chromium/third_party/icu/source/i18n/unicode/unumberformatter.h

// © 2018 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html

#ifndef __UNUMBERFORMATTER_H__
#define __UNUMBERFORMATTER_H__

#include "unicode/utypes.h"

#if !UCONFIG_NO_FORMATTING

#include "unicode/parseerr.h"
#include "unicode/unumberoptions.h"
#include "unicode/uformattednumber.h"


/**
 * \file
 * \brief C API: Localized number formatting; not recommended for C++.
 *
 * This is the C-compatible version of the NumberFormatter API introduced in ICU 60. C++ users should
 * include unicode/numberformatter.h and use the proper C++ APIs.
 *
 * The C API accepts a number skeleton string for specifying the settings for formatting, which covers a
 * very large subset of all possible number formatting features. For more information on number skeleton
 * strings, see unicode/numberformatter.h.
 *
 * When using UNumberFormatter, which is treated as immutable, the results are exported to a mutable
 * UFormattedNumber object, which you subsequently use for populating your string buffer or iterating over
 * the fields.
 *
 * Example code:
 * <pre>
 * // Setup:
 * UErrorCode ec = U_ZERO_ERROR;
 * UNumberFormatter* uformatter = unumf_openForSkeletonAndLocale(u"precision-integer", -1, "en", &ec);
 * UFormattedNumber* uresult = unumf_openResult(&ec);
 * if (U_FAILURE(ec)) { return; }
 *
 * // Format a double:
 * unumf_formatDouble(uformatter, 5142.3, uresult, &ec);
 * if (U_FAILURE(ec)) { return; }
 *
 * // Export the string to a malloc'd buffer:
 * int32_t len = unumf_resultToString(uresult, NULL, 0, &ec);
 * // at this point, ec == U_BUFFER_OVERFLOW_ERROR
 * ec = U_ZERO_ERROR;
 * UChar* buffer = (UChar*) malloc((len+1)*sizeof(UChar));
 * unumf_resultToString(uresult, buffer, len+1, &ec);
 * if (U_FAILURE(ec)) { return; }
 * // buffer should equal "5,142"
 *
 * // Cleanup:
 * unumf_close(uformatter);
 * unumf_closeResult(uresult);
 * free(buffer);
 * </pre>
 *
 * If you are a C++ user linking against the C libraries, you can use the LocalPointer versions of these
 * APIs. The following example uses LocalPointer with the decimal number and field position APIs:
 *
 * <pre>
 * // Setup:
 * LocalUNumberFormatterPointer uformatter(unumf_openForSkeletonAndLocale(u"percent", -1, "en", &ec));
 * LocalUFormattedNumberPointer uresult(unumf_openResult(&ec));
 * if (U_FAILURE(ec)) { return; }
 *
 * // Format a decimal number:
 * unumf_formatDecimal(uformatter.getAlias(), "9.87E-3", -1, uresult.getAlias(), &ec);
 * if (U_FAILURE(ec)) { return; }
 *
 * // Get the location of the percent sign:
 * UFieldPosition ufpos = {UNUM_PERCENT_FIELD, 0, 0};
 * unumf_resultNextFieldPosition(uresult.getAlias(), &ufpos, &ec);
 * // ufpos should contain beginIndex=7 and endIndex=8 since the string is "0.00987%"
 *
 * // No need to do any cleanup since we are using LocalPointer.
 * </pre>
 */

/**
 * An enum declaring how to resolve conflicts between maximum fraction digits and maximum
 * significant digits.
 *
 * There are two modes, RELAXED and STRICT:
 *
 * - RELAXED: Relax one of the two constraints (fraction digits or significant digits) in order
 *   to round the number to a higher level of precision.
 * - STRICT: Enforce both constraints, resulting in the number being rounded to a lower
 *   level of precision.
 *
 * The default settings for compact notation rounding are Max-Fraction = 0 (round to the nearest
 * integer), Max-Significant = 2 (round to 2 significant digits), and priority RELAXED (choose
 * the constraint that results in more digits being displayed).
 *
 * Conflicting *minimum* fraction and significant digits are always resolved in the direction that
 * results in more trailing zeros.
 *
 * Example 1: Consider the number 3.141, with various different settings:
 *
 * - Max-Fraction = 1: "3.1"
 * - Max-Significant = 3: "3.14"
 *
 * The rounding priority determines how to resolve the conflict when both Max-Fraction and
 * Max-Significant are set. With RELAXED, the less-strict setting (the one that causes more digits
 * to be displayed) will be used; Max-Significant wins. With STRICT, the more-strict setting (the
 * one that causes fewer digits to be displayed) will be used; Max-Fraction wins.
 *
 * Example 2: Consider the number 8317, with various different settings:
 *
 * - Max-Fraction = 1: "8317"
 * - Max-Significant = 3: "8320"
 *
 * Here, RELAXED favors Max-Fraction and STRICT favors Max-Significant. Note that this larger
 * number caused the two modes to favor the opposite result.
 *
 * @stable ICU 69
 */
UNumberRoundingPriority;

/**
 * An enum declaring how to render units, including currencies. Example outputs when formatting 123 USD and 123
 * meters in <em>en-CA</em>:
 *
 * <p>
 * <ul>
 * <li>NARROW*: "$123.00" and "123 m"
 * <li>SHORT: "US$ 123.00" and "123 m"
 * <li>FULL_NAME: "123.00 US dollars" and "123 meters"
 * <li>ISO_CODE: "USD 123.00" and undefined behavior
 * <li>HIDDEN: "123.00" and "123"
 * </ul>
 *
 * <p>
 * This enum is similar to {@link UMeasureFormatWidth}.
 *
 * @stable ICU 60
 */
UNumberUnitWidth;

/**
 * An enum declaring how to denote positive and negative numbers. Example outputs when formatting
 * 123, 0, and -123 in <em>en-US</em>:
 *
 * <ul>
 * <li>AUTO: "123", "0", and "-123"
 * <li>ALWAYS: "+123", "+0", and "-123"
 * <li>NEVER: "123", "0", and "123"
 * <li>ACCOUNTING: "$123", "$0", and "($123)"
 * <li>ACCOUNTING_ALWAYS: "+$123", "+$0", and "($123)"
 * <li>EXCEPT_ZERO: "+123", "0", and "-123"
 * <li>ACCOUNTING_EXCEPT_ZERO: "+$123", "$0", and "($123)"
 * </ul>
 *
 * <p>
 * The exact format, including the position and the code point of the sign, differ by locale.
 *
 * @stable ICU 60
 */
UNumberSignDisplay;

/**
 * An enum declaring how to render the decimal separator.
 *
 * <p>
 * <ul>
 * <li>UNUM_DECIMAL_SEPARATOR_AUTO: "1", "1.1"
 * <li>UNUM_DECIMAL_SEPARATOR_ALWAYS: "1.", "1.1"
 * </ul>
 *
 * @stable ICU 60
 */
UNumberDecimalSeparatorDisplay;

/**
 * An enum declaring how to render trailing zeros.
 * 
 * - UNUM_TRAILING_ZERO_AUTO: 0.90, 1.00, 1.10
 * - UNUM_TRAILING_ZERO_HIDE_IF_WHOLE: 0.90, 1, 1.10
 * 
 * @stable ICU 69
 */
UNumberTrailingZeroDisplay;

struct UNumberFormatter;
/**
 * C-compatible version of icu::number::LocalizedNumberFormatter.
 *
 * NOTE: This is a C-compatible API; C++ users should build against numberformatter.h instead.
 *
 * @stable ICU 62
 */
UNumberFormatter;


/**
 * Creates a new UNumberFormatter for the given skeleton string and locale. This is currently the only
 * method for creating a new UNumberFormatter.
 *
 * Objects of type UNumberFormatter returned by this method are threadsafe.
 *
 * For more details on skeleton strings, see the documentation in numberformatter.h. For more details on
 * the usage of this API, see the documentation at the top of unumberformatter.h.
 *
 * For more information on number skeleton strings, see:
 * https://unicode-org.github.io/icu/userguide/format_parse/numbers/skeletons.html
 *
 * NOTE: This is a C-compatible API; C++ users should build against numberformatter.h instead.
 *
 * @param skeleton The skeleton string, like u"percent precision-integer"
 * @param skeletonLen The number of UChars in the skeleton string, or -1 if it is NUL-terminated.
 * @param locale The NUL-terminated locale ID.
 * @param ec Set if an error occurs.
 * @stable ICU 62
 */
U_CAPI UNumberFormatter* U_EXPORT2
unumf_openForSkeletonAndLocale(const UChar* skeleton, int32_t skeletonLen, const char* locale,
                               UErrorCode* ec);


/**
 * Like unumf_openForSkeletonAndLocale, but accepts a UParseError, which will be populated with the
 * location of a skeleton syntax error if such a syntax error exists.
 *
 * For more information on number skeleton strings, see:
 * https://unicode-org.github.io/icu/userguide/format_parse/numbers/skeletons.html
 *
 * @param skeleton The skeleton string, like u"percent precision-integer"
 * @param skeletonLen The number of UChars in the skeleton string, or -1 if it is NUL-terminated.
 * @param locale The NUL-terminated locale ID.
 * @param perror A parse error struct populated if an error occurs when parsing. Can be NULL.
 *               If no error occurs, perror->offset will be set to -1.
 * @param ec Set if an error occurs.
 * @stable ICU 64
 */
U_CAPI UNumberFormatter* U_EXPORT2
unumf_openForSkeletonAndLocaleWithError(
       const UChar* skeleton, int32_t skeletonLen, const char* locale, UParseError* perror, UErrorCode* ec);



/**
 * Uses a UNumberFormatter to format an integer to a UFormattedNumber. A string, field position, and other
 * information can be retrieved from the UFormattedNumber.
 *
 * The UNumberFormatter can be shared between threads. Each thread should have its own local
 * UFormattedNumber, however, for storing the result of the formatting operation.
 *
 * NOTE: This is a C-compatible API; C++ users should build against numberformatter.h instead.
 *
 * @param uformatter A formatter object created by unumf_openForSkeletonAndLocale or similar.
 * @param value The number to be formatted.
 * @param uresult The object that will be mutated to store the result; see unumf_openResult.
 * @param ec Set if an error occurs.
 * @stable ICU 62
 */
U_CAPI void U_EXPORT2
unumf_formatInt(const UNumberFormatter* uformatter, int64_t value, UFormattedNumber* uresult,
                UErrorCode* ec);


/**
 * Uses a UNumberFormatter to format a double to a UFormattedNumber. A string, field position, and other
 * information can be retrieved from the UFormattedNumber.
 *
 * The UNumberFormatter can be shared between threads. Each thread should have its own local
 * UFormattedNumber, however, for storing the result of the formatting operation.
 *
 * NOTE: This is a C-compatible API; C++ users should build against numberformatter.h instead.
 *
 * @param uformatter A formatter object created by unumf_openForSkeletonAndLocale or similar.
 * @param value The number to be formatted.
 * @param uresult The object that will be mutated to store the result; see unumf_openResult.
 * @param ec Set if an error occurs.
 * @stable ICU 62
 */
U_CAPI void U_EXPORT2
unumf_formatDouble(const UNumberFormatter* uformatter, double value, UFormattedNumber* uresult,
                   UErrorCode* ec);


/**
 * Uses a UNumberFormatter to format a decimal number to a UFormattedNumber. A string, field position, and
 * other information can be retrieved from the UFormattedNumber.
 *
 * The UNumberFormatter can be shared between threads. Each thread should have its own local
 * UFormattedNumber, however, for storing the result of the formatting operation.
 *
 * The syntax of the unformatted number is a "numeric string" as defined in the Decimal Arithmetic
 * Specification, available at http://speleotrove.com/decimal
 *
 * NOTE: This is a C-compatible API; C++ users should build against numberformatter.h instead.
 *
 * @param uformatter A formatter object created by unumf_openForSkeletonAndLocale or similar.
 * @param value The numeric string to be formatted.
 * @param valueLen The length of the numeric string, or -1 if it is NUL-terminated.
 * @param uresult The object that will be mutated to store the result; see unumf_openResult.
 * @param ec Set if an error occurs.
 * @stable ICU 62
 */
U_CAPI void U_EXPORT2
unumf_formatDecimal(const UNumberFormatter* uformatter, const char* value, int32_t valueLen,
                    UFormattedNumber* uresult, UErrorCode* ec);



/**
 * Releases the UNumberFormatter created by unumf_openForSkeletonAndLocale().
 *
 * @param uformatter An object created by unumf_openForSkeletonAndLocale().
 * @stable ICU 62
 */
U_CAPI void U_EXPORT2
unumf_close(UNumberFormatter* uformatter);



#if U_SHOW_CPLUSPLUS_API
U_NAMESPACE_BEGIN

/**
 * \class LocalUNumberFormatterPointer
 * "Smart pointer" class; closes a UNumberFormatter via unumf_close().
 * For most methods see the LocalPointerBase base class.
 *
 * Usage:
 * <pre>
 * LocalUNumberFormatterPointer uformatter(unumf_openForSkeletonAndLocale(...));
 * // no need to explicitly call unumf_close()
 * </pre>
 *
 * @see LocalPointerBase
 * @see LocalPointer
 * @stable ICU 62
 */
U_DEFINE_LOCAL_OPEN_POINTER(…);

U_NAMESPACE_END
#endif // U_SHOW_CPLUSPLUS_API

#endif /* #if !UCONFIG_NO_FORMATTING */
#endif //__UNUMBERFORMATTER_H__