tor-browser

decimfmt.h (89552B)

---

// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*
********************************************************************************
*   Copyright (C) 1997-2016, International Business Machines
*   Corporation and others.  All Rights Reserved.
********************************************************************************
*
* File DECIMFMT.H
*
* Modification History:
*
*   Date        Name        Description
*   02/19/97    aliu        Converted from java.
*   03/20/97    clhuang     Updated per C++ implementation.
*   04/03/97    aliu        Rewrote parsing and formatting completely, and
*                           cleaned up and debugged.  Actually works now.
*   04/17/97    aliu        Changed DigitCount to int per code review.
*   07/10/97    helena      Made ParsePosition a class and get rid of the function
*                           hiding problems.
*   09/09/97    aliu        Ported over support for exponential formats.
*   07/20/98    stephen     Changed documentation
*   01/30/13    emmons      Added Scaling methods
********************************************************************************
*/

#ifndef DECIMFMT_H
#define DECIMFMT_H

#include "unicode/utypes.h"

#if U_SHOW_CPLUSPLUS_API

/**
* \file
* \brief C++ API: Compatibility APIs for decimal formatting.
*/

#if !UCONFIG_NO_FORMATTING

#include "unicode/dcfmtsym.h"
#include "unicode/numfmt.h"
#include "unicode/locid.h"
#include "unicode/fpositer.h"
#include "unicode/stringpiece.h"
#include "unicode/curramt.h"
#include "unicode/enumset.h"

U_NAMESPACE_BEGIN

class CurrencyPluralInfo;
class CompactDecimalFormat;

namespace number {
class LocalizedNumberFormatter;
namespace impl {
class DecimalQuantity;
struct DecimalFormatFields;
class UFormattedNumberData;
}
}

namespace numparse::impl {
class NumberParserImpl;
}

/**
* **IMPORTANT:** New users are strongly encouraged to see if
* numberformatter.h fits their use case.  Although not deprecated, this header
* is provided for backwards compatibility only.
*
* DecimalFormat is a concrete subclass of NumberFormat that formats decimal
* numbers. It has a variety of features designed to make it possible to parse
* and format numbers in any locale, including support for Western, Arabic, or
* Indic digits.  It also supports different flavors of numbers, including
* integers ("123"), fixed-point numbers ("123.4"), scientific notation
* ("1.23E4"), percentages ("12%"), and currency amounts ("$123", "USD123",
* "123 US dollars").  All of these flavors can be easily localized.
*
* To obtain a NumberFormat for a specific locale (including the default
* locale) call one of NumberFormat's factory methods such as
* createInstance(). Do not call the DecimalFormat constructors directly, unless
* you know what you are doing, since the NumberFormat factory methods may
* return subclasses other than DecimalFormat.
*
* **Example Usage**
*
* \code
*     // Normally we would have a GUI with a menu for this
*     int32_t locCount;
*     const Locale* locales = NumberFormat::getAvailableLocales(locCount);
*
*     double myNumber = -1234.56;
*     UErrorCode success = U_ZERO_ERROR;
*     NumberFormat* form;
*
*     // Print out a number with the localized number, currency and percent
*     // format for each locale.
*     UnicodeString countryName;
*     UnicodeString displayName;
*     UnicodeString str;
*     UnicodeString pattern;
*     Formattable fmtable;
*     for (int32_t j = 0; j < 3; ++j) {
*         cout << endl << "FORMAT " << j << endl;
*         for (int32_t i = 0; i < locCount; ++i) {
*             if (locales[i].getCountry(countryName).size() == 0) {
*                 // skip language-only
*                 continue;
*             }
*             switch (j) {
*             case 0:
*                 form = NumberFormat::createInstance(locales[i], success ); break;
*             case 1:
*                 form = NumberFormat::createCurrencyInstance(locales[i], success ); break;
*             default:
*                 form = NumberFormat::createPercentInstance(locales[i], success ); break;
*             }
*             if (form) {
*                 str.remove();
*                 pattern = ((DecimalFormat*)form)->toPattern(pattern);
*                 cout << locales[i].getDisplayName(displayName) << ": " << pattern;
*                 cout << "  ->  " << form->format(myNumber,str) << endl;
*                 form->parse(form->format(myNumber,str), fmtable, success);
*                 delete form;
*             }
*         }
*     }
* \endcode
*
* **Another example use createInstance(style)**
*
* \code
* // Print out a number using the localized number, currency,
* // percent, scientific, integer, iso currency, and plural currency
* // format for each locale</strong>
* Locale* locale = new Locale("en", "US");
* double myNumber = 1234.56;
* UErrorCode success = U_ZERO_ERROR;
* UnicodeString str;
* Formattable fmtable;
* for (int j=NumberFormat::kNumberStyle;
*      j<=NumberFormat::kPluralCurrencyStyle;
*      ++j) {
*     NumberFormat* form = NumberFormat::createInstance(locale, j, success);
*     str.remove();
*     cout << "format result " << form->format(myNumber, str) << endl;
*     format->parse(form->format(myNumber, str), fmtable, success);
*     delete form;
* }
* \endcode
*
*
* <p><strong>Patterns</strong>
*
* <p>A DecimalFormat consists of a <em>pattern</em> and a set of
* <em>symbols</em>.  The pattern may be set directly using
* applyPattern(), or indirectly using other API methods which
* manipulate aspects of the pattern, such as the minimum number of integer
* digits.  The symbols are stored in a DecimalFormatSymbols
* object.  When using the NumberFormat factory methods, the
* pattern and symbols are read from ICU's locale data.
*
* <p><strong>Special Pattern Characters</strong>
*
* <p>Many characters in a pattern are taken literally; they are matched during
* parsing and output unchanged during formatting.  Special characters, on the
* other hand, stand for other characters, strings, or classes of characters.
* For example, the '#' character is replaced by a localized digit.  Often the
* replacement character is the same as the pattern character; in the U.S. locale,
* the ',' grouping character is replaced by ','.  However, the replacement is
* still happening, and if the symbols are modified, the grouping character
* changes.  Some special characters affect the behavior of the formatter by
* their presence; for example, if the percent character is seen, then the
* value is multiplied by 100 before being displayed.
*
* <p>To insert a special character in a pattern as a literal, that is, without
* any special meaning, the character must be quoted.  There are some exceptions to
* this which are noted below.
*
* <p>The characters listed here are used in non-localized patterns.  Localized
* patterns use the corresponding characters taken from this formatter's
* DecimalFormatSymbols object instead, and these characters lose
* their special status.  Two exceptions are the currency sign and quote, which
* are not localized.
*
* <table border=0 cellspacing=3 cellpadding=0>
*   <tr bgcolor="#ccccff">
*     <td align=left><strong>Symbol</strong>
*     <td align=left><strong>Location</strong>
*     <td align=left><strong>Localized?</strong>
*     <td align=left><strong>Meaning</strong>
*   <tr valign=top>
*     <td><code>0</code>
*     <td>Number
*     <td>Yes
*     <td>Digit
*   <tr valign=top bgcolor="#eeeeff">
*     <td><code>1-9</code>
*     <td>Number
*     <td>Yes
*     <td>'1' through '9' indicate rounding.
*   <tr valign=top>
*     <td><code>\htmlonly&#x40;\endhtmlonly</code> <!--doxygen doesn't like @-->
*     <td>Number
*     <td>No
*     <td>Significant digit
*   <tr valign=top bgcolor="#eeeeff">
*     <td><code>#</code>
*     <td>Number
*     <td>Yes
*     <td>Digit, zero shows as absent
*   <tr valign=top>
*     <td><code>.</code>
*     <td>Number
*     <td>Yes
*     <td>Decimal separator or monetary decimal separator
*   <tr valign=top bgcolor="#eeeeff">
*     <td><code>-</code>
*     <td>Number
*     <td>Yes
*     <td>Minus sign
*   <tr valign=top>
*     <td><code>,</code>
*     <td>Number
*     <td>Yes
*     <td>Grouping separator
*   <tr valign=top bgcolor="#eeeeff">
*     <td><code>E</code>
*     <td>Number
*     <td>Yes
*     <td>Separates mantissa and exponent in scientific notation.
*         <em>Need not be quoted in prefix or suffix.</em>
*   <tr valign=top>
*     <td><code>+</code>
*     <td>Exponent
*     <td>Yes
*     <td>Prefix positive exponents with localized plus sign.
*         <em>Need not be quoted in prefix or suffix.</em>
*   <tr valign=top bgcolor="#eeeeff">
*     <td><code>;</code>
*     <td>Subpattern boundary
*     <td>Yes
*     <td>Separates positive and negative subpatterns
*   <tr valign=top>
*     <td><code>\%</code>
*     <td>Prefix or suffix
*     <td>Yes
*     <td>Multiply by 100 and show as percentage
*   <tr valign=top bgcolor="#eeeeff">
*     <td><code>\\u2030</code>
*     <td>Prefix or suffix
*     <td>Yes
*     <td>Multiply by 1000 and show as per mille
*   <tr valign=top>
*     <td><code>\htmlonly&curren;\endhtmlonly</code> (<code>\\u00A4</code>)
*     <td>Prefix or suffix
*     <td>No
*     <td>Currency sign, replaced by currency symbol.  If
*         doubled, replaced by international currency symbol.
*         If tripled, replaced by currency plural names, for example,
*         "US dollar" or "US dollars" for America.
*         If present in a pattern, the monetary decimal separator
*         is used instead of the decimal separator.
*   <tr valign=top bgcolor="#eeeeff">
*     <td><code>'</code>
*     <td>Prefix or suffix
*     <td>No
*     <td>Used to quote special characters in a prefix or suffix,
*         for example, <code>"'#'#"</code> formats 123 to
*         <code>"#123"</code>.  To create a single quote
*         itself, use two in a row: <code>"# o''clock"</code>.
*   <tr valign=top>
*     <td><code>*</code>
*     <td>Prefix or suffix boundary
*     <td>Yes
*     <td>Pad escape, precedes pad character
* </table>
*
* <p>A DecimalFormat pattern contains a positive and negative
* subpattern, for example, "#,##0.00;(#,##0.00)".  Each subpattern has a
* prefix, a numeric part, and a suffix.  If there is no explicit negative
* subpattern, the negative subpattern is the localized minus sign prefixed to the
* positive subpattern. That is, "0.00" alone is equivalent to "0.00;-0.00".  If there
* is an explicit negative subpattern, it serves only to specify the negative
* prefix and suffix; the number of digits, minimal digits, and other
* characteristics are ignored in the negative subpattern. That means that
* "#,##0.0#;(#)" has precisely the same result as "#,##0.0#;(#,##0.0#)".
*
* <p>The prefixes, suffixes, and various symbols used for infinity, digits,
* thousands separators, decimal separators, etc. may be set to arbitrary
* values, and they will appear properly during formatting.  However, care must
* be taken that the symbols and strings do not conflict, or parsing will be
* unreliable.  For example, either the positive and negative prefixes or the
* suffixes must be distinct for parse() to be able
* to distinguish positive from negative values.  Another example is that the
* decimal separator and thousands separator should be distinct characters, or
* parsing will be impossible.
*
* <p>The <em>grouping separator</em> is a character that separates clusters of
* integer digits to make large numbers more legible.  It commonly used for
* thousands, but in some locales it separates ten-thousands.  The <em>grouping
* size</em> is the number of digits between the grouping separators, such as 3
* for "100,000,000" or 4 for "1 0000 0000". There are actually two different
* grouping sizes: One used for the least significant integer digits, the
* <em>primary grouping size</em>, and one used for all others, the
* <em>secondary grouping size</em>.  In most locales these are the same, but
* sometimes they are different. For example, if the primary grouping interval
* is 3, and the secondary is 2, then this corresponds to the pattern
* "#,##,##0", and the number 123456789 is formatted as "12,34,56,789".  If a
* pattern contains multiple grouping separators, the interval between the last
* one and the end of the integer defines the primary grouping size, and the
* interval between the last two defines the secondary grouping size. All others
* are ignored, so "#,##,###,####" == "###,###,####" == "##,#,###,####".
*
* <p>Illegal patterns, such as "#.#.#" or "#.###,###", will cause
* DecimalFormat to set a failing UErrorCode.
*
* <p><strong>Pattern BNF</strong>
*
* <pre>
* pattern    := subpattern (';' subpattern)?
* subpattern := prefix? number exponent? suffix?
* number     := (integer ('.' fraction)?) | sigDigits
* prefix     := '\\u0000'..'\\uFFFD' - specialCharacters
* suffix     := '\\u0000'..'\\uFFFD' - specialCharacters
* integer    := '#'* '0'* '0'
* fraction   := '0'* '#'*
* sigDigits  := '#'* '@' '@'* '#'*
* exponent   := 'E' '+'? '0'* '0'
* padSpec    := '*' padChar
* padChar    := '\\u0000'..'\\uFFFD' - quote
* &nbsp;
* Notation:
*   X*       0 or more instances of X
*   X?       0 or 1 instances of X
*   X|Y      either X or Y
*   C..D     any character from C up to D, inclusive
*   S-T      characters in S, except those in T
* </pre>
* The first subpattern is for positive numbers. The second (optional)
* subpattern is for negative numbers.
*
* <p>Not indicated in the BNF syntax above:
*
* <ul><li>The grouping separator ',' can occur inside the integer and
* sigDigits elements, between any two pattern characters of that
* element, as long as the integer or sigDigits element is not
* followed by the exponent element.
*
* <li>Two grouping intervals are recognized: That between the
*     decimal point and the first grouping symbol, and that
*     between the first and second grouping symbols. These
*     intervals are identical in most locales, but in some
*     locales they differ. For example, the pattern
*     &quot;#,##,###&quot; formats the number 123456789 as
*     &quot;12,34,56,789&quot;.</li>
*
* <li>The pad specifier <code>padSpec</code> may appear before the prefix,
* after the prefix, before the suffix, after the suffix, or not at all.
*
* <li>In place of '0', the digits '1' through '9' may be used to
* indicate a rounding increment.
* </ul>
*
* <p><strong>Parsing</strong>
*
* <p>DecimalFormat parses all Unicode characters that represent
* decimal digits, as defined by u_charDigitValue().  In addition,
* DecimalFormat also recognizes as digits the ten consecutive
* characters starting with the localized zero digit defined in the
* DecimalFormatSymbols object.  During formatting, the
* DecimalFormatSymbols-based digits are output.
*
* <p>During parsing, grouping separators are ignored if in lenient mode;
* otherwise, if present, they must be in appropriate positions.
*
* <p>For currency parsing, the formatter is able to parse every currency
* style formats no matter which style the formatter is constructed with.
* For example, a formatter instance gotten from
* NumberFormat.getInstance(ULocale, NumberFormat.CURRENCYSTYLE) can parse
* formats such as "USD1.00" and "3.00 US dollars".
*
* <p>If parse(UnicodeString&,Formattable&,ParsePosition&)
* fails to parse a string, it leaves the parse position unchanged.
* The convenience method parse(UnicodeString&,Formattable&,UErrorCode&)
* indicates parse failure by setting a failing
* UErrorCode.
*
* <p><strong>Formatting</strong>
*
* <p>Formatting is guided by several parameters, all of which can be
* specified either using a pattern or using the API.  The following
* description applies to formats that do not use <a href="#sci">scientific
* notation</a> or <a href="#sigdig">significant digits</a>.
*
* <ul><li>If the number of actual integer digits exceeds the
* <em>maximum integer digits</em>, then only the least significant
* digits are shown.  For example, 1997 is formatted as "97" if the
* maximum integer digits is set to 2.
*
* <li>If the number of actual integer digits is less than the
* <em>minimum integer digits</em>, then leading zeros are added.  For
* example, 1997 is formatted as "01997" if the minimum integer digits
* is set to 5.
*
* <li>If the number of actual fraction digits exceeds the <em>maximum
* fraction digits</em>, then rounding is performed to the
* maximum fraction digits.  For example, 0.125 is formatted as "0.12"
* if the maximum fraction digits is 2.  This behavior can be changed
* by specifying a rounding increment and/or a rounding mode.
*
* <li>If the number of actual fraction digits is less than the
* <em>minimum fraction digits</em>, then trailing zeros are added.
* For example, 0.125 is formatted as "0.1250" if the minimum fraction
* digits is set to 4.
*
* <li>Trailing fractional zeros are not displayed if they occur
* <em>j</em> positions after the decimal, where <em>j</em> is less
* than the maximum fraction digits. For example, 0.10004 is
* formatted as "0.1" if the maximum fraction digits is four or less.
* </ul>
*
* <p><strong>Special Values</strong>
*
* <p><code>NaN</code> is represented as a single character, typically
* <code>\\uFFFD</code>.  This character is determined by the
* DecimalFormatSymbols object.  This is the only value for which
* the prefixes and suffixes are not used.
*
* <p>Infinity is represented as a single character, typically
* <code>\\u221E</code>, with the positive or negative prefixes and suffixes
* applied.  The infinity character is determined by the
* DecimalFormatSymbols object.
*
* <a name="sci"><strong>Scientific Notation</strong></a>
*
* <p>Numbers in scientific notation are expressed as the product of a mantissa
* and a power of ten, for example, 1234 can be expressed as 1.234 x 10<sup>3</sup>. The
* mantissa is typically in the half-open interval [1.0, 10.0) or sometimes [0.0, 1.0),
* but it need not be.  DecimalFormat supports arbitrary mantissas.
* DecimalFormat can be instructed to use scientific
* notation through the API or through the pattern.  In a pattern, the exponent
* character immediately followed by one or more digit characters indicates
* scientific notation.  Example: "0.###E0" formats the number 1234 as
* "1.234E3".
*
* <ul>
* <li>The number of digit characters after the exponent character gives the
* minimum exponent digit count.  There is no maximum.  Negative exponents are
* formatted using the localized minus sign, <em>not</em> the prefix and suffix
* from the pattern.  This allows patterns such as "0.###E0 m/s".  To prefix
* positive exponents with a localized plus sign, specify '+' between the
* exponent and the digits: "0.###E+0" will produce formats "1E+1", "1E+0",
* "1E-1", etc.  (In localized patterns, use the localized plus sign rather than
* '+'.)
*
* <li>The minimum number of integer digits is achieved by adjusting the
* exponent.  Example: 0.00123 formatted with "00.###E0" yields "12.3E-4".  This
* only happens if there is no maximum number of integer digits.  If there is a
* maximum, then the minimum number of integer digits is fixed at one.
*
* <li>The maximum number of integer digits, if present, specifies the exponent
* grouping.  The most common use of this is to generate <em>engineering
* notation</em>, in which the exponent is a multiple of three, e.g.,
* "##0.###E0".  The number 12345 is formatted using "##0.####E0" as "12.345E3".
*
* <li>When using scientific notation, the formatter controls the
* digit counts using significant digits logic.  The maximum number of
* significant digits limits the total number of integer and fraction
* digits that will be shown in the mantissa; it does not affect
* parsing.  For example, 12345 formatted with "##0.##E0" is "12.3E3".
* See the section on significant digits for more details.
*
* <li>The number of significant digits shown is determined as
* follows: If areSignificantDigitsUsed() returns false, then the
* minimum number of significant digits shown is one, and the maximum
* number of significant digits shown is the sum of the <em>minimum
* integer</em> and <em>maximum fraction</em> digits, and is
* unaffected by the maximum integer digits.  If this sum is zero,
* then all significant digits are shown.  If
* areSignificantDigitsUsed() returns true, then the significant digit
* counts are specified by getMinimumSignificantDigits() and
* getMaximumSignificantDigits().  In this case, the number of
* integer digits is fixed at one, and there is no exponent grouping.
*
* <li>Exponential patterns may not contain grouping separators.
* </ul>
*
* <a name="sigdig"><strong>Significant Digits</strong></a>
*
* <code>DecimalFormat</code> has two ways of controlling how many
* digits are shows: (a) significant digits counts, or (b) integer and
* fraction digit counts.  Integer and fraction digit counts are
* described above.  When a formatter is using significant digits
* counts, the number of integer and fraction digits is not specified
* directly, and the formatter settings for these counts are ignored.
* Instead, the formatter uses however many integer and fraction
* digits are required to display the specified number of significant
* digits.  Examples:
*
* <table border=0 cellspacing=3 cellpadding=0>
*   <tr bgcolor="#ccccff">
*     <td align=left>Pattern
*     <td align=left>Minimum significant digits
*     <td align=left>Maximum significant digits
*     <td align=left>Number
*     <td align=left>Output of format()
*   <tr valign=top>
*     <td><code>\@\@\@</code>
*     <td>3
*     <td>3
*     <td>12345
*     <td><code>12300</code>
*   <tr valign=top bgcolor="#eeeeff">
*     <td><code>\@\@\@</code>
*     <td>3
*     <td>3
*     <td>0.12345
*     <td><code>0.123</code>
*   <tr valign=top>
*     <td><code>\@\@##</code>
*     <td>2
*     <td>4
*     <td>3.14159
*     <td><code>3.142</code>
*   <tr valign=top bgcolor="#eeeeff">
*     <td><code>\@\@##</code>
*     <td>2
*     <td>4
*     <td>1.23004
*     <td><code>1.23</code>
* </table>
*
* <ul>
* <li>Significant digit counts may be expressed using patterns that
* specify a minimum and maximum number of significant digits.  These
* are indicated by the <code>'@'</code> and <code>'#'</code>
* characters.  The minimum number of significant digits is the number
* of <code>'@'</code> characters.  The maximum number of significant
* digits is the number of <code>'@'</code> characters plus the number
* of <code>'#'</code> characters following on the right.  For
* example, the pattern <code>"@@@"</code> indicates exactly 3
* significant digits.  The pattern <code>"@##"</code> indicates from
* 1 to 3 significant digits.  Trailing zero digits to the right of
* the decimal separator are suppressed after the minimum number of
* significant digits have been shown.  For example, the pattern
* <code>"@##"</code> formats the number 0.1203 as
* <code>"0.12"</code>.
*
* <li>If a pattern uses significant digits, it may not contain a
* decimal separator, nor the <code>'0'</code> pattern character.
* Patterns such as <code>"@00"</code> or <code>"@.###"</code> are
* disallowed.
*
* <li>Any number of <code>'#'</code> characters may be prepended to
* the left of the leftmost <code>'@'</code> character.  These have no
* effect on the minimum and maximum significant digits counts, but
* may be used to position grouping separators.  For example,
* <code>"#,#@#"</code> indicates a minimum of one significant digits,
* a maximum of two significant digits, and a grouping size of three.
*
* <li>In order to enable significant digits formatting, use a pattern
* containing the <code>'@'</code> pattern character.  Alternatively,
* call setSignificantDigitsUsed(true).
*
* <li>In order to disable significant digits formatting, use a
* pattern that does not contain the <code>'@'</code> pattern
* character. Alternatively, call setSignificantDigitsUsed(false).
*
* <li>The number of significant digits has no effect on parsing.
*
* <li>Significant digits may be used together with exponential notation. Such
* patterns are equivalent to a normal exponential pattern with a minimum and
* maximum integer digit count of one, a minimum fraction digit count of
* <code>getMinimumSignificantDigits() - 1</code>, and a maximum fraction digit
* count of <code>getMaximumSignificantDigits() - 1</code>. For example, the
* pattern <code>"@@###E0"</code> is equivalent to <code>"0.0###E0"</code>.
*
* <li>If significant digits are in use, then the integer and fraction
* digit counts, as set via the API, are ignored.  If significant
* digits are not in use, then the significant digit counts, as set via
* the API, are ignored.
*
* </ul>
*
* <p><strong>Padding</strong>
*
* <p>DecimalFormat supports padding the result of
* format() to a specific width.  Padding may be specified either
* through the API or through the pattern syntax.  In a pattern the pad escape
* character, followed by a single pad character, causes padding to be parsed
* and formatted.  The pad escape character is '*' in unlocalized patterns, and
* can be localized using DecimalFormatSymbols::setSymbol() with a
* DecimalFormatSymbols::kPadEscapeSymbol
* selector.  For example, <code>"$*x#,##0.00"</code> formats 123 to
* <code>"$xx123.00"</code>, and 1234 to <code>"$1,234.00"</code>.
*
* <ul>
* <li>When padding is in effect, the width of the positive subpattern,
* including prefix and suffix, determines the format width.  For example, in
* the pattern <code>"* #0 o''clock"</code>, the format width is 10.
*
* <li>The width is counted in 16-bit code units (char16_ts).
*
* <li>Some parameters which usually do not matter have meaning when padding is
* used, because the pattern width is significant with padding.  In the pattern
* "* ##,##,#,##0.##", the format width is 14.  The initial characters "##,##,"
* do not affect the grouping size or maximum integer digits, but they do affect
* the format width.
*
* <li>Padding may be inserted at one of four locations: before the prefix,
* after the prefix, before the suffix, or after the suffix.  If padding is
* specified in any other location, applyPattern()
* sets a failing UErrorCode.  If there is no prefix,
* before the prefix and after the prefix are equivalent, likewise for the
* suffix.
*
* <li>When specified in a pattern, the 32-bit code point immediately
* following the pad escape is the pad character. This may be any character,
* including a special pattern character. That is, the pad escape
* <em>escapes</em> the following character. If there is no character after
* the pad escape, then the pattern is illegal.
*
* </ul>
*
* <p><strong>Rounding</strong>
*
* <p>DecimalFormat supports rounding to a specific increment.  For
* example, 1230 rounded to the nearest 50 is 1250.  1.234 rounded to the
* nearest 0.65 is 1.3.  The rounding increment may be specified through the API
* or in a pattern.  To specify a rounding increment in a pattern, include the
* increment in the pattern itself.  "#,#50" specifies a rounding increment of
* 50.  "#,##0.05" specifies a rounding increment of 0.05.
*
* <p>In the absence of an explicit rounding increment numbers are
* rounded to their formatted width.
*
* <ul>
* <li>Rounding only affects the string produced by formatting.  It does
* not affect parsing or change any numerical values.
*
* <li>A <em>rounding mode</em> determines how values are rounded; see
* DecimalFormat::ERoundingMode.  The default rounding mode is
* DecimalFormat::kRoundHalfEven.  The rounding mode can only be set
* through the API; it can not be set with a pattern.
*
* <li>Some locales use rounding in their currency formats to reflect the
* smallest currency denomination.
*
* <li>In a pattern, digits '1' through '9' specify rounding, but otherwise
* behave identically to digit '0'.
* </ul>
*
* <p><strong>Synchronization</strong>
*
* <p>DecimalFormat objects are not synchronized.  Multiple
* threads should not access one formatter concurrently.
*
* <p><strong>Subclassing</strong>
*
* <p><em>User subclasses are not supported.</em> While clients may write
* subclasses, such code will not necessarily work and will not be
* guaranteed to work stably from release to release.
*/
class U_I18N_API DecimalFormat : public NumberFormat {
 public:
   /**
    * Pad position.
    * @stable ICU 2.4
    */
   enum EPadPosition {
       kPadBeforePrefix, kPadAfterPrefix, kPadBeforeSuffix, kPadAfterSuffix
   };

   /**
    * Create a DecimalFormat using the default pattern and symbols
    * for the default locale. This is a convenient way to obtain a
    * DecimalFormat when internationalization is not the main concern.
    * <P>
    * To obtain standard formats for a given locale, use the factory methods
    * on NumberFormat such as createInstance. These factories will
    * return the most appropriate sub-class of NumberFormat for a given
    * locale.
    * <p>
    * <strong>NOTE:</strong> New users are strongly encouraged to use
    * #icu::number::NumberFormatter instead of DecimalFormat.
    * @param status    Output param set to success/failure code. If the
    *                  pattern is invalid this will be set to a failure code.
    * @stable ICU 2.0
    */
   DecimalFormat(UErrorCode& status);

   /**
    * Create a DecimalFormat from the given pattern and the symbols
    * for the default locale. This is a convenient way to obtain a
    * DecimalFormat when internationalization is not the main concern.
    * <P>
    * To obtain standard formats for a given locale, use the factory methods
    * on NumberFormat such as createInstance. These factories will
    * return the most appropriate sub-class of NumberFormat for a given
    * locale.
    * <p>
    * <strong>NOTE:</strong> New users are strongly encouraged to use
    * #icu::number::NumberFormatter instead of DecimalFormat.
    * @param pattern   A non-localized pattern string.
    * @param status    Output param set to success/failure code. If the
    *                  pattern is invalid this will be set to a failure code.
    * @stable ICU 2.0
    */
   DecimalFormat(const UnicodeString& pattern, UErrorCode& status);

   /**
    * Create a DecimalFormat from the given pattern and symbols.
    * Use this constructor when you need to completely customize the
    * behavior of the format.
    * <P>
    * To obtain standard formats for a given
    * locale, use the factory methods on NumberFormat such as
    * createInstance or createCurrencyInstance. If you need only minor adjustments
    * to a standard format, you can modify the format returned by
    * a NumberFormat factory method.
    * <p>
    * <strong>NOTE:</strong> New users are strongly encouraged to use
    * #icu::number::NumberFormatter instead of DecimalFormat.
    *
    * @param pattern           a non-localized pattern string
    * @param symbolsToAdopt    the set of symbols to be used.  The caller should not
    *                          delete this object after making this call.
    * @param status            Output param set to success/failure code. If the
    *                          pattern is invalid this will be set to a failure code.
    * @stable ICU 2.0
    */
   DecimalFormat(const UnicodeString& pattern, DecimalFormatSymbols* symbolsToAdopt, UErrorCode& status);

#ifndef U_HIDE_INTERNAL_API

   /**
    * This API is for ICU use only.
    * Create a DecimalFormat from the given pattern, symbols, and style.
    *
    * @param pattern           a non-localized pattern string
    * @param symbolsToAdopt    the set of symbols to be used.  The caller should not
    *                          delete this object after making this call.
    * @param style             style of decimal format
    * @param status            Output param set to success/failure code. If the
    *                          pattern is invalid this will be set to a failure code.
    * @internal
    */
   DecimalFormat(const UnicodeString& pattern, DecimalFormatSymbols* symbolsToAdopt,
                 UNumberFormatStyle style, UErrorCode& status);

#if UCONFIG_HAVE_PARSEALLINPUT

   /**
    * @internal
    */
   void setParseAllInput(UNumberFormatAttributeValue value);

#endif

#endif  /* U_HIDE_INTERNAL_API */

 private:

   /**
    * Internal constructor for DecimalFormat; sets up internal fields. All public constructors should
    * call this constructor.
    */
   DecimalFormat(const DecimalFormatSymbols* symbolsToAdopt, UErrorCode& status);

 public:

   /**
    * Set an integer attribute on this DecimalFormat.
    * May return U_UNSUPPORTED_ERROR if this instance does not support
    * the specified attribute.
    * @param attr the attribute to set
    * @param newValue new value
    * @param status the error type
    * @return *this - for chaining (example: format.setAttribute(...).setAttribute(...) )
    * @stable ICU 51
    */
   virtual DecimalFormat& setAttribute(UNumberFormatAttribute attr, int32_t newValue, UErrorCode& status);

   /**
    * Get an integer
    * May return U_UNSUPPORTED_ERROR if this instance does not support
    * the specified attribute.
    * @param attr the attribute to set
    * @param status the error type
    * @return the attribute value. Undefined if there is an error.
    * @stable ICU 51
    */
   virtual int32_t getAttribute(UNumberFormatAttribute attr, UErrorCode& status) const;


   /**
    * Set whether or not grouping will be used in this format.
    * @param newValue    True, grouping will be used in this format.
    * @see getGroupingUsed
    * @stable ICU 53
    */
   void setGroupingUsed(UBool newValue) override;

   /**
    * Sets whether or not numbers should be parsed as integers only.
    * @param value    set True, this format will parse numbers as integers
    *                 only.
    * @see isParseIntegerOnly
    * @stable ICU 53
    */
   void setParseIntegerOnly(UBool value) override;

   /**
    * Sets whether lenient parsing should be enabled (it is off by default).
    *
    * @param enable \c true if lenient parsing should be used,
    *               \c false otherwise.
    * @stable ICU 4.8
    */
   void setLenient(UBool enable) override;

   /**
    * Create a DecimalFormat from the given pattern and symbols.
    * Use this constructor when you need to completely customize the
    * behavior of the format.
    * <P>
    * To obtain standard formats for a given
    * locale, use the factory methods on NumberFormat such as
    * createInstance or createCurrencyInstance. If you need only minor adjustments
    * to a standard format, you can modify the format returned by
    * a NumberFormat factory method.
    * <p>
    * <strong>NOTE:</strong> New users are strongly encouraged to use
    * #icu::number::NumberFormatter instead of DecimalFormat.
    *
    * @param pattern           a non-localized pattern string
    * @param symbolsToAdopt    the set of symbols to be used.  The caller should not
    *                          delete this object after making this call.
    * @param parseError        Output param to receive errors occurred during parsing
    * @param status            Output param set to success/failure code. If the
    *                          pattern is invalid this will be set to a failure code.
    * @stable ICU 2.0
    */
   DecimalFormat(const UnicodeString& pattern, DecimalFormatSymbols* symbolsToAdopt,
                 UParseError& parseError, UErrorCode& status);

   /**
    * Create a DecimalFormat from the given pattern and symbols.
    * Use this constructor when you need to completely customize the
    * behavior of the format.
    * <P>
    * To obtain standard formats for a given
    * locale, use the factory methods on NumberFormat such as
    * createInstance or createCurrencyInstance. If you need only minor adjustments
    * to a standard format, you can modify the format returned by
    * a NumberFormat factory method.
    * <p>
    * <strong>NOTE:</strong> New users are strongly encouraged to use
    * #icu::number::NumberFormatter instead of DecimalFormat.
    *
    * @param pattern           a non-localized pattern string
    * @param symbols   the set of symbols to be used
    * @param status            Output param set to success/failure code. If the
    *                          pattern is invalid this will be set to a failure code.
    * @stable ICU 2.0
    */
   DecimalFormat(const UnicodeString& pattern, const DecimalFormatSymbols& symbols, UErrorCode& status);

   /**
    * Copy constructor.
    *
    * @param source    the DecimalFormat object to be copied from.
    * @stable ICU 2.0
    */
   DecimalFormat(const DecimalFormat& source);

   /**
    * Assignment operator.
    *
    * @param rhs    the DecimalFormat object to be copied.
    * @stable ICU 2.0
    */
   DecimalFormat& operator=(const DecimalFormat& rhs);

   /**
    * Destructor.
    * @stable ICU 2.0
    */
   ~DecimalFormat() override;

   /**
    * Clone this Format object polymorphically. The caller owns the
    * result and should delete it when done.
    *
    * @return    a polymorphic copy of this DecimalFormat.
    * @stable ICU 2.0
    */
   DecimalFormat* clone() const override;

   /**
    * Return true if the given Format objects are semantically equal.
    * Objects of different subclasses are considered unequal.
    *
    * @param other    the object to be compared with.
    * @return         true if the given Format objects are semantically equal.
    * @stable ICU 2.0
    */
   bool operator==(const Format& other) const override;


   using NumberFormat::format;

   /**
    * Format a double or long number using base-10 representation.
    *
    * @param number    The value to be formatted.
    * @param appendTo  Output parameter to receive result.
    *                  Result is appended to existing contents.
    * @param pos       On input: an alignment field, if desired.
    *                  On output: the offsets of the alignment field.
    * @return          Reference to 'appendTo' parameter.
    * @stable ICU 2.0
    */
   UnicodeString& format(double number, UnicodeString& appendTo, FieldPosition& pos) const override;

#ifndef U_HIDE_INTERNAL_API
   /**
    * Format a double or long number using base-10 representation.
    *
    * @param number    The value to be formatted.
    * @param appendTo  Output parameter to receive result.
    *                  Result is appended to existing contents.
    * @param pos       On input: an alignment field, if desired.
    *                  On output: the offsets of the alignment field.
    * @param status
    * @return          Reference to 'appendTo' parameter.
    * @internal
    */
   UnicodeString& format(double number, UnicodeString& appendTo, FieldPosition& pos,
                         UErrorCode& status) const override;
#endif  /* U_HIDE_INTERNAL_API */

   /**
    * Format a double or long number using base-10 representation.
    *
    * @param number    The value to be formatted.
    * @param appendTo  Output parameter to receive result.
    *                  Result is appended to existing contents.
    * @param posIter   On return, can be used to iterate over positions
    *                  of fields generated by this format call.
    *                  Can be nullptr.
    * @param status    Output param filled with success/failure status.
    * @return          Reference to 'appendTo' parameter.
    * @stable ICU 4.4
    */
   UnicodeString& format(double number, UnicodeString& appendTo, FieldPositionIterator* posIter,
                         UErrorCode& status) const override;

   /**
    * Format a long number using base-10 representation.
    *
    * @param number    The value to be formatted.
    * @param appendTo  Output parameter to receive result.
    *                  Result is appended to existing contents.
    * @param pos       On input: an alignment field, if desired.
    *                  On output: the offsets of the alignment field.
    * @return          Reference to 'appendTo' parameter.
    * @stable ICU 2.0
    */
   UnicodeString& format(int32_t number, UnicodeString& appendTo, FieldPosition& pos) const override;

#ifndef U_HIDE_INTERNAL_API
   /**
    * Format a long number using base-10 representation.
    *
    * @param number    The value to be formatted.
    * @param appendTo  Output parameter to receive result.
    *                  Result is appended to existing contents.
    * @param pos       On input: an alignment field, if desired.
    *                  On output: the offsets of the alignment field.
    * @param status    Output param filled with success/failure status.
    * @return          Reference to 'appendTo' parameter.
    * @internal
    */
   UnicodeString& format(int32_t number, UnicodeString& appendTo, FieldPosition& pos,
                         UErrorCode& status) const override;
#endif  /* U_HIDE_INTERNAL_API */

   /**
    * Format a long number using base-10 representation.
    *
    * @param number    The value to be formatted.
    * @param appendTo  Output parameter to receive result.
    *                  Result is appended to existing contents.
    * @param posIter   On return, can be used to iterate over positions
    *                  of fields generated by this format call.
    *                  Can be nullptr.
    * @param status    Output param filled with success/failure status.
    * @return          Reference to 'appendTo' parameter.
    * @stable ICU 4.4
    */
   UnicodeString& format(int32_t number, UnicodeString& appendTo, FieldPositionIterator* posIter,
                         UErrorCode& status) const override;

   /**
    * Format an int64 number using base-10 representation.
    *
    * @param number    The value to be formatted.
    * @param appendTo  Output parameter to receive result.
    *                  Result is appended to existing contents.
    * @param pos       On input: an alignment field, if desired.
    *                  On output: the offsets of the alignment field.
    * @return          Reference to 'appendTo' parameter.
    * @stable ICU 2.8
    */
   UnicodeString& format(int64_t number, UnicodeString& appendTo, FieldPosition& pos) const override;

#ifndef U_HIDE_INTERNAL_API
   /**
    * Format an int64 number using base-10 representation.
    *
    * @param number    The value to be formatted.
    * @param appendTo  Output parameter to receive result.
    *                  Result is appended to existing contents.
    * @param pos       On input: an alignment field, if desired.
    *                  On output: the offsets of the alignment field.
    * @param status    Output param filled with success/failure status.
    * @return          Reference to 'appendTo' parameter.
    * @internal
    */
   UnicodeString& format(int64_t number, UnicodeString& appendTo, FieldPosition& pos,
                         UErrorCode& status) const override;
#endif  /* U_HIDE_INTERNAL_API */

   /**
    * Format an int64 number using base-10 representation.
    *
    * @param number    The value to be formatted.
    * @param appendTo  Output parameter to receive result.
    *                  Result is appended to existing contents.
    * @param posIter   On return, can be used to iterate over positions
    *                  of fields generated by this format call.
    *                  Can be nullptr.
    * @param status    Output param filled with success/failure status.
    * @return          Reference to 'appendTo' parameter.
    * @stable ICU 4.4
    */
   UnicodeString& format(int64_t number, UnicodeString& appendTo, FieldPositionIterator* posIter,
                         UErrorCode& status) const override;

   /**
    * Format a decimal number.
    * The syntax of the unformatted number is a "numeric string"
    * as defined in the Decimal Arithmetic Specification, available at
    * http://speleotrove.com/decimal
    *
    * @param number    The unformatted number, as a string.
    * @param appendTo  Output parameter to receive result.
    *                  Result is appended to existing contents.
    * @param posIter   On return, can be used to iterate over positions
    *                  of fields generated by this format call.
    *                  Can be nullptr.
    * @param status    Output param filled with success/failure status.
    * @return          Reference to 'appendTo' parameter.
    * @stable ICU 4.4
    */
   UnicodeString& format(StringPiece number, UnicodeString& appendTo, FieldPositionIterator* posIter,
                         UErrorCode& status) const override;

#ifndef U_HIDE_INTERNAL_API

   /**
    * Format a decimal number.
    * The number is a DecimalQuantity wrapper onto a floating point decimal number.
    * The default implementation in NumberFormat converts the decimal number
    * to a double and formats that.
    *
    * @param number    The number, a DecimalQuantity format Decimal Floating Point.
    * @param appendTo  Output parameter to receive result.
    *                  Result is appended to existing contents.
    * @param posIter   On return, can be used to iterate over positions
    *                  of fields generated by this format call.
    * @param status    Output param filled with success/failure status.
    * @return          Reference to 'appendTo' parameter.
    * @internal
    */
   UnicodeString& format(const number::impl::DecimalQuantity& number, UnicodeString& appendTo,
                         FieldPositionIterator* posIter, UErrorCode& status) const override;

   /**
    * Format a decimal number.
    * The number is a DecimalQuantity wrapper onto a floating point decimal number.
    * The default implementation in NumberFormat converts the decimal number
    * to a double and formats that.
    *
    * @param number    The number, a DecimalQuantity format Decimal Floating Point.
    * @param appendTo  Output parameter to receive result.
    *                  Result is appended to existing contents.
    * @param pos       On input: an alignment field, if desired.
    *                  On output: the offsets of the alignment field.
    * @param status    Output param filled with success/failure status.
    * @return          Reference to 'appendTo' parameter.
    * @internal
    */
   UnicodeString& format(const number::impl::DecimalQuantity& number, UnicodeString& appendTo,
                         FieldPosition& pos, UErrorCode& status) const override;

#endif // U_HIDE_INTERNAL_API

   using NumberFormat::parse;

   /**
    * Parse the given string using this object's choices. The method
    * does string comparisons to try to find an optimal match.
    * If no object can be parsed, index is unchanged, and nullptr is
    * returned.  The result is returned as the most parsimonious
    * type of Formattable that will accommodate all of the
    * necessary precision.  For example, if the result is exactly 12,
    * it will be returned as a long.  However, if it is 1.5, it will
    * be returned as a double.
    *
    * @param text           The text to be parsed.
    * @param result         Formattable to be set to the parse result.
    *                       If parse fails, return contents are undefined.
    * @param parsePosition  The position to start parsing at on input.
    *                       On output, moved to after the last successfully
    *                       parse character. On parse failure, does not change.
    * @see Formattable
    * @stable ICU 2.0
    */
   void parse(const UnicodeString& text, Formattable& result,
              ParsePosition& parsePosition) const override;

   /**
    * Parses text from the given string as a currency amount.  Unlike
    * the parse() method, this method will attempt to parse a generic
    * currency name, searching for a match of this object's locale's
    * currency display names, or for a 3-letter ISO currency code.
    * This method will fail if this format is not a currency format,
    * that is, if it does not contain the currency pattern symbol
    * (U+00A4) in its prefix or suffix.
    *
    * @param text the string to parse
    * @param pos  input-output position; on input, the position within text
    *             to match; must have 0 <= pos.getIndex() < text.length();
    *             on output, the position after the last matched character.
    *             If the parse fails, the position in unchanged upon output.
    * @return     if parse succeeds, a pointer to a newly-created CurrencyAmount
    *             object (owned by the caller) containing information about
    *             the parsed currency; if parse fails, this is nullptr.
    * @stable ICU 49
    */
   CurrencyAmount* parseCurrency(const UnicodeString& text, ParsePosition& pos) const override;

   /**
    * Returns the decimal format symbols, which is generally not changed
    * by the programmer or user.
    * @return desired DecimalFormatSymbols
    * @see DecimalFormatSymbols
    * @stable ICU 2.0
    */
   virtual const DecimalFormatSymbols* getDecimalFormatSymbols() const;

   /**
    * Sets the decimal format symbols, which is generally not changed
    * by the programmer or user.
    * @param symbolsToAdopt DecimalFormatSymbols to be adopted.
    * @stable ICU 2.0
    */
   virtual void adoptDecimalFormatSymbols(DecimalFormatSymbols* symbolsToAdopt);

   /**
    * Sets the decimal format symbols, which is generally not changed
    * by the programmer or user.
    * @param symbols DecimalFormatSymbols.
    * @stable ICU 2.0
    */
   virtual void setDecimalFormatSymbols(const DecimalFormatSymbols& symbols);


   /**
    * Returns the currency plural format information,
    * which is generally not changed by the programmer or user.
    * @return desired CurrencyPluralInfo
    * @stable ICU 4.2
    */
   virtual const CurrencyPluralInfo* getCurrencyPluralInfo() const;

   /**
    * Sets the currency plural format information,
    * which is generally not changed by the programmer or user.
    * @param toAdopt CurrencyPluralInfo to be adopted.
    * @stable ICU 4.2
    */
   virtual void adoptCurrencyPluralInfo(CurrencyPluralInfo* toAdopt);

   /**
    * Sets the currency plural format information,
    * which is generally not changed by the programmer or user.
    * @param info Currency Plural Info.
    * @stable ICU 4.2
    */
   virtual void setCurrencyPluralInfo(const CurrencyPluralInfo& info);


   /**
    * Get the positive prefix.
    *
    * @param result    Output param which will receive the positive prefix.
    * @return          A reference to 'result'.
    * Examples: +123, $123, sFr123
    * @stable ICU 2.0
    */
   UnicodeString& getPositivePrefix(UnicodeString& result) const;

   /**
    * Set the positive prefix.
    *
    * @param newValue    the new value of the positive prefix to be set.
    * Examples: +123, $123, sFr123
    * @stable ICU 2.0
    */
   virtual void setPositivePrefix(const UnicodeString& newValue);

   /**
    * Get the negative prefix.
    *
    * @param result    Output param which will receive the negative prefix.
    * @return          A reference to 'result'.
    * Examples: -123, ($123) (with negative suffix), sFr-123
    * @stable ICU 2.0
    */
   UnicodeString& getNegativePrefix(UnicodeString& result) const;

   /**
    * Set the negative prefix.
    *
    * @param newValue    the new value of the negative prefix to be set.
    * Examples: -123, ($123) (with negative suffix), sFr-123
    * @stable ICU 2.0
    */
   virtual void setNegativePrefix(const UnicodeString& newValue);

   /**
    * Get the positive suffix.
    *
    * @param result    Output param which will receive the positive suffix.
    * @return          A reference to 'result'.
    * Example: 123%
    * @stable ICU 2.0
    */
   UnicodeString& getPositiveSuffix(UnicodeString& result) const;

   /**
    * Set the positive suffix.
    *
    * @param newValue    the new value of the positive suffix to be set.
    * Example: 123%
    * @stable ICU 2.0
    */
   virtual void setPositiveSuffix(const UnicodeString& newValue);

   /**
    * Get the negative suffix.
    *
    * @param result    Output param which will receive the negative suffix.
    * @return          A reference to 'result'.
    * Examples: -123%, ($123) (with positive suffixes)
    * @stable ICU 2.0
    */
   UnicodeString& getNegativeSuffix(UnicodeString& result) const;

   /**
    * Set the negative suffix.
    *
    * @param newValue    the new value of the negative suffix to be set.
    * Examples: 123%
    * @stable ICU 2.0
    */
   virtual void setNegativeSuffix(const UnicodeString& newValue);

   /**
    * Whether to show the plus sign on positive (non-negative) numbers; for example, "+12"
    *
    * For more control over sign display, use NumberFormatter.
    *
    * @return Whether the sign is shown on positive numbers and zero.
    * @stable ICU 64
    */
   UBool isSignAlwaysShown() const;

   /**
    * Set whether to show the plus sign on positive (non-negative) numbers; for example, "+12".
    *
    * For more control over sign display, use NumberFormatter.
    *
    * @param value true to always show a sign; false to hide the sign on positive numbers and zero.
    * @stable ICU 64
    */
   void setSignAlwaysShown(UBool value);

   /**
    * Get the multiplier for use in percent, permill, etc.
    * For a percentage, set the suffixes to have "%" and the multiplier to be 100.
    * (For Arabic, use arabic percent symbol).
    * For a permill, set the suffixes to have "\\u2031" and the multiplier to be 1000.
    *
    * The number may also be multiplied by a power of ten; see getMultiplierScale().
    *
    * @return    the multiplier for use in percent, permill, etc.
    * Examples: with 100, 1.23 -> "123", and "123" -> 1.23
    * @stable ICU 2.0
    */
   int32_t getMultiplier() const;

   /**
    * Set the multiplier for use in percent, permill, etc.
    * For a percentage, set the suffixes to have "%" and the multiplier to be 100.
    * (For Arabic, use arabic percent symbol).
    * For a permill, set the suffixes to have "\\u2031" and the multiplier to be 1000.
    *
    * This method only supports integer multipliers. To multiply by a non-integer, pair this
    * method with setMultiplierScale().
    *
    * @param newValue    the new value of the multiplier for use in percent, permill, etc.
    * Examples: with 100, 1.23 -> "123", and "123" -> 1.23
    * @stable ICU 2.0
    */
   virtual void setMultiplier(int32_t newValue);

   /**
    * Gets the power of ten by which number should be multiplied before formatting, which
    * can be combined with setMultiplier() to multiply by any arbitrary decimal value.
    *
    * A multiplier scale of 2 corresponds to multiplication by 100, and a multiplier scale
    * of -2 corresponds to multiplication by 0.01.
    *
    * This method is analogous to UNUM_SCALE in getAttribute.
    *
    * @return    the current value of the power-of-ten multiplier.
    * @stable ICU 62
    */
   int32_t getMultiplierScale() const;

   /**
    * Sets a power of ten by which number should be multiplied before formatting, which
    * can be combined with setMultiplier() to multiply by any arbitrary decimal value.
    *
    * A multiplier scale of 2 corresponds to multiplication by 100, and a multiplier scale
    * of -2 corresponds to multiplication by 0.01.
    *
    * For example, to multiply numbers by 0.5 before formatting, you can do:
    *
    * <pre>
    * df.setMultiplier(5);
    * df.setMultiplierScale(-1);
    * </pre>
    *
    * This method is analogous to UNUM_SCALE in setAttribute.
    *
    * @param newValue    the new value of the power-of-ten multiplier.
    * @stable ICU 62
    */
   void setMultiplierScale(int32_t newValue);

   /**
    * Get the rounding increment.
    * @return A positive rounding increment, or 0.0 if a custom rounding
    * increment is not in effect.
    * @see #setRoundingIncrement
    * @see #getRoundingMode
    * @see #setRoundingMode
    * @stable ICU 2.0
    */
   virtual double getRoundingIncrement() const;

   /**
    * Set the rounding increment.  In the absence of a rounding increment,
    *    numbers will be rounded to the number of digits displayed.
    * @param newValue A positive rounding increment, or 0.0 to
    * use the default rounding increment.
    * Negative increments are equivalent to 0.0.
    * @see #getRoundingIncrement
    * @see #getRoundingMode
    * @see #setRoundingMode
    * @stable ICU 2.0
    */
   virtual void setRoundingIncrement(double newValue);

   /**
    * Get the rounding mode.
    * @return A rounding mode
    * @see #setRoundingIncrement
    * @see #getRoundingIncrement
    * @see #setRoundingMode
    * @stable ICU 2.0
    */
   virtual ERoundingMode getRoundingMode() const override;

   /**
    * Set the rounding mode.
    * @param roundingMode A rounding mode
    * @see #setRoundingIncrement
    * @see #getRoundingIncrement
    * @see #getRoundingMode
    * @stable ICU 2.0
    */
   virtual void setRoundingMode(ERoundingMode roundingMode) override;

   /**
    * Get the width to which the output of format() is padded.
    * The width is counted in 16-bit code units.
    * @return the format width, or zero if no padding is in effect
    * @see #setFormatWidth
    * @see #getPadCharacterString
    * @see #setPadCharacter
    * @see #getPadPosition
    * @see #setPadPosition
    * @stable ICU 2.0
    */
   virtual int32_t getFormatWidth() const;

   /**
    * Set the width to which the output of format() is padded.
    * The width is counted in 16-bit code units.
    * This method also controls whether padding is enabled.
    * @param width the width to which to pad the result of
    * format(), or zero to disable padding.  A negative
    * width is equivalent to 0.
    * @see #getFormatWidth
    * @see #getPadCharacterString
    * @see #setPadCharacter
    * @see #getPadPosition
    * @see #setPadPosition
    * @stable ICU 2.0
    */
   virtual void setFormatWidth(int32_t width);

   /**
    * Get the pad character used to pad to the format width.  The
    * default is ' '.
    * @return a string containing the pad character. This will always
    * have a length of one 32-bit code point.
    * @see #setFormatWidth
    * @see #getFormatWidth
    * @see #setPadCharacter
    * @see #getPadPosition
    * @see #setPadPosition
    * @stable ICU 2.0
    */
   virtual UnicodeString getPadCharacterString() const;

   /**
    * Set the character used to pad to the format width.  If padding
    * is not enabled, then this will take effect if padding is later
    * enabled.
    * @param padChar a string containing the pad character. If the string
    * has length 0, then the pad character is set to ' '.  Otherwise
    * padChar.char32At(0) will be used as the pad character.
    * @see #setFormatWidth
    * @see #getFormatWidth
    * @see #getPadCharacterString
    * @see #getPadPosition
    * @see #setPadPosition
    * @stable ICU 2.0
    */
   virtual void setPadCharacter(const UnicodeString& padChar);

   /**
    * Get the position at which padding will take place.  This is the location
    * at which padding will be inserted if the result of format()
    * is shorter than the format width.
    * @return the pad position, one of kPadBeforePrefix,
    * kPadAfterPrefix, kPadBeforeSuffix, or
    * kPadAfterSuffix.
    * @see #setFormatWidth
    * @see #getFormatWidth
    * @see #setPadCharacter
    * @see #getPadCharacterString
    * @see #setPadPosition
    * @see #EPadPosition
    * @stable ICU 2.0
    */
   virtual EPadPosition getPadPosition() const;

   /**
    * Set the position at which padding will take place.  This is the location
    * at which padding will be inserted if the result of format()
    * is shorter than the format width.  This has no effect unless padding is
    * enabled.
    * @param padPos the pad position, one of kPadBeforePrefix,
    * kPadAfterPrefix, kPadBeforeSuffix, or
    * kPadAfterSuffix.
    * @see #setFormatWidth
    * @see #getFormatWidth
    * @see #setPadCharacter
    * @see #getPadCharacterString
    * @see #getPadPosition
    * @see #EPadPosition
    * @stable ICU 2.0
    */
   virtual void setPadPosition(EPadPosition padPos);

   /**
    * Return whether or not scientific notation is used.
    * @return true if this object formats and parses scientific notation
    * @see #setScientificNotation
    * @see #getMinimumExponentDigits
    * @see #setMinimumExponentDigits
    * @see #isExponentSignAlwaysShown
    * @see #setExponentSignAlwaysShown
    * @stable ICU 2.0
    */
   virtual UBool isScientificNotation() const;

   /**
    * Set whether or not scientific notation is used. When scientific notation
    * is used, the effective maximum number of integer digits is <= 8.  If the
    * maximum number of integer digits is set to more than 8, the effective
    * maximum will be 1.  This allows this call to generate a 'default' scientific
    * number format without additional changes.
    * @param useScientific true if this object formats and parses scientific
    * notation
    * @see #isScientificNotation
    * @see #getMinimumExponentDigits
    * @see #setMinimumExponentDigits
    * @see #isExponentSignAlwaysShown
    * @see #setExponentSignAlwaysShown
    * @stable ICU 2.0
    */
   virtual void setScientificNotation(UBool useScientific);

   /**
    * Return the minimum exponent digits that will be shown.
    * @return the minimum exponent digits that will be shown
    * @see #setScientificNotation
    * @see #isScientificNotation
    * @see #setMinimumExponentDigits
    * @see #isExponentSignAlwaysShown
    * @see #setExponentSignAlwaysShown
    * @stable ICU 2.0
    */
   virtual int8_t getMinimumExponentDigits() const;

   /**
    * Set the minimum exponent digits that will be shown.  This has no
    * effect unless scientific notation is in use.
    * @param minExpDig a value >= 1 indicating the fewest exponent digits
    * that will be shown.  Values less than 1 will be treated as 1.
    * @see #setScientificNotation
    * @see #isScientificNotation
    * @see #getMinimumExponentDigits
    * @see #isExponentSignAlwaysShown
    * @see #setExponentSignAlwaysShown
    * @stable ICU 2.0
    */
   virtual void setMinimumExponentDigits(int8_t minExpDig);

   /**
    * Return whether the exponent sign is always shown.
    * @return true if the exponent is always prefixed with either the
    * localized minus sign or the localized plus sign, false if only negative
    * exponents are prefixed with the localized minus sign.
    * @see #setScientificNotation
    * @see #isScientificNotation
    * @see #setMinimumExponentDigits
    * @see #getMinimumExponentDigits
    * @see #setExponentSignAlwaysShown
    * @stable ICU 2.0
    */
   virtual UBool isExponentSignAlwaysShown() const;

   /**
    * Set whether the exponent sign is always shown.  This has no effect
    * unless scientific notation is in use.
    * @param expSignAlways true if the exponent is always prefixed with either
    * the localized minus sign or the localized plus sign, false if only
    * negative exponents are prefixed with the localized minus sign.
    * @see #setScientificNotation
    * @see #isScientificNotation
    * @see #setMinimumExponentDigits
    * @see #getMinimumExponentDigits
    * @see #isExponentSignAlwaysShown
    * @stable ICU 2.0
    */
   virtual void setExponentSignAlwaysShown(UBool expSignAlways);

   /**
    * Return the grouping size. Grouping size is the number of digits between
    * grouping separators in the integer portion of a number.  For example,
    * in the number "123,456.78", the grouping size is 3.
    *
    * @return    the grouping size.
    * @see setGroupingSize
    * @see NumberFormat::isGroupingUsed
    * @see DecimalFormatSymbols::getGroupingSeparator
    * @stable ICU 2.0
    */
   int32_t getGroupingSize() const;

   /**
    * Set the grouping size. Grouping size is the number of digits between
    * grouping separators in the integer portion of a number.  For example,
    * in the number "123,456.78", the grouping size is 3.
    *
    * @param newValue    the new value of the grouping size.
    * @see getGroupingSize
    * @see NumberFormat::setGroupingUsed
    * @see DecimalFormatSymbols::setGroupingSeparator
    * @stable ICU 2.0
    */
   virtual void setGroupingSize(int32_t newValue);

   /**
    * Return the secondary grouping size. In some locales one
    * grouping interval is used for the least significant integer
    * digits (the primary grouping size), and another is used for all
    * others (the secondary grouping size).  A formatter supporting a
    * secondary grouping size will return a positive integer unequal
    * to the primary grouping size returned by
    * getGroupingSize().  For example, if the primary
    * grouping size is 4, and the secondary grouping size is 2, then
    * the number 123456789 formats as "1,23,45,6789", and the pattern
    * appears as "#,##,###0".
    * @return the secondary grouping size, or a value less than
    * one if there is none
    * @see setSecondaryGroupingSize
    * @see NumberFormat::isGroupingUsed
    * @see DecimalFormatSymbols::getGroupingSeparator
    * @stable ICU 2.4
    */
   int32_t getSecondaryGroupingSize() const;

   /**
    * Set the secondary grouping size. If set to a value less than 1,
    * then secondary grouping is turned off, and the primary grouping
    * size is used for all intervals, not just the least significant.
    *
    * @param newValue    the new value of the secondary grouping size.
    * @see getSecondaryGroupingSize
    * @see NumberFormat#setGroupingUsed
    * @see DecimalFormatSymbols::setGroupingSeparator
    * @stable ICU 2.4
    */
   virtual void setSecondaryGroupingSize(int32_t newValue);

   /**
    * Returns the minimum number of grouping digits.
    * Grouping separators are output if there are at least this many
    * digits to the left of the first (rightmost) grouping separator,
    * that is, there are at least (minimum grouping + grouping size) integer digits.
    * (Subject to isGroupingUsed().)
    *
    * For example, if this value is 2, and the grouping size is 3, then
    * 9999 -> "9999" and 10000 -> "10,000"
    *
    * The default value for this attribute is 0.
    * A value of 1, 0, or lower, means that the use of grouping separators
    * only depends on the grouping size (and on isGroupingUsed()).
    *
    * NOTE: The CLDR data is used in NumberFormatter but not in DecimalFormat.
    * This is for backwards compatibility reasons.
    *
    * For more control over grouping strategies, use NumberFormatter.
    *
    * @see setMinimumGroupingDigits
    * @see getGroupingSize
    * @stable ICU 64
    */
   int32_t getMinimumGroupingDigits() const;

   /**
    * Sets the minimum grouping digits. Setting the value to
    *  - 1: Turns off minimum grouping digits.
    *  - 0 or -1: The behavior is undefined.
    *  - UNUM_MINIMUM_GROUPING_DIGITS_AUTO: Display grouping using the default
    *      strategy for all locales.
    *  - UNUM_MINIMUM_GROUPING_DIGITS_MIN2: Display grouping using locale
    *      defaults, except do not show grouping on values smaller than 10000
    *      (such that there is a minimum of two digits before the first
    *      separator).
    *
    * For more control over grouping strategies, use NumberFormatter.
    *
    * @param newValue the new value of minimum grouping digits.
    * @see getMinimumGroupingDigits
    * @stable ICU 64
    */
   void setMinimumGroupingDigits(int32_t newValue);

   /**
    * Allows you to get the behavior of the decimal separator with integers.
    * (The decimal separator will always appear with decimals.)
    *
    * @return    true if the decimal separator always appear with decimals.
    * Example: Decimal ON: 12345 -> 12345.; OFF: 12345 -> 12345
    * @stable ICU 2.0
    */
   UBool isDecimalSeparatorAlwaysShown() const;

   /**
    * Allows you to set the behavior of the decimal separator with integers.
    * (The decimal separator will always appear with decimals.)
    *
    * @param newValue    set true if the decimal separator will always appear with decimals.
    * Example: Decimal ON: 12345 -> 12345.; OFF: 12345 -> 12345
    * @stable ICU 2.0
    */
   virtual void setDecimalSeparatorAlwaysShown(UBool newValue);

   /**
    * Allows you to get the parse behavior of the pattern decimal mark.
    *
    * @return    true if input must contain a match to decimal mark in pattern
    * @stable ICU 54
    */
   UBool isDecimalPatternMatchRequired() const;

   /**
    * Allows you to set the parse behavior of the pattern decimal mark.
    *
    * if true, the input must have a decimal mark if one was specified in the pattern. When
    * false the decimal mark may be omitted from the input.
    *
    * @param newValue    set true if input must contain a match to decimal mark in pattern
    * @stable ICU 54
    */
   virtual void setDecimalPatternMatchRequired(UBool newValue);

   /**
    * Returns whether to ignore exponents when parsing.
    *
    * @return Whether to ignore exponents when parsing.
    * @see #setParseNoExponent
    * @stable ICU 64
    */
   UBool isParseNoExponent() const;

   /**
    * Specifies whether to stop parsing when an exponent separator is encountered. For
    * example, parses "123E4" to 123 (with parse position 3) instead of 1230000 (with parse position
    * 5).
    *
    * @param value true to prevent exponents from being parsed; false to allow them to be parsed.
    * @stable ICU 64
    */
   void setParseNoExponent(UBool value);

   /**
    * Returns whether parsing is sensitive to case (lowercase/uppercase).
    *
    * @return Whether parsing is case-sensitive.
    * @see #setParseCaseSensitive
    * @stable ICU 64
    */
   UBool isParseCaseSensitive() const;

   /**
    * Whether to pay attention to case when parsing; default is to ignore case (perform
    * case-folding). For example, "A" == "a" in case-insensitive but not case-sensitive mode.
    *
    * Currency symbols are never case-folded. For example, "us$1.00" will not parse in case-insensitive
    * mode, even though "US$1.00" parses.
    *
    * @param value true to enable case-sensitive parsing (the default); false to force
    *              case-sensitive parsing behavior.
    * @stable ICU 64
    */
   void setParseCaseSensitive(UBool value);

   /**
    * Returns whether truncation of high-order integer digits should result in an error.
    * By default, setMaximumIntegerDigits truncates high-order digits silently.
    *
    * @return Whether an error code is set if high-order digits are truncated.
    * @see setFormatFailIfMoreThanMaxDigits
    * @stable ICU 64
    */
   UBool isFormatFailIfMoreThanMaxDigits() const;

   /**
    * Sets whether truncation of high-order integer digits should result in an error.
    * By default, setMaximumIntegerDigits truncates high-order digits silently.
    *
    * @param value Whether to set an error code if high-order digits are truncated.
    * @stable ICU 64
    */
   void setFormatFailIfMoreThanMaxDigits(UBool value);

   /**
    * Synthesizes a pattern string that represents the current state
    * of this Format object.
    *
    * @param result    Output param which will receive the pattern.
    *                  Previous contents are deleted.
    * @return          A reference to 'result'.
    * @see applyPattern
    * @stable ICU 2.0
    */
   virtual UnicodeString& toPattern(UnicodeString& result) const;

   /**
    * Synthesizes a localized pattern string that represents the current
    * state of this Format object.
    *
    * @param result    Output param which will receive the localized pattern.
    *                  Previous contents are deleted.
    * @return          A reference to 'result'.
    * @see applyPattern
    * @stable ICU 2.0
    */
   virtual UnicodeString& toLocalizedPattern(UnicodeString& result) const;

   /**
    * Apply the given pattern to this Format object.  A pattern is a
    * short-hand specification for the various formatting properties.
    * These properties can also be changed individually through the
    * various setter methods.
    * <P>
    * There is no limit to integer digits are set
    * by this routine, since that is the typical end-user desire;
    * use setMaximumInteger if you want to set a real value.
    * For negative numbers, use a second pattern, separated by a semicolon
    * <pre>
    * .      Example "#,#00.0#" -> 1,234.56
    * </pre>
    * This means a minimum of 2 integer digits, 1 fraction digit, and
    * a maximum of 2 fraction digits.
    * <pre>
    * .      Example: "#,#00.0#;(#,#00.0#)" for negatives in parentheses.
    * </pre>
    * In negative patterns, the minimum and maximum counts are ignored;
    * these are presumed to be set in the positive pattern.
    *
    * @param pattern    The pattern to be applied.
    * @param parseError Struct to receive information on position
    *                   of error if an error is encountered
    * @param status     Output param set to success/failure code on
    *                   exit. If the pattern is invalid, this will be
    *                   set to a failure result.
    * @stable ICU 2.0
    */
   virtual void applyPattern(const UnicodeString& pattern, UParseError& parseError, UErrorCode& status);

   /**
    * Sets the pattern.
    * @param pattern   The pattern to be applied.
    * @param status    Output param set to success/failure code on
    *                  exit. If the pattern is invalid, this will be
    *                  set to a failure result.
    * @stable ICU 2.0
    */
   virtual void applyPattern(const UnicodeString& pattern, UErrorCode& status);

   /**
    * Apply the given pattern to this Format object.  The pattern
    * is assumed to be in a localized notation. A pattern is a
    * short-hand specification for the various formatting properties.
    * These properties can also be changed individually through the
    * various setter methods.
    * <P>
    * There is no limit to integer digits are set
    * by this routine, since that is the typical end-user desire;
    * use setMaximumInteger if you want to set a real value.
    * For negative numbers, use a second pattern, separated by a semicolon
    * <pre>
    * .      Example "#,#00.0#" -> 1,234.56
    * </pre>
    * This means a minimum of 2 integer digits, 1 fraction digit, and
    * a maximum of 2 fraction digits.
    *
    * Example: "#,#00.0#;(#,#00.0#)" for negatives in parentheses.
    *
    * In negative patterns, the minimum and maximum counts are ignored;
    * these are presumed to be set in the positive pattern.
    *
    * @param pattern   The localized pattern to be applied.
    * @param parseError Struct to receive information on position
    *                   of error if an error is encountered
    * @param status    Output param set to success/failure code on
    *                  exit. If the pattern is invalid, this will be
    *                  set to a failure result.
    * @stable ICU 2.0
    */
   virtual void applyLocalizedPattern(const UnicodeString& pattern, UParseError& parseError,
                                      UErrorCode& status);

   /**
    * Apply the given pattern to this Format object.
    *
    * @param pattern   The localized pattern to be applied.
    * @param status    Output param set to success/failure code on
    *                  exit. If the pattern is invalid, this will be
    *                  set to a failure result.
    * @stable ICU 2.0
    */
   virtual void applyLocalizedPattern(const UnicodeString& pattern, UErrorCode& status);


   /**
    * Sets the maximum number of digits allowed in the integer portion of a
    * number. This override limits the integer digit count to 309.
    *
    * @param newValue    the new value of the maximum number of digits
    *                      allowed in the integer portion of a number.
    * @see NumberFormat#setMaximumIntegerDigits
    * @stable ICU 2.0
    */
   void setMaximumIntegerDigits(int32_t newValue) override;

   /**
    * Sets the minimum number of digits allowed in the integer portion of a
    * number. This override limits the integer digit count to 309.
    *
    * @param newValue    the new value of the minimum number of digits
    *                      allowed in the integer portion of a number.
    * @see NumberFormat#setMinimumIntegerDigits
    * @stable ICU 2.0
    */
   void setMinimumIntegerDigits(int32_t newValue) override;

   /**
    * Sets the maximum number of digits allowed in the fraction portion of a
    * number. This override limits the fraction digit count to 340.
    *
    * @param newValue    the new value of the maximum number of digits
    *                    allowed in the fraction portion of a number.
    * @see NumberFormat#setMaximumFractionDigits
    * @stable ICU 2.0
    */
   void setMaximumFractionDigits(int32_t newValue) override;

   /**
    * Sets the minimum number of digits allowed in the fraction portion of a
    * number. This override limits the fraction digit count to 340.
    *
    * @param newValue    the new value of the minimum number of digits
    *                    allowed in the fraction portion of a number.
    * @see NumberFormat#setMinimumFractionDigits
    * @stable ICU 2.0
    */
   void setMinimumFractionDigits(int32_t newValue) override;

   /**
    * Returns the minimum number of significant digits that will be
    * displayed. This value has no effect unless areSignificantDigitsUsed()
    * returns true.
    * @return the fewest significant digits that will be shown
    * @stable ICU 3.0
    */
   int32_t getMinimumSignificantDigits() const;

   /**
    * Returns the maximum number of significant digits that will be
    * displayed. This value has no effect unless areSignificantDigitsUsed()
    * returns true.
    * @return the most significant digits that will be shown
    * @stable ICU 3.0
    */
   int32_t getMaximumSignificantDigits() const;

   /**
    * Sets the minimum number of significant digits that will be
    * displayed.  If <code>min</code> is less than one then it is set
    * to one.  If the maximum significant digits count is less than
    * <code>min</code>, then it is set to <code>min</code>.
    * This function also enables the use of significant digits
    * by this formatter - areSignificantDigitsUsed() will return true.
    * @see #areSignificantDigitsUsed
    * @param min the fewest significant digits to be shown
    * @stable ICU 3.0
    */
   void setMinimumSignificantDigits(int32_t min);

   /**
    * Sets the maximum number of significant digits that will be
    * displayed.  If <code>max</code> is less than one then it is set
    * to one.  If the minimum significant digits count is greater
    * than <code>max</code>, then it is set to <code>max</code>.
    * This function also enables the use of significant digits
    * by this formatter - areSignificantDigitsUsed() will return true.
    * @see #areSignificantDigitsUsed
    * @param max the most significant digits to be shown
    * @stable ICU 3.0
    */
   void setMaximumSignificantDigits(int32_t max);

   /**
    * Returns true if significant digits are in use, or false if
    * integer and fraction digit counts are in use.
    * @return true if significant digits are in use
    * @stable ICU 3.0
    */
   UBool areSignificantDigitsUsed() const;

   /**
    * Sets whether significant digits are in use, or integer and
    * fraction digit counts are in use.
    * @param useSignificantDigits true to use significant digits, or
    * false to use integer and fraction digit counts
    * @stable ICU 3.0
    */
   void setSignificantDigitsUsed(UBool useSignificantDigits);

   /**
    * Sets the currency used to display currency
    * amounts.  This takes effect immediately, if this format is a
    * currency format.  If this format is not a currency format, then
    * the currency is used if and when this object becomes a
    * currency format through the application of a new pattern.
    * @param theCurrency a 3-letter ISO code indicating new currency
    * to use.  It need not be null-terminated.  May be the empty
    * string or nullptr to indicate no currency.
    * @param ec input-output error code
    * @stable ICU 3.0
    */
   void setCurrency(const char16_t* theCurrency, UErrorCode& ec) override;

#ifndef U_FORCE_HIDE_DEPRECATED_API
   /**
    * Sets the currency used to display currency amounts.  See
    * setCurrency(const char16_t*, UErrorCode&).
    * @deprecated ICU 3.0. Use setCurrency(const char16_t*, UErrorCode&).
    */
   virtual void setCurrency(const char16_t* theCurrency);
#endif  // U_FORCE_HIDE_DEPRECATED_API

   /**
    * Sets the `Currency Usage` object used to display currency.
    * This takes effect immediately, if this format is a
    * currency format.
    * @param newUsage new currency usage object to use.
    * @param ec input-output error code
    * @stable ICU 54
    */
   void setCurrencyUsage(UCurrencyUsage newUsage, UErrorCode* ec);

   /**
    * Returns the `Currency Usage` object used to display currency
    * @stable ICU 54
    */
   UCurrencyUsage getCurrencyUsage() const;

#ifndef U_HIDE_INTERNAL_API

   /**
    *  Format a number and save it into the given DecimalQuantity.
    *  Internal, not intended for public use.
    *  @internal
    */
   void formatToDecimalQuantity(double number, number::impl::DecimalQuantity& output,
                                UErrorCode& status) const;

   /**
    *  Get a DecimalQuantity corresponding to a formattable as it would be
    *  formatted by this DecimalFormat.
    *  Internal, not intended for public use.
    *  @internal
    */
   void formatToDecimalQuantity(const Formattable& number, number::impl::DecimalQuantity& output,
                                UErrorCode& status) const;

#endif  /* U_HIDE_INTERNAL_API */

   /**
    * Converts this DecimalFormat to a (Localized)NumberFormatter. Starting
    * in ICU 60, NumberFormatter is the recommended way to format numbers.
    * You can use the returned LocalizedNumberFormatter to format numbers and
    * get a FormattedNumber, which contains a string as well as additional
    * annotations about the formatted value.
    * 
    * If a memory allocation failure occurs, the return value of this method
    * might be null. If you are concerned about correct recovery from
    * out-of-memory situations, use this pattern:
    *
    * <pre>
    * FormattedNumber result;
    * if (auto* ptr = df->toNumberFormatter(status)) {
    *     result = ptr->formatDouble(123, status);
    * }
    * </pre>
    *
    * If you are not concerned about out-of-memory situations, or if your
    * environment throws exceptions when memory allocation failure occurs,
    * you can chain the methods, like this:
    *
    * <pre>
    * FormattedNumber result = df
    *     ->toNumberFormatter(status)
    *     ->formatDouble(123, status);
    * </pre>
    *
    * NOTE: The returned LocalizedNumberFormatter is owned by this DecimalFormat.
    * If a non-const method is called on the DecimalFormat, or if the DecimalFormat
    * is deleted, the object becomes invalid. If you plan to keep the return value
    * beyond the lifetime of the DecimalFormat, copy it to a local variable:
    *
    * <pre>
    * LocalizedNumberFormatter lnf;
    * if (auto* ptr = df->toNumberFormatter(status)) {
    *     lnf = *ptr;
    * }
    * </pre>
    *
    * @param status Set on failure, like U_MEMORY_ALLOCATION_ERROR.
    * @return A pointer to an internal object, or nullptr on failure.
    *         Do not delete the return value!
    * @stable ICU 64
    */
   const number::LocalizedNumberFormatter* toNumberFormatter(UErrorCode& status) const;

   /**
    * Return the class ID for this class.  This is useful only for
    * comparing to a return value from getDynamicClassID().  For example:
    * <pre>
    * .      Base* polymorphic_pointer = createPolymorphicObject();
    * .      if (polymorphic_pointer->getDynamicClassID() ==
    * .          Derived::getStaticClassID()) ...
    * </pre>
    * @return          The class ID for all objects of this class.
    * @stable ICU 2.0
    */
   static UClassID U_EXPORT2 getStaticClassID();

   /**
    * Returns a unique class ID POLYMORPHICALLY.  Pure virtual override.
    * This method is to implement a simple version of RTTI, since not all
    * C++ compilers support genuine RTTI.  Polymorphic operator==() and
    * clone() methods call this method.
    *
    * @return          The class ID for this object. All objects of a
    *                  given class have the same class ID.  Objects of
    *                  other classes have different class IDs.
    * @stable ICU 2.0
    */
   UClassID getDynamicClassID() const override;

 private:

   /** Rebuilds the formatter object from the property bag. */
   void touch(UErrorCode& status);

   /** Rebuilds the formatter object, ignoring any error code. */
   void touchNoError();

   /**
    * Updates the property bag with settings from the given pattern.
    *
    * @param pattern The pattern string to parse.
    * @param ignoreRounding Whether to leave out rounding information (minFrac, maxFrac, and rounding
    *     increment) when parsing the pattern. This may be desirable if a custom rounding mode, such
    *     as CurrencyUsage, is to be used instead. One of {@link
    *     PatternStringParser#IGNORE_ROUNDING_ALWAYS}, {@link PatternStringParser#IGNORE_ROUNDING_IF_CURRENCY},
    *     or {@link PatternStringParser#IGNORE_ROUNDING_NEVER}.
    * @see PatternAndPropertyUtils#parseToExistingProperties
    */
   void setPropertiesFromPattern(const UnicodeString& pattern, int32_t ignoreRounding,
                                 UErrorCode& status);

   const numparse::impl::NumberParserImpl* getParser(UErrorCode& status) const;

   const numparse::impl::NumberParserImpl* getCurrencyParser(UErrorCode& status) const;

   static void fieldPositionHelper(
       const number::impl::UFormattedNumberData& formatted,
       FieldPosition& fieldPosition,
       int32_t offset,
       UErrorCode& status);

   static void fieldPositionIteratorHelper(
       const number::impl::UFormattedNumberData& formatted,
       FieldPositionIterator* fpi,
       int32_t offset,
       UErrorCode& status);

   void setupFastFormat();

   bool fastFormatDouble(double input, UnicodeString& output) const;

   bool fastFormatInt64(int64_t input, UnicodeString& output) const;

   void doFastFormatInt32(int32_t input, bool isNegative, UnicodeString& output) const;

   //=====================================================================================//
   //                                   INSTANCE FIELDS                                   //
   //=====================================================================================//


   // One instance field for the implementation, keep all fields inside of an implementation
   // class defined in number_mapper.h
   number::impl::DecimalFormatFields* fields = nullptr;

   // Allow child class CompactDecimalFormat to access fProperties:
   friend class CompactDecimalFormat;

   // Allow MeasureFormat to use fieldPositionHelper:
   friend class MeasureFormat;

};

U_NAMESPACE_END

#endif /* #if !UCONFIG_NO_FORMATTING */

#endif /* U_SHOW_CPLUSPLUS_API */

#endif // _DECIMFMT
//eof