/*
* Copyright (c) 1996, 2014, Oracle and/or its affiliates. All rights reserved.
* ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*
*
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/*
* (C) Copyright Taligent, Inc. 1996, 1997 - All Rights Reserved
* (C) Copyright IBM Corp. 1996 - 1998 - All Rights Reserved
*
* The original version of this source code and documentation is copyrighted
* and owned by Taligent, Inc., a wholly-owned subsidiary of IBM. These
* materials are provided under terms of a License Agreement between Taligent
* and Sun. This technology is protected by multiple US and International
* patents. This notice and attribution to Taligent may not be removed.
* Taligent is a registered trademark of Taligent, Inc.
*
*/
package java.text;
import java.math.
BigDecimal;
import java.math.
BigInteger;
import java.math.
RoundingMode;
import sun.misc.
FloatingDecimal;
/**
* Digit List. Private to DecimalFormat.
* Handles the transcoding
* between numeric values and strings of characters. Only handles
* non-negative numbers. The division of labor between DigitList and
* DecimalFormat is that DigitList handles the radix 10 representation
* issues; DecimalFormat handles the locale-specific issues such as
* positive/negative, grouping, decimal point, currency, and so on.
*
* A DigitList is really a representation of a floating point value.
* It may be an integer value; we assume that a double has sufficient
* precision to represent all digits of a long.
*
* The DigitList representation consists of a string of characters,
* which are the digits radix 10, from '0' to '9'. It also has a radix
* 10 exponent associated with it. The value represented by a DigitList
* object can be computed by mulitplying the fraction f, where 0 <= f < 1,
* derived by placing all the digits of the list to the right of the
* decimal point, by 10^exponent.
*
* @see Locale
* @see Format
* @see NumberFormat
* @see DecimalFormat
* @see ChoiceFormat
* @see MessageFormat
* @author Mark Davis, Alan Liu
*/
final class
DigitList implements
Cloneable {
/**
* The maximum number of significant digits in an IEEE 754 double, that
* is, in a Java double. This must not be increased, or garbage digits
* will be generated, and should not be decreased, or accuracy will be lost.
*/
public static final int
MAX_COUNT = 19; // == Long.toString(Long.MAX_VALUE).length()
/**
* These data members are intentionally public and can be set directly.
*
* The value represented is given by placing the decimal point before
* digits[decimalAt]. If decimalAt is < 0, then leading zeros between
* the decimal point and the first nonzero digit are implied. If decimalAt
* is > count, then trailing zeros between the digits[count-1] and the
* decimal point are implied.
*
* Equivalently, the represented value is given by f * 10^decimalAt. Here
* f is a value 0.1 <= f < 1 arrived at by placing the digits in Digits to
* the right of the decimal.
*
* DigitList is normalized, so if it is non-zero, figits[0] is non-zero. We
* don't allow denormalized numbers because our exponent is effectively of
* unlimited magnitude. The count value contains the number of significant
* digits present in digits[].
*
* Zero is represented by any DigitList with count == 0 or with each digits[i]
* for all i <= count == '0'.
*/
public int
decimalAt = 0;
public int
count = 0;
public char[]
digits = new char[
MAX_COUNT];
private char[]
data;
private
RoundingMode roundingMode =
RoundingMode.
HALF_EVEN;
private boolean
isNegative = false;
/**
* Return true if the represented number is zero.
*/
boolean
isZero() {
for (int
i=0;
i <
count; ++
i) {
if (
digits[
i] != '0') {
return false;
}
}
return true;
}
/**
* Set the rounding mode
*/
void
setRoundingMode(
RoundingMode r) {
roundingMode =
r;
}
/**
* Clears out the digits.
* Use before appending them.
* Typically, you set a series of digits with append, then at the point
* you hit the decimal point, you set myDigitList.decimalAt = myDigitList.count;
* then go on appending digits.
*/
public void
clear () {
decimalAt = 0;
count = 0;
}
/**
* Appends a digit to the list, extending the list when necessary.
*/
public void
append(char
digit) {
if (
count ==
digits.length) {
char[]
data = new char[
count + 100];
System.
arraycopy(
digits, 0,
data, 0,
count);
digits =
data;
}
digits[
count++] =
digit;
}
/**
* Utility routine to get the value of the digit list
* If (count == 0) this throws a NumberFormatException, which
* mimics Long.parseLong().
*/
public final double
getDouble() {
if (
count == 0) {
return 0.0;
}
StringBuffer temp =
getStringBuffer();
temp.
append('.');
temp.
append(
digits, 0,
count);
temp.
append('E');
temp.
append(
decimalAt);
return
Double.
parseDouble(
temp.
toString());
}
/**
* Utility routine to get the value of the digit list.
* If (count == 0) this returns 0, unlike Long.parseLong().
*/
public final long
getLong() {
// for now, simple implementation; later, do proper IEEE native stuff
if (
count == 0) {
return 0;
}
// We have to check for this, because this is the one NEGATIVE value
// we represent. If we tried to just pass the digits off to parseLong,
// we'd get a parse failure.
if (
isLongMIN_VALUE()) {
return
Long.
MIN_VALUE;
}
StringBuffer temp =
getStringBuffer();
temp.
append(
digits, 0,
count);
for (int
i =
count;
i <
decimalAt; ++
i) {
temp.
append('0');
}
return
Long.
parseLong(
temp.
toString());
}
public final
BigDecimal getBigDecimal() {
if (
count == 0) {
if (
decimalAt == 0) {
return
BigDecimal.
ZERO;
} else {
return new
BigDecimal("0E" +
decimalAt);
}
}
if (
decimalAt ==
count) {
return new
BigDecimal(
digits, 0,
count);
} else {
return new
BigDecimal(
digits, 0,
count).
scaleByPowerOfTen(
decimalAt -
count);
}
}
/**
* Return true if the number represented by this object can fit into
* a long.
* @param isPositive true if this number should be regarded as positive
* @param ignoreNegativeZero true if -0 should be regarded as identical to
* +0; otherwise they are considered distinct
* @return true if this number fits into a Java long
*/
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) {
char
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;
}
/**
* Set the digit list to a representation of the given double value.
* This method supports fixed-point notation.
* @param isNegative Boolean value indicating whether the number is negative.
* @param source Value to be converted; must not be Inf, -Inf, Nan,
* or a value <= 0.
* @param maximumFractionDigits The most fractional digits which should
* be converted.
*/
final void
set(boolean
isNegative, double
source, int
maximumFractionDigits) {
set(
isNegative,
source,
maximumFractionDigits, true);
}
/**
* Set the digit list to a representation of the given double value.
* This method supports both fixed-point and exponential notation.
* @param isNegative Boolean value indicating whether the number is negative.
* @param source Value to be converted; must not be Inf, -Inf, Nan,
* or a value <= 0.
* @param maximumDigits The most fractional or total digits which should
* be converted.
* @param fixedPoint If true, then maximumDigits is the maximum
* fractional digits to be converted. If false, total digits.
*/
final void
set(boolean
isNegative, double
source, int
maximumDigits, boolean
fixedPoint) {
FloatingDecimal.
BinaryToASCIIConverter fdConverter =
FloatingDecimal.
getBinaryToASCIIConverter(
source);
boolean
hasBeenRoundedUp =
fdConverter.
digitsRoundedUp();
boolean
valueExactAsDecimal =
fdConverter.
decimalDigitsExact();
assert !
fdConverter.
isExceptional();
String digitsString =
fdConverter.
toJavaFormatString();
set(
isNegative,
digitsString,
hasBeenRoundedUp,
valueExactAsDecimal,
maximumDigits,
fixedPoint);
}
/**
* Generate a representation of the form DDDDD, DDDDD.DDDDD, or
* DDDDDE+/-DDDDD.
* @param roundedUp whether or not rounding up has already happened.
* @param valueExactAsDecimal whether or not collected digits provide
* an exact decimal representation of the value.
*/
private void
set(boolean
isNegative,
String s,
boolean
roundedUp, boolean
valueExactAsDecimal,
int
maximumDigits, boolean
fixedPoint) {
this.
isNegative =
isNegative;
int
len =
s.
length();
char[]
source =
getDataChars(
len);
s.
getChars(0,
len,
source, 0);
decimalAt = -1;
count = 0;
int
exponent = 0;
// Number of zeros between decimal point and first non-zero digit after
// decimal point, for numbers < 1.
int
leadingZerosAfterDecimal = 0;
boolean
nonZeroDigitSeen = false;
for (int
i = 0;
i <
len; ) {
char
c =
source[
i++];
if (
c == '.') {
decimalAt =
count;
} else if (
c == 'e' ||
c == 'E') {
exponent =
parseInt(
source,
i,
len);
break;
} else {
if (!
nonZeroDigitSeen) {
nonZeroDigitSeen = (
c != '0');
if (!
nonZeroDigitSeen &&
decimalAt != -1)
++
leadingZerosAfterDecimal;
}
if (
nonZeroDigitSeen) {
digits[
count++] =
c;
}
}
}
if (
decimalAt == -1) {
decimalAt =
count;
}
if (
nonZeroDigitSeen) {
decimalAt +=
exponent -
leadingZerosAfterDecimal;
}
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 trailing zeros.
while (
count > 1 &&
digits[
count - 1] == '0') {
--
count;
}
// Eliminate digits beyond maximum digits to be displayed.
// Round up if appropriate.
round(
fixedPoint ? (
maximumDigits +
decimalAt) :
maximumDigits,
roundedUp,
valueExactAsDecimal);
}
/**
* Round the representation to the given number of digits.
* @param maximumDigits The maximum number of digits to be shown.
* @param alreadyRounded whether or not rounding up has already happened.
* @param valueExactAsDecimal whether or not collected digits provide
* an exact decimal representation of the value.
*
* Upon return, count will be less than or equal to maximumDigits.
*/
private final 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 up involved incrementing digits from LSD to MSD.
// In most cases this is simple, but in a worst case situation
// (9999..99) we have to adjust the decimalAt value.
for (;;) {
--
maximumDigits;
if (
maximumDigits < 0) {
// We have all 9's, so we increment to a single digit
// of one and adjust the exponent.
digits[0] = '1';
++
decimalAt;
maximumDigits = 0; // Adjust the count
break;
}
++
digits[
maximumDigits];
if (
digits[
maximumDigits] <= '9') break;
// digits[maximumDigits] = '0'; // Unnecessary since we'll truncate this
}
++
maximumDigits; // Increment for use as count
}
count =
maximumDigits;
// Eliminate trailing zeros.
while (
count > 1 &&
digits[
count-1] == '0') {
--
count;
}
}
}
/**
* Return true if truncating the representation to the given number
* of digits will result in an increment to the last digit. This
* method implements the rounding modes defined in the
* java.math.RoundingMode class.
* [bnf]
* @param maximumDigits the number of digits to keep, from 0 to
* <code>count-1</code>. If 0, then all digits are rounded away, and
* this method returns true if a one should be generated (e.g., formatting
* 0.09 with "#.#").
* @param alreadyRounded whether or not rounding up has already happened.
* @param valueExactAsDecimal whether or not collected digits provide
* an exact decimal representation of the value.
* @exception ArithmeticException if rounding is needed with rounding
* mode being set to RoundingMode.UNNECESSARY
* @return true if digit <code>maximumDigits-1</code> should be
* incremented
*/
private boolean
shouldRoundUp(int
maximumDigits,
boolean
alreadyRounded,
boolean
valueExactAsDecimal) {
if (
maximumDigits <
count) {
/*
* To avoid erroneous double-rounding or truncation when converting
* a binary double value to text, information about the exactness
* of the conversion result in FloatingDecimal, as well as any
* rounding done, is needed in this class.
*
* - For the HALF_DOWN, HALF_EVEN, HALF_UP rounding rules below:
* In the case of formating float or double, We must take into
* account what FloatingDecimal has done in the binary to decimal
* conversion.
*
* Considering the tie cases, FloatingDecimal may round up the
* value (returning decimal digits equal to tie when it is below),
* or "truncate" the value to the tie while value is above it,
* or provide the exact decimal digits when the binary value can be
* converted exactly to its decimal representation given formating
* rules of FloatingDecimal ( we have thus an exact decimal
* representation of the binary value).
*
* - If the double binary value was converted exactly as a decimal
* value, then DigitList code must apply the expected rounding
* rule.
*
* - If FloatingDecimal already rounded up the decimal value,
* DigitList should neither round up the value again in any of
* the three rounding modes above.
*
* - If FloatingDecimal has truncated the decimal value to
* an ending '5' digit, DigitList should round up the value in
* all of the three rounding modes above.
*
*
* This has to be considered only if digit at maximumDigits index
* is exactly the last one in the set of digits, otherwise there are
* remaining digits after that position and we don't have to consider
* what FloatingDecimal did.
*
* - Other rounding modes are not impacted by these tie cases.
*
* - For other numbers that are always converted to exact digits
* (like BigInteger, Long, ...), the passed alreadyRounded boolean
* have to be set to false, and valueExactAsDecimal has to be set to
* true in the upper DigitList call stack, providing the right state
* for those situations..
*/
switch(
roundingMode) {
case
UP:
for (int
i=
maximumDigits;
i<
count; ++
i) {
if (
digits[
i] != '0') {
return true;
}
}
break;
case
DOWN:
break;
case
CEILING:
for (int
i=
maximumDigits;
i<
count; ++
i) {
if (
digits[
i] != '0') {
return !
isNegative;
}
}
break;
case
FLOOR:
for (int
i=
maximumDigits;
i<
count; ++
i) {
if (
digits[
i] != '0') {
return
isNegative;
}
}
break;
case
HALF_UP:
case
HALF_DOWN:
if (
digits[
maximumDigits] > '5') {
// Value is above tie ==> must round up
return true;
} else if (
digits[
maximumDigits] == '5') {
// Digit at rounding position is a '5'. Tie cases.
if (
maximumDigits != (
count - 1)) {
// There are remaining digits. Above tie => must round up
return true;
} else {
// Digit at rounding position is the last one !
if (
valueExactAsDecimal) {
// Exact binary representation. On the tie.
// Apply rounding given by roundingMode.
return
roundingMode ==
RoundingMode.
HALF_UP;
} else {
// Not an exact binary representation.
// Digit sequence either rounded up or truncated.
// Round up only if it was truncated.
return !
alreadyRounded;
}
}
}
// Digit at rounding position is < '5' ==> no round up.
// Just let do the default, which is no round up (thus break).
break;
case
HALF_EVEN:
// Implement IEEE half-even rounding
if (
digits[
maximumDigits] > '5') {
return true;
} else if (
digits[
maximumDigits] == '5' ) {
if (
maximumDigits == (
count - 1)) {
// the rounding position is exactly the last index :
if (
alreadyRounded)
// If FloatingDecimal rounded up (value was below tie),
// then we should not round up again.
return false;
if (!
valueExactAsDecimal)
// Otherwise if the digits don't represent exact value,
// value was above tie and FloatingDecimal truncated
// digits to tie. We must round up.
return true;
else {
// This is an exact tie value, and FloatingDecimal
// provided all of the exact digits. We thus apply
// HALF_EVEN rounding rule.
return ((
maximumDigits > 0) &&
(
digits[
maximumDigits-1] % 2 != 0));
}
} else {
// Rounds up if it gives a non null digit after '5'
for (int
i=
maximumDigits+1;
i<
count; ++
i) {
if (
digits[
i] != '0')
return true;
}
}
}
break;
case
UNNECESSARY:
for (int
i=
maximumDigits;
i<
count; ++
i) {
if (
digits[
i] != '0') {
throw new
ArithmeticException(
"Rounding needed with the rounding mode being set to RoundingMode.UNNECESSARY");
}
}
break;
default:
assert false;
}
}
return false;
}
/**
* Utility routine to set the value of the digit list from a long
*/
final void
set(boolean
isNegative, long
source) {
set(
isNegative,
source, 0);
}
/**
* Set the digit list to a representation of the given long value.
* @param isNegative Boolean value indicating whether the number is negative.
* @param source Value to be converted; must be >= 0 or ==
* Long.MIN_VALUE.
* @param maximumDigits The most digits which should be converted.
* If maximumDigits is lower than the number of significant digits
* in source, the representation will be rounded. Ignored if <= 0.
*/
final 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] = (char)('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.
for (
right =
MAX_COUNT - 1;
digits[
right] == '0'; --
right)
;
count =
right -
left + 1;
System.
arraycopy(
digits,
left,
digits, 0,
count);
}
if (
maximumDigits > 0)
round(
maximumDigits, false, true);
}
/**
* Set the digit list to a representation of the given BigDecimal value.
* This method supports both fixed-point and exponential notation.
* @param isNegative Boolean value indicating whether the number is negative.
* @param source Value to be converted; must not be a value <= 0.
* @param maximumDigits The most fractional or total digits which should
* be converted.
* @param fixedPoint If true, then maximumDigits is the maximum
* fractional digits to be converted. If false, total digits.
*/
final void
set(boolean
isNegative,
BigDecimal source, int
maximumDigits, boolean
fixedPoint) {
String s =
source.
toString();
extendDigits(
s.
length());
set(
isNegative,
s,
false, true,
maximumDigits,
fixedPoint);
}
/**
* Set the digit list to a representation of the given BigInteger value.
* @param isNegative Boolean value indicating whether the number is negative.
* @param source Value to be converted; must be >= 0.
* @param maximumDigits The most digits which should be converted.
* If maximumDigits is lower than the number of significant digits
* in source, the representation will be rounded. Ignored if <= 0.
*/
final void
set(boolean
isNegative,
BigInteger source, int
maximumDigits) {
this.
isNegative =
isNegative;
String s =
source.
toString();
int
len =
s.
length();
extendDigits(
len);
s.
getChars(0,
len,
digits, 0);
decimalAt =
len;
int
right;
for (
right =
len - 1;
right >= 0 &&
digits[
right] == '0'; --
right)
;
count =
right + 1;
if (
maximumDigits > 0) {
round(
maximumDigits, false, true);
}
}
/**
* equality test between two digit lists.
*/
public boolean
equals(
Object obj) {
if (this ==
obj) // quick check
return true;
if (!(
obj instanceof
DigitList)) // (1) same object?
return false;
DigitList other = (
DigitList)
obj;
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;
}
/**
* Generates the hash code for the digit list.
*/
public int
hashCode() {
int
hashcode =
decimalAt;
for (int
i = 0;
i <
count;
i++) {
hashcode =
hashcode * 37 +
digits[
i];
}
return
hashcode;
}
/**
* Creates a copy of this object.
* @return a clone of this instance.
*/
public
Object clone() {
try {
DigitList other = (
DigitList) super.clone();
char[]
newDigits = new char[
digits.length];
System.
arraycopy(
digits, 0,
newDigits, 0,
digits.length);
other.
digits =
newDigits;
other.
tempBuffer = null;
return
other;
} catch (
CloneNotSupportedException e) {
throw new
InternalError(
e);
}
}
/**
* Returns true if this DigitList represents Long.MIN_VALUE;
* false, otherwise. This is required so that getLong() works.
*/
private boolean
isLongMIN_VALUE() {
if (
decimalAt !=
count ||
count !=
MAX_COUNT) {
return false;
}
for (int
i = 0;
i <
count; ++
i) {
if (
digits[
i] !=
LONG_MIN_REP[
i]) return false;
}
return true;
}
private static final int
parseInt(char[]
str, int
offset, int
strLen) {
char
c;
boolean
positive = true;
if ((
c =
str[
offset]) == '-') {
positive = false;
offset++;
} else if (
c == '+') {
offset++;
}
int
value = 0;
while (
offset <
strLen) {
c =
str[
offset++];
if (
c >= '0' &&
c <= '9') {
value =
value * 10 + (
c - '0');
} else {
break;
}
}
return
positive ?
value : -
value;
}
// The digit part of -9223372036854775808L
private static final char[]
LONG_MIN_REP = "9223372036854775808".
toCharArray();
public
String toString() {
if (
isZero()) {
return "0";
}
StringBuffer buf =
getStringBuffer();
buf.
append("0.");
buf.
append(
digits, 0,
count);
buf.
append("x10^");
buf.
append(
decimalAt);
return
buf.
toString();
}
private
StringBuffer tempBuffer;
private
StringBuffer getStringBuffer() {
if (
tempBuffer == null) {
tempBuffer = new
StringBuffer(
MAX_COUNT);
} else {
tempBuffer.
setLength(0);
}
return
tempBuffer;
}
private void
extendDigits(int
len) {
if (
len >
digits.length) {
digits = new char[
len];
}
}
private final char[]
getDataChars(int
length) {
if (
data == null ||
data.length <
length) {
data = new char[
length];
}
return
data;
}
}