Apache POI - Common 5.3.0 · org.apache.poi.ss.util.NormalisedDecimal

Represents a transformation of a 64 bit IEEE double quantity having a decimal exponent and a fixed point (15 decimal digit) significand. Some quirks of Excel's calculation behaviour are simpler to reproduce with numeric quantities in this format. This class is currently used to help:

Comparison operations
Conversions to text

This class does not handle negative numbers or zero.

The value of a NormalisedDecimal is given by
significand × 10^{decimalExponent}
where:
significand = wholePart + fractionalPart / 2²⁴

Field Summary

Modifier and Type	Field and Description
private final int	_fractionalPart The fractional part of the significand.
private final int	_relativeDecimalExponent The decimal exponent increased by one less than the digit count of `_wholePart`
private final long	_wholePart The whole part of the significand (typically 15 digits).
private static final BigDecimal	BD_2_POW_24
private static final int	C_2_POW_19 2¹⁹
private static final int	EXPONENT_OFFSET Number of powers of ten contained in the significand
private static final int	FRAC_HALF the value of `_fractionalPart` that represents 0.5
private static final int	LOG_BASE_10_OF_2_TIMES_2_POW_20 log₁₀(2)×2²⁰
private static final long	MAX_REP_WHOLE_PART 10¹⁵

Constructor Summary

Access	Constructor and Description
pack-priv	NormalisedDecimal(long wholePart, int fracPart, int decimalExponent)

Method Summary

Modifier and Type	Method and Description
public int	compareNormalised(NormalisedDecimal other) assumes both this and other are normalised
pack-priv BigInteger	Returns: the significand as a fixed point number (with 24 fraction bits and 47-50 whole bits) composeFrac()
public static NormalisedDecimal	create(BigInteger frac, int binaryExponent)
public int	Returns: the number of powers of 10 which have been extracted from the significand and binary exponent. getDecimalExponent()
private String	getFractionalDigits()
public BigDecimal	getFractionalPart()
public String	getSignificantDecimalDigits()
public String	getSignificantDecimalDigitsLastDigitRounded() Rounds the first whole digit position (considers only units digit, not frational part).
public ExpandedDouble	Returns: a new NormalisedDecimal normalised to base 2 representation. normaliseBaseTwo() Convert to an equivalent `ExpandedDouble` representation (binary frac and exponent).
public NormalisedDecimal	roundUnits() Rounds at the digit with value 10^{decimalExponent}
public String	toString() Overrides java.lang.Object.toString. Returns a string representation of the object.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll wait wait wait

Field Detail

_fractionalPart	back to summary
private final int _fractionalPart The fractional part of the significand. 24 bits (only top 14-17 bits significant): a value between 0x000000 and 0xFFFF80

_relativeDecimalExponent	back to summary
private final int _relativeDecimalExponent The decimal exponent increased by one less than the digit count of `_wholePart`

_wholePart	back to summary
private final long _wholePart The whole part of the significand (typically 15 digits). 47-50 bits long (MSB may be anywhere from bit 46 to 49) LSB is units bit.

BD_2_POW_24	back to summary
private static final BigDecimal BD_2_POW_24

C_2_POW_19	back to summary
private static final int C_2_POW_19 2¹⁹

EXPONENT_OFFSET	back to summary
private static final int EXPONENT_OFFSET Number of powers of ten contained in the significand

FRAC_HALF	back to summary
private static final int FRAC_HALF the value of `_fractionalPart` that represents 0.5

LOG_BASE_10_OF_2_TIMES_2_POW_20	back to summary
private static final int LOG_BASE_10_OF_2_TIMES_2_POW_20 log₁₀(2)×2²⁰

MAX_REP_WHOLE_PART	back to summary
private static final long MAX_REP_WHOLE_PART 10¹⁵

Constructor Detail

NormalisedDecimal	back to summary
pack-priv NormalisedDecimal(long wholePart, int fracPart, int decimalExponent)

Method Detail

compareNormalised	back to summary
public int compareNormalised(NormalisedDecimal other) assumes both this and other are normalised

composeFrac	back to summary
pack-priv BigInteger composeFrac() Returns:BigInteger the significand as a fixed point number (with 24 fraction bits and 47-50 whole bits)

create	back to summary
public static NormalisedDecimal create(BigInteger frac, int binaryExponent) Annotations @SuppressWarnings:java:S128

getDecimalExponent	back to summary
public int getDecimalExponent() Returns:int the number of powers of 10 which have been extracted from the significand and binary exponent.

getFractionalDigits	back to summary
private String getFractionalDigits()

getFractionalPart	back to summary
public BigDecimal getFractionalPart()

getSignificantDecimalDigits	back to summary
public String getSignificantDecimalDigits()

getSignificantDecimalDigitsLastDigitRounded	back to summary
public String getSignificantDecimalDigitsLastDigitRounded() Rounds the first whole digit position (considers only units digit, not frational part). Caller should check total digit count of result to see whether the rounding operation caused a carry out of the most significant digit

normaliseBaseTwo back to summary

normaliseBaseTwo	back to summary
public ExpandedDouble normaliseBaseTwo() Convert to an equivalent `ExpandedDouble` representation (binary frac and exponent). The resulting transformed object is easily converted to a 64 bit IEEE double: bits 2-53 of the `composeFrac()` become the 52 bit 'fraction'. `getDecimalExponent()` is biased by 1023 to give the 'exponent'. The sign bit must be obtained from somewhere else. Returns:ExpandedDouble a new NormalisedDecimal normalised to base 2 representation.

public ExpandedDouble normaliseBaseTwo()

Convert to an equivalent ExpandedDouble representation (binary frac and exponent). The resulting transformed object is easily converted to a 64 bit IEEE double:

bits 2-53 of the composeFrac() become the 52 bit 'fraction'.
getDecimalExponent() is biased by 1023 to give the 'exponent'.

The sign bit must be obtained from somewhere else.

Returns:ExpandedDouble: a new NormalisedDecimal normalised to base 2 representation.

roundUnits	back to summary
public NormalisedDecimal roundUnits() Rounds at the digit with value 10^{decimalExponent}

toString back to summary

toString	back to summary
public String toString() Overrides java.lang.Object.toString. Doc from java.lang.Object.toString. Returns a string representation of the object. Satisfying this method's contract implies a non-`null` result must be returned. Returns:String a string representation of the object Annotations @Override

public String toString()

Overrides java.lang.Object.toString.

Doc from java.lang.Object.toString.

Returns a string representation of the object. Satisfying this method's contract implies a non-null result must be returned.

Returns:String

a string representation of the object

Annotations

@Override