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1 /* |
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2 * Copyright (c) 2003, 2014, Oracle and/or its affiliates. All rights reserved. |
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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4 * |
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5 * This code is free software; you can redistribute it and/or modify it |
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6 * under the terms of the GNU General Public License version 2 only, as |
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7 * published by the Free Software Foundation. Oracle designates this |
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8 * particular file as subject to the "Classpath" exception as provided |
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9 * by Oracle in the LICENSE file that accompanied this code. |
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10 * |
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11 * This code is distributed in the hope that it will be useful, but WITHOUT |
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12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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14 * version 2 for more details (a copy is included in the LICENSE file that |
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15 * accompanied this code). |
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16 * |
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17 * You should have received a copy of the GNU General Public License version |
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18 * 2 along with this work; if not, write to the Free Software Foundation, |
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19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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20 * |
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21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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22 * or visit www.oracle.com if you need additional information or have any |
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23 * questions. |
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24 */ |
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25 |
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26 package sun.misc; |
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27 |
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28 /** |
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29 * This class contains additional constants documenting limits of the |
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30 * <code>double</code> type. |
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31 * |
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32 * @author Joseph D. Darcy |
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33 */ |
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34 |
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35 public class DoubleConsts { |
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36 /** |
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37 * Don't let anyone instantiate this class. |
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38 */ |
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39 private DoubleConsts() {} |
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40 |
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41 public static final double POSITIVE_INFINITY = java.lang.Double.POSITIVE_INFINITY; |
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42 public static final double NEGATIVE_INFINITY = java.lang.Double.NEGATIVE_INFINITY; |
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43 public static final double NaN = java.lang.Double.NaN; |
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44 public static final double MAX_VALUE = java.lang.Double.MAX_VALUE; |
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45 public static final double MIN_VALUE = java.lang.Double.MIN_VALUE; |
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46 |
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47 /** |
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48 * A constant holding the smallest positive normal value of type |
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49 * <code>double</code>, 2<sup>-1022</sup>. It is equal to the |
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50 * value returned by |
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51 * <code>Double.longBitsToDouble(0x0010000000000000L)</code>. |
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52 * |
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53 * @since 1.5 |
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54 */ |
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55 public static final double MIN_NORMAL = 2.2250738585072014E-308; |
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56 |
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57 |
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58 /** |
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59 * The number of logical bits in the significand of a |
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60 * <code>double</code> number, including the implicit bit. |
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61 */ |
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62 public static final int SIGNIFICAND_WIDTH = 53; |
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63 |
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64 /** |
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65 * Maximum exponent a finite <code>double</code> number may have. |
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66 * It is equal to the value returned by |
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67 * <code>Math.ilogb(Double.MAX_VALUE)</code>. |
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68 */ |
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69 public static final int MAX_EXPONENT = 1023; |
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70 |
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71 /** |
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72 * Minimum exponent a normalized <code>double</code> number may |
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73 * have. It is equal to the value returned by |
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74 * <code>Math.ilogb(Double.MIN_NORMAL)</code>. |
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75 */ |
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76 public static final int MIN_EXPONENT = -1022; |
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77 |
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78 /** |
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79 * The exponent the smallest positive <code>double</code> |
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80 * subnormal value would have if it could be normalized.. |
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81 */ |
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82 public static final int MIN_SUB_EXPONENT = MIN_EXPONENT - |
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83 (SIGNIFICAND_WIDTH - 1); |
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84 |
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85 /** |
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86 * Bias used in representing a <code>double</code> exponent. |
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87 */ |
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88 public static final int EXP_BIAS = 1023; |
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89 |
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90 /** |
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91 * Bit mask to isolate the sign bit of a <code>double</code>. |
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92 */ |
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93 public static final long SIGN_BIT_MASK = 0x8000000000000000L; |
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94 |
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95 /** |
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96 * Bit mask to isolate the exponent field of a |
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97 * <code>double</code>. |
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98 */ |
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99 public static final long EXP_BIT_MASK = 0x7FF0000000000000L; |
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100 |
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101 /** |
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102 * Bit mask to isolate the significand field of a |
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103 * <code>double</code>. |
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104 */ |
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105 public static final long SIGNIF_BIT_MASK = 0x000FFFFFFFFFFFFFL; |
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106 |
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107 static { |
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108 // verify bit masks cover all bit positions and that the bit |
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109 // masks are non-overlapping |
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110 assert(((SIGN_BIT_MASK | EXP_BIT_MASK | SIGNIF_BIT_MASK) == ~0L) && |
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111 (((SIGN_BIT_MASK & EXP_BIT_MASK) == 0L) && |
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112 ((SIGN_BIT_MASK & SIGNIF_BIT_MASK) == 0L) && |
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113 ((EXP_BIT_MASK & SIGNIF_BIT_MASK) == 0L))); |
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114 } |
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115 } |