J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Portions Copyright 1996-2007 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 | * Portions Copyright IBM Corporation, 2001. All Rights Reserved. |
| 28 | */ |
| 29 | |
| 30 | package java.math; |
| 31 | |
| 32 | /** |
| 33 | * Immutable, arbitrary-precision signed decimal numbers. A |
| 34 | * {@code BigDecimal} consists of an arbitrary precision integer |
| 35 | * <i>unscaled value</i> and a 32-bit integer <i>scale</i>. If zero |
| 36 | * or positive, the scale is the number of digits to the right of the |
| 37 | * decimal point. If negative, the unscaled value of the number is |
| 38 | * multiplied by ten to the power of the negation of the scale. The |
| 39 | * value of the number represented by the {@code BigDecimal} is |
| 40 | * therefore <tt>(unscaledValue × 10<sup>-scale</sup>)</tt>. |
| 41 | * |
| 42 | * <p>The {@code BigDecimal} class provides operations for |
| 43 | * arithmetic, scale manipulation, rounding, comparison, hashing, and |
| 44 | * format conversion. The {@link #toString} method provides a |
| 45 | * canonical representation of a {@code BigDecimal}. |
| 46 | * |
| 47 | * <p>The {@code BigDecimal} class gives its user complete control |
| 48 | * over rounding behavior. If no rounding mode is specified and the |
| 49 | * exact result cannot be represented, an exception is thrown; |
| 50 | * otherwise, calculations can be carried out to a chosen precision |
| 51 | * and rounding mode by supplying an appropriate {@link MathContext} |
| 52 | * object to the operation. In either case, eight <em>rounding |
| 53 | * modes</em> are provided for the control of rounding. Using the |
| 54 | * integer fields in this class (such as {@link #ROUND_HALF_UP}) to |
| 55 | * represent rounding mode is largely obsolete; the enumeration values |
| 56 | * of the {@code RoundingMode} {@code enum}, (such as {@link |
| 57 | * RoundingMode#HALF_UP}) should be used instead. |
| 58 | * |
| 59 | * <p>When a {@code MathContext} object is supplied with a precision |
| 60 | * setting of 0 (for example, {@link MathContext#UNLIMITED}), |
| 61 | * arithmetic operations are exact, as are the arithmetic methods |
| 62 | * which take no {@code MathContext} object. (This is the only |
| 63 | * behavior that was supported in releases prior to 5.) As a |
| 64 | * corollary of computing the exact result, the rounding mode setting |
| 65 | * of a {@code MathContext} object with a precision setting of 0 is |
| 66 | * not used and thus irrelevant. In the case of divide, the exact |
| 67 | * quotient could have an infinitely long decimal expansion; for |
| 68 | * example, 1 divided by 3. If the quotient has a nonterminating |
| 69 | * decimal expansion and the operation is specified to return an exact |
| 70 | * result, an {@code ArithmeticException} is thrown. Otherwise, the |
| 71 | * exact result of the division is returned, as done for other |
| 72 | * operations. |
| 73 | * |
| 74 | * <p>When the precision setting is not 0, the rules of |
| 75 | * {@code BigDecimal} arithmetic are broadly compatible with selected |
| 76 | * modes of operation of the arithmetic defined in ANSI X3.274-1996 |
| 77 | * and ANSI X3.274-1996/AM 1-2000 (section 7.4). Unlike those |
| 78 | * standards, {@code BigDecimal} includes many rounding modes, which |
| 79 | * were mandatory for division in {@code BigDecimal} releases prior |
| 80 | * to 5. Any conflicts between these ANSI standards and the |
| 81 | * {@code BigDecimal} specification are resolved in favor of |
| 82 | * {@code BigDecimal}. |
| 83 | * |
| 84 | * <p>Since the same numerical value can have different |
| 85 | * representations (with different scales), the rules of arithmetic |
| 86 | * and rounding must specify both the numerical result and the scale |
| 87 | * used in the result's representation. |
| 88 | * |
| 89 | * |
| 90 | * <p>In general the rounding modes and precision setting determine |
| 91 | * how operations return results with a limited number of digits when |
| 92 | * the exact result has more digits (perhaps infinitely many in the |
| 93 | * case of division) than the number of digits returned. |
| 94 | * |
| 95 | * First, the |
| 96 | * total number of digits to return is specified by the |
| 97 | * {@code MathContext}'s {@code precision} setting; this determines |
| 98 | * the result's <i>precision</i>. The digit count starts from the |
| 99 | * leftmost nonzero digit of the exact result. The rounding mode |
| 100 | * determines how any discarded trailing digits affect the returned |
| 101 | * result. |
| 102 | * |
| 103 | * <p>For all arithmetic operators , the operation is carried out as |
| 104 | * though an exact intermediate result were first calculated and then |
| 105 | * rounded to the number of digits specified by the precision setting |
| 106 | * (if necessary), using the selected rounding mode. If the exact |
| 107 | * result is not returned, some digit positions of the exact result |
| 108 | * are discarded. When rounding increases the magnitude of the |
| 109 | * returned result, it is possible for a new digit position to be |
| 110 | * created by a carry propagating to a leading {@literal "9"} digit. |
| 111 | * For example, rounding the value 999.9 to three digits rounding up |
| 112 | * would be numerically equal to one thousand, represented as |
| 113 | * 100×10<sup>1</sup>. In such cases, the new {@literal "1"} is |
| 114 | * the leading digit position of the returned result. |
| 115 | * |
| 116 | * <p>Besides a logical exact result, each arithmetic operation has a |
| 117 | * preferred scale for representing a result. The preferred |
| 118 | * scale for each operation is listed in the table below. |
| 119 | * |
| 120 | * <table border> |
| 121 | * <caption top><h3>Preferred Scales for Results of Arithmetic Operations |
| 122 | * </h3></caption> |
| 123 | * <tr><th>Operation</th><th>Preferred Scale of Result</th></tr> |
| 124 | * <tr><td>Add</td><td>max(addend.scale(), augend.scale())</td> |
| 125 | * <tr><td>Subtract</td><td>max(minuend.scale(), subtrahend.scale())</td> |
| 126 | * <tr><td>Multiply</td><td>multiplier.scale() + multiplicand.scale()</td> |
| 127 | * <tr><td>Divide</td><td>dividend.scale() - divisor.scale()</td> |
| 128 | * </table> |
| 129 | * |
| 130 | * These scales are the ones used by the methods which return exact |
| 131 | * arithmetic results; except that an exact divide may have to use a |
| 132 | * larger scale since the exact result may have more digits. For |
| 133 | * example, {@code 1/32} is {@code 0.03125}. |
| 134 | * |
| 135 | * <p>Before rounding, the scale of the logical exact intermediate |
| 136 | * result is the preferred scale for that operation. If the exact |
| 137 | * numerical result cannot be represented in {@code precision} |
| 138 | * digits, rounding selects the set of digits to return and the scale |
| 139 | * of the result is reduced from the scale of the intermediate result |
| 140 | * to the least scale which can represent the {@code precision} |
| 141 | * digits actually returned. If the exact result can be represented |
| 142 | * with at most {@code precision} digits, the representation |
| 143 | * of the result with the scale closest to the preferred scale is |
| 144 | * returned. In particular, an exactly representable quotient may be |
| 145 | * represented in fewer than {@code precision} digits by removing |
| 146 | * trailing zeros and decreasing the scale. For example, rounding to |
| 147 | * three digits using the {@linkplain RoundingMode#FLOOR floor} |
| 148 | * rounding mode, <br> |
| 149 | * |
| 150 | * {@code 19/100 = 0.19 // integer=19, scale=2} <br> |
| 151 | * |
| 152 | * but<br> |
| 153 | * |
| 154 | * {@code 21/110 = 0.190 // integer=190, scale=3} <br> |
| 155 | * |
| 156 | * <p>Note that for add, subtract, and multiply, the reduction in |
| 157 | * scale will equal the number of digit positions of the exact result |
| 158 | * which are discarded. If the rounding causes a carry propagation to |
| 159 | * create a new high-order digit position, an additional digit of the |
| 160 | * result is discarded than when no new digit position is created. |
| 161 | * |
| 162 | * <p>Other methods may have slightly different rounding semantics. |
| 163 | * For example, the result of the {@code pow} method using the |
| 164 | * {@linkplain #pow(int, MathContext) specified algorithm} can |
| 165 | * occasionally differ from the rounded mathematical result by more |
| 166 | * than one unit in the last place, one <i>{@linkplain #ulp() ulp}</i>. |
| 167 | * |
| 168 | * <p>Two types of operations are provided for manipulating the scale |
| 169 | * of a {@code BigDecimal}: scaling/rounding operations and decimal |
| 170 | * point motion operations. Scaling/rounding operations ({@link |
| 171 | * #setScale setScale} and {@link #round round}) return a |
| 172 | * {@code BigDecimal} whose value is approximately (or exactly) equal |
| 173 | * to that of the operand, but whose scale or precision is the |
| 174 | * specified value; that is, they increase or decrease the precision |
| 175 | * of the stored number with minimal effect on its value. Decimal |
| 176 | * point motion operations ({@link #movePointLeft movePointLeft} and |
| 177 | * {@link #movePointRight movePointRight}) return a |
| 178 | * {@code BigDecimal} created from the operand by moving the decimal |
| 179 | * point a specified distance in the specified direction. |
| 180 | * |
| 181 | * <p>For the sake of brevity and clarity, pseudo-code is used |
| 182 | * throughout the descriptions of {@code BigDecimal} methods. The |
| 183 | * pseudo-code expression {@code (i + j)} is shorthand for "a |
| 184 | * {@code BigDecimal} whose value is that of the {@code BigDecimal} |
| 185 | * {@code i} added to that of the {@code BigDecimal} |
| 186 | * {@code j}." The pseudo-code expression {@code (i == j)} is |
| 187 | * shorthand for "{@code true} if and only if the |
| 188 | * {@code BigDecimal} {@code i} represents the same value as the |
| 189 | * {@code BigDecimal} {@code j}." Other pseudo-code expressions |
| 190 | * are interpreted similarly. Square brackets are used to represent |
| 191 | * the particular {@code BigInteger} and scale pair defining a |
| 192 | * {@code BigDecimal} value; for example [19, 2] is the |
| 193 | * {@code BigDecimal} numerically equal to 0.19 having a scale of 2. |
| 194 | * |
| 195 | * <p>Note: care should be exercised if {@code BigDecimal} objects |
| 196 | * are used as keys in a {@link java.util.SortedMap SortedMap} or |
| 197 | * elements in a {@link java.util.SortedSet SortedSet} since |
| 198 | * {@code BigDecimal}'s <i>natural ordering</i> is <i>inconsistent |
| 199 | * with equals</i>. See {@link Comparable}, {@link |
| 200 | * java.util.SortedMap} or {@link java.util.SortedSet} for more |
| 201 | * information. |
| 202 | * |
| 203 | * <p>All methods and constructors for this class throw |
| 204 | * {@code NullPointerException} when passed a {@code null} object |
| 205 | * reference for any input parameter. |
| 206 | * |
| 207 | * @see BigInteger |
| 208 | * @see MathContext |
| 209 | * @see RoundingMode |
| 210 | * @see java.util.SortedMap |
| 211 | * @see java.util.SortedSet |
| 212 | * @author Josh Bloch |
| 213 | * @author Mike Cowlishaw |
| 214 | * @author Joseph D. Darcy |
| 215 | */ |
| 216 | public class BigDecimal extends Number implements Comparable<BigDecimal> { |
| 217 | /** |
| 218 | * The unscaled value of this BigDecimal, as returned by {@link |
| 219 | * #unscaledValue}. |
| 220 | * |
| 221 | * @serial |
| 222 | * @see #unscaledValue |
| 223 | */ |
| 224 | private volatile BigInteger intVal; |
| 225 | |
| 226 | /** |
| 227 | * The scale of this BigDecimal, as returned by {@link #scale}. |
| 228 | * |
| 229 | * @serial |
| 230 | * @see #scale |
| 231 | */ |
| 232 | private int scale = 0; // Note: this may have any value, so |
| 233 | // calculations must be done in longs |
| 234 | /** |
| 235 | * The number of decimal digits in this BigDecimal, or 0 if the |
| 236 | * number of digits are not known (lookaside information). If |
| 237 | * nonzero, the value is guaranteed correct. Use the precision() |
| 238 | * method to obtain and set the value if it might be 0. This |
| 239 | * field is mutable until set nonzero. |
| 240 | * |
| 241 | * @since 1.5 |
| 242 | */ |
| 243 | private volatile transient int precision = 0; |
| 244 | |
| 245 | /** |
| 246 | * Used to store the canonical string representation, if computed. |
| 247 | */ |
| 248 | private volatile transient String stringCache = null; |
| 249 | |
| 250 | /** |
| 251 | * Sentinel value for {@link #intCompact} indicating the |
| 252 | * significand information is only available from {@code intVal}. |
| 253 | */ |
| 254 | private static final long INFLATED = Long.MIN_VALUE; |
| 255 | |
| 256 | /** |
| 257 | * If the absolute value of the significand of this BigDecimal is |
| 258 | * less than or equal to {@code Long.MAX_VALUE}, the value can be |
| 259 | * compactly stored in this field and used in computations. |
| 260 | */ |
| 261 | private transient long intCompact = INFLATED; |
| 262 | |
| 263 | // All 18-digit base ten strings fit into a long; not all 19-digit |
| 264 | // strings will |
| 265 | private static final int MAX_COMPACT_DIGITS = 18; |
| 266 | |
| 267 | private static final int MAX_BIGINT_BITS = 62; |
| 268 | |
| 269 | /* Appease the serialization gods */ |
| 270 | private static final long serialVersionUID = 6108874887143696463L; |
| 271 | |
| 272 | // Cache of common small BigDecimal values. |
| 273 | private static final BigDecimal zeroThroughTen[] = { |
| 274 | new BigDecimal(BigInteger.ZERO, 0, 0), |
| 275 | new BigDecimal(BigInteger.ONE, 1, 0), |
| 276 | new BigDecimal(BigInteger.valueOf(2), 2, 0), |
| 277 | new BigDecimal(BigInteger.valueOf(3), 3, 0), |
| 278 | new BigDecimal(BigInteger.valueOf(4), 4, 0), |
| 279 | new BigDecimal(BigInteger.valueOf(5), 5, 0), |
| 280 | new BigDecimal(BigInteger.valueOf(6), 6, 0), |
| 281 | new BigDecimal(BigInteger.valueOf(7), 7, 0), |
| 282 | new BigDecimal(BigInteger.valueOf(8), 8, 0), |
| 283 | new BigDecimal(BigInteger.valueOf(9), 9, 0), |
| 284 | new BigDecimal(BigInteger.TEN, 10, 0), |
| 285 | }; |
| 286 | |
| 287 | // Constants |
| 288 | /** |
| 289 | * The value 0, with a scale of 0. |
| 290 | * |
| 291 | * @since 1.5 |
| 292 | */ |
| 293 | public static final BigDecimal ZERO = |
| 294 | zeroThroughTen[0]; |
| 295 | |
| 296 | /** |
| 297 | * The value 1, with a scale of 0. |
| 298 | * |
| 299 | * @since 1.5 |
| 300 | */ |
| 301 | public static final BigDecimal ONE = |
| 302 | zeroThroughTen[1]; |
| 303 | |
| 304 | /** |
| 305 | * The value 10, with a scale of 0. |
| 306 | * |
| 307 | * @since 1.5 |
| 308 | */ |
| 309 | public static final BigDecimal TEN = |
| 310 | zeroThroughTen[10]; |
| 311 | |
| 312 | // Constructors |
| 313 | |
| 314 | /** |
| 315 | * Translates a character array representation of a |
| 316 | * {@code BigDecimal} into a {@code BigDecimal}, accepting the |
| 317 | * same sequence of characters as the {@link #BigDecimal(String)} |
| 318 | * constructor, while allowing a sub-array to be specified. |
| 319 | * |
| 320 | * <p>Note that if the sequence of characters is already available |
| 321 | * within a character array, using this constructor is faster than |
| 322 | * converting the {@code char} array to string and using the |
| 323 | * {@code BigDecimal(String)} constructor . |
| 324 | * |
| 325 | * @param in {@code char} array that is the source of characters. |
| 326 | * @param offset first character in the array to inspect. |
| 327 | * @param len number of characters to consider. |
| 328 | * @throws NumberFormatException if {@code in} is not a valid |
| 329 | * representation of a {@code BigDecimal} or the defined subarray |
| 330 | * is not wholly within {@code in}. |
| 331 | * @since 1.5 |
| 332 | */ |
| 333 | public BigDecimal(char[] in, int offset, int len) { |
| 334 | // This is the primary string to BigDecimal constructor; all |
| 335 | // incoming strings end up here; it uses explicit (inline) |
| 336 | // parsing for speed and generates at most one intermediate |
| 337 | // (temporary) object (a char[] array). |
| 338 | |
| 339 | // use array bounds checking to handle too-long, len == 0, |
| 340 | // bad offset, etc. |
| 341 | try { |
| 342 | // handle the sign |
| 343 | boolean isneg = false; // assume positive |
| 344 | if (in[offset] == '-') { |
| 345 | isneg = true; // leading minus means negative |
| 346 | offset++; |
| 347 | len--; |
| 348 | } else if (in[offset] == '+') { // leading + allowed |
| 349 | offset++; |
| 350 | len--; |
| 351 | } |
| 352 | |
| 353 | // should now be at numeric part of the significand |
| 354 | int dotoff = -1; // '.' offset, -1 if none |
| 355 | int cfirst = offset; // record start of integer |
| 356 | long exp = 0; // exponent |
| 357 | if (len > in.length) // protect against huge length |
| 358 | throw new NumberFormatException(); |
| 359 | char coeff[] = new char[len]; // integer significand array |
| 360 | char c; // work |
| 361 | |
| 362 | for (; len > 0; offset++, len--) { |
| 363 | c = in[offset]; |
| 364 | if ((c >= '0' && c <= '9') || Character.isDigit(c)) { |
| 365 | // have digit |
| 366 | coeff[precision] = c; |
| 367 | precision++; // count of digits |
| 368 | continue; |
| 369 | } |
| 370 | if (c == '.') { |
| 371 | // have dot |
| 372 | if (dotoff >= 0) // two dots |
| 373 | throw new NumberFormatException(); |
| 374 | dotoff = offset; |
| 375 | continue; |
| 376 | } |
| 377 | // exponent expected |
| 378 | if ((c != 'e') && (c != 'E')) |
| 379 | throw new NumberFormatException(); |
| 380 | offset++; |
| 381 | c = in[offset]; |
| 382 | len--; |
| 383 | boolean negexp = false; |
| 384 | // optional sign |
| 385 | if (c == '-' || c == '+') { |
| 386 | negexp = (c == '-'); |
| 387 | offset++; |
| 388 | c = in[offset]; |
| 389 | len--; |
| 390 | } |
| 391 | if (len <= 0) // no exponent digits |
| 392 | throw new NumberFormatException(); |
| 393 | // skip leading zeros in the exponent |
| 394 | while (len > 10 && Character.digit(c, 10) == 0) { |
| 395 | offset++; |
| 396 | c = in[offset]; |
| 397 | len--; |
| 398 | } |
| 399 | if (len > 10) // too many nonzero exponent digits |
| 400 | throw new NumberFormatException(); |
| 401 | // c now holds first digit of exponent |
| 402 | for (;; len--) { |
| 403 | int v; |
| 404 | if (c >= '0' && c <= '9') { |
| 405 | v = c - '0'; |
| 406 | } else { |
| 407 | v = Character.digit(c, 10); |
| 408 | if (v < 0) // not a digit |
| 409 | throw new NumberFormatException(); |
| 410 | } |
| 411 | exp = exp * 10 + v; |
| 412 | if (len == 1) |
| 413 | break; // that was final character |
| 414 | offset++; |
| 415 | c = in[offset]; |
| 416 | } |
| 417 | if (negexp) // apply sign |
| 418 | exp = -exp; |
| 419 | // Next test is required for backwards compatibility |
| 420 | if ((int)exp != exp) // overflow |
| 421 | throw new NumberFormatException(); |
| 422 | break; // [saves a test] |
| 423 | } |
| 424 | // here when no characters left |
| 425 | if (precision == 0) // no digits found |
| 426 | throw new NumberFormatException(); |
| 427 | |
| 428 | if (dotoff >= 0) { // had dot; set scale |
| 429 | scale = precision - (dotoff - cfirst); |
| 430 | // [cannot overflow] |
| 431 | } |
| 432 | if (exp != 0) { // had significant exponent |
| 433 | try { |
| 434 | scale = checkScale(-exp + scale); // adjust |
| 435 | } catch (ArithmeticException e) { |
| 436 | throw new NumberFormatException("Scale out of range."); |
| 437 | } |
| 438 | } |
| 439 | |
| 440 | // Remove leading zeros from precision (digits count) |
| 441 | int first = 0; |
| 442 | for (; (coeff[first] == '0' || Character.digit(coeff[first], 10) == 0) && |
| 443 | precision > 1; |
| 444 | first++) |
| 445 | precision--; |
| 446 | |
| 447 | // Set the significand .. |
| 448 | // Copy significand to exact-sized array, with sign if |
| 449 | // negative |
| 450 | // Later use: BigInteger(coeff, first, precision) for |
| 451 | // both cases, by allowing an extra char at the front of |
| 452 | // coeff. |
| 453 | char quick[]; |
| 454 | if (!isneg) { |
| 455 | quick = new char[precision]; |
| 456 | System.arraycopy(coeff, first, quick, 0, precision); |
| 457 | } else { |
| 458 | quick = new char[precision+1]; |
| 459 | quick[0] = '-'; |
| 460 | System.arraycopy(coeff, first, quick, 1, precision); |
| 461 | } |
| 462 | if (precision <= MAX_COMPACT_DIGITS) |
| 463 | intCompact = Long.parseLong(new String(quick)); |
| 464 | else |
| 465 | intVal = new BigInteger(quick); |
| 466 | // System.out.println(" new: " +intVal+" ["+scale+"] "+precision); |
| 467 | } catch (ArrayIndexOutOfBoundsException e) { |
| 468 | throw new NumberFormatException(); |
| 469 | } catch (NegativeArraySizeException e) { |
| 470 | throw new NumberFormatException(); |
| 471 | } |
| 472 | } |
| 473 | |
| 474 | /** |
| 475 | * Translates a character array representation of a |
| 476 | * {@code BigDecimal} into a {@code BigDecimal}, accepting the |
| 477 | * same sequence of characters as the {@link #BigDecimal(String)} |
| 478 | * constructor, while allowing a sub-array to be specified and |
| 479 | * with rounding according to the context settings. |
| 480 | * |
| 481 | * <p>Note that if the sequence of characters is already available |
| 482 | * within a character array, using this constructor is faster than |
| 483 | * converting the {@code char} array to string and using the |
| 484 | * {@code BigDecimal(String)} constructor . |
| 485 | * |
| 486 | * @param in {@code char} array that is the source of characters. |
| 487 | * @param offset first character in the array to inspect. |
| 488 | * @param len number of characters to consider.. |
| 489 | * @param mc the context to use. |
| 490 | * @throws ArithmeticException if the result is inexact but the |
| 491 | * rounding mode is {@code UNNECESSARY}. |
| 492 | * @throws NumberFormatException if {@code in} is not a valid |
| 493 | * representation of a {@code BigDecimal} or the defined subarray |
| 494 | * is not wholly within {@code in}. |
| 495 | * @since 1.5 |
| 496 | */ |
| 497 | public BigDecimal(char[] in, int offset, int len, MathContext mc) { |
| 498 | this(in, offset, len); |
| 499 | if (mc.precision > 0) |
| 500 | roundThis(mc); |
| 501 | } |
| 502 | |
| 503 | /** |
| 504 | * Translates a character array representation of a |
| 505 | * {@code BigDecimal} into a {@code BigDecimal}, accepting the |
| 506 | * same sequence of characters as the {@link #BigDecimal(String)} |
| 507 | * constructor. |
| 508 | * |
| 509 | * <p>Note that if the sequence of characters is already available |
| 510 | * as a character array, using this constructor is faster than |
| 511 | * converting the {@code char} array to string and using the |
| 512 | * {@code BigDecimal(String)} constructor . |
| 513 | * |
| 514 | * @param in {@code char} array that is the source of characters. |
| 515 | * @throws NumberFormatException if {@code in} is not a valid |
| 516 | * representation of a {@code BigDecimal}. |
| 517 | * @since 1.5 |
| 518 | */ |
| 519 | public BigDecimal(char[] in) { |
| 520 | this(in, 0, in.length); |
| 521 | } |
| 522 | |
| 523 | /** |
| 524 | * Translates a character array representation of a |
| 525 | * {@code BigDecimal} into a {@code BigDecimal}, accepting the |
| 526 | * same sequence of characters as the {@link #BigDecimal(String)} |
| 527 | * constructor and with rounding according to the context |
| 528 | * settings. |
| 529 | * |
| 530 | * <p>Note that if the sequence of characters is already available |
| 531 | * as a character array, using this constructor is faster than |
| 532 | * converting the {@code char} array to string and using the |
| 533 | * {@code BigDecimal(String)} constructor . |
| 534 | * |
| 535 | * @param in {@code char} array that is the source of characters. |
| 536 | * @param mc the context to use. |
| 537 | * @throws ArithmeticException if the result is inexact but the |
| 538 | * rounding mode is {@code UNNECESSARY}. |
| 539 | * @throws NumberFormatException if {@code in} is not a valid |
| 540 | * representation of a {@code BigDecimal}. |
| 541 | * @since 1.5 |
| 542 | */ |
| 543 | public BigDecimal(char[] in, MathContext mc) { |
| 544 | this(in, 0, in.length, mc); |
| 545 | } |
| 546 | |
| 547 | /** |
| 548 | * Translates the string representation of a {@code BigDecimal} |
| 549 | * into a {@code BigDecimal}. The string representation consists |
| 550 | * of an optional sign, {@code '+'} (<tt> '\u002B'</tt>) or |
| 551 | * {@code '-'} (<tt>'\u002D'</tt>), followed by a sequence of |
| 552 | * zero or more decimal digits ("the integer"), optionally |
| 553 | * followed by a fraction, optionally followed by an exponent. |
| 554 | * |
| 555 | * <p>The fraction consists of a decimal point followed by zero |
| 556 | * or more decimal digits. The string must contain at least one |
| 557 | * digit in either the integer or the fraction. The number formed |
| 558 | * by the sign, the integer and the fraction is referred to as the |
| 559 | * <i>significand</i>. |
| 560 | * |
| 561 | * <p>The exponent consists of the character {@code 'e'} |
| 562 | * (<tt>'\u0065'</tt>) or {@code 'E'} (<tt>'\u0045'</tt>) |
| 563 | * followed by one or more decimal digits. The value of the |
| 564 | * exponent must lie between -{@link Integer#MAX_VALUE} ({@link |
| 565 | * Integer#MIN_VALUE}+1) and {@link Integer#MAX_VALUE}, inclusive. |
| 566 | * |
| 567 | * <p>More formally, the strings this constructor accepts are |
| 568 | * described by the following grammar: |
| 569 | * <blockquote> |
| 570 | * <dl> |
| 571 | * <dt><i>BigDecimalString:</i> |
| 572 | * <dd><i>Sign<sub>opt</sub> Significand Exponent<sub>opt</sub></i> |
| 573 | * <p> |
| 574 | * <dt><i>Sign:</i> |
| 575 | * <dd>{@code +} |
| 576 | * <dd>{@code -} |
| 577 | * <p> |
| 578 | * <dt><i>Significand:</i> |
| 579 | * <dd><i>IntegerPart</i> {@code .} <i>FractionPart<sub>opt</sub></i> |
| 580 | * <dd>{@code .} <i>FractionPart</i> |
| 581 | * <dd><i>IntegerPart</i> |
| 582 | * <p> |
| 583 | * <dt><i>IntegerPart: |
| 584 | * <dd>Digits</i> |
| 585 | * <p> |
| 586 | * <dt><i>FractionPart: |
| 587 | * <dd>Digits</i> |
| 588 | * <p> |
| 589 | * <dt><i>Exponent: |
| 590 | * <dd>ExponentIndicator SignedInteger</i> |
| 591 | * <p> |
| 592 | * <dt><i>ExponentIndicator:</i> |
| 593 | * <dd>{@code e} |
| 594 | * <dd>{@code E} |
| 595 | * <p> |
| 596 | * <dt><i>SignedInteger: |
| 597 | * <dd>Sign<sub>opt</sub> Digits</i> |
| 598 | * <p> |
| 599 | * <dt><i>Digits: |
| 600 | * <dd>Digit |
| 601 | * <dd>Digits Digit</i> |
| 602 | * <p> |
| 603 | * <dt><i>Digit:</i> |
| 604 | * <dd>any character for which {@link Character#isDigit} |
| 605 | * returns {@code true}, including 0, 1, 2 ... |
| 606 | * </dl> |
| 607 | * </blockquote> |
| 608 | * |
| 609 | * <p>The scale of the returned {@code BigDecimal} will be the |
| 610 | * number of digits in the fraction, or zero if the string |
| 611 | * contains no decimal point, subject to adjustment for any |
| 612 | * exponent; if the string contains an exponent, the exponent is |
| 613 | * subtracted from the scale. The value of the resulting scale |
| 614 | * must lie between {@code Integer.MIN_VALUE} and |
| 615 | * {@code Integer.MAX_VALUE}, inclusive. |
| 616 | * |
| 617 | * <p>The character-to-digit mapping is provided by {@link |
| 618 | * java.lang.Character#digit} set to convert to radix 10. The |
| 619 | * String may not contain any extraneous characters (whitespace, |
| 620 | * for example). |
| 621 | * |
| 622 | * <p><b>Examples:</b><br> |
| 623 | * The value of the returned {@code BigDecimal} is equal to |
| 624 | * <i>significand</i> × 10<sup> <i>exponent</i></sup>. |
| 625 | * For each string on the left, the resulting representation |
| 626 | * [{@code BigInteger}, {@code scale}] is shown on the right. |
| 627 | * <pre> |
| 628 | * "0" [0,0] |
| 629 | * "0.00" [0,2] |
| 630 | * "123" [123,0] |
| 631 | * "-123" [-123,0] |
| 632 | * "1.23E3" [123,-1] |
| 633 | * "1.23E+3" [123,-1] |
| 634 | * "12.3E+7" [123,-6] |
| 635 | * "12.0" [120,1] |
| 636 | * "12.3" [123,1] |
| 637 | * "0.00123" [123,5] |
| 638 | * "-1.23E-12" [-123,14] |
| 639 | * "1234.5E-4" [12345,5] |
| 640 | * "0E+7" [0,-7] |
| 641 | * "-0" [0,0] |
| 642 | * </pre> |
| 643 | * |
| 644 | * <p>Note: For values other than {@code float} and |
| 645 | * {@code double} NaN and ±Infinity, this constructor is |
| 646 | * compatible with the values returned by {@link Float#toString} |
| 647 | * and {@link Double#toString}. This is generally the preferred |
| 648 | * way to convert a {@code float} or {@code double} into a |
| 649 | * BigDecimal, as it doesn't suffer from the unpredictability of |
| 650 | * the {@link #BigDecimal(double)} constructor. |
| 651 | * |
| 652 | * @param val String representation of {@code BigDecimal}. |
| 653 | * |
| 654 | * @throws NumberFormatException if {@code val} is not a valid |
| 655 | * representation of a {@code BigDecimal}. |
| 656 | */ |
| 657 | public BigDecimal(String val) { |
| 658 | this(val.toCharArray(), 0, val.length()); |
| 659 | } |
| 660 | |
| 661 | /** |
| 662 | * Translates the string representation of a {@code BigDecimal} |
| 663 | * into a {@code BigDecimal}, accepting the same strings as the |
| 664 | * {@link #BigDecimal(String)} constructor, with rounding |
| 665 | * according to the context settings. |
| 666 | * |
| 667 | * @param val string representation of a {@code BigDecimal}. |
| 668 | * @param mc the context to use. |
| 669 | * @throws ArithmeticException if the result is inexact but the |
| 670 | * rounding mode is {@code UNNECESSARY}. |
| 671 | * @throws NumberFormatException if {@code val} is not a valid |
| 672 | * representation of a BigDecimal. |
| 673 | * @since 1.5 |
| 674 | */ |
| 675 | public BigDecimal(String val, MathContext mc) { |
| 676 | this(val.toCharArray(), 0, val.length()); |
| 677 | if (mc.precision > 0) |
| 678 | roundThis(mc); |
| 679 | } |
| 680 | |
| 681 | /** |
| 682 | * Translates a {@code double} into a {@code BigDecimal} which |
| 683 | * is the exact decimal representation of the {@code double}'s |
| 684 | * binary floating-point value. The scale of the returned |
| 685 | * {@code BigDecimal} is the smallest value such that |
| 686 | * <tt>(10<sup>scale</sup> × val)</tt> is an integer. |
| 687 | * <p> |
| 688 | * <b>Notes:</b> |
| 689 | * <ol> |
| 690 | * <li> |
| 691 | * The results of this constructor can be somewhat unpredictable. |
| 692 | * One might assume that writing {@code new BigDecimal(0.1)} in |
| 693 | * Java creates a {@code BigDecimal} which is exactly equal to |
| 694 | * 0.1 (an unscaled value of 1, with a scale of 1), but it is |
| 695 | * actually equal to |
| 696 | * 0.1000000000000000055511151231257827021181583404541015625. |
| 697 | * This is because 0.1 cannot be represented exactly as a |
| 698 | * {@code double} (or, for that matter, as a binary fraction of |
| 699 | * any finite length). Thus, the value that is being passed |
| 700 | * <i>in</i> to the constructor is not exactly equal to 0.1, |
| 701 | * appearances notwithstanding. |
| 702 | * |
| 703 | * <li> |
| 704 | * The {@code String} constructor, on the other hand, is |
| 705 | * perfectly predictable: writing {@code new BigDecimal("0.1")} |
| 706 | * creates a {@code BigDecimal} which is <i>exactly</i> equal to |
| 707 | * 0.1, as one would expect. Therefore, it is generally |
| 708 | * recommended that the {@linkplain #BigDecimal(String) |
| 709 | * <tt>String</tt> constructor} be used in preference to this one. |
| 710 | * |
| 711 | * <li> |
| 712 | * When a {@code double} must be used as a source for a |
| 713 | * {@code BigDecimal}, note that this constructor provides an |
| 714 | * exact conversion; it does not give the same result as |
| 715 | * converting the {@code double} to a {@code String} using the |
| 716 | * {@link Double#toString(double)} method and then using the |
| 717 | * {@link #BigDecimal(String)} constructor. To get that result, |
| 718 | * use the {@code static} {@link #valueOf(double)} method. |
| 719 | * </ol> |
| 720 | * |
| 721 | * @param val {@code double} value to be converted to |
| 722 | * {@code BigDecimal}. |
| 723 | * @throws NumberFormatException if {@code val} is infinite or NaN. |
| 724 | */ |
| 725 | public BigDecimal(double val) { |
| 726 | if (Double.isInfinite(val) || Double.isNaN(val)) |
| 727 | throw new NumberFormatException("Infinite or NaN"); |
| 728 | |
| 729 | // Translate the double into sign, exponent and significand, according |
| 730 | // to the formulae in JLS, Section 20.10.22. |
| 731 | long valBits = Double.doubleToLongBits(val); |
| 732 | int sign = ((valBits >> 63)==0 ? 1 : -1); |
| 733 | int exponent = (int) ((valBits >> 52) & 0x7ffL); |
| 734 | long significand = (exponent==0 ? (valBits & ((1L<<52) - 1)) << 1 |
| 735 | : (valBits & ((1L<<52) - 1)) | (1L<<52)); |
| 736 | exponent -= 1075; |
| 737 | // At this point, val == sign * significand * 2**exponent. |
| 738 | |
| 739 | /* |
| 740 | * Special case zero to supress nonterminating normalization |
| 741 | * and bogus scale calculation. |
| 742 | */ |
| 743 | if (significand == 0) { |
| 744 | intVal = BigInteger.ZERO; |
| 745 | intCompact = 0; |
| 746 | precision = 1; |
| 747 | return; |
| 748 | } |
| 749 | |
| 750 | // Normalize |
| 751 | while((significand & 1) == 0) { // i.e., significand is even |
| 752 | significand >>= 1; |
| 753 | exponent++; |
| 754 | } |
| 755 | |
| 756 | // Calculate intVal and scale |
| 757 | intVal = BigInteger.valueOf(sign*significand); |
| 758 | if (exponent < 0) { |
| 759 | intVal = intVal.multiply(BigInteger.valueOf(5).pow(-exponent)); |
| 760 | scale = -exponent; |
| 761 | } else if (exponent > 0) { |
| 762 | intVal = intVal.multiply(BigInteger.valueOf(2).pow(exponent)); |
| 763 | } |
| 764 | if (intVal.bitLength() <= MAX_BIGINT_BITS) { |
| 765 | intCompact = intVal.longValue(); |
| 766 | } |
| 767 | } |
| 768 | |
| 769 | /** |
| 770 | * Translates a {@code double} into a {@code BigDecimal}, with |
| 771 | * rounding according to the context settings. The scale of the |
| 772 | * {@code BigDecimal} is the smallest value such that |
| 773 | * <tt>(10<sup>scale</sup> × val)</tt> is an integer. |
| 774 | * |
| 775 | * <p>The results of this constructor can be somewhat unpredictable |
| 776 | * and its use is generally not recommended; see the notes under |
| 777 | * the {@link #BigDecimal(double)} constructor. |
| 778 | * |
| 779 | * @param val {@code double} value to be converted to |
| 780 | * {@code BigDecimal}. |
| 781 | * @param mc the context to use. |
| 782 | * @throws ArithmeticException if the result is inexact but the |
| 783 | * RoundingMode is UNNECESSARY. |
| 784 | * @throws NumberFormatException if {@code val} is infinite or NaN. |
| 785 | * @since 1.5 |
| 786 | */ |
| 787 | public BigDecimal(double val, MathContext mc) { |
| 788 | this(val); |
| 789 | if (mc.precision > 0) |
| 790 | roundThis(mc); |
| 791 | } |
| 792 | |
| 793 | /** |
| 794 | * Translates a {@code BigInteger} into a {@code BigDecimal}. |
| 795 | * The scale of the {@code BigDecimal} is zero. |
| 796 | * |
| 797 | * @param val {@code BigInteger} value to be converted to |
| 798 | * {@code BigDecimal}. |
| 799 | */ |
| 800 | public BigDecimal(BigInteger val) { |
| 801 | intVal = val; |
| 802 | if (val.bitLength() <= MAX_BIGINT_BITS) { |
| 803 | intCompact = val.longValue(); |
| 804 | } |
| 805 | } |
| 806 | |
| 807 | /** |
| 808 | * Translates a {@code BigInteger} into a {@code BigDecimal} |
| 809 | * rounding according to the context settings. The scale of the |
| 810 | * {@code BigDecimal} is zero. |
| 811 | * |
| 812 | * @param val {@code BigInteger} value to be converted to |
| 813 | * {@code BigDecimal}. |
| 814 | * @param mc the context to use. |
| 815 | * @throws ArithmeticException if the result is inexact but the |
| 816 | * rounding mode is {@code UNNECESSARY}. |
| 817 | * @since 1.5 |
| 818 | */ |
| 819 | public BigDecimal(BigInteger val, MathContext mc) { |
| 820 | intVal = val; |
| 821 | if (mc.precision > 0) |
| 822 | roundThis(mc); |
| 823 | } |
| 824 | |
| 825 | /** |
| 826 | * Translates a {@code BigInteger} unscaled value and an |
| 827 | * {@code int} scale into a {@code BigDecimal}. The value of |
| 828 | * the {@code BigDecimal} is |
| 829 | * <tt>(unscaledVal × 10<sup>-scale</sup>)</tt>. |
| 830 | * |
| 831 | * @param unscaledVal unscaled value of the {@code BigDecimal}. |
| 832 | * @param scale scale of the {@code BigDecimal}. |
| 833 | */ |
| 834 | public BigDecimal(BigInteger unscaledVal, int scale) { |
| 835 | // Negative scales are now allowed |
| 836 | intVal = unscaledVal; |
| 837 | this.scale = scale; |
| 838 | if (unscaledVal.bitLength() <= MAX_BIGINT_BITS) { |
| 839 | intCompact = unscaledVal.longValue(); |
| 840 | } |
| 841 | } |
| 842 | |
| 843 | /** |
| 844 | * Translates a {@code BigInteger} unscaled value and an |
| 845 | * {@code int} scale into a {@code BigDecimal}, with rounding |
| 846 | * according to the context settings. The value of the |
| 847 | * {@code BigDecimal} is <tt>(unscaledVal × |
| 848 | * 10<sup>-scale</sup>)</tt>, rounded according to the |
| 849 | * {@code precision} and rounding mode settings. |
| 850 | * |
| 851 | * @param unscaledVal unscaled value of the {@code BigDecimal}. |
| 852 | * @param scale scale of the {@code BigDecimal}. |
| 853 | * @param mc the context to use. |
| 854 | * @throws ArithmeticException if the result is inexact but the |
| 855 | * rounding mode is {@code UNNECESSARY}. |
| 856 | * @since 1.5 |
| 857 | */ |
| 858 | public BigDecimal(BigInteger unscaledVal, int scale, MathContext mc) { |
| 859 | intVal = unscaledVal; |
| 860 | this.scale = scale; |
| 861 | if (mc.precision > 0) |
| 862 | roundThis(mc); |
| 863 | } |
| 864 | |
| 865 | /** |
| 866 | * Translates an {@code int} into a {@code BigDecimal}. The |
| 867 | * scale of the {@code BigDecimal} is zero. |
| 868 | * |
| 869 | * @param val {@code int} value to be converted to |
| 870 | * {@code BigDecimal}. |
| 871 | * @since 1.5 |
| 872 | */ |
| 873 | public BigDecimal(int val) { |
| 874 | intCompact = val; |
| 875 | } |
| 876 | |
| 877 | /** |
| 878 | * Translates an {@code int} into a {@code BigDecimal}, with |
| 879 | * rounding according to the context settings. The scale of the |
| 880 | * {@code BigDecimal}, before any rounding, is zero. |
| 881 | * |
| 882 | * @param val {@code int} value to be converted to {@code BigDecimal}. |
| 883 | * @param mc the context to use. |
| 884 | * @throws ArithmeticException if the result is inexact but the |
| 885 | * rounding mode is {@code UNNECESSARY}. |
| 886 | * @since 1.5 |
| 887 | */ |
| 888 | public BigDecimal(int val, MathContext mc) { |
| 889 | intCompact = val; |
| 890 | if (mc.precision > 0) |
| 891 | roundThis(mc); |
| 892 | } |
| 893 | |
| 894 | /** |
| 895 | * Translates a {@code long} into a {@code BigDecimal}. The |
| 896 | * scale of the {@code BigDecimal} is zero. |
| 897 | * |
| 898 | * @param val {@code long} value to be converted to {@code BigDecimal}. |
| 899 | * @since 1.5 |
| 900 | */ |
| 901 | public BigDecimal(long val) { |
| 902 | if (compactLong(val)) |
| 903 | intCompact = val; |
| 904 | else |
| 905 | intVal = BigInteger.valueOf(val); |
| 906 | } |
| 907 | |
| 908 | /** |
| 909 | * Translates a {@code long} into a {@code BigDecimal}, with |
| 910 | * rounding according to the context settings. The scale of the |
| 911 | * {@code BigDecimal}, before any rounding, is zero. |
| 912 | * |
| 913 | * @param val {@code long} value to be converted to {@code BigDecimal}. |
| 914 | * @param mc the context to use. |
| 915 | * @throws ArithmeticException if the result is inexact but the |
| 916 | * rounding mode is {@code UNNECESSARY}. |
| 917 | * @since 1.5 |
| 918 | */ |
| 919 | public BigDecimal(long val, MathContext mc) { |
| 920 | if (compactLong(val)) |
| 921 | intCompact = val; |
| 922 | else |
| 923 | intVal = BigInteger.valueOf(val); |
| 924 | if (mc.precision > 0) |
| 925 | roundThis(mc); |
| 926 | } |
| 927 | |
| 928 | /** |
| 929 | * Trusted internal constructor |
| 930 | */ |
| 931 | private BigDecimal(long val, int scale) { |
| 932 | this.intCompact = val; |
| 933 | this.scale = scale; |
| 934 | } |
| 935 | |
| 936 | /** |
| 937 | * Trusted internal constructor |
| 938 | */ |
| 939 | private BigDecimal(BigInteger intVal, long val, int scale) { |
| 940 | this.intVal = intVal; |
| 941 | this.intCompact = val; |
| 942 | this.scale = scale; |
| 943 | } |
| 944 | |
| 945 | // Static Factory Methods |
| 946 | |
| 947 | /** |
| 948 | * Translates a {@code long} unscaled value and an |
| 949 | * {@code int} scale into a {@code BigDecimal}. This |
| 950 | * {@literal "static factory method"} is provided in preference to |
| 951 | * a ({@code long}, {@code int}) constructor because it |
| 952 | * allows for reuse of frequently used {@code BigDecimal} values.. |
| 953 | * |
| 954 | * @param unscaledVal unscaled value of the {@code BigDecimal}. |
| 955 | * @param scale scale of the {@code BigDecimal}. |
| 956 | * @return a {@code BigDecimal} whose value is |
| 957 | * <tt>(unscaledVal × 10<sup>-scale</sup>)</tt>. |
| 958 | */ |
| 959 | public static BigDecimal valueOf(long unscaledVal, int scale) { |
| 960 | if (scale == 0 && unscaledVal >= 0 && unscaledVal <= 10) { |
| 961 | return zeroThroughTen[(int)unscaledVal]; |
| 962 | } |
| 963 | if (compactLong(unscaledVal)) |
| 964 | return new BigDecimal(unscaledVal, scale); |
| 965 | return new BigDecimal(BigInteger.valueOf(unscaledVal), scale); |
| 966 | } |
| 967 | |
| 968 | /** |
| 969 | * Translates a {@code long} value into a {@code BigDecimal} |
| 970 | * with a scale of zero. This {@literal "static factory method"} |
| 971 | * is provided in preference to a ({@code long}) constructor |
| 972 | * because it allows for reuse of frequently used |
| 973 | * {@code BigDecimal} values. |
| 974 | * |
| 975 | * @param val value of the {@code BigDecimal}. |
| 976 | * @return a {@code BigDecimal} whose value is {@code val}. |
| 977 | */ |
| 978 | public static BigDecimal valueOf(long val) { |
| 979 | return valueOf(val, 0); |
| 980 | } |
| 981 | |
| 982 | /** |
| 983 | * Translates a {@code double} into a {@code BigDecimal}, using |
| 984 | * the {@code double}'s canonical string representation provided |
| 985 | * by the {@link Double#toString(double)} method. |
| 986 | * |
| 987 | * <p><b>Note:</b> This is generally the preferred way to convert |
| 988 | * a {@code double} (or {@code float}) into a |
| 989 | * {@code BigDecimal}, as the value returned is equal to that |
| 990 | * resulting from constructing a {@code BigDecimal} from the |
| 991 | * result of using {@link Double#toString(double)}. |
| 992 | * |
| 993 | * @param val {@code double} to convert to a {@code BigDecimal}. |
| 994 | * @return a {@code BigDecimal} whose value is equal to or approximately |
| 995 | * equal to the value of {@code val}. |
| 996 | * @throws NumberFormatException if {@code val} is infinite or NaN. |
| 997 | * @since 1.5 |
| 998 | */ |
| 999 | public static BigDecimal valueOf(double val) { |
| 1000 | // Reminder: a zero double returns '0.0', so we cannot fastpath |
| 1001 | // to use the constant ZERO. This might be important enough to |
| 1002 | // justify a factory approach, a cache, or a few private |
| 1003 | // constants, later. |
| 1004 | return new BigDecimal(Double.toString(val)); |
| 1005 | } |
| 1006 | |
| 1007 | // Arithmetic Operations |
| 1008 | /** |
| 1009 | * Returns a {@code BigDecimal} whose value is {@code (this + |
| 1010 | * augend)}, and whose scale is {@code max(this.scale(), |
| 1011 | * augend.scale())}. |
| 1012 | * |
| 1013 | * @param augend value to be added to this {@code BigDecimal}. |
| 1014 | * @return {@code this + augend} |
| 1015 | */ |
| 1016 | public BigDecimal add(BigDecimal augend) { |
| 1017 | BigDecimal arg[] = {this, augend}; |
| 1018 | matchScale(arg); |
| 1019 | |
| 1020 | long x = arg[0].intCompact; |
| 1021 | long y = arg[1].intCompact; |
| 1022 | |
| 1023 | // Might be able to do a more clever check incorporating the |
| 1024 | // inflated check into the overflow computation. |
| 1025 | if (x != INFLATED && y != INFLATED) { |
| 1026 | long sum = x + y; |
| 1027 | /* |
| 1028 | * If the sum is not an overflowed value, continue to use |
| 1029 | * the compact representation. if either of x or y is |
| 1030 | * INFLATED, the sum should also be regarded as an |
| 1031 | * overflow. See "Hacker's Delight" section 2-12 for |
| 1032 | * explanation of the overflow test. |
| 1033 | */ |
| 1034 | if ( (((sum ^ x) & (sum ^ y)) >> 63) == 0L ) // not overflowed |
| 1035 | return BigDecimal.valueOf(sum, arg[0].scale); |
| 1036 | } |
| 1037 | return new BigDecimal(arg[0].inflate().intVal.add(arg[1].inflate().intVal), arg[0].scale); |
| 1038 | } |
| 1039 | |
| 1040 | /** |
| 1041 | * Returns a {@code BigDecimal} whose value is {@code (this + augend)}, |
| 1042 | * with rounding according to the context settings. |
| 1043 | * |
| 1044 | * If either number is zero and the precision setting is nonzero then |
| 1045 | * the other number, rounded if necessary, is used as the result. |
| 1046 | * |
| 1047 | * @param augend value to be added to this {@code BigDecimal}. |
| 1048 | * @param mc the context to use. |
| 1049 | * @return {@code this + augend}, rounded as necessary. |
| 1050 | * @throws ArithmeticException if the result is inexact but the |
| 1051 | * rounding mode is {@code UNNECESSARY}. |
| 1052 | * @since 1.5 |
| 1053 | */ |
| 1054 | public BigDecimal add(BigDecimal augend, MathContext mc) { |
| 1055 | if (mc.precision == 0) |
| 1056 | return add(augend); |
| 1057 | BigDecimal lhs = this; |
| 1058 | |
| 1059 | // Could optimize if values are compact |
| 1060 | this.inflate(); |
| 1061 | augend.inflate(); |
| 1062 | |
| 1063 | // If either number is zero then the other number, rounded and |
| 1064 | // scaled if necessary, is used as the result. |
| 1065 | { |
| 1066 | boolean lhsIsZero = lhs.signum() == 0; |
| 1067 | boolean augendIsZero = augend.signum() == 0; |
| 1068 | |
| 1069 | if (lhsIsZero || augendIsZero) { |
| 1070 | int preferredScale = Math.max(lhs.scale(), augend.scale()); |
| 1071 | BigDecimal result; |
| 1072 | |
| 1073 | // Could use a factory for zero instead of a new object |
| 1074 | if (lhsIsZero && augendIsZero) |
| 1075 | return new BigDecimal(BigInteger.ZERO, 0, preferredScale); |
| 1076 | |
| 1077 | |
| 1078 | result = lhsIsZero ? augend.doRound(mc) : lhs.doRound(mc); |
| 1079 | |
| 1080 | if (result.scale() == preferredScale) |
| 1081 | return result; |
| 1082 | else if (result.scale() > preferredScale) |
| 1083 | return new BigDecimal(result.intVal, result.intCompact, result.scale). |
| 1084 | stripZerosToMatchScale(preferredScale); |
| 1085 | else { // result.scale < preferredScale |
| 1086 | int precisionDiff = mc.precision - result.precision(); |
| 1087 | int scaleDiff = preferredScale - result.scale(); |
| 1088 | |
| 1089 | if (precisionDiff >= scaleDiff) |
| 1090 | return result.setScale(preferredScale); // can achieve target scale |
| 1091 | else |
| 1092 | return result.setScale(result.scale() + precisionDiff); |
| 1093 | } |
| 1094 | } |
| 1095 | } |
| 1096 | |
| 1097 | long padding = (long)lhs.scale - augend.scale; |
| 1098 | if (padding != 0) { // scales differ; alignment needed |
| 1099 | BigDecimal arg[] = preAlign(lhs, augend, padding, mc); |
| 1100 | matchScale(arg); |
| 1101 | lhs = arg[0]; |
| 1102 | augend = arg[1]; |
| 1103 | } |
| 1104 | |
| 1105 | return new BigDecimal(lhs.inflate().intVal.add(augend.inflate().intVal), |
| 1106 | lhs.scale).doRound(mc); |
| 1107 | } |
| 1108 | |
| 1109 | /** |
| 1110 | * Returns an array of length two, the sum of whose entries is |
| 1111 | * equal to the rounded sum of the {@code BigDecimal} arguments. |
| 1112 | * |
| 1113 | * <p>If the digit positions of the arguments have a sufficient |
| 1114 | * gap between them, the value smaller in magnitude can be |
| 1115 | * condensed into a {@literal "sticky bit"} and the end result will |
| 1116 | * round the same way <em>if</em> the precision of the final |
| 1117 | * result does not include the high order digit of the small |
| 1118 | * magnitude operand. |
| 1119 | * |
| 1120 | * <p>Note that while strictly speaking this is an optimization, |
| 1121 | * it makes a much wider range of additions practical. |
| 1122 | * |
| 1123 | * <p>This corresponds to a pre-shift operation in a fixed |
| 1124 | * precision floating-point adder; this method is complicated by |
| 1125 | * variable precision of the result as determined by the |
| 1126 | * MathContext. A more nuanced operation could implement a |
| 1127 | * {@literal "right shift"} on the smaller magnitude operand so |
| 1128 | * that the number of digits of the smaller operand could be |
| 1129 | * reduced even though the significands partially overlapped. |
| 1130 | */ |
| 1131 | private BigDecimal[] preAlign(BigDecimal lhs, BigDecimal augend, |
| 1132 | long padding, MathContext mc) { |
| 1133 | assert padding != 0; |
| 1134 | BigDecimal big; |
| 1135 | BigDecimal small; |
| 1136 | |
| 1137 | if (padding < 0) { // lhs is big; augend is small |
| 1138 | big = lhs; |
| 1139 | small = augend; |
| 1140 | } else { // lhs is small; augend is big |
| 1141 | big = augend; |
| 1142 | small = lhs; |
| 1143 | } |
| 1144 | |
| 1145 | /* |
| 1146 | * This is the estimated scale of an ulp of the result; it |
| 1147 | * assumes that the result doesn't have a carry-out on a true |
| 1148 | * add (e.g. 999 + 1 => 1000) or any subtractive cancellation |
| 1149 | * on borrowing (e.g. 100 - 1.2 => 98.8) |
| 1150 | */ |
| 1151 | long estResultUlpScale = (long)big.scale - big.precision() + mc.precision; |
| 1152 | |
| 1153 | /* |
| 1154 | * The low-order digit position of big is big.scale(). This |
| 1155 | * is true regardless of whether big has a positive or |
| 1156 | * negative scale. The high-order digit position of small is |
| 1157 | * small.scale - (small.precision() - 1). To do the full |
| 1158 | * condensation, the digit positions of big and small must be |
| 1159 | * disjoint *and* the digit positions of small should not be |
| 1160 | * directly visible in the result. |
| 1161 | */ |
| 1162 | long smallHighDigitPos = (long)small.scale - small.precision() + 1; |
| 1163 | if (smallHighDigitPos > big.scale + 2 && // big and small disjoint |
| 1164 | smallHighDigitPos > estResultUlpScale + 2) { // small digits not visible |
| 1165 | small = BigDecimal.valueOf(small.signum(), |
| 1166 | this.checkScale(Math.max(big.scale, estResultUlpScale) + 3)); |
| 1167 | } |
| 1168 | |
| 1169 | // Since addition is symmetric, preserving input order in |
| 1170 | // returned operands doesn't matter |
| 1171 | BigDecimal[] result = {big, small}; |
| 1172 | return result; |
| 1173 | } |
| 1174 | |
| 1175 | /** |
| 1176 | * Returns a {@code BigDecimal} whose value is {@code (this - |
| 1177 | * subtrahend)}, and whose scale is {@code max(this.scale(), |
| 1178 | * subtrahend.scale())}. |
| 1179 | * |
| 1180 | * @param subtrahend value to be subtracted from this {@code BigDecimal}. |
| 1181 | * @return {@code this - subtrahend} |
| 1182 | */ |
| 1183 | public BigDecimal subtract(BigDecimal subtrahend) { |
| 1184 | BigDecimal arg[] = {this, subtrahend}; |
| 1185 | matchScale(arg); |
| 1186 | |
| 1187 | long x = arg[0].intCompact; |
| 1188 | long y = arg[1].intCompact; |
| 1189 | |
| 1190 | // Might be able to do a more clever check incorporating the |
| 1191 | // inflated check into the overflow computation. |
| 1192 | if (x != INFLATED && y != INFLATED) { |
| 1193 | long difference = x - y; |
| 1194 | /* |
| 1195 | * If the difference is not an overflowed value, continue |
| 1196 | * to use the compact representation. if either of x or y |
| 1197 | * is INFLATED, the difference should also be regarded as |
| 1198 | * an overflow. See "Hacker's Delight" section 2-12 for |
| 1199 | * explanation of the overflow test. |
| 1200 | */ |
| 1201 | if ( ((x ^ y) & (difference ^ x) ) >> 63 == 0L ) // not overflowed |
| 1202 | return BigDecimal.valueOf(difference, arg[0].scale); |
| 1203 | } |
| 1204 | return new BigDecimal(arg[0].inflate().intVal.subtract(arg[1].inflate().intVal), |
| 1205 | arg[0].scale); |
| 1206 | } |
| 1207 | |
| 1208 | /** |
| 1209 | * Returns a {@code BigDecimal} whose value is {@code (this - subtrahend)}, |
| 1210 | * with rounding according to the context settings. |
| 1211 | * |
| 1212 | * If {@code subtrahend} is zero then this, rounded if necessary, is used as the |
| 1213 | * result. If this is zero then the result is {@code subtrahend.negate(mc)}. |
| 1214 | * |
| 1215 | * @param subtrahend value to be subtracted from this {@code BigDecimal}. |
| 1216 | * @param mc the context to use. |
| 1217 | * @return {@code this - subtrahend}, rounded as necessary. |
| 1218 | * @throws ArithmeticException if the result is inexact but the |
| 1219 | * rounding mode is {@code UNNECESSARY}. |
| 1220 | * @since 1.5 |
| 1221 | */ |
| 1222 | public BigDecimal subtract(BigDecimal subtrahend, MathContext mc) { |
| 1223 | if (mc.precision == 0) |
| 1224 | return subtract(subtrahend); |
| 1225 | // share the special rounding code in add() |
| 1226 | this.inflate(); |
| 1227 | subtrahend.inflate(); |
| 1228 | BigDecimal rhs = new BigDecimal(subtrahend.intVal.negate(), subtrahend.scale); |
| 1229 | rhs.precision = subtrahend.precision; |
| 1230 | return add(rhs, mc); |
| 1231 | } |
| 1232 | |
| 1233 | /** |
| 1234 | * Returns a {@code BigDecimal} whose value is <tt>(this × |
| 1235 | * multiplicand)</tt>, and whose scale is {@code (this.scale() + |
| 1236 | * multiplicand.scale())}. |
| 1237 | * |
| 1238 | * @param multiplicand value to be multiplied by this {@code BigDecimal}. |
| 1239 | * @return {@code this * multiplicand} |
| 1240 | */ |
| 1241 | public BigDecimal multiply(BigDecimal multiplicand) { |
| 1242 | long x = this.intCompact; |
| 1243 | long y = multiplicand.intCompact; |
| 1244 | int productScale = checkScale((long)scale+multiplicand.scale); |
| 1245 | |
| 1246 | // Might be able to do a more clever check incorporating the |
| 1247 | // inflated check into the overflow computation. |
| 1248 | if (x != INFLATED && y != INFLATED) { |
| 1249 | /* |
| 1250 | * If the product is not an overflowed value, continue |
| 1251 | * to use the compact representation. if either of x or y |
| 1252 | * is INFLATED, the product should also be regarded as |
| 1253 | * an overflow. See "Hacker's Delight" section 2-12 for |
| 1254 | * explanation of the overflow test. |
| 1255 | */ |
| 1256 | long product = x * y; |
| 1257 | if ( !(y != 0L && product/y != x) ) // not overflowed |
| 1258 | return BigDecimal.valueOf(product, productScale); |
| 1259 | } |
| 1260 | |
| 1261 | BigDecimal result = new BigDecimal(this.inflate().intVal.multiply(multiplicand.inflate().intVal), productScale); |
| 1262 | return result; |
| 1263 | } |
| 1264 | |
| 1265 | /** |
| 1266 | * Returns a {@code BigDecimal} whose value is <tt>(this × |
| 1267 | * multiplicand)</tt>, with rounding according to the context settings. |
| 1268 | * |
| 1269 | * @param multiplicand value to be multiplied by this {@code BigDecimal}. |
| 1270 | * @param mc the context to use. |
| 1271 | * @return {@code this * multiplicand}, rounded as necessary. |
| 1272 | * @throws ArithmeticException if the result is inexact but the |
| 1273 | * rounding mode is {@code UNNECESSARY}. |
| 1274 | * @since 1.5 |
| 1275 | */ |
| 1276 | public BigDecimal multiply(BigDecimal multiplicand, MathContext mc) { |
| 1277 | if (mc.precision == 0) |
| 1278 | return multiply(multiplicand); |
| 1279 | BigDecimal lhs = this; |
| 1280 | return lhs.inflate().multiply(multiplicand.inflate()).doRound(mc); |
| 1281 | } |
| 1282 | |
| 1283 | /** |
| 1284 | * Returns a {@code BigDecimal} whose value is {@code (this / |
| 1285 | * divisor)}, and whose scale is as specified. If rounding must |
| 1286 | * be performed to generate a result with the specified scale, the |
| 1287 | * specified rounding mode is applied. |
| 1288 | * |
| 1289 | * <p>The new {@link #divide(BigDecimal, int, RoundingMode)} method |
| 1290 | * should be used in preference to this legacy method. |
| 1291 | * |
| 1292 | * @param divisor value by which this {@code BigDecimal} is to be divided. |
| 1293 | * @param scale scale of the {@code BigDecimal} quotient to be returned. |
| 1294 | * @param roundingMode rounding mode to apply. |
| 1295 | * @return {@code this / divisor} |
| 1296 | * @throws ArithmeticException if {@code divisor} is zero, |
| 1297 | * {@code roundingMode==ROUND_UNNECESSARY} and |
| 1298 | * the specified scale is insufficient to represent the result |
| 1299 | * of the division exactly. |
| 1300 | * @throws IllegalArgumentException if {@code roundingMode} does not |
| 1301 | * represent a valid rounding mode. |
| 1302 | * @see #ROUND_UP |
| 1303 | * @see #ROUND_DOWN |
| 1304 | * @see #ROUND_CEILING |
| 1305 | * @see #ROUND_FLOOR |
| 1306 | * @see #ROUND_HALF_UP |
| 1307 | * @see #ROUND_HALF_DOWN |
| 1308 | * @see #ROUND_HALF_EVEN |
| 1309 | * @see #ROUND_UNNECESSARY |
| 1310 | */ |
| 1311 | public BigDecimal divide(BigDecimal divisor, int scale, int roundingMode) { |
| 1312 | /* |
| 1313 | * IMPLEMENTATION NOTE: This method *must* return a new object |
| 1314 | * since dropDigits uses divide to generate a value whose |
| 1315 | * scale is then modified. |
| 1316 | */ |
| 1317 | if (roundingMode < ROUND_UP || roundingMode > ROUND_UNNECESSARY) |
| 1318 | throw new IllegalArgumentException("Invalid rounding mode"); |
| 1319 | /* |
| 1320 | * Rescale dividend or divisor (whichever can be "upscaled" to |
| 1321 | * produce correctly scaled quotient). |
| 1322 | * Take care to detect out-of-range scales |
| 1323 | */ |
| 1324 | BigDecimal dividend; |
| 1325 | if (checkScale((long)scale + divisor.scale) >= this.scale) { |
| 1326 | dividend = this.setScale(scale + divisor.scale); |
| 1327 | } else { |
| 1328 | dividend = this; |
| 1329 | divisor = divisor.setScale(checkScale((long)this.scale - scale)); |
| 1330 | } |
| 1331 | |
| 1332 | boolean compact = dividend.intCompact != INFLATED && divisor.intCompact != INFLATED; |
| 1333 | long div = INFLATED; |
| 1334 | long rem = INFLATED;; |
| 1335 | BigInteger q=null, r=null; |
| 1336 | |
| 1337 | if (compact) { |
| 1338 | div = dividend.intCompact / divisor.intCompact; |
| 1339 | rem = dividend.intCompact % divisor.intCompact; |
| 1340 | } else { |
| 1341 | // Do the division and return result if it's exact. |
| 1342 | BigInteger i[] = dividend.inflate().intVal.divideAndRemainder(divisor.inflate().intVal); |
| 1343 | q = i[0]; |
| 1344 | r = i[1]; |
| 1345 | } |
| 1346 | |
| 1347 | // Check for exact result |
| 1348 | if (compact) { |
| 1349 | if (rem == 0) |
| 1350 | return new BigDecimal(div, scale); |
| 1351 | } else { |
| 1352 | if (r.signum() == 0) |
| 1353 | return new BigDecimal(q, scale); |
| 1354 | } |
| 1355 | |
| 1356 | if (roundingMode == ROUND_UNNECESSARY) // Rounding prohibited |
| 1357 | throw new ArithmeticException("Rounding necessary"); |
| 1358 | |
| 1359 | /* Round as appropriate */ |
| 1360 | int signum = dividend.signum() * divisor.signum(); // Sign of result |
| 1361 | boolean increment; |
| 1362 | if (roundingMode == ROUND_UP) { // Away from zero |
| 1363 | increment = true; |
| 1364 | } else if (roundingMode == ROUND_DOWN) { // Towards zero |
| 1365 | increment = false; |
| 1366 | } else if (roundingMode == ROUND_CEILING) { // Towards +infinity |
| 1367 | increment = (signum > 0); |
| 1368 | } else if (roundingMode == ROUND_FLOOR) { // Towards -infinity |
| 1369 | increment = (signum < 0); |
| 1370 | } else { // Remaining modes based on nearest-neighbor determination |
| 1371 | int cmpFracHalf; |
| 1372 | if (compact) { |
| 1373 | cmpFracHalf = longCompareTo(Math.abs(2*rem), Math.abs(divisor.intCompact)); |
| 1374 | } else { |
| 1375 | // add(r) here is faster than multiply(2) or shiftLeft(1) |
| 1376 | cmpFracHalf= r.add(r).abs().compareTo(divisor.intVal.abs()); |
| 1377 | } |
| 1378 | if (cmpFracHalf < 0) { // We're closer to higher digit |
| 1379 | increment = false; |
| 1380 | } else if (cmpFracHalf > 0) { // We're closer to lower digit |
| 1381 | increment = true; |
| 1382 | } else { // We're dead-center |
| 1383 | if (roundingMode == ROUND_HALF_UP) |
| 1384 | increment = true; |
| 1385 | else if (roundingMode == ROUND_HALF_DOWN) |
| 1386 | increment = false; |
| 1387 | else { // roundingMode == ROUND_HALF_EVEN |
| 1388 | if (compact) |
| 1389 | increment = (div & 1L) != 0L; |
| 1390 | else |
| 1391 | increment = q.testBit(0); // true iff q is odd |
| 1392 | } |
| 1393 | } |
| 1394 | } |
| 1395 | |
| 1396 | if (compact) { |
| 1397 | if (increment) |
| 1398 | div += signum; // guaranteed not to overflow |
| 1399 | return new BigDecimal(div, scale); |
| 1400 | } else { |
| 1401 | return (increment |
| 1402 | ? new BigDecimal(q.add(BigInteger.valueOf(signum)), scale) |
| 1403 | : new BigDecimal(q, scale)); |
| 1404 | } |
| 1405 | } |
| 1406 | |
| 1407 | /** |
| 1408 | * Returns a {@code BigDecimal} whose value is {@code (this / |
| 1409 | * divisor)}, and whose scale is as specified. If rounding must |
| 1410 | * be performed to generate a result with the specified scale, the |
| 1411 | * specified rounding mode is applied. |
| 1412 | * |
| 1413 | * @param divisor value by which this {@code BigDecimal} is to be divided. |
| 1414 | * @param scale scale of the {@code BigDecimal} quotient to be returned. |
| 1415 | * @param roundingMode rounding mode to apply. |
| 1416 | * @return {@code this / divisor} |
| 1417 | * @throws ArithmeticException if {@code divisor} is zero, |
| 1418 | * {@code roundingMode==RoundingMode.UNNECESSARY} and |
| 1419 | * the specified scale is insufficient to represent the result |
| 1420 | * of the division exactly. |
| 1421 | * @since 1.5 |
| 1422 | */ |
| 1423 | public BigDecimal divide(BigDecimal divisor, int scale, RoundingMode roundingMode) { |
| 1424 | return divide(divisor, scale, roundingMode.oldMode); |
| 1425 | } |
| 1426 | |
| 1427 | /** |
| 1428 | * Returns a {@code BigDecimal} whose value is {@code (this / |
| 1429 | * divisor)}, and whose scale is {@code this.scale()}. If |
| 1430 | * rounding must be performed to generate a result with the given |
| 1431 | * scale, the specified rounding mode is applied. |
| 1432 | * |
| 1433 | * <p>The new {@link #divide(BigDecimal, RoundingMode)} method |
| 1434 | * should be used in preference to this legacy method. |
| 1435 | * |
| 1436 | * @param divisor value by which this {@code BigDecimal} is to be divided. |
| 1437 | * @param roundingMode rounding mode to apply. |
| 1438 | * @return {@code this / divisor} |
| 1439 | * @throws ArithmeticException if {@code divisor==0}, or |
| 1440 | * {@code roundingMode==ROUND_UNNECESSARY} and |
| 1441 | * {@code this.scale()} is insufficient to represent the result |
| 1442 | * of the division exactly. |
| 1443 | * @throws IllegalArgumentException if {@code roundingMode} does not |
| 1444 | * represent a valid rounding mode. |
| 1445 | * @see #ROUND_UP |
| 1446 | * @see #ROUND_DOWN |
| 1447 | * @see #ROUND_CEILING |
| 1448 | * @see #ROUND_FLOOR |
| 1449 | * @see #ROUND_HALF_UP |
| 1450 | * @see #ROUND_HALF_DOWN |
| 1451 | * @see #ROUND_HALF_EVEN |
| 1452 | * @see #ROUND_UNNECESSARY |
| 1453 | */ |
| 1454 | public BigDecimal divide(BigDecimal divisor, int roundingMode) { |
| 1455 | return this.divide(divisor, scale, roundingMode); |
| 1456 | } |
| 1457 | |
| 1458 | /** |
| 1459 | * Returns a {@code BigDecimal} whose value is {@code (this / |
| 1460 | * divisor)}, and whose scale is {@code this.scale()}. If |
| 1461 | * rounding must be performed to generate a result with the given |
| 1462 | * scale, the specified rounding mode is applied. |
| 1463 | * |
| 1464 | * @param divisor value by which this {@code BigDecimal} is to be divided. |
| 1465 | * @param roundingMode rounding mode to apply. |
| 1466 | * @return {@code this / divisor} |
| 1467 | * @throws ArithmeticException if {@code divisor==0}, or |
| 1468 | * {@code roundingMode==RoundingMode.UNNECESSARY} and |
| 1469 | * {@code this.scale()} is insufficient to represent the result |
| 1470 | * of the division exactly. |
| 1471 | * @since 1.5 |
| 1472 | */ |
| 1473 | public BigDecimal divide(BigDecimal divisor, RoundingMode roundingMode) { |
| 1474 | return this.divide(divisor, scale, roundingMode.oldMode); |
| 1475 | } |
| 1476 | |
| 1477 | /** |
| 1478 | * Returns a {@code BigDecimal} whose value is {@code (this / |
| 1479 | * divisor)}, and whose preferred scale is {@code (this.scale() - |
| 1480 | * divisor.scale())}; if the exact quotient cannot be |
| 1481 | * represented (because it has a non-terminating decimal |
| 1482 | * expansion) an {@code ArithmeticException} is thrown. |
| 1483 | * |
| 1484 | * @param divisor value by which this {@code BigDecimal} is to be divided. |
| 1485 | * @throws ArithmeticException if the exact quotient does not have a |
| 1486 | * terminating decimal expansion |
| 1487 | * @return {@code this / divisor} |
| 1488 | * @since 1.5 |
| 1489 | * @author Joseph D. Darcy |
| 1490 | */ |
| 1491 | public BigDecimal divide(BigDecimal divisor) { |
| 1492 | /* |
| 1493 | * Handle zero cases first. |
| 1494 | */ |
| 1495 | if (divisor.signum() == 0) { // x/0 |
| 1496 | if (this.signum() == 0) // 0/0 |
| 1497 | throw new ArithmeticException("Division undefined"); // NaN |
| 1498 | throw new ArithmeticException("Division by zero"); |
| 1499 | } |
| 1500 | |
| 1501 | // Calculate preferred scale |
| 1502 | int preferredScale = (int)Math.max(Math.min((long)this.scale() - divisor.scale(), |
| 1503 | Integer.MAX_VALUE), Integer.MIN_VALUE); |
| 1504 | if (this.signum() == 0) // 0/y |
| 1505 | return new BigDecimal(0, preferredScale); |
| 1506 | else { |
| 1507 | this.inflate(); |
| 1508 | divisor.inflate(); |
| 1509 | /* |
| 1510 | * If the quotient this/divisor has a terminating decimal |
| 1511 | * expansion, the expansion can have no more than |
| 1512 | * (a.precision() + ceil(10*b.precision)/3) digits. |
| 1513 | * Therefore, create a MathContext object with this |
| 1514 | * precision and do a divide with the UNNECESSARY rounding |
| 1515 | * mode. |
| 1516 | */ |
| 1517 | MathContext mc = new MathContext( (int)Math.min(this.precision() + |
| 1518 | (long)Math.ceil(10.0*divisor.precision()/3.0), |
| 1519 | Integer.MAX_VALUE), |
| 1520 | RoundingMode.UNNECESSARY); |
| 1521 | BigDecimal quotient; |
| 1522 | try { |
| 1523 | quotient = this.divide(divisor, mc); |
| 1524 | } catch (ArithmeticException e) { |
| 1525 | throw new ArithmeticException("Non-terminating decimal expansion; " + |
| 1526 | "no exact representable decimal result."); |
| 1527 | } |
| 1528 | |
| 1529 | int quotientScale = quotient.scale(); |
| 1530 | |
| 1531 | // divide(BigDecimal, mc) tries to adjust the quotient to |
| 1532 | // the desired one by removing trailing zeros; since the |
| 1533 | // exact divide method does not have an explicit digit |
| 1534 | // limit, we can add zeros too. |
| 1535 | |
| 1536 | if (preferredScale > quotientScale) |
| 1537 | return quotient.setScale(preferredScale); |
| 1538 | |
| 1539 | return quotient; |
| 1540 | } |
| 1541 | } |
| 1542 | |
| 1543 | /** |
| 1544 | * Returns a {@code BigDecimal} whose value is {@code (this / |
| 1545 | * divisor)}, with rounding according to the context settings. |
| 1546 | * |
| 1547 | * @param divisor value by which this {@code BigDecimal} is to be divided. |
| 1548 | * @param mc the context to use. |
| 1549 | * @return {@code this / divisor}, rounded as necessary. |
| 1550 | * @throws ArithmeticException if the result is inexact but the |
| 1551 | * rounding mode is {@code UNNECESSARY} or |
| 1552 | * {@code mc.precision == 0} and the quotient has a |
| 1553 | * non-terminating decimal expansion. |
| 1554 | * @since 1.5 |
| 1555 | */ |
| 1556 | public BigDecimal divide(BigDecimal divisor, MathContext mc) { |
| 1557 | if (mc.precision == 0) |
| 1558 | return divide(divisor); |
| 1559 | BigDecimal lhs = this.inflate(); // left-hand-side |
| 1560 | BigDecimal rhs = divisor.inflate(); // right-hand-side |
| 1561 | BigDecimal result; // work |
| 1562 | |
| 1563 | long preferredScale = (long)lhs.scale() - rhs.scale(); |
| 1564 | |
| 1565 | // Now calculate the answer. We use the existing |
| 1566 | // divide-and-round method, but as this rounds to scale we have |
| 1567 | // to normalize the values here to achieve the desired result. |
| 1568 | // For x/y we first handle y=0 and x=0, and then normalize x and |
| 1569 | // y to give x' and y' with the following constraints: |
| 1570 | // (a) 0.1 <= x' < 1 |
| 1571 | // (b) x' <= y' < 10*x' |
| 1572 | // Dividing x'/y' with the required scale set to mc.precision then |
| 1573 | // will give a result in the range 0.1 to 1 rounded to exactly |
| 1574 | // the right number of digits (except in the case of a result of |
| 1575 | // 1.000... which can arise when x=y, or when rounding overflows |
| 1576 | // The 1.000... case will reduce properly to 1. |
| 1577 | if (rhs.signum() == 0) { // x/0 |
| 1578 | if (lhs.signum() == 0) // 0/0 |
| 1579 | throw new ArithmeticException("Division undefined"); // NaN |
| 1580 | throw new ArithmeticException("Division by zero"); |
| 1581 | } |
| 1582 | if (lhs.signum() == 0) // 0/y |
| 1583 | return new BigDecimal(BigInteger.ZERO, |
| 1584 | (int)Math.max(Math.min(preferredScale, |
| 1585 | Integer.MAX_VALUE), |
| 1586 | Integer.MIN_VALUE)); |
| 1587 | |
| 1588 | BigDecimal xprime = new BigDecimal(lhs.intVal.abs(), lhs.precision()); |
| 1589 | BigDecimal yprime = new BigDecimal(rhs.intVal.abs(), rhs.precision()); |
| 1590 | // xprime and yprime are now both in range 0.1 through 0.999... |
| 1591 | if (mc.roundingMode == RoundingMode.CEILING || |
| 1592 | mc.roundingMode == RoundingMode.FLOOR) { |
| 1593 | // The floor (round toward negative infinity) and ceil |
| 1594 | // (round toward positive infinity) rounding modes are not |
| 1595 | // invariant under a sign flip. If xprime/yprime has a |
| 1596 | // different sign than lhs/rhs, the rounding mode must be |
| 1597 | // changed. |
| 1598 | if ((xprime.signum() != lhs.signum()) ^ |
| 1599 | (yprime.signum() != rhs.signum())) { |
| 1600 | mc = new MathContext(mc.precision, |
| 1601 | (mc.roundingMode==RoundingMode.CEILING)? |
| 1602 | RoundingMode.FLOOR:RoundingMode.CEILING); |
| 1603 | } |
| 1604 | } |
| 1605 | |
| 1606 | if (xprime.compareTo(yprime) > 0) // satisfy constraint (b) |
| 1607 | yprime.scale -= 1; // [that is, yprime *= 10] |
| 1608 | result = xprime.divide(yprime, mc.precision, mc.roundingMode.oldMode); |
| 1609 | // correct the scale of the result... |
| 1610 | result.scale = checkScale((long)yprime.scale - xprime.scale |
| 1611 | - (rhs.scale - lhs.scale) + mc.precision); |
| 1612 | // apply the sign |
| 1613 | if (lhs.signum() != rhs.signum()) |
| 1614 | result = result.negate(); |
| 1615 | // doRound, here, only affects 1000000000 case. |
| 1616 | result = result.doRound(mc); |
| 1617 | |
| 1618 | if (result.multiply(divisor).compareTo(this) == 0) { |
| 1619 | // Apply preferred scale rules for exact quotients |
| 1620 | return result.stripZerosToMatchScale(preferredScale); |
| 1621 | } |
| 1622 | else { |
| 1623 | return result; |
| 1624 | } |
| 1625 | } |
| 1626 | |
| 1627 | /** |
| 1628 | * Returns a {@code BigDecimal} whose value is the integer part |
| 1629 | * of the quotient {@code (this / divisor)} rounded down. The |
| 1630 | * preferred scale of the result is {@code (this.scale() - |
| 1631 | * divisor.scale())}. |
| 1632 | * |
| 1633 | * @param divisor value by which this {@code BigDecimal} is to be divided. |
| 1634 | * @return The integer part of {@code this / divisor}. |
| 1635 | * @throws ArithmeticException if {@code divisor==0} |
| 1636 | * @since 1.5 |
| 1637 | */ |
| 1638 | public BigDecimal divideToIntegralValue(BigDecimal divisor) { |
| 1639 | // Calculate preferred scale |
| 1640 | int preferredScale = (int)Math.max(Math.min((long)this.scale() - divisor.scale(), |
| 1641 | Integer.MAX_VALUE), Integer.MIN_VALUE); |
| 1642 | this.inflate(); |
| 1643 | divisor.inflate(); |
| 1644 | if (this.abs().compareTo(divisor.abs()) < 0) { |
| 1645 | // much faster when this << divisor |
| 1646 | return BigDecimal.valueOf(0, preferredScale); |
| 1647 | } |
| 1648 | |
| 1649 | if(this.signum() == 0 && divisor.signum() != 0) |
| 1650 | return this.setScale(preferredScale); |
| 1651 | |
| 1652 | // Perform a divide with enough digits to round to a correct |
| 1653 | // integer value; then remove any fractional digits |
| 1654 | |
| 1655 | int maxDigits = (int)Math.min(this.precision() + |
| 1656 | (long)Math.ceil(10.0*divisor.precision()/3.0) + |
| 1657 | Math.abs((long)this.scale() - divisor.scale()) + 2, |
| 1658 | Integer.MAX_VALUE); |
| 1659 | |
| 1660 | BigDecimal quotient = this.divide(divisor, new MathContext(maxDigits, |
| 1661 | RoundingMode.DOWN)); |
| 1662 | if (quotient.scale > 0) { |
| 1663 | quotient = quotient.setScale(0, RoundingMode.DOWN). |
| 1664 | stripZerosToMatchScale(preferredScale); |
| 1665 | } |
| 1666 | |
| 1667 | if (quotient.scale < preferredScale) { |
| 1668 | // pad with zeros if necessary |
| 1669 | quotient = quotient.setScale(preferredScale); |
| 1670 | } |
| 1671 | |
| 1672 | return quotient; |
| 1673 | } |
| 1674 | |
| 1675 | /** |
| 1676 | * Returns a {@code BigDecimal} whose value is the integer part |
| 1677 | * of {@code (this / divisor)}. Since the integer part of the |
| 1678 | * exact quotient does not depend on the rounding mode, the |
| 1679 | * rounding mode does not affect the values returned by this |
| 1680 | * method. The preferred scale of the result is |
| 1681 | * {@code (this.scale() - divisor.scale())}. An |
| 1682 | * {@code ArithmeticException} is thrown if the integer part of |
| 1683 | * the exact quotient needs more than {@code mc.precision} |
| 1684 | * digits. |
| 1685 | * |
| 1686 | * @param divisor value by which this {@code BigDecimal} is to be divided. |
| 1687 | * @param mc the context to use. |
| 1688 | * @return The integer part of {@code this / divisor}. |
| 1689 | * @throws ArithmeticException if {@code divisor==0} |
| 1690 | * @throws ArithmeticException if {@code mc.precision} {@literal >} 0 and the result |
| 1691 | * requires a precision of more than {@code mc.precision} digits. |
| 1692 | * @since 1.5 |
| 1693 | * @author Joseph D. Darcy |
| 1694 | */ |
| 1695 | public BigDecimal divideToIntegralValue(BigDecimal divisor, MathContext mc) { |
| 1696 | if (mc.precision == 0 || // exact result |
| 1697 | (this.abs().compareTo(divisor.abs()) < 0) ) // zero result |
| 1698 | return divideToIntegralValue(divisor); |
| 1699 | |
| 1700 | // Calculate preferred scale |
| 1701 | int preferredScale = (int)Math.max(Math.min((long)this.scale() - divisor.scale(), |
| 1702 | Integer.MAX_VALUE), Integer.MIN_VALUE); |
| 1703 | |
| 1704 | /* |
| 1705 | * Perform a normal divide to mc.precision digits. If the |
| 1706 | * remainder has absolute value less than the divisor, the |
| 1707 | * integer portion of the quotient fits into mc.precision |
| 1708 | * digits. Next, remove any fractional digits from the |
| 1709 | * quotient and adjust the scale to the preferred value. |
| 1710 | */ |
| 1711 | BigDecimal result = this.divide(divisor, new MathContext(mc.precision, |
| 1712 | RoundingMode.DOWN)); |
| 1713 | int resultScale = result.scale(); |
| 1714 | |
| 1715 | if (result.scale() < 0) { |
| 1716 | /* |
| 1717 | * Result is an integer. See if quotient represents the |
| 1718 | * full integer portion of the exact quotient; if it does, |
| 1719 | * the computed remainder will be less than the divisor. |
| 1720 | */ |
| 1721 | BigDecimal product = result.multiply(divisor); |
| 1722 | // If the quotient is the full integer value, |
| 1723 | // |dividend-product| < |divisor|. |
| 1724 | if (this.subtract(product).abs().compareTo(divisor.abs()) >= 0) { |
| 1725 | throw new ArithmeticException("Division impossible"); |
| 1726 | } |
| 1727 | } else if (result.scale() > 0) { |
| 1728 | /* |
| 1729 | * Integer portion of quotient will fit into precision |
| 1730 | * digits; recompute quotient to scale 0 to avoid double |
| 1731 | * rounding and then try to adjust, if necessary. |
| 1732 | */ |
| 1733 | result = result.setScale(0, RoundingMode.DOWN); |
| 1734 | } |
| 1735 | // else result.scale() == 0; |
| 1736 | |
| 1737 | int precisionDiff; |
| 1738 | if ((preferredScale > result.scale()) && |
| 1739 | (precisionDiff = mc.precision - result.precision()) > 0 ) { |
| 1740 | return result.setScale(result.scale() + |
| 1741 | Math.min(precisionDiff, preferredScale - result.scale) ); |
| 1742 | } else |
| 1743 | return result.stripZerosToMatchScale(preferredScale); |
| 1744 | } |
| 1745 | |
| 1746 | /** |
| 1747 | * Returns a {@code BigDecimal} whose value is {@code (this % divisor)}. |
| 1748 | * |
| 1749 | * <p>The remainder is given by |
| 1750 | * {@code this.subtract(this.divideToIntegralValue(divisor).multiply(divisor))}. |
| 1751 | * Note that this is not the modulo operation (the result can be |
| 1752 | * negative). |
| 1753 | * |
| 1754 | * @param divisor value by which this {@code BigDecimal} is to be divided. |
| 1755 | * @return {@code this % divisor}. |
| 1756 | * @throws ArithmeticException if {@code divisor==0} |
| 1757 | * @since 1.5 |
| 1758 | */ |
| 1759 | public BigDecimal remainder(BigDecimal divisor) { |
| 1760 | BigDecimal divrem[] = this.divideAndRemainder(divisor); |
| 1761 | return divrem[1]; |
| 1762 | } |
| 1763 | |
| 1764 | |
| 1765 | /** |
| 1766 | * Returns a {@code BigDecimal} whose value is {@code (this % |
| 1767 | * divisor)}, with rounding according to the context settings. |
| 1768 | * The {@code MathContext} settings affect the implicit divide |
| 1769 | * used to compute the remainder. The remainder computation |
| 1770 | * itself is by definition exact. Therefore, the remainder may |
| 1771 | * contain more than {@code mc.getPrecision()} digits. |
| 1772 | * |
| 1773 | * <p>The remainder is given by |
| 1774 | * {@code this.subtract(this.divideToIntegralValue(divisor, |
| 1775 | * mc).multiply(divisor))}. Note that this is not the modulo |
| 1776 | * operation (the result can be negative). |
| 1777 | * |
| 1778 | * @param divisor value by which this {@code BigDecimal} is to be divided. |
| 1779 | * @param mc the context to use. |
| 1780 | * @return {@code this % divisor}, rounded as necessary. |
| 1781 | * @throws ArithmeticException if {@code divisor==0} |
| 1782 | * @throws ArithmeticException if the result is inexact but the |
| 1783 | * rounding mode is {@code UNNECESSARY}, or {@code mc.precision} |
| 1784 | * {@literal >} 0 and the result of {@code this.divideToIntgralValue(divisor)} would |
| 1785 | * require a precision of more than {@code mc.precision} digits. |
| 1786 | * @see #divideToIntegralValue(java.math.BigDecimal, java.math.MathContext) |
| 1787 | * @since 1.5 |
| 1788 | */ |
| 1789 | public BigDecimal remainder(BigDecimal divisor, MathContext mc) { |
| 1790 | BigDecimal divrem[] = this.divideAndRemainder(divisor, mc); |
| 1791 | return divrem[1]; |
| 1792 | } |
| 1793 | |
| 1794 | /** |
| 1795 | * Returns a two-element {@code BigDecimal} array containing the |
| 1796 | * result of {@code divideToIntegralValue} followed by the result of |
| 1797 | * {@code remainder} on the two operands. |
| 1798 | * |
| 1799 | * <p>Note that if both the integer quotient and remainder are |
| 1800 | * needed, this method is faster than using the |
| 1801 | * {@code divideToIntegralValue} and {@code remainder} methods |
| 1802 | * separately because the division need only be carried out once. |
| 1803 | * |
| 1804 | * @param divisor value by which this {@code BigDecimal} is to be divided, |
| 1805 | * and the remainder computed. |
| 1806 | * @return a two element {@code BigDecimal} array: the quotient |
| 1807 | * (the result of {@code divideToIntegralValue}) is the initial element |
| 1808 | * and the remainder is the final element. |
| 1809 | * @throws ArithmeticException if {@code divisor==0} |
| 1810 | * @see #divideToIntegralValue(java.math.BigDecimal, java.math.MathContext) |
| 1811 | * @see #remainder(java.math.BigDecimal, java.math.MathContext) |
| 1812 | * @since 1.5 |
| 1813 | */ |
| 1814 | public BigDecimal[] divideAndRemainder(BigDecimal divisor) { |
| 1815 | // we use the identity x = i * y + r to determine r |
| 1816 | BigDecimal[] result = new BigDecimal[2]; |
| 1817 | |
| 1818 | result[0] = this.divideToIntegralValue(divisor); |
| 1819 | result[1] = this.subtract(result[0].multiply(divisor)); |
| 1820 | return result; |
| 1821 | } |
| 1822 | |
| 1823 | /** |
| 1824 | * Returns a two-element {@code BigDecimal} array containing the |
| 1825 | * result of {@code divideToIntegralValue} followed by the result of |
| 1826 | * {@code remainder} on the two operands calculated with rounding |
| 1827 | * according to the context settings. |
| 1828 | * |
| 1829 | * <p>Note that if both the integer quotient and remainder are |
| 1830 | * needed, this method is faster than using the |
| 1831 | * {@code divideToIntegralValue} and {@code remainder} methods |
| 1832 | * separately because the division need only be carried out once. |
| 1833 | * |
| 1834 | * @param divisor value by which this {@code BigDecimal} is to be divided, |
| 1835 | * and the remainder computed. |
| 1836 | * @param mc the context to use. |
| 1837 | * @return a two element {@code BigDecimal} array: the quotient |
| 1838 | * (the result of {@code divideToIntegralValue}) is the |
| 1839 | * initial element and the remainder is the final element. |
| 1840 | * @throws ArithmeticException if {@code divisor==0} |
| 1841 | * @throws ArithmeticException if the result is inexact but the |
| 1842 | * rounding mode is {@code UNNECESSARY}, or {@code mc.precision} |
| 1843 | * {@literal >} 0 and the result of {@code this.divideToIntgralValue(divisor)} would |
| 1844 | * require a precision of more than {@code mc.precision} digits. |
| 1845 | * @see #divideToIntegralValue(java.math.BigDecimal, java.math.MathContext) |
| 1846 | * @see #remainder(java.math.BigDecimal, java.math.MathContext) |
| 1847 | * @since 1.5 |
| 1848 | */ |
| 1849 | public BigDecimal[] divideAndRemainder(BigDecimal divisor, MathContext mc) { |
| 1850 | if (mc.precision == 0) |
| 1851 | return divideAndRemainder(divisor); |
| 1852 | |
| 1853 | BigDecimal[] result = new BigDecimal[2]; |
| 1854 | BigDecimal lhs = this; |
| 1855 | |
| 1856 | result[0] = lhs.divideToIntegralValue(divisor, mc); |
| 1857 | result[1] = lhs.subtract(result[0].multiply(divisor)); |
| 1858 | return result; |
| 1859 | } |
| 1860 | |
| 1861 | /** |
| 1862 | * Returns a {@code BigDecimal} whose value is |
| 1863 | * <tt>(this<sup>n</sup>)</tt>, The power is computed exactly, to |
| 1864 | * unlimited precision. |
| 1865 | * |
| 1866 | * <p>The parameter {@code n} must be in the range 0 through |
| 1867 | * 999999999, inclusive. {@code ZERO.pow(0)} returns {@link |
| 1868 | * #ONE}. |
| 1869 | * |
| 1870 | * Note that future releases may expand the allowable exponent |
| 1871 | * range of this method. |
| 1872 | * |
| 1873 | * @param n power to raise this {@code BigDecimal} to. |
| 1874 | * @return <tt>this<sup>n</sup></tt> |
| 1875 | * @throws ArithmeticException if {@code n} is out of range. |
| 1876 | * @since 1.5 |
| 1877 | */ |
| 1878 | public BigDecimal pow(int n) { |
| 1879 | if (n < 0 || n > 999999999) |
| 1880 | throw new ArithmeticException("Invalid operation"); |
| 1881 | // No need to calculate pow(n) if result will over/underflow. |
| 1882 | // Don't attempt to support "supernormal" numbers. |
| 1883 | int newScale = checkScale((long)scale * n); |
| 1884 | this.inflate(); |
| 1885 | return new BigDecimal(intVal.pow(n), newScale); |
| 1886 | } |
| 1887 | |
| 1888 | |
| 1889 | /** |
| 1890 | * Returns a {@code BigDecimal} whose value is |
| 1891 | * <tt>(this<sup>n</sup>)</tt>. The current implementation uses |
| 1892 | * the core algorithm defined in ANSI standard X3.274-1996 with |
| 1893 | * rounding according to the context settings. In general, the |
| 1894 | * returned numerical value is within two ulps of the exact |
| 1895 | * numerical value for the chosen precision. Note that future |
| 1896 | * releases may use a different algorithm with a decreased |
| 1897 | * allowable error bound and increased allowable exponent range. |
| 1898 | * |
| 1899 | * <p>The X3.274-1996 algorithm is: |
| 1900 | * |
| 1901 | * <ul> |
| 1902 | * <li> An {@code ArithmeticException} exception is thrown if |
| 1903 | * <ul> |
| 1904 | * <li>{@code abs(n) > 999999999} |
| 1905 | * <li>{@code mc.precision == 0} and {@code n < 0} |
| 1906 | * <li>{@code mc.precision > 0} and {@code n} has more than |
| 1907 | * {@code mc.precision} decimal digits |
| 1908 | * </ul> |
| 1909 | * |
| 1910 | * <li> if {@code n} is zero, {@link #ONE} is returned even if |
| 1911 | * {@code this} is zero, otherwise |
| 1912 | * <ul> |
| 1913 | * <li> if {@code n} is positive, the result is calculated via |
| 1914 | * the repeated squaring technique into a single accumulator. |
| 1915 | * The individual multiplications with the accumulator use the |
| 1916 | * same math context settings as in {@code mc} except for a |
| 1917 | * precision increased to {@code mc.precision + elength + 1} |
| 1918 | * where {@code elength} is the number of decimal digits in |
| 1919 | * {@code n}. |
| 1920 | * |
| 1921 | * <li> if {@code n} is negative, the result is calculated as if |
| 1922 | * {@code n} were positive; this value is then divided into one |
| 1923 | * using the working precision specified above. |
| 1924 | * |
| 1925 | * <li> The final value from either the positive or negative case |
| 1926 | * is then rounded to the destination precision. |
| 1927 | * </ul> |
| 1928 | * </ul> |
| 1929 | * |
| 1930 | * @param n power to raise this {@code BigDecimal} to. |
| 1931 | * @param mc the context to use. |
| 1932 | * @return <tt>this<sup>n</sup></tt> using the ANSI standard X3.274-1996 |
| 1933 | * algorithm |
| 1934 | * @throws ArithmeticException if the result is inexact but the |
| 1935 | * rounding mode is {@code UNNECESSARY}, or {@code n} is out |
| 1936 | * of range. |
| 1937 | * @since 1.5 |
| 1938 | */ |
| 1939 | public BigDecimal pow(int n, MathContext mc) { |
| 1940 | if (mc.precision == 0) |
| 1941 | return pow(n); |
| 1942 | if (n < -999999999 || n > 999999999) |
| 1943 | throw new ArithmeticException("Invalid operation"); |
| 1944 | if (n == 0) |
| 1945 | return ONE; // x**0 == 1 in X3.274 |
| 1946 | this.inflate(); |
| 1947 | BigDecimal lhs = this; |
| 1948 | MathContext workmc = mc; // working settings |
| 1949 | int mag = Math.abs(n); // magnitude of n |
| 1950 | if (mc.precision > 0) { |
| 1951 | |
| 1952 | int elength = intLength(mag); // length of n in digits |
| 1953 | if (elength > mc.precision) // X3.274 rule |
| 1954 | throw new ArithmeticException("Invalid operation"); |
| 1955 | workmc = new MathContext(mc.precision + elength + 1, |
| 1956 | mc.roundingMode); |
| 1957 | } |
| 1958 | // ready to carry out power calculation... |
| 1959 | BigDecimal acc = ONE; // accumulator |
| 1960 | boolean seenbit = false; // set once we've seen a 1-bit |
| 1961 | for (int i=1;;i++) { // for each bit [top bit ignored] |
| 1962 | mag += mag; // shift left 1 bit |
| 1963 | if (mag < 0) { // top bit is set |
| 1964 | seenbit = true; // OK, we're off |
| 1965 | acc = acc.multiply(lhs, workmc); // acc=acc*x |
| 1966 | } |
| 1967 | if (i == 31) |
| 1968 | break; // that was the last bit |
| 1969 | if (seenbit) |
| 1970 | acc=acc.multiply(acc, workmc); // acc=acc*acc [square] |
| 1971 | // else (!seenbit) no point in squaring ONE |
| 1972 | } |
| 1973 | // if negative n, calculate the reciprocal using working precision |
| 1974 | if (n<0) // [hence mc.precision>0] |
| 1975 | acc=ONE.divide(acc, workmc); |
| 1976 | // round to final precision and strip zeros |
| 1977 | return acc.doRound(mc); |
| 1978 | } |
| 1979 | |
| 1980 | /** |
| 1981 | * Returns a {@code BigDecimal} whose value is the absolute value |
| 1982 | * of this {@code BigDecimal}, and whose scale is |
| 1983 | * {@code this.scale()}. |
| 1984 | * |
| 1985 | * @return {@code abs(this)} |
| 1986 | */ |
| 1987 | public BigDecimal abs() { |
| 1988 | return (signum() < 0 ? negate() : this); |
| 1989 | } |
| 1990 | |
| 1991 | /** |
| 1992 | * Returns a {@code BigDecimal} whose value is the absolute value |
| 1993 | * of this {@code BigDecimal}, with rounding according to the |
| 1994 | * context settings. |
| 1995 | * |
| 1996 | * @param mc the context to use. |
| 1997 | * @return {@code abs(this)}, rounded as necessary. |
| 1998 | * @throws ArithmeticException if the result is inexact but the |
| 1999 | * rounding mode is {@code UNNECESSARY}. |
| 2000 | * @since 1.5 |
| 2001 | */ |
| 2002 | public BigDecimal abs(MathContext mc) { |
| 2003 | return (signum() < 0 ? negate(mc) : plus(mc)); |
| 2004 | } |
| 2005 | |
| 2006 | /** |
| 2007 | * Returns a {@code BigDecimal} whose value is {@code (-this)}, |
| 2008 | * and whose scale is {@code this.scale()}. |
| 2009 | * |
| 2010 | * @return {@code -this}. |
| 2011 | */ |
| 2012 | public BigDecimal negate() { |
| 2013 | BigDecimal result; |
| 2014 | if (intCompact != INFLATED) |
| 2015 | result = BigDecimal.valueOf(-intCompact, scale); |
| 2016 | else { |
| 2017 | result = new BigDecimal(intVal.negate(), scale); |
| 2018 | result.precision = precision; |
| 2019 | } |
| 2020 | return result; |
| 2021 | } |
| 2022 | |
| 2023 | /** |
| 2024 | * Returns a {@code BigDecimal} whose value is {@code (-this)}, |
| 2025 | * with rounding according to the context settings. |
| 2026 | * |
| 2027 | * @param mc the context to use. |
| 2028 | * @return {@code -this}, rounded as necessary. |
| 2029 | * @throws ArithmeticException if the result is inexact but the |
| 2030 | * rounding mode is {@code UNNECESSARY}. |
| 2031 | * @since 1.5 |
| 2032 | */ |
| 2033 | public BigDecimal negate(MathContext mc) { |
| 2034 | return negate().plus(mc); |
| 2035 | } |
| 2036 | |
| 2037 | /** |
| 2038 | * Returns a {@code BigDecimal} whose value is {@code (+this)}, and whose |
| 2039 | * scale is {@code this.scale()}. |
| 2040 | * |
| 2041 | * <p>This method, which simply returns this {@code BigDecimal} |
| 2042 | * is included for symmetry with the unary minus method {@link |
| 2043 | * #negate()}. |
| 2044 | * |
| 2045 | * @return {@code this}. |
| 2046 | * @see #negate() |
| 2047 | * @since 1.5 |
| 2048 | */ |
| 2049 | public BigDecimal plus() { |
| 2050 | return this; |
| 2051 | } |
| 2052 | |
| 2053 | /** |
| 2054 | * Returns a {@code BigDecimal} whose value is {@code (+this)}, |
| 2055 | * with rounding according to the context settings. |
| 2056 | * |
| 2057 | * <p>The effect of this method is identical to that of the {@link |
| 2058 | * #round(MathContext)} method. |
| 2059 | * |
| 2060 | * @param mc the context to use. |
| 2061 | * @return {@code this}, rounded as necessary. A zero result will |
| 2062 | * have a scale of 0. |
| 2063 | * @throws ArithmeticException if the result is inexact but the |
| 2064 | * rounding mode is {@code UNNECESSARY}. |
| 2065 | * @see #round(MathContext) |
| 2066 | * @since 1.5 |
| 2067 | */ |
| 2068 | public BigDecimal plus(MathContext mc) { |
| 2069 | if (mc.precision == 0) // no rounding please |
| 2070 | return this; |
| 2071 | return this.doRound(mc); |
| 2072 | } |
| 2073 | |
| 2074 | /** |
| 2075 | * Returns the signum function of this {@code BigDecimal}. |
| 2076 | * |
| 2077 | * @return -1, 0, or 1 as the value of this {@code BigDecimal} |
| 2078 | * is negative, zero, or positive. |
| 2079 | */ |
| 2080 | public int signum() { |
| 2081 | return (intCompact != INFLATED)? |
| 2082 | Long.signum(intCompact): |
| 2083 | intVal.signum(); |
| 2084 | } |
| 2085 | |
| 2086 | /** |
| 2087 | * Returns the <i>scale</i> of this {@code BigDecimal}. If zero |
| 2088 | * or positive, the scale is the number of digits to the right of |
| 2089 | * the decimal point. If negative, the unscaled value of the |
| 2090 | * number is multiplied by ten to the power of the negation of the |
| 2091 | * scale. For example, a scale of {@code -3} means the unscaled |
| 2092 | * value is multiplied by 1000. |
| 2093 | * |
| 2094 | * @return the scale of this {@code BigDecimal}. |
| 2095 | */ |
| 2096 | public int scale() { |
| 2097 | return scale; |
| 2098 | } |
| 2099 | |
| 2100 | /** |
| 2101 | * Returns the <i>precision</i> of this {@code BigDecimal}. (The |
| 2102 | * precision is the number of digits in the unscaled value.) |
| 2103 | * |
| 2104 | * <p>The precision of a zero value is 1. |
| 2105 | * |
| 2106 | * @return the precision of this {@code BigDecimal}. |
| 2107 | * @since 1.5 |
| 2108 | */ |
| 2109 | public int precision() { |
| 2110 | int result = precision; |
| 2111 | if (result == 0) { |
| 2112 | result = digitLength(); |
| 2113 | precision = result; |
| 2114 | } |
| 2115 | return result; |
| 2116 | } |
| 2117 | |
| 2118 | |
| 2119 | /** |
| 2120 | * Returns a {@code BigInteger} whose value is the <i>unscaled |
| 2121 | * value</i> of this {@code BigDecimal}. (Computes <tt>(this * |
| 2122 | * 10<sup>this.scale()</sup>)</tt>.) |
| 2123 | * |
| 2124 | * @return the unscaled value of this {@code BigDecimal}. |
| 2125 | * @since 1.2 |
| 2126 | */ |
| 2127 | public BigInteger unscaledValue() { |
| 2128 | return this.inflate().intVal; |
| 2129 | } |
| 2130 | |
| 2131 | // Rounding Modes |
| 2132 | |
| 2133 | /** |
| 2134 | * Rounding mode to round away from zero. Always increments the |
| 2135 | * digit prior to a nonzero discarded fraction. Note that this rounding |
| 2136 | * mode never decreases the magnitude of the calculated value. |
| 2137 | */ |
| 2138 | public final static int ROUND_UP = 0; |
| 2139 | |
| 2140 | /** |
| 2141 | * Rounding mode to round towards zero. Never increments the digit |
| 2142 | * prior to a discarded fraction (i.e., truncates). Note that this |
| 2143 | * rounding mode never increases the magnitude of the calculated value. |
| 2144 | */ |
| 2145 | public final static int ROUND_DOWN = 1; |
| 2146 | |
| 2147 | /** |
| 2148 | * Rounding mode to round towards positive infinity. If the |
| 2149 | * {@code BigDecimal} is positive, behaves as for |
| 2150 | * {@code ROUND_UP}; if negative, behaves as for |
| 2151 | * {@code ROUND_DOWN}. Note that this rounding mode never |
| 2152 | * decreases the calculated value. |
| 2153 | */ |
| 2154 | public final static int ROUND_CEILING = 2; |
| 2155 | |
| 2156 | /** |
| 2157 | * Rounding mode to round towards negative infinity. If the |
| 2158 | * {@code BigDecimal} is positive, behave as for |
| 2159 | * {@code ROUND_DOWN}; if negative, behave as for |
| 2160 | * {@code ROUND_UP}. Note that this rounding mode never |
| 2161 | * increases the calculated value. |
| 2162 | */ |
| 2163 | public final static int ROUND_FLOOR = 3; |
| 2164 | |
| 2165 | /** |
| 2166 | * Rounding mode to round towards {@literal "nearest neighbor"} |
| 2167 | * unless both neighbors are equidistant, in which case round up. |
| 2168 | * Behaves as for {@code ROUND_UP} if the discarded fraction is |
| 2169 | * ≥ 0.5; otherwise, behaves as for {@code ROUND_DOWN}. Note |
| 2170 | * that this is the rounding mode that most of us were taught in |
| 2171 | * grade school. |
| 2172 | */ |
| 2173 | public final static int ROUND_HALF_UP = 4; |
| 2174 | |
| 2175 | /** |
| 2176 | * Rounding mode to round towards {@literal "nearest neighbor"} |
| 2177 | * unless both neighbors are equidistant, in which case round |
| 2178 | * down. Behaves as for {@code ROUND_UP} if the discarded |
| 2179 | * fraction is {@literal >} 0.5; otherwise, behaves as for |
| 2180 | * {@code ROUND_DOWN}. |
| 2181 | */ |
| 2182 | public final static int ROUND_HALF_DOWN = 5; |
| 2183 | |
| 2184 | /** |
| 2185 | * Rounding mode to round towards the {@literal "nearest neighbor"} |
| 2186 | * unless both neighbors are equidistant, in which case, round |
| 2187 | * towards the even neighbor. Behaves as for |
| 2188 | * {@code ROUND_HALF_UP} if the digit to the left of the |
| 2189 | * discarded fraction is odd; behaves as for |
| 2190 | * {@code ROUND_HALF_DOWN} if it's even. Note that this is the |
| 2191 | * rounding mode that minimizes cumulative error when applied |
| 2192 | * repeatedly over a sequence of calculations. |
| 2193 | */ |
| 2194 | public final static int ROUND_HALF_EVEN = 6; |
| 2195 | |
| 2196 | /** |
| 2197 | * Rounding mode to assert that the requested operation has an exact |
| 2198 | * result, hence no rounding is necessary. If this rounding mode is |
| 2199 | * specified on an operation that yields an inexact result, an |
| 2200 | * {@code ArithmeticException} is thrown. |
| 2201 | */ |
| 2202 | public final static int ROUND_UNNECESSARY = 7; |
| 2203 | |
| 2204 | |
| 2205 | // Scaling/Rounding Operations |
| 2206 | |
| 2207 | /** |
| 2208 | * Returns a {@code BigDecimal} rounded according to the |
| 2209 | * {@code MathContext} settings. If the precision setting is 0 then |
| 2210 | * no rounding takes place. |
| 2211 | * |
| 2212 | * <p>The effect of this method is identical to that of the |
| 2213 | * {@link #plus(MathContext)} method. |
| 2214 | * |
| 2215 | * @param mc the context to use. |
| 2216 | * @return a {@code BigDecimal} rounded according to the |
| 2217 | * {@code MathContext} settings. |
| 2218 | * @throws ArithmeticException if the rounding mode is |
| 2219 | * {@code UNNECESSARY} and the |
| 2220 | * {@code BigDecimal} operation would require rounding. |
| 2221 | * @see #plus(MathContext) |
| 2222 | * @since 1.5 |
| 2223 | */ |
| 2224 | public BigDecimal round(MathContext mc) { |
| 2225 | return plus(mc); |
| 2226 | } |
| 2227 | |
| 2228 | /** |
| 2229 | * Returns a {@code BigDecimal} whose scale is the specified |
| 2230 | * value, and whose unscaled value is determined by multiplying or |
| 2231 | * dividing this {@code BigDecimal}'s unscaled value by the |
| 2232 | * appropriate power of ten to maintain its overall value. If the |
| 2233 | * scale is reduced by the operation, the unscaled value must be |
| 2234 | * divided (rather than multiplied), and the value may be changed; |
| 2235 | * in this case, the specified rounding mode is applied to the |
| 2236 | * division. |
| 2237 | * |
| 2238 | * <p>Note that since BigDecimal objects are immutable, calls of |
| 2239 | * this method do <i>not</i> result in the original object being |
| 2240 | * modified, contrary to the usual convention of having methods |
| 2241 | * named <tt>set<i>X</i></tt> mutate field <i>{@code X}</i>. |
| 2242 | * Instead, {@code setScale} returns an object with the proper |
| 2243 | * scale; the returned object may or may not be newly allocated. |
| 2244 | * |
| 2245 | * @param newScale scale of the {@code BigDecimal} value to be returned. |
| 2246 | * @param roundingMode The rounding mode to apply. |
| 2247 | * @return a {@code BigDecimal} whose scale is the specified value, |
| 2248 | * and whose unscaled value is determined by multiplying or |
| 2249 | * dividing this {@code BigDecimal}'s unscaled value by the |
| 2250 | * appropriate power of ten to maintain its overall value. |
| 2251 | * @throws ArithmeticException if {@code roundingMode==UNNECESSARY} |
| 2252 | * and the specified scaling operation would require |
| 2253 | * rounding. |
| 2254 | * @see RoundingMode |
| 2255 | * @since 1.5 |
| 2256 | */ |
| 2257 | public BigDecimal setScale(int newScale, RoundingMode roundingMode) { |
| 2258 | return setScale(newScale, roundingMode.oldMode); |
| 2259 | } |
| 2260 | |
| 2261 | /** |
| 2262 | * Returns a {@code BigDecimal} whose scale is the specified |
| 2263 | * value, and whose unscaled value is determined by multiplying or |
| 2264 | * dividing this {@code BigDecimal}'s unscaled value by the |
| 2265 | * appropriate power of ten to maintain its overall value. If the |
| 2266 | * scale is reduced by the operation, the unscaled value must be |
| 2267 | * divided (rather than multiplied), and the value may be changed; |
| 2268 | * in this case, the specified rounding mode is applied to the |
| 2269 | * division. |
| 2270 | * |
| 2271 | * <p>Note that since BigDecimal objects are immutable, calls of |
| 2272 | * this method do <i>not</i> result in the original object being |
| 2273 | * modified, contrary to the usual convention of having methods |
| 2274 | * named <tt>set<i>X</i></tt> mutate field <i>{@code X}</i>. |
| 2275 | * Instead, {@code setScale} returns an object with the proper |
| 2276 | * scale; the returned object may or may not be newly allocated. |
| 2277 | * |
| 2278 | * <p>The new {@link #setScale(int, RoundingMode)} method should |
| 2279 | * be used in preference to this legacy method. |
| 2280 | * |
| 2281 | * @param newScale scale of the {@code BigDecimal} value to be returned. |
| 2282 | * @param roundingMode The rounding mode to apply. |
| 2283 | * @return a {@code BigDecimal} whose scale is the specified value, |
| 2284 | * and whose unscaled value is determined by multiplying or |
| 2285 | * dividing this {@code BigDecimal}'s unscaled value by the |
| 2286 | * appropriate power of ten to maintain its overall value. |
| 2287 | * @throws ArithmeticException if {@code roundingMode==ROUND_UNNECESSARY} |
| 2288 | * and the specified scaling operation would require |
| 2289 | * rounding. |
| 2290 | * @throws IllegalArgumentException if {@code roundingMode} does not |
| 2291 | * represent a valid rounding mode. |
| 2292 | * @see #ROUND_UP |
| 2293 | * @see #ROUND_DOWN |
| 2294 | * @see #ROUND_CEILING |
| 2295 | * @see #ROUND_FLOOR |
| 2296 | * @see #ROUND_HALF_UP |
| 2297 | * @see #ROUND_HALF_DOWN |
| 2298 | * @see #ROUND_HALF_EVEN |
| 2299 | * @see #ROUND_UNNECESSARY |
| 2300 | */ |
| 2301 | public BigDecimal setScale(int newScale, int roundingMode) { |
| 2302 | if (roundingMode < ROUND_UP || roundingMode > ROUND_UNNECESSARY) |
| 2303 | throw new IllegalArgumentException("Invalid rounding mode"); |
| 2304 | |
| 2305 | if (newScale == this.scale) // easy case |
| 2306 | return this; |
| 2307 | if (this.signum() == 0) // zero can have any scale |
| 2308 | return BigDecimal.valueOf(0, newScale); |
| 2309 | if (newScale > this.scale) { |
| 2310 | // [we can use checkScale to assure multiplier is valid] |
| 2311 | int raise = checkScale((long)newScale - this.scale); |
| 2312 | |
| 2313 | if (intCompact != INFLATED) { |
| 2314 | long scaledResult = longTenToThe(intCompact, raise); |
| 2315 | if (scaledResult != INFLATED) |
| 2316 | return BigDecimal.valueOf(scaledResult, newScale); |
| 2317 | this.inflate(); |
| 2318 | } |
| 2319 | |
| 2320 | BigDecimal result = new BigDecimal(intVal.multiply(tenToThe(raise)), |
| 2321 | newScale); |
| 2322 | if (this.precision > 0) |
| 2323 | result.precision = this.precision + newScale - this.scale; |
| 2324 | return result; |
| 2325 | } |
| 2326 | // scale < this.scale |
| 2327 | // we cannot perfectly predict the precision after rounding |
| 2328 | return divide(ONE, newScale, roundingMode); |
| 2329 | } |
| 2330 | |
| 2331 | /** |
| 2332 | * Returns a {@code BigDecimal} whose scale is the specified |
| 2333 | * value, and whose value is numerically equal to this |
| 2334 | * {@code BigDecimal}'s. Throws an {@code ArithmeticException} |
| 2335 | * if this is not possible. |
| 2336 | * |
| 2337 | * <p>This call is typically used to increase the scale, in which |
| 2338 | * case it is guaranteed that there exists a {@code BigDecimal} |
| 2339 | * of the specified scale and the correct value. The call can |
| 2340 | * also be used to reduce the scale if the caller knows that the |
| 2341 | * {@code BigDecimal} has sufficiently many zeros at the end of |
| 2342 | * its fractional part (i.e., factors of ten in its integer value) |
| 2343 | * to allow for the rescaling without changing its value. |
| 2344 | * |
| 2345 | * <p>This method returns the same result as the two-argument |
| 2346 | * versions of {@code setScale}, but saves the caller the trouble |
| 2347 | * of specifying a rounding mode in cases where it is irrelevant. |
| 2348 | * |
| 2349 | * <p>Note that since {@code BigDecimal} objects are immutable, |
| 2350 | * calls of this method do <i>not</i> result in the original |
| 2351 | * object being modified, contrary to the usual convention of |
| 2352 | * having methods named <tt>set<i>X</i></tt> mutate field |
| 2353 | * <i>{@code X}</i>. Instead, {@code setScale} returns an |
| 2354 | * object with the proper scale; the returned object may or may |
| 2355 | * not be newly allocated. |
| 2356 | * |
| 2357 | * @param newScale scale of the {@code BigDecimal} value to be returned. |
| 2358 | * @return a {@code BigDecimal} whose scale is the specified value, and |
| 2359 | * whose unscaled value is determined by multiplying or dividing |
| 2360 | * this {@code BigDecimal}'s unscaled value by the appropriate |
| 2361 | * power of ten to maintain its overall value. |
| 2362 | * @throws ArithmeticException if the specified scaling operation would |
| 2363 | * require rounding. |
| 2364 | * @see #setScale(int, int) |
| 2365 | * @see #setScale(int, RoundingMode) |
| 2366 | */ |
| 2367 | public BigDecimal setScale(int newScale) { |
| 2368 | return setScale(newScale, ROUND_UNNECESSARY); |
| 2369 | } |
| 2370 | |
| 2371 | // Decimal Point Motion Operations |
| 2372 | |
| 2373 | /** |
| 2374 | * Returns a {@code BigDecimal} which is equivalent to this one |
| 2375 | * with the decimal point moved {@code n} places to the left. If |
| 2376 | * {@code n} is non-negative, the call merely adds {@code n} to |
| 2377 | * the scale. If {@code n} is negative, the call is equivalent |
| 2378 | * to {@code movePointRight(-n)}. The {@code BigDecimal} |
| 2379 | * returned by this call has value <tt>(this × |
| 2380 | * 10<sup>-n</sup>)</tt> and scale {@code max(this.scale()+n, |
| 2381 | * 0)}. |
| 2382 | * |
| 2383 | * @param n number of places to move the decimal point to the left. |
| 2384 | * @return a {@code BigDecimal} which is equivalent to this one with the |
| 2385 | * decimal point moved {@code n} places to the left. |
| 2386 | * @throws ArithmeticException if scale overflows. |
| 2387 | */ |
| 2388 | public BigDecimal movePointLeft(int n) { |
| 2389 | // Cannot use movePointRight(-n) in case of n==Integer.MIN_VALUE |
| 2390 | int newScale = checkScale((long)scale + n); |
| 2391 | BigDecimal num; |
| 2392 | if (intCompact != INFLATED) |
| 2393 | num = BigDecimal.valueOf(intCompact, newScale); |
| 2394 | else |
| 2395 | num = new BigDecimal(intVal, newScale); |
| 2396 | return (num.scale<0 ? num.setScale(0) : num); |
| 2397 | } |
| 2398 | |
| 2399 | /** |
| 2400 | * Returns a {@code BigDecimal} which is equivalent to this one |
| 2401 | * with the decimal point moved {@code n} places to the right. |
| 2402 | * If {@code n} is non-negative, the call merely subtracts |
| 2403 | * {@code n} from the scale. If {@code n} is negative, the call |
| 2404 | * is equivalent to {@code movePointLeft(-n)}. The |
| 2405 | * {@code BigDecimal} returned by this call has value <tt>(this |
| 2406 | * × 10<sup>n</sup>)</tt> and scale {@code max(this.scale()-n, |
| 2407 | * 0)}. |
| 2408 | * |
| 2409 | * @param n number of places to move the decimal point to the right. |
| 2410 | * @return a {@code BigDecimal} which is equivalent to this one |
| 2411 | * with the decimal point moved {@code n} places to the right. |
| 2412 | * @throws ArithmeticException if scale overflows. |
| 2413 | */ |
| 2414 | public BigDecimal movePointRight(int n) { |
| 2415 | // Cannot use movePointLeft(-n) in case of n==Integer.MIN_VALUE |
| 2416 | int newScale = checkScale((long)scale - n); |
| 2417 | BigDecimal num; |
| 2418 | if (intCompact != INFLATED) |
| 2419 | num = BigDecimal.valueOf(intCompact, newScale); |
| 2420 | else |
| 2421 | num = new BigDecimal(intVal, newScale); |
| 2422 | return (num.scale<0 ? num.setScale(0) : num); |
| 2423 | } |
| 2424 | |
| 2425 | /** |
| 2426 | * Returns a BigDecimal whose numerical value is equal to |
| 2427 | * ({@code this} * 10<sup>n</sup>). The scale of |
| 2428 | * the result is {@code (this.scale() - n)}. |
| 2429 | * |
| 2430 | * @throws ArithmeticException if the scale would be |
| 2431 | * outside the range of a 32-bit integer. |
| 2432 | * |
| 2433 | * @since 1.5 |
| 2434 | */ |
| 2435 | public BigDecimal scaleByPowerOfTen(int n) { |
| 2436 | this.inflate(); |
| 2437 | BigDecimal num = new BigDecimal(intVal, checkScale((long)scale - n)); |
| 2438 | num.precision = precision; |
| 2439 | return num; |
| 2440 | } |
| 2441 | |
| 2442 | /** |
| 2443 | * Returns a {@code BigDecimal} which is numerically equal to |
| 2444 | * this one but with any trailing zeros removed from the |
| 2445 | * representation. For example, stripping the trailing zeros from |
| 2446 | * the {@code BigDecimal} value {@code 600.0}, which has |
| 2447 | * [{@code BigInteger}, {@code scale}] components equals to |
| 2448 | * [6000, 1], yields {@code 6E2} with [{@code BigInteger}, |
| 2449 | * {@code scale}] components equals to [6, -2] |
| 2450 | * |
| 2451 | * @return a numerically equal {@code BigDecimal} with any |
| 2452 | * trailing zeros removed. |
| 2453 | * @since 1.5 |
| 2454 | */ |
| 2455 | public BigDecimal stripTrailingZeros() { |
| 2456 | this.inflate(); |
| 2457 | return (new BigDecimal(intVal, scale)).stripZerosToMatchScale(Long.MIN_VALUE); |
| 2458 | } |
| 2459 | |
| 2460 | // Comparison Operations |
| 2461 | |
| 2462 | /** |
| 2463 | * Compares this {@code BigDecimal} with the specified |
| 2464 | * {@code BigDecimal}. Two {@code BigDecimal} objects that are |
| 2465 | * equal in value but have a different scale (like 2.0 and 2.00) |
| 2466 | * are considered equal by this method. This method is provided |
| 2467 | * in preference to individual methods for each of the six boolean |
| 2468 | * comparison operators ({@literal <}, ==, |
| 2469 | * {@literal >}, {@literal >=}, !=, {@literal <=}). The |
| 2470 | * suggested idiom for performing these comparisons is: |
| 2471 | * {@code (x.compareTo(y)} <<i>op</i>> {@code 0)}, where |
| 2472 | * <<i>op</i>> is one of the six comparison operators. |
| 2473 | * |
| 2474 | * @param val {@code BigDecimal} to which this {@code BigDecimal} is |
| 2475 | * to be compared. |
| 2476 | * @return -1, 0, or 1 as this {@code BigDecimal} is numerically |
| 2477 | * less than, equal to, or greater than {@code val}. |
| 2478 | */ |
| 2479 | public int compareTo(BigDecimal val) { |
| 2480 | if (this.scale == val.scale && |
| 2481 | this.intCompact != INFLATED && |
| 2482 | val.intCompact != INFLATED) |
| 2483 | return longCompareTo(this.intCompact, val.intCompact); |
| 2484 | |
| 2485 | // Optimization: would run fine without the next three lines |
| 2486 | int sigDiff = signum() - val.signum(); |
| 2487 | if (sigDiff != 0) |
| 2488 | return (sigDiff > 0 ? 1 : -1); |
| 2489 | |
| 2490 | // If the (adjusted) exponents are different we do not need to |
| 2491 | // expensively match scales and compare the significands |
| 2492 | int aethis = this.precision() - this.scale; // [-1] |
| 2493 | int aeval = val.precision() - val.scale; // [-1] |
| 2494 | if (aethis < aeval) |
| 2495 | return -this.signum(); |
| 2496 | else if (aethis > aeval) |
| 2497 | return this.signum(); |
| 2498 | |
| 2499 | // Scale and compare intVals |
| 2500 | BigDecimal arg[] = {this, val}; |
| 2501 | matchScale(arg); |
| 2502 | if (arg[0].intCompact != INFLATED && |
| 2503 | arg[1].intCompact != INFLATED) |
| 2504 | return longCompareTo(arg[0].intCompact, arg[1].intCompact); |
| 2505 | return arg[0].inflate().intVal.compareTo(arg[1].inflate().intVal); |
| 2506 | } |
| 2507 | |
| 2508 | /** |
| 2509 | * Compares this {@code BigDecimal} with the specified |
| 2510 | * {@code Object} for equality. Unlike {@link |
| 2511 | * #compareTo(BigDecimal) compareTo}, this method considers two |
| 2512 | * {@code BigDecimal} objects equal only if they are equal in |
| 2513 | * value and scale (thus 2.0 is not equal to 2.00 when compared by |
| 2514 | * this method). |
| 2515 | * |
| 2516 | * @param x {@code Object} to which this {@code BigDecimal} is |
| 2517 | * to be compared. |
| 2518 | * @return {@code true} if and only if the specified {@code Object} is a |
| 2519 | * {@code BigDecimal} whose value and scale are equal to this |
| 2520 | * {@code BigDecimal}'s. |
| 2521 | * @see #compareTo(java.math.BigDecimal) |
| 2522 | * @see #hashCode |
| 2523 | */ |
| 2524 | public boolean equals(Object x) { |
| 2525 | if (!(x instanceof BigDecimal)) |
| 2526 | return false; |
| 2527 | BigDecimal xDec = (BigDecimal) x; |
| 2528 | if (scale != xDec.scale) |
| 2529 | return false; |
| 2530 | if (this.intCompact != INFLATED && xDec.intCompact != INFLATED) |
| 2531 | return this.intCompact == xDec.intCompact; |
| 2532 | return this.inflate().intVal.equals(xDec.inflate().intVal); |
| 2533 | } |
| 2534 | |
| 2535 | /** |
| 2536 | * Returns the minimum of this {@code BigDecimal} and |
| 2537 | * {@code val}. |
| 2538 | * |
| 2539 | * @param val value with which the minimum is to be computed. |
| 2540 | * @return the {@code BigDecimal} whose value is the lesser of this |
| 2541 | * {@code BigDecimal} and {@code val}. If they are equal, |
| 2542 | * as defined by the {@link #compareTo(BigDecimal) compareTo} |
| 2543 | * method, {@code this} is returned. |
| 2544 | * @see #compareTo(java.math.BigDecimal) |
| 2545 | */ |
| 2546 | public BigDecimal min(BigDecimal val) { |
| 2547 | return (compareTo(val) <= 0 ? this : val); |
| 2548 | } |
| 2549 | |
| 2550 | /** |
| 2551 | * Returns the maximum of this {@code BigDecimal} and {@code val}. |
| 2552 | * |
| 2553 | * @param val value with which the maximum is to be computed. |
| 2554 | * @return the {@code BigDecimal} whose value is the greater of this |
| 2555 | * {@code BigDecimal} and {@code val}. If they are equal, |
| 2556 | * as defined by the {@link #compareTo(BigDecimal) compareTo} |
| 2557 | * method, {@code this} is returned. |
| 2558 | * @see #compareTo(java.math.BigDecimal) |
| 2559 | */ |
| 2560 | public BigDecimal max(BigDecimal val) { |
| 2561 | return (compareTo(val) >= 0 ? this : val); |
| 2562 | } |
| 2563 | |
| 2564 | // Hash Function |
| 2565 | |
| 2566 | /** |
| 2567 | * Returns the hash code for this {@code BigDecimal}. Note that |
| 2568 | * two {@code BigDecimal} objects that are numerically equal but |
| 2569 | * differ in scale (like 2.0 and 2.00) will generally <i>not</i> |
| 2570 | * have the same hash code. |
| 2571 | * |
| 2572 | * @return hash code for this {@code BigDecimal}. |
| 2573 | * @see #equals(Object) |
| 2574 | */ |
| 2575 | public int hashCode() { |
| 2576 | if (intCompact != INFLATED) { |
| 2577 | long val2 = (intCompact < 0)?-intCompact:intCompact; |
| 2578 | int temp = (int)( ((int)(val2 >>> 32)) * 31 + |
| 2579 | (val2 & 0xffffffffL)); |
| 2580 | return 31*((intCompact < 0) ?-temp:temp) + scale; |
| 2581 | } else |
| 2582 | return 31*intVal.hashCode() + scale; |
| 2583 | } |
| 2584 | |
| 2585 | // Format Converters |
| 2586 | |
| 2587 | /** |
| 2588 | * Returns the string representation of this {@code BigDecimal}, |
| 2589 | * using scientific notation if an exponent is needed. |
| 2590 | * |
| 2591 | * <p>A standard canonical string form of the {@code BigDecimal} |
| 2592 | * is created as though by the following steps: first, the |
| 2593 | * absolute value of the unscaled value of the {@code BigDecimal} |
| 2594 | * is converted to a string in base ten using the characters |
| 2595 | * {@code '0'} through {@code '9'} with no leading zeros (except |
| 2596 | * if its value is zero, in which case a single {@code '0'} |
| 2597 | * character is used). |
| 2598 | * |
| 2599 | * <p>Next, an <i>adjusted exponent</i> is calculated; this is the |
| 2600 | * negated scale, plus the number of characters in the converted |
| 2601 | * unscaled value, less one. That is, |
| 2602 | * {@code -scale+(ulength-1)}, where {@code ulength} is the |
| 2603 | * length of the absolute value of the unscaled value in decimal |
| 2604 | * digits (its <i>precision</i>). |
| 2605 | * |
| 2606 | * <p>If the scale is greater than or equal to zero and the |
| 2607 | * adjusted exponent is greater than or equal to {@code -6}, the |
| 2608 | * number will be converted to a character form without using |
| 2609 | * exponential notation. In this case, if the scale is zero then |
| 2610 | * no decimal point is added and if the scale is positive a |
| 2611 | * decimal point will be inserted with the scale specifying the |
| 2612 | * number of characters to the right of the decimal point. |
| 2613 | * {@code '0'} characters are added to the left of the converted |
| 2614 | * unscaled value as necessary. If no character precedes the |
| 2615 | * decimal point after this insertion then a conventional |
| 2616 | * {@code '0'} character is prefixed. |
| 2617 | * |
| 2618 | * <p>Otherwise (that is, if the scale is negative, or the |
| 2619 | * adjusted exponent is less than {@code -6}), the number will be |
| 2620 | * converted to a character form using exponential notation. In |
| 2621 | * this case, if the converted {@code BigInteger} has more than |
| 2622 | * one digit a decimal point is inserted after the first digit. |
| 2623 | * An exponent in character form is then suffixed to the converted |
| 2624 | * unscaled value (perhaps with inserted decimal point); this |
| 2625 | * comprises the letter {@code 'E'} followed immediately by the |
| 2626 | * adjusted exponent converted to a character form. The latter is |
| 2627 | * in base ten, using the characters {@code '0'} through |
| 2628 | * {@code '9'} with no leading zeros, and is always prefixed by a |
| 2629 | * sign character {@code '-'} (<tt>'\u002D'</tt>) if the |
| 2630 | * adjusted exponent is negative, {@code '+'} |
| 2631 | * (<tt>'\u002B'</tt>) otherwise). |
| 2632 | * |
| 2633 | * <p>Finally, the entire string is prefixed by a minus sign |
| 2634 | * character {@code '-'} (<tt>'\u002D'</tt>) if the unscaled |
| 2635 | * value is less than zero. No sign character is prefixed if the |
| 2636 | * unscaled value is zero or positive. |
| 2637 | * |
| 2638 | * <p><b>Examples:</b> |
| 2639 | * <p>For each representation [<i>unscaled value</i>, <i>scale</i>] |
| 2640 | * on the left, the resulting string is shown on the right. |
| 2641 | * <pre> |
| 2642 | * [123,0] "123" |
| 2643 | * [-123,0] "-123" |
| 2644 | * [123,-1] "1.23E+3" |
| 2645 | * [123,-3] "1.23E+5" |
| 2646 | * [123,1] "12.3" |
| 2647 | * [123,5] "0.00123" |
| 2648 | * [123,10] "1.23E-8" |
| 2649 | * [-123,12] "-1.23E-10" |
| 2650 | * </pre> |
| 2651 | * |
| 2652 | * <b>Notes:</b> |
| 2653 | * <ol> |
| 2654 | * |
| 2655 | * <li>There is a one-to-one mapping between the distinguishable |
| 2656 | * {@code BigDecimal} values and the result of this conversion. |
| 2657 | * That is, every distinguishable {@code BigDecimal} value |
| 2658 | * (unscaled value and scale) has a unique string representation |
| 2659 | * as a result of using {@code toString}. If that string |
| 2660 | * representation is converted back to a {@code BigDecimal} using |
| 2661 | * the {@link #BigDecimal(String)} constructor, then the original |
| 2662 | * value will be recovered. |
| 2663 | * |
| 2664 | * <li>The string produced for a given number is always the same; |
| 2665 | * it is not affected by locale. This means that it can be used |
| 2666 | * as a canonical string representation for exchanging decimal |
| 2667 | * data, or as a key for a Hashtable, etc. Locale-sensitive |
| 2668 | * number formatting and parsing is handled by the {@link |
| 2669 | * java.text.NumberFormat} class and its subclasses. |
| 2670 | * |
| 2671 | * <li>The {@link #toEngineeringString} method may be used for |
| 2672 | * presenting numbers with exponents in engineering notation, and the |
| 2673 | * {@link #setScale(int,RoundingMode) setScale} method may be used for |
| 2674 | * rounding a {@code BigDecimal} so it has a known number of digits after |
| 2675 | * the decimal point. |
| 2676 | * |
| 2677 | * <li>The digit-to-character mapping provided by |
| 2678 | * {@code Character.forDigit} is used. |
| 2679 | * |
| 2680 | * </ol> |
| 2681 | * |
| 2682 | * @return string representation of this {@code BigDecimal}. |
| 2683 | * @see Character#forDigit |
| 2684 | * @see #BigDecimal(java.lang.String) |
| 2685 | */ |
| 2686 | public String toString() { |
| 2687 | if (stringCache == null) |
| 2688 | stringCache = layoutChars(true); |
| 2689 | return stringCache; |
| 2690 | } |
| 2691 | |
| 2692 | /** |
| 2693 | * Returns a string representation of this {@code BigDecimal}, |
| 2694 | * using engineering notation if an exponent is needed. |
| 2695 | * |
| 2696 | * <p>Returns a string that represents the {@code BigDecimal} as |
| 2697 | * described in the {@link #toString()} method, except that if |
| 2698 | * exponential notation is used, the power of ten is adjusted to |
| 2699 | * be a multiple of three (engineering notation) such that the |
| 2700 | * integer part of nonzero values will be in the range 1 through |
| 2701 | * 999. If exponential notation is used for zero values, a |
| 2702 | * decimal point and one or two fractional zero digits are used so |
| 2703 | * that the scale of the zero value is preserved. Note that |
| 2704 | * unlike the output of {@link #toString()}, the output of this |
| 2705 | * method is <em>not</em> guaranteed to recover the same [integer, |
| 2706 | * scale] pair of this {@code BigDecimal} if the output string is |
| 2707 | * converting back to a {@code BigDecimal} using the {@linkplain |
| 2708 | * #BigDecimal(String) string constructor}. The result of this method meets |
| 2709 | * the weaker constraint of always producing a numerically equal |
| 2710 | * result from applying the string constructor to the method's output. |
| 2711 | * |
| 2712 | * @return string representation of this {@code BigDecimal}, using |
| 2713 | * engineering notation if an exponent is needed. |
| 2714 | * @since 1.5 |
| 2715 | */ |
| 2716 | public String toEngineeringString() { |
| 2717 | return layoutChars(false); |
| 2718 | } |
| 2719 | |
| 2720 | /** |
| 2721 | * Returns a string representation of this {@code BigDecimal} |
| 2722 | * without an exponent field. For values with a positive scale, |
| 2723 | * the number of digits to the right of the decimal point is used |
| 2724 | * to indicate scale. For values with a zero or negative scale, |
| 2725 | * the resulting string is generated as if the value were |
| 2726 | * converted to a numerically equal value with zero scale and as |
| 2727 | * if all the trailing zeros of the zero scale value were present |
| 2728 | * in the result. |
| 2729 | * |
| 2730 | * The entire string is prefixed by a minus sign character '-' |
| 2731 | * (<tt>'\u002D'</tt>) if the unscaled value is less than |
| 2732 | * zero. No sign character is prefixed if the unscaled value is |
| 2733 | * zero or positive. |
| 2734 | * |
| 2735 | * Note that if the result of this method is passed to the |
| 2736 | * {@linkplain #BigDecimal(String) string constructor}, only the |
| 2737 | * numerical value of this {@code BigDecimal} will necessarily be |
| 2738 | * recovered; the representation of the new {@code BigDecimal} |
| 2739 | * may have a different scale. In particular, if this |
| 2740 | * {@code BigDecimal} has a negative scale, the string resulting |
| 2741 | * from this method will have a scale of zero when processed by |
| 2742 | * the string constructor. |
| 2743 | * |
| 2744 | * (This method behaves analogously to the {@code toString} |
| 2745 | * method in 1.4 and earlier releases.) |
| 2746 | * |
| 2747 | * @return a string representation of this {@code BigDecimal} |
| 2748 | * without an exponent field. |
| 2749 | * @since 1.5 |
| 2750 | * @see #toString() |
| 2751 | * @see #toEngineeringString() |
| 2752 | */ |
| 2753 | public String toPlainString() { |
| 2754 | BigDecimal bd = this; |
| 2755 | if (bd.scale < 0) |
| 2756 | bd = bd.setScale(0); |
| 2757 | bd.inflate(); |
| 2758 | if (bd.scale == 0) // No decimal point |
| 2759 | return bd.intVal.toString(); |
| 2760 | return bd.getValueString(bd.signum(), bd.intVal.abs().toString(), bd.scale); |
| 2761 | } |
| 2762 | |
| 2763 | /* Returns a digit.digit string */ |
| 2764 | private String getValueString(int signum, String intString, int scale) { |
| 2765 | /* Insert decimal point */ |
| 2766 | StringBuilder buf; |
| 2767 | int insertionPoint = intString.length() - scale; |
| 2768 | if (insertionPoint == 0) { /* Point goes right before intVal */ |
| 2769 | return (signum<0 ? "-0." : "0.") + intString; |
| 2770 | } else if (insertionPoint > 0) { /* Point goes inside intVal */ |
| 2771 | buf = new StringBuilder(intString); |
| 2772 | buf.insert(insertionPoint, '.'); |
| 2773 | if (signum < 0) |
| 2774 | buf.insert(0, '-'); |
| 2775 | } else { /* We must insert zeros between point and intVal */ |
| 2776 | buf = new StringBuilder(3-insertionPoint + intString.length()); |
| 2777 | buf.append(signum<0 ? "-0." : "0."); |
| 2778 | for (int i=0; i<-insertionPoint; i++) |
| 2779 | buf.append('0'); |
| 2780 | buf.append(intString); |
| 2781 | } |
| 2782 | return buf.toString(); |
| 2783 | } |
| 2784 | |
| 2785 | /** |
| 2786 | * Converts this {@code BigDecimal} to a {@code BigInteger}. |
| 2787 | * This conversion is analogous to a <a |
| 2788 | * href="http://java.sun.com/docs/books/jls/second_edition/html/conversions.doc.html#25363"><i>narrowing |
| 2789 | * primitive conversion</i></a> from {@code double} to |
| 2790 | * {@code long} as defined in the <a |
| 2791 | * href="http://java.sun.com/docs/books/jls/html/">Java Language |
| 2792 | * Specification</a>: any fractional part of this |
| 2793 | * {@code BigDecimal} will be discarded. Note that this |
| 2794 | * conversion can lose information about the precision of the |
| 2795 | * {@code BigDecimal} value. |
| 2796 | * <p> |
| 2797 | * To have an exception thrown if the conversion is inexact (in |
| 2798 | * other words if a nonzero fractional part is discarded), use the |
| 2799 | * {@link #toBigIntegerExact()} method. |
| 2800 | * |
| 2801 | * @return this {@code BigDecimal} converted to a {@code BigInteger}. |
| 2802 | */ |
| 2803 | public BigInteger toBigInteger() { |
| 2804 | // force to an integer, quietly |
| 2805 | return this.setScale(0, ROUND_DOWN).inflate().intVal; |
| 2806 | } |
| 2807 | |
| 2808 | /** |
| 2809 | * Converts this {@code BigDecimal} to a {@code BigInteger}, |
| 2810 | * checking for lost information. An exception is thrown if this |
| 2811 | * {@code BigDecimal} has a nonzero fractional part. |
| 2812 | * |
| 2813 | * @return this {@code BigDecimal} converted to a {@code BigInteger}. |
| 2814 | * @throws ArithmeticException if {@code this} has a nonzero |
| 2815 | * fractional part. |
| 2816 | * @since 1.5 |
| 2817 | */ |
| 2818 | public BigInteger toBigIntegerExact() { |
| 2819 | // round to an integer, with Exception if decimal part non-0 |
| 2820 | return this.setScale(0, ROUND_UNNECESSARY).inflate().intVal; |
| 2821 | } |
| 2822 | |
| 2823 | /** |
| 2824 | * Converts this {@code BigDecimal} to a {@code long}. This |
| 2825 | * conversion is analogous to a <a |
| 2826 | * href="http://java.sun.com/docs/books/jls/second_edition/html/conversions.doc.html#25363"><i>narrowing |
| 2827 | * primitive conversion</i></a> from {@code double} to |
| 2828 | * {@code short} as defined in the <a |
| 2829 | * href="http://java.sun.com/docs/books/jls/html/">Java Language |
| 2830 | * Specification</a>: any fractional part of this |
| 2831 | * {@code BigDecimal} will be discarded, and if the resulting |
| 2832 | * "{@code BigInteger}" is too big to fit in a |
| 2833 | * {@code long}, only the low-order 64 bits are returned. |
| 2834 | * Note that this conversion can lose information about the |
| 2835 | * overall magnitude and precision of this {@code BigDecimal} value as well |
| 2836 | * as return a result with the opposite sign. |
| 2837 | * |
| 2838 | * @return this {@code BigDecimal} converted to a {@code long}. |
| 2839 | */ |
| 2840 | public long longValue(){ |
| 2841 | return (intCompact != INFLATED && scale == 0) ? |
| 2842 | intCompact: |
| 2843 | toBigInteger().longValue(); |
| 2844 | } |
| 2845 | |
| 2846 | /** |
| 2847 | * Converts this {@code BigDecimal} to a {@code long}, checking |
| 2848 | * for lost information. If this {@code BigDecimal} has a |
| 2849 | * nonzero fractional part or is out of the possible range for a |
| 2850 | * {@code long} result then an {@code ArithmeticException} is |
| 2851 | * thrown. |
| 2852 | * |
| 2853 | * @return this {@code BigDecimal} converted to a {@code long}. |
| 2854 | * @throws ArithmeticException if {@code this} has a nonzero |
| 2855 | * fractional part, or will not fit in a {@code long}. |
| 2856 | * @since 1.5 |
| 2857 | */ |
| 2858 | public long longValueExact() { |
| 2859 | if (intCompact != INFLATED && scale == 0) |
| 2860 | return intCompact; |
| 2861 | // If more than 19 digits in integer part it cannot possibly fit |
| 2862 | if ((precision() - scale) > 19) // [OK for negative scale too] |
| 2863 | throw new java.lang.ArithmeticException("Overflow"); |
| 2864 | // Fastpath zero and < 1.0 numbers (the latter can be very slow |
| 2865 | // to round if very small) |
| 2866 | if (this.signum() == 0) |
| 2867 | return 0; |
| 2868 | if ((this.precision() - this.scale) <= 0) |
| 2869 | throw new ArithmeticException("Rounding necessary"); |
| 2870 | // round to an integer, with Exception if decimal part non-0 |
| 2871 | BigDecimal num = this.setScale(0, ROUND_UNNECESSARY).inflate(); |
| 2872 | if (num.precision() >= 19) // need to check carefully |
| 2873 | LongOverflow.check(num); |
| 2874 | return num.intVal.longValue(); |
| 2875 | } |
| 2876 | |
| 2877 | private static class LongOverflow { |
| 2878 | /** BigInteger equal to Long.MIN_VALUE. */ |
| 2879 | private static final BigInteger LONGMIN = BigInteger.valueOf(Long.MIN_VALUE); |
| 2880 | |
| 2881 | /** BigInteger equal to Long.MAX_VALUE. */ |
| 2882 | private static final BigInteger LONGMAX = BigInteger.valueOf(Long.MAX_VALUE); |
| 2883 | |
| 2884 | public static void check(BigDecimal num) { |
| 2885 | if ((num.intVal.compareTo(LONGMIN) < 0) || |
| 2886 | (num.intVal.compareTo(LONGMAX) > 0)) |
| 2887 | throw new java.lang.ArithmeticException("Overflow"); |
| 2888 | } |
| 2889 | } |
| 2890 | |
| 2891 | /** |
| 2892 | * Converts this {@code BigDecimal} to an {@code int}. This |
| 2893 | * conversion is analogous to a <a |
| 2894 | * href="http://java.sun.com/docs/books/jls/second_edition/html/conversions.doc.html#25363"><i>narrowing |
| 2895 | * primitive conversion</i></a> from {@code double} to |
| 2896 | * {@code short} as defined in the <a |
| 2897 | * href="http://java.sun.com/docs/books/jls/html/">Java Language |
| 2898 | * Specification</a>: any fractional part of this |
| 2899 | * {@code BigDecimal} will be discarded, and if the resulting |
| 2900 | * "{@code BigInteger}" is too big to fit in an |
| 2901 | * {@code int}, only the low-order 32 bits are returned. |
| 2902 | * Note that this conversion can lose information about the |
| 2903 | * overall magnitude and precision of this {@code BigDecimal} |
| 2904 | * value as well as return a result with the opposite sign. |
| 2905 | * |
| 2906 | * @return this {@code BigDecimal} converted to an {@code int}. |
| 2907 | */ |
| 2908 | public int intValue() { |
| 2909 | return (intCompact != INFLATED && scale == 0) ? |
| 2910 | (int)intCompact : |
| 2911 | toBigInteger().intValue(); |
| 2912 | } |
| 2913 | |
| 2914 | /** |
| 2915 | * Converts this {@code BigDecimal} to an {@code int}, checking |
| 2916 | * for lost information. If this {@code BigDecimal} has a |
| 2917 | * nonzero fractional part or is out of the possible range for an |
| 2918 | * {@code int} result then an {@code ArithmeticException} is |
| 2919 | * thrown. |
| 2920 | * |
| 2921 | * @return this {@code BigDecimal} converted to an {@code int}. |
| 2922 | * @throws ArithmeticException if {@code this} has a nonzero |
| 2923 | * fractional part, or will not fit in an {@code int}. |
| 2924 | * @since 1.5 |
| 2925 | */ |
| 2926 | public int intValueExact() { |
| 2927 | long num; |
| 2928 | num = this.longValueExact(); // will check decimal part |
| 2929 | if ((int)num != num) |
| 2930 | throw new java.lang.ArithmeticException("Overflow"); |
| 2931 | return (int)num; |
| 2932 | } |
| 2933 | |
| 2934 | /** |
| 2935 | * Converts this {@code BigDecimal} to a {@code short}, checking |
| 2936 | * for lost information. If this {@code BigDecimal} has a |
| 2937 | * nonzero fractional part or is out of the possible range for a |
| 2938 | * {@code short} result then an {@code ArithmeticException} is |
| 2939 | * thrown. |
| 2940 | * |
| 2941 | * @return this {@code BigDecimal} converted to a {@code short}. |
| 2942 | * @throws ArithmeticException if {@code this} has a nonzero |
| 2943 | * fractional part, or will not fit in a {@code short}. |
| 2944 | * @since 1.5 |
| 2945 | */ |
| 2946 | public short shortValueExact() { |
| 2947 | long num; |
| 2948 | num = this.longValueExact(); // will check decimal part |
| 2949 | if ((short)num != num) |
| 2950 | throw new java.lang.ArithmeticException("Overflow"); |
| 2951 | return (short)num; |
| 2952 | } |
| 2953 | |
| 2954 | /** |
| 2955 | * Converts this {@code BigDecimal} to a {@code byte}, checking |
| 2956 | * for lost information. If this {@code BigDecimal} has a |
| 2957 | * nonzero fractional part or is out of the possible range for a |
| 2958 | * {@code byte} result then an {@code ArithmeticException} is |
| 2959 | * thrown. |
| 2960 | * |
| 2961 | * @return this {@code BigDecimal} converted to a {@code byte}. |
| 2962 | * @throws ArithmeticException if {@code this} has a nonzero |
| 2963 | * fractional part, or will not fit in a {@code byte}. |
| 2964 | * @since 1.5 |
| 2965 | */ |
| 2966 | public byte byteValueExact() { |
| 2967 | long num; |
| 2968 | num = this.longValueExact(); // will check decimal part |
| 2969 | if ((byte)num != num) |
| 2970 | throw new java.lang.ArithmeticException("Overflow"); |
| 2971 | return (byte)num; |
| 2972 | } |
| 2973 | |
| 2974 | /** |
| 2975 | * Converts this {@code BigDecimal} to a {@code float}. |
| 2976 | * This conversion is similar to the <a |
| 2977 | * href="http://java.sun.com/docs/books/jls/second_edition/html/conversions.doc.html#25363"><i>narrowing |
| 2978 | * primitive conversion</i></a> from {@code double} to |
| 2979 | * {@code float} defined in the <a |
| 2980 | * href="http://java.sun.com/docs/books/jls/html/">Java Language |
| 2981 | * Specification</a>: if this {@code BigDecimal} has too great a |
| 2982 | * magnitude to represent as a {@code float}, it will be |
| 2983 | * converted to {@link Float#NEGATIVE_INFINITY} or {@link |
| 2984 | * Float#POSITIVE_INFINITY} as appropriate. Note that even when |
| 2985 | * the return value is finite, this conversion can lose |
| 2986 | * information about the precision of the {@code BigDecimal} |
| 2987 | * value. |
| 2988 | * |
| 2989 | * @return this {@code BigDecimal} converted to a {@code float}. |
| 2990 | */ |
| 2991 | public float floatValue(){ |
| 2992 | if (scale == 0 && intCompact != INFLATED) |
| 2993 | return (float)intCompact; |
| 2994 | // Somewhat inefficient, but guaranteed to work. |
| 2995 | return Float.parseFloat(this.toString()); |
| 2996 | } |
| 2997 | |
| 2998 | /** |
| 2999 | * Converts this {@code BigDecimal} to a {@code double}. |
| 3000 | * This conversion is similar to the <a |
| 3001 | * href="http://java.sun.com/docs/books/jls/second_edition/html/conversions.doc.html#25363"><i>narrowing |
| 3002 | * primitive conversion</i></a> from {@code double} to |
| 3003 | * {@code float} as defined in the <a |
| 3004 | * href="http://java.sun.com/docs/books/jls/html/">Java Language |
| 3005 | * Specification</a>: if this {@code BigDecimal} has too great a |
| 3006 | * magnitude represent as a {@code double}, it will be |
| 3007 | * converted to {@link Double#NEGATIVE_INFINITY} or {@link |
| 3008 | * Double#POSITIVE_INFINITY} as appropriate. Note that even when |
| 3009 | * the return value is finite, this conversion can lose |
| 3010 | * information about the precision of the {@code BigDecimal} |
| 3011 | * value. |
| 3012 | * |
| 3013 | * @return this {@code BigDecimal} converted to a {@code double}. |
| 3014 | */ |
| 3015 | public double doubleValue(){ |
| 3016 | if (scale == 0 && intCompact != INFLATED) |
| 3017 | return (double)intCompact; |
| 3018 | // Somewhat inefficient, but guaranteed to work. |
| 3019 | return Double.parseDouble(this.toString()); |
| 3020 | } |
| 3021 | |
| 3022 | /** |
| 3023 | * Returns the size of an ulp, a unit in the last place, of this |
| 3024 | * {@code BigDecimal}. An ulp of a nonzero {@code BigDecimal} |
| 3025 | * value is the positive distance between this value and the |
| 3026 | * {@code BigDecimal} value next larger in magnitude with the |
| 3027 | * same number of digits. An ulp of a zero value is numerically |
| 3028 | * equal to 1 with the scale of {@code this}. The result is |
| 3029 | * stored with the same scale as {@code this} so the result |
| 3030 | * for zero and nonzero values is equal to {@code [1, |
| 3031 | * this.scale()]}. |
| 3032 | * |
| 3033 | * @return the size of an ulp of {@code this} |
| 3034 | * @since 1.5 |
| 3035 | */ |
| 3036 | public BigDecimal ulp() { |
| 3037 | return BigDecimal.valueOf(1, this.scale()); |
| 3038 | } |
| 3039 | |
| 3040 | // Private "Helper" Methods |
| 3041 | |
| 3042 | /** |
| 3043 | * Lay out this {@code BigDecimal} into a {@code char[]} array. |
| 3044 | * The Java 1.2 equivalent to this was called {@code getValueString}. |
| 3045 | * |
| 3046 | * @param sci {@code true} for Scientific exponential notation; |
| 3047 | * {@code false} for Engineering |
| 3048 | * @return string with canonical string representation of this |
| 3049 | * {@code BigDecimal} |
| 3050 | */ |
| 3051 | private String layoutChars(boolean sci) { |
| 3052 | if (scale == 0) // zero scale is trivial |
| 3053 | return (intCompact != INFLATED) ? |
| 3054 | Long.toString(intCompact): |
| 3055 | intVal.toString(); |
| 3056 | |
| 3057 | // Get the significand as an absolute value |
| 3058 | char coeff[]; |
| 3059 | if (intCompact != INFLATED) |
| 3060 | coeff = Long.toString(Math.abs(intCompact)).toCharArray(); |
| 3061 | else |
| 3062 | coeff = intVal.abs().toString().toCharArray(); |
| 3063 | |
| 3064 | // Construct a buffer, with sufficient capacity for all cases. |
| 3065 | // If E-notation is needed, length will be: +1 if negative, +1 |
| 3066 | // if '.' needed, +2 for "E+", + up to 10 for adjusted exponent. |
| 3067 | // Otherwise it could have +1 if negative, plus leading "0.00000" |
| 3068 | StringBuilder buf=new StringBuilder(coeff.length+14); |
| 3069 | if (signum() < 0) // prefix '-' if negative |
| 3070 | buf.append('-'); |
| 3071 | long adjusted = -(long)scale + (coeff.length-1); |
| 3072 | if ((scale >= 0) && (adjusted >= -6)) { // plain number |
| 3073 | int pad = scale - coeff.length; // count of padding zeros |
| 3074 | if (pad >= 0) { // 0.xxx form |
| 3075 | buf.append('0'); |
| 3076 | buf.append('.'); |
| 3077 | for (; pad>0; pad--) { |
| 3078 | buf.append('0'); |
| 3079 | } |
| 3080 | buf.append(coeff); |
| 3081 | } else { // xx.xx form |
| 3082 | buf.append(coeff, 0, -pad); |
| 3083 | buf.append('.'); |
| 3084 | buf.append(coeff, -pad, scale); |
| 3085 | } |
| 3086 | } else { // E-notation is needed |
| 3087 | if (sci) { // Scientific notation |
| 3088 | buf.append(coeff[0]); // first character |
| 3089 | if (coeff.length > 1) { // more to come |
| 3090 | buf.append('.'); |
| 3091 | buf.append(coeff, 1, coeff.length-1); |
| 3092 | } |
| 3093 | } else { // Engineering notation |
| 3094 | int sig = (int)(adjusted % 3); |
| 3095 | if (sig < 0) |
| 3096 | sig += 3; // [adjusted was negative] |
| 3097 | adjusted -= sig; // now a multiple of 3 |
| 3098 | sig++; |
| 3099 | if (signum() == 0) { |
| 3100 | switch (sig) { |
| 3101 | case 1: |
| 3102 | buf.append('0'); // exponent is a multiple of three |
| 3103 | break; |
| 3104 | case 2: |
| 3105 | buf.append("0.00"); |
| 3106 | adjusted += 3; |
| 3107 | break; |
| 3108 | case 3: |
| 3109 | buf.append("0.0"); |
| 3110 | adjusted += 3; |
| 3111 | break; |
| 3112 | default: |
| 3113 | throw new AssertionError("Unexpected sig value " + sig); |
| 3114 | } |
| 3115 | } else if (sig >= coeff.length) { // significand all in integer |
| 3116 | buf.append(coeff, 0, coeff.length); |
| 3117 | // may need some zeros, too |
| 3118 | for (int i = sig - coeff.length; i > 0; i--) |
| 3119 | buf.append('0'); |
| 3120 | } else { // xx.xxE form |
| 3121 | buf.append(coeff, 0, sig); |
| 3122 | buf.append('.'); |
| 3123 | buf.append(coeff, sig, coeff.length-sig); |
| 3124 | } |
| 3125 | } |
| 3126 | if (adjusted != 0) { // [!sci could have made 0] |
| 3127 | buf.append('E'); |
| 3128 | if (adjusted > 0) // force sign for positive |
| 3129 | buf.append('+'); |
| 3130 | buf.append(adjusted); |
| 3131 | } |
| 3132 | } |
| 3133 | return buf.toString(); |
| 3134 | } |
| 3135 | |
| 3136 | /** |
| 3137 | * Return 10 to the power n, as a {@code BigInteger}. |
| 3138 | * |
| 3139 | * @param n the power of ten to be returned (>=0) |
| 3140 | * @return a {@code BigInteger} with the value (10<sup>n</sup>) |
| 3141 | */ |
| 3142 | private static BigInteger tenToThe(int n) { |
| 3143 | if (n < TENPOWERS.length) // use value from constant array |
| 3144 | return TENPOWERS[n]; |
| 3145 | // BigInteger.pow is slow, so make 10**n by constructing a |
| 3146 | // BigInteger from a character string (still not very fast) |
| 3147 | char tenpow[] = new char[n + 1]; |
| 3148 | tenpow[0] = '1'; |
| 3149 | for (int i = 1; i <= n; i++) |
| 3150 | tenpow[i] = '0'; |
| 3151 | return new BigInteger(tenpow); |
| 3152 | } |
| 3153 | private static BigInteger TENPOWERS[] = {BigInteger.ONE, |
| 3154 | BigInteger.valueOf(10), BigInteger.valueOf(100), |
| 3155 | BigInteger.valueOf(1000), BigInteger.valueOf(10000), |
| 3156 | BigInteger.valueOf(100000), BigInteger.valueOf(1000000), |
| 3157 | BigInteger.valueOf(10000000), BigInteger.valueOf(100000000), |
| 3158 | BigInteger.valueOf(1000000000)}; |
| 3159 | |
| 3160 | /** |
| 3161 | * Compute val * 10 ^ n; return this product if it is |
| 3162 | * representable as a long, INFLATED otherwise. |
| 3163 | */ |
| 3164 | private static long longTenToThe(long val, int n) { |
| 3165 | // System.err.print("\tval " + val + "\t power " + n + "\tresult "); |
| 3166 | if (n >= 0 && n < thresholds.length) { |
| 3167 | if (Math.abs(val) <= thresholds[n][0] ) { |
| 3168 | // System.err.println(val * thresholds[n][1]); |
| 3169 | return val * thresholds[n][1]; |
| 3170 | } |
| 3171 | } |
| 3172 | // System.err.println(INFLATED); |
| 3173 | return INFLATED; |
| 3174 | } |
| 3175 | |
| 3176 | private static long thresholds[][] = { |
| 3177 | {Long.MAX_VALUE, 1L}, // 0 |
| 3178 | {Long.MAX_VALUE/10L, 10L}, // 1 |
| 3179 | {Long.MAX_VALUE/100L, 100L}, // 2 |
| 3180 | {Long.MAX_VALUE/1000L, 1000L}, // 3 |
| 3181 | {Long.MAX_VALUE/10000L, 10000L}, // 4 |
| 3182 | {Long.MAX_VALUE/100000L, 100000L}, // 5 |
| 3183 | {Long.MAX_VALUE/1000000L, 1000000L}, // 6 |
| 3184 | {Long.MAX_VALUE/10000000L, 10000000L}, // 7 |
| 3185 | {Long.MAX_VALUE/100000000L, 100000000L}, // 8 |
| 3186 | {Long.MAX_VALUE/1000000000L, 1000000000L}, // 9 |
| 3187 | {Long.MAX_VALUE/10000000000L, 10000000000L}, // 10 |
| 3188 | {Long.MAX_VALUE/100000000000L, 100000000000L}, // 11 |
| 3189 | {Long.MAX_VALUE/1000000000000L, 1000000000000L},// 12 |
| 3190 | {Long.MAX_VALUE/100000000000000L, 10000000000000L},// 13 |
| 3191 | }; |
| 3192 | |
| 3193 | private static boolean compactLong(long val) { |
| 3194 | return (val != Long.MIN_VALUE); |
| 3195 | } |
| 3196 | |
| 3197 | /** |
| 3198 | * Assign appropriate BigInteger to intVal field if intVal is |
| 3199 | * null, i.e. the compact representation is in use. |
| 3200 | */ |
| 3201 | private BigDecimal inflate() { |
| 3202 | if (intVal == null) |
| 3203 | intVal = BigInteger.valueOf(intCompact); |
| 3204 | return this; |
| 3205 | } |
| 3206 | |
| 3207 | /** |
| 3208 | * Match the scales of two {@code BigDecimal}s to align their |
| 3209 | * least significant digits. |
| 3210 | * |
| 3211 | * <p>If the scales of val[0] and val[1] differ, rescale |
| 3212 | * (non-destructively) the lower-scaled {@code BigDecimal} so |
| 3213 | * they match. That is, the lower-scaled reference will be |
| 3214 | * replaced by a reference to a new object with the same scale as |
| 3215 | * the other {@code BigDecimal}. |
| 3216 | * |
| 3217 | * @param val array of two elements referring to the two |
| 3218 | * {@code BigDecimal}s to be aligned. |
| 3219 | */ |
| 3220 | private static void matchScale(BigDecimal[] val) { |
| 3221 | if (val[0].scale < val[1].scale) |
| 3222 | val[0] = val[0].setScale(val[1].scale); |
| 3223 | else if (val[1].scale < val[0].scale) |
| 3224 | val[1] = val[1].setScale(val[0].scale); |
| 3225 | } |
| 3226 | |
| 3227 | /** |
| 3228 | * Reconstitute the {@code BigDecimal} instance from a stream (that is, |
| 3229 | * deserialize it). |
| 3230 | * |
| 3231 | * @param s the stream being read. |
| 3232 | */ |
| 3233 | private void readObject(java.io.ObjectInputStream s) |
| 3234 | throws java.io.IOException, ClassNotFoundException { |
| 3235 | // Read in all fields |
| 3236 | s.defaultReadObject(); |
| 3237 | // validate possibly bad fields |
| 3238 | if (intVal == null) { |
| 3239 | String message = "BigDecimal: null intVal in stream"; |
| 3240 | throw new java.io.StreamCorruptedException(message); |
| 3241 | // [all values of scale are now allowed] |
| 3242 | } |
| 3243 | // Set intCompact to uninitialized value; could also see if the |
| 3244 | // intVal was small enough to fit as a compact value. |
| 3245 | intCompact = INFLATED; |
| 3246 | } |
| 3247 | |
| 3248 | /** |
| 3249 | * Serialize this {@code BigDecimal} to the stream in question |
| 3250 | * |
| 3251 | * @param s the stream to serialize to. |
| 3252 | */ |
| 3253 | private void writeObject(java.io.ObjectOutputStream s) |
| 3254 | throws java.io.IOException { |
| 3255 | // Must inflate to maintain compatible serial form. |
| 3256 | this.inflate(); |
| 3257 | |
| 3258 | // Write proper fields |
| 3259 | s.defaultWriteObject(); |
| 3260 | } |
| 3261 | |
| 3262 | /** |
| 3263 | * Returns the length of this {@code BigDecimal}, in decimal digits. |
| 3264 | * |
| 3265 | * Notes: |
| 3266 | *<ul> |
| 3267 | * <li> This is performance-critical; most operations where a |
| 3268 | * context is supplied will need at least one call to this |
| 3269 | * method. |
| 3270 | * |
| 3271 | * <li> This should be a method on BigInteger; the call to this |
| 3272 | * method in precision() can then be replaced with the |
| 3273 | * term: intVal.digitLength(). It could also be called |
| 3274 | * precision() in BigInteger. |
| 3275 | * |
| 3276 | * Better still -- the precision lookaside could be moved to |
| 3277 | * BigInteger, too. |
| 3278 | * |
| 3279 | * <li> This could/should use MutableBigIntegers directly for the |
| 3280 | * reduction loop. |
| 3281 | *<ul> |
| 3282 | * @return the length of the unscaled value, in decimal digits |
| 3283 | */ |
| 3284 | private int digitLength() { |
| 3285 | if (intCompact != INFLATED && Math.abs(intCompact) <= Integer.MAX_VALUE) |
| 3286 | return intLength(Math.abs((int)intCompact)); |
| 3287 | if (signum() == 0) // 0 is one decimal digit |
| 3288 | return 1; |
| 3289 | this.inflate(); |
| 3290 | // we have a nonzero magnitude |
| 3291 | BigInteger work = intVal; |
| 3292 | int digits = 0; // counter |
| 3293 | for (;work.mag.length>1;) { |
| 3294 | // here when more than one integer in the magnitude; divide |
| 3295 | // by a billion (reduce by 9 digits) and try again |
| 3296 | work = work.divide(TENPOWERS[9]); |
| 3297 | digits += 9; |
| 3298 | if (work.signum() == 0) // the division was exact |
| 3299 | return digits; // (a power of a billion) |
| 3300 | } |
| 3301 | // down to a simple nonzero integer |
| 3302 | digits += intLength(work.mag[0]); |
| 3303 | // System.out.println("digitLength... "+this+" -> "+digits); |
| 3304 | return digits; |
| 3305 | } |
| 3306 | |
| 3307 | private static int[] ilogTable = { |
| 3308 | 0, |
| 3309 | 9, |
| 3310 | 99, |
| 3311 | 999, |
| 3312 | 9999, |
| 3313 | 99999, |
| 3314 | 999999, |
| 3315 | 9999999, |
| 3316 | 99999999, |
| 3317 | 999999999, |
| 3318 | Integer.MAX_VALUE}; |
| 3319 | |
| 3320 | /** |
| 3321 | * Returns the length of an unsigned {@code int}, in decimal digits. |
| 3322 | * @param i the {@code int} (treated as unsigned) |
| 3323 | * @return the length of the unscaled value, in decimal digits |
| 3324 | */ |
| 3325 | private int intLength(int x) { |
| 3326 | int digits; |
| 3327 | if (x < 0) { // 'negative' is 10 digits unsigned |
| 3328 | return 10; |
| 3329 | } else { // positive integer |
| 3330 | if (x <= 9) |
| 3331 | return 1; |
| 3332 | // "Hacker's Delight" section 11-4 |
| 3333 | for(int i = -1; ; i++) { |
| 3334 | if (x <= ilogTable[i+1]) |
| 3335 | return i +1; |
| 3336 | } |
| 3337 | } |
| 3338 | } |
| 3339 | |
| 3340 | /** |
| 3341 | * Remove insignificant trailing zeros from this |
| 3342 | * {@code BigDecimal} until the preferred scale is reached or no |
| 3343 | * more zeros can be removed. If the preferred scale is less than |
| 3344 | * Integer.MIN_VALUE, all the trailing zeros will be removed. |
| 3345 | * |
| 3346 | * {@code BigInteger} assistance could help, here? |
| 3347 | * |
| 3348 | * <p>WARNING: This method should only be called on new objects as |
| 3349 | * it mutates the value fields. |
| 3350 | * |
| 3351 | * @return this {@code BigDecimal} with a scale possibly reduced |
| 3352 | * to be closed to the preferred scale. |
| 3353 | */ |
| 3354 | private BigDecimal stripZerosToMatchScale(long preferredScale) { |
| 3355 | boolean compact = (intCompact != INFLATED); |
| 3356 | this.inflate(); |
| 3357 | BigInteger qr[]; // quotient-remainder pair |
| 3358 | while ( intVal.abs().compareTo(BigInteger.TEN) >= 0 && |
| 3359 | scale > preferredScale) { |
| 3360 | if (intVal.testBit(0)) |
| 3361 | break; // odd number cannot end in 0 |
| 3362 | qr = intVal.divideAndRemainder(BigInteger.TEN); |
| 3363 | if (qr[1].signum() != 0) |
| 3364 | break; // non-0 remainder |
| 3365 | intVal=qr[0]; |
| 3366 | scale = checkScale((long)scale-1); // could Overflow |
| 3367 | if (precision > 0) // adjust precision if known |
| 3368 | precision--; |
| 3369 | } |
| 3370 | if (compact) |
| 3371 | intCompact = intVal.longValue(); |
| 3372 | return this; |
| 3373 | } |
| 3374 | |
| 3375 | /** |
| 3376 | * Check a scale for Underflow or Overflow. If this BigDecimal is |
| 3377 | * uninitialized or initialized and nonzero, throw an exception if |
| 3378 | * the scale is out of range. If this is zero, saturate the scale |
| 3379 | * to the extreme value of the right sign if the scale is out of |
| 3380 | * range. |
| 3381 | * |
| 3382 | * @param val The new scale. |
| 3383 | * @throws ArithmeticException (overflow or underflow) if the new |
| 3384 | * scale is out of range. |
| 3385 | * @return validated scale as an int. |
| 3386 | */ |
| 3387 | private int checkScale(long val) { |
| 3388 | if ((int)val != val) { |
| 3389 | if ((this.intCompact != INFLATED && this.intCompact != 0) || |
| 3390 | (this.intVal != null && this.signum() != 0) || |
| 3391 | (this.intVal == null && this.intCompact == INFLATED) ) { |
| 3392 | if (val > Integer.MAX_VALUE) |
| 3393 | throw new ArithmeticException("Underflow"); |
| 3394 | if (val < Integer.MIN_VALUE) |
| 3395 | throw new ArithmeticException("Overflow"); |
| 3396 | } else { |
| 3397 | return (val > Integer.MAX_VALUE)?Integer.MAX_VALUE:Integer.MIN_VALUE; |
| 3398 | } |
| 3399 | } |
| 3400 | return (int)val; |
| 3401 | } |
| 3402 | |
| 3403 | /** |
| 3404 | * Round an operand; used only if digits > 0. Does not change |
| 3405 | * {@code this}; if rounding is needed a new {@code BigDecimal} |
| 3406 | * is created and returned. |
| 3407 | * |
| 3408 | * @param mc the context to use. |
| 3409 | * @throws ArithmeticException if the result is inexact but the |
| 3410 | * rounding mode is {@code UNNECESSARY}. |
| 3411 | */ |
| 3412 | private BigDecimal roundOp(MathContext mc) { |
| 3413 | BigDecimal rounded = doRound(mc); |
| 3414 | return rounded; |
| 3415 | } |
| 3416 | |
| 3417 | /** Round this BigDecimal according to the MathContext settings; |
| 3418 | * used only if precision {@literal >} 0. |
| 3419 | * |
| 3420 | * <p>WARNING: This method should only be called on new objects as |
| 3421 | * it mutates the value fields. |
| 3422 | * |
| 3423 | * @param mc the context to use. |
| 3424 | * @throws ArithmeticException if the rounding mode is |
| 3425 | * {@code RoundingMode.UNNECESSARY} and the |
| 3426 | * {@code BigDecimal} operation would require rounding. |
| 3427 | */ |
| 3428 | private void roundThis(MathContext mc) { |
| 3429 | BigDecimal rounded = doRound(mc); |
| 3430 | if (rounded == this) // wasn't rounded |
| 3431 | return; |
| 3432 | this.intVal = rounded.intVal; |
| 3433 | this.intCompact = rounded.intCompact; |
| 3434 | this.scale = rounded.scale; |
| 3435 | this.precision = rounded.precision; |
| 3436 | } |
| 3437 | |
| 3438 | /** |
| 3439 | * Returns a {@code BigDecimal} rounded according to the |
| 3440 | * MathContext settings; used only if {@code mc.precision > 0}. |
| 3441 | * Does not change {@code this}; if rounding is needed a new |
| 3442 | * {@code BigDecimal} is created and returned. |
| 3443 | * |
| 3444 | * @param mc the context to use. |
| 3445 | * @return a {@code BigDecimal} rounded according to the MathContext |
| 3446 | * settings. May return this, if no rounding needed. |
| 3447 | * @throws ArithmeticException if the rounding mode is |
| 3448 | * {@code RoundingMode.UNNECESSARY} and the |
| 3449 | * result is inexact. |
| 3450 | */ |
| 3451 | private BigDecimal doRound(MathContext mc) { |
| 3452 | this.inflate(); |
| 3453 | if (precision == 0) { |
| 3454 | if (mc.roundingMax != null |
| 3455 | && intVal.compareTo(mc.roundingMax) < 0 |
| 3456 | && intVal.compareTo(mc.roundingMin) > 0) |
| 3457 | return this; // no rounding needed |
| 3458 | precision(); // find it |
| 3459 | } |
| 3460 | int drop = precision - mc.precision; // digits to discard |
| 3461 | if (drop <= 0) // we fit |
| 3462 | return this; |
| 3463 | BigDecimal rounded = dropDigits(mc, drop); |
| 3464 | // we need to double-check, in case of the 999=>1000 case |
| 3465 | return rounded.doRound(mc); |
| 3466 | } |
| 3467 | |
| 3468 | /** |
| 3469 | * Removes digits from the significand of a {@code BigDecimal}, |
| 3470 | * rounding according to the MathContext settings. Does not |
| 3471 | * change {@code this}; a new {@code BigDecimal} is always |
| 3472 | * created and returned. |
| 3473 | * |
| 3474 | * <p>Actual rounding is carried out, as before, by the divide |
| 3475 | * method, as this minimized code changes. It might be more |
| 3476 | * efficient in most cases to move rounding to here, so we can do |
| 3477 | * a round-to-length rather than round-to-scale. |
| 3478 | * |
| 3479 | * @param mc the context to use. |
| 3480 | * @param drop the number of digits to drop, must be {@literal >} 0 |
| 3481 | * @return a {@code BigDecimal} rounded according to the MathContext |
| 3482 | * settings. May return {@code this}, if no rounding needed. |
| 3483 | * @throws ArithmeticException if the rounding mode is |
| 3484 | * {@code RoundingMode.UNNECESSARY} and the |
| 3485 | * result is inexact. |
| 3486 | */ |
| 3487 | private BigDecimal dropDigits(MathContext mc, int drop) { |
| 3488 | // here if we need to round; make the divisor = 10**drop) |
| 3489 | // [calculating the BigInteger here saves setScale later] |
| 3490 | BigDecimal divisor = new BigDecimal(tenToThe(drop), 0); |
| 3491 | |
| 3492 | // divide to same scale to force round to length |
| 3493 | BigDecimal rounded = this.divide(divisor, scale, |
| 3494 | mc.roundingMode.oldMode); |
| 3495 | rounded.scale = checkScale((long)rounded.scale - drop ); // adjust the scale |
| 3496 | return rounded; |
| 3497 | } |
| 3498 | |
| 3499 | private static int longCompareTo(long x, long y) { |
| 3500 | return (x < y) ? -1 : (x == y) ? 0 : 1; |
| 3501 | } |
| 3502 | |
| 3503 | /* |
| 3504 | * Internal printing routine |
| 3505 | */ |
| 3506 | private static void print(String name, BigDecimal bd) { |
| 3507 | System.err.format("%s:\tintCompact %d\tintVal %d\tscale %d\tprecision %d%n", |
| 3508 | name, |
| 3509 | bd.intCompact, |
| 3510 | bd.intVal, |
| 3511 | bd.scale, |
| 3512 | bd.precision); |
| 3513 | } |
| 3514 | |
| 3515 | /** |
| 3516 | * Check internal invariants of this BigDecimal. These invariants |
| 3517 | * include: |
| 3518 | * |
| 3519 | * <ul> |
| 3520 | * |
| 3521 | * <li>The object must be initialized; either intCompact must not be |
| 3522 | * INFLATED or intVal is non-null. Both of these conditions may |
| 3523 | * be true. |
| 3524 | * |
| 3525 | * <li>If both intCompact and intVal and set, their values must be |
| 3526 | * consistent. |
| 3527 | * |
| 3528 | * <li>If precision is nonzero, it must have the right value. |
| 3529 | * </ul> |
| 3530 | */ |
| 3531 | private BigDecimal audit() { |
| 3532 | // Check precision |
| 3533 | if (precision > 0) { |
| 3534 | if (precision != digitLength()) { |
| 3535 | print("audit", this); |
| 3536 | throw new AssertionError("precision mismatch"); |
| 3537 | } |
| 3538 | } |
| 3539 | |
| 3540 | if (intCompact == INFLATED) { |
| 3541 | if (intVal == null) { |
| 3542 | print("audit", this); |
| 3543 | throw new AssertionError("null intVal"); |
| 3544 | } |
| 3545 | } else { |
| 3546 | if (intVal != null) { |
| 3547 | long val = intVal.longValue(); |
| 3548 | if (val != intCompact) { |
| 3549 | print("audit", this); |
| 3550 | throw new AssertionError("Inconsistent state, intCompact=" + |
| 3551 | intCompact + "\t intVal=" + val); |
| 3552 | } |
| 3553 | } |
| 3554 | } |
| 3555 | return this; |
| 3556 | } |
| 3557 | } |