1 /*
2 * Copyright (c) 1996, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 /*
27 * (C) Copyright Taligent, Inc. 1996, 1997 - All Rights Reserved
28 * (C) Copyright IBM Corp. 1996 - 1998 - All Rights Reserved
29 *
30 * The original version of this source code and documentation is copyrighted
31 * and owned by Taligent, Inc., a wholly-owned subsidiary of IBM. These
32 * materials are provided under terms of a License Agreement between Taligent
33 * and Sun. This technology is protected by multiple US and International
34 * patents. This notice and attribution to Taligent may not be removed.
35 * Taligent is a registered trademark of Taligent, Inc.
36 *
37 */
38
39 package java.text;
40
41 import java.math.BigDecimal;
42 import java.math.BigInteger;
43 import java.math.RoundingMode;
44 import sun.misc.FloatingDecimal;
45
46 /**
47 * Digit List. Private to DecimalFormat.
48 * Handles the transcoding
49 * between numeric values and strings of characters. Only handles
50 * non-negative numbers. The division of labor between DigitList and
51 * DecimalFormat is that DigitList handles the radix 10 representation
52 * issues; DecimalFormat handles the locale-specific issues such as
53 * positive/negative, grouping, decimal point, currency, and so on.
54 *
55 * A DigitList is really a representation of a floating point value.
56 * It may be an integer value; we assume that a double has sufficient
57 * precision to represent all digits of a long.
58 *
59 * The DigitList representation consists of a string of characters,
60 * which are the digits radix 10, from '0' to '9'. It also has a radix
61 * 10 exponent associated with it. The value represented by a DigitList
62 * object can be computed by mulitplying the fraction f, where 0 <= f < 1,
63 * derived by placing all the digits of the list to the right of the
64 * decimal point, by 10^exponent.
65 *
66 * @see Locale
67 * @see Format
68 * @see NumberFormat
69 * @see DecimalFormat
70 * @see ChoiceFormat
71 * @see MessageFormat
72 * @author Mark Davis, Alan Liu
73 */
74 final class DigitList implements Cloneable {
75 /**
76 * The maximum number of significant digits in an IEEE 754 double, that
77 * is, in a Java double. This must not be increased, or garbage digits
78 * will be generated, and should not be decreased, or accuracy will be lost.
79 */
80 public static final int MAX_COUNT = 19; // == Long.toString(Long.MAX_VALUE).length()
81
82 /**
83 * These data members are intentionally public and can be set directly.
84 *
85 * The value represented is given by placing the decimal point before
86 * digits[decimalAt]. If decimalAt is < 0, then leading zeros between
87 * the decimal point and the first nonzero digit are implied. If decimalAt
88 * is > count, then trailing zeros between the digits[count-1] and the
89 * decimal point are implied.
90 *
91 * Equivalently, the represented value is given by f * 10^decimalAt. Here
92 * f is a value 0.1 <= f < 1 arrived at by placing the digits in Digits to
93 * the right of the decimal.
94 *
95 * DigitList is normalized, so if it is non-zero, figits[0] is non-zero. We
96 * don't allow denormalized numbers because our exponent is effectively of
97 * unlimited magnitude. The count value contains the number of significant
98 * digits present in digits[].
99 *
100 * Zero is represented by any DigitList with count == 0 or with each digits[i]
101 * for all i <= count == '0'.
102 */
103 public int decimalAt = 0;
104 public int count = 0;
105 public char[] digits = new char[MAX_COUNT];
106
107 private char[] data;
108 private RoundingMode roundingMode = RoundingMode.HALF_EVEN;
109 private boolean isNegative = false;
110
111 /**
112 * Return true if the represented number is zero.
113 */
114 boolean isZero() {
115 for (int i=0; i < count; ++i) {
116 if (digits[i] != '0') {
117 return false;
118 }
119 }
120 return true;
121 }
122
123 /**
124 * Set the rounding mode
125 */
126 void setRoundingMode(RoundingMode r) {
127 roundingMode = r;
128 }
129
130 /**
131 * Clears out the digits.
132 * Use before appending them.
133 * Typically, you set a series of digits with append, then at the point
134 * you hit the decimal point, you set myDigitList.decimalAt = myDigitList.count;
135 * then go on appending digits.
136 */
137 public void clear () {
138 decimalAt = 0;
139 count = 0;
140 }
141
142 /**
143 * Appends a digit to the list, extending the list when necessary.
144 */
145 public void append(char digit) {
146 if (count == digits.length) {
147 char[] data = new char[count + 100];
148 System.arraycopy(digits, 0, data, 0, count);
149 digits = data;
150 }
151 digits[count++] = digit;
152 }
153
154 /**
155 * Utility routine to get the value of the digit list
156 * If (count == 0) this throws a NumberFormatException, which
157 * mimics Long.parseLong().
158 */
159 public final double getDouble() {
160 if (count == 0) {
161 return 0.0;
162 }
163
164 StringBuffer temp = getStringBuffer();
165 temp.append('.');
166 temp.append(digits, 0, count);
167 temp.append('E');
168 temp.append(decimalAt);
169 return Double.parseDouble(temp.toString());
170 }
171
172 /**
173 * Utility routine to get the value of the digit list.
174 * If (count == 0) this returns 0, unlike Long.parseLong().
175 */
176 public final long getLong() {
177 // for now, simple implementation; later, do proper IEEE native stuff
178
179 if (count == 0) {
180 return 0;
181 }
182
183 // We have to check for this, because this is the one NEGATIVE value
184 // we represent. If we tried to just pass the digits off to parseLong,
185 // we'd get a parse failure.
186 if (isLongMIN_VALUE()) {
187 return Long.MIN_VALUE;
188 }
189
190 StringBuffer temp = getStringBuffer();
191 temp.append(digits, 0, count);
192 for (int i = count; i < decimalAt; ++i) {
193 temp.append('0');
194 }
195 return Long.parseLong(temp.toString());
196 }
197
198 public final BigDecimal getBigDecimal() {
199 if (count == 0) {
200 if (decimalAt == 0) {
201 return BigDecimal.ZERO;
202 } else {
203 return new BigDecimal("0E" + decimalAt);
204 }
205 }
206
207 if (decimalAt == count) {
208 return new BigDecimal(digits, 0, count);
209 } else {
210 return new BigDecimal(digits, 0, count).scaleByPowerOfTen(decimalAt - count);
211 }
212 }
213
214 /**
215 * Return true if the number represented by this object can fit into
216 * a long.
217 * @param isPositive true if this number should be regarded as positive
218 * @param ignoreNegativeZero true if -0 should be regarded as identical to
219 * +0; otherwise they are considered distinct
220 * @return true if this number fits into a Java long
221 */
222 boolean fitsIntoLong(boolean isPositive, boolean ignoreNegativeZero) {
223 // Figure out if the result will fit in a long. We have to
224 // first look for nonzero digits after the decimal point;
225 // then check the size. If the digit count is 18 or less, then
226 // the value can definitely be represented as a long. If it is 19
227 // then it may be too large.
228
229 // Trim trailing zeros. This does not change the represented value.
230 while (count > 0 && digits[count - 1] == '0') {
231 --count;
232 }
233
234 if (count == 0) {
235 // Positive zero fits into a long, but negative zero can only
236 // be represented as a double. - bug 4162852
237 return isPositive || ignoreNegativeZero;
238 }
239
240 if (decimalAt < count || decimalAt > MAX_COUNT) {
241 return false;
242 }
243
244 if (decimalAt < MAX_COUNT) return true;
245
246 // At this point we have decimalAt == count, and count == MAX_COUNT.
247 // The number will overflow if it is larger than 9223372036854775807
248 // or smaller than -9223372036854775808.
249 for (int i=0; i<count; ++i) {
250 char dig = digits[i], max = LONG_MIN_REP[i];
251 if (dig > max) return false;
252 if (dig < max) return true;
253 }
254
255 // At this point the first count digits match. If decimalAt is less
256 // than count, then the remaining digits are zero, and we return true.
257 if (count < decimalAt) return true;
258
259 // Now we have a representation of Long.MIN_VALUE, without the leading
260 // negative sign. If this represents a positive value, then it does
261 // not fit; otherwise it fits.
262 return !isPositive;
263 }
264
265 /**
266 * Set the digit list to a representation of the given double value.
267 * This method supports fixed-point notation.
268 * @param isNegative Boolean value indicating whether the number is negative.
269 * @param source Value to be converted; must not be Inf, -Inf, Nan,
270 * or a value <= 0.
271 * @param maximumFractionDigits The most fractional digits which should
272 * be converted.
273 */
274 final void set(boolean isNegative, double source, int maximumFractionDigits) {
275 set(isNegative, source, maximumFractionDigits, true);
276 }
277
278 /**
279 * Set the digit list to a representation of the given double value.
280 * This method supports both fixed-point and exponential notation.
281 * @param isNegative Boolean value indicating whether the number is negative.
282 * @param source Value to be converted; must not be Inf, -Inf, Nan,
283 * or a value <= 0.
284 * @param maximumDigits The most fractional or total digits which should
285 * be converted.
286 * @param fixedPoint If true, then maximumDigits is the maximum
287 * fractional digits to be converted. If false, total digits.
288 */
289 final void set(boolean isNegative, double source, int maximumDigits, boolean fixedPoint) {
290
291 FloatingDecimal.BinaryToASCIIConverter fdConverter = FloatingDecimal.getBinaryToASCIIConverter(source);
292 boolean hasBeenRoundedUp = fdConverter.digitsRoundedUp();
293 boolean allDecimalDigits = fdConverter.decimalDigitsExact();
294 assert !fdConverter.isExceptional();
295 String digitsString = fdConverter.toJavaFormatString();
296
297 set(isNegative, digitsString,
298 hasBeenRoundedUp, allDecimalDigits,
299 maximumDigits, fixedPoint);
300 }
301
302 /**
303 * Generate a representation of the form DDDDD, DDDDD.DDDDD, or
304 * DDDDDE+/-DDDDD.
305 * @param roundedUp Boolean value indicating if the s digits were rounded-up.
306 * @param allDecimalDigits Boolean value indicating if the digits in s are
307 * an exact decimal representation of the double that was passed.
308 */
309 private void set(boolean isNegative, String s,
310 boolean roundedUp, boolean allDecimalDigits,
311 int maximumDigits, boolean fixedPoint) {
312 this.isNegative = isNegative;
313 int len = s.length();
314 char[] source = getDataChars(len);
315 s.getChars(0, len, source, 0);
316
317 decimalAt = -1;
318 count = 0;
319 int exponent = 0;
320 // Number of zeros between decimal point and first non-zero digit after
321 // decimal point, for numbers < 1.
322 int leadingZerosAfterDecimal = 0;
323 boolean nonZeroDigitSeen = false;
324
325 for (int i = 0; i < len; ) {
326 char c = source[i++];
327 if (c == '.') {
328 decimalAt = count;
329 } else if (c == 'e' || c == 'E') {
330 exponent = parseInt(source, i, len);
331 break;
332 } else {
333 if (!nonZeroDigitSeen) {
334 nonZeroDigitSeen = (c != '0');
335 if (!nonZeroDigitSeen && decimalAt != -1)
336 ++leadingZerosAfterDecimal;
337 }
338 if (nonZeroDigitSeen) {
339 digits[count++] = c;
340 }
341 }
342 }
343 if (decimalAt == -1) {
344 decimalAt = count;
345 }
346 if (nonZeroDigitSeen) {
347 decimalAt += exponent - leadingZerosAfterDecimal;
348 }
349
350 if (fixedPoint) {
351 // The negative of the exponent represents the number of leading
352 // zeros between the decimal and the first non-zero digit, for
353 // a value < 0.1 (e.g., for 0.00123, -decimalAt == 2). If this
354 // is more than the maximum fraction digits, then we have an underflow
355 // for the printed representation.
356 if (-decimalAt > maximumDigits) {
357 // Handle an underflow to zero when we round something like
358 // 0.0009 to 2 fractional digits.
359 count = 0;
360 return;
361 } else if (-decimalAt == maximumDigits) {
362 // If we round 0.0009 to 3 fractional digits, then we have to
363 // create a new one digit in the least significant location.
364 if (shouldRoundUp(0, roundedUp, allDecimalDigits)) {
365 count = 1;
366 ++decimalAt;
367 digits[0] = '1';
368 } else {
369 count = 0;
370 }
371 return;
372 }
373 // else fall through
374 }
375
376 // Eliminate trailing zeros.
377 while (count > 1 && digits[count - 1] == '0') {
378 --count;
379 }
380
381 // Eliminate digits beyond maximum digits to be displayed.
382 // Round up if appropriate.
383 round(fixedPoint ? (maximumDigits + decimalAt) : maximumDigits,
384 roundedUp, allDecimalDigits);
385 }
386
387 /**
388 * Round the representation to the given number of digits.
389 * @param maximumDigits The maximum number of digits to be shown.
390 * @param alreadyRounded Boolean indicating if rounding up already happened.
391 * @param allDecimalDigits Boolean indicating if the digits provide an exact
392 * representation of the value.
393 *
394 * Upon return, count will be less than or equal to maximumDigits.
395 */
396 private final void round(int maximumDigits,
397 boolean alreadyRounded,
398 boolean allDecimalDigits) {
399 // Eliminate digits beyond maximum digits to be displayed.
400 // Round up if appropriate.
401 if (maximumDigits >= 0 && maximumDigits < count) {
402 if (shouldRoundUp(maximumDigits, alreadyRounded, allDecimalDigits)) {
403 // Rounding up involved incrementing digits from LSD to MSD.
404 // In most cases this is simple, but in a worst case situation
405 // (9999..99) we have to adjust the decimalAt value.
406 for (;;) {
407 --maximumDigits;
408 if (maximumDigits < 0) {
409 // We have all 9's, so we increment to a single digit
410 // of one and adjust the exponent.
411 digits[0] = '1';
412 ++decimalAt;
413 maximumDigits = 0; // Adjust the count
414 break;
415 }
416
417 ++digits[maximumDigits];
418 if (digits[maximumDigits] <= '9') break;
419 // digits[maximumDigits] = '0'; // Unnecessary since we'll truncate this
420 }
421 ++maximumDigits; // Increment for use as count
422 }
423 count = maximumDigits;
424
425 // Eliminate trailing zeros.
426 while (count > 1 && digits[count-1] == '0') {
427 --count;
428 }
429 }
430 }
431
432
433 /**
434 * Return true if truncating the representation to the given number
435 * of digits will result in an increment to the last digit. This
436 * method implements the rounding modes defined in the
437 * java.math.RoundingMode class.
438 * [bnf]
439 * @param maximumDigits the number of digits to keep, from 0 to
440 * <code>count-1</code>. If 0, then all digits are rounded away, and
441 * this method returns true if a one should be generated (e.g., formatting
442 * 0.09 with "#.#").
443 * @exception ArithmeticException if rounding is needed with rounding
444 * mode being set to RoundingMode.UNNECESSARY
445 * @return true if digit <code>maximumDigits-1</code> should be
446 * incremented
447 */
448 private boolean shouldRoundUp(int maximumDigits,
449 boolean alreadyRounded,
450 boolean allDecimalDigits) {
451 if (maximumDigits < count) {
452 /*
453 * To avoid erroneous double-rounding or truncation when converting
454 * a binary double value to text, information about the exactness
455 * of the conversion result in FloatingDecimal, as well as any
456 * rounding done, is needed in this class.
457 *
458 * - For the HALF_DOWN, HALF_EVEN, HALF_UP rounding rules below:
459 * In the case of formating float or double, We must take into
460 * account what FloatingDecimal has done in the binary to decimal
461 * conversion.
462 *
463 * Considering the tie cases, FloatingDecimal may round-up the
464 * value (returning decimal digits equal to tie when it is below),
465 * or "truncate" the value to the tie while value is above it,
466 * or provide the exact decimal digits when the binary value can be
467 * converted exactly to its decimal representation given formating
468 * rules of FloatingDecimal ( we have thus an exact decimal
469 * representation of the binary value).
470 *
471 * - If the double binary value was converted exactly as a decimal
472 * value, then DigitList code must apply the expected rounding
473 * rule.
474 *
475 * - If FloatingDecimal already rounded up the decimal value,
476 * DigitList should neither round up the value again in any of
477 * the three rounding modes above.
478 *
479 * - If FloatingDecimal has truncated the decimal value to
480 * an ending '5' digit, DigitList should round up the value in
481 * all of the three rounding modes above.
482 *
483 *
484 * This has to be considered only if digit at maximumDigits index
485 * is exactly the last one in the set of digits, otherwise there are
486 * remaining digits after that position and we don't have to consider
487 * what FloatingDecimal did.
488 *
489 * - Other rounding modes are not impacted by these tie cases.
490 *
491 * - For other numbers that are always converted to exact digits
492 * (like BigInteger, Long, ...), the passed alreadyRounded boolean
493 * have to be set to false, and allDecimalDigits has to be set to
494 * true in the upper DigitList call stack, providing the right state
495 * for those situations..
496 */
497
498 switch(roundingMode) {
499 case UP:
500 for (int i=maximumDigits; i<count; ++i) {
501 if (digits[i] != '0') {
502 return true;
503 }
504 }
505 break;
506 case DOWN:
507 break;
508 case CEILING:
509 for (int i=maximumDigits; i<count; ++i) {
510 if (digits[i] != '0') {
511 return !isNegative;
512 }
513 }
514 break;
515 case FLOOR:
516 for (int i=maximumDigits; i<count; ++i) {
517 if (digits[i] != '0') {
518 return isNegative;
519 }
520 }
521 break;
522 case HALF_UP:
523 if (digits[maximumDigits] >= '5') {
524 // We should not round up if the rounding digits position is
525 // exactly the last index and if digits were already rounded.
526 if ((maximumDigits == (count - 1)) &&
527 (alreadyRounded))
528 return false;
529
530 // Value was exactly at or was above tie. We must round up.
531 return true;
532 }
533 break;
534 case HALF_DOWN:
535 if (digits[maximumDigits] > '5') {
536 return true;
537 } else if (digits[maximumDigits] == '5' ) {
538 if (maximumDigits == (count - 1)) {
539 // The rounding position is exactly the last index.
540 if (allDecimalDigits || alreadyRounded)
541 /* FloatingDecimal rounded up (value was below tie),
542 * or provided the exact list of digits (value was
543 * an exact tie). We should not round up, following
544 * the HALF_DOWN rounding rule.
545 */
546 return false;
547 else
548 // Value was above the tie, we must round up.
549 return true;
550 }
551
552 // We must round up if it gives a non null digit after '5'.
553 for (int i=maximumDigits+1; i<count; ++i) {
554 if (digits[i] != '0') {
555 return true;
556 }
557 }
558 }
559 break;
560 case HALF_EVEN:
561 // Implement IEEE half-even rounding
562 if (digits[maximumDigits] > '5') {
563 return true;
564 } else if (digits[maximumDigits] == '5' ) {
565 if (maximumDigits == (count - 1)) {
566 // the rounding position is exactly the last index :
567 if (alreadyRounded)
568 // If FloatingDecimal rounded up (value was below tie),
569 // then we should not round up again.
570 return false;
571
572 if (!allDecimalDigits)
573 // Otherwise if the digits don't represent exact value,
574 // value was above tie and FloatingDecimal truncated
575 // digits to tie. We must round up.
576 return true;
577 else {
578 // This is an exact tie value, and FloatingDecimal
579 // provided all of the exact digits. We thus apply
580 // HALF_EVEN rounding rule.
581 return ((maximumDigits > 0) &&
582 (digits[maximumDigits-1] % 2 != 0));
583 }
584 } else {
585 // Rounds up if it gives a non null digit after '5'
586 for (int i=maximumDigits+1; i<count; ++i) {
587 if (digits[i] != '0')
588 return true;
589 }
590 }
591 }
592 break;
593 case UNNECESSARY:
594 for (int i=maximumDigits; i<count; ++i) {
595 if (digits[i] != '0') {
596 throw new ArithmeticException(
597 "Rounding needed with the rounding mode being set to RoundingMode.UNNECESSARY");
598 }
599 }
600 break;
601 default:
602 assert false;
603 }
604 }
605 return false;
606 }
607
608 /**
609 * Utility routine to set the value of the digit list from a long
610 */
611 final void set(boolean isNegative, long source) {
612 set(isNegative, source, 0);
613 }
614
615 /**
616 * Set the digit list to a representation of the given long value.
617 * @param isNegative Boolean value indicating whether the number is negative.
618 * @param source Value to be converted; must be >= 0 or ==
619 * Long.MIN_VALUE.
620 * @param maximumDigits The most digits which should be converted.
621 * If maximumDigits is lower than the number of significant digits
622 * in source, the representation will be rounded. Ignored if <= 0.
623 */
624 final void set(boolean isNegative, long source, int maximumDigits) {
625 this.isNegative = isNegative;
626
627 // This method does not expect a negative number. However,
628 // "source" can be a Long.MIN_VALUE (-9223372036854775808),
629 // if the number being formatted is a Long.MIN_VALUE. In that
630 // case, it will be formatted as -Long.MIN_VALUE, a number
631 // which is outside the legal range of a long, but which can
632 // be represented by DigitList.
633 if (source <= 0) {
634 if (source == Long.MIN_VALUE) {
635 decimalAt = count = MAX_COUNT;
636 System.arraycopy(LONG_MIN_REP, 0, digits, 0, count);
637 } else {
638 decimalAt = count = 0; // Values <= 0 format as zero
639 }
640 } else {
641 // Rewritten to improve performance. I used to call
642 // Long.toString(), which was about 4x slower than this code.
643 int left = MAX_COUNT;
644 int right;
645 while (source > 0) {
646 digits[--left] = (char)('0' + (source % 10));
647 source /= 10;
648 }
649 decimalAt = MAX_COUNT - left;
650 // Don't copy trailing zeros. We are guaranteed that there is at
651 // least one non-zero digit, so we don't have to check lower bounds.
652 for (right = MAX_COUNT - 1; digits[right] == '0'; --right)
653 ;
654 count = right - left + 1;
655 System.arraycopy(digits, left, digits, 0, count);
656 }
657 if (maximumDigits > 0) round(maximumDigits, false, true);
658 }
659
660 /**
661 * Set the digit list to a representation of the given BigDecimal value.
662 * This method supports both fixed-point and exponential notation.
663 * @param isNegative Boolean value indicating whether the number is negative.
664 * @param source Value to be converted; must not be a value <= 0.
665 * @param maximumDigits The most fractional or total digits which should
666 * be converted.
667 * @param fixedPoint If true, then maximumDigits is the maximum
668 * fractional digits to be converted. If false, total digits.
669 */
670 final void set(boolean isNegative, BigDecimal source, int maximumDigits, boolean fixedPoint) {
671 String s = source.toString();
672 extendDigits(s.length());
673
674 set(isNegative, s,
675 false, true,
676 maximumDigits, fixedPoint);
677 }
678
679 /**
680 * Set the digit list to a representation of the given BigInteger value.
681 * @param isNegative Boolean value indicating whether the number is negative.
682 * @param source Value to be converted; must be >= 0.
683 * @param maximumDigits The most digits which should be converted.
684 * If maximumDigits is lower than the number of significant digits
685 * in source, the representation will be rounded. Ignored if <= 0.
686 */
687 final void set(boolean isNegative, BigInteger source, int maximumDigits) {
688 this.isNegative = isNegative;
689 String s = source.toString();
690 int len = s.length();
691 extendDigits(len);
692 s.getChars(0, len, digits, 0);
693
694 decimalAt = len;
695 int right;
696 for (right = len - 1; right >= 0 && digits[right] == '0'; --right)
697 ;
698 count = right + 1;
699
700 if (maximumDigits > 0) {
701 round(maximumDigits, false, true);
702 }
703 }
704
705 /**
706 * equality test between two digit lists.
707 */
708 public boolean equals(Object obj) {
709 if (this == obj) // quick check
710 return true;
711 if (!(obj instanceof DigitList)) // (1) same object?
712 return false;
713 DigitList other = (DigitList) obj;
714 if (count != other.count ||
715 decimalAt != other.decimalAt)
716 return false;
717 for (int i = 0; i < count; i++)
718 if (digits[i] != other.digits[i])
719 return false;
720 return true;
721 }
722
723 /**
724 * Generates the hash code for the digit list.
725 */
726 public int hashCode() {
727 int hashcode = decimalAt;
728
729 for (int i = 0; i < count; i++) {
730 hashcode = hashcode * 37 + digits[i];
731 }
732
733 return hashcode;
734 }
735
736 /**
737 * Creates a copy of this object.
738 * @return a clone of this instance.
739 */
740 public Object clone() {
741 try {
742 DigitList other = (DigitList) super.clone();
743 char[] newDigits = new char[digits.length];
744 System.arraycopy(digits, 0, newDigits, 0, digits.length);
745 other.digits = newDigits;
746 other.tempBuffer = null;
747 return other;
748 } catch (CloneNotSupportedException e) {
749 throw new InternalError(e);
750 }
751 }
752
753 /**
754 * Returns true if this DigitList represents Long.MIN_VALUE;
755 * false, otherwise. This is required so that getLong() works.
756 */
757 private boolean isLongMIN_VALUE() {
758 if (decimalAt != count || count != MAX_COUNT) {
759 return false;
760 }
761
762 for (int i = 0; i < count; ++i) {
763 if (digits[i] != LONG_MIN_REP[i]) return false;
764 }
765
766 return true;
767 }
768
769 private static final int parseInt(char[] str, int offset, int strLen) {
770 char c;
771 boolean positive = true;
772 if ((c = str[offset]) == '-') {
773 positive = false;
774 offset++;
775 } else if (c == '+') {
776 offset++;
777 }
778
779 int value = 0;
780 while (offset < strLen) {
781 c = str[offset++];
782 if (c >= '0' && c <= '9') {
783 value = value * 10 + (c - '0');
784 } else {
785 break;
786 }
787 }
788 return positive ? value : -value;
789 }
790
791 // The digit part of -9223372036854775808L
792 private static final char[] LONG_MIN_REP = "9223372036854775808".toCharArray();
793
794 public String toString() {
795 if (isZero()) {
796 return "0";
797 }
798 StringBuffer buf = getStringBuffer();
799 buf.append("0.");
800 buf.append(digits, 0, count);
801 buf.append("x10^");
802 buf.append(decimalAt);
803 return buf.toString();
804 }
805
806 private StringBuffer tempBuffer;
807
808 private StringBuffer getStringBuffer() {
809 if (tempBuffer == null) {
810 tempBuffer = new StringBuffer(MAX_COUNT);
811 } else {
812 tempBuffer.setLength(0);
813 }
814 return tempBuffer;
815 }
816
817 private void extendDigits(int len) {
818 if (len > digits.length) {
819 digits = new char[len];
820 }
821 }
822
823 private final char[] getDataChars(int length) {
824 if (data == null || data.length < length) {
825 data = new char[length];
826 }
827 return data;
828 }
829 }