J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1996-2005 Sun Microsystems, Inc. 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. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any 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.io.InvalidObjectException; |
| 42 | import java.io.IOException; |
| 43 | import java.io.ObjectInputStream; |
| 44 | import java.util.Arrays; |
| 45 | |
| 46 | /** |
| 47 | * A <code>ChoiceFormat</code> allows you to attach a format to a range of numbers. |
| 48 | * It is generally used in a <code>MessageFormat</code> for handling plurals. |
| 49 | * The choice is specified with an ascending list of doubles, where each item |
| 50 | * specifies a half-open interval up to the next item: |
| 51 | * <blockquote> |
| 52 | * <pre> |
| 53 | * X matches j if and only if limit[j] <= X < limit[j+1] |
| 54 | * </pre> |
| 55 | * </blockquote> |
| 56 | * If there is no match, then either the first or last index is used, depending |
| 57 | * on whether the number (X) is too low or too high. If the limit array is not |
| 58 | * in ascending order, the results of formatting will be incorrect. ChoiceFormat |
| 59 | * also accepts <code>\u221E</code> as equivalent to infinity(INF). |
| 60 | * |
| 61 | * <p> |
| 62 | * <strong>Note:</strong> |
| 63 | * <code>ChoiceFormat</code> differs from the other <code>Format</code> |
| 64 | * classes in that you create a <code>ChoiceFormat</code> object with a |
| 65 | * constructor (not with a <code>getInstance</code> style factory |
| 66 | * method). The factory methods aren't necessary because <code>ChoiceFormat</code> |
| 67 | * doesn't require any complex setup for a given locale. In fact, |
| 68 | * <code>ChoiceFormat</code> doesn't implement any locale specific behavior. |
| 69 | * |
| 70 | * <p> |
| 71 | * When creating a <code>ChoiceFormat</code>, you must specify an array of formats |
| 72 | * and an array of limits. The length of these arrays must be the same. |
| 73 | * For example, |
| 74 | * <ul> |
| 75 | * <li> |
| 76 | * <em>limits</em> = {1,2,3,4,5,6,7}<br> |
| 77 | * <em>formats</em> = {"Sun","Mon","Tue","Wed","Thur","Fri","Sat"} |
| 78 | * <li> |
| 79 | * <em>limits</em> = {0, 1, ChoiceFormat.nextDouble(1)}<br> |
| 80 | * <em>formats</em> = {"no files", "one file", "many files"}<br> |
| 81 | * (<code>nextDouble</code> can be used to get the next higher double, to |
| 82 | * make the half-open interval.) |
| 83 | * </ul> |
| 84 | * |
| 85 | * <p> |
| 86 | * Here is a simple example that shows formatting and parsing: |
| 87 | * <blockquote> |
| 88 | * <pre> |
| 89 | * double[] limits = {1,2,3,4,5,6,7}; |
| 90 | * String[] dayOfWeekNames = {"Sun","Mon","Tue","Wed","Thur","Fri","Sat"}; |
| 91 | * ChoiceFormat form = new ChoiceFormat(limits, dayOfWeekNames); |
| 92 | * ParsePosition status = new ParsePosition(0); |
| 93 | * for (double i = 0.0; i <= 8.0; ++i) { |
| 94 | * status.setIndex(0); |
| 95 | * System.out.println(i + " -> " + form.format(i) + " -> " |
| 96 | * + form.parse(form.format(i),status)); |
| 97 | * } |
| 98 | * </pre> |
| 99 | * </blockquote> |
| 100 | * Here is a more complex example, with a pattern format: |
| 101 | * <blockquote> |
| 102 | * <pre> |
| 103 | * double[] filelimits = {0,1,2}; |
| 104 | * String[] filepart = {"are no files","is one file","are {2} files"}; |
| 105 | * ChoiceFormat fileform = new ChoiceFormat(filelimits, filepart); |
| 106 | * Format[] testFormats = {fileform, null, NumberFormat.getInstance()}; |
| 107 | * MessageFormat pattform = new MessageFormat("There {0} on {1}"); |
| 108 | * pattform.setFormats(testFormats); |
| 109 | * Object[] testArgs = {null, "ADisk", null}; |
| 110 | * for (int i = 0; i < 4; ++i) { |
| 111 | * testArgs[0] = new Integer(i); |
| 112 | * testArgs[2] = testArgs[0]; |
| 113 | * System.out.println(pattform.format(testArgs)); |
| 114 | * } |
| 115 | * </pre> |
| 116 | * </blockquote> |
| 117 | * <p> |
| 118 | * Specifying a pattern for ChoiceFormat objects is fairly straightforward. |
| 119 | * For example: |
| 120 | * <blockquote> |
| 121 | * <pre> |
| 122 | * ChoiceFormat fmt = new ChoiceFormat( |
| 123 | * "-1#is negative| 0#is zero or fraction | 1#is one |1.0<is 1+ |2#is two |2<is more than 2."); |
| 124 | * System.out.println("Formatter Pattern : " + fmt.toPattern()); |
| 125 | * |
| 126 | * System.out.println("Format with -INF : " + fmt.format(Double.NEGATIVE_INFINITY)); |
| 127 | * System.out.println("Format with -1.0 : " + fmt.format(-1.0)); |
| 128 | * System.out.println("Format with 0 : " + fmt.format(0)); |
| 129 | * System.out.println("Format with 0.9 : " + fmt.format(0.9)); |
| 130 | * System.out.println("Format with 1.0 : " + fmt.format(1)); |
| 131 | * System.out.println("Format with 1.5 : " + fmt.format(1.5)); |
| 132 | * System.out.println("Format with 2 : " + fmt.format(2)); |
| 133 | * System.out.println("Format with 2.1 : " + fmt.format(2.1)); |
| 134 | * System.out.println("Format with NaN : " + fmt.format(Double.NaN)); |
| 135 | * System.out.println("Format with +INF : " + fmt.format(Double.POSITIVE_INFINITY)); |
| 136 | * </pre> |
| 137 | * </blockquote> |
| 138 | * And the output result would be like the following: |
| 139 | * <pre> |
| 140 | * <blockquote> |
| 141 | * Format with -INF : is negative |
| 142 | * Format with -1.0 : is negative |
| 143 | * Format with 0 : is zero or fraction |
| 144 | * Format with 0.9 : is zero or fraction |
| 145 | * Format with 1.0 : is one |
| 146 | * Format with 1.5 : is 1+ |
| 147 | * Format with 2 : is two |
| 148 | * Format with 2.1 : is more than 2. |
| 149 | * Format with NaN : is negative |
| 150 | * Format with +INF : is more than 2. |
| 151 | * </pre> |
| 152 | * </blockquote> |
| 153 | * |
| 154 | * <h4><a name="synchronization">Synchronization</a></h4> |
| 155 | * |
| 156 | * <p> |
| 157 | * Choice formats are not synchronized. |
| 158 | * It is recommended to create separate format instances for each thread. |
| 159 | * If multiple threads access a format concurrently, it must be synchronized |
| 160 | * externally. |
| 161 | * |
| 162 | * |
| 163 | * @see DecimalFormat |
| 164 | * @see MessageFormat |
| 165 | * @author Mark Davis |
| 166 | */ |
| 167 | public class ChoiceFormat extends NumberFormat { |
| 168 | |
| 169 | // Proclaim serial compatibility with 1.1 FCS |
| 170 | private static final long serialVersionUID = 1795184449645032964L; |
| 171 | |
| 172 | /** |
| 173 | * Sets the pattern. |
| 174 | * @param newPattern See the class description. |
| 175 | */ |
| 176 | public void applyPattern(String newPattern) { |
| 177 | StringBuffer[] segments = new StringBuffer[2]; |
| 178 | for (int i = 0; i < segments.length; ++i) { |
| 179 | segments[i] = new StringBuffer(); |
| 180 | } |
| 181 | double[] newChoiceLimits = new double[30]; |
| 182 | String[] newChoiceFormats = new String[30]; |
| 183 | int count = 0; |
| 184 | int part = 0; |
| 185 | double startValue = 0; |
| 186 | double oldStartValue = Double.NaN; |
| 187 | boolean inQuote = false; |
| 188 | for (int i = 0; i < newPattern.length(); ++i) { |
| 189 | char ch = newPattern.charAt(i); |
| 190 | if (ch=='\'') { |
| 191 | // Check for "''" indicating a literal quote |
| 192 | if ((i+1)<newPattern.length() && newPattern.charAt(i+1)==ch) { |
| 193 | segments[part].append(ch); |
| 194 | ++i; |
| 195 | } else { |
| 196 | inQuote = !inQuote; |
| 197 | } |
| 198 | } else if (inQuote) { |
| 199 | segments[part].append(ch); |
| 200 | } else if (ch == '<' || ch == '#' || ch == '\u2264') { |
| 201 | if (segments[0].length() == 0) { |
| 202 | throw new IllegalArgumentException(); |
| 203 | } |
| 204 | try { |
| 205 | String tempBuffer = segments[0].toString(); |
| 206 | if (tempBuffer.equals("\u221E")) { |
| 207 | startValue = Double.POSITIVE_INFINITY; |
| 208 | } else if (tempBuffer.equals("-\u221E")) { |
| 209 | startValue = Double.NEGATIVE_INFINITY; |
| 210 | } else { |
| 211 | startValue = Double.valueOf(segments[0].toString()).doubleValue(); |
| 212 | } |
| 213 | } catch (Exception e) { |
| 214 | throw new IllegalArgumentException(); |
| 215 | } |
| 216 | if (ch == '<' && startValue != Double.POSITIVE_INFINITY && |
| 217 | startValue != Double.NEGATIVE_INFINITY) { |
| 218 | startValue = nextDouble(startValue); |
| 219 | } |
| 220 | if (startValue <= oldStartValue) { |
| 221 | throw new IllegalArgumentException(); |
| 222 | } |
| 223 | segments[0].setLength(0); |
| 224 | part = 1; |
| 225 | } else if (ch == '|') { |
| 226 | if (count == newChoiceLimits.length) { |
| 227 | newChoiceLimits = doubleArraySize(newChoiceLimits); |
| 228 | newChoiceFormats = doubleArraySize(newChoiceFormats); |
| 229 | } |
| 230 | newChoiceLimits[count] = startValue; |
| 231 | newChoiceFormats[count] = segments[1].toString(); |
| 232 | ++count; |
| 233 | oldStartValue = startValue; |
| 234 | segments[1].setLength(0); |
| 235 | part = 0; |
| 236 | } else { |
| 237 | segments[part].append(ch); |
| 238 | } |
| 239 | } |
| 240 | // clean up last one |
| 241 | if (part == 1) { |
| 242 | if (count == newChoiceLimits.length) { |
| 243 | newChoiceLimits = doubleArraySize(newChoiceLimits); |
| 244 | newChoiceFormats = doubleArraySize(newChoiceFormats); |
| 245 | } |
| 246 | newChoiceLimits[count] = startValue; |
| 247 | newChoiceFormats[count] = segments[1].toString(); |
| 248 | ++count; |
| 249 | } |
| 250 | choiceLimits = new double[count]; |
| 251 | System.arraycopy(newChoiceLimits, 0, choiceLimits, 0, count); |
| 252 | choiceFormats = new String[count]; |
| 253 | System.arraycopy(newChoiceFormats, 0, choiceFormats, 0, count); |
| 254 | } |
| 255 | |
| 256 | /** |
| 257 | * Gets the pattern. |
| 258 | */ |
| 259 | public String toPattern() { |
| 260 | StringBuffer result = new StringBuffer(); |
| 261 | for (int i = 0; i < choiceLimits.length; ++i) { |
| 262 | if (i != 0) { |
| 263 | result.append('|'); |
| 264 | } |
| 265 | // choose based upon which has less precision |
| 266 | // approximate that by choosing the closest one to an integer. |
| 267 | // could do better, but it's not worth it. |
| 268 | double less = previousDouble(choiceLimits[i]); |
| 269 | double tryLessOrEqual = Math.abs(Math.IEEEremainder(choiceLimits[i], 1.0d)); |
| 270 | double tryLess = Math.abs(Math.IEEEremainder(less, 1.0d)); |
| 271 | |
| 272 | if (tryLessOrEqual < tryLess) { |
| 273 | result.append(""+choiceLimits[i]); |
| 274 | result.append('#'); |
| 275 | } else { |
| 276 | if (choiceLimits[i] == Double.POSITIVE_INFINITY) { |
| 277 | result.append("\u221E"); |
| 278 | } else if (choiceLimits[i] == Double.NEGATIVE_INFINITY) { |
| 279 | result.append("-\u221E"); |
| 280 | } else { |
| 281 | result.append(""+less); |
| 282 | } |
| 283 | result.append('<'); |
| 284 | } |
| 285 | // Append choiceFormats[i], using quotes if there are special characters. |
| 286 | // Single quotes themselves must be escaped in either case. |
| 287 | String text = choiceFormats[i]; |
| 288 | boolean needQuote = text.indexOf('<') >= 0 |
| 289 | || text.indexOf('#') >= 0 |
| 290 | || text.indexOf('\u2264') >= 0 |
| 291 | || text.indexOf('|') >= 0; |
| 292 | if (needQuote) result.append('\''); |
| 293 | if (text.indexOf('\'') < 0) result.append(text); |
| 294 | else { |
| 295 | for (int j=0; j<text.length(); ++j) { |
| 296 | char c = text.charAt(j); |
| 297 | result.append(c); |
| 298 | if (c == '\'') result.append(c); |
| 299 | } |
| 300 | } |
| 301 | if (needQuote) result.append('\''); |
| 302 | } |
| 303 | return result.toString(); |
| 304 | } |
| 305 | |
| 306 | /** |
| 307 | * Constructs with limits and corresponding formats based on the pattern. |
| 308 | * @see #applyPattern |
| 309 | */ |
| 310 | public ChoiceFormat(String newPattern) { |
| 311 | applyPattern(newPattern); |
| 312 | } |
| 313 | |
| 314 | /** |
| 315 | * Constructs with the limits and the corresponding formats. |
| 316 | * @see #setChoices |
| 317 | */ |
| 318 | public ChoiceFormat(double[] limits, String[] formats) { |
| 319 | setChoices(limits, formats); |
| 320 | } |
| 321 | |
| 322 | /** |
| 323 | * Set the choices to be used in formatting. |
| 324 | * @param limits contains the top value that you want |
| 325 | * parsed with that format,and should be in ascending sorted order. When |
| 326 | * formatting X, the choice will be the i, where |
| 327 | * limit[i] <= X < limit[i+1]. |
| 328 | * If the limit array is not in ascending order, the results of formatting |
| 329 | * will be incorrect. |
| 330 | * @param formats are the formats you want to use for each limit. |
| 331 | * They can be either Format objects or Strings. |
| 332 | * When formatting with object Y, |
| 333 | * if the object is a NumberFormat, then ((NumberFormat) Y).format(X) |
| 334 | * is called. Otherwise Y.toString() is called. |
| 335 | */ |
| 336 | public void setChoices(double[] limits, String formats[]) { |
| 337 | if (limits.length != formats.length) { |
| 338 | throw new IllegalArgumentException( |
| 339 | "Array and limit arrays must be of the same length."); |
| 340 | } |
| 341 | choiceLimits = limits; |
| 342 | choiceFormats = formats; |
| 343 | } |
| 344 | |
| 345 | /** |
| 346 | * Get the limits passed in the constructor. |
| 347 | * @return the limits. |
| 348 | */ |
| 349 | public double[] getLimits() { |
| 350 | return choiceLimits; |
| 351 | } |
| 352 | |
| 353 | /** |
| 354 | * Get the formats passed in the constructor. |
| 355 | * @return the formats. |
| 356 | */ |
| 357 | public Object[] getFormats() { |
| 358 | return choiceFormats; |
| 359 | } |
| 360 | |
| 361 | // Overrides |
| 362 | |
| 363 | /** |
| 364 | * Specialization of format. This method really calls |
| 365 | * <code>format(double, StringBuffer, FieldPosition)</code> |
| 366 | * thus the range of longs that are supported is only equal to |
| 367 | * the range that can be stored by double. This will never be |
| 368 | * a practical limitation. |
| 369 | */ |
| 370 | public StringBuffer format(long number, StringBuffer toAppendTo, |
| 371 | FieldPosition status) { |
| 372 | return format((double)number, toAppendTo, status); |
| 373 | } |
| 374 | |
| 375 | /** |
| 376 | * Returns pattern with formatted double. |
| 377 | * @param number number to be formatted & substituted. |
| 378 | * @param toAppendTo where text is appended. |
| 379 | * @param status ignore no useful status is returned. |
| 380 | */ |
| 381 | public StringBuffer format(double number, StringBuffer toAppendTo, |
| 382 | FieldPosition status) { |
| 383 | // find the number |
| 384 | int i; |
| 385 | for (i = 0; i < choiceLimits.length; ++i) { |
| 386 | if (!(number >= choiceLimits[i])) { |
| 387 | // same as number < choiceLimits, except catchs NaN |
| 388 | break; |
| 389 | } |
| 390 | } |
| 391 | --i; |
| 392 | if (i < 0) i = 0; |
| 393 | // return either a formatted number, or a string |
| 394 | return toAppendTo.append(choiceFormats[i]); |
| 395 | } |
| 396 | |
| 397 | /** |
| 398 | * Parses a Number from the input text. |
| 399 | * @param text the source text. |
| 400 | * @param status an input-output parameter. On input, the |
| 401 | * status.index field indicates the first character of the |
| 402 | * source text that should be parsed. On exit, if no error |
| 403 | * occured, status.index is set to the first unparsed character |
| 404 | * in the source text. On exit, if an error did occur, |
| 405 | * status.index is unchanged and status.errorIndex is set to the |
| 406 | * first index of the character that caused the parse to fail. |
| 407 | * @return A Number representing the value of the number parsed. |
| 408 | */ |
| 409 | public Number parse(String text, ParsePosition status) { |
| 410 | // find the best number (defined as the one with the longest parse) |
| 411 | int start = status.index; |
| 412 | int furthest = start; |
| 413 | double bestNumber = Double.NaN; |
| 414 | double tempNumber = 0.0; |
| 415 | for (int i = 0; i < choiceFormats.length; ++i) { |
| 416 | String tempString = choiceFormats[i]; |
| 417 | if (text.regionMatches(start, tempString, 0, tempString.length())) { |
| 418 | status.index = start + tempString.length(); |
| 419 | tempNumber = choiceLimits[i]; |
| 420 | if (status.index > furthest) { |
| 421 | furthest = status.index; |
| 422 | bestNumber = tempNumber; |
| 423 | if (furthest == text.length()) break; |
| 424 | } |
| 425 | } |
| 426 | } |
| 427 | status.index = furthest; |
| 428 | if (status.index == start) { |
| 429 | status.errorIndex = furthest; |
| 430 | } |
| 431 | return new Double(bestNumber); |
| 432 | } |
| 433 | |
| 434 | /** |
| 435 | * Finds the least double greater than d. |
| 436 | * If NaN, returns same value. |
| 437 | * <p>Used to make half-open intervals. |
| 438 | * @see #previousDouble |
| 439 | */ |
| 440 | public static final double nextDouble (double d) { |
| 441 | return nextDouble(d,true); |
| 442 | } |
| 443 | |
| 444 | /** |
| 445 | * Finds the greatest double less than d. |
| 446 | * If NaN, returns same value. |
| 447 | * @see #nextDouble |
| 448 | */ |
| 449 | public static final double previousDouble (double d) { |
| 450 | return nextDouble(d,false); |
| 451 | } |
| 452 | |
| 453 | /** |
| 454 | * Overrides Cloneable |
| 455 | */ |
| 456 | public Object clone() |
| 457 | { |
| 458 | ChoiceFormat other = (ChoiceFormat) super.clone(); |
| 459 | // for primitives or immutables, shallow clone is enough |
| 460 | other.choiceLimits = (double[]) choiceLimits.clone(); |
| 461 | other.choiceFormats = (String[]) choiceFormats.clone(); |
| 462 | return other; |
| 463 | } |
| 464 | |
| 465 | /** |
| 466 | * Generates a hash code for the message format object. |
| 467 | */ |
| 468 | public int hashCode() { |
| 469 | int result = choiceLimits.length; |
| 470 | if (choiceFormats.length > 0) { |
| 471 | // enough for reasonable distribution |
| 472 | result ^= choiceFormats[choiceFormats.length-1].hashCode(); |
| 473 | } |
| 474 | return result; |
| 475 | } |
| 476 | |
| 477 | /** |
| 478 | * Equality comparision between two |
| 479 | */ |
| 480 | public boolean equals(Object obj) { |
| 481 | if (obj == null) return false; |
| 482 | if (this == obj) // quick check |
| 483 | return true; |
| 484 | if (getClass() != obj.getClass()) |
| 485 | return false; |
| 486 | ChoiceFormat other = (ChoiceFormat) obj; |
| 487 | return (Arrays.equals(choiceLimits, other.choiceLimits) |
| 488 | && Arrays.equals(choiceFormats, other.choiceFormats)); |
| 489 | } |
| 490 | |
| 491 | /** |
| 492 | * After reading an object from the input stream, do a simple verification |
| 493 | * to maintain class invariants. |
| 494 | * @throws InvalidObjectException if the objects read from the stream is invalid. |
| 495 | */ |
| 496 | private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException { |
| 497 | in.defaultReadObject(); |
| 498 | if (choiceLimits.length != choiceFormats.length) { |
| 499 | throw new InvalidObjectException( |
| 500 | "limits and format arrays of different length."); |
| 501 | } |
| 502 | } |
| 503 | |
| 504 | // ===============privates=========================== |
| 505 | |
| 506 | /** |
| 507 | * A list of lower bounds for the choices. The formatter will return |
| 508 | * <code>choiceFormats[i]</code> if the number being formatted is greater than or equal to |
| 509 | * <code>choiceLimits[i]</code> and less than <code>choiceLimits[i+1]</code>. |
| 510 | * @serial |
| 511 | */ |
| 512 | private double[] choiceLimits; |
| 513 | |
| 514 | /** |
| 515 | * A list of choice strings. The formatter will return |
| 516 | * <code>choiceFormats[i]</code> if the number being formatted is greater than or equal to |
| 517 | * <code>choiceLimits[i]</code> and less than <code>choiceLimits[i+1]</code>. |
| 518 | * @serial |
| 519 | */ |
| 520 | private String[] choiceFormats; |
| 521 | |
| 522 | /* |
| 523 | static final long SIGN = 0x8000000000000000L; |
| 524 | static final long EXPONENT = 0x7FF0000000000000L; |
| 525 | static final long SIGNIFICAND = 0x000FFFFFFFFFFFFFL; |
| 526 | |
| 527 | private static double nextDouble (double d, boolean positive) { |
| 528 | if (Double.isNaN(d) || Double.isInfinite(d)) { |
| 529 | return d; |
| 530 | } |
| 531 | long bits = Double.doubleToLongBits(d); |
| 532 | long significand = bits & SIGNIFICAND; |
| 533 | if (bits < 0) { |
| 534 | significand |= (SIGN | EXPONENT); |
| 535 | } |
| 536 | long exponent = bits & EXPONENT; |
| 537 | if (positive) { |
| 538 | significand += 1; |
| 539 | // FIXME fix overflow & underflow |
| 540 | } else { |
| 541 | significand -= 1; |
| 542 | // FIXME fix overflow & underflow |
| 543 | } |
| 544 | bits = exponent | (significand & ~EXPONENT); |
| 545 | return Double.longBitsToDouble(bits); |
| 546 | } |
| 547 | */ |
| 548 | |
| 549 | static final long SIGN = 0x8000000000000000L; |
| 550 | static final long EXPONENT = 0x7FF0000000000000L; |
| 551 | static final long POSITIVEINFINITY = 0x7FF0000000000000L; |
| 552 | |
| 553 | /** |
| 554 | * Finds the least double greater than d (if positive == true), |
| 555 | * or the greatest double less than d (if positive == false). |
| 556 | * If NaN, returns same value. |
| 557 | * |
| 558 | * Does not affect floating-point flags, |
| 559 | * provided these member functions do not: |
| 560 | * Double.longBitsToDouble(long) |
| 561 | * Double.doubleToLongBits(double) |
| 562 | * Double.isNaN(double) |
| 563 | */ |
| 564 | public static double nextDouble (double d, boolean positive) { |
| 565 | |
| 566 | /* filter out NaN's */ |
| 567 | if (Double.isNaN(d)) { |
| 568 | return d; |
| 569 | } |
| 570 | |
| 571 | /* zero's are also a special case */ |
| 572 | if (d == 0.0) { |
| 573 | double smallestPositiveDouble = Double.longBitsToDouble(1L); |
| 574 | if (positive) { |
| 575 | return smallestPositiveDouble; |
| 576 | } else { |
| 577 | return -smallestPositiveDouble; |
| 578 | } |
| 579 | } |
| 580 | |
| 581 | /* if entering here, d is a nonzero value */ |
| 582 | |
| 583 | /* hold all bits in a long for later use */ |
| 584 | long bits = Double.doubleToLongBits(d); |
| 585 | |
| 586 | /* strip off the sign bit */ |
| 587 | long magnitude = bits & ~SIGN; |
| 588 | |
| 589 | /* if next double away from zero, increase magnitude */ |
| 590 | if ((bits > 0) == positive) { |
| 591 | if (magnitude != POSITIVEINFINITY) { |
| 592 | magnitude += 1; |
| 593 | } |
| 594 | } |
| 595 | /* else decrease magnitude */ |
| 596 | else { |
| 597 | magnitude -= 1; |
| 598 | } |
| 599 | |
| 600 | /* restore sign bit and return */ |
| 601 | long signbit = bits & SIGN; |
| 602 | return Double.longBitsToDouble (magnitude | signbit); |
| 603 | } |
| 604 | |
| 605 | private static double[] doubleArraySize(double[] array) { |
| 606 | int oldSize = array.length; |
| 607 | double[] newArray = new double[oldSize * 2]; |
| 608 | System.arraycopy(array, 0, newArray, 0, oldSize); |
| 609 | return newArray; |
| 610 | } |
| 611 | |
| 612 | private String[] doubleArraySize(String[] array) { |
| 613 | int oldSize = array.length; |
| 614 | String[] newArray = new String[oldSize * 2]; |
| 615 | System.arraycopy(array, 0, newArray, 0, oldSize); |
| 616 | return newArray; |
| 617 | } |
| 618 | |
| 619 | } |