icuSources/i18n/unicode/plurrule.h

   1 /*
   2 *******************************************************************************
   3 * Copyright (C) 2008-2012, International Business Machines Corporation and
   4 * others. All Rights Reserved.
   5 *******************************************************************************
   6 *
   7 *
   8 * File PLURRULE.H
   9 *
  10 * Modification History:*
  11 *   Date        Name        Description
  12 *
  13 ********************************************************************************
  14 */
  15
  16 #ifndef PLURRULE
  17 #define PLURRULE
  18
  19 #include "unicode/utypes.h"
  20
  21 /**
  22  * \file
  23  * \brief C++ API: PluralRules object
  24  */
  25
  26 #if !UCONFIG_NO_FORMATTING
  27
  28 #include "unicode/format.h"
  29
  30 /**
  31  * Value returned by PluralRules::getUniqueKeywordValue() when there is no
  32  * unique value to return.
  33  * @stable ICU 4.8
  34  */
  35 #define UPLRULES_NO_UNIQUE_VALUE ((double)-0.00123456777)
  36
  37 U_NAMESPACE_BEGIN
  38
  39 class Hashtable;
  40 class RuleChain;
  41 class RuleParser;
  42 class PluralKeywordEnumeration;
  43
  44 /**
  45  * Defines rules for mapping non-negative numeric values onto a small set of
  46  * keywords. Rules are constructed from a text description, consisting
  47  * of a series of keywords and conditions.  The {@link #select} method
  48  * examines each condition in order and returns the keyword for the
  49  * first condition that matches the number.  If none match,
  50  * default rule(other) is returned.
  51  *
  52  * For more information, details, and tips for writing rules, see the
  53  * LDML spec, C.11 Language Plural Rules:
  54  * http://www.unicode.org/draft/reports/tr35/tr35.html#Language_Plural_Rules
  55  *
  56  * Examples:<pre>
  57  *   "one: n is 1; few: n in 2..4"</pre>
  58  *  This defines two rules, for 'one' and 'few'.  The condition for
  59  *  'one' is "n is 1" which means that the number must be equal to
  60  *  1 for this condition to pass.  The condition for 'few' is
  61  *  "n in 2..4" which means that the number must be between 2 and
  62  *  4 inclusive for this condition to pass.  All other numbers
  63  *  are assigned the keyword "other" by the default rule.
  64  *  </p><pre>
  65  *    "zero: n is 0; one: n is 1; zero: n mod 100 in 1..19"</pre>
  66  *  This illustrates that the same keyword can be defined multiple times.
  67  *  Each rule is examined in order, and the first keyword whose condition
  68  *  passes is the one returned.  Also notes that a modulus is applied
  69  *  to n in the last rule.  Thus its condition holds for 119, 219, 319...
  70  *  </p><pre>
  71  *    "one: n is 1; few: n mod 10 in 2..4 and n mod 100 not in 12..14"</pre>
  72  *  This illustrates conjunction and negation.  The condition for 'few'
  73  *  has two parts, both of which must be met: "n mod 10 in 2..4" and
  74  *  "n mod 100 not in 12..14".  The first part applies a modulus to n
  75  *  before the test as in the previous example.  The second part applies
  76  *  a different modulus and also uses negation, thus it matches all
  77  *  numbers _not_ in 12, 13, 14, 112, 113, 114, 212, 213, 214...
  78  *  </p>
  79  *  <p>
  80  * Syntax:<pre>
  81  * \code
  82  * rules         = rule (';' rule)*
  83  * rule          = keyword ':' condition
  84  * keyword       = <identifier>
  85  * condition     = and_condition ('or' and_condition)*
  86  * and_condition = relation ('and' relation)*
  87  * relation      = is_relation | in_relation | within_relation | 'n' <EOL>
  88  * is_relation   = expr 'is' ('not')? value
  89  * in_relation   = expr ('not')? 'in' range_list
  90  * within_relation = expr ('not')? 'within' range
  91  * expr          = 'n' ('mod' value)?
  92  * range_list    = (range | value) (',' range_list)*
  93  * value         = digit+
  94  * digit         = 0|1|2|3|4|5|6|7|8|9
  95  * range         = value'..'value
  96  * \endcode
  97  * </pre></p>
  98  * <p>
  99  * An "identifier" is a sequence of characters that do not have the
 100  * Unicode Pattern_Syntax or Pattern_White_Space properties.
 101  * <p>
 102  * The difference between 'in' and 'within' is that 'in' only includes
 103  * integers in the specified range, while 'within' includes all values.</p>
 104  * <p>
 105  * Keywords
 106  * could be defined by users or from ICU locale data. There are 6
 107  * predefined values in ICU - 'zero', 'one', 'two', 'few', 'many' and
 108  * 'other'. Callers need to check the value of keyword returned by
 109  * {@link #select} method.
 110  * </p>
 111  *
 112  * Examples:<pre>
 113  * UnicodeString keyword = pl->select(number);
 114  * if (keyword== UnicodeString("one") {
 115  *     ...
 116  * }
 117  * else if ( ... )
 118  * </pre>
 119  * <strong>Note:</strong><br>
 120  *  <p>
 121  *   ICU defines plural rules for many locales based on CLDR <i>Language Plural Rules</i>.
 122  *   For these predefined rules, see CLDR page at
 123  *    http://unicode.org/repos/cldr-tmp/trunk/diff/supplemental/language_plural_rules.html
 124  * </p>
 125  */
 126 class U_I18N_API PluralRules : public UObject {
 127 public:
 128
 129     /**
 130      * Constructor.
 131      * @param status  Output param set to success/failure code on exit, which
 132      *                must not indicate a failure before the function call.
 133      *
 134      * @stable ICU 4.0
 135      */
 136     PluralRules(UErrorCode& status);
 137
 138     /**
 139      * Copy constructor.
 140      * @stable ICU 4.0
 141      */
 142     PluralRules(const PluralRules& other);
 143
 144     /**
 145      * Destructor.
 146      * @stable ICU 4.0
 147      */
 148     virtual ~PluralRules();
 149
 150     /**
 151      * Clone
 152      * @stable ICU 4.0
 153      */
 154     PluralRules* clone() const;
 155
 156     /**
 157       * Assignment operator.
 158       * @stable ICU 4.0
 159       */
 160     PluralRules& operator=(const PluralRules&);
 161
 162     /**
 163      * Creates a PluralRules from a description if it is parsable, otherwise
 164      * returns NULL.
 165      *
 166      * @param description rule description
 167      * @param status      Output param set to success/failure code on exit, which
 168      *                    must not indicate a failure before the function call.
 169      * @return            new PluralRules pointer. NULL if there is an error.
 170      * @stable ICU 4.0
 171      */
 172     static PluralRules* U_EXPORT2 createRules(const UnicodeString& description,
 173                                               UErrorCode& status);
 174
 175     /**
 176      * The default rules that accept any number.
 177      *
 178      * @param status  Output param set to success/failure code on exit, which
 179      *                must not indicate a failure before the function call.
 180      * @return        new PluralRules pointer. NULL if there is an error.
 181      * @stable ICU 4.0
 182      */
 183     static PluralRules* U_EXPORT2 createDefaultRules(UErrorCode& status);
 184
 185     /**
 186      * Provides access to the predefined <code>PluralRules</code> for a given
 187      * locale.
 188      *
 189      * @param locale  The locale for which a <code>PluralRules</code> object is
 190      *                returned.
 191      * @param status  Output param set to success/failure code on exit, which
 192      *                must not indicate a failure before the function call.
 193      * @return        The predefined <code>PluralRules</code> object pointer for
 194      *                this locale. If there's no predefined rules for this locale,
 195      *                the rules for the closest parent in the locale hierarchy
 196      *                that has one will  be returned.  The final fallback always
 197      *                returns the default 'other' rules.
 198      * @stable ICU 4.0
 199      */
 200     static PluralRules* U_EXPORT2 forLocale(const Locale& locale, UErrorCode& status);
 201
 202     /**
 203      * Given a number, returns the keyword of the first rule that applies to
 204      * the number.  This function can be used with isKeyword* functions to
 205      * determine the keyword for default plural rules.
 206      *
 207      * @param number  The number for which the rule has to be determined.
 208      * @return        The keyword of the selected rule.
 209      * @stable ICU 4.0
 210      */
 211     UnicodeString select(int32_t number) const;
 212
 213     /**
 214      * Given a number, returns the keyword of the first rule that applies to
 215      * the number.  This function can be used with isKeyword* functions to
 216      * determine the keyword for default plural rules.
 217      *
 218      * @param number  The number for which the rule has to be determined.
 219      * @return        The keyword of the selected rule.
 220      * @stable ICU 4.0
 221      */
 222     UnicodeString select(double number) const;
 223
 224     /**
 225      * Returns a list of all rule keywords used in this <code>PluralRules</code>
 226      * object.  The rule 'other' is always present by default.
 227      *
 228      * @param status Output param set to success/failure code on exit, which
 229      *               must not indicate a failure before the function call.
 230      * @return       StringEnumeration with the keywords.
 231      *               The caller must delete the object.
 232      * @stable ICU 4.0
 233      */
 234     StringEnumeration* getKeywords(UErrorCode& status) const;
 235
 236     /**
 237      * Returns a unique value for this keyword if it exists, else the constant
 238      * UPLRULES_NO_UNIQUE_VALUE.
 239      *
 240      * @param keyword The keyword.
 241      * @return        The unique value that generates the keyword, or
 242      *                UPLRULES_NO_UNIQUE_VALUE if the keyword is undefined or there is no
 243      *                unique value that generates this keyword.
 244      * @stable ICU 4.8
 245      */
 246     double getUniqueKeywordValue(const UnicodeString& keyword);
 247
 248     /**
 249      * Returns all the values for which select() would return the keyword.  If
 250      * the keyword is unknown, returns no values, but this is not an error.  If
 251      * the number of values is unlimited, returns no values and -1 as the
 252      * count.
 253      *
 254      * The number of returned values is typically small.
 255      *
 256      * @param keyword      The keyword.
 257      * @param dest         Array into which to put the returned values.  May
 258      *                     be NULL if destCapacity is 0.
 259      * @param destCapacity The capacity of the array, must be at least 0.
 260      * @param status       The error code.
 261      * @return             The count of values available, or -1.  This count
 262      *                     can be larger than destCapacity, but no more than
 263      *                     destCapacity values will be written.
 264      * @stable ICU 4.8
 265      */
 266     int32_t getAllKeywordValues(const UnicodeString &keyword,
 267                                 double *dest, int32_t destCapacity,
 268                                 UErrorCode& status);
 269
 270     /**
 271      * Returns sample values for which select() would return the keyword.  If
 272      * the keyword is unknown, returns no values, but this is not an error.
 273      *
 274      * The number of returned values is typically small.
 275      *
 276      * @param keyword      The keyword.
 277      * @param dest         Array into which to put the returned values.  May
 278      *                     be NULL if destCapacity is 0.
 279      * @param destCapacity The capacity of the array, must be at least 0.
 280      * @param status       The error code.
 281      * @return             The count of values written.
 282      *                     If more than destCapacity samples are available, then
 283      *                     only destCapacity are written, and destCapacity is returned as the count,
 284      *                     rather than setting a U_BUFFER_OVERFLOW_ERROR.
 285      *                     (The actual number of keyword values could be unlimited.)
 286      * @stable ICU 4.8
 287      */
 288     int32_t getSamples(const UnicodeString &keyword,
 289                        double *dest, int32_t destCapacity,
 290                        UErrorCode& status);
 291
 292     /**
 293      * Returns TRUE if the given keyword is defined in this
 294      * <code>PluralRules</code> object.
 295      *
 296      * @param keyword  the input keyword.
 297      * @return         TRUE if the input keyword is defined.
 298      *                 Otherwise, return FALSE.
 299      * @stable ICU 4.0
 300      */
 301     UBool isKeyword(const UnicodeString& keyword) const;
 302
 303
 304     /**
 305      * Returns keyword for default plural form.
 306      *
 307      * @return         keyword for default plural form.
 308      * @stable ICU 4.0
 309      */
 310     UnicodeString getKeywordOther() const;
 311
 312     /**
 313      * Compares the equality of two PluralRules objects.
 314      *
 315      * @param other The other PluralRules object to be compared with.
 316      * @return      True if the given PluralRules is the same as this
 317      *              PluralRules; false otherwise.
 318      * @stable ICU 4.0
 319      */
 320     virtual UBool operator==(const PluralRules& other) const;
 321
 322     /**
 323      * Compares the inequality of two PluralRules objects.
 324      *
 325      * @param other The PluralRules object to be compared with.
 326      * @return      True if the given PluralRules is not the same as this
 327      *              PluralRules; false otherwise.
 328      * @stable ICU 4.0
 329      */
 330     UBool operator!=(const PluralRules& other) const  {return !operator==(other);}
 331
 332
 333     /**
 334      * ICU "poor man's RTTI", returns a UClassID for this class.
 335      *
 336      * @stable ICU 4.0
 337      *
 338     */
 339     static UClassID U_EXPORT2 getStaticClassID(void);
 340
 341     /**
 342      * ICU "poor man's RTTI", returns a UClassID for the actual class.
 343      *
 344      * @stable ICU 4.0
 345      */
 346     virtual UClassID getDynamicClassID() const;
 347
 348
 349 private:
 350     RuleChain  *mRules;
 351     RuleParser *mParser;
 352     double     *mSamples;
 353     int32_t    *mSampleInfo;
 354     int32_t    mSampleInfoCount;
 355
 356     PluralRules();   // default constructor not implemented
 357     int32_t getRepeatLimit() const;
 358     void parseDescription(UnicodeString& ruleData, RuleChain& rules, UErrorCode &status);
 359     void getNextLocale(const UnicodeString& localeData, int32_t* curIndex, UnicodeString& localeName);
 360     void addRules(RuleChain& rules);
 361     int32_t getNumberValue(const UnicodeString& token) const;
 362     UnicodeString getRuleFromResource(const Locale& locale, UErrorCode& status);
 363
 364     static const int32_t MAX_SAMPLES = 3;
 365
 366     int32_t getSamplesInternal(const UnicodeString &keyword, double *dest,
 367                                int32_t destCapacity, UBool includeUnlimited,
 368                                UErrorCode& status);
 369     int32_t getKeywordIndex(const UnicodeString& keyword,
 370                             UErrorCode& status) const;
 371     void initSamples(UErrorCode& status);
 372
 373 };
 374
 375 U_NAMESPACE_END
 376
 377 #endif /* #if !UCONFIG_NO_FORMATTING */
 378
 379 #endif // _PLURRULE
 380 //eof