/**

public static final int MAX_COUNT = 19; // == Long.toString(Long.MAX_VALUE).length()

/**

public int decimalAt = 0;

public int count = 0;

public byte[] digits = new byte[MAX_COUNT];

private RoundingMode roundingMode = RoundingMode.HALF_EVEN;

private boolean isNegative = false;

/**

boolean isZero() {

return !nonZeroAfterIndex(0);

}

/**

private boolean nonZeroAfterIndex(int index) {

for (int i=index; i < count; ++i) {

if (digits[i] != '0') {

return true;

}

}

return false;

}

/**

void setRoundingMode(RoundingMode r) {

roundingMode = r;

}

/**

public void clear () {

decimalAt = 0;

count = 0;

}

/**

public void append(char digit) {

if (count == digits.length) {

byte[] data = new byte[ArraysSupport.newLength(count, 1, count)];

System.arraycopy(digits, 0, data, 0, count);

digits = data;

}

digits[count++] = (byte) digit;

}

/**

public double getDouble() {

if (count == 0) {

return 0.0;

}

return FloatingDecimal.parseDoubleSignlessDigits(decimalAt, digits, count);

}

/**

public long getLong() {

// for now, simple implementation; later, do proper IEEE native stuff

if (count == 0) {

return 0;

}

// Parse as unsigned to handle Long.MIN_VALUE, which is the one NEGATIVE value

// we represent. If we tried to just pass the digits off to parseLong,

// we'd get a parse failure.

long v = Long.parseUnsignedLong(new String(digits, 0, count, StandardCharsets.ISO_8859_1));

if (v < 0) {

if (v == Long.MIN_VALUE) {

return Long.MIN_VALUE;

}

throw new NumberFormatException("Unexpected negative value");

}

try {

long pow10 = Math.powExact(10L, Math.max(0, decimalAt - count));

return Math.multiplyExact(v, pow10);

} catch (ArithmeticException e) {

throw new NumberFormatException("Value does not fit into a long");

}

}

/**

public BigDecimal getBigDecimal() {

int count = this.count;

if (count == 0) {

return BigDecimal.valueOf(0, -decimalAt);

}

char[] chars = new char[count];

SharedSecrets.getJavaLangAccess()

.inflateBytesToChars(digits, 0, chars, 0, count);

BigDecimal value = new BigDecimal(chars, 0, count);

if (decimalAt == count) {

return value;

} else {

return value.scaleByPowerOfTen(decimalAt - count);

}

}

/**

boolean fitsIntoLong(boolean isPositive, boolean ignoreNegativeZero) {

// Figure out if the result will fit in a long. We have to

// first look for nonzero digits after the decimal point;

// then check the size. If the digit count is 18 or less, then

// the value can definitely be represented as a long. If it is 19

// then it may be too large.

// Trim trailing zeros. This does not change the represented value.

while (count > 0 && digits[count - 1] == '0') {

--count;

}

if (count == 0) {

// Positive zero fits into a long, but negative zero can only

// be represented as a double. - bug 4162852

return isPositive || ignoreNegativeZero;

}

if (decimalAt < count || decimalAt > MAX_COUNT) {

return false;

}

if (decimalAt < MAX_COUNT) return true;

// At this point we have decimalAt == count, and count == MAX_COUNT.

// The number will overflow if it is larger than 9223372036854775807

// or smaller than -9223372036854775808.

for (int i=0; i<count; ++i) {

byte dig = digits[i], max = LONG_MIN_REP[i];

if (dig > max) return false;

if (dig < max) return true;

}

// At this point the first count digits match. If decimalAt is less

// than count, then the remaining digits are zero, and we return true.

if (count < decimalAt) return true;

// Now we have a representation of Long.MIN_VALUE, without the leading

// negative sign. If this represents a positive value, then it does

// not fit; otherwise it fits.

return !isPositive;

}

/**

void set(boolean isNegative, double source, int maximumFractionDigits) {

set(isNegative, source, maximumFractionDigits, true);

}

/*

private static final boolean COMPAT = Boolean.getBoolean("jdk.compat.DecimalFormat");

/**

void set(boolean isNegative, double source, int maximumDigits, boolean fixedPoint) {

assert Double.isFinite(source);

FloatingDecimal.BinaryToASCIIBuffer fdConverter =

FloatingDecimal.getBinaryToASCIIConverter(source, COMPAT);

boolean hasBeenRoundedUp = fdConverter.digitsRoundedUp();

boolean valueExactAsDecimal = fdConverter.decimalDigitsExact();

count = fdConverter.getDigits(digits);

int exp = fdConverter.getDecimalExponent() - count;

set(isNegative, exp,

hasBeenRoundedUp, valueExactAsDecimal,

maximumDigits, fixedPoint);

}

/**

private void set(boolean isNegative, int exp,

boolean roundedUp, boolean valueExactAsDecimal,

int maximumDigits, boolean fixedPoint) {

this.isNegative = isNegative;

if (!nonZeroAfterIndex(0)) {

count = 0;

decimalAt = 0;

return;

}

decimalAt = count + exp;

// Eliminate trailing zeros.

while (count > 1 && digits[count - 1] == '0') {

--count;

}

if (fixedPoint) {

// The negative of the exponent represents the number of leading

// zeros between the decimal and the first non-zero digit, for

// a value < 0.1 (e.g., for 0.00123, -decimalAt == 2). If this

// is more than the maximum fraction digits, then we have an underflow

// for the printed representation.

if (-decimalAt > maximumDigits) {

// Handle an underflow to zero when we round something like

// 0.0009 to 2 fractional digits.

count = 0;

return;

} else if (-decimalAt == maximumDigits) {

// If we round 0.0009 to 3 fractional digits, then we have to

// create a new one digit in the least significant location.

if (shouldRoundUp(0, roundedUp, valueExactAsDecimal)) {

count = 1;

++decimalAt;

digits[0] = '1';

} else {

count = 0;

}

return;

}

// else fall through

}

// Eliminate digits beyond maximum digits to be displayed.

// Round up if appropriate.

round(fixedPoint ? (maximumDigits + decimalAt) : maximumDigits,

roundedUp, valueExactAsDecimal);

}

/**

private void roundInt(int maximumDigits) {

// Integers do not need to worry about double rounding

round(maximumDigits, false, true);

}

/**

private void round(int maximumDigits,

boolean alreadyRounded,

boolean valueExactAsDecimal) {

// Eliminate digits beyond maximum digits to be displayed.

// Round up if appropriate.

if (maximumDigits >= 0 && maximumDigits < count) {

if (shouldRoundUp(maximumDigits, alreadyRounded, valueExactAsDecimal)) {

// Rounding can adjust the max digits

maximumDigits = roundUp(maximumDigits);

}

count = maximumDigits;

// Eliminate trailing zeros.

while (count > 1 && digits[count-1] == '0') {

--count;

}

}

}

/**

private boolean shouldRoundUp(int maximumDigits,

boolean alreadyRounded,

boolean valueExactAsDecimal) {

if (maximumDigits < count) {

/*

switch(roundingMode) {

case UP:

return nonZeroAfterIndex(maximumDigits);

case DOWN:

break;

case CEILING:

return nonZeroAfterIndex(maximumDigits) && !isNegative;

case FLOOR:

return nonZeroAfterIndex(maximumDigits) && isNegative;

case HALF_UP:

case HALF_DOWN:

case HALF_EVEN:

// Above tie, round up for all cases

if (digits[maximumDigits] > '5') {

return true;

// At tie, consider UP, DOWN, and EVEN logic

} else if (digits[maximumDigits] == '5' ) {

// Rounding position is the last index, there are 3 Cases.

if (maximumDigits == (count - 1)) {

// When exact, consider specific contract logic

if (valueExactAsDecimal) {

return (roundingMode == RoundingMode.HALF_UP) ||

(roundingMode == RoundingMode.HALF_EVEN

&& (maximumDigits > 0) && (digits[maximumDigits - 1] % 2 != 0));

// If already rounded, do not round again, otherwise round up

} else {

return !alreadyRounded;

}

// Rounding position is not the last index

// If any further digits have a non-zero value, round up

} else {

return nonZeroAfterIndex(maximumDigits+1);

}

}

// Below tie, do not round up for all cases

break;

case UNNECESSARY:

if (nonZeroAfterIndex(maximumDigits)) {

throw new ArithmeticException(

"Rounding needed with the rounding mode being set to RoundingMode.UNNECESSARY");

}

break;

default:

assert false;

}

}

return false;

}

/**

private int roundUp(int maximumDigits) {

do {

--maximumDigits;

/*

if (maximumDigits < 0) {

digits[0] = '1';

++decimalAt;

maximumDigits = 0; // Adjust the count

break;

}

++digits[maximumDigits];

}

while (digits[maximumDigits] > '9');

return ++maximumDigits; // Increment for use as count

}

/**

void set(boolean isNegative, long source) {

set(isNegative, source, 0);

}

/**

void set(boolean isNegative, long source, int maximumDigits) {

this.isNegative = isNegative;

// This method does not expect a negative number. However,

// "source" can be a Long.MIN_VALUE (-9223372036854775808),

// if the number being formatted is a Long.MIN_VALUE. In that

// case, it will be formatted as -Long.MIN_VALUE, a number

// which is outside the legal range of a long, but which can

// be represented by DigitList.

if (source <= 0) {

if (source == Long.MIN_VALUE) {

decimalAt = count = MAX_COUNT;

System.arraycopy(LONG_MIN_REP, 0, digits, 0, count);

} else {

decimalAt = count = 0; // Values <= 0 format as zero

}

} else {

// Rewritten to improve performance. I used to call

// Long.toString(), which was about 4x slower than this code.

int left = MAX_COUNT;

int right;

while (source > 0) {

digits[--left] = (byte)('0' + (source % 10));

source /= 10;

}

decimalAt = MAX_COUNT - left;

// Don't copy trailing zeros. We are guaranteed that there is at

// least one non-zero digit, so we don't have to check lower bounds.

right = MAX_COUNT - 1;

while (digits[right] == '0') {

--right;

}

count = right - left + 1;

System.arraycopy(digits, left, digits, 0, count);

}

if (maximumDigits > 0) {

roundInt(maximumDigits);

}

}

/**

@SuppressWarnings("deprecation")

void set(boolean isNegative, BigDecimal source, int maximumDigits, boolean fixedPoint) {

String s = source.unscaledValue().toString();

int len = s.length();

extendDigits(len);

s.getBytes(0, len, digits, 0);

count = len;

set(isNegative, -source.scale(),

false, true,

maximumDigits, fixedPoint);

}

/**

@SuppressWarnings("deprecation")

void set(boolean isNegative, BigInteger source, int maximumDigits) {

this.isNegative = isNegative;

String s = source.toString();

int len = s.length();

extendDigits(len);

s.getBytes(0, len, digits, 0);

decimalAt = len;

int right = len - 1;

while (right >= 0 && digits[right] == '0') {

--right;

}

count = right + 1;

if (maximumDigits > 0) {

roundInt(maximumDigits);

}

}

/**

public boolean equals(Object obj) {

if (this == obj) // quick check

return true;

if (!(obj instanceof DigitList other)) // (1) same object?

return false;

if (count != other.count ||

decimalAt != other.decimalAt)

return false;

for (int i = 0; i < count; i++)

if (digits[i] != other.digits[i])

return false;

return true;

}

/**

public int hashCode() {

int hashcode = decimalAt;

for (int i = 0; i < count; i++) {

hashcode = hashcode * 37 + digits[i];

}

return hashcode;

}

/**

public Object clone() {

try {

DigitList other = (DigitList) super.clone();

other.digits = digits.clone();

return other;

} catch (CloneNotSupportedException e) {

throw new InternalError(e);

}

}

// The digit part of -9223372036854775808L

@Stable

private static final byte[] LONG_MIN_REP = "9223372036854775808".getBytes(StandardCharsets.ISO_8859_1);

public String toString() {

if (isZero()) {

return "0";

}

return "0." + new String(digits, 0, count, StandardCharsets.ISO_8859_1) + "x10^" + decimalAt;

}

private void extendDigits(int len) {

if (len > digits.length) {

digits = new byte[len];

}

}