From c8875fb97fc03779a5bba09872227b1d08e5d52a Mon Sep 17 00:00:00 2001 From: tromey Date: Sat, 16 Jul 2005 00:30:23 +0000 Subject: Initial revision git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@102074 138bc75d-0d04-0410-961f-82ee72b054a4 --- 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 00000000000..e6200dabddc --- /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 Float represent primitive + * float 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 double may represent + * is 3.4028235e+38f. + */ + public static final float MAX_VALUE = 3.4028235e+38f; + + /** + * The minimum positive value a float 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 float is represented by this + * Class 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 Float from the primitive float + * specified. + * + * @param value the float argument + */ + public Float(float value) + { + this.value = value; + } + + /** + * Create a Float from the primitive double + * specified. + * + * @param value the double argument + */ + public Float(double value) + { + this.value = (float) value; + } + + /** + * Create a Float from the specified String. + * This method calls Float.parseFloat(). + * + * @param s the String to convert + * @throws NumberFormatException if s cannot be parsed as a + * float + * @throws NullPointerException if s is null + * @see #parseFloat(String) + */ + public Float(String s) + { + value = parseFloat(s); + } + + /** + * Convert the float to a String. + * Floating-point string representation is fairly complex: here is a + * rundown of the possible values. "[-]" indicates that a + * negative sign will be printed if the value (or exponent) is negative. + * "<number>" means a string of digits ('0' to '9'). + * "<digit>" means a single digit ('0' to '9').
+ * + * + * + * + * + * + * + * + * + * + *
Value of FloatString Representation
[+-] 0 [-]0.0
Between [+-] 10-3 and 107, exclusive[-]number.number
Other numeric value[-]<digit>.<number> + * E[-]<number>
[+-] infinity [-]Infinity
NaN NaN
+ * + * Yes, negative zero is a possible value. Note that there is + * always a . and at least one digit printed after + * it: even if the number is 3, it will be printed as 3.0. + * 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. + * + *

To create other output formats, use {@link java.text.NumberFormat}. + * + * @XXX specify where we are not in accord with the spec. + * + * @param f the float to convert + * @return the String representing the float + */ + public static String toString(float f) + { + return VMDouble.toString(f, true); + } + + /** + * Creates a new Float object using the String. + * + * @param s the String to convert + * @return the new Float + * @throws NumberFormatException if s cannot be parsed as a + * float + * @throws NullPointerException if s is null + * @see #parseFloat(String) + */ + public static Float valueOf(String s) + { + return new Float(parseFloat(s)); + } + + /** + * Parse the specified String as a float. The + * extended BNF grammar is as follows:
+ * 

+   * DecodableString:
+   *      ( [ - | + ] NaN )
+   *    | ( [ - | + ] Infinity )
+   *    | ( [ - | + ] FloatingPoint
+   *              [ f | F | d
+   *                | D] )
+   * FloatingPoint:
+   *      ( { Digit }+ [ . { Digit } ]
+   *              [ Exponent ] )
+   *    | ( . { Digit }+ [ Exponent ] )
+   * Exponent:
+   *      ( ( e | E )
+   *              [ - | + ] { Digit }+ )
+   * Digit: '0' through '9'
+   *
+ * + *

NaN and infinity are special cases, to allow parsing of the output + * of toString. Otherwise, the result is determined by calculating + * n * 10exponent 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. + * + *

If an unexpected character is found in the String, a + * NumberFormatException will be thrown. Leading and trailing + * 'whitespace' is ignored via String.trim(), but spaces + * internal to the actual number are not allowed. + * + *

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 String to convert + * @return the float value of s + * @throws NumberFormatException if s cannot be parsed as a + * float + * @throws NullPointerException if s 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 true if the float has the same + * value as NaN, otherwise return false. + * + * @param v the float to compare + * @return whether the argument is NaN + */ + public static boolean isNaN(float v) + { + // This works since NaN != NaN is the only reflexive inequality + // comparison which returns true. + return v != v; + } + + /** + * Return true if the float has a value + * equal to either NEGATIVE_INFINITY or + * POSITIVE_INFINITY, otherwise return false. + * + * @param v the float to compare + * @return whether the argument is (-/+) infinity + */ + public static boolean isInfinite(float v) + { + return v == POSITIVE_INFINITY || v == NEGATIVE_INFINITY; + } + + /** + * Return true if the value of this Float + * is the same as NaN, otherwise return false. + * + * @return whether this Float is NaN + */ + public boolean isNaN() + { + return isNaN(value); + } + + /** + * Return true if the value of this Float + * is the same as NEGATIVE_INFINITY or + * POSITIVE_INFINITY, otherwise return false. + * + * @return whether this Float is (-/+) infinity + */ + public boolean isInfinite() + { + return isInfinite(value); + } + + /** + * Convert the float value of this Float + * to a String. This method calls + * Float.toString(float) to do its dirty work. + * + * @return the String representation + * @see #toString(float) + */ + public String toString() + { + return toString(value); + } + + /** + * Return the value of this Float as a byte. + * + * @return the byte value + * @since 1.1 + */ + public byte byteValue() + { + return (byte) value; + } + + /** + * Return the value of this Float as a short. + * + * @return the short value + * @since 1.1 + */ + public short shortValue() + { + return (short) value; + } + + /** + * Return the value of this Integer as an int. + * + * @return the int value + */ + public int intValue() + { + return (int) value; + } + + /** + * Return the value of this Integer as a long. + * + * @return the long value + */ + public long longValue() + { + return (long) value; + } + + /** + * Return the value of this Float. + * + * @return the float value + */ + public float floatValue() + { + return value; + } + + /** + * Return the value of this Float as a double + * + * @return the double value + */ + public double doubleValue() + { + return value; + } + + /** + * Return a hashcode representing this Object. Float's hash + * code is calculated by calling floatToIntBits(floatValue()). + * + * @return this Object's hash code + * @see #floatToIntBits(float) + */ + public int hashCode() + { + return floatToIntBits(value); + } + + /** + * Returns true if obj is an instance of + * Float and represents the same float value. Unlike comparing + * two floats with ==, this treats two instances of + * Float.NaN as equal, but treats 0.0 and + * -0.0 as unequal. + * + *

Note that f1.equals(f2) is identical to + * floatToIntBits(f1.floatValue()) == + * floatToIntBits(f2.floatValue()). + * + * @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 Float.intBitsToFloat(int) to obtain the + * original float value. + * + * @param value the float to convert + * @return the bits of the float + * @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 Float.intBitsToFloat(int) to + * obtain the original float value. + * + * @param value the float to convert + * @return the bits of the float + * @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 + * Float.floatToRawIntBits(float). + * + * @param bits the bits to convert + * @return the float 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 float + * 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 POSITIVE_INFINITY, 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 compareTo(Float) unless the Object + * is not an Float. + * + * @param o the object to compare + * @return the comparison + * @throws ClassCastException if the argument is not a Float + * @see #compareTo(Float) + * @see Comparable + * @since 1.2 + */ + public int compareTo(Object o) + { + return compare(value, ((Float) o).value); + } + + /** + * Behaves like new Float(x).compareTo(new Float(y)); 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; + } +} -- cgit v1.2.3