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      1 /*
      2 ********************************************************************************
      3 *   Copyright (C) 1997-2015, International Business Machines
      4 *   Corporation and others.  All Rights Reserved.
      5 ********************************************************************************
      6 *
      7 * File DECIMFMT.H
      8 *
      9 * Modification History:
     10 *
     11 *   Date        Name        Description
     12 *   02/19/97    aliu        Converted from java.
     13 *   03/20/97    clhuang     Updated per C++ implementation.
     14 *   04/03/97    aliu        Rewrote parsing and formatting completely, and
     15 *                           cleaned up and debugged.  Actually works now.
     16 *   04/17/97    aliu        Changed DigitCount to int per code review.
     17 *   07/10/97    helena      Made ParsePosition a class and get rid of the function
     18 *                           hiding problems.
     19 *   09/09/97    aliu        Ported over support for exponential formats.
     20 *   07/20/98    stephen     Changed documentation
     21 *   01/30/13    emmons      Added Scaling methods
     22 ********************************************************************************
     23 */
     24 
     25 #ifndef DECIMFMT_H
     26 #define DECIMFMT_H
     27 
     28 #include "unicode/utypes.h"
     29 /**
     30  * \file
     31  * \brief C++ API: Formats decimal numbers.
     32  */
     33 
     34 #if !UCONFIG_NO_FORMATTING
     35 
     36 #include "unicode/dcfmtsym.h"
     37 #include "unicode/numfmt.h"
     38 #include "unicode/locid.h"
     39 #include "unicode/fpositer.h"
     40 #include "unicode/stringpiece.h"
     41 #include "unicode/curramt.h"
     42 #include "unicode/enumset.h"
     43 
     44 #ifndef U_HIDE_INTERNAL_API
     45 /**
     46  * \def UNUM_DECIMALFORMAT_INTERNAL_SIZE
     47  * @internal
     48  */
     49 #if UCONFIG_FORMAT_FASTPATHS_49
     50 #define UNUM_DECIMALFORMAT_INTERNAL_SIZE 16
     51 #endif
     52 #endif  /* U_HIDE_INTERNAL_API */
     53 
     54 U_NAMESPACE_BEGIN
     55 
     56 class DigitList;
     57 class ChoiceFormat;
     58 class CurrencyPluralInfo;
     59 class Hashtable;
     60 class UnicodeSet;
     61 class FieldPositionHandler;
     62 class DecimalFormatStaticSets;
     63 class FixedDecimal;
     64 class DecimalFormatImpl;
     65 class PluralRules;
     66 class VisibleDigitsWithExponent;
     67 
     68 // explicit template instantiation. see digitlst.h
     69 #if defined (_MSC_VER)
     70 template class U_I18N_API    EnumSet<UNumberFormatAttribute,
     71             UNUM_MAX_NONBOOLEAN_ATTRIBUTE+1,
     72             UNUM_LIMIT_BOOLEAN_ATTRIBUTE>;
     73 #endif
     74 
     75 /**
     76  * DecimalFormat is a concrete subclass of NumberFormat that formats decimal
     77  * numbers. It has a variety of features designed to make it possible to parse
     78  * and format numbers in any locale, including support for Western, Arabic, or
     79  * Indic digits.  It also supports different flavors of numbers, including
     80  * integers ("123"), fixed-point numbers ("123.4"), scientific notation
     81  * ("1.23E4"), percentages ("12%"), and currency amounts ("$123", "USD123",
     82  * "123 US dollars").  All of these flavors can be easily localized.
     83  *
     84  * <p>To obtain a NumberFormat for a specific locale (including the default
     85  * locale) call one of NumberFormat's factory methods such as
     86  * createInstance(). Do not call the DecimalFormat constructors directly, unless
     87  * you know what you are doing, since the NumberFormat factory methods may
     88  * return subclasses other than DecimalFormat.
     89  *
     90  * <p><strong>Example Usage</strong>
     91  *
     92  * \code
     93  *     // Normally we would have a GUI with a menu for this
     94  *     int32_t locCount;
     95  *     const Locale* locales = NumberFormat::getAvailableLocales(locCount);
     96  *
     97  *     double myNumber = -1234.56;
     98  *     UErrorCode success = U_ZERO_ERROR;
     99  *     NumberFormat* form;
    100  *
    101  *     // Print out a number with the localized number, currency and percent
    102  *     // format for each locale.
    103  *     UnicodeString countryName;
    104  *     UnicodeString displayName;
    105  *     UnicodeString str;
    106  *     UnicodeString pattern;
    107  *     Formattable fmtable;
    108  *     for (int32_t j = 0; j < 3; ++j) {
    109  *         cout << endl << "FORMAT " << j << endl;
    110  *         for (int32_t i = 0; i < locCount; ++i) {
    111  *             if (locales[i].getCountry(countryName).size() == 0) {
    112  *                 // skip language-only
    113  *                 continue;
    114  *             }
    115  *             switch (j) {
    116  *             case 0:
    117  *                 form = NumberFormat::createInstance(locales[i], success ); break;
    118  *             case 1:
    119  *                 form = NumberFormat::createCurrencyInstance(locales[i], success ); break;
    120  *             default:
    121  *                 form = NumberFormat::createPercentInstance(locales[i], success ); break;
    122  *             }
    123  *             if (form) {
    124  *                 str.remove();
    125  *                 pattern = ((DecimalFormat*)form)->toPattern(pattern);
    126  *                 cout << locales[i].getDisplayName(displayName) << ": " << pattern;
    127  *                 cout << "  ->  " << form->format(myNumber,str) << endl;
    128  *                 form->parse(form->format(myNumber,str), fmtable, success);
    129  *                 delete form;
    130  *             }
    131  *         }
    132  *     }
    133  * \endcode
    134  * <P>
    135  * Another example use createInstance(style)
    136  * <P>
    137  * <pre>
    138  * <strong>// Print out a number using the localized number, currency,
    139  * // percent, scientific, integer, iso currency, and plural currency
    140  * // format for each locale</strong>
    141  * Locale* locale = new Locale("en", "US");
    142  * double myNumber = 1234.56;
    143  * UErrorCode success = U_ZERO_ERROR;
    144  * UnicodeString str;
    145  * Formattable fmtable;
    146  * for (int j=NumberFormat::kNumberStyle;
    147  *      j<=NumberFormat::kPluralCurrencyStyle;
    148  *      ++j) {
    149  *     NumberFormat* format = NumberFormat::createInstance(locale, j, success);
    150  *     str.remove();
    151  *     cout << "format result " << form->format(myNumber, str) << endl;
    152  *     format->parse(form->format(myNumber, str), fmtable, success);
    153  * }</pre>
    154  *
    155  *
    156  * <p><strong>Patterns</strong>
    157  *
    158  * <p>A DecimalFormat consists of a <em>pattern</em> and a set of
    159  * <em>symbols</em>.  The pattern may be set directly using
    160  * applyPattern(), or indirectly using other API methods which
    161  * manipulate aspects of the pattern, such as the minimum number of integer
    162  * digits.  The symbols are stored in a DecimalFormatSymbols
    163  * object.  When using the NumberFormat factory methods, the
    164  * pattern and symbols are read from ICU's locale data.
    165  *
    166  * <p><strong>Special Pattern Characters</strong>
    167  *
    168  * <p>Many characters in a pattern are taken literally; they are matched during
    169  * parsing and output unchanged during formatting.  Special characters, on the
    170  * other hand, stand for other characters, strings, or classes of characters.
    171  * For example, the '#' character is replaced by a localized digit.  Often the
    172  * replacement character is the same as the pattern character; in the U.S. locale,
    173  * the ',' grouping character is replaced by ','.  However, the replacement is
    174  * still happening, and if the symbols are modified, the grouping character
    175  * changes.  Some special characters affect the behavior of the formatter by
    176  * their presence; for example, if the percent character is seen, then the
    177  * value is multiplied by 100 before being displayed.
    178  *
    179  * <p>To insert a special character in a pattern as a literal, that is, without
    180  * any special meaning, the character must be quoted.  There are some exceptions to
    181  * this which are noted below.
    182  *
    183  * <p>The characters listed here are used in non-localized patterns.  Localized
    184  * patterns use the corresponding characters taken from this formatter's
    185  * DecimalFormatSymbols object instead, and these characters lose
    186  * their special status.  Two exceptions are the currency sign and quote, which
    187  * are not localized.
    188  *
    189  * <table border=0 cellspacing=3 cellpadding=0>
    190  *   <tr bgcolor="#ccccff">
    191  *     <td align=left><strong>Symbol</strong>
    192  *     <td align=left><strong>Location</strong>
    193  *     <td align=left><strong>Localized?</strong>
    194  *     <td align=left><strong>Meaning</strong>
    195  *   <tr valign=top>
    196  *     <td><code>0</code>
    197  *     <td>Number
    198  *     <td>Yes
    199  *     <td>Digit
    200  *   <tr valign=top bgcolor="#eeeeff">
    201  *     <td><code>1-9</code>
    202  *     <td>Number
    203  *     <td>Yes
    204  *     <td>'1' through '9' indicate rounding.
    205  *   <tr valign=top>
    206  *     <td><code>\htmlonly&#x40;\endhtmlonly</code> <!--doxygen doesn't like @-->
    207  *     <td>Number
    208  *     <td>No
    209  *     <td>Significant digit
    210  *   <tr valign=top bgcolor="#eeeeff">
    211  *     <td><code>#</code>
    212  *     <td>Number
    213  *     <td>Yes
    214  *     <td>Digit, zero shows as absent
    215  *   <tr valign=top>
    216  *     <td><code>.</code>
    217  *     <td>Number
    218  *     <td>Yes
    219  *     <td>Decimal separator or monetary decimal separator
    220  *   <tr valign=top bgcolor="#eeeeff">
    221  *     <td><code>-</code>
    222  *     <td>Number
    223  *     <td>Yes
    224  *     <td>Minus sign
    225  *   <tr valign=top>
    226  *     <td><code>,</code>
    227  *     <td>Number
    228  *     <td>Yes
    229  *     <td>Grouping separator
    230  *   <tr valign=top bgcolor="#eeeeff">
    231  *     <td><code>E</code>
    232  *     <td>Number
    233  *     <td>Yes
    234  *     <td>Separates mantissa and exponent in scientific notation.
    235  *         <em>Need not be quoted in prefix or suffix.</em>
    236  *   <tr valign=top>
    237  *     <td><code>+</code>
    238  *     <td>Exponent
    239  *     <td>Yes
    240  *     <td>Prefix positive exponents with localized plus sign.
    241  *         <em>Need not be quoted in prefix or suffix.</em>
    242  *   <tr valign=top bgcolor="#eeeeff">
    243  *     <td><code>;</code>
    244  *     <td>Subpattern boundary
    245  *     <td>Yes
    246  *     <td>Separates positive and negative subpatterns
    247  *   <tr valign=top>
    248  *     <td><code>\%</code>
    249  *     <td>Prefix or suffix
    250  *     <td>Yes
    251  *     <td>Multiply by 100 and show as percentage
    252  *   <tr valign=top bgcolor="#eeeeff">
    253  *     <td><code>\\u2030</code>
    254  *     <td>Prefix or suffix
    255  *     <td>Yes
    256  *     <td>Multiply by 1000 and show as per mille
    257  *   <tr valign=top>
    258  *     <td><code>\htmlonly&curren;\endhtmlonly</code> (<code>\\u00A4</code>)
    259  *     <td>Prefix or suffix
    260  *     <td>No
    261  *     <td>Currency sign, replaced by currency symbol.  If
    262  *         doubled, replaced by international currency symbol.
    263  *         If tripled, replaced by currency plural names, for example,
    264  *         "US dollar" or "US dollars" for America.
    265  *         If present in a pattern, the monetary decimal separator
    266  *         is used instead of the decimal separator.
    267  *   <tr valign=top bgcolor="#eeeeff">
    268  *     <td><code>'</code>
    269  *     <td>Prefix or suffix
    270  *     <td>No
    271  *     <td>Used to quote special characters in a prefix or suffix,
    272  *         for example, <code>"'#'#"</code> formats 123 to
    273  *         <code>"#123"</code>.  To create a single quote
    274  *         itself, use two in a row: <code>"# o''clock"</code>.
    275  *   <tr valign=top>
    276  *     <td><code>*</code>
    277  *     <td>Prefix or suffix boundary
    278  *     <td>Yes
    279  *     <td>Pad escape, precedes pad character
    280  * </table>
    281  *
    282  * <p>A DecimalFormat pattern contains a postive and negative
    283  * subpattern, for example, "#,##0.00;(#,##0.00)".  Each subpattern has a
    284  * prefix, a numeric part, and a suffix.  If there is no explicit negative
    285  * subpattern, the negative subpattern is the localized minus sign prefixed to the
    286  * positive subpattern. That is, "0.00" alone is equivalent to "0.00;-0.00".  If there
    287  * is an explicit negative subpattern, it serves only to specify the negative
    288  * prefix and suffix; the number of digits, minimal digits, and other
    289  * characteristics are ignored in the negative subpattern. That means that
    290  * "#,##0.0#;(#)" has precisely the same result as "#,##0.0#;(#,##0.0#)".
    291  *
    292  * <p>The prefixes, suffixes, and various symbols used for infinity, digits,
    293  * thousands separators, decimal separators, etc. may be set to arbitrary
    294  * values, and they will appear properly during formatting.  However, care must
    295  * be taken that the symbols and strings do not conflict, or parsing will be
    296  * unreliable.  For example, either the positive and negative prefixes or the
    297  * suffixes must be distinct for parse() to be able
    298  * to distinguish positive from negative values.  Another example is that the
    299  * decimal separator and thousands separator should be distinct characters, or
    300  * parsing will be impossible.
    301  *
    302  * <p>The <em>grouping separator</em> is a character that separates clusters of
    303  * integer digits to make large numbers more legible.  It commonly used for
    304  * thousands, but in some locales it separates ten-thousands.  The <em>grouping
    305  * size</em> is the number of digits between the grouping separators, such as 3
    306  * for "100,000,000" or 4 for "1 0000 0000". There are actually two different
    307  * grouping sizes: One used for the least significant integer digits, the
    308  * <em>primary grouping size</em>, and one used for all others, the
    309  * <em>secondary grouping size</em>.  In most locales these are the same, but
    310  * sometimes they are different. For example, if the primary grouping interval
    311  * is 3, and the secondary is 2, then this corresponds to the pattern
    312  * "#,##,##0", and the number 123456789 is formatted as "12,34,56,789".  If a
    313  * pattern contains multiple grouping separators, the interval between the last
    314  * one and the end of the integer defines the primary grouping size, and the
    315  * interval between the last two defines the secondary grouping size. All others
    316  * are ignored, so "#,##,###,####" == "###,###,####" == "##,#,###,####".
    317  *
    318  * <p>Illegal patterns, such as "#.#.#" or "#.###,###", will cause
    319  * DecimalFormat to set a failing UErrorCode.
    320  *
    321  * <p><strong>Pattern BNF</strong>
    322  *
    323  * <pre>
    324  * pattern    := subpattern (';' subpattern)?
    325  * subpattern := prefix? number exponent? suffix?
    326  * number     := (integer ('.' fraction)?) | sigDigits
    327  * prefix     := '\\u0000'..'\\uFFFD' - specialCharacters
    328  * suffix     := '\\u0000'..'\\uFFFD' - specialCharacters
    329  * integer    := '#'* '0'* '0'
    330  * fraction   := '0'* '#'*
    331  * sigDigits  := '#'* '@' '@'* '#'*
    332  * exponent   := 'E' '+'? '0'* '0'
    333  * padSpec    := '*' padChar
    334  * padChar    := '\\u0000'..'\\uFFFD' - quote
    335  * &nbsp;
    336  * Notation:
    337  *   X*       0 or more instances of X
    338  *   X?       0 or 1 instances of X
    339  *   X|Y      either X or Y
    340  *   C..D     any character from C up to D, inclusive
    341  *   S-T      characters in S, except those in T
    342  * </pre>
    343  * The first subpattern is for positive numbers. The second (optional)
    344  * subpattern is for negative numbers.
    345  *
    346  * <p>Not indicated in the BNF syntax above:
    347  *
    348  * <ul><li>The grouping separator ',' can occur inside the integer and
    349  * sigDigits elements, between any two pattern characters of that
    350  * element, as long as the integer or sigDigits element is not
    351  * followed by the exponent element.
    352  *
    353  * <li>Two grouping intervals are recognized: That between the
    354  *     decimal point and the first grouping symbol, and that
    355  *     between the first and second grouping symbols. These
    356  *     intervals are identical in most locales, but in some
    357  *     locales they differ. For example, the pattern
    358  *     &quot;#,##,###&quot; formats the number 123456789 as
    359  *     &quot;12,34,56,789&quot;.</li>
    360  *
    361  * <li>The pad specifier <code>padSpec</code> may appear before the prefix,
    362  * after the prefix, before the suffix, after the suffix, or not at all.
    363  *
    364  * <li>In place of '0', the digits '1' through '9' may be used to
    365  * indicate a rounding increment.
    366  * </ul>
    367  *
    368  * <p><strong>Parsing</strong>
    369  *
    370  * <p>DecimalFormat parses all Unicode characters that represent
    371  * decimal digits, as defined by u_charDigitValue().  In addition,
    372  * DecimalFormat also recognizes as digits the ten consecutive
    373  * characters starting with the localized zero digit defined in the
    374  * DecimalFormatSymbols object.  During formatting, the
    375  * DecimalFormatSymbols-based digits are output.
    376  *
    377  * <p>During parsing, grouping separators are ignored if in lenient mode;
    378  * otherwise, if present, they must be in appropriate positions.
    379  *
    380  * <p>For currency parsing, the formatter is able to parse every currency
    381  * style formats no matter which style the formatter is constructed with.
    382  * For example, a formatter instance gotten from
    383  * NumberFormat.getInstance(ULocale, NumberFormat.CURRENCYSTYLE) can parse
    384  * formats such as "USD1.00" and "3.00 US dollars".
    385  *
    386  * <p>If parse(UnicodeString&,Formattable&,ParsePosition&)
    387  * fails to parse a string, it leaves the parse position unchanged.
    388  * The convenience method parse(UnicodeString&,Formattable&,UErrorCode&)
    389  * indicates parse failure by setting a failing
    390  * UErrorCode.
    391  *
    392  * <p><strong>Formatting</strong>
    393  *
    394  * <p>Formatting is guided by several parameters, all of which can be
    395  * specified either using a pattern or using the API.  The following
    396  * description applies to formats that do not use <a href="#sci">scientific
    397  * notation</a> or <a href="#sigdig">significant digits</a>.
    398  *
    399  * <ul><li>If the number of actual integer digits exceeds the
    400  * <em>maximum integer digits</em>, then only the least significant
    401  * digits are shown.  For example, 1997 is formatted as "97" if the
    402  * maximum integer digits is set to 2.
    403  *
    404  * <li>If the number of actual integer digits is less than the
    405  * <em>minimum integer digits</em>, then leading zeros are added.  For
    406  * example, 1997 is formatted as "01997" if the minimum integer digits
    407  * is set to 5.
    408  *
    409  * <li>If the number of actual fraction digits exceeds the <em>maximum
    410  * fraction digits</em>, then rounding is performed to the
    411  * maximum fraction digits.  For example, 0.125 is formatted as "0.12"
    412  * if the maximum fraction digits is 2.  This behavior can be changed
    413  * by specifying a rounding increment and/or a rounding mode.
    414  *
    415  * <li>If the number of actual fraction digits is less than the
    416  * <em>minimum fraction digits</em>, then trailing zeros are added.
    417  * For example, 0.125 is formatted as "0.1250" if the mimimum fraction
    418  * digits is set to 4.
    419  *
    420  * <li>Trailing fractional zeros are not displayed if they occur
    421  * <em>j</em> positions after the decimal, where <em>j</em> is less
    422  * than the maximum fraction digits. For example, 0.10004 is
    423  * formatted as "0.1" if the maximum fraction digits is four or less.
    424  * </ul>
    425  *
    426  * <p><strong>Special Values</strong>
    427  *
    428  * <p><code>NaN</code> is represented as a single character, typically
    429  * <code>\\uFFFD</code>.  This character is determined by the
    430  * DecimalFormatSymbols object.  This is the only value for which
    431  * the prefixes and suffixes are not used.
    432  *
    433  * <p>Infinity is represented as a single character, typically
    434  * <code>\\u221E</code>, with the positive or negative prefixes and suffixes
    435  * applied.  The infinity character is determined by the
    436  * DecimalFormatSymbols object.
    437  *
    438  * <a name="sci"><strong>Scientific Notation</strong></a>
    439  *
    440  * <p>Numbers in scientific notation are expressed as the product of a mantissa
    441  * and a power of ten, for example, 1234 can be expressed as 1.234 x 10<sup>3</sup>. The
    442  * mantissa is typically in the half-open interval [1.0, 10.0) or sometimes [0.0, 1.0),
    443  * but it need not be.  DecimalFormat supports arbitrary mantissas.
    444  * DecimalFormat can be instructed to use scientific
    445  * notation through the API or through the pattern.  In a pattern, the exponent
    446  * character immediately followed by one or more digit characters indicates
    447  * scientific notation.  Example: "0.###E0" formats the number 1234 as
    448  * "1.234E3".
    449  *
    450  * <ul>
    451  * <li>The number of digit characters after the exponent character gives the
    452  * minimum exponent digit count.  There is no maximum.  Negative exponents are
    453  * formatted using the localized minus sign, <em>not</em> the prefix and suffix
    454  * from the pattern.  This allows patterns such as "0.###E0 m/s".  To prefix
    455  * positive exponents with a localized plus sign, specify '+' between the
    456  * exponent and the digits: "0.###E+0" will produce formats "1E+1", "1E+0",
    457  * "1E-1", etc.  (In localized patterns, use the localized plus sign rather than
    458  * '+'.)
    459  *
    460  * <li>The minimum number of integer digits is achieved by adjusting the
    461  * exponent.  Example: 0.00123 formatted with "00.###E0" yields "12.3E-4".  This
    462  * only happens if there is no maximum number of integer digits.  If there is a
    463  * maximum, then the minimum number of integer digits is fixed at one.
    464  *
    465  * <li>The maximum number of integer digits, if present, specifies the exponent
    466  * grouping.  The most common use of this is to generate <em>engineering
    467  * notation</em>, in which the exponent is a multiple of three, e.g.,
    468  * "##0.###E0".  The number 12345 is formatted using "##0.####E0" as "12.345E3".
    469  *
    470  * <li>When using scientific notation, the formatter controls the
    471  * digit counts using significant digits logic.  The maximum number of
    472  * significant digits limits the total number of integer and fraction
    473  * digits that will be shown in the mantissa; it does not affect
    474  * parsing.  For example, 12345 formatted with "##0.##E0" is "12.3E3".
    475  * See the section on significant digits for more details.
    476  *
    477  * <li>The number of significant digits shown is determined as
    478  * follows: If areSignificantDigitsUsed() returns false, then the
    479  * minimum number of significant digits shown is one, and the maximum
    480  * number of significant digits shown is the sum of the <em>minimum
    481  * integer</em> and <em>maximum fraction</em> digits, and is
    482  * unaffected by the maximum integer digits.  If this sum is zero,
    483  * then all significant digits are shown.  If
    484  * areSignificantDigitsUsed() returns true, then the significant digit
    485  * counts are specified by getMinimumSignificantDigits() and
    486  * getMaximumSignificantDigits().  In this case, the number of
    487  * integer digits is fixed at one, and there is no exponent grouping.
    488  *
    489  * <li>Exponential patterns may not contain grouping separators.
    490  * </ul>
    491  *
    492  * <a name="sigdig"><strong>Significant Digits</strong></a>
    493  *
    494  * <code>DecimalFormat</code> has two ways of controlling how many
    495  * digits are shows: (a) significant digits counts, or (b) integer and
    496  * fraction digit counts.  Integer and fraction digit counts are
    497  * described above.  When a formatter is using significant digits
    498  * counts, the number of integer and fraction digits is not specified
    499  * directly, and the formatter settings for these counts are ignored.
    500  * Instead, the formatter uses however many integer and fraction
    501  * digits are required to display the specified number of significant
    502  * digits.  Examples:
    503  *
    504  * <table border=0 cellspacing=3 cellpadding=0>
    505  *   <tr bgcolor="#ccccff">
    506  *     <td align=left>Pattern
    507  *     <td align=left>Minimum significant digits
    508  *     <td align=left>Maximum significant digits
    509  *     <td align=left>Number
    510  *     <td align=left>Output of format()
    511  *   <tr valign=top>
    512  *     <td><code>\@\@\@</code>
    513  *     <td>3
    514  *     <td>3
    515  *     <td>12345
    516  *     <td><code>12300</code>
    517  *   <tr valign=top bgcolor="#eeeeff">
    518  *     <td><code>\@\@\@</code>
    519  *     <td>3
    520  *     <td>3
    521  *     <td>0.12345
    522  *     <td><code>0.123</code>
    523  *   <tr valign=top>
    524  *     <td><code>\@\@##</code>
    525  *     <td>2
    526  *     <td>4
    527  *     <td>3.14159
    528  *     <td><code>3.142</code>
    529  *   <tr valign=top bgcolor="#eeeeff">
    530  *     <td><code>\@\@##</code>
    531  *     <td>2
    532  *     <td>4
    533  *     <td>1.23004
    534  *     <td><code>1.23</code>
    535  * </table>
    536  *
    537  * <ul>
    538  * <li>Significant digit counts may be expressed using patterns that
    539  * specify a minimum and maximum number of significant digits.  These
    540  * are indicated by the <code>'@'</code> and <code>'#'</code>
    541  * characters.  The minimum number of significant digits is the number
    542  * of <code>'@'</code> characters.  The maximum number of significant
    543  * digits is the number of <code>'@'</code> characters plus the number
    544  * of <code>'#'</code> characters following on the right.  For
    545  * example, the pattern <code>"@@@"</code> indicates exactly 3
    546  * significant digits.  The pattern <code>"@##"</code> indicates from
    547  * 1 to 3 significant digits.  Trailing zero digits to the right of
    548  * the decimal separator are suppressed after the minimum number of
    549  * significant digits have been shown.  For example, the pattern
    550  * <code>"@##"</code> formats the number 0.1203 as
    551  * <code>"0.12"</code>.
    552  *
    553  * <li>If a pattern uses significant digits, it may not contain a
    554  * decimal separator, nor the <code>'0'</code> pattern character.
    555  * Patterns such as <code>"@00"</code> or <code>"@.###"</code> are
    556  * disallowed.
    557  *
    558  * <li>Any number of <code>'#'</code> characters may be prepended to
    559  * the left of the leftmost <code>'@'</code> character.  These have no
    560  * effect on the minimum and maximum significant digits counts, but
    561  * may be used to position grouping separators.  For example,
    562  * <code>"#,#@#"</code> indicates a minimum of one significant digits,
    563  * a maximum of two significant digits, and a grouping size of three.
    564  *
    565  * <li>In order to enable significant digits formatting, use a pattern
    566  * containing the <code>'@'</code> pattern character.  Alternatively,
    567  * call setSignificantDigitsUsed(TRUE).
    568  *
    569  * <li>In order to disable significant digits formatting, use a
    570  * pattern that does not contain the <code>'@'</code> pattern
    571  * character. Alternatively, call setSignificantDigitsUsed(FALSE).
    572  *
    573  * <li>The number of significant digits has no effect on parsing.
    574  *
    575  * <li>Significant digits may be used together with exponential notation. Such
    576  * patterns are equivalent to a normal exponential pattern with a minimum and
    577  * maximum integer digit count of one, a minimum fraction digit count of
    578  * <code>getMinimumSignificantDigits() - 1</code>, and a maximum fraction digit
    579  * count of <code>getMaximumSignificantDigits() - 1</code>. For example, the
    580  * pattern <code>"@@###E0"</code> is equivalent to <code>"0.0###E0"</code>.
    581  *
    582  * <li>If signficant digits are in use, then the integer and fraction
    583  * digit counts, as set via the API, are ignored.  If significant
    584  * digits are not in use, then the signficant digit counts, as set via
    585  * the API, are ignored.
    586  *
    587  * </ul>
    588  *
    589  * <p><strong>Padding</strong>
    590  *
    591  * <p>DecimalFormat supports padding the result of
    592  * format() to a specific width.  Padding may be specified either
    593  * through the API or through the pattern syntax.  In a pattern the pad escape
    594  * character, followed by a single pad character, causes padding to be parsed
    595  * and formatted.  The pad escape character is '*' in unlocalized patterns, and
    596  * can be localized using DecimalFormatSymbols::setSymbol() with a
    597  * DecimalFormatSymbols::kPadEscapeSymbol
    598  * selector.  For example, <code>"$*x#,##0.00"</code> formats 123 to
    599  * <code>"$xx123.00"</code>, and 1234 to <code>"$1,234.00"</code>.
    600  *
    601  * <ul>
    602  * <li>When padding is in effect, the width of the positive subpattern,
    603  * including prefix and suffix, determines the format width.  For example, in
    604  * the pattern <code>"* #0 o''clock"</code>, the format width is 10.
    605  *
    606  * <li>The width is counted in 16-bit code units (UChars).
    607  *
    608  * <li>Some parameters which usually do not matter have meaning when padding is
    609  * used, because the pattern width is significant with padding.  In the pattern
    610  * "* ##,##,#,##0.##", the format width is 14.  The initial characters "##,##,"
    611  * do not affect the grouping size or maximum integer digits, but they do affect
    612  * the format width.
    613  *
    614  * <li>Padding may be inserted at one of four locations: before the prefix,
    615  * after the prefix, before the suffix, or after the suffix.  If padding is
    616  * specified in any other location, applyPattern()
    617  * sets a failing UErrorCode.  If there is no prefix,
    618  * before the prefix and after the prefix are equivalent, likewise for the
    619  * suffix.
    620  *
    621  * <li>When specified in a pattern, the 32-bit code point immediately
    622  * following the pad escape is the pad character. This may be any character,
    623  * including a special pattern character. That is, the pad escape
    624  * <em>escapes</em> the following character. If there is no character after
    625  * the pad escape, then the pattern is illegal.
    626  *
    627  * </ul>
    628  *
    629  * <p><strong>Rounding</strong>
    630  *
    631  * <p>DecimalFormat supports rounding to a specific increment.  For
    632  * example, 1230 rounded to the nearest 50 is 1250.  1.234 rounded to the
    633  * nearest 0.65 is 1.3.  The rounding increment may be specified through the API
    634  * or in a pattern.  To specify a rounding increment in a pattern, include the
    635  * increment in the pattern itself.  "#,#50" specifies a rounding increment of
    636  * 50.  "#,##0.05" specifies a rounding increment of 0.05.
    637  *
    638  * <p>In the absense of an explicit rounding increment numbers are
    639  * rounded to their formatted width.
    640  *
    641  * <ul>
    642  * <li>Rounding only affects the string produced by formatting.  It does
    643  * not affect parsing or change any numerical values.
    644  *
    645  * <li>A <em>rounding mode</em> determines how values are rounded; see
    646  * DecimalFormat::ERoundingMode.  The default rounding mode is
    647  * DecimalFormat::kRoundHalfEven.  The rounding mode can only be set
    648  * through the API; it can not be set with a pattern.
    649  *
    650  * <li>Some locales use rounding in their currency formats to reflect the
    651  * smallest currency denomination.
    652  *
    653  * <li>In a pattern, digits '1' through '9' specify rounding, but otherwise
    654  * behave identically to digit '0'.
    655  * </ul>
    656  *
    657  * <p><strong>Synchronization</strong>
    658  *
    659  * <p>DecimalFormat objects are not synchronized.  Multiple
    660  * threads should not access one formatter concurrently.
    661  *
    662  * <p><strong>Subclassing</strong>
    663  *
    664  * <p><em>User subclasses are not supported.</em> While clients may write
    665  * subclasses, such code will not necessarily work and will not be
    666  * guaranteed to work stably from release to release.
    667  */
    668 class U_I18N_API DecimalFormat: public NumberFormat {
    669 public:
    670     /**
    671      * Rounding mode.
    672      * @stable ICU 2.4
    673      */
    674     enum ERoundingMode {
    675         kRoundCeiling,  /**< Round towards positive infinity */
    676         kRoundFloor,    /**< Round towards negative infinity */
    677         kRoundDown,     /**< Round towards zero */
    678         kRoundUp,       /**< Round away from zero */
    679         kRoundHalfEven, /**< Round towards the nearest integer, or
    680                              towards the nearest even integer if equidistant */
    681         kRoundHalfDown, /**< Round towards the nearest integer, or
    682                              towards zero if equidistant */
    683         kRoundHalfUp,   /**< Round towards the nearest integer, or
    684                              away from zero if equidistant */
    685         /**
    686           *  Return U_FORMAT_INEXACT_ERROR if number does not format exactly.
    687           *  @stable ICU 4.8
    688           */
    689         kRoundUnnecessary
    690     };
    691 
    692     /**
    693      * Pad position.
    694      * @stable ICU 2.4
    695      */
    696     enum EPadPosition {
    697         kPadBeforePrefix,
    698         kPadAfterPrefix,
    699         kPadBeforeSuffix,
    700         kPadAfterSuffix
    701     };
    702 
    703     /**
    704      * Create a DecimalFormat using the default pattern and symbols
    705      * for the default locale. This is a convenient way to obtain a
    706      * DecimalFormat when internationalization is not the main concern.
    707      * <P>
    708      * To obtain standard formats for a given locale, use the factory methods
    709      * on NumberFormat such as createInstance. These factories will
    710      * return the most appropriate sub-class of NumberFormat for a given
    711      * locale.
    712      * @param status    Output param set to success/failure code. If the
    713      *                  pattern is invalid this will be set to a failure code.
    714      * @stable ICU 2.0
    715      */
    716     DecimalFormat(UErrorCode& status);
    717 
    718     /**
    719      * Create a DecimalFormat from the given pattern and the symbols
    720      * for the default locale. This is a convenient way to obtain a
    721      * DecimalFormat when internationalization is not the main concern.
    722      * <P>
    723      * To obtain standard formats for a given locale, use the factory methods
    724      * on NumberFormat such as createInstance. These factories will
    725      * return the most appropriate sub-class of NumberFormat for a given
    726      * locale.
    727      * @param pattern   A non-localized pattern string.
    728      * @param status    Output param set to success/failure code. If the
    729      *                  pattern is invalid this will be set to a failure code.
    730      * @stable ICU 2.0
    731      */
    732     DecimalFormat(const UnicodeString& pattern,
    733                   UErrorCode& status);
    734 
    735     /**
    736      * Create a DecimalFormat from the given pattern and symbols.
    737      * Use this constructor when you need to completely customize the
    738      * behavior of the format.
    739      * <P>
    740      * To obtain standard formats for a given
    741      * locale, use the factory methods on NumberFormat such as
    742      * createInstance or createCurrencyInstance. If you need only minor adjustments
    743      * to a standard format, you can modify the format returned by
    744      * a NumberFormat factory method.
    745      *
    746      * @param pattern           a non-localized pattern string
    747      * @param symbolsToAdopt    the set of symbols to be used.  The caller should not
    748      *                          delete this object after making this call.
    749      * @param status            Output param set to success/failure code. If the
    750      *                          pattern is invalid this will be set to a failure code.
    751      * @stable ICU 2.0
    752      */
    753     DecimalFormat(  const UnicodeString& pattern,
    754                     DecimalFormatSymbols* symbolsToAdopt,
    755                     UErrorCode& status);
    756 
    757 #ifndef U_HIDE_INTERNAL_API
    758     /**
    759      * This API is for ICU use only.
    760      * Create a DecimalFormat from the given pattern, symbols, and style.
    761      *
    762      * @param pattern           a non-localized pattern string
    763      * @param symbolsToAdopt    the set of symbols to be used.  The caller should not
    764      *                          delete this object after making this call.
    765      * @param style             style of decimal format
    766      * @param status            Output param set to success/failure code. If the
    767      *                          pattern is invalid this will be set to a failure code.
    768      * @internal
    769      */
    770     DecimalFormat(  const UnicodeString& pattern,
    771                     DecimalFormatSymbols* symbolsToAdopt,
    772                     UNumberFormatStyle style,
    773                     UErrorCode& status);
    774 
    775 #if UCONFIG_HAVE_PARSEALLINPUT
    776     /**
    777      * @internal
    778      */
    779     void setParseAllInput(UNumberFormatAttributeValue value);
    780 #endif
    781 
    782 #endif  /* U_HIDE_INTERNAL_API */
    783 
    784 
    785     /**
    786      * Set an integer attribute on this DecimalFormat.
    787      * May return U_UNSUPPORTED_ERROR if this instance does not support
    788      * the specified attribute.
    789      * @param attr the attribute to set
    790      * @param newvalue new value
    791      * @param status the error type
    792      * @return *this - for chaining (example: format.setAttribute(...).setAttribute(...) )
    793      * @stable ICU 51
    794      */
    795     virtual DecimalFormat& setAttribute( UNumberFormatAttribute attr,
    796                                        int32_t newvalue,
    797                                        UErrorCode &status);
    798 
    799     /**
    800      * Get an integer
    801      * May return U_UNSUPPORTED_ERROR if this instance does not support
    802      * the specified attribute.
    803      * @param attr the attribute to set
    804      * @param status the error type
    805      * @return the attribute value. Undefined if there is an error.
    806      * @stable ICU 51
    807      */
    808     virtual int32_t getAttribute( UNumberFormatAttribute attr,
    809                                   UErrorCode &status) const;
    810 
    811 
    812     /**
    813      * Set whether or not grouping will be used in this format.
    814      * @param newValue    True, grouping will be used in this format.
    815      * @see getGroupingUsed
    816      * @stable ICU 53
    817      */
    818     virtual void setGroupingUsed(UBool newValue);
    819 
    820     /**
    821      * Sets whether or not numbers should be parsed as integers only.
    822      * @param value    set True, this format will parse numbers as integers
    823      *                 only.
    824      * @see isParseIntegerOnly
    825      * @stable ICU 53
    826      */
    827     virtual void setParseIntegerOnly(UBool value);
    828 
    829     /**
    830      * Set a particular UDisplayContext value in the formatter, such as
    831      * UDISPCTX_CAPITALIZATION_FOR_STANDALONE.
    832      * @param value The UDisplayContext value to set.
    833      * @param status Input/output status. If at entry this indicates a failure
    834      *               status, the function will do nothing; otherwise this will be
    835      *               updated with any new status from the function.
    836      * @stable ICU 53
    837      */
    838     virtual void setContext(UDisplayContext value, UErrorCode& status);
    839 
    840     /**
    841      * Create a DecimalFormat from the given pattern and symbols.
    842      * Use this constructor when you need to completely customize the
    843      * behavior of the format.
    844      * <P>
    845      * To obtain standard formats for a given
    846      * locale, use the factory methods on NumberFormat such as
    847      * createInstance or createCurrencyInstance. If you need only minor adjustments
    848      * to a standard format, you can modify the format returned by
    849      * a NumberFormat factory method.
    850      *
    851      * @param pattern           a non-localized pattern string
    852      * @param symbolsToAdopt    the set of symbols to be used.  The caller should not
    853      *                          delete this object after making this call.
    854      * @param parseError        Output param to receive errors occured during parsing
    855      * @param status            Output param set to success/failure code. If the
    856      *                          pattern is invalid this will be set to a failure code.
    857      * @stable ICU 2.0
    858      */
    859     DecimalFormat(  const UnicodeString& pattern,
    860                     DecimalFormatSymbols* symbolsToAdopt,
    861                     UParseError& parseError,
    862                     UErrorCode& status);
    863     /**
    864      * Create a DecimalFormat from the given pattern and symbols.
    865      * Use this constructor when you need to completely customize the
    866      * behavior of the format.
    867      * <P>
    868      * To obtain standard formats for a given
    869      * locale, use the factory methods on NumberFormat such as
    870      * createInstance or createCurrencyInstance. If you need only minor adjustments
    871      * to a standard format, you can modify the format returned by
    872      * a NumberFormat factory method.
    873      *
    874      * @param pattern           a non-localized pattern string
    875      * @param symbols   the set of symbols to be used
    876      * @param status            Output param set to success/failure code. If the
    877      *                          pattern is invalid this will be set to a failure code.
    878      * @stable ICU 2.0
    879      */
    880     DecimalFormat(  const UnicodeString& pattern,
    881                     const DecimalFormatSymbols& symbols,
    882                     UErrorCode& status);
    883 
    884     /**
    885      * Copy constructor.
    886      *
    887      * @param source    the DecimalFormat object to be copied from.
    888      * @stable ICU 2.0
    889      */
    890     DecimalFormat(const DecimalFormat& source);
    891 
    892     /**
    893      * Assignment operator.
    894      *
    895      * @param rhs    the DecimalFormat object to be copied.
    896      * @stable ICU 2.0
    897      */
    898     DecimalFormat& operator=(const DecimalFormat& rhs);
    899 
    900     /**
    901      * Destructor.
    902      * @stable ICU 2.0
    903      */
    904     virtual ~DecimalFormat();
    905 
    906     /**
    907      * Clone this Format object polymorphically. The caller owns the
    908      * result and should delete it when done.
    909      *
    910      * @return    a polymorphic copy of this DecimalFormat.
    911      * @stable ICU 2.0
    912      */
    913     virtual Format* clone(void) const;
    914 
    915     /**
    916      * Return true if the given Format objects are semantically equal.
    917      * Objects of different subclasses are considered unequal.
    918      *
    919      * @param other    the object to be compared with.
    920      * @return         true if the given Format objects are semantically equal.
    921      * @stable ICU 2.0
    922      */
    923     virtual UBool operator==(const Format& other) const;
    924 
    925 
    926     using NumberFormat::format;
    927 
    928     /**
    929      * Format a double or long number using base-10 representation.
    930      *
    931      * @param number    The value to be formatted.
    932      * @param appendTo  Output parameter to receive result.
    933      *                  Result is appended to existing contents.
    934      * @param pos       On input: an alignment field, if desired.
    935      *                  On output: the offsets of the alignment field.
    936      * @return          Reference to 'appendTo' parameter.
    937      * @stable ICU 2.0
    938      */
    939     virtual UnicodeString& format(double number,
    940                                   UnicodeString& appendTo,
    941                                   FieldPosition& pos) const;
    942 
    943 
    944     /**
    945      * Format a double or long number using base-10 representation.
    946      *
    947      * @param number    The value to be formatted.
    948      * @param appendTo  Output parameter to receive result.
    949      *                  Result is appended to existing contents.
    950      * @param pos       On input: an alignment field, if desired.
    951      *                  On output: the offsets of the alignment field.
    952      * @param status
    953      * @return          Reference to 'appendTo' parameter.
    954      * @internal
    955      */
    956     virtual UnicodeString& format(double number,
    957                                   UnicodeString& appendTo,
    958                                   FieldPosition& pos,
    959                                   UErrorCode &status) const;
    960 
    961     /**
    962      * Format a double or long number using base-10 representation.
    963      *
    964      * @param number    The value to be formatted.
    965      * @param appendTo  Output parameter to receive result.
    966      *                  Result is appended to existing contents.
    967      * @param posIter   On return, can be used to iterate over positions
    968      *                  of fields generated by this format call.
    969      *                  Can be NULL.
    970      * @param status    Output param filled with success/failure status.
    971      * @return          Reference to 'appendTo' parameter.
    972      * @stable 4.4
    973      */
    974     virtual UnicodeString& format(double number,
    975                                   UnicodeString& appendTo,
    976                                   FieldPositionIterator* posIter,
    977                                   UErrorCode& status) const;
    978 
    979     /**
    980      * Format a long number using base-10 representation.
    981      *
    982      * @param number    The value to be formatted.
    983      * @param appendTo  Output parameter to receive result.
    984      *                  Result is appended to existing contents.
    985      * @param pos       On input: an alignment field, if desired.
    986      *                  On output: the offsets of the alignment field.
    987      * @return          Reference to 'appendTo' parameter.
    988      * @stable ICU 2.0
    989      */
    990     virtual UnicodeString& format(int32_t number,
    991                                   UnicodeString& appendTo,
    992                                   FieldPosition& pos) const;
    993 
    994     /**
    995      * Format a long number using base-10 representation.
    996      *
    997      * @param number    The value to be formatted.
    998      * @param appendTo  Output parameter to receive result.
    999      *                  Result is appended to existing contents.
   1000      * @param pos       On input: an alignment field, if desired.
   1001      *                  On output: the offsets of the alignment field.
   1002      * @return          Reference to 'appendTo' parameter.
   1003      * @internal
   1004      */
   1005     virtual UnicodeString& format(int32_t number,
   1006                                   UnicodeString& appendTo,
   1007                                   FieldPosition& pos,
   1008                                   UErrorCode &status) const;
   1009 
   1010     /**
   1011      * Format a long number using base-10 representation.
   1012      *
   1013      * @param number    The value to be formatted.
   1014      * @param appendTo  Output parameter to receive result.
   1015      *                  Result is appended to existing contents.
   1016      * @param posIter   On return, can be used to iterate over positions
   1017      *                  of fields generated by this format call.
   1018      *                  Can be NULL.
   1019      * @param status    Output param filled with success/failure status.
   1020      * @return          Reference to 'appendTo' parameter.
   1021      * @stable 4.4
   1022      */
   1023     virtual UnicodeString& format(int32_t number,
   1024                                   UnicodeString& appendTo,
   1025                                   FieldPositionIterator* posIter,
   1026                                   UErrorCode& status) const;
   1027 
   1028     /**
   1029      * Format an int64 number using base-10 representation.
   1030      *
   1031      * @param number    The value to be formatted.
   1032      * @param appendTo  Output parameter to receive result.
   1033      *                  Result is appended to existing contents.
   1034      * @param pos       On input: an alignment field, if desired.
   1035      *                  On output: the offsets of the alignment field.
   1036      * @return          Reference to 'appendTo' parameter.
   1037      * @stable ICU 2.8
   1038      */
   1039     virtual UnicodeString& format(int64_t number,
   1040                                   UnicodeString& appendTo,
   1041                                   FieldPosition& pos) const;
   1042 
   1043     /**
   1044      * Format an int64 number using base-10 representation.
   1045      *
   1046      * @param number    The value to be formatted.
   1047      * @param appendTo  Output parameter to receive result.
   1048      *                  Result is appended to existing contents.
   1049      * @param pos       On input: an alignment field, if desired.
   1050      *                  On output: the offsets of the alignment field.
   1051      * @return          Reference to 'appendTo' parameter.
   1052      * @internal
   1053      */
   1054     virtual UnicodeString& format(int64_t number,
   1055                                   UnicodeString& appendTo,
   1056                                   FieldPosition& pos,
   1057                                   UErrorCode &status) const;
   1058 
   1059     /**
   1060      * Format an int64 number using base-10 representation.
   1061      *
   1062      * @param number    The value to be formatted.
   1063      * @param appendTo  Output parameter to receive result.
   1064      *                  Result is appended to existing contents.
   1065      * @param posIter   On return, can be used to iterate over positions
   1066      *                  of fields generated by this format call.
   1067      *                  Can be NULL.
   1068      * @param status    Output param filled with success/failure status.
   1069      * @return          Reference to 'appendTo' parameter.
   1070      * @stable 4.4
   1071      */
   1072     virtual UnicodeString& format(int64_t number,
   1073                                   UnicodeString& appendTo,
   1074                                   FieldPositionIterator* posIter,
   1075                                   UErrorCode& status) const;
   1076 
   1077     /**
   1078      * Format a decimal number.
   1079      * The syntax of the unformatted number is a "numeric string"
   1080      * as defined in the Decimal Arithmetic Specification, available at
   1081      * http://speleotrove.com/decimal
   1082      *
   1083      * @param number    The unformatted number, as a string.
   1084      * @param appendTo  Output parameter to receive result.
   1085      *                  Result is appended to existing contents.
   1086      * @param posIter   On return, can be used to iterate over positions
   1087      *                  of fields generated by this format call.
   1088      *                  Can be NULL.
   1089      * @param status    Output param filled with success/failure status.
   1090      * @return          Reference to 'appendTo' parameter.
   1091      * @stable 4.4
   1092      */
   1093     virtual UnicodeString& format(const StringPiece &number,
   1094                                   UnicodeString& appendTo,
   1095                                   FieldPositionIterator* posIter,
   1096                                   UErrorCode& status) const;
   1097 
   1098 
   1099     /**
   1100      * Format a decimal number.
   1101      * The number is a DigitList wrapper onto a floating point decimal number.
   1102      * The default implementation in NumberFormat converts the decimal number
   1103      * to a double and formats that.
   1104      *
   1105      * @param number    The number, a DigitList format Decimal Floating Point.
   1106      * @param appendTo  Output parameter to receive result.
   1107      *                  Result is appended to existing contents.
   1108      * @param posIter   On return, can be used to iterate over positions
   1109      *                  of fields generated by this format call.
   1110      * @param status    Output param filled with success/failure status.
   1111      * @return          Reference to 'appendTo' parameter.
   1112      * @internal
   1113      */
   1114     virtual UnicodeString& format(const DigitList &number,
   1115                                   UnicodeString& appendTo,
   1116                                   FieldPositionIterator* posIter,
   1117                                   UErrorCode& status) const;
   1118 
   1119     /**
   1120      * Format a decimal number.
   1121      * @param number    The number
   1122      * @param appendTo  Output parameter to receive result.
   1123      *                  Result is appended to existing contents.
   1124      * @param pos       On input: an alignment field, if desired.
   1125      *                  On output: the offsets of the alignment field.
   1126      * @param status    Output param filled with success/failure status.
   1127      * @return          Reference to 'appendTo' parameter.
   1128      * @internal
   1129      */
   1130     virtual UnicodeString& format(
   1131             const VisibleDigitsWithExponent &number,
   1132             UnicodeString& appendTo,
   1133             FieldPosition& pos,
   1134             UErrorCode& status) const;
   1135 
   1136     /**
   1137      * Format a decimal number.
   1138      * @param number    The number
   1139      * @param appendTo  Output parameter to receive result.
   1140      *                  Result is appended to existing contents.
   1141      * @param posIter   On return, can be used to iterate over positions
   1142      *                  of fields generated by this format call.
   1143      * @param status    Output param filled with success/failure status.
   1144      * @return          Reference to 'appendTo' parameter.
   1145      * @internal
   1146      */
   1147     virtual UnicodeString& format(
   1148             const VisibleDigitsWithExponent &number,
   1149             UnicodeString& appendTo,
   1150             FieldPositionIterator* posIter,
   1151             UErrorCode& status) const;
   1152 
   1153     /**
   1154      * Format a decimal number.
   1155      * The number is a DigitList wrapper onto a floating point decimal number.
   1156      * The default implementation in NumberFormat converts the decimal number
   1157      * to a double and formats that.
   1158      *
   1159      * @param number    The number, a DigitList format Decimal Floating Point.
   1160      * @param appendTo  Output parameter to receive result.
   1161      *                  Result is appended to existing contents.
   1162      * @param pos       On input: an alignment field, if desired.
   1163      *                  On output: the offsets of the alignment field.
   1164      * @param status    Output param filled with success/failure status.
   1165      * @return          Reference to 'appendTo' parameter.
   1166      * @internal
   1167      */
   1168     virtual UnicodeString& format(const DigitList &number,
   1169                                   UnicodeString& appendTo,
   1170                                   FieldPosition& pos,
   1171                                   UErrorCode& status) const;
   1172 
   1173    using NumberFormat::parse;
   1174 
   1175    /**
   1176     * Parse the given string using this object's choices. The method
   1177     * does string comparisons to try to find an optimal match.
   1178     * If no object can be parsed, index is unchanged, and NULL is
   1179     * returned.  The result is returned as the most parsimonious
   1180     * type of Formattable that will accomodate all of the
   1181     * necessary precision.  For example, if the result is exactly 12,
   1182     * it will be returned as a long.  However, if it is 1.5, it will
   1183     * be returned as a double.
   1184     *
   1185     * @param text           The text to be parsed.
   1186     * @param result         Formattable to be set to the parse result.
   1187     *                       If parse fails, return contents are undefined.
   1188     * @param parsePosition  The position to start parsing at on input.
   1189     *                       On output, moved to after the last successfully
   1190     *                       parse character. On parse failure, does not change.
   1191     * @see Formattable
   1192     * @stable ICU 2.0
   1193     */
   1194     virtual void parse(const UnicodeString& text,
   1195                        Formattable& result,
   1196                        ParsePosition& parsePosition) const;
   1197 
   1198     /**
   1199      * Parses text from the given string as a currency amount.  Unlike
   1200      * the parse() method, this method will attempt to parse a generic
   1201      * currency name, searching for a match of this object's locale's
   1202      * currency display names, or for a 3-letter ISO currency code.
   1203      * This method will fail if this format is not a currency format,
   1204      * that is, if it does not contain the currency pattern symbol
   1205      * (U+00A4) in its prefix or suffix.
   1206      *
   1207      * @param text the string to parse
   1208      * @param pos  input-output position; on input, the position within text
   1209      *             to match; must have 0 <= pos.getIndex() < text.length();
   1210      *             on output, the position after the last matched character.
   1211      *             If the parse fails, the position in unchanged upon output.
   1212      * @return     if parse succeeds, a pointer to a newly-created CurrencyAmount
   1213      *             object (owned by the caller) containing information about
   1214      *             the parsed currency; if parse fails, this is NULL.
   1215      * @stable ICU 49
   1216      */
   1217     virtual CurrencyAmount* parseCurrency(const UnicodeString& text,
   1218                                           ParsePosition& pos) const;
   1219 
   1220     /**
   1221      * Returns the decimal format symbols, which is generally not changed
   1222      * by the programmer or user.
   1223      * @return desired DecimalFormatSymbols
   1224      * @see DecimalFormatSymbols
   1225      * @stable ICU 2.0
   1226      */
   1227     virtual const DecimalFormatSymbols* getDecimalFormatSymbols(void) const;
   1228 
   1229     /**
   1230      * Sets the decimal format symbols, which is generally not changed
   1231      * by the programmer or user.
   1232      * @param symbolsToAdopt DecimalFormatSymbols to be adopted.
   1233      * @stable ICU 2.0
   1234      */
   1235     virtual void adoptDecimalFormatSymbols(DecimalFormatSymbols* symbolsToAdopt);
   1236 
   1237     /**
   1238      * Sets the decimal format symbols, which is generally not changed
   1239      * by the programmer or user.
   1240      * @param symbols DecimalFormatSymbols.
   1241      * @stable ICU 2.0
   1242      */
   1243     virtual void setDecimalFormatSymbols(const DecimalFormatSymbols& symbols);
   1244 
   1245 
   1246     /**
   1247      * Returns the currency plural format information,
   1248      * which is generally not changed by the programmer or user.
   1249      * @return desired CurrencyPluralInfo
   1250      * @stable ICU 4.2
   1251      */
   1252     virtual const CurrencyPluralInfo* getCurrencyPluralInfo(void) const;
   1253 
   1254     /**
   1255      * Sets the currency plural format information,
   1256      * which is generally not changed by the programmer or user.
   1257      * @param toAdopt CurrencyPluralInfo to be adopted.
   1258      * @stable ICU 4.2
   1259      */
   1260     virtual void adoptCurrencyPluralInfo(CurrencyPluralInfo* toAdopt);
   1261 
   1262     /**
   1263      * Sets the currency plural format information,
   1264      * which is generally not changed by the programmer or user.
   1265      * @param info Currency Plural Info.
   1266      * @stable ICU 4.2
   1267      */
   1268     virtual void setCurrencyPluralInfo(const CurrencyPluralInfo& info);
   1269 
   1270 
   1271     /**
   1272      * Get the positive prefix.
   1273      *
   1274      * @param result    Output param which will receive the positive prefix.
   1275      * @return          A reference to 'result'.
   1276      * Examples: +123, $123, sFr123
   1277      * @stable ICU 2.0
   1278      */
   1279     UnicodeString& getPositivePrefix(UnicodeString& result) const;
   1280 
   1281     /**
   1282      * Set the positive prefix.
   1283      *
   1284      * @param newValue    the new value of the the positive prefix to be set.
   1285      * Examples: +123, $123, sFr123
   1286      * @stable ICU 2.0
   1287      */
   1288     virtual void setPositivePrefix(const UnicodeString& newValue);
   1289 
   1290     /**
   1291      * Get the negative prefix.
   1292      *
   1293      * @param result    Output param which will receive the negative prefix.
   1294      * @return          A reference to 'result'.
   1295      * Examples: -123, ($123) (with negative suffix), sFr-123
   1296      * @stable ICU 2.0
   1297      */
   1298     UnicodeString& getNegativePrefix(UnicodeString& result) const;
   1299 
   1300     /**
   1301      * Set the negative prefix.
   1302      *
   1303      * @param newValue    the new value of the the negative prefix to be set.
   1304      * Examples: -123, ($123) (with negative suffix), sFr-123
   1305      * @stable ICU 2.0
   1306      */
   1307     virtual void setNegativePrefix(const UnicodeString& newValue);
   1308 
   1309     /**
   1310      * Get the positive suffix.
   1311      *
   1312      * @param result    Output param which will receive the positive suffix.
   1313      * @return          A reference to 'result'.
   1314      * Example: 123%
   1315      * @stable ICU 2.0
   1316      */
   1317     UnicodeString& getPositiveSuffix(UnicodeString& result) const;
   1318 
   1319     /**
   1320      * Set the positive suffix.
   1321      *
   1322      * @param newValue    the new value of the positive suffix to be set.
   1323      * Example: 123%
   1324      * @stable ICU 2.0
   1325      */
   1326     virtual void setPositiveSuffix(const UnicodeString& newValue);
   1327 
   1328     /**
   1329      * Get the negative suffix.
   1330      *
   1331      * @param result    Output param which will receive the negative suffix.
   1332      * @return          A reference to 'result'.
   1333      * Examples: -123%, ($123) (with positive suffixes)
   1334      * @stable ICU 2.0
   1335      */
   1336     UnicodeString& getNegativeSuffix(UnicodeString& result) const;
   1337 
   1338     /**
   1339      * Set the negative suffix.
   1340      *
   1341      * @param newValue    the new value of the negative suffix to be set.
   1342      * Examples: 123%
   1343      * @stable ICU 2.0
   1344      */
   1345     virtual void setNegativeSuffix(const UnicodeString& newValue);
   1346 
   1347     /**
   1348      * Get the multiplier for use in percent, permill, etc.
   1349      * For a percentage, set the suffixes to have "%" and the multiplier to be 100.
   1350      * (For Arabic, use arabic percent symbol).
   1351      * For a permill, set the suffixes to have "\\u2031" and the multiplier to be 1000.
   1352      *
   1353      * @return    the multiplier for use in percent, permill, etc.
   1354      * Examples: with 100, 1.23 -> "123", and "123" -> 1.23
   1355      * @stable ICU 2.0
   1356      */
   1357     int32_t getMultiplier(void) const;
   1358 
   1359     /**
   1360      * Set the multiplier for use in percent, permill, etc.
   1361      * For a percentage, set the suffixes to have "%" and the multiplier to be 100.
   1362      * (For Arabic, use arabic percent symbol).
   1363      * For a permill, set the suffixes to have "\\u2031" and the multiplier to be 1000.
   1364      *
   1365      * @param newValue    the new value of the multiplier for use in percent, permill, etc.
   1366      * Examples: with 100, 1.23 -> "123", and "123" -> 1.23
   1367      * @stable ICU 2.0
   1368      */
   1369     virtual void setMultiplier(int32_t newValue);
   1370 
   1371     /**
   1372      * Get the rounding increment.
   1373      * @return A positive rounding increment, or 0.0 if a custom rounding
   1374      * increment is not in effect.
   1375      * @see #setRoundingIncrement
   1376      * @see #getRoundingMode
   1377      * @see #setRoundingMode
   1378      * @stable ICU 2.0
   1379      */
   1380     virtual double getRoundingIncrement(void) const;
   1381 
   1382     /**
   1383      * Set the rounding increment.  In the absence of a rounding increment,
   1384      *    numbers will be rounded to the number of digits displayed.
   1385      * @param newValue A positive rounding increment, or 0.0 to
   1386      * use the default rounding increment.
   1387      * Negative increments are equivalent to 0.0.
   1388      * @see #getRoundingIncrement
   1389      * @see #getRoundingMode
   1390      * @see #setRoundingMode
   1391      * @stable ICU 2.0
   1392      */
   1393     virtual void setRoundingIncrement(double newValue);
   1394 
   1395     /**
   1396      * Get the rounding mode.
   1397      * @return A rounding mode
   1398      * @see #setRoundingIncrement
   1399      * @see #getRoundingIncrement
   1400      * @see #setRoundingMode
   1401      * @stable ICU 2.0
   1402      */
   1403     virtual ERoundingMode getRoundingMode(void) const;
   1404 
   1405     /**
   1406      * Set the rounding mode.
   1407      * @param roundingMode A rounding mode
   1408      * @see #setRoundingIncrement
   1409      * @see #getRoundingIncrement
   1410      * @see #getRoundingMode
   1411      * @stable ICU 2.0
   1412      */
   1413     virtual void setRoundingMode(ERoundingMode roundingMode);
   1414 
   1415     /**
   1416      * Get the width to which the output of format() is padded.
   1417      * The width is counted in 16-bit code units.
   1418      * @return the format width, or zero if no padding is in effect
   1419      * @see #setFormatWidth
   1420      * @see #getPadCharacterString
   1421      * @see #setPadCharacter
   1422      * @see #getPadPosition
   1423      * @see #setPadPosition
   1424      * @stable ICU 2.0
   1425      */
   1426     virtual int32_t getFormatWidth(void) const;
   1427 
   1428     /**
   1429      * Set the width to which the output of format() is padded.
   1430      * The width is counted in 16-bit code units.
   1431      * This method also controls whether padding is enabled.
   1432      * @param width the width to which to pad the result of
   1433      * format(), or zero to disable padding.  A negative
   1434      * width is equivalent to 0.
   1435      * @see #getFormatWidth
   1436      * @see #getPadCharacterString
   1437      * @see #setPadCharacter
   1438      * @see #getPadPosition
   1439      * @see #setPadPosition
   1440      * @stable ICU 2.0
   1441      */
   1442     virtual void setFormatWidth(int32_t width);
   1443 
   1444     /**
   1445      * Get the pad character used to pad to the format width.  The
   1446      * default is ' '.
   1447      * @return a string containing the pad character. This will always
   1448      * have a length of one 32-bit code point.
   1449      * @see #setFormatWidth
   1450      * @see #getFormatWidth
   1451      * @see #setPadCharacter
   1452      * @see #getPadPosition
   1453      * @see #setPadPosition
   1454      * @stable ICU 2.0
   1455      */
   1456     virtual UnicodeString getPadCharacterString() const;
   1457 
   1458     /**
   1459      * Set the character used to pad to the format width.  If padding
   1460      * is not enabled, then this will take effect if padding is later
   1461      * enabled.
   1462      * @param padChar a string containing the pad charcter. If the string
   1463      * has length 0, then the pad characer is set to ' '.  Otherwise
   1464      * padChar.char32At(0) will be used as the pad character.
   1465      * @see #setFormatWidth
   1466      * @see #getFormatWidth
   1467      * @see #getPadCharacterString
   1468      * @see #getPadPosition
   1469      * @see #setPadPosition
   1470      * @stable ICU 2.0
   1471      */
   1472     virtual void setPadCharacter(const UnicodeString &padChar);
   1473 
   1474     /**
   1475      * Get the position at which padding will take place.  This is the location
   1476      * at which padding will be inserted if the result of format()
   1477      * is shorter than the format width.
   1478      * @return the pad position, one of kPadBeforePrefix,
   1479      * kPadAfterPrefix, kPadBeforeSuffix, or
   1480      * kPadAfterSuffix.
   1481      * @see #setFormatWidth
   1482      * @see #getFormatWidth
   1483      * @see #setPadCharacter
   1484      * @see #getPadCharacterString
   1485      * @see #setPadPosition
   1486      * @see #EPadPosition
   1487      * @stable ICU 2.0
   1488      */
   1489     virtual EPadPosition getPadPosition(void) const;
   1490 
   1491     /**
   1492      * Set the position at which padding will take place.  This is the location
   1493      * at which padding will be inserted if the result of format()
   1494      * is shorter than the format width.  This has no effect unless padding is
   1495      * enabled.
   1496      * @param padPos the pad position, one of kPadBeforePrefix,
   1497      * kPadAfterPrefix, kPadBeforeSuffix, or
   1498      * kPadAfterSuffix.
   1499      * @see #setFormatWidth
   1500      * @see #getFormatWidth
   1501      * @see #setPadCharacter
   1502      * @see #getPadCharacterString
   1503      * @see #getPadPosition
   1504      * @see #EPadPosition
   1505      * @stable ICU 2.0
   1506      */
   1507     virtual void setPadPosition(EPadPosition padPos);
   1508 
   1509     /**
   1510      * Return whether or not scientific notation is used.
   1511      * @return TRUE if this object formats and parses scientific notation
   1512      * @see #setScientificNotation
   1513      * @see #getMinimumExponentDigits
   1514      * @see #setMinimumExponentDigits
   1515      * @see #isExponentSignAlwaysShown
   1516      * @see #setExponentSignAlwaysShown
   1517      * @stable ICU 2.0
   1518      */
   1519     virtual UBool isScientificNotation(void) const;
   1520 
   1521     /**
   1522      * Set whether or not scientific notation is used. When scientific notation
   1523      * is used, the effective maximum number of integer digits is <= 8.  If the
   1524      * maximum number of integer digits is set to more than 8, the effective
   1525      * maximum will be 1.  This allows this call to generate a 'default' scientific
   1526      * number format without additional changes.
   1527      * @param useScientific TRUE if this object formats and parses scientific
   1528      * notation
   1529      * @see #isScientificNotation
   1530      * @see #getMinimumExponentDigits
   1531      * @see #setMinimumExponentDigits
   1532      * @see #isExponentSignAlwaysShown
   1533      * @see #setExponentSignAlwaysShown
   1534      * @stable ICU 2.0
   1535      */
   1536     virtual void setScientificNotation(UBool useScientific);
   1537 
   1538     /**
   1539      * Return the minimum exponent digits that will be shown.
   1540      * @return the minimum exponent digits that will be shown
   1541      * @see #setScientificNotation
   1542      * @see #isScientificNotation
   1543      * @see #setMinimumExponentDigits
   1544      * @see #isExponentSignAlwaysShown
   1545      * @see #setExponentSignAlwaysShown
   1546      * @stable ICU 2.0
   1547      */
   1548     virtual int8_t getMinimumExponentDigits(void) const;
   1549 
   1550     /**
   1551      * Set the minimum exponent digits that will be shown.  This has no
   1552      * effect unless scientific notation is in use.
   1553      * @param minExpDig a value >= 1 indicating the fewest exponent digits
   1554      * that will be shown.  Values less than 1 will be treated as 1.
   1555      * @see #setScientificNotation
   1556      * @see #isScientificNotation
   1557      * @see #getMinimumExponentDigits
   1558      * @see #isExponentSignAlwaysShown
   1559      * @see #setExponentSignAlwaysShown
   1560      * @stable ICU 2.0
   1561      */
   1562     virtual void setMinimumExponentDigits(int8_t minExpDig);
   1563 
   1564     /**
   1565      * Return whether the exponent sign is always shown.
   1566      * @return TRUE if the exponent is always prefixed with either the
   1567      * localized minus sign or the localized plus sign, false if only negative
   1568      * exponents are prefixed with the localized minus sign.
   1569      * @see #setScientificNotation
   1570      * @see #isScientificNotation
   1571      * @see #setMinimumExponentDigits
   1572      * @see #getMinimumExponentDigits
   1573      * @see #setExponentSignAlwaysShown
   1574      * @stable ICU 2.0
   1575      */
   1576     virtual UBool isExponentSignAlwaysShown(void) const;
   1577 
   1578     /**
   1579      * Set whether the exponent sign is always shown.  This has no effect
   1580      * unless scientific notation is in use.
   1581      * @param expSignAlways TRUE if the exponent is always prefixed with either
   1582      * the localized minus sign or the localized plus sign, false if only
   1583      * negative exponents are prefixed with the localized minus sign.
   1584      * @see #setScientificNotation
   1585      * @see #isScientificNotation
   1586      * @see #setMinimumExponentDigits
   1587      * @see #getMinimumExponentDigits
   1588      * @see #isExponentSignAlwaysShown
   1589      * @stable ICU 2.0
   1590      */
   1591     virtual void setExponentSignAlwaysShown(UBool expSignAlways);
   1592 
   1593     /**
   1594      * Return the grouping size. Grouping size is the number of digits between
   1595      * grouping separators in the integer portion of a number.  For example,
   1596      * in the number "123,456.78", the grouping size is 3.
   1597      *
   1598      * @return    the grouping size.
   1599      * @see setGroupingSize
   1600      * @see NumberFormat::isGroupingUsed
   1601      * @see DecimalFormatSymbols::getGroupingSeparator
   1602      * @stable ICU 2.0
   1603      */
   1604     int32_t getGroupingSize(void) const;
   1605 
   1606     /**
   1607      * Set the grouping size. Grouping size is the number of digits between
   1608      * grouping separators in the integer portion of a number.  For example,
   1609      * in the number "123,456.78", the grouping size is 3.
   1610      *
   1611      * @param newValue    the new value of the grouping size.
   1612      * @see getGroupingSize
   1613      * @see NumberFormat::setGroupingUsed
   1614      * @see DecimalFormatSymbols::setGroupingSeparator
   1615      * @stable ICU 2.0
   1616      */
   1617     virtual void setGroupingSize(int32_t newValue);
   1618 
   1619     /**
   1620      * Return the secondary grouping size. In some locales one
   1621      * grouping interval is used for the least significant integer
   1622      * digits (the primary grouping size), and another is used for all
   1623      * others (the secondary grouping size).  A formatter supporting a
   1624      * secondary grouping size will return a positive integer unequal
   1625      * to the primary grouping size returned by
   1626      * getGroupingSize().  For example, if the primary
   1627      * grouping size is 4, and the secondary grouping size is 2, then
   1628      * the number 123456789 formats as "1,23,45,6789", and the pattern
   1629      * appears as "#,##,###0".
   1630      * @return the secondary grouping size, or a value less than
   1631      * one if there is none
   1632      * @see setSecondaryGroupingSize
   1633      * @see NumberFormat::isGroupingUsed
   1634      * @see DecimalFormatSymbols::getGroupingSeparator
   1635      * @stable ICU 2.4
   1636      */
   1637     int32_t getSecondaryGroupingSize(void) const;
   1638 
   1639     /**
   1640      * Set the secondary grouping size. If set to a value less than 1,
   1641      * then secondary grouping is turned off, and the primary grouping
   1642      * size is used for all intervals, not just the least significant.
   1643      *
   1644      * @param newValue    the new value of the secondary grouping size.
   1645      * @see getSecondaryGroupingSize
   1646      * @see NumberFormat#setGroupingUsed
   1647      * @see DecimalFormatSymbols::setGroupingSeparator
   1648      * @stable ICU 2.4
   1649      */
   1650     virtual void setSecondaryGroupingSize(int32_t newValue);
   1651 
   1652 #ifndef U_HIDE_INTERNAL_API
   1653 
   1654     /**
   1655      * Returns the minimum number of grouping digits.
   1656      * Grouping separators are output if there are at least this many
   1657      * digits to the left of the first (rightmost) grouping separator,
   1658      * that is, there are at least (minimum grouping + grouping size) integer digits.
   1659      * (Subject to isGroupingUsed().)
   1660      *
   1661      * For example, if this value is 2, and the grouping size is 3, then
   1662      * 9999 -> "9999" and 10000 -> "10,000"
   1663      *
   1664      * This is a technology preview. This API may change behavior or may be removed.
   1665      *
   1666      * The default value for this attribute is 0.
   1667      * A value of 1, 0, or lower, means that the use of grouping separators
   1668      * only depends on the grouping size (and on isGroupingUsed()).
   1669      * Currently, the corresponding CLDR data is not used; this is likely to change.
   1670      *
   1671      * @see setMinimumGroupingDigits
   1672      * @see getGroupingSize
   1673      * @internal technology preview
   1674      */
   1675     int32_t getMinimumGroupingDigits() const;
   1676 
   1677     /**
   1678      * Sets the minimum grouping digits. Setting to a value less than or
   1679      * equal to 1 turns off minimum grouping digits.
   1680      *
   1681      * @param newValue the new value of minimum grouping digits.
   1682      * @see getMinimumGroupingDigits
   1683      * @internal technology preview
   1684      */
   1685     virtual void setMinimumGroupingDigits(int32_t newValue);
   1686 
   1687 #endif  /* U_HIDE_INTERNAL_API */
   1688 
   1689     /**
   1690      * Allows you to get the behavior of the decimal separator with integers.
   1691      * (The decimal separator will always appear with decimals.)
   1692      *
   1693      * @return    TRUE if the decimal separator always appear with decimals.
   1694      * Example: Decimal ON: 12345 -> 12345.; OFF: 12345 -> 12345
   1695      * @stable ICU 2.0
   1696      */
   1697     UBool isDecimalSeparatorAlwaysShown(void) const;
   1698 
   1699     /**
   1700      * Allows you to set the behavior of the decimal separator with integers.
   1701      * (The decimal separator will always appear with decimals.)
   1702      *
   1703      * @param newValue    set TRUE if the decimal separator will always appear with decimals.
   1704      * Example: Decimal ON: 12345 -> 12345.; OFF: 12345 -> 12345
   1705      * @stable ICU 2.0
   1706      */
   1707     virtual void setDecimalSeparatorAlwaysShown(UBool newValue);
   1708 
   1709     /**
   1710      * Allows you to get the parse behavior of the pattern decimal mark.
   1711      *
   1712      * @return    TRUE if input must contain a match to decimal mark in pattern
   1713      * @stable ICU 54
   1714      */
   1715     UBool isDecimalPatternMatchRequired(void) const;
   1716 
   1717     /**
   1718      * Allows you to set the behavior of the pattern decimal mark.
   1719      *
   1720      * if TRUE, the input must have a decimal mark if one was specified in the pattern. When
   1721      * FALSE the decimal mark may be omitted from the input.
   1722      *
   1723      * @param newValue    set TRUE if input must contain a match to decimal mark in pattern
   1724      * @stable ICU 54
   1725      */
   1726     virtual void setDecimalPatternMatchRequired(UBool newValue);
   1727 
   1728 
   1729     /**
   1730      * Synthesizes a pattern string that represents the current state
   1731      * of this Format object.
   1732      *
   1733      * @param result    Output param which will receive the pattern.
   1734      *                  Previous contents are deleted.
   1735      * @return          A reference to 'result'.
   1736      * @see applyPattern
   1737      * @stable ICU 2.0
   1738      */
   1739     virtual UnicodeString& toPattern(UnicodeString& result) const;
   1740 
   1741     /**
   1742      * Synthesizes a localized pattern string that represents the current
   1743      * state of this Format object.
   1744      *
   1745      * @param result    Output param which will receive the localized pattern.
   1746      *                  Previous contents are deleted.
   1747      * @return          A reference to 'result'.
   1748      * @see applyPattern
   1749      * @stable ICU 2.0
   1750      */
   1751     virtual UnicodeString& toLocalizedPattern(UnicodeString& result) const;
   1752 
   1753     /**
   1754      * Apply the given pattern to this Format object.  A pattern is a
   1755      * short-hand specification for the various formatting properties.
   1756      * These properties can also be changed individually through the
   1757      * various setter methods.
   1758      * <P>
   1759      * There is no limit to integer digits are set
   1760      * by this routine, since that is the typical end-user desire;
   1761      * use setMaximumInteger if you want to set a real value.
   1762      * For negative numbers, use a second pattern, separated by a semicolon
   1763      * <pre>
   1764      * .      Example "#,#00.0#" -> 1,234.56
   1765      * </pre>
   1766      * This means a minimum of 2 integer digits, 1 fraction digit, and
   1767      * a maximum of 2 fraction digits.
   1768      * <pre>
   1769      * .      Example: "#,#00.0#;(#,#00.0#)" for negatives in parantheses.
   1770      * </pre>
   1771      * In negative patterns, the minimum and maximum counts are ignored;
   1772      * these are presumed to be set in the positive pattern.
   1773      *
   1774      * @param pattern    The pattern to be applied.
   1775      * @param parseError Struct to recieve information on position
   1776      *                   of error if an error is encountered
   1777      * @param status     Output param set to success/failure code on
   1778      *                   exit. If the pattern is invalid, this will be
   1779      *                   set to a failure result.
   1780      * @stable ICU 2.0
   1781      */
   1782     virtual void applyPattern(const UnicodeString& pattern,
   1783                              UParseError& parseError,
   1784                              UErrorCode& status);
   1785     /**
   1786      * Sets the pattern.
   1787      * @param pattern   The pattern to be applied.
   1788      * @param status    Output param set to success/failure code on
   1789      *                  exit. If the pattern is invalid, this will be
   1790      *                  set to a failure result.
   1791      * @stable ICU 2.0
   1792      */
   1793     virtual void applyPattern(const UnicodeString& pattern,
   1794                              UErrorCode& status);
   1795 
   1796     /**
   1797      * Apply the given pattern to this Format object.  The pattern
   1798      * is assumed to be in a localized notation. A pattern is a
   1799      * short-hand specification for the various formatting properties.
   1800      * These properties can also be changed individually through the
   1801      * various setter methods.
   1802      * <P>
   1803      * There is no limit to integer digits are set
   1804      * by this routine, since that is the typical end-user desire;
   1805      * use setMaximumInteger if you want to set a real value.
   1806      * For negative numbers, use a second pattern, separated by a semicolon
   1807      * <pre>
   1808      * .      Example "#,#00.0#" -> 1,234.56
   1809      * </pre>
   1810      * This means a minimum of 2 integer digits, 1 fraction digit, and
   1811      * a maximum of 2 fraction digits.
   1812      *
   1813      * Example: "#,#00.0#;(#,#00.0#)" for negatives in parantheses.
   1814      *
   1815      * In negative patterns, the minimum and maximum counts are ignored;
   1816      * these are presumed to be set in the positive pattern.
   1817      *
   1818      * @param pattern   The localized pattern to be applied.
   1819      * @param parseError Struct to recieve information on position
   1820      *                   of error if an error is encountered
   1821      * @param status    Output param set to success/failure code on
   1822      *                  exit. If the pattern is invalid, this will be
   1823      *                  set to a failure result.
   1824      * @stable ICU 2.0
   1825      */
   1826     virtual void applyLocalizedPattern(const UnicodeString& pattern,
   1827                                        UParseError& parseError,
   1828                                        UErrorCode& status);
   1829 
   1830     /**
   1831      * Apply the given pattern to this Format object.
   1832      *
   1833      * @param pattern   The localized pattern to be applied.
   1834      * @param status    Output param set to success/failure code on
   1835      *                  exit. If the pattern is invalid, this will be
   1836      *                  set to a failure result.
   1837      * @stable ICU 2.0
   1838      */
   1839     virtual void applyLocalizedPattern(const UnicodeString& pattern,
   1840                                        UErrorCode& status);
   1841 
   1842 
   1843     /**
   1844      * Sets the maximum number of digits allowed in the integer portion of a
   1845      * number. This override limits the integer digit count to 309.
   1846      *
   1847      * @param newValue    the new value of the maximum number of digits
   1848      *                      allowed in the integer portion of a number.
   1849      * @see NumberFormat#setMaximumIntegerDigits
   1850      * @stable ICU 2.0
   1851      */
   1852     virtual void setMaximumIntegerDigits(int32_t newValue);
   1853 
   1854     /**
   1855      * Sets the minimum number of digits allowed in the integer portion of a
   1856      * number. This override limits the integer digit count to 309.
   1857      *
   1858      * @param newValue    the new value of the minimum number of digits
   1859      *                      allowed in the integer portion of a number.
   1860      * @see NumberFormat#setMinimumIntegerDigits
   1861      * @stable ICU 2.0
   1862      */
   1863     virtual void setMinimumIntegerDigits(int32_t newValue);
   1864 
   1865     /**
   1866      * Sets the maximum number of digits allowed in the fraction portion of a
   1867      * number. This override limits the fraction digit count to 340.
   1868      *
   1869      * @param newValue    the new value of the maximum number of digits
   1870      *                    allowed in the fraction portion of a number.
   1871      * @see NumberFormat#setMaximumFractionDigits
   1872      * @stable ICU 2.0
   1873      */
   1874     virtual void setMaximumFractionDigits(int32_t newValue);
   1875 
   1876     /**
   1877      * Sets the minimum number of digits allowed in the fraction portion of a
   1878      * number. This override limits the fraction digit count to 340.
   1879      *
   1880      * @param newValue    the new value of the minimum number of digits
   1881      *                    allowed in the fraction portion of a number.
   1882      * @see NumberFormat#setMinimumFractionDigits
   1883      * @stable ICU 2.0
   1884      */
   1885     virtual void setMinimumFractionDigits(int32_t newValue);
   1886 
   1887     /**
   1888      * Returns the minimum number of significant digits that will be
   1889      * displayed. This value has no effect unless areSignificantDigitsUsed()
   1890      * returns true.
   1891      * @return the fewest significant digits that will be shown
   1892      * @stable ICU 3.0
   1893      */
   1894     int32_t getMinimumSignificantDigits() const;
   1895 
   1896     /**
   1897      * Returns the maximum number of significant digits that will be
   1898      * displayed. This value has no effect unless areSignificantDigitsUsed()
   1899      * returns true.
   1900      * @return the most significant digits that will be shown
   1901      * @stable ICU 3.0
   1902      */
   1903     int32_t getMaximumSignificantDigits() const;
   1904 
   1905     /**
   1906      * Sets the minimum number of significant digits that will be
   1907      * displayed.  If <code>min</code> is less than one then it is set
   1908      * to one.  If the maximum significant digits count is less than
   1909      * <code>min</code>, then it is set to <code>min</code>.
   1910      * This function also enables the use of significant digits
   1911      * by this formatter - areSignificantDigitsUsed() will return TRUE.
   1912      * @see #areSignificantDigitsUsed
   1913      * @param min the fewest significant digits to be shown
   1914      * @stable ICU 3.0
   1915      */
   1916     void setMinimumSignificantDigits(int32_t min);
   1917 
   1918     /**
   1919      * Sets the maximum number of significant digits that will be
   1920      * displayed.  If <code>max</code> is less than one then it is set
   1921      * to one.  If the minimum significant digits count is greater
   1922      * than <code>max</code>, then it is set to <code>max</code>.
   1923      * This function also enables the use of significant digits
   1924      * by this formatter - areSignificantDigitsUsed() will return TRUE.
   1925      * @see #areSignificantDigitsUsed
   1926      * @param max the most significant digits to be shown
   1927      * @stable ICU 3.0
   1928      */
   1929     void setMaximumSignificantDigits(int32_t max);
   1930 
   1931     /**
   1932      * Returns true if significant digits are in use, or false if
   1933      * integer and fraction digit counts are in use.
   1934      * @return true if significant digits are in use
   1935      * @stable ICU 3.0
   1936      */
   1937     UBool areSignificantDigitsUsed() const;
   1938 
   1939     /**
   1940      * Sets whether significant digits are in use, or integer and
   1941      * fraction digit counts are in use.
   1942      * @param useSignificantDigits true to use significant digits, or
   1943      * false to use integer and fraction digit counts
   1944      * @stable ICU 3.0
   1945      */
   1946     void setSignificantDigitsUsed(UBool useSignificantDigits);
   1947 
   1948  public:
   1949     /**
   1950      * Sets the currency used to display currency
   1951      * amounts.  This takes effect immediately, if this format is a
   1952      * currency format.  If this format is not a currency format, then
   1953      * the currency is used if and when this object becomes a
   1954      * currency format through the application of a new pattern.
   1955      * @param theCurrency a 3-letter ISO code indicating new currency
   1956      * to use.  It need not be null-terminated.  May be the empty
   1957      * string or NULL to indicate no currency.
   1958      * @param ec input-output error code
   1959      * @stable ICU 3.0
   1960      */
   1961     virtual void setCurrency(const UChar* theCurrency, UErrorCode& ec);
   1962 
   1963     /**
   1964      * Sets the currency used to display currency amounts.  See
   1965      * setCurrency(const UChar*, UErrorCode&).
   1966      * @deprecated ICU 3.0. Use setCurrency(const UChar*, UErrorCode&).
   1967      */
   1968     virtual void setCurrency(const UChar* theCurrency);
   1969 
   1970     /**
   1971      * Sets the <tt>Currency Context</tt> object used to display currency.
   1972      * This takes effect immediately, if this format is a
   1973      * currency format.
   1974      * @param currencyContext new currency context object to use.
   1975      * @stable ICU 54
   1976      */
   1977     void setCurrencyUsage(UCurrencyUsage newUsage, UErrorCode* ec);
   1978 
   1979     /**
   1980      * Returns the <tt>Currency Context</tt> object used to display currency
   1981      * @stable ICU 54
   1982      */
   1983     UCurrencyUsage getCurrencyUsage() const;
   1984 
   1985 
   1986 #ifndef U_HIDE_DEPRECATED_API
   1987     /**
   1988      * The resource tags we use to retrieve decimal format data from
   1989      * locale resource bundles.
   1990      * @deprecated ICU 3.4. This string has no public purpose. Please don't use it.
   1991      */
   1992     static const char fgNumberPatterns[];
   1993 #endif  /* U_HIDE_DEPRECATED_API */
   1994 
   1995 #ifndef U_HIDE_INTERNAL_API
   1996     /**
   1997      *  Get a FixedDecimal corresponding to a double as it would be
   1998      *  formatted by this DecimalFormat.
   1999      *  Internal, not intended for public use.
   2000      *  @internal
   2001      */
   2002      FixedDecimal getFixedDecimal(double number, UErrorCode &status) const;
   2003 
   2004     /**
   2005      *  Get a FixedDecimal corresponding to a formattable as it would be
   2006      *  formatted by this DecimalFormat.
   2007      *  Internal, not intended for public use.
   2008      *  @internal
   2009      */
   2010      FixedDecimal getFixedDecimal(const Formattable &number, UErrorCode &status) const;
   2011 
   2012     /**
   2013      *  Get a FixedDecimal corresponding to a DigitList as it would be
   2014      *  formatted by this DecimalFormat. Note: the DigitList may be modified.
   2015      *  Internal, not intended for public use.
   2016      *  @internal
   2017      */
   2018      FixedDecimal getFixedDecimal(DigitList &number, UErrorCode &status) const;
   2019 
   2020     /**
   2021      *  Get a VisibleDigitsWithExponent corresponding to a double
   2022      *  as it would be formatted by this DecimalFormat.
   2023      *  Internal, not intended for public use.
   2024      *  @internal
   2025      */
   2026      VisibleDigitsWithExponent &initVisibleDigitsWithExponent(
   2027              double number,
   2028              VisibleDigitsWithExponent &digits,
   2029              UErrorCode &status) const;
   2030 
   2031     /**
   2032      *  Get a VisibleDigitsWithExponent corresponding to a formattable
   2033      *  as it would be formatted by this DecimalFormat.
   2034      *  Internal, not intended for public use.
   2035      *  @internal
   2036      */
   2037      VisibleDigitsWithExponent &initVisibleDigitsWithExponent(
   2038              const Formattable &number,
   2039              VisibleDigitsWithExponent &digits,
   2040              UErrorCode &status) const;
   2041 
   2042     /**
   2043      *  Get a VisibleDigitsWithExponent corresponding to a DigitList
   2044      *  as it would be formatted by this DecimalFormat.
   2045      *  Note: the DigitList may be modified.
   2046      *  Internal, not intended for public use.
   2047      *  @internal
   2048      */
   2049      VisibleDigitsWithExponent &initVisibleDigitsWithExponent(
   2050              DigitList &number,
   2051              VisibleDigitsWithExponent &digits,
   2052              UErrorCode &status) const;
   2053 
   2054 #endif  /* U_HIDE_INTERNAL_API */
   2055 
   2056 public:
   2057 
   2058     /**
   2059      * Return the class ID for this class.  This is useful only for
   2060      * comparing to a return value from getDynamicClassID().  For example:
   2061      * <pre>
   2062      * .      Base* polymorphic_pointer = createPolymorphicObject();
   2063      * .      if (polymorphic_pointer->getDynamicClassID() ==
   2064      * .          Derived::getStaticClassID()) ...
   2065      * </pre>
   2066      * @return          The class ID for all objects of this class.
   2067      * @stable ICU 2.0
   2068      */
   2069     static UClassID U_EXPORT2 getStaticClassID(void);
   2070 
   2071     /**
   2072      * Returns a unique class ID POLYMORPHICALLY.  Pure virtual override.
   2073      * This method is to implement a simple version of RTTI, since not all
   2074      * C++ compilers support genuine RTTI.  Polymorphic operator==() and
   2075      * clone() methods call this method.
   2076      *
   2077      * @return          The class ID for this object. All objects of a
   2078      *                  given class have the same class ID.  Objects of
   2079      *                  other classes have different class IDs.
   2080      * @stable ICU 2.0
   2081      */
   2082     virtual UClassID getDynamicClassID(void) const;
   2083 
   2084 private:
   2085 
   2086     DecimalFormat(); // default constructor not implemented
   2087 
   2088     /**
   2089      *   Initialize all fields of a new DecimalFormatter to a safe default value.
   2090      *      Common code for use by constructors.
   2091      */
   2092     void init();
   2093 
   2094     /**
   2095      * Do real work of constructing a new DecimalFormat.
   2096      */
   2097     void construct(UErrorCode&              status,
   2098                    UParseError&             parseErr,
   2099                    const UnicodeString*     pattern = 0,
   2100                    DecimalFormatSymbols*    symbolsToAdopt = 0
   2101                    );
   2102 
   2103     void parse(const UnicodeString& text,
   2104                Formattable& result,
   2105                ParsePosition& pos,
   2106                UChar* currency) const;
   2107 
   2108     enum {
   2109         fgStatusInfinite,
   2110         fgStatusLength      // Leave last in list.
   2111     } StatusFlags;
   2112 
   2113     UBool subparse(const UnicodeString& text,
   2114                    const UnicodeString* negPrefix,
   2115                    const UnicodeString* negSuffix,
   2116                    const UnicodeString* posPrefix,
   2117                    const UnicodeString* posSuffix,
   2118                    UBool complexCurrencyParsing,
   2119                    int8_t type,
   2120                    ParsePosition& parsePosition,
   2121                    DigitList& digits, UBool* status,
   2122                    UChar* currency) const;
   2123 
   2124     // Mixed style parsing for currency.
   2125     // It parses against the current currency pattern
   2126     // using complex affix comparison
   2127     // parses against the currency plural patterns using complex affix comparison,
   2128     // and parses against the current pattern using simple affix comparison.
   2129     UBool parseForCurrency(const UnicodeString& text,
   2130                            ParsePosition& parsePosition,
   2131                            DigitList& digits,
   2132                            UBool* status,
   2133                            UChar* currency) const;
   2134 
   2135     int32_t skipPadding(const UnicodeString& text, int32_t position) const;
   2136 
   2137     int32_t compareAffix(const UnicodeString& input,
   2138                          int32_t pos,
   2139                          UBool isNegative,
   2140                          UBool isPrefix,
   2141                          const UnicodeString* affixPat,
   2142                          UBool complexCurrencyParsing,
   2143                          int8_t type,
   2144                          UChar* currency) const;
   2145 
   2146     static UnicodeString& trimMarksFromAffix(const UnicodeString& affix, UnicodeString& trimmedAffix);
   2147 
   2148     UBool equalWithSignCompatibility(UChar32 lhs, UChar32 rhs) const;
   2149 
   2150     int32_t compareSimpleAffix(const UnicodeString& affix,
   2151                                       const UnicodeString& input,
   2152                                       int32_t pos,
   2153                                       UBool lenient) const;
   2154 
   2155     static int32_t skipPatternWhiteSpace(const UnicodeString& text, int32_t pos);
   2156 
   2157     static int32_t skipUWhiteSpace(const UnicodeString& text, int32_t pos);
   2158 
   2159     static int32_t skipUWhiteSpaceAndMarks(const UnicodeString& text, int32_t pos);
   2160 
   2161     static int32_t skipBidiMarks(const UnicodeString& text, int32_t pos);
   2162 
   2163     int32_t compareComplexAffix(const UnicodeString& affixPat,
   2164                                 const UnicodeString& input,
   2165                                 int32_t pos,
   2166                                 int8_t type,
   2167                                 UChar* currency) const;
   2168 
   2169     static int32_t match(const UnicodeString& text, int32_t pos, UChar32 ch);
   2170 
   2171     static int32_t match(const UnicodeString& text, int32_t pos, const UnicodeString& str);
   2172 
   2173     static UBool matchSymbol(const UnicodeString &text, int32_t position, int32_t length, const UnicodeString &symbol,
   2174                              UnicodeSet *sset, UChar32 schar);
   2175 
   2176     static UBool matchDecimal(UChar32 symbolChar,
   2177                             UBool sawDecimal,  UChar32 sawDecimalChar,
   2178                              const UnicodeSet *sset, UChar32 schar);
   2179 
   2180     static UBool matchGrouping(UChar32 groupingChar,
   2181                             UBool sawGrouping, UChar32 sawGroupingChar,
   2182                              const UnicodeSet *sset,
   2183                              UChar32 decimalChar, const UnicodeSet *decimalSet,
   2184                              UChar32 schar);
   2185 
   2186     // set up currency affix patterns for mix parsing.
   2187     // The patterns saved here are the affix patterns of default currency
   2188     // pattern and the unique affix patterns of the plural currency patterns.
   2189     // Those patterns are used by parseForCurrency().
   2190     void setupCurrencyAffixPatterns(UErrorCode& status);
   2191 
   2192     // get the currency rounding with respect to currency usage
   2193     double getCurrencyRounding(const UChar* currency,
   2194                                UErrorCode* ec) const;
   2195 
   2196     // get the currency fraction with respect to currency usage
   2197     int getCurrencyFractionDigits(const UChar* currency,
   2198                                   UErrorCode* ec) const;
   2199 
   2200     // hashtable operations
   2201     Hashtable* initHashForAffixPattern(UErrorCode& status);
   2202 
   2203     void deleteHashForAffixPattern();
   2204 
   2205     void copyHashForAffixPattern(const Hashtable* source,
   2206                                  Hashtable* target, UErrorCode& status);
   2207 
   2208     DecimalFormatImpl *fImpl;
   2209 
   2210     /**
   2211      * Constants.
   2212      */
   2213 
   2214 
   2215     EnumSet<UNumberFormatAttribute,
   2216             UNUM_MAX_NONBOOLEAN_ATTRIBUTE+1,
   2217             UNUM_LIMIT_BOOLEAN_ATTRIBUTE>
   2218                             fBoolFlags;
   2219 
   2220 
   2221     // style is only valid when decimal formatter is constructed by
   2222     // DecimalFormat(pattern, decimalFormatSymbol, style)
   2223     int fStyle;
   2224 
   2225 
   2226     // Affix pattern set for currency.
   2227     // It is a set of AffixPatternsForCurrency,
   2228     // each element of the set saves the negative prefix pattern,
   2229     // negative suffix pattern, positive prefix pattern,
   2230     // and positive suffix  pattern of a pattern.
   2231     // It is used for currency mixed style parsing.
   2232     // It is actually is a set.
   2233     // The set contains the default currency pattern from the locale,
   2234     // and the currency plural patterns.
   2235     // Since it is a set, it does not contain duplicated items.
   2236     // For example, if 2 currency plural patterns are the same, only one pattern
   2237     // is included in the set. When parsing, we do not check whether the plural
   2238     // count match or not.
   2239     Hashtable* fAffixPatternsForCurrency;
   2240 
   2241     // Information needed for DecimalFormat to format/parse currency plural.
   2242     CurrencyPluralInfo* fCurrencyPluralInfo;
   2243 
   2244 #if UCONFIG_HAVE_PARSEALLINPUT
   2245     UNumberFormatAttributeValue fParseAllInput;
   2246 #endif
   2247 
   2248     // Decimal Format Static Sets singleton.
   2249     const DecimalFormatStaticSets *fStaticSets;
   2250 
   2251 protected:
   2252 
   2253 #ifndef U_HIDE_INTERNAL_API
   2254     /**
   2255      * Rounds a value according to the rules of this object.
   2256      * @internal
   2257      */
   2258     DigitList& _round(const DigitList& number, DigitList& adjustedNum, UBool& isNegative, UErrorCode& status) const;
   2259 #endif  /* U_HIDE_INTERNAL_API */
   2260 
   2261     /**
   2262      * Returns the currency in effect for this formatter.  Subclasses
   2263      * should override this method as needed.  Unlike getCurrency(),
   2264      * this method should never return "".
   2265      * @result output parameter for null-terminated result, which must
   2266      * have a capacity of at least 4
   2267      * @internal
   2268      */
   2269     virtual void getEffectiveCurrency(UChar* result, UErrorCode& ec) const;
   2270 
   2271   /** number of integer digits
   2272    * @stable ICU 2.4
   2273    */
   2274     static const int32_t  kDoubleIntegerDigits;
   2275   /** number of fraction digits
   2276    * @stable ICU 2.4
   2277    */
   2278     static const int32_t  kDoubleFractionDigits;
   2279 
   2280     /**
   2281      * When someone turns on scientific mode, we assume that more than this
   2282      * number of digits is due to flipping from some other mode that didn't
   2283      * restrict the maximum, and so we force 1 integer digit.  We don't bother
   2284      * to track and see if someone is using exponential notation with more than
   2285      * this number, it wouldn't make sense anyway, and this is just to make sure
   2286      * that someone turning on scientific mode with default settings doesn't
   2287      * end up with lots of zeroes.
   2288      * @stable ICU 2.8
   2289      */
   2290     static const int32_t  kMaxScientificIntegerDigits;
   2291 
   2292 };
   2293 
   2294 U_NAMESPACE_END
   2295 
   2296 #endif /* #if !UCONFIG_NO_FORMATTING */
   2297 
   2298 #endif // _DECIMFMT
   2299 //eof
   2300