Here you can find the source of roundUpToPowerOfTwo(int v)
public static int roundUpToPowerOfTwo(int v)
//package com.java2s; /***** BEGIN LICENSE BLOCK ***** * Version: EPL 1.0/GPL 2.0/LGPL 2.1/*from w w w . jav a 2 s.c o m*/ * * The contents of this file are subject to the Eclipse Public * License Version 1.0 (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.eclipse.org/legal/epl-v10.html * * Software distributed under the License is distributed on an "AS * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or * implied. See the License for the specific language governing * rights and limitations under the License. * * Copyright (C) 2008 JRuby project * * Alternatively, the contents of this file may be used under the terms of * either of the GNU General Public License Version 2 or later (the "GPL"), * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"), * in which case the provisions of the GPL or the LGPL are applicable instead * of those above. If you wish to allow use of your version of this file only * under the terms of either the GPL or the LGPL, and not to allow others to * use your version of this file under the terms of the EPL, indicate your * decision by deleting the provisions above and replace them with the notice * and other provisions required by the GPL or the LGPL. If you do not delete * the provisions above, a recipient may use your version of this file under * the terms of any one of the EPL, the GPL or the LGPL. ***** END LICENSE BLOCK *****/ public class Main { public static int roundUpToPowerOfTwo(int v) { if (v < 1) return 1; v--; v |= v >> 1; v |= v >> 2; v |= v >> 4; v |= v >> 8; v |= v >> 16; return v + 1; } }