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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
*/
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();
/**
* 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
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