/*
* Copyright 2008 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package java.lang;
/**
* Wraps a primitive <code>float</code> as an object.
*/
public final class Float extends Number implements Comparable<Float> {
public static final float MAX_VALUE = 3.4028235e+38f;
public static final float MIN_VALUE = 1.4e-45f;
public static final float MAX_EXPONENT = 127;
public static final float MIN_EXPONENT = -126;
public static final float MIN_NORMAL = 1.1754943508222875E-38f;
public static final float NaN = 0f / 0f;
public static final float NEGATIVE_INFINITY = -1f / 0f;
public static final float POSITIVE_INFINITY = 1f / 0f;
public static final int SIZE = 32;
private static final long POWER_31_INT = 2147483648L;
private static final long POWER_32_INT = 4294967296L;
public static int compare(float x, float y) {
if (x < y) {
return -1;
} else if (x > y) {
return 1;
} else {
return 0;
}
}
public static int floatToIntBits(float value) {
// Return a canonical NaN
if (isNaN(value)) {
return 0x7fc00000;
}
if (value == 0.0f) {
if (1.0 / value == NEGATIVE_INFINITY) {
return 0x80000000; // -0.0f
} else {
return 0x0;
}
}
boolean negative = false;
if (value < 0.0) {
negative = true;
value = -value;
}
if (isInfinite(value)) {
if (negative) {
return 0xff800000;
} else {
return 0x7f800000;
}
}
// Obtain the 64-bit representation and extract its exponent and
// mantissa.
long l = Double.doubleToLongBits((double) value);
int exp = (int) (((l >> 52) & 0x7ff) - 1023);
int mantissa = (int) ((l & 0xfffffffffffffL) >> 29);
// If the number will be a denorm in the float representation
// (i.e., its exponent is -127 or smaller), add a leading 1 to the
// mantissa and shift it right to maintain an exponent of -127.
if (exp <= -127) {
mantissa = (0x800000 | mantissa) >> (-127 - exp + 1);
exp = -127;
}
// Construct the 32-bit representation
long bits = negative ? POWER_31_INT : 0x0L;
bits |= (exp + 127) << 23;
bits |= mantissa;
return (int) bits;
}
/**
* @skip Here for shared implementation with Arrays.hashCode.
* @param f
* @return hash value of float (currently just truncated to int)
*/
public static int hashCode(float f) {
return (int) f;
}
public static float intBitsToFloat(int bits) {
boolean negative = (bits & 0x80000000) != 0;
int exp = (bits >> 23) & 0xff;
bits &= 0x7fffff;
if (exp == 0x0) {
// Handle +/- 0 here, denorms below
if (bits == 0) {
return negative ? -0.0f : 0.0f;
}
} else if (exp == 0xff) {
// Inf & NaN
if (bits == 0) {
return negative ? NEGATIVE_INFINITY : POSITIVE_INFINITY;
} else {
return NaN;
}
}
if (exp == 0) {
// Input is denormalized, renormalize by shifting left until there is a
// leading 1
exp = 1;
while ((bits & 0x800000) == 0) {
bits <<= 1;
exp--;
}
bits &= 0x7fffff;
}
// Build the bits of a 64-bit double from the incoming bits
long bits64 = negative ? 0x8000000000000000L : 0x0L;
bits64 |= ((long) (exp + 896)) << 52;
bits64 |= ((long) bits) << 29;
return (float) Double.longBitsToDouble(bits64);
}
public static native boolean isInfinite(float x) /*-{
return !isFinite(x);
}-*/;
public static native boolean isNaN(float x) /*-{
return isNaN(x);
}-*/;
public static float parseFloat(String s) throws NumberFormatException {
double doubleValue = __parseAndValidateDouble(s);
if (doubleValue > Float.MAX_VALUE) {
return Float.POSITIVE_INFINITY;
} else if (doubleValue < -Float.MAX_VALUE) {
return Float.NEGATIVE_INFINITY;
}
return (float) doubleValue;
}
public static String toString(float b) {
return String.valueOf(b);
}
public static Float valueOf(float f) {
return new Float(f);
}
public static Float valueOf(String s) throws NumberFormatException {
return new Float(Float.parseFloat(s));
}
private final transient float value;
public Float(double value) {
this.value = (float) value;
}
public Float(float value) {
this.value = value;
}
public Float(String s) {
value = parseFloat(s);
}
@Override
public byte byteValue() {
return (byte) value;
}
public int compareTo(Float b) {
if (value < b.value) {
return -1;
} else if (value > b.value) {
return 1;
} else {
return 0;
}
}
@Override
public double doubleValue() {
return value;
}
@Override
public boolean equals(Object o) {
return (o instanceof Float) && (((Float) o).value == value);
}
@Override
public float floatValue() {
return value;
}
/**
* Performance caution: using Float objects as map keys is not recommended.
* Using floating point values as keys is generally a bad idea due to
* difficulty determining exact equality. In addition, there is no efficient
* JavaScript equivalent of <code>floatToIntBits</code>. As a result, this
* method computes a hash code by truncating the whole number portion of the
* float, which may lead to poor performance for certain value sets if Floats
* are used as keys in a {@link java.util.HashMap}.
*/
@Override
public int hashCode() {
return hashCode(value);
}
@Override
public int intValue() {
return (int) value;
}
public boolean isInfinite() {
return isInfinite(value);
}
public boolean isNaN() {
return isNaN(value);
}
@Override
public long longValue() {
return (long) value;
}
@Override
public short shortValue() {
return (short) value;
}
@Override
public String toString() {
return toString(value);
}
}