/**
 * Copyright 2017 Pivotal Software, 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 org.springframework.metrics.instrument.stats;

/**
 * Copied from https://github.com/mayconbordin/streaminer#quantiles
 */
public class PowerOfTwo {
    /**
     * Rounds the given value to the next power of two that is greater than the value.
     * @param value
     * @return
     */
    public static int ceilToNext(int value){
        Double powerOfTwo = Math.pow(2, Math.floor( Math.log10(value) / Math.log10(2) ));
        return powerOfTwo.intValue();
    }

    /**
     * Rounds the given value to the next power of two that is smaller than the value.
     * @param value
     * @return
     */
    public static Float floorToNext(Float value){
        Double powerOfTwo = Math.pow(2, Math.ceil( Math.log10(value) / Math.log10(2) ));
        return powerOfTwo.floatValue();
    }
    
    /**
     * Rounds the given value to the next power of two that is smaller than the value.
     * @param value
     * @return
     */
    public static double floorToNext(double value){
        return Math.pow(2, Math.ceil( Math.log10(value) / Math.log10(2) ));
    }
}
