1 files changed, 176 insertions, 0 deletions
diff --git a/core/java/android/util/MathUtils.java b/core/java/android/util/MathUtils.java
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+++ b/core/java/android/util/MathUtils.java
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+/*
+ * Copyright (C) 2009 The Android Open Source Project
+ *
+ * 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 android.util;
+
+import java.util.Random;
+
+/**
+ * A class that contains utility methods related to numbers.
+ * 
+ * @hide Pending API council approval
+ */
+public final class MathUtils {
+    private static final Random sRandom = new Random();
+    private static final float DEG_TO_RAD = 3.1415926f / 180.0f;
+    private static final float RAD_TO_DEG = 180.0f / 3.1415926f;
+
+    private MathUtils() {
+    }
+
+    public static float abs(float v) {
+        return v > 0 ? v : -v; 
+    }
+
+    public static int constrain(int amount, int low, int high) {
+        return amount < low ? low : (amount > high ? high : amount);
+    }
+
+    public static float constrain(float amount, float low, float high) {
+        return amount < low ? low : (amount > high ? high : amount);
+    }
+
+    public static float log(float a) {
+        return (float) Math.log(a);
+    }
+
+    public static float exp(float a) {
+        return (float) Math.exp(a);
+    }
+
+    public static float pow(float a, float b) {
+        return (float) Math.pow(a, b);
+    }
+
+    public static float max(float a, float b) {
+        return a > b ? a : b;
+    }
+
+    public static float max(int a, int b) {
+        return a > b ? a : b;
+    }
+
+    public static float max(float a, float b, float c) {
+        return a > b ? (a > c ? a : c) : (b > c ? b : c);
+    }
+
+    public static float max(int a, int b, int c) {
+        return a > b ? (a > c ? a : c) : (b > c ? b : c);
+    }
+
+    public static float min(float a, float b) {
+        return a < b ? a : b;
+    }
+
+    public static float min(int a, int b) {
+        return a < b ? a : b;
+    }
+
+    public static float min(float a, float b, float c) {
+        return a < b ? (a < c ? a : c) : (b < c ? b : c);
+    }
+
+    public static float min(int a, int b, int c) {
+        return a < b ? (a < c ? a : c) : (b < c ? b : c);
+    }
+
+    public static float dist(float x1, float y1, float x2, float y2) {
+        final float x = (x2 - x1);
+        final float y = (y2 - y1);
+        return (float) Math.sqrt(x * x + y * y);
+    }
+
+    public static float dist(float x1, float y1, float z1, float x2, float y2, float z2) {
+        final float x = (x2 - x1);
+        final float y = (y2 - y1);
+        final float z = (z2 - z1);
+        return (float) Math.sqrt(x * x + y * y + z * z);
+    }
+
+    public static float mag(float a, float b) {
+        return (float) Math.sqrt(a * a + b * b);
+    }
+
+    public static float mag(float a, float b, float c) {
+        return (float) Math.sqrt(a * a + b * b + c * c);
+    }
+
+    public static float sq(float v) {
+        return v * v;
+    }
+
+    public static float radians(float degrees) {
+        return degrees * DEG_TO_RAD;
+    }
+
+    public static float degrees(float radians) {
+        return radians * RAD_TO_DEG;
+    }
+
+    public static float acos(float value) {
+        return (float) Math.acos(value);
+    }
+
+    public static float asin(float value) {
+        return (float) Math.asin(value);
+    }
+
+    public static float atan(float value) {
+        return (float) Math.atan(value);
+    }
+
+    public static float atan2(float a, float b) {
+        return (float) Math.atan2(a, b);
+    }
+
+    public static float tan(float angle) {
+        return (float) Math.tan(angle);
+    }    
+
+    public static float lerp(float start, float stop, float amount) {
+        return start + (stop - start) * amount;
+    }
+    
+    public static float norm(float start, float stop, float value) {
+        return (value - start) / (stop - start);
+    }
+    
+    public static float map(float minStart, float minStop, float maxStart, float maxStop, float value) {
+        return maxStart + (maxStart - maxStop) * ((value - minStart) / (minStop - minStart));
+    }
+
+    public static int random(int howbig) {
+        return (int) (sRandom.nextFloat() * howbig);
+    }
+
+    public static int random(int howsmall, int howbig) {
+        if (howsmall >= howbig) return howsmall;
+        return (int) (sRandom.nextFloat() * (howbig - howsmall) + howsmall);
+    }
+    
+    public static float random(float howbig) {
+        return sRandom.nextFloat() * howbig;
+    }
+
+    public static float random(float howsmall, float howbig) {
+        if (howsmall >= howbig) return howsmall;
+        return sRandom.nextFloat() * (howbig - howsmall) + howsmall;
+    }
+
+    public static void randomSeed(long seed) {
+        sRandom.setSeed(seed);
+    }
+}