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      1 /*
      2 *******************************************************************************
      3 * Copyright (C) 2015, International Business Machines Corporation and         *
      4 * others. All Rights Reserved.                                                *
      5 *******************************************************************************
      6 */
      7 
      8 #ifndef VALUEFORMATTER_H
      9 #define VALUEFORMATTER_H
     10 
     11 #if !UCONFIG_NO_FORMATTING
     12 
     13 #include "unicode/uobject.h"
     14 #include "unicode/utypes.h"
     15 
     16 
     17 
     18 U_NAMESPACE_BEGIN
     19 
     20 class UnicodeString;
     21 class DigitList;
     22 class FieldPositionHandler;
     23 class DigitGrouping;
     24 class PluralRules;
     25 class FixedPrecision;
     26 class DigitFormatter;
     27 class DigitFormatterOptions;
     28 class ScientificPrecision;
     29 class SciFormatterOptions;
     30 class FixedDecimal;
     31 class VisibleDigitsWithExponent;
     32 
     33 
     34 /**
     35  * A closure around rounding and formatting a value. As these instances are
     36  * designed to be short lived (they only exist while formatting a value), they
     37  * do not own their own attributes. Rather the caller maintains ownership of
     38  * all attributes. A caller first calls a prepareXXX method on an instance
     39  * to share its data before using that instance. Using an
     40  * instance without first calling a prepareXXX method results in an
     41  * assertion error and a program crash.
     42  */
     43 class U_I18N_API ValueFormatter : public UObject {
     44 public:
     45     ValueFormatter() : fType(kFormatTypeCount) {
     46     }
     47 
     48     virtual ~ValueFormatter();
     49 
     50     /**
     51      * This function is here only to support the protected round() method
     52      * in DecimalFormat. It serves no ther purpose than that.
     53      *
     54      * @param value this value is rounded in place.
     55      * @param status any error returned here.
     56      */
     57     DigitList &round(DigitList &value, UErrorCode &status) const;
     58 
     59     /**
     60      * Returns TRUE if the absolute value of value can be fast formatted
     61      * using ValueFormatter::formatInt32.
     62      */
     63     UBool isFastFormattable(int32_t value) const;
     64 
     65     /**
     66      * Converts value to a VisibleDigitsWithExponent.
     67      * Result may be fixed point or scientific.
     68      */
     69     VisibleDigitsWithExponent &toVisibleDigitsWithExponent(
     70             int64_t value,
     71             VisibleDigitsWithExponent &digits,
     72             UErrorCode &status) const;
     73 
     74     /**
     75      * Converts value to a VisibleDigitsWithExponent.
     76      * Result may be fixed point or scientific.
     77      */
     78     VisibleDigitsWithExponent &toVisibleDigitsWithExponent(
     79             DigitList &value,
     80             VisibleDigitsWithExponent &digits,
     81             UErrorCode &status) const;
     82 
     83     /**
     84      * formats positiveValue and appends to appendTo. Returns appendTo.
     85      * @param positiveValue If negative, no negative sign is formatted.
     86      * @param handler stores the field positions
     87      * @param appendTo formatted value appended here.
     88      */
     89     UnicodeString &format(
     90         const VisibleDigitsWithExponent &positiveValue,
     91         FieldPositionHandler &handler,
     92         UnicodeString &appendTo) const;
     93 
     94 
     95     /**
     96      * formats positiveValue and appends to appendTo. Returns appendTo.
     97      * value must be positive. Calling formatInt32 to format a value when
     98      * isFastFormattable indicates that the value cannot be fast formatted
     99      * results in undefined behavior.
    100      */
    101     UnicodeString &formatInt32(
    102         int32_t positiveValue,
    103         FieldPositionHandler &handler,
    104         UnicodeString &appendTo) const;
    105 
    106     /**
    107      * Returns the number of code points needed to format.
    108      * @param positiveValue if negative, the negative sign is not included
    109      *   in count.
    110      */
    111     int32_t countChar32(
    112             const VisibleDigitsWithExponent &positiveValue) const;
    113 
    114     /**
    115      * Prepares this instance for fixed decimal formatting.
    116      */
    117     void prepareFixedDecimalFormatting(
    118         const DigitFormatter &formatter,
    119         const DigitGrouping &grouping,
    120         const FixedPrecision &precision,
    121         const DigitFormatterOptions &options);
    122 
    123     /**
    124      * Prepares this instance for scientific formatting.
    125      */
    126     void prepareScientificFormatting(
    127         const DigitFormatter &formatter,
    128         const ScientificPrecision &precision,
    129         const SciFormatterOptions &options);
    130 
    131 private:
    132     ValueFormatter(const ValueFormatter &);
    133     ValueFormatter &operator=(const ValueFormatter &);
    134     enum FormatType {
    135         kFixedDecimal,
    136         kScientificNotation,
    137         kFormatTypeCount
    138     };
    139 
    140     FormatType fType;
    141 
    142     // for fixed decimal and scientific formatting
    143     const DigitFormatter *fDigitFormatter;
    144 
    145     // for fixed decimal formatting
    146     const FixedPrecision *fFixedPrecision;
    147     const DigitFormatterOptions *fFixedOptions;
    148     const DigitGrouping *fGrouping;
    149 
    150     // for scientific formatting
    151     const ScientificPrecision *fScientificPrecision;
    152     const SciFormatterOptions *fScientificOptions;
    153 };
    154 
    155 U_NAMESPACE_END
    156 
    157 #endif /* !UCONFIG_NO_FORMATTING */
    158 
    159 #endif /* VALUEFORMATTER_H */
    160