poor man's RTTI", returns a UClassID for the actual class.
+ *
+ * @stable ICU 4.0
+ */
+ virtual UClassID getDynamicClassID() const override;
+
+private:
+ /**
+ * @internal (private)
+ */
+ class U_I18N_API PluralSelector : public UMemory {
+ public:
+ virtual ~PluralSelector();
+ /**
+ * Given a number, returns the appropriate PluralFormat keyword.
+ *
+ * @param context worker object for the selector.
+ * @param number The number to be plural-formatted.
+ * @param ec Error code.
+ * @return The selected PluralFormat keyword.
+ * @internal (private)
+ */
+ virtual UnicodeString select(void *context, double number, UErrorCode& ec) const = 0;
+ };
+
+ class U_I18N_API PluralSelectorAdapter : public PluralSelector {
+ public:
+ PluralSelectorAdapter() : pluralRules(nullptr) {
+ }
+
+ virtual ~PluralSelectorAdapter();
+
+ virtual UnicodeString select(void *context, double number, UErrorCode& /*ec*/) const override;
+
+ void reset();
+
+ PluralRules* pluralRules;
+ };
+
+ Locale locale;
+ MessagePattern msgPattern;
+ NumberFormat* numberFormat;
+ double offset;
+ PluralSelectorAdapter pluralRulesWrapper;
+
+ PluralFormat() = delete; // default constructor not implemented
+ void init(const PluralRules* rules, UPluralType type, UErrorCode& status);
+ /**
+ * Copies dynamically allocated values (pointer fields).
+ * Others are copied using their copy constructors and assignment operators.
+ */
+ void copyObjects(const PluralFormat& other);
+
+ UnicodeString& format(const Formattable& numberObject, double number,
+ UnicodeString& appendTo,
+ FieldPosition& pos,
+ UErrorCode& status) const;
+
+ /**
+ * Finds the PluralFormat sub-message for the given number, or the "other" sub-message.
+ * @param pattern A MessagePattern.
+ * @param partIndex the index of the first PluralFormat argument style part.
+ * @param selector the PluralSelector for mapping the number (minus offset) to a keyword.
+ * @param context worker object for the selector.
+ * @param number a number to be matched to one of the PluralFormat argument's explicit values,
+ * or mapped via the PluralSelector.
+ * @param ec ICU error code.
+ * @return the sub-message start part index.
+ */
+ static int32_t findSubMessage(
+ const MessagePattern& pattern, int32_t partIndex,
+ const PluralSelector& selector, void *context, double number, UErrorCode& ec);
+
+ void parseType(const UnicodeString& source, const NFRule *rbnfLenientScanner,
+ Formattable& result, FieldPosition& pos) const;
+
+ friend class MessageFormat;
+ friend class NFRule;
+};
+
+U_NAMESPACE_END
+
+#endif /* #if !UCONFIG_NO_FORMATTING */
+
+#endif /* U_SHOW_CPLUSPLUS_API */
+
+#endif // _PLURFMT
+//eof