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1 // © 2016 and later: Unicode, Inc. and others.
2 // License & terms of use: http://www.unicode.org/copyright.html
3 /*
4 *****************************************************************************************
5 * Copyright (C) 2010-2013, International Business Machines
6 * Corporation and others. All Rights Reserved.
7 *****************************************************************************************
8 */
9 
10 #ifndef UPLURALRULES_H
11 #define UPLURALRULES_H
12 
13 #include "unicode/utypes.h"
14 
15 #if !UCONFIG_NO_FORMATTING
16 
17 #include "unicode/uenum.h"
18 
19 #if U_SHOW_CPLUSPLUS_API
20 #include "unicode/localpointer.h"
21 #endif   // U_SHOW_CPLUSPLUS_API
22 
23 #ifndef U_HIDE_INTERNAL_API
24 #include "unicode/unum.h"
25 #endif  /* U_HIDE_INTERNAL_API */
26 
27 // Forward-declaration
28 struct UFormattedNumber;
29 struct UFormattedNumberRange;
30 
31 /**
32  * \file
33  * \brief C API: Plural rules, select plural keywords for numeric values.
34  *
35  * A UPluralRules object defines rules for mapping non-negative numeric
36  * values onto a small set of keywords. Rules are constructed from a text
37  * description, consisting of a series of keywords and conditions.
38  * The uplrules_select function examines each condition in order and
39  * returns the keyword for the first condition that matches the number.
40  * If none match, the default rule(other) is returned.
41  *
42  * For more information, see the
43  * LDML spec, Part 3.5 Language Plural Rules:
44  * https://www.unicode.org/reports/tr35/tr35-numbers.html#Language_Plural_Rules
45  *
46  * Keywords: ICU locale data has 6 predefined values -
47  * 'zero', 'one', 'two', 'few', 'many' and 'other'. Callers need to check
48  * the value of keyword returned by the uplrules_select function.
49  *
50  * These are based on CLDR <i>Language Plural Rules</i>. For these
51  * predefined rules, see the CLDR page at
52  * https://unicode-org.github.io/cldr-staging/charts/latest/supplemental/language_plural_rules.html
53  */
54 
55 /**
56  * Type of plurals and PluralRules.
57  * @stable ICU 50
58  */
59 enum UPluralType {
60     /**
61      * Plural rules for cardinal numbers: 1 file vs. 2 files.
62      * @stable ICU 50
63      */
64     UPLURAL_TYPE_CARDINAL,
65     /**
66      * Plural rules for ordinal numbers: 1st file, 2nd file, 3rd file, 4th file, etc.
67      * @stable ICU 50
68      */
69     UPLURAL_TYPE_ORDINAL,
70 #ifndef U_HIDE_DEPRECATED_API
71     /**
72      * One more than the highest normal UPluralType value.
73      * @deprecated ICU 58 The numeric value may change over time, see ICU ticket #12420.
74      */
75     UPLURAL_TYPE_COUNT
76 #endif  /* U_HIDE_DEPRECATED_API */
77 };
78 /**
79  * @stable ICU 50
80  */
81 typedef enum UPluralType UPluralType;
82 
83 /**
84  * Opaque UPluralRules object for use in C programs.
85  * @stable ICU 4.8
86  */
87 struct UPluralRules;
88 typedef struct UPluralRules UPluralRules;  /**< C typedef for struct UPluralRules. @stable ICU 4.8 */
89 
90 /**
91  * Opens a new UPluralRules object using the predefined cardinal-number plural rules for a
92  * given locale.
93  * Same as uplrules_openForType(locale, UPLURAL_TYPE_CARDINAL, status).
94  * @param locale The locale for which the rules are desired.
95  * @param status A pointer to a UErrorCode to receive any errors.
96  * @return A UPluralRules for the specified locale, or NULL if an error occurred.
97  * @stable ICU 4.8
98  */
99 U_CAPI UPluralRules* U_EXPORT2
100 uplrules_open(const char *locale, UErrorCode *status);
101 
102 /**
103  * Opens a new UPluralRules object using the predefined plural rules for a
104  * given locale and the plural type.
105  * @param locale The locale for which the rules are desired.
106  * @param type The plural type (e.g., cardinal or ordinal).
107  * @param status A pointer to a UErrorCode to receive any errors.
108  * @return A UPluralRules for the specified locale, or NULL if an error occurred.
109  * @stable ICU 50
110  */
111 U_CAPI UPluralRules* U_EXPORT2
112 uplrules_openForType(const char *locale, UPluralType type, UErrorCode *status);
113 
114 /**
115  * Closes a UPluralRules object. Once closed it may no longer be used.
116  * @param uplrules The UPluralRules object to close.
117  * @stable ICU 4.8
118  */
119 U_CAPI void U_EXPORT2
120 uplrules_close(UPluralRules *uplrules);
121 
122 
123 #if U_SHOW_CPLUSPLUS_API
124 
125 U_NAMESPACE_BEGIN
126 
127 /**
128  * \class LocalUPluralRulesPointer
129  * "Smart pointer" class, closes a UPluralRules via uplrules_close().
130  * For most methods see the LocalPointerBase base class.
131  *
132  * @see LocalPointerBase
133  * @see LocalPointer
134  * @stable ICU 4.8
135  */
136 U_DEFINE_LOCAL_OPEN_POINTER(LocalUPluralRulesPointer, UPluralRules, uplrules_close);
137 
138 U_NAMESPACE_END
139 
140 #endif
141 
142 
143 /**
144  * Given a floating-point number, returns the keyword of the first rule that
145  * applies to the number, according to the supplied UPluralRules object.
146  * @param uplrules The UPluralRules object specifying the rules.
147  * @param number The number for which the rule has to be determined.
148  * @param keyword An output buffer to write the keyword of the rule that
149  *         applies to number.
150  * @param capacity The capacity of the keyword buffer.
151  * @param status A pointer to a UErrorCode to receive any errors.
152  * @return The length of the keyword.
153  * @stable ICU 4.8
154  */
155 U_CAPI int32_t U_EXPORT2
156 uplrules_select(const UPluralRules *uplrules,
157                double number,
158                UChar *keyword, int32_t capacity,
159                UErrorCode *status);
160 
161 /**
162  * Given a formatted number, returns the keyword of the first rule
163  * that applies to the number, according to the supplied UPluralRules object.
164  *
165  * A UFormattedNumber allows you to specify an exponent or trailing zeros,
166  * which can affect the plural category. To get a UFormattedNumber, see
167  * {@link UNumberFormatter}.
168  *
169  * @param uplrules The UPluralRules object specifying the rules.
170  * @param number The formatted number for which the rule has to be determined.
171  * @param keyword The destination buffer for the keyword of the rule that
172  *         applies to the number.
173  * @param capacity The capacity of the keyword buffer.
174  * @param status A pointer to a UErrorCode to receive any errors.
175  * @return The length of the keyword.
176  * @stable ICU 64
177  */
178 U_CAPI int32_t U_EXPORT2
179 uplrules_selectFormatted(const UPluralRules *uplrules,
180                const struct UFormattedNumber* number,
181                UChar *keyword, int32_t capacity,
182                UErrorCode *status);
183 
184 /**
185  * Given a formatted number range, returns the overall plural form of the
186  * range. For example, "3-5" returns "other" in English.
187  *
188  * To get a UFormattedNumberRange, see UNumberRangeFormatter.
189  *
190  * @param uplrules The UPluralRules object specifying the rules.
191  * @param urange The number range onto which the rules will be applied.
192  * @param keyword The destination buffer for the keyword of the rule that
193  *         applies to the number range.
194  * @param capacity The capacity of the keyword buffer.
195  * @param status A pointer to a UErrorCode to receive any errors.
196  * @return The length of the keyword.
197  * @stable ICU 68
198  */
199 U_CAPI int32_t U_EXPORT2
200 uplrules_selectForRange(const UPluralRules *uplrules,
201                const struct UFormattedNumberRange* urange,
202                UChar *keyword, int32_t capacity,
203                UErrorCode *status);
204 
205 #ifndef U_HIDE_INTERNAL_API
206 /**
207  * Given a number, returns the keyword of the first rule that applies to the
208  * number, according to the UPluralRules object and given the number format
209  * specified by the UNumberFormat object.
210  * Note: This internal preview interface may be removed in the future if
211  * an architecturally cleaner solution reaches stable status.
212  * @param uplrules The UPluralRules object specifying the rules.
213  * @param number The number for which the rule has to be determined.
214  * @param fmt The UNumberFormat specifying how the number will be formatted
215  *        (this can affect the plural form, e.g. "1 dollar" vs "1.0 dollars").
216  *        If this is NULL, the function behaves like uplrules_select.
217  * @param keyword An output buffer to write the keyword of the rule that
218  *         applies to number.
219  * @param capacity The capacity of the keyword buffer.
220  * @param status A pointer to a UErrorCode to receive any errors.
221  * @return The length of keyword.
222  * @internal ICU 59 technology preview, may be removed in the future
223  */
224 U_CAPI int32_t U_EXPORT2
225 uplrules_selectWithFormat(const UPluralRules *uplrules,
226                           double number,
227                           const UNumberFormat *fmt,
228                           UChar *keyword, int32_t capacity,
229                           UErrorCode *status);
230 
231 #endif  /* U_HIDE_INTERNAL_API */
232 
233 /**
234  * Creates a string enumeration of all plural rule keywords used in this
235  * UPluralRules object. The rule "other" is always present by default.
236  * @param uplrules The UPluralRules object specifying the rules for
237  *        a given locale.
238  * @param status A pointer to a UErrorCode to receive any errors.
239  * @return a string enumeration over plural rule keywords, or NULL
240  * upon error. The caller is responsible for closing the result.
241  * @stable ICU 59
242  */
243 U_CAPI UEnumeration* U_EXPORT2
244 uplrules_getKeywords(const UPluralRules *uplrules,
245                      UErrorCode *status);
246 
247 #endif /* #if !UCONFIG_NO_FORMATTING */
248 
249 #endif
250