DoubleConsts.java

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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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 *
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package sun.misc;

/**
 * This class contains additional constants documenting limits of the
 * <code>double</code> type.
 *
 * @author Joseph D. Darcy
 */

public class DoubleConsts {
    /**
     * Don't let anyone instantiate this class.
     */
    private DoubleConsts() {}

    public static final double POSITIVE_INFINITY = java.lang.Double.POSITIVE_INFINITY;
    public static final double NEGATIVE_INFINITY = java.lang.Double.NEGATIVE_INFINITY;
    public static final double NaN = java.lang.Double.NaN;
    public static final double MAX_VALUE = java.lang.Double.MAX_VALUE;
    public static final double MIN_VALUE = java.lang.Double.MIN_VALUE;

    /**
     * A constant holding the smallest positive normal value of type
     * <code>double</code>, 2<sup>-1022</sup>.  It is equal to the
     * value returned by
     * <code>Double.longBitsToDouble(0x0010000000000000L)</code>.
     *
     * @since 1.5
     */
    public static final double  MIN_NORMAL      = 2.2250738585072014E-308;


    /**
     * The number of logical bits in the significand of a
     * <code>double</code> number, including the implicit bit.
     */
    public static final int SIGNIFICAND_WIDTH   = 53;

    /**
     * Maximum exponent a finite <code>double</code> number may have.
     * It is equal to the value returned by
     * <code>Math.ilogb(Double.MAX_VALUE)</code>.
     */
    public static final int     MAX_EXPONENT    = 1023;

    /**
     * Minimum exponent a normalized <code>double</code> number may
     * have.  It is equal to the value returned by
     * <code>Math.ilogb(Double.MIN_NORMAL)</code>.
     */
    public static final int     MIN_EXPONENT    = -1022;

    /**
     * The exponent the smallest positive <code>double</code>
     * subnormal value would have if it could be normalized.  It is
     * equal to the value returned by
     * <code>FpUtils.ilogb(Double.MIN_VALUE)</code>.
     */
    public static final int     MIN_SUB_EXPONENT = MIN_EXPONENT -
                                                   (SIGNIFICAND_WIDTH - 1);

    /**
     * Bias used in representing a <code>double</code> exponent.
     */
    public static final int     EXP_BIAS        = 1023;

    /**
     * Bit mask to isolate the sign bit of a <code>double</code>.
     */
    public static final long    SIGN_BIT_MASK   = 0x8000000000000000L;

    /**
     * Bit mask to isolate the exponent field of a
     * <code>double</code>.
     */
    public static final long    EXP_BIT_MASK    = 0x7FF0000000000000L;

    /**
     * Bit mask to isolate the significand field of a
     * <code>double</code>.
     */
    public static final long    SIGNIF_BIT_MASK = 0x000FFFFFFFFFFFFFL;

    static {
        // verify bit masks cover all bit positions and that the bit
        // masks are non-overlapping
        assert(((SIGN_BIT_MASK | EXP_BIT_MASK | SIGNIF_BIT_MASK) == ~0L) &&
               (((SIGN_BIT_MASK & EXP_BIT_MASK) == 0L) &&
                ((SIGN_BIT_MASK & SIGNIF_BIT_MASK) == 0L) &&
                ((EXP_BIT_MASK & SIGNIF_BIT_MASK) == 0L)));
    }
}