chromium/third_party/icu/source/i18n/number_roundingutils.h

// © 2017 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html

#include "unicode/utypes.h"

#if !UCONFIG_NO_FORMATTING
#ifndef __NUMBER_ROUNDINGUTILS_H__
#define __NUMBER_ROUNDINGUTILS_H__

#include "number_types.h"
#include "string_segment.h"

U_NAMESPACE_BEGIN
namespace number {
namespace impl {
namespace roundingutils {

enum Section { … };

/**
 * Converts a rounding mode and metadata about the quantity being rounded to a boolean determining
 * whether the value should be rounded toward infinity or toward zero.
 *
 * <p>The parameters are of type int because benchmarks on an x86-64 processor against OpenJDK
 * showed that ints were demonstrably faster than enums in switch statements.
 *
 * @param isEven Whether the digit immediately before the rounding magnitude is even.
 * @param isNegative Whether the quantity is negative.
 * @param section Whether the part of the quantity to the right of the rounding magnitude is
 *     exactly halfway between two digits, whether it is in the lower part (closer to zero), or
 *     whether it is in the upper part (closer to infinity). See {@link #SECTION_LOWER}, {@link
 *     #SECTION_MIDPOINT}, and {@link #SECTION_UPPER}.
 * @param roundingMode The integer version of the {@link RoundingMode}, which you can get via
 *     {@link RoundingMode#ordinal}.
 * @param status Error code, set to U_FORMAT_INEXACT_ERROR if the rounding mode is kRoundUnnecessary.
 * @return true if the number should be rounded toward zero; false if it should be rounded toward
 *     infinity.
 */
inline bool
getRoundingDirection(bool isEven, bool isNegative, Section section, RoundingMode roundingMode,
                     UErrorCode &status) { … }

/**
 * Gets whether the given rounding mode's rounding boundary is at the midpoint. The rounding
 * boundary is the point at which a number switches from being rounded down to being rounded up.
 * For example, with rounding mode HALF_EVEN, HALF_UP, or HALF_DOWN, the rounding boundary is at
 * the midpoint, and this function would return true. However, for UP, DOWN, CEILING, and FLOOR,
 * the rounding boundary is at the "edge", and this function would return false.
 *
 * @param roundingMode The integer version of the {@link RoundingMode}.
 * @return true if rounding mode is HALF_EVEN, HALF_UP, or HALF_DOWN; false otherwise.
 */
inline bool roundsAtMidpoint(int roundingMode) { … }

} // namespace roundingutils


/**
 * Encapsulates a Precision and a RoundingMode and performs rounding on a DecimalQuantity.
 *
 * This class does not exist in Java: instead, the base Precision class is used.
 */
class RoundingImpl { … };

/**
 * Parses Precision-related skeleton strings without knowledge of MacroProps
 * - see blueprint_helpers::parseIncrementOption().
 *
 * Referencing MacroProps means needing to pull in the .o files that have the
 * destructors for the SymbolsWrapper, StringProp, and Scale classes.
 */
void parseIncrementOption(const StringSegment &segment, Precision &outPrecision, UErrorCode &status);

} // namespace impl
} // namespace number
U_NAMESPACE_END

#endif //__NUMBER_ROUNDINGUTILS_H__

#endif /* #if !UCONFIG_NO_FORMATTING */