J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1994-2006 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 | package java.lang; |
| 27 | |
| 28 | import sun.misc.FloatingDecimal; |
| 29 | import sun.misc.FpUtils; |
| 30 | import sun.misc.DoubleConsts; |
| 31 | |
| 32 | /** |
| 33 | * The {@code Double} class wraps a value of the primitive type |
| 34 | * {@code double} in an object. An object of type |
| 35 | * {@code Double} contains a single field whose type is |
| 36 | * {@code double}. |
| 37 | * |
| 38 | * <p>In addition, this class provides several methods for converting a |
| 39 | * {@code double} to a {@code String} and a |
| 40 | * {@code String} to a {@code double}, as well as other |
| 41 | * constants and methods useful when dealing with a |
| 42 | * {@code double}. |
| 43 | * |
| 44 | * @author Lee Boynton |
| 45 | * @author Arthur van Hoff |
| 46 | * @author Joseph D. Darcy |
| 47 | * @since JDK1.0 |
| 48 | */ |
| 49 | public final class Double extends Number implements Comparable<Double> { |
| 50 | /** |
| 51 | * A constant holding the positive infinity of type |
| 52 | * {@code double}. It is equal to the value returned by |
| 53 | * {@code Double.longBitsToDouble(0x7ff0000000000000L)}. |
| 54 | */ |
| 55 | public static final double POSITIVE_INFINITY = 1.0 / 0.0; |
| 56 | |
| 57 | /** |
| 58 | * A constant holding the negative infinity of type |
| 59 | * {@code double}. It is equal to the value returned by |
| 60 | * {@code Double.longBitsToDouble(0xfff0000000000000L)}. |
| 61 | */ |
| 62 | public static final double NEGATIVE_INFINITY = -1.0 / 0.0; |
| 63 | |
| 64 | /** |
| 65 | * A constant holding a Not-a-Number (NaN) value of type |
| 66 | * {@code double}. It is equivalent to the value returned by |
| 67 | * {@code Double.longBitsToDouble(0x7ff8000000000000L)}. |
| 68 | */ |
| 69 | public static final double NaN = 0.0d / 0.0; |
| 70 | |
| 71 | /** |
| 72 | * A constant holding the largest positive finite value of type |
| 73 | * {@code double}, |
| 74 | * (2-2<sup>-52</sup>)·2<sup>1023</sup>. It is equal to |
| 75 | * the hexadecimal floating-point literal |
| 76 | * {@code 0x1.fffffffffffffP+1023} and also equal to |
| 77 | * {@code Double.longBitsToDouble(0x7fefffffffffffffL)}. |
| 78 | */ |
| 79 | public static final double MAX_VALUE = 0x1.fffffffffffffP+1023; // 1.7976931348623157e+308 |
| 80 | |
| 81 | /** |
| 82 | * A constant holding the smallest positive normal value of type |
| 83 | * {@code double}, 2<sup>-1022</sup>. It is equal to the |
| 84 | * hexadecimal floating-point literal {@code 0x1.0p-1022} and also |
| 85 | * equal to {@code Double.longBitsToDouble(0x0010000000000000L)}. |
| 86 | * |
| 87 | * @since 1.6 |
| 88 | */ |
| 89 | public static final double MIN_NORMAL = 0x1.0p-1022; // 2.2250738585072014E-308 |
| 90 | |
| 91 | /** |
| 92 | * A constant holding the smallest positive nonzero value of type |
| 93 | * {@code double}, 2<sup>-1074</sup>. It is equal to the |
| 94 | * hexadecimal floating-point literal |
| 95 | * {@code 0x0.0000000000001P-1022} and also equal to |
| 96 | * {@code Double.longBitsToDouble(0x1L)}. |
| 97 | */ |
| 98 | public static final double MIN_VALUE = 0x0.0000000000001P-1022; // 4.9e-324 |
| 99 | |
| 100 | /** |
| 101 | * Maximum exponent a finite {@code double} variable may have. |
| 102 | * It is equal to the value returned by |
| 103 | * {@code Math.getExponent(Double.MAX_VALUE)}. |
| 104 | * |
| 105 | * @since 1.6 |
| 106 | */ |
| 107 | public static final int MAX_EXPONENT = 1023; |
| 108 | |
| 109 | /** |
| 110 | * Minimum exponent a normalized {@code double} variable may |
| 111 | * have. It is equal to the value returned by |
| 112 | * {@code Math.getExponent(Double.MIN_NORMAL)}. |
| 113 | * |
| 114 | * @since 1.6 |
| 115 | */ |
| 116 | public static final int MIN_EXPONENT = -1022; |
| 117 | |
| 118 | /** |
| 119 | * The number of bits used to represent a {@code double} value. |
| 120 | * |
| 121 | * @since 1.5 |
| 122 | */ |
| 123 | public static final int SIZE = 64; |
| 124 | |
| 125 | /** |
| 126 | * The {@code Class} instance representing the primitive type |
| 127 | * {@code double}. |
| 128 | * |
| 129 | * @since JDK1.1 |
| 130 | */ |
| 131 | public static final Class<Double> TYPE = (Class<Double>) Class.getPrimitiveClass("double"); |
| 132 | |
| 133 | /** |
| 134 | * Returns a string representation of the {@code double} |
| 135 | * argument. All characters mentioned below are ASCII characters. |
| 136 | * <ul> |
| 137 | * <li>If the argument is NaN, the result is the string |
| 138 | * "{@code NaN}". |
| 139 | * <li>Otherwise, the result is a string that represents the sign and |
| 140 | * magnitude (absolute value) of the argument. If the sign is negative, |
| 141 | * the first character of the result is '{@code -}' |
| 142 | * (<code>'\u002D'</code>); if the sign is positive, no sign character |
| 143 | * appears in the result. As for the magnitude <i>m</i>: |
| 144 | * <ul> |
| 145 | * <li>If <i>m</i> is infinity, it is represented by the characters |
| 146 | * {@code "Infinity"}; thus, positive infinity produces the result |
| 147 | * {@code "Infinity"} and negative infinity produces the result |
| 148 | * {@code "-Infinity"}. |
| 149 | * |
| 150 | * <li>If <i>m</i> is zero, it is represented by the characters |
| 151 | * {@code "0.0"}; thus, negative zero produces the result |
| 152 | * {@code "-0.0"} and positive zero produces the result |
| 153 | * {@code "0.0"}. |
| 154 | * |
| 155 | * <li>If <i>m</i> is greater than or equal to 10<sup>-3</sup> but less |
| 156 | * than 10<sup>7</sup>, then it is represented as the integer part of |
| 157 | * <i>m</i>, in decimal form with no leading zeroes, followed by |
| 158 | * '{@code .}' (<code>'\u002E'</code>), followed by one or |
| 159 | * more decimal digits representing the fractional part of <i>m</i>. |
| 160 | * |
| 161 | * <li>If <i>m</i> is less than 10<sup>-3</sup> or greater than or |
| 162 | * equal to 10<sup>7</sup>, then it is represented in so-called |
| 163 | * "computerized scientific notation." Let <i>n</i> be the unique |
| 164 | * integer such that 10<sup><i>n</i></sup> ≤ <i>m</i> {@literal <} |
| 165 | * 10<sup><i>n</i>+1</sup>; then let <i>a</i> be the |
| 166 | * mathematically exact quotient of <i>m</i> and |
| 167 | * 10<sup><i>n</i></sup> so that 1 ≤ <i>a</i> {@literal <} 10. The |
| 168 | * magnitude is then represented as the integer part of <i>a</i>, |
| 169 | * as a single decimal digit, followed by '{@code .}' |
| 170 | * (<code>'\u002E'</code>), followed by decimal digits |
| 171 | * representing the fractional part of <i>a</i>, followed by the |
| 172 | * letter '{@code E}' (<code>'\u0045'</code>), followed |
| 173 | * by a representation of <i>n</i> as a decimal integer, as |
| 174 | * produced by the method {@link Integer#toString(int)}. |
| 175 | * </ul> |
| 176 | * </ul> |
| 177 | * How many digits must be printed for the fractional part of |
| 178 | * <i>m</i> or <i>a</i>? There must be at least one digit to represent |
| 179 | * the fractional part, and beyond that as many, but only as many, more |
| 180 | * digits as are needed to uniquely distinguish the argument value from |
| 181 | * adjacent values of type {@code double}. That is, suppose that |
| 182 | * <i>x</i> is the exact mathematical value represented by the decimal |
| 183 | * representation produced by this method for a finite nonzero argument |
| 184 | * <i>d</i>. Then <i>d</i> must be the {@code double} value nearest |
| 185 | * to <i>x</i>; or if two {@code double} values are equally close |
| 186 | * to <i>x</i>, then <i>d</i> must be one of them and the least |
| 187 | * significant bit of the significand of <i>d</i> must be {@code 0}. |
| 188 | * |
| 189 | * <p>To create localized string representations of a floating-point |
| 190 | * value, use subclasses of {@link java.text.NumberFormat}. |
| 191 | * |
| 192 | * @param d the {@code double} to be converted. |
| 193 | * @return a string representation of the argument. |
| 194 | */ |
| 195 | public static String toString(double d) { |
| 196 | return new FloatingDecimal(d).toJavaFormatString(); |
| 197 | } |
| 198 | |
| 199 | /** |
| 200 | * Returns a hexadecimal string representation of the |
| 201 | * {@code double} argument. All characters mentioned below |
| 202 | * are ASCII characters. |
| 203 | * |
| 204 | * <ul> |
| 205 | * <li>If the argument is NaN, the result is the string |
| 206 | * "{@code NaN}". |
| 207 | * <li>Otherwise, the result is a string that represents the sign |
| 208 | * and magnitude of the argument. If the sign is negative, the |
| 209 | * first character of the result is '{@code -}' |
| 210 | * (<code>'\u002D'</code>); if the sign is positive, no sign |
| 211 | * character appears in the result. As for the magnitude <i>m</i>: |
| 212 | * |
| 213 | * <ul> |
| 214 | * <li>If <i>m</i> is infinity, it is represented by the string |
| 215 | * {@code "Infinity"}; thus, positive infinity produces the |
| 216 | * result {@code "Infinity"} and negative infinity produces |
| 217 | * the result {@code "-Infinity"}. |
| 218 | * |
| 219 | * <li>If <i>m</i> is zero, it is represented by the string |
| 220 | * {@code "0x0.0p0"}; thus, negative zero produces the result |
| 221 | * {@code "-0x0.0p0"} and positive zero produces the result |
| 222 | * {@code "0x0.0p0"}. |
| 223 | * |
| 224 | * <li>If <i>m</i> is a {@code double} value with a |
| 225 | * normalized representation, substrings are used to represent the |
| 226 | * significand and exponent fields. The significand is |
| 227 | * represented by the characters {@code "0x1."} |
| 228 | * followed by a lowercase hexadecimal representation of the rest |
| 229 | * of the significand as a fraction. Trailing zeros in the |
| 230 | * hexadecimal representation are removed unless all the digits |
| 231 | * are zero, in which case a single zero is used. Next, the |
| 232 | * exponent is represented by {@code "p"} followed |
| 233 | * by a decimal string of the unbiased exponent as if produced by |
| 234 | * a call to {@link Integer#toString(int) Integer.toString} on the |
| 235 | * exponent value. |
| 236 | * |
| 237 | * <li>If <i>m</i> is a {@code double} value with a subnormal |
| 238 | * representation, the significand is represented by the |
| 239 | * characters {@code "0x0."} followed by a |
| 240 | * hexadecimal representation of the rest of the significand as a |
| 241 | * fraction. Trailing zeros in the hexadecimal representation are |
| 242 | * removed. Next, the exponent is represented by |
| 243 | * {@code "p-1022"}. Note that there must be at |
| 244 | * least one nonzero digit in a subnormal significand. |
| 245 | * |
| 246 | * </ul> |
| 247 | * |
| 248 | * </ul> |
| 249 | * |
| 250 | * <table border> |
| 251 | * <caption><h3>Examples</h3></caption> |
| 252 | * <tr><th>Floating-point Value</th><th>Hexadecimal String</th> |
| 253 | * <tr><td>{@code 1.0}</td> <td>{@code 0x1.0p0}</td> |
| 254 | * <tr><td>{@code -1.0}</td> <td>{@code -0x1.0p0}</td> |
| 255 | * <tr><td>{@code 2.0}</td> <td>{@code 0x1.0p1}</td> |
| 256 | * <tr><td>{@code 3.0}</td> <td>{@code 0x1.8p1}</td> |
| 257 | * <tr><td>{@code 0.5}</td> <td>{@code 0x1.0p-1}</td> |
| 258 | * <tr><td>{@code 0.25}</td> <td>{@code 0x1.0p-2}</td> |
| 259 | * <tr><td>{@code Double.MAX_VALUE}</td> |
| 260 | * <td>{@code 0x1.fffffffffffffp1023}</td> |
| 261 | * <tr><td>{@code Minimum Normal Value}</td> |
| 262 | * <td>{@code 0x1.0p-1022}</td> |
| 263 | * <tr><td>{@code Maximum Subnormal Value}</td> |
| 264 | * <td>{@code 0x0.fffffffffffffp-1022}</td> |
| 265 | * <tr><td>{@code Double.MIN_VALUE}</td> |
| 266 | * <td>{@code 0x0.0000000000001p-1022}</td> |
| 267 | * </table> |
| 268 | * @param d the {@code double} to be converted. |
| 269 | * @return a hex string representation of the argument. |
| 270 | * @since 1.5 |
| 271 | * @author Joseph D. Darcy |
| 272 | */ |
| 273 | public static String toHexString(double d) { |
| 274 | /* |
| 275 | * Modeled after the "a" conversion specifier in C99, section |
| 276 | * 7.19.6.1; however, the output of this method is more |
| 277 | * tightly specified. |
| 278 | */ |
| 279 | if (!FpUtils.isFinite(d) ) |
| 280 | // For infinity and NaN, use the decimal output. |
| 281 | return Double.toString(d); |
| 282 | else { |
| 283 | // Initialized to maximum size of output. |
| 284 | StringBuffer answer = new StringBuffer(24); |
| 285 | |
| 286 | if (FpUtils.rawCopySign(1.0, d) == -1.0) // value is negative, |
| 287 | answer.append("-"); // so append sign info |
| 288 | |
| 289 | answer.append("0x"); |
| 290 | |
| 291 | d = Math.abs(d); |
| 292 | |
| 293 | if(d == 0.0) { |
| 294 | answer.append("0.0p0"); |
| 295 | } |
| 296 | else { |
| 297 | boolean subnormal = (d < DoubleConsts.MIN_NORMAL); |
| 298 | |
| 299 | // Isolate significand bits and OR in a high-order bit |
| 300 | // so that the string representation has a known |
| 301 | // length. |
| 302 | long signifBits = (Double.doubleToLongBits(d) |
| 303 | & DoubleConsts.SIGNIF_BIT_MASK) | |
| 304 | 0x1000000000000000L; |
| 305 | |
| 306 | // Subnormal values have a 0 implicit bit; normal |
| 307 | // values have a 1 implicit bit. |
| 308 | answer.append(subnormal ? "0." : "1."); |
| 309 | |
| 310 | // Isolate the low-order 13 digits of the hex |
| 311 | // representation. If all the digits are zero, |
| 312 | // replace with a single 0; otherwise, remove all |
| 313 | // trailing zeros. |
| 314 | String signif = Long.toHexString(signifBits).substring(3,16); |
| 315 | answer.append(signif.equals("0000000000000") ? // 13 zeros |
| 316 | "0": |
| 317 | signif.replaceFirst("0{1,12}$", "")); |
| 318 | |
| 319 | // If the value is subnormal, use the E_min exponent |
| 320 | // value for double; otherwise, extract and report d's |
| 321 | // exponent (the representation of a subnormal uses |
| 322 | // E_min -1). |
| 323 | answer.append("p" + (subnormal ? |
| 324 | DoubleConsts.MIN_EXPONENT: |
| 325 | FpUtils.getExponent(d) )); |
| 326 | } |
| 327 | return answer.toString(); |
| 328 | } |
| 329 | } |
| 330 | |
| 331 | /** |
| 332 | * Returns a {@code Double} object holding the |
| 333 | * {@code double} value represented by the argument string |
| 334 | * {@code s}. |
| 335 | * |
| 336 | * <p>If {@code s} is {@code null}, then a |
| 337 | * {@code NullPointerException} is thrown. |
| 338 | * |
| 339 | * <p>Leading and trailing whitespace characters in {@code s} |
| 340 | * are ignored. Whitespace is removed as if by the {@link |
| 341 | * String#trim} method; that is, both ASCII space and control |
| 342 | * characters are removed. The rest of {@code s} should |
| 343 | * constitute a <i>FloatValue</i> as described by the lexical |
| 344 | * syntax rules: |
| 345 | * |
| 346 | * <blockquote> |
| 347 | * <dl> |
| 348 | * <dt><i>FloatValue:</i> |
| 349 | * <dd><i>Sign<sub>opt</sub></i> {@code NaN} |
| 350 | * <dd><i>Sign<sub>opt</sub></i> {@code Infinity} |
| 351 | * <dd><i>Sign<sub>opt</sub> FloatingPointLiteral</i> |
| 352 | * <dd><i>Sign<sub>opt</sub> HexFloatingPointLiteral</i> |
| 353 | * <dd><i>SignedInteger</i> |
| 354 | * </dl> |
| 355 | * |
| 356 | * <p> |
| 357 | * |
| 358 | * <dl> |
| 359 | * <dt><i>HexFloatingPointLiteral</i>: |
| 360 | * <dd> <i>HexSignificand BinaryExponent FloatTypeSuffix<sub>opt</sub></i> |
| 361 | * </dl> |
| 362 | * |
| 363 | * <p> |
| 364 | * |
| 365 | * <dl> |
| 366 | * <dt><i>HexSignificand:</i> |
| 367 | * <dd><i>HexNumeral</i> |
| 368 | * <dd><i>HexNumeral</i> {@code .} |
| 369 | * <dd>{@code 0x} <i>HexDigits<sub>opt</sub> |
| 370 | * </i>{@code .}<i> HexDigits</i> |
| 371 | * <dd>{@code 0X}<i> HexDigits<sub>opt</sub> |
| 372 | * </i>{@code .} <i>HexDigits</i> |
| 373 | * </dl> |
| 374 | * |
| 375 | * <p> |
| 376 | * |
| 377 | * <dl> |
| 378 | * <dt><i>BinaryExponent:</i> |
| 379 | * <dd><i>BinaryExponentIndicator SignedInteger</i> |
| 380 | * </dl> |
| 381 | * |
| 382 | * <p> |
| 383 | * |
| 384 | * <dl> |
| 385 | * <dt><i>BinaryExponentIndicator:</i> |
| 386 | * <dd>{@code p} |
| 387 | * <dd>{@code P} |
| 388 | * </dl> |
| 389 | * |
| 390 | * </blockquote> |
| 391 | * |
| 392 | * where <i>Sign</i>, <i>FloatingPointLiteral</i>, |
| 393 | * <i>HexNumeral</i>, <i>HexDigits</i>, <i>SignedInteger</i> and |
| 394 | * <i>FloatTypeSuffix</i> are as defined in the lexical structure |
| 395 | * sections of the <a |
| 396 | * href="http://java.sun.com/docs/books/jls/html/">Java Language |
| 397 | * Specification</a>. If {@code s} does not have the form of |
| 398 | * a <i>FloatValue</i>, then a {@code NumberFormatException} |
| 399 | * is thrown. Otherwise, {@code s} is regarded as |
| 400 | * representing an exact decimal value in the usual |
| 401 | * "computerized scientific notation" or as an exact |
| 402 | * hexadecimal value; this exact numerical value is then |
| 403 | * conceptually converted to an "infinitely precise" |
| 404 | * binary value that is then rounded to type {@code double} |
| 405 | * by the usual round-to-nearest rule of IEEE 754 floating-point |
| 406 | * arithmetic, which includes preserving the sign of a zero |
| 407 | * value. Finally, a {@code Double} object representing this |
| 408 | * {@code double} value is returned. |
| 409 | * |
| 410 | * <p> To interpret localized string representations of a |
| 411 | * floating-point value, use subclasses of {@link |
| 412 | * java.text.NumberFormat}. |
| 413 | * |
| 414 | * <p>Note that trailing format specifiers, specifiers that |
| 415 | * determine the type of a floating-point literal |
| 416 | * ({@code 1.0f} is a {@code float} value; |
| 417 | * {@code 1.0d} is a {@code double} value), do |
| 418 | * <em>not</em> influence the results of this method. In other |
| 419 | * words, the numerical value of the input string is converted |
| 420 | * directly to the target floating-point type. The two-step |
| 421 | * sequence of conversions, string to {@code float} followed |
| 422 | * by {@code float} to {@code double}, is <em>not</em> |
| 423 | * equivalent to converting a string directly to |
| 424 | * {@code double}. For example, the {@code float} |
| 425 | * literal {@code 0.1f} is equal to the {@code double} |
| 426 | * value {@code 0.10000000149011612}; the {@code float} |
| 427 | * literal {@code 0.1f} represents a different numerical |
| 428 | * value than the {@code double} literal |
| 429 | * {@code 0.1}. (The numerical value 0.1 cannot be exactly |
| 430 | * represented in a binary floating-point number.) |
| 431 | * |
| 432 | * <p>To avoid calling this method on an invalid string and having |
| 433 | * a {@code NumberFormatException} be thrown, the regular |
| 434 | * expression below can be used to screen the input string: |
| 435 | * |
| 436 | * <code> |
| 437 | * <pre> |
| 438 | * final String Digits = "(\\p{Digit}+)"; |
| 439 | * final String HexDigits = "(\\p{XDigit}+)"; |
| 440 | * // an exponent is 'e' or 'E' followed by an optionally |
| 441 | * // signed decimal integer. |
| 442 | * final String Exp = "[eE][+-]?"+Digits; |
| 443 | * final String fpRegex = |
| 444 | * ("[\\x00-\\x20]*"+ // Optional leading "whitespace" |
| 445 | * "[+-]?(" + // Optional sign character |
| 446 | * "NaN|" + // "NaN" string |
| 447 | * "Infinity|" + // "Infinity" string |
| 448 | * |
| 449 | * // A decimal floating-point string representing a finite positive |
| 450 | * // number without a leading sign has at most five basic pieces: |
| 451 | * // Digits . Digits ExponentPart FloatTypeSuffix |
| 452 | * // |
| 453 | * // Since this method allows integer-only strings as input |
| 454 | * // in addition to strings of floating-point literals, the |
| 455 | * // two sub-patterns below are simplifications of the grammar |
| 456 | * // productions from the Java Language Specification, 2nd |
| 457 | * // edition, section 3.10.2. |
| 458 | * |
| 459 | * // Digits ._opt Digits_opt ExponentPart_opt FloatTypeSuffix_opt |
| 460 | * "((("+Digits+"(\\.)?("+Digits+"?)("+Exp+")?)|"+ |
| 461 | * |
| 462 | * // . Digits ExponentPart_opt FloatTypeSuffix_opt |
| 463 | * "(\\.("+Digits+")("+Exp+")?)|"+ |
| 464 | * |
| 465 | * // Hexadecimal strings |
| 466 | * "((" + |
| 467 | * // 0[xX] HexDigits ._opt BinaryExponent FloatTypeSuffix_opt |
| 468 | * "(0[xX]" + HexDigits + "(\\.)?)|" + |
| 469 | * |
| 470 | * // 0[xX] HexDigits_opt . HexDigits BinaryExponent FloatTypeSuffix_opt |
| 471 | * "(0[xX]" + HexDigits + "?(\\.)" + HexDigits + ")" + |
| 472 | * |
| 473 | * ")[pP][+-]?" + Digits + "))" + |
| 474 | * "[fFdD]?))" + |
| 475 | * "[\\x00-\\x20]*");// Optional trailing "whitespace" |
| 476 | * |
| 477 | * if (Pattern.matches(fpRegex, myString)) |
| 478 | * Double.valueOf(myString); // Will not throw NumberFormatException |
| 479 | * else { |
| 480 | * // Perform suitable alternative action |
| 481 | * } |
| 482 | * </pre> |
| 483 | * </code> |
| 484 | * |
| 485 | * @param s the string to be parsed. |
| 486 | * @return a {@code Double} object holding the value |
| 487 | * represented by the {@code String} argument. |
| 488 | * @throws NumberFormatException if the string does not contain a |
| 489 | * parsable number. |
| 490 | */ |
| 491 | public static Double valueOf(String s) throws NumberFormatException { |
| 492 | return new Double(FloatingDecimal.readJavaFormatString(s).doubleValue()); |
| 493 | } |
| 494 | |
| 495 | /** |
| 496 | * Returns a {@code Double} instance representing the specified |
| 497 | * {@code double} value. |
| 498 | * If a new {@code Double} instance is not required, this method |
| 499 | * should generally be used in preference to the constructor |
| 500 | * {@link #Double(double)}, as this method is likely to yield |
| 501 | * significantly better space and time performance by caching |
| 502 | * frequently requested values. |
| 503 | * |
| 504 | * @param d a double value. |
| 505 | * @return a {@code Double} instance representing {@code d}. |
| 506 | * @since 1.5 |
| 507 | */ |
| 508 | public static Double valueOf(double d) { |
| 509 | return new Double(d); |
| 510 | } |
| 511 | |
| 512 | /** |
| 513 | * Returns a new {@code double} initialized to the value |
| 514 | * represented by the specified {@code String}, as performed |
| 515 | * by the {@code valueOf} method of class |
| 516 | * {@code Double}. |
| 517 | * |
| 518 | * @param s the string to be parsed. |
| 519 | * @return the {@code double} value represented by the string |
| 520 | * argument. |
| 521 | * @throws NumberFormatException if the string does not contain |
| 522 | * a parsable {@code double}. |
| 523 | * @see java.lang.Double#valueOf(String) |
| 524 | * @since 1.2 |
| 525 | */ |
| 526 | public static double parseDouble(String s) throws NumberFormatException { |
| 527 | return FloatingDecimal.readJavaFormatString(s).doubleValue(); |
| 528 | } |
| 529 | |
| 530 | /** |
| 531 | * Returns {@code true} if the specified number is a |
| 532 | * Not-a-Number (NaN) value, {@code false} otherwise. |
| 533 | * |
| 534 | * @param v the value to be tested. |
| 535 | * @return {@code true} if the value of the argument is NaN; |
| 536 | * {@code false} otherwise. |
| 537 | */ |
| 538 | static public boolean isNaN(double v) { |
| 539 | return (v != v); |
| 540 | } |
| 541 | |
| 542 | /** |
| 543 | * Returns {@code true} if the specified number is infinitely |
| 544 | * large in magnitude, {@code false} otherwise. |
| 545 | * |
| 546 | * @param v the value to be tested. |
| 547 | * @return {@code true} if the value of the argument is positive |
| 548 | * infinity or negative infinity; {@code false} otherwise. |
| 549 | */ |
| 550 | static public boolean isInfinite(double v) { |
| 551 | return (v == POSITIVE_INFINITY) || (v == NEGATIVE_INFINITY); |
| 552 | } |
| 553 | |
| 554 | /** |
| 555 | * The value of the Double. |
| 556 | * |
| 557 | * @serial |
| 558 | */ |
| 559 | private final double value; |
| 560 | |
| 561 | /** |
| 562 | * Constructs a newly allocated {@code Double} object that |
| 563 | * represents the primitive {@code double} argument. |
| 564 | * |
| 565 | * @param value the value to be represented by the {@code Double}. |
| 566 | */ |
| 567 | public Double(double value) { |
| 568 | this.value = value; |
| 569 | } |
| 570 | |
| 571 | /** |
| 572 | * Constructs a newly allocated {@code Double} object that |
| 573 | * represents the floating-point value of type {@code double} |
| 574 | * represented by the string. The string is converted to a |
| 575 | * {@code double} value as if by the {@code valueOf} method. |
| 576 | * |
| 577 | * @param s a string to be converted to a {@code Double}. |
| 578 | * @throws NumberFormatException if the string does not contain a |
| 579 | * parsable number. |
| 580 | * @see java.lang.Double#valueOf(java.lang.String) |
| 581 | */ |
| 582 | public Double(String s) throws NumberFormatException { |
| 583 | // REMIND: this is inefficient |
| 584 | this(valueOf(s).doubleValue()); |
| 585 | } |
| 586 | |
| 587 | /** |
| 588 | * Returns {@code true} if this {@code Double} value is |
| 589 | * a Not-a-Number (NaN), {@code false} otherwise. |
| 590 | * |
| 591 | * @return {@code true} if the value represented by this object is |
| 592 | * NaN; {@code false} otherwise. |
| 593 | */ |
| 594 | public boolean isNaN() { |
| 595 | return isNaN(value); |
| 596 | } |
| 597 | |
| 598 | /** |
| 599 | * Returns {@code true} if this {@code Double} value is |
| 600 | * infinitely large in magnitude, {@code false} otherwise. |
| 601 | * |
| 602 | * @return {@code true} if the value represented by this object is |
| 603 | * positive infinity or negative infinity; |
| 604 | * {@code false} otherwise. |
| 605 | */ |
| 606 | public boolean isInfinite() { |
| 607 | return isInfinite(value); |
| 608 | } |
| 609 | |
| 610 | /** |
| 611 | * Returns a string representation of this {@code Double} object. |
| 612 | * The primitive {@code double} value represented by this |
| 613 | * object is converted to a string exactly as if by the method |
| 614 | * {@code toString} of one argument. |
| 615 | * |
| 616 | * @return a {@code String} representation of this object. |
| 617 | * @see java.lang.Double#toString(double) |
| 618 | */ |
| 619 | public String toString() { |
| 620 | return String.valueOf(value); |
| 621 | } |
| 622 | |
| 623 | /** |
| 624 | * Returns the value of this {@code Double} as a {@code byte} (by |
| 625 | * casting to a {@code byte}). |
| 626 | * |
| 627 | * @return the {@code double} value represented by this object |
| 628 | * converted to type {@code byte} |
| 629 | * @since JDK1.1 |
| 630 | */ |
| 631 | public byte byteValue() { |
| 632 | return (byte)value; |
| 633 | } |
| 634 | |
| 635 | /** |
| 636 | * Returns the value of this {@code Double} as a |
| 637 | * {@code short} (by casting to a {@code short}). |
| 638 | * |
| 639 | * @return the {@code double} value represented by this object |
| 640 | * converted to type {@code short} |
| 641 | * @since JDK1.1 |
| 642 | */ |
| 643 | public short shortValue() { |
| 644 | return (short)value; |
| 645 | } |
| 646 | |
| 647 | /** |
| 648 | * Returns the value of this {@code Double} as an |
| 649 | * {@code int} (by casting to type {@code int}). |
| 650 | * |
| 651 | * @return the {@code double} value represented by this object |
| 652 | * converted to type {@code int} |
| 653 | */ |
| 654 | public int intValue() { |
| 655 | return (int)value; |
| 656 | } |
| 657 | |
| 658 | /** |
| 659 | * Returns the value of this {@code Double} as a |
| 660 | * {@code long} (by casting to type {@code long}). |
| 661 | * |
| 662 | * @return the {@code double} value represented by this object |
| 663 | * converted to type {@code long} |
| 664 | */ |
| 665 | public long longValue() { |
| 666 | return (long)value; |
| 667 | } |
| 668 | |
| 669 | /** |
| 670 | * Returns the {@code float} value of this |
| 671 | * {@code Double} object. |
| 672 | * |
| 673 | * @return the {@code double} value represented by this object |
| 674 | * converted to type {@code float} |
| 675 | * @since JDK1.0 |
| 676 | */ |
| 677 | public float floatValue() { |
| 678 | return (float)value; |
| 679 | } |
| 680 | |
| 681 | /** |
| 682 | * Returns the {@code double} value of this |
| 683 | * {@code Double} object. |
| 684 | * |
| 685 | * @return the {@code double} value represented by this object |
| 686 | */ |
| 687 | public double doubleValue() { |
| 688 | return (double)value; |
| 689 | } |
| 690 | |
| 691 | /** |
| 692 | * Returns a hash code for this {@code Double} object. The |
| 693 | * result is the exclusive OR of the two halves of the |
| 694 | * {@code long} integer bit representation, exactly as |
| 695 | * produced by the method {@link #doubleToLongBits(double)}, of |
| 696 | * the primitive {@code double} value represented by this |
| 697 | * {@code Double} object. That is, the hash code is the value |
| 698 | * of the expression: |
| 699 | * |
| 700 | * <blockquote> |
| 701 | * {@code (int)(v^(v>>>32))} |
| 702 | * </blockquote> |
| 703 | * |
| 704 | * where {@code v} is defined by: |
| 705 | * |
| 706 | * <blockquote> |
| 707 | * {@code long v = Double.doubleToLongBits(this.doubleValue());} |
| 708 | * </blockquote> |
| 709 | * |
| 710 | * @return a {@code hash code} value for this object. |
| 711 | */ |
| 712 | public int hashCode() { |
| 713 | long bits = doubleToLongBits(value); |
| 714 | return (int)(bits ^ (bits >>> 32)); |
| 715 | } |
| 716 | |
| 717 | /** |
| 718 | * Compares this object against the specified object. The result |
| 719 | * is {@code true} if and only if the argument is not |
| 720 | * {@code null} and is a {@code Double} object that |
| 721 | * represents a {@code double} that has the same value as the |
| 722 | * {@code double} represented by this object. For this |
| 723 | * purpose, two {@code double} values are considered to be |
| 724 | * the same if and only if the method {@link |
| 725 | * #doubleToLongBits(double)} returns the identical |
| 726 | * {@code long} value when applied to each. |
| 727 | * |
| 728 | * <p>Note that in most cases, for two instances of class |
| 729 | * {@code Double}, {@code d1} and {@code d2}, the |
| 730 | * value of {@code d1.equals(d2)} is {@code true} if and |
| 731 | * only if |
| 732 | * |
| 733 | * <blockquote> |
| 734 | * {@code d1.doubleValue() == d2.doubleValue()} |
| 735 | * </blockquote> |
| 736 | * |
| 737 | * <p>also has the value {@code true}. However, there are two |
| 738 | * exceptions: |
| 739 | * <ul> |
| 740 | * <li>If {@code d1} and {@code d2} both represent |
| 741 | * {@code Double.NaN}, then the {@code equals} method |
| 742 | * returns {@code true}, even though |
| 743 | * {@code Double.NaN==Double.NaN} has the value |
| 744 | * {@code false}. |
| 745 | * <li>If {@code d1} represents {@code +0.0} while |
| 746 | * {@code d2} represents {@code -0.0}, or vice versa, |
| 747 | * the {@code equal} test has the value {@code false}, |
| 748 | * even though {@code +0.0==-0.0} has the value {@code true}. |
| 749 | * </ul> |
| 750 | * This definition allows hash tables to operate properly. |
| 751 | * @param obj the object to compare with. |
| 752 | * @return {@code true} if the objects are the same; |
| 753 | * {@code false} otherwise. |
| 754 | * @see java.lang.Double#doubleToLongBits(double) |
| 755 | */ |
| 756 | public boolean equals(Object obj) { |
| 757 | return (obj instanceof Double) |
| 758 | && (doubleToLongBits(((Double)obj).value) == |
| 759 | doubleToLongBits(value)); |
| 760 | } |
| 761 | |
| 762 | /** |
| 763 | * Returns a representation of the specified floating-point value |
| 764 | * according to the IEEE 754 floating-point "double |
| 765 | * format" bit layout. |
| 766 | * |
| 767 | * <p>Bit 63 (the bit that is selected by the mask |
| 768 | * {@code 0x8000000000000000L}) represents the sign of the |
| 769 | * floating-point number. Bits |
| 770 | * 62-52 (the bits that are selected by the mask |
| 771 | * {@code 0x7ff0000000000000L}) represent the exponent. Bits 51-0 |
| 772 | * (the bits that are selected by the mask |
| 773 | * {@code 0x000fffffffffffffL}) represent the significand |
| 774 | * (sometimes called the mantissa) of the floating-point number. |
| 775 | * |
| 776 | * <p>If the argument is positive infinity, the result is |
| 777 | * {@code 0x7ff0000000000000L}. |
| 778 | * |
| 779 | * <p>If the argument is negative infinity, the result is |
| 780 | * {@code 0xfff0000000000000L}. |
| 781 | * |
| 782 | * <p>If the argument is NaN, the result is |
| 783 | * {@code 0x7ff8000000000000L}. |
| 784 | * |
| 785 | * <p>In all cases, the result is a {@code long} integer that, when |
| 786 | * given to the {@link #longBitsToDouble(long)} method, will produce a |
| 787 | * floating-point value the same as the argument to |
| 788 | * {@code doubleToLongBits} (except all NaN values are |
| 789 | * collapsed to a single "canonical" NaN value). |
| 790 | * |
| 791 | * @param value a {@code double} precision floating-point number. |
| 792 | * @return the bits that represent the floating-point number. |
| 793 | */ |
| 794 | public static long doubleToLongBits(double value) { |
| 795 | long result = doubleToRawLongBits(value); |
| 796 | // Check for NaN based on values of bit fields, maximum |
| 797 | // exponent and nonzero significand. |
| 798 | if ( ((result & DoubleConsts.EXP_BIT_MASK) == |
| 799 | DoubleConsts.EXP_BIT_MASK) && |
| 800 | (result & DoubleConsts.SIGNIF_BIT_MASK) != 0L) |
| 801 | result = 0x7ff8000000000000L; |
| 802 | return result; |
| 803 | } |
| 804 | |
| 805 | /** |
| 806 | * Returns a representation of the specified floating-point value |
| 807 | * according to the IEEE 754 floating-point "double |
| 808 | * format" bit layout, preserving Not-a-Number (NaN) values. |
| 809 | * |
| 810 | * <p>Bit 63 (the bit that is selected by the mask |
| 811 | * {@code 0x8000000000000000L}) represents the sign of the |
| 812 | * floating-point number. Bits |
| 813 | * 62-52 (the bits that are selected by the mask |
| 814 | * {@code 0x7ff0000000000000L}) represent the exponent. Bits 51-0 |
| 815 | * (the bits that are selected by the mask |
| 816 | * {@code 0x000fffffffffffffL}) represent the significand |
| 817 | * (sometimes called the mantissa) of the floating-point number. |
| 818 | * |
| 819 | * <p>If the argument is positive infinity, the result is |
| 820 | * {@code 0x7ff0000000000000L}. |
| 821 | * |
| 822 | * <p>If the argument is negative infinity, the result is |
| 823 | * {@code 0xfff0000000000000L}. |
| 824 | * |
| 825 | * <p>If the argument is NaN, the result is the {@code long} |
| 826 | * integer representing the actual NaN value. Unlike the |
| 827 | * {@code doubleToLongBits} method, |
| 828 | * {@code doubleToRawLongBits} does not collapse all the bit |
| 829 | * patterns encoding a NaN to a single "canonical" NaN |
| 830 | * value. |
| 831 | * |
| 832 | * <p>In all cases, the result is a {@code long} integer that, |
| 833 | * when given to the {@link #longBitsToDouble(long)} method, will |
| 834 | * produce a floating-point value the same as the argument to |
| 835 | * {@code doubleToRawLongBits}. |
| 836 | * |
| 837 | * @param value a {@code double} precision floating-point number. |
| 838 | * @return the bits that represent the floating-point number. |
| 839 | * @since 1.3 |
| 840 | */ |
| 841 | public static native long doubleToRawLongBits(double value); |
| 842 | |
| 843 | /** |
| 844 | * Returns the {@code double} value corresponding to a given |
| 845 | * bit representation. |
| 846 | * The argument is considered to be a representation of a |
| 847 | * floating-point value according to the IEEE 754 floating-point |
| 848 | * "double format" bit layout. |
| 849 | * |
| 850 | * <p>If the argument is {@code 0x7ff0000000000000L}, the result |
| 851 | * is positive infinity. |
| 852 | * |
| 853 | * <p>If the argument is {@code 0xfff0000000000000L}, the result |
| 854 | * is negative infinity. |
| 855 | * |
| 856 | * <p>If the argument is any value in the range |
| 857 | * {@code 0x7ff0000000000001L} through |
| 858 | * {@code 0x7fffffffffffffffL} or in the range |
| 859 | * {@code 0xfff0000000000001L} through |
| 860 | * {@code 0xffffffffffffffffL}, the result is a NaN. No IEEE |
| 861 | * 754 floating-point operation provided by Java can distinguish |
| 862 | * between two NaN values of the same type with different bit |
| 863 | * patterns. Distinct values of NaN are only distinguishable by |
| 864 | * use of the {@code Double.doubleToRawLongBits} method. |
| 865 | * |
| 866 | * <p>In all other cases, let <i>s</i>, <i>e</i>, and <i>m</i> be three |
| 867 | * values that can be computed from the argument: |
| 868 | * |
| 869 | * <blockquote><pre> |
| 870 | * int s = ((bits >> 63) == 0) ? 1 : -1; |
| 871 | * int e = (int)((bits >> 52) & 0x7ffL); |
| 872 | * long m = (e == 0) ? |
| 873 | * (bits & 0xfffffffffffffL) << 1 : |
| 874 | * (bits & 0xfffffffffffffL) | 0x10000000000000L; |
| 875 | * </pre></blockquote> |
| 876 | * |
| 877 | * Then the floating-point result equals the value of the mathematical |
| 878 | * expression <i>s</i>·<i>m</i>·2<sup><i>e</i>-1075</sup>. |
| 879 | * |
| 880 | * <p>Note that this method may not be able to return a |
| 881 | * {@code double} NaN with exactly same bit pattern as the |
| 882 | * {@code long} argument. IEEE 754 distinguishes between two |
| 883 | * kinds of NaNs, quiet NaNs and <i>signaling NaNs</i>. The |
| 884 | * differences between the two kinds of NaN are generally not |
| 885 | * visible in Java. Arithmetic operations on signaling NaNs turn |
| 886 | * them into quiet NaNs with a different, but often similar, bit |
| 887 | * pattern. However, on some processors merely copying a |
| 888 | * signaling NaN also performs that conversion. In particular, |
| 889 | * copying a signaling NaN to return it to the calling method |
| 890 | * may perform this conversion. So {@code longBitsToDouble} |
| 891 | * may not be able to return a {@code double} with a |
| 892 | * signaling NaN bit pattern. Consequently, for some |
| 893 | * {@code long} values, |
| 894 | * {@code doubleToRawLongBits(longBitsToDouble(start))} may |
| 895 | * <i>not</i> equal {@code start}. Moreover, which |
| 896 | * particular bit patterns represent signaling NaNs is platform |
| 897 | * dependent; although all NaN bit patterns, quiet or signaling, |
| 898 | * must be in the NaN range identified above. |
| 899 | * |
| 900 | * @param bits any {@code long} integer. |
| 901 | * @return the {@code double} floating-point value with the same |
| 902 | * bit pattern. |
| 903 | */ |
| 904 | public static native double longBitsToDouble(long bits); |
| 905 | |
| 906 | /** |
| 907 | * Compares two {@code Double} objects numerically. There |
| 908 | * are two ways in which comparisons performed by this method |
| 909 | * differ from those performed by the Java language numerical |
| 910 | * comparison operators ({@code <, <=, ==, >=, >}) |
| 911 | * when applied to primitive {@code double} values: |
| 912 | * <ul><li> |
| 913 | * {@code Double.NaN} is considered by this method |
| 914 | * to be equal to itself and greater than all other |
| 915 | * {@code double} values (including |
| 916 | * {@code Double.POSITIVE_INFINITY}). |
| 917 | * <li> |
| 918 | * {@code 0.0d} is considered by this method to be greater |
| 919 | * than {@code -0.0d}. |
| 920 | * </ul> |
| 921 | * This ensures that the <i>natural ordering</i> of |
| 922 | * {@code Double} objects imposed by this method is <i>consistent |
| 923 | * with equals</i>. |
| 924 | * |
| 925 | * @param anotherDouble the {@code Double} to be compared. |
| 926 | * @return the value {@code 0} if {@code anotherDouble} is |
| 927 | * numerically equal to this {@code Double}; a value |
| 928 | * less than {@code 0} if this {@code Double} |
| 929 | * is numerically less than {@code anotherDouble}; |
| 930 | * and a value greater than {@code 0} if this |
| 931 | * {@code Double} is numerically greater than |
| 932 | * {@code anotherDouble}. |
| 933 | * |
| 934 | * @since 1.2 |
| 935 | */ |
| 936 | public int compareTo(Double anotherDouble) { |
| 937 | return Double.compare(value, anotherDouble.value); |
| 938 | } |
| 939 | |
| 940 | /** |
| 941 | * Compares the two specified {@code double} values. The sign |
| 942 | * of the integer value returned is the same as that of the |
| 943 | * integer that would be returned by the call: |
| 944 | * <pre> |
| 945 | * new Double(d1).compareTo(new Double(d2)) |
| 946 | * </pre> |
| 947 | * |
| 948 | * @param d1 the first {@code double} to compare |
| 949 | * @param d2 the second {@code double} to compare |
| 950 | * @return the value {@code 0} if {@code d1} is |
| 951 | * numerically equal to {@code d2}; a value less than |
| 952 | * {@code 0} if {@code d1} is numerically less than |
| 953 | * {@code d2}; and a value greater than {@code 0} |
| 954 | * if {@code d1} is numerically greater than |
| 955 | * {@code d2}. |
| 956 | * @since 1.4 |
| 957 | */ |
| 958 | public static int compare(double d1, double d2) { |
| 959 | if (d1 < d2) |
| 960 | return -1; // Neither val is NaN, thisVal is smaller |
| 961 | if (d1 > d2) |
| 962 | return 1; // Neither val is NaN, thisVal is larger |
| 963 | |
| 964 | long thisBits = Double.doubleToLongBits(d1); |
| 965 | long anotherBits = Double.doubleToLongBits(d2); |
| 966 | |
| 967 | return (thisBits == anotherBits ? 0 : // Values are equal |
| 968 | (thisBits < anotherBits ? -1 : // (-0.0, 0.0) or (!NaN, NaN) |
| 969 | 1)); // (0.0, -0.0) or (NaN, !NaN) |
| 970 | } |
| 971 | |
| 972 | /** use serialVersionUID from JDK 1.0.2 for interoperability */ |
| 973 | private static final long serialVersionUID = -9172774392245257468L; |
| 974 | } |