Check in the pristine copy of ICU 4.6...

icu46/source/i18n/unicode/plurrule.h

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