org.decimal4j.arithmetic

Class Rounding

java.lang.Object

org.decimal4j.arithmetic.Rounding

final class Rounding
extends Object

Utility class to calculate rounding increments in different situations; utilizes functionality provided by DecimalRounding and TruncatedPart.

Method Summary

Modifier and Type	Method and Description
static int	calculateRoundingIncrement(DecimalRounding rounding, int sign, long truncatedValue, int firstTruncatedDigit, boolean zeroAfterFirstTruncatedDigit) Returns the rounding increment appropriate for the specified rounding.
static int	calculateRoundingIncrement(DecimalRounding rounding, long truncatedValue, long truncatedDigits, long one) Returns the rounding increment appropriate for the specified rounding given the remaining truncated digits truncated by modulo one.
static int	calculateRoundingIncrementForDivision(DecimalRounding rounding, long truncatedValue, long truncatedDigits, long divisor) Returns the rounding increment appropriate for the specified rounding given the remaining truncated digits truncated by a given divisor.
static TruncatedPart	truncatedPartFor(long nonNegativeRemainder, long nonNegativeDivisor) Returns a truncated part constant given a non-negative remainder resulting from a division by the given non-negative divisor.
static TruncatedPart	truncatedPartFor2pow63(long remainder) Returns a truncated part constant given a non-negative remainder resulting from a division by 2^63
static TruncatedPart	truncatedPartFor2pow64(long remainder) Returns a truncated part constant given a non-negative remainder resulting from a division by 2^64
static TruncatedPart	truncatedPartFor2powN(long remainder, int n) Returns a truncated part constant given a non-negative remainder resulting from a division by 2^n
static TruncatedPart	truncatedPartFor2powN(long hRemainder, long lRemainder, int n) Returns a truncated part constant given a non-negative 128 bit remainder resulting from a division by 2^n
static TruncatedPart	truncatedPartForScale19(long remainder) Returns a truncated part constant given a non-negative remainder resulting from a division by 10^19.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

calculateRoundingIncrement

public static final int calculateRoundingIncrement(DecimalRounding rounding,
                                                   int sign,
                                                   long truncatedValue,
                                                   int firstTruncatedDigit,
                                                   boolean zeroAfterFirstTruncatedDigit)

Returns the rounding increment appropriate for the specified rounding. The returned value is one of -1, 0 or 1.

Parameters:

rounding - the rounding mode to apply

sign - the sign of the total value, either +1 or -1; determines the result value if rounded

truncatedValue - the truncated result before rounding is applied (only used for HALF_EVEN rounding)

firstTruncatedDigit - the first truncated digit, must be in [0, 1, ..., 9]

zeroAfterFirstTruncatedDigit - true if all truncated digits after the first truncated digit are zero, and false otherwise

Returns:

the value to add to truncatedValue to get the rounded result, one of -1, 0 or 1

calculateRoundingIncrementForDivision

public static final int calculateRoundingIncrementForDivision(DecimalRounding rounding,
                                                              long truncatedValue,
                                                              long truncatedDigits,
                                                              long divisor)

Returns the rounding increment appropriate for the specified rounding given the remaining truncated digits truncated by a given divisor. The returned value is one of -1, 0 or 1.

Parameters:

rounding - the rounding mode to apply

truncatedValue - the truncated result before rounding is applied (only used for HALF_EVEN rounding)

truncatedDigits - the truncated part, it most hold that abs(truncatedDigits) < abs(divisor)

divisor - the divisor that led to the truncated digits

Returns:

the value to add to truncatedValue to get the rounded result, one of -1, 0 or 1

calculateRoundingIncrement

public static final int calculateRoundingIncrement(DecimalRounding rounding,
                                                   long truncatedValue,
                                                   long truncatedDigits,
                                                   long one)

Returns the rounding increment appropriate for the specified rounding given the remaining truncated digits truncated by modulo one. The returned value is one of -1, 0 or 1.

Parameters:

rounding - the rounding mode to apply

truncatedValue - the truncated result before rounding is applied (only used for HALF_EVEN rounding)

truncatedDigits - the truncated part of a double, must be >-one and <one

one - the value representing 1 which is 10^scale, must be >= 10

Returns:

the value to add to truncatedValue to get the rounded result, one of -1, 0 or 1

truncatedPartFor

public static final TruncatedPart truncatedPartFor(long nonNegativeRemainder,
                                                   long nonNegativeDivisor)

Returns a truncated part constant given a non-negative remainder resulting from a division by the given non-negative divisor.

Parameters:

nonNegativeRemainder - the remainder part, not negative and nonNegativeRemainder < nonNegativeDivisor

nonNegativeDivisor - the divisor, not negative or LONG.MIN_VALUE --- the latter equal to abs(Long.MIN_VALUE)

Returns:

the truncated part constant equivalent to the given arguments

truncatedPartForScale19

public static final TruncatedPart truncatedPartForScale19(long remainder)

Returns a truncated part constant given a non-negative remainder resulting from a division by 10^19.

Parameters:

remainder - the remainder part

Returns:

the truncated part constant equivalent to the given arguments

truncatedPartFor2powN

public static final TruncatedPart truncatedPartFor2powN(long remainder,
                                                        int n)

Returns a truncated part constant given a non-negative remainder resulting from a division by 2^n

Parameters:

remainder - the remainder part

n - the power of 2 of the divisor, n > 0

Returns:

the truncated part constant equivalent to the given arguments

truncatedPartFor2powN

public static final TruncatedPart truncatedPartFor2powN(long hRemainder,
                                                        long lRemainder,
                                                        int n)

Returns a truncated part constant given a non-negative 128 bit remainder resulting from a division by 2^n

Parameters:

hRemainder - the high bits of the remainder part

lRemainder - the low bits of the remainder part

n - the power of 2 of the divisor, n > 0

Returns:

the truncated part constant equivalent to the given arguments

truncatedPartFor2pow63

public static final TruncatedPart truncatedPartFor2pow63(long remainder)

Returns a truncated part constant given a non-negative remainder resulting from a division by 2^63

Parameters:

remainder - the remainder part

Returns:

the truncated part constant equivalent to the given arguments

truncatedPartFor2pow64

public static final TruncatedPart truncatedPartFor2pow64(long remainder)

Returns a truncated part constant given a non-negative remainder resulting from a division by 2^64

Parameters:

remainder - the remainder part

Returns:

the truncated part constant equivalent to the given arguments