package java.lang;
/**
* Minimal Float implementation.
*
* @author Lawrie Griffiths
* @author Sven Köhler
*/
public final class Float extends Number
{
public static final float POSITIVE_INFINITY = 1.0f / 0.0f;
public static final float NEGATIVE_INFINITY = -1.0f / 0.0f;
public static final float NaN = 0.0f / 0.0f;
public static final int MAX_EXPONENT = 127;
public static final float MAX_VALUE = 0x1.fffffep+127f;
public static final int MIN_EXPONENT = -126;
public static final float MIN_NORMAL = 0x1.0p-126f;
public static final float MIN_VALUE = 0x1.0p-149f;
public static final int SIZE = 32;
// References to the following field are automatically replaced with a load
// of the correct value by the linker, so no need to initialize.
public static final Class<?> TYPE = null;
//MISSING implements Comparable
//MISSING public static int compare(float, float)
//MISSING public int compareTo(Object)
//MISSING public static String toHexString(float)
private float value;
public Float(double value)
{
this.value = (float)value;
}
/**
* Constructs a newly allocated Float object that represents the primitive float argument.
* @param value - the value to be represented by the Float.
*/
public Float(float value)
{
this.value = value;
}
public Float(String s)
{
this.value = Float.parseFloat(s);
}
@Override
public byte byteValue()
{
return (byte)this.value;
}
@Override
public double doubleValue()
{
return this.value;
}
@Override
public boolean equals(Object o)
{
//instanceof returns false for o==null
return (o instanceof Float)
&& (floatToIntBits(this.value) == floatToIntBits(((Float)o).value));
}
/**
* Returns the bit representation of a single-float value.
* The result is a representation of the floating-point argument
* according to the IEEE 754 floating-point "single
* precision" bit layout.
* <ul>
* <li>Bit 31 (the bit that is selected by the mask
* <code>0x80000000</code>) represents the sign of the floating-point
* number.
* <li>Bits 30-23 (the bits that are selected by the mask
* <code>0x7f800000</code>) represent the exponent.
* <li>Bits 22-0 (the bits that are selected by the mask
* <code>0x007fffff</code>) represent the significand (sometimes called
* the mantissa) of the floating-point number.
* <li>If the argument is positive infinity, the result is
* <code>0x7f800000</code>.
* <li>If the argument is negative infinity, the result is
* <code>0xff800000</code>.
* <p>
* If the argument is NaN, the result is the integer
* representing the actual NaN value.
* </ul>
* In all cases, the result is an integer that, when given to the
* {@link #intBitsToFloat(int)} method, will produce a floating-point
* value equal to the argument to <code>floatToRawIntBits</code>.
*
* @param value a floating-point number.
* @return the bits that represent the floating-point number.
*/
public static native int floatToRawIntBits(float value);
/**
* Returns the bit representation of a single-float value.
* The result is a representation of the floating-point argument
* according to the IEEE 754 floating-point "single
* precision" bit layout. Unlike <code>floatToRawIntBits</code> this
* method does collapse all NaN values into a standard single value. This
* value is <code>0x7fc00000</code>.
* @param value a floating-point number.
* @return the bits that represent the floating-point number.
*/
public static int floatToIntBits(float value)
{
int i = floatToRawIntBits(value);
// Collapse any NaN values
// Mask out the sign bit for the tests
int j = i & 0x7fffffff;
// and check for being in the NaN range
if (j >= 0x7f800001 && j <= 0x7fffffff)
i = 0x7fc00000;
return i;
}
/**
* Returns the float value of this Float object.
* @return the float value represented by this object
*/
@Override
public float floatValue()
{
return value;
}
@Override
public int hashCode()
{
return floatToIntBits(this.value);
}
/**
* Returns the single-float corresponding to a given bit represention.
* The argument is considered to be a representation of a
* floating-point value according to the IEEE 754 floating-point
* "single precision" bit layout.
* <p>
* If the argument is <code>0x7f800000</code>, the result is positive
* infinity.
* <p>
* If the argument is <code>0xff800000</code>, the result is negative
* infinity.
* <p>
* If the argument is any value in the range <code>0x7f800001</code>
* through <code>0x7fffffff</code> or in the range
* <code>0xff800001</code> through <code>0xffffffff</code>, the result is
* NaN. All IEEE 754 NaN values of type <code>float</code> are, in effect,
* lumped together by the Java programming language into a single
* <code>float</code> value called NaN. Distinct values of NaN are only
* accessible by use of the <code>Float.floatToRawIntBits</code> method.
* <p>
* In all other cases, let <i>s</i>, <i>e</i>, and <i>m</i> be three
* values that can be computed from the argument:
* <blockquote><pre>
* int s = ((bits >> 31) == 0) ? 1 : -1;
* int e = ((bits >> 23) & 0xff);
* int m = (e == 0) ?
* (bits & 0x7fffff) << 1 :
* (bits & 0x7fffff) | 0x800000;
* </pre></blockquote>
* Then the floating-point result equals the value of the mathematical
* expression <i>s·m·2<sup>e-150</sup></i>.
*
* @param value an integer.
* @return the single-format floating-point value with the same bit
* pattern.
*/
public static native float intBitsToFloat(int value);
@Override
public int intValue()
{
return (int)this.value;
}
public boolean isInfinite()
{
return Float.isInfinite(this.value);
}
public static boolean isInfinite(float v)
{
return v == POSITIVE_INFINITY || v == NEGATIVE_INFINITY;
}
public boolean isNaN()
{
return Float.isNaN(this.value);
}
public static boolean isNaN(float val)
{
return val != val;
}
@Override
public long longValue()
{
return (long)this.value;
}
/**
* Converts a String value into a float
* @param s String representation of float. Must only contain numbers and an optional decimal, and optional - sign at front.
* @return float number
*/
public static float parseFloat(String s) throws NumberFormatException
{
return StringUtils.stringToFloat(s);
}
@Override
public short shortValue()
{
return (short)this.value;
}
@Override
public String toString()
{
return String.valueOf(this.value);
}
/**
* Convert a float to a String
* @param f the float to be converted
* @return the String representation of the float
*/
public static String toString(float f)
{
return String.valueOf(f);
}
public static Float valueOf(float f)
{
return new Float(f);
}
public static Float valueOf(String s)
{
return new Float(s);
}
}