From f911ba985aa7fe0096c386c5be385ac5825ea527 Mon Sep 17 00:00:00 2001
From: Tom Tromey <tromey@gcc.gnu.org>
Date: Sat, 16 Jul 2005 00:30:23 +0000
Subject: Initial revision
From-SVN: r102074
---
libjava/classpath/java/lang/Float.java | 527 +++++++++++++++++++++++++++++++++
1 file changed, 527 insertions(+)
create mode 100644 libjava/classpath/java/lang/Float.java
(limited to 'libjava/classpath/java/lang/Float.java')
diff --git a/libjava/classpath/java/lang/Float.java b/libjava/classpath/java/lang/Float.java
new file mode 100644
index 0000000..e6200da
--- /dev/null
+++ b/libjava/classpath/java/lang/Float.java
@@ -0,0 +1,527 @@
+/* Float.java -- object wrapper for float
+ Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2005
+ Free Software Foundation, Inc.
+
+This file is part of GNU Classpath.
+
+GNU Classpath is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU Classpath is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; see the file COPYING. If not, write to the
+Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library. Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module. An independent module is a module which is not derived from
+or based on this library. If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so. If you do not wish to do so, delete this
+exception statement from your version. */
+
+
+package java.lang;
+
+/**
+ * Instances of class <code>Float</code> represent primitive
+ * <code>float</code> values.
+ *
+ * Additionally, this class provides various helper functions and variables
+ * related to floats.
+ *
+ * @author Paul Fisher
+ * @author Andrew Haley (aph@cygnus.com)
+ * @author Eric Blake (ebb9@email.byu.edu)
+ * @since 1.0
+ * @status updated to 1.4
+ */
+public final class Float extends Number implements Comparable
+{
+ /**
+ * Compatible with JDK 1.0+.
+ */
+ private static final long serialVersionUID = -2671257302660747028L;
+
+ /**
+ * The maximum positive value a <code>double</code> may represent
+ * is 3.4028235e+38f.
+ */
+ public static final float MAX_VALUE = 3.4028235e+38f;
+
+ /**
+ * The minimum positive value a <code>float</code> may represent
+ * is 1.4e-45.
+ */
+ public static final float MIN_VALUE = 1.4e-45f;
+
+ /**
+ * The value of a float representation -1.0/0.0, negative infinity.
+ */
+ public static final float NEGATIVE_INFINITY = -1.0f / 0.0f;
+
+ /**
+ * The value of a float representation 1.0/0.0, positive infinity.
+ */
+ public static final float POSITIVE_INFINITY = 1.0f / 0.0f;
+
+ /**
+ * All IEEE 754 values of NaN have the same value in Java.
+ */
+ public static final float NaN = 0.0f / 0.0f;
+
+ /**
+ * The primitive type <code>float</code> is represented by this
+ * <code>Class</code> object.
+ * @since 1.1
+ */
+ public static final Class TYPE = VMClassLoader.getPrimitiveClass('F');
+
+ /**
+ * The immutable value of this Float.
+ *
+ * @serial the wrapped float
+ */
+ private final float value;
+
+ /**
+ * Create a <code>Float</code> from the primitive <code>float</code>
+ * specified.
+ *
+ * @param value the <code>float</code> argument
+ */
+ public Float(float value)
+ {
+ this.value = value;
+ }
+
+ /**
+ * Create a <code>Float</code> from the primitive <code>double</code>
+ * specified.
+ *
+ * @param value the <code>double</code> argument
+ */
+ public Float(double value)
+ {
+ this.value = (float) value;
+ }
+
+ /**
+ * Create a <code>Float</code> from the specified <code>String</code>.
+ * This method calls <code>Float.parseFloat()</code>.
+ *
+ * @param s the <code>String</code> to convert
+ * @throws NumberFormatException if <code>s</code> cannot be parsed as a
+ * <code>float</code>
+ * @throws NullPointerException if <code>s</code> is null
+ * @see #parseFloat(String)
+ */
+ public Float(String s)
+ {
+ value = parseFloat(s);
+ }
+
+ /**
+ * Convert the <code>float</code> to a <code>String</code>.
+ * Floating-point string representation is fairly complex: here is a
+ * rundown of the possible values. "<code>[-]</code>" indicates that a
+ * negative sign will be printed if the value (or exponent) is negative.
+ * "<code><number></code>" means a string of digits ('0' to '9').
+ * "<code><digit></code>" means a single digit ('0' to '9').<br>
+ *
+ * <table border=1>
+ * <tr><th>Value of Float</th><th>String Representation</th></tr>
+ * <tr><td>[+-] 0</td> <td><code>[-]0.0</code></td></tr>
+ * <tr><td>Between [+-] 10<sup>-3</sup> and 10<sup>7</sup>, exclusive</td>
+ * <td><code>[-]number.number</code></td></tr>
+ * <tr><td>Other numeric value</td>
+ * <td><code>[-]<digit>.<number>
+ * E[-]<number></code></td></tr>
+ * <tr><td>[+-] infinity</td> <td><code>[-]Infinity</code></td></tr>
+ * <tr><td>NaN</td> <td><code>NaN</code></td></tr>
+ * </table>
+ *
+ * Yes, negative zero <em>is</em> a possible value. Note that there is
+ * <em>always</em> a <code>.</code> and at least one digit printed after
+ * it: even if the number is 3, it will be printed as <code>3.0</code>.
+ * After the ".", all digits will be printed except trailing zeros. The
+ * result is rounded to the shortest decimal number which will parse back
+ * to the same float.
+ *
+ * <p>To create other output formats, use {@link java.text.NumberFormat}.
+ *
+ * @XXX specify where we are not in accord with the spec.
+ *
+ * @param f the <code>float</code> to convert
+ * @return the <code>String</code> representing the <code>float</code>
+ */
+ public static String toString(float f)
+ {
+ return VMDouble.toString(f, true);
+ }
+
+ /**
+ * Creates a new <code>Float</code> object using the <code>String</code>.
+ *
+ * @param s the <code>String</code> to convert
+ * @return the new <code>Float</code>
+ * @throws NumberFormatException if <code>s</code> cannot be parsed as a
+ * <code>float</code>
+ * @throws NullPointerException if <code>s</code> is null
+ * @see #parseFloat(String)
+ */
+ public static Float valueOf(String s)
+ {
+ return new Float(parseFloat(s));
+ }
+
+ /**
+ * Parse the specified <code>String</code> as a <code>float</code>. The
+ * extended BNF grammar is as follows:<br>
+ * <pre>
+ * <em>DecodableString</em>:
+ * ( [ <code>-</code> | <code>+</code> ] <code>NaN</code> )
+ * | ( [ <code>-</code> | <code>+</code> ] <code>Infinity</code> )
+ * | ( [ <code>-</code> | <code>+</code> ] <em>FloatingPoint</em>
+ * [ <code>f</code> | <code>F</code> | <code>d</code>
+ * | <code>D</code>] )
+ * <em>FloatingPoint</em>:
+ * ( { <em>Digit</em> }+ [ <code>.</code> { <em>Digit</em> } ]
+ * [ <em>Exponent</em> ] )
+ * | ( <code>.</code> { <em>Digit</em> }+ [ <em>Exponent</em> ] )
+ * <em>Exponent</em>:
+ * ( ( <code>e</code> | <code>E</code> )
+ * [ <code>-</code> | <code>+</code> ] { <em>Digit</em> }+ )
+ * <em>Digit</em>: <em><code>'0'</code> through <code>'9'</code></em>
+ * </pre>
+ *
+ * <p>NaN and infinity are special cases, to allow parsing of the output
+ * of toString. Otherwise, the result is determined by calculating
+ * <em>n * 10<sup>exponent</sup></em> to infinite precision, then rounding
+ * to the nearest float. Remember that many numbers cannot be precisely
+ * represented in floating point. In case of overflow, infinity is used,
+ * and in case of underflow, signed zero is used. Unlike Integer.parseInt,
+ * this does not accept Unicode digits outside the ASCII range.
+ *
+ * <p>If an unexpected character is found in the <code>String</code>, a
+ * <code>NumberFormatException</code> will be thrown. Leading and trailing
+ * 'whitespace' is ignored via <code>String.trim()</code>, but spaces
+ * internal to the actual number are not allowed.
+ *
+ * <p>To parse numbers according to another format, consider using
+ * {@link java.text.NumberFormat}.
+ *
+ * @XXX specify where/how we are not in accord with the spec.
+ *
+ * @param str the <code>String</code> to convert
+ * @return the <code>float</code> value of <code>s</code>
+ * @throws NumberFormatException if <code>s</code> cannot be parsed as a
+ * <code>float</code>
+ * @throws NullPointerException if <code>s</code> is null
+ * @see #MIN_VALUE
+ * @see #MAX_VALUE
+ * @see #POSITIVE_INFINITY
+ * @see #NEGATIVE_INFINITY
+ * @since 1.2
+ */
+ public static float parseFloat(String str)
+ {
+ // XXX Rounding parseDouble() causes some errors greater than 1 ulp from
+ // the infinitely precise decimal.
+ return (float) Double.parseDouble(str);
+ }
+
+ /**
+ * Return <code>true</code> if the <code>float</code> has the same
+ * value as <code>NaN</code>, otherwise return <code>false</code>.
+ *
+ * @param v the <code>float</code> to compare
+ * @return whether the argument is <code>NaN</code>
+ */
+ public static boolean isNaN(float v)
+ {
+ // This works since NaN != NaN is the only reflexive inequality
+ // comparison which returns true.
+ return v != v;
+ }
+
+ /**
+ * Return <code>true</code> if the <code>float</code> has a value
+ * equal to either <code>NEGATIVE_INFINITY</code> or
+ * <code>POSITIVE_INFINITY</code>, otherwise return <code>false</code>.
+ *
+ * @param v the <code>float</code> to compare
+ * @return whether the argument is (-/+) infinity
+ */
+ public static boolean isInfinite(float v)
+ {
+ return v == POSITIVE_INFINITY || v == NEGATIVE_INFINITY;
+ }
+
+ /**
+ * Return <code>true</code> if the value of this <code>Float</code>
+ * is the same as <code>NaN</code>, otherwise return <code>false</code>.
+ *
+ * @return whether this <code>Float</code> is <code>NaN</code>
+ */
+ public boolean isNaN()
+ {
+ return isNaN(value);
+ }
+
+ /**
+ * Return <code>true</code> if the value of this <code>Float</code>
+ * is the same as <code>NEGATIVE_INFINITY</code> or
+ * <code>POSITIVE_INFINITY</code>, otherwise return <code>false</code>.
+ *
+ * @return whether this <code>Float</code> is (-/+) infinity
+ */
+ public boolean isInfinite()
+ {
+ return isInfinite(value);
+ }
+
+ /**
+ * Convert the <code>float</code> value of this <code>Float</code>
+ * to a <code>String</code>. This method calls
+ * <code>Float.toString(float)</code> to do its dirty work.
+ *
+ * @return the <code>String</code> representation
+ * @see #toString(float)
+ */
+ public String toString()
+ {
+ return toString(value);
+ }
+
+ /**
+ * Return the value of this <code>Float</code> as a <code>byte</code>.
+ *
+ * @return the byte value
+ * @since 1.1
+ */
+ public byte byteValue()
+ {
+ return (byte) value;
+ }
+
+ /**
+ * Return the value of this <code>Float</code> as a <code>short</code>.
+ *
+ * @return the short value
+ * @since 1.1
+ */
+ public short shortValue()
+ {
+ return (short) value;
+ }
+
+ /**
+ * Return the value of this <code>Integer</code> as an <code>int</code>.
+ *
+ * @return the int value
+ */
+ public int intValue()
+ {
+ return (int) value;
+ }
+
+ /**
+ * Return the value of this <code>Integer</code> as a <code>long</code>.
+ *
+ * @return the long value
+ */
+ public long longValue()
+ {
+ return (long) value;
+ }
+
+ /**
+ * Return the value of this <code>Float</code>.
+ *
+ * @return the float value
+ */
+ public float floatValue()
+ {
+ return value;
+ }
+
+ /**
+ * Return the value of this <code>Float</code> as a <code>double</code>
+ *
+ * @return the double value
+ */
+ public double doubleValue()
+ {
+ return value;
+ }
+
+ /**
+ * Return a hashcode representing this Object. <code>Float</code>'s hash
+ * code is calculated by calling <code>floatToIntBits(floatValue())</code>.
+ *
+ * @return this Object's hash code
+ * @see #floatToIntBits(float)
+ */
+ public int hashCode()
+ {
+ return floatToIntBits(value);
+ }
+
+ /**
+ * Returns <code>true</code> if <code>obj</code> is an instance of
+ * <code>Float</code> and represents the same float value. Unlike comparing
+ * two floats with <code>==</code>, this treats two instances of
+ * <code>Float.NaN</code> as equal, but treats <code>0.0</code> and
+ * <code>-0.0</code> as unequal.
+ *
+ * <p>Note that <code>f1.equals(f2)</code> is identical to
+ * <code>floatToIntBits(f1.floatValue()) ==
+ * floatToIntBits(f2.floatValue())</code>.
+ *
+ * @param obj the object to compare
+ * @return whether the objects are semantically equal
+ */
+ public boolean equals(Object obj)
+ {
+ if (! (obj instanceof Float))
+ return false;
+
+ float f = ((Float) obj).value;
+
+ // Avoid call to native method. However, some implementations, like gcj,
+ // are better off using floatToIntBits(value) == floatToIntBits(f).
+ // Check common case first, then check NaN and 0.
+ if (value == f)
+ return (value != 0) || (1 / value == 1 / f);
+ return isNaN(value) && isNaN(f);
+ }
+
+ /**
+ * Convert the float to the IEEE 754 floating-point "single format" bit
+ * layout. Bit 31 (the most significant) is the sign bit, bits 30-23
+ * (masked by 0x7f800000) represent the exponent, and bits 22-0
+ * (masked by 0x007fffff) are the mantissa. This function collapses all
+ * versions of NaN to 0x7fc00000. The result of this function can be used
+ * as the argument to <code>Float.intBitsToFloat(int)</code> to obtain the
+ * original <code>float</code> value.
+ *
+ * @param value the <code>float</code> to convert
+ * @return the bits of the <code>float</code>
+ * @see #intBitsToFloat(int)
+ */
+ public static int floatToIntBits(float value)
+ {
+ return VMFloat.floatToIntBits(value);
+ }
+
+ /**
+ * Convert the float to the IEEE 754 floating-point "single format" bit
+ * layout. Bit 31 (the most significant) is the sign bit, bits 30-23
+ * (masked by 0x7f800000) represent the exponent, and bits 22-0
+ * (masked by 0x007fffff) are the mantissa. This function leaves NaN alone,
+ * rather than collapsing to a canonical value. The result of this function
+ * can be used as the argument to <code>Float.intBitsToFloat(int)</code> to
+ * obtain the original <code>float</code> value.
+ *
+ * @param value the <code>float</code> to convert
+ * @return the bits of the <code>float</code>
+ * @see #intBitsToFloat(int)
+ */
+ public static int floatToRawIntBits(float value)
+ {
+ return VMFloat.floatToRawIntBits(value);
+ }
+
+ /**
+ * Convert the argument in IEEE 754 floating-point "single format" bit
+ * layout to the corresponding float. Bit 31 (the most significant) is the
+ * sign bit, bits 30-23 (masked by 0x7f800000) represent the exponent, and
+ * bits 22-0 (masked by 0x007fffff) are the mantissa. This function leaves
+ * NaN alone, so that you can recover the bit pattern with
+ * <code>Float.floatToRawIntBits(float)</code>.
+ *
+ * @param bits the bits to convert
+ * @return the <code>float</code> represented by the bits
+ * @see #floatToIntBits(float)
+ * @see #floatToRawIntBits(float)
+ */
+ public static float intBitsToFloat(int bits)
+ {
+ return VMFloat.intBitsToFloat(bits);
+ }
+
+ /**
+ * Compare two Floats numerically by comparing their <code>float</code>
+ * values. The result is positive if the first is greater, negative if the
+ * second is greater, and 0 if the two are equal. However, this special
+ * cases NaN and signed zero as follows: NaN is considered greater than
+ * all other floats, including <code>POSITIVE_INFINITY</code>, and positive
+ * zero is considered greater than negative zero.
+ *
+ * @param f the Float to compare
+ * @return the comparison
+ * @since 1.2
+ */
+ public int compareTo(Float f)
+ {
+ return compare(value, f.value);
+ }
+
+ /**
+ * Behaves like <code>compareTo(Float)</code> unless the Object
+ * is not an <code>Float</code>.
+ *
+ * @param o the object to compare
+ * @return the comparison
+ * @throws ClassCastException if the argument is not a <code>Float</code>
+ * @see #compareTo(Float)
+ * @see Comparable
+ * @since 1.2
+ */
+ public int compareTo(Object o)
+ {
+ return compare(value, ((Float) o).value);
+ }
+
+ /**
+ * Behaves like <code>new Float(x).compareTo(new Float(y))</code>; in
+ * other words this compares two floats, special casing NaN and zero,
+ * without the overhead of objects.
+ *
+ * @param x the first float to compare
+ * @param y the second float to compare
+ * @return the comparison
+ * @since 1.4
+ */
+ public static int compare(float x, float y)
+ {
+ if (isNaN(x))
+ return isNaN(y) ? 0 : 1;
+ if (isNaN(y))
+ return -1;
+ // recall that 0.0 == -0.0, so we convert to infinities and try again
+ if (x == 0 && y == 0)
+ return (int) (1 / x - 1 / y);
+ if (x == y)
+ return 0;
+
+ return x > y ? 1 : -1;
+ }
+}
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