/usr/include/unicode/choicfmt.h (29528B)
ChoiceFormat splits
* the real number line -Inf to +Inf into two
* or more contiguous ranges. Each range is mapped to a
* string. ChoiceFormat is generally used in a
* MessageFormat for displaying grammatically correct
* plurals such as "There are 2 files."
*
* There are two methods of defining a ChoiceFormat; both
* are equivalent. The first is by using a string pattern. This is the
* preferred method in most cases. The second method is through direct
* specification of the arrays that make up the
* ChoiceFormat.
Patterns
* *In most cases, the preferred way to define a
* ChoiceFormat is with a pattern. Here is an example of a
* ChoiceFormat pattern:
0≤are no files|1≤is one file|1<are many files\endhtmlonly * *
or equivalently,
* * \htmlonly0#are no files|1#is one file|1<are many files\endhtmlonly * *
The pattern consists of a number or range specifiers * separated by vertical bars '|' (U+007C). There is no * vertical bar after the last range. Each range specifier is of the * form:
* * \htmlonlyNumber Separator String\endhtmlonly * *
Number is a floating point number that can be parsed by a
* default NumberFormat for the US locale. It gives the
* lower limit of this range. The lower limit is either inclusive or
* exclusive, depending on the separator. The upper limit is
* given by the lower limit of the next range. The Unicode infinity
* sign \htmlonly∞ \endhtmlonly (U+221E) is recognized for positive infinity. It may be preceded by
* '-' (U+002D) to indicate negative infinity.
String is the format string for this range, with special
* characters enclosed in single quotes ('The #
* sign'). Single quotes themselves are indicated by two single
* quotes in a row ('o''clock').
Separator is one of the following single characters: * *
FALSE.TRUE.
* See below for more information about closures.
* *Arrays
* *A ChoiceFormat defining n intervals
* (n >= 2) is specified by three arrays of
* n items:
*
*
double limits[] gives the start of each
* interval. This must be a non-decreasing list of values, none of
* which may be NaN.UBool closures[] determines whether each limit
* value is contained in the interval below it or in the interval
* above it. If closures[i] is FALSE, then
* limits[i] is a member of interval
* i. Otherwise it is a member of interval
* i+1. If no closures array is specified, this is
* equivalent to having all closures be FALSE. Closures
* allow one to specify half-open, open, or closed intervals.UnicodeString formats[] gives the string label
* associated with each interval.Formatting and Parsing
* *During formatting, a number is converted to a
* string. ChoiceFormat accomplishes this by mapping the
* number to an interval using the following rule. Given a number
* X and and index value j in the range
* 0..n-1, where n is the number of ranges:
\endhtmlonly\endhtmlonly * *Xmatchesjif and only if *limit[j] <= X < limit[j+1]* \htmlonly
(This assumes that all closures are FALSE. If some
* closures are TRUE then the relations must be changed to
* <= or < as appropriate.) If there is
* no match, then either the first or last index is used, depending on
* whether the number is too low or too high. Once a number is mapped to
* an interval j, the string formats[j] is
* output.
During parsing, a string is converted to a
* number. ChoiceFormat finds the element
* formats[j] equal to the string, and returns
* limits[j] as the parsed value.
Notes
* *The first limit value does not define a range boundary. For
* example, in the pattern \htmlonly"1.0#a|2.0#b"\endhtmlonly, the
* intervals are [-Inf, 2.0) and [2.0, +Inf]. It appears that the first
* interval should be [1.0, 2.0). However, since all values that are too
* small are mapped to range zero, the first interval is effectively
* [-Inf, 2.0). However, the first limit value is used during
* formatting. In this example, parse("a") returns
* 1.0.
There are no gaps between intervals and the entire number line is
* covered. A ChoiceFormat maps all possible
* double values to a finite set of intervals.
The non-number NaN is mapped to interval zero during
* formatting.
Examples
* *Here is an example of two arrays that map the number
* 1..7 to the English day of the week abbreviations
* Sun..Sat. No closures array is given; this is the same as
* specifying all closures to be FALSE.
{1,2,3,4,5,6,7},
* {"Sun","Mon","Tue","Wed","Thur","Fri","Sat"}
*
* Here is an example that maps the ranges [-Inf, 1), [1, 1], and (1, * +Inf] to three strings. That is, the number line is split into three * ranges: x < 1.0, x = 1.0, and x > 1.0.
* * {0, 1, 1},
* {FALSE, FALSE, TRUE},
* {"no files", "one file", "many files"}
*
* Here is a simple example that shows formatting and parsing:
* * \code * #includeHere is a more complex example using a ChoiceFormat
* constructed from a pattern together with a
* MessageFormat.
User subclasses are not supported. While clients may write * subclasses, such code will not necessarily work and will not be * guaranteed to work stably from release to release. */ class U_I18N_API ChoiceFormat: public NumberFormat { public: /** * Construct a new ChoiceFormat with the limits and the corresponding formats * based on the pattern. * * @param pattern Pattern used to construct object. * @param status Output param to receive success code. If the * pattern cannot be parsed, set to failure code. * @stable ICU 2.0 */ ChoiceFormat(const UnicodeString& pattern, UErrorCode& status); /** * Construct a new ChoiceFormat with the given limits and formats. Copy * the limits and formats instead of adopting them. * * @param limits Array of limit values. * @param formats Array of formats. * @param count Size of 'limits' and 'formats' arrays. * @stable ICU 2.0 */ ChoiceFormat(const double* limits, const UnicodeString* formats, int32_t count ); /** * Construct a new ChoiceFormat with the given limits and formats. * Copy the limits and formats (instead of adopting them). By * default, each limit in the array specifies the inclusive lower * bound of its range, and the exclusive upper bound of the previous * range. However, if the isLimitOpen element corresponding to a * limit is TRUE, then the limit is the exclusive lower bound of its * range, and the inclusive upper bound of the previous range. * @param limits Array of limit values * @param closures Array of booleans specifying whether each * element of 'limits' is open or closed. If FALSE, then the * corresponding limit is a member of the range above it. If TRUE, * then the limit belongs to the range below it. * @param formats Array of formats * @param count Size of 'limits', 'closures', and 'formats' arrays * @stable ICU 2.4 */ ChoiceFormat(const double* limits, const UBool* closures, const UnicodeString* formats, int32_t count); /** * Copy constructor. * * @param that ChoiceFormat object to be copied from * @stable ICU 2.0 */ ChoiceFormat(const ChoiceFormat& that); /** * Assignment operator. * * @param that ChoiceFormat object to be copied * @stable ICU 2.0 */ const ChoiceFormat& operator=(const ChoiceFormat& that); /** * Destructor. * @stable ICU 2.0 */ virtual ~ChoiceFormat(); /** * Clone this Format object polymorphically. The caller owns the * result and should delete it when done. * * @return a copy of this object * @stable ICU 2.0 */ virtual Format* clone(void) const; /** * Return true if the given Format objects are semantically equal. * Objects of different subclasses are considered unequal. * * @param other ChoiceFormat object to be compared * @return true if other is the same as this. * @stable ICU 2.0 */ virtual UBool operator==(const Format& other) const; /** * Sets the pattern. * @param pattern The pattern to be applied. * @param status Output param set to success/failure code on * exit. If the pattern is invalid, this will be * set to a failure result. * @stable ICU 2.0 */ virtual void applyPattern(const UnicodeString& pattern, UErrorCode& status); /** * Sets the pattern. * @param pattern The pattern to be applied. * @param parseError Struct to recieve information on position * of error if an error is encountered * @param status Output param set to success/failure code on * exit. If the pattern is invalid, this will be * set to a failure result. * @stable ICU 2.0 */ virtual void applyPattern(const UnicodeString& pattern, UParseError& parseError, UErrorCode& status); /** * Gets the pattern. * * @param pattern Output param which will recieve the pattern * Previous contents are deleted. * @return A reference to 'pattern' * @stable ICU 2.0 */ virtual UnicodeString& toPattern(UnicodeString &pattern) const; /** * Set the choices to be used in formatting. * * @param limitsToCopy Contains the top value that you want * parsed with that format,and should be in * ascending sorted order. When formatting X, * the choice will be the i, where limit[i] * <= X < limit[i+1]. * @param formatsToCopy The format strings you want to use for each limit. * @param count The size of the above arrays. * @stable ICU 2.0 */ virtual void setChoices(const double* limitsToCopy, const UnicodeString* formatsToCopy, int32_t count ); /** * Set the choices to be used in formatting. See class description * for documenatation of the limits, closures, and formats arrays. * @param limits Array of limits * @param closures Array of limit booleans * @param formats Array of format string * @param count The size of the above arrays * @stable ICU 2.4 */ virtual void setChoices(const double* limits, const UBool* closures, const UnicodeString* formats, int32_t count); /** * Get the limits passed in the constructor. * * @param count The size of the limits arrays * @return the limits. * @stable ICU 2.0 */ virtual const double* getLimits(int32_t& count) const; /** * Get the limit booleans passed in the constructor. The caller * must not delete the result. * * @param count The size of the arrays * @return the closures * @stable ICU 2.4 */ virtual const UBool* getClosures(int32_t& count) const; /** * Get the formats passed in the constructor. * * @param count The size of the arrays * @return the formats. * @stable ICU 2.0 */ virtual const UnicodeString* getFormats(int32_t& count) const; /** * Format a double or long number using this object's choices. * * @param number The value to be formatted. * @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. * @return Reference to 'appendTo' parameter. * @stable ICU 2.0 */ virtual UnicodeString& format(double number, UnicodeString& appendTo, FieldPosition& pos) const; /** * Format a int_32t number using this object's choices. * * @param number The value to be formatted. * @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. * @return Reference to 'appendTo' parameter. * @stable ICU 2.0 */ virtual UnicodeString& format(int32_t number, UnicodeString& appendTo, FieldPosition& pos) const; /** * Format an int64_t number using this object's choices. * * @param number The value to be formatted. * @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. * @return Reference to 'appendTo' parameter. * @stable ICU 2.8 */ virtual UnicodeString& format(int64_t number, UnicodeString& appendTo, FieldPosition& pos) const; /** * Format an array of objects using this object's choices. * * @param objs The array of objects to be formatted. * @param cnt The size of objs. * @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 success Output param set to success/failure code on * exit. * @return Reference to 'appendTo' parameter. * @stable ICU 2.0 */ virtual UnicodeString& format(const Formattable* objs, int32_t cnt, UnicodeString& appendTo, FieldPosition& pos, UErrorCode& success) const; /** * Format an object using this object's choices. * * * @param obj The object to be formatted. * @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. * @return Reference to 'appendTo' parameter. * @stable ICU 2.0 */ virtual UnicodeString& format(const Formattable& obj, UnicodeString& appendTo, FieldPosition& pos, UErrorCode& status) const; /** * Redeclared NumberFormat method. * * @param obj The object to be formatted. * @param appendTo Output parameter to receive result. * Result is appended to existing contents. * @param status Output param set to success/failure code on * exit. * @return Reference to 'appendTo' parameter. * @stable ICU 2.0 */ UnicodeString& format(const Formattable& obj, UnicodeString& appendTo, UErrorCode& status) const; /** * Redeclared NumberFormat method. * Format a double number. These methods call the NumberFormat * pure virtual format() methods with the default FieldPosition. * * @param number The value to be formatted. * @param appendTo Output parameter to receive result. * Result is appended to existing contents. * @return Reference to 'appendTo' parameter. * @stable ICU 2.0 */ UnicodeString& format( double number, UnicodeString& appendTo) const; /** * Redeclared NumberFormat method. * Format a long number. These methods call the NumberFormat * pure virtual format() methods with the default FieldPosition. * * @param number The value to be formatted. * @param appendTo Output parameter to receive result. * Result is appended to existing contents. * @return Reference to 'appendTo' parameter. * @stable ICU 2.0 */ UnicodeString& format( int32_t number, UnicodeString& appendTo) const; /** * Return a long if possible (e.g. within range LONG_MAX, * LONG_MAX], and with no decimals), otherwise a double. If * IntegerOnly is set, will stop at a decimal point (or equivalent; * e.g. for rational numbers "1 2/3", will stop after the 1). *
* If no object can be parsed, parsePosition is unchanged, and NULL is * returned. * * @param text The text to be parsed. * @param result Formattable to be set to the parse result. * If parse fails, return contents are undefined. * @param parsePosition The position to start parsing at on input. * On output, moved to after the last successfully * parse character. On parse failure, does not change. * @see NumberFormat::isParseIntegerOnly * @stable ICU 2.0 */ virtual void parse(const UnicodeString& text, Formattable& result, ParsePosition& parsePosition) const; /** * Return a long if possible (e.g. within range LONG_MAX, * LONG_MAX], and with no decimals), otherwise a double. If * IntegerOnly is set, will stop at a decimal point (or equivalent; * e.g. for rational numbers "1 2/3", will stop after the 1). *
* If no object can be parsed, parsePosition is unchanged, and NULL is * returned. * * @param text The text to be parsed. * @param result Formattable to be set to the parse result. * If parse fails, return contents are undefined. * @param status Output param with the formatted string. * @see NumberFormat::isParseIntegerOnly * @stable ICU 2.0 */ virtual void parse(const UnicodeString& text, Formattable& result, UErrorCode& status) const; public: /** * Returns a unique class ID POLYMORPHICALLY. Pure virtual override. * This method is to implement a simple version of RTTI, since not all * C++ compilers support genuine RTTI. Polymorphic operator==() and * clone() methods call this method. * * @return The class ID for this object. All objects of a * given class have the same class ID. Objects of * other classes have different class IDs. * @stable ICU 2.0 */ virtual UClassID getDynamicClassID(void) const; /** * Return the class ID for this class. This is useful only for * comparing to a return value from getDynamicClassID(). For example: *
* . Base* polymorphic_pointer = createPolymorphicObject();
* . if (polymorphic_pointer->getDynamicClassID() ==
* . Derived::getStaticClassID()) ...
*
* @return The class ID for all objects of this class.
* @stable ICU 2.0
*/
static UClassID U_EXPORT2 getStaticClassID(void);
private:
// static cache management (thread-safe)
// static NumberFormat* getNumberFormat(UErrorCode &status); // call this function to 'check out' a numberformat from the cache.
// static void releaseNumberFormat(NumberFormat *adopt); // call this function to 'return' the number format to the cache.
/**
* Converts a string to a double value using a default NumberFormat object
* which is static (shared by all ChoiceFormat instances).
* @param string the string to be converted with.
* @return the converted double number.
*/
static double stod(const UnicodeString& string);
/**
* Converts a double value to a string using a default NumberFormat object
* which is static (shared by all ChoiceFormat instances).
* @param value the double number to be converted with.
* @param string the result string.
* @return the converted string.
*/
static UnicodeString& dtos(double value, UnicodeString& string);
ChoiceFormat(); // default constructor not implemented
/**
* Construct a new ChoiceFormat with the limits and the corresponding formats
* based on the pattern.
*
* @param newPattern Pattern used to construct object.
* @param parseError Struct to recieve information on position
* of error if an error is encountered.
* @param status Output param to receive success code. If the
* pattern cannot be parsed, set to failure code.
* @stable ICU 2.0
*/
ChoiceFormat(const UnicodeString& newPattern,
UParseError& parseError,
UErrorCode& status);
friend class MessageFormat;
/**
* Each ChoiceFormat divides the range -Inf..+Inf into fCount
* intervals. The intervals are:
*
* 0: fChoiceLimits[0]..fChoiceLimits[1]
* 1: fChoiceLimits[1]..fChoiceLimits[2]
* ...
* fCount-2: fChoiceLimits[fCount-2]..fChoiceLimits[fCount-1]
* fCount-1: fChoiceLimits[fCount-1]..+Inf
*
* Interval 0 is special; during formatting (mapping numbers to
* strings), it also contains all numbers less than
* fChoiceLimits[0], as well as NaN values.
*
* Interval i maps to and from string fChoiceFormats[i]. When
* parsing (mapping strings to numbers), then intervals map to
* their lower limit, that is, interval i maps to fChoiceLimit[i].
*
* The intervals may be closed, half open, or open. This affects
* formatting but does not affect parsing. Interval i is affected
* by fClosures[i] and fClosures[i+1]. If fClosures[i]
* is FALSE, then the value fChoiceLimits[i] is in interval i.
* That is, intervals i and i are:
*
* i-1: ... x < fChoiceLimits[i]
* i: fChoiceLimits[i] <= x ...
*
* If fClosures[i] is TRUE, then the value fChoiceLimits[i] is
* in interval i-1. That is, intervals i-1 and i are:
*
* i-1: ... x <= fChoiceLimits[i]
* i: fChoiceLimits[i] < x ...
*
* Because of the nature of interval 0, fClosures[0] has no
* effect.
*/
double* fChoiceLimits;
UBool* fClosures;
UnicodeString* fChoiceFormats;
int32_t fCount;
};
inline UnicodeString&
ChoiceFormat::format(const Formattable& obj,
UnicodeString& appendTo,
UErrorCode& status) const {
// Don't use Format:: - use immediate base class only,
// in case immediate base modifies behavior later.
return NumberFormat::format(obj, appendTo, status);
}
inline UnicodeString&
ChoiceFormat::format(double number,
UnicodeString& appendTo) const {
return NumberFormat::format(number, appendTo);
}
inline UnicodeString&
ChoiceFormat::format(int32_t number,
UnicodeString& appendTo) const {
return NumberFormat::format(number, appendTo);
}
U_NAMESPACE_END
#endif /* #if !UCONFIG_NO_FORMATTING */
#endif // _CHOICFMT
//eof