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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) 2015, International Business Machines Corporation and         *
      6 * others. All Rights Reserved.                                                *
      7 *******************************************************************************
      8 */
      9 
     10 #ifndef VALUEFORMATTER_H
     11 #define VALUEFORMATTER_H
     12 
     13 #if !UCONFIG_NO_FORMATTING
     14 
     15 #include "unicode/uobject.h"
     16 #include "unicode/utypes.h"
     17 
     18 
     19 
     20 U_NAMESPACE_BEGIN
     21 
     22 class UnicodeString;
     23 class DigitList;
     24 class FieldPositionHandler;
     25 class DigitGrouping;
     26 class PluralRules;
     27 class FixedPrecision;
     28 class DigitFormatter;
     29 class DigitFormatterOptions;
     30 class ScientificPrecision;
     31 class SciFormatterOptions;
     32 class FixedDecimal;
     33 class VisibleDigitsWithExponent;
     34 
     35 
     36 /**
     37  * A closure around rounding and formatting a value. As these instances are
     38  * designed to be short lived (they only exist while formatting a value), they
     39  * do not own their own attributes. Rather the caller maintains ownership of
     40  * all attributes. A caller first calls a prepareXXX method on an instance
     41  * to share its data before using that instance. Using an
     42  * instance without first calling a prepareXXX method results in an
     43  * assertion error and a program crash.
     44  */
     45 class U_I18N_API ValueFormatter : public UObject {
     46 public:
     47     ValueFormatter() : fType(kFormatTypeCount) {
     48     }
     49 
     50     virtual ~ValueFormatter();
     51 
     52     /**
     53      * This function is here only to support the protected round() method
     54      * in DecimalFormat. It serves no ther purpose than that.
     55      *
     56      * @param value this value is rounded in place.
     57      * @param status any error returned here.
     58      */
     59     DigitList &round(DigitList &value, UErrorCode &status) const;
     60 
     61     /**
     62      * Returns TRUE if the absolute value of value can be fast formatted
     63      * using ValueFormatter::formatInt32.
     64      */
     65     UBool isFastFormattable(int32_t value) const;
     66 
     67     /**
     68      * Converts value to a VisibleDigitsWithExponent.
     69      * Result may be fixed point or scientific.
     70      */
     71     VisibleDigitsWithExponent &toVisibleDigitsWithExponent(
     72             int64_t value,
     73             VisibleDigitsWithExponent &digits,
     74             UErrorCode &status) const;
     75 
     76     /**
     77      * Converts value to a VisibleDigitsWithExponent.
     78      * Result may be fixed point or scientific.
     79      */
     80     VisibleDigitsWithExponent &toVisibleDigitsWithExponent(
     81             DigitList &value,
     82             VisibleDigitsWithExponent &digits,
     83             UErrorCode &status) const;
     84 
     85     /**
     86      * formats positiveValue and appends to appendTo. Returns appendTo.
     87      * @param positiveValue If negative, no negative sign is formatted.
     88      * @param handler stores the field positions
     89      * @param appendTo formatted value appended here.
     90      */
     91     UnicodeString &format(
     92         const VisibleDigitsWithExponent &positiveValue,
     93         FieldPositionHandler &handler,
     94         UnicodeString &appendTo) const;
     95 
     96 
     97     /**
     98      * formats positiveValue and appends to appendTo. Returns appendTo.
     99      * value must be positive. Calling formatInt32 to format a value when
    100      * isFastFormattable indicates that the value cannot be fast formatted
    101      * results in undefined behavior.
    102      */
    103     UnicodeString &formatInt32(
    104         int32_t positiveValue,
    105         FieldPositionHandler &handler,
    106         UnicodeString &appendTo) const;
    107 
    108     /**
    109      * Returns the number of code points needed to format.
    110      * @param positiveValue if negative, the negative sign is not included
    111      *   in count.
    112      */
    113     int32_t countChar32(
    114             const VisibleDigitsWithExponent &positiveValue) const;
    115 
    116     /**
    117      * Prepares this instance for fixed decimal formatting.
    118      */
    119     void prepareFixedDecimalFormatting(
    120         const DigitFormatter &formatter,
    121         const DigitGrouping &grouping,
    122         const FixedPrecision &precision,
    123         const DigitFormatterOptions &options);
    124 
    125     /**
    126      * Prepares this instance for scientific formatting.
    127      */
    128     void prepareScientificFormatting(
    129         const DigitFormatter &formatter,
    130         const ScientificPrecision &precision,
    131         const SciFormatterOptions &options);
    132 
    133 private:
    134     ValueFormatter(const ValueFormatter &);
    135     ValueFormatter &operator=(const ValueFormatter &);
    136     enum FormatType {
    137         kFixedDecimal,
    138         kScientificNotation,
    139         kFormatTypeCount
    140     };
    141 
    142     FormatType fType;
    143 
    144     // for fixed decimal and scientific formatting
    145     const DigitFormatter *fDigitFormatter;
    146 
    147     // for fixed decimal formatting
    148     const FixedPrecision *fFixedPrecision;
    149     const DigitFormatterOptions *fFixedOptions;
    150     const DigitGrouping *fGrouping;
    151 
    152     // for scientific formatting
    153     const ScientificPrecision *fScientificPrecision;
    154     const SciFormatterOptions *fScientificOptions;
    155 };
    156 
    157 U_NAMESPACE_END
    158 
    159 #endif /* !UCONFIG_NO_FORMATTING */
    160 
    161 #endif /* VALUEFORMATTER_H */
    162