| /* |
| * 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 int MAX_EXPONENT = 127; |
| public static final int 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; |
| public static final int BYTES = SIZE / Byte.SIZE; |
| public static final Class<Float> TYPE = float.class; |
| |
| private static final long POWER_31_INT = 2147483648L; |
| |
| public static int compare(float x, float y) { |
| return Double.compare(x, y); |
| } |
| |
| 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; |
| } |
| |
| /** |
| * @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 boolean isFinite(float x) { |
| return Double.isFinite(x); |
| } |
| |
| public static boolean isInfinite(float x) { |
| return Double.isInfinite(x); |
| } |
| |
| public static boolean isNaN(float x) { |
| return Double.isNaN(x); |
| } |
| |
| public static float max(float a, float b) { |
| return Math.max(a, b); |
| } |
| |
| public static float min(float a, float b) { |
| return Math.min(a, b); |
| } |
| |
| 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 float sum(float a, float b) { |
| return a + b; |
| } |
| |
| 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(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; |
| } |
| |
| @Override |
| public int compareTo(Float b) { |
| return compare(value, b.value); |
| } |
| |
| @Override |
| public double doubleValue() { |
| return value; |
| } |
| |
| @Override |
| public boolean equals(Object o) { |
| // Make sure Float follow the same semantic as Double for consistency. |
| return (o instanceof Float) && Double.valueOf(value).equals(Double.valueOf(((Float) o).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); |
| } |
| |
| } |