1 /* 2 * Copyright (C) 2007 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package android.util; 18 19 /** 20 * Math routines similar to those found in {@link java.lang.Math}. Performs 21 * computations on {@code float} values directly without incurring the overhead 22 * of conversions to and from {@code double}. 23 * 24 * <p>On one platform, {@code FloatMath.sqrt(100)} executes in one third of the 25 * time required by {@code java.lang.Math.sqrt(100)}.</p> 26 */ 27 public class FloatMath { 28 29 /** Prevents instantiation. */ FloatMath()30 private FloatMath() {} 31 32 /** 33 * Returns the float conversion of the most positive (i.e. closest to 34 * positive infinity) integer value which is less than the argument. 35 * 36 * @param value to be converted 37 * @return the floor of value 38 */ floor(float value)39 public static native float floor(float value); 40 41 /** 42 * Returns the float conversion of the most negative (i.e. closest to 43 * negative infinity) integer value which is greater than the argument. 44 * 45 * @param value to be converted 46 * @return the ceiling of value 47 */ ceil(float value)48 public static native float ceil(float value); 49 50 /** 51 * Returns the closest float approximation of the sine of the argument. 52 * 53 * @param angle to compute the cosine of, in radians 54 * @return the sine of angle 55 */ sin(float angle)56 public static native float sin(float angle); 57 58 /** 59 * Returns the closest float approximation of the cosine of the argument. 60 * 61 * @param angle to compute the cosine of, in radians 62 * @return the cosine of angle 63 */ cos(float angle)64 public static native float cos(float angle); 65 66 /** 67 * Returns the closest float approximation of the square root of the 68 * argument. 69 * 70 * @param value to compute sqrt of 71 * @return the square root of value 72 */ sqrt(float value)73 public static native float sqrt(float value); 74 75 /** 76 * Returns the closest float approximation of the raising "e" to the power 77 * of the argument. 78 * 79 * @param value to compute the exponential of 80 * @return the exponential of value 81 */ exp(float value)82 public static native float exp(float value); 83 84 /** 85 * Returns the closest float approximation of the result of raising {@code 86 * x} to the power of {@code y}. 87 * 88 * @param x the base of the operation. 89 * @param y the exponent of the operation. 90 * @return {@code x} to the power of {@code y}. 91 */ pow(float x, float y)92 public static native float pow(float x, float y); 93 94 /** 95 * Returns {@code sqrt(}<i>{@code x}</i><sup>{@code 2}</sup>{@code +} <i> 96 * {@code y}</i><sup>{@code 2}</sup>{@code )}. 97 * 98 * @param x a float number 99 * @param y a float number 100 * @return the hypotenuse 101 */ hypot(float x, float y)102 public static native float hypot(float x, float y); 103 } 104