jdk/src/share/classes/sun/misc/FloatConsts.java
author chegar
Mon, 08 Apr 2013 06:15:18 +0100
changeset 18223 35a5c2462991
parent 5506 202f599c92aa
child 22634 9c18aebe9229
permissions -rw-r--r--
8008593: Better URLClassLoader resource management Reviewed-by: alanb, sherman, hawtin
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/*
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 * Copyright (c) 2003, Oracle and/or its affiliates. All rights reserved.
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 *
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 * This code is free software; you can redistribute it and/or modify it
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 * under the terms of the GNU General Public License version 2 only, as
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 * published by the Free Software Foundation.  Oracle designates this
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 * particular file as subject to the "Classpath" exception as provided
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 * by Oracle in the LICENSE file that accompanied this code.
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 *
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 * This code is distributed in the hope that it will be useful, but WITHOUT
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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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 * version 2 for more details (a copy is included in the LICENSE file that
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 * accompanied this code).
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 *
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 * You should have received a copy of the GNU General Public License version
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 * 2 along with this work; if not, write to the Free Software Foundation,
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 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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 *
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 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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 * or visit www.oracle.com if you need additional information or have any
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 * questions.
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 */
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package sun.misc;
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/**
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 * This class contains additional constants documenting limits of the
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 * <code>float</code> type.
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 *
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 * @author Joseph D. Darcy
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 */
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public class FloatConsts {
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    /**
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     * Don't let anyone instantiate this class.
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     */
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    private FloatConsts() {}
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    public static final float POSITIVE_INFINITY = java.lang.Float.POSITIVE_INFINITY;
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    public static final float NEGATIVE_INFINITY = java.lang.Float.NEGATIVE_INFINITY;
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    public static final float NaN = java.lang.Float.NaN;
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    public static final float MAX_VALUE = java.lang.Float.MAX_VALUE;
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    public static final float MIN_VALUE = java.lang.Float.MIN_VALUE;
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    /**
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     * A constant holding the smallest positive normal value of type
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     * <code>float</code>, 2<sup>-126</sup>.  It is equal to the value
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     * returned by <code>Float.intBitsToFloat(0x00800000)</code>.
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     */
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    public static final float   MIN_NORMAL      = 1.17549435E-38f;
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    /**
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     * The number of logical bits in the significand of a
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     * <code>float</code> number, including the implicit bit.
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     */
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    public static final int SIGNIFICAND_WIDTH   = 24;
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    /**
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     * Maximum exponent a finite <code>float</code> number may have.
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     * It is equal to the value returned by
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     * <code>Math.ilogb(Float.MAX_VALUE)</code>.
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     */
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    public static final int     MAX_EXPONENT    = 127;
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    /**
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     * Minimum exponent a normalized <code>float</code> number may
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     * have.  It is equal to the value returned by
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     * <code>Math.ilogb(Float.MIN_NORMAL)</code>.
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     */
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    public static final int     MIN_EXPONENT    = -126;
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    /**
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     * The exponent the smallest positive <code>float</code> subnormal
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     * value would have if it could be normalized.  It is equal to the
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     * value returned by <code>FpUtils.ilogb(Float.MIN_VALUE)</code>.
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     */
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    public static final int     MIN_SUB_EXPONENT = MIN_EXPONENT -
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                                                   (SIGNIFICAND_WIDTH - 1);
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    /**
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     * Bias used in representing a <code>float</code> exponent.
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     */
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    public static final int     EXP_BIAS        = 127;
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    /**
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     * Bit mask to isolate the sign bit of a <code>float</code>.
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     */
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    public static final int     SIGN_BIT_MASK   = 0x80000000;
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    /**
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     * Bit mask to isolate the exponent field of a
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     * <code>float</code>.
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     */
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    public static final int     EXP_BIT_MASK    = 0x7F800000;
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    /**
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     * Bit mask to isolate the significand field of a
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     * <code>float</code>.
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     */
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    public static final int     SIGNIF_BIT_MASK = 0x007FFFFF;
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    static {
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        // verify bit masks cover all bit positions and that the bit
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        // masks are non-overlapping
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        assert(((SIGN_BIT_MASK | EXP_BIT_MASK | SIGNIF_BIT_MASK) == ~0) &&
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               (((SIGN_BIT_MASK & EXP_BIT_MASK) == 0) &&
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                ((SIGN_BIT_MASK & SIGNIF_BIT_MASK) == 0) &&
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                ((EXP_BIT_MASK & SIGNIF_BIT_MASK) == 0)));
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    }
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}