1 /*
   2  * Copyright (c) 2015, 2015, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 package org.graalvm.compiler.word;
  24 
  25 /**
  26  * Utility methods on Unsigned values.
  27  */
  28 public final class UnsignedUtils {
  29 
  30     private UnsignedUtils() {
  31         // This is a class of static methods, so no need for any instances.
  32     }
  33 
  34     /**
  35      * Round an Unsigned down to the nearest smaller multiple.
  36      *
  37      * @param that The Unsigned to be rounded down.
  38      * @param multiple The multiple to which that Unsigned should be decreased.
  39      * @return That Unsigned, but rounded down.
  40      */
  41     public static Unsigned roundDown(Unsigned that, Unsigned multiple) {
  42         return that.unsignedDivide(multiple).multiply(multiple);
  43     }
  44 
  45     /**
  46      * Round an Unsigned up to the nearest larger multiple.
  47      *
  48      * @param that The Unsigned to be rounded up.
  49      * @param multiple The multiple to which that Unsigned should be increased.
  50      * @return That Unsigned, but rounded up.
  51      */
  52     public static Unsigned roundUp(Unsigned that, Unsigned multiple) {
  53         return UnsignedUtils.roundDown(that.add(multiple.subtract(1)), multiple);
  54     }
  55 
  56     /**
  57      * Check that an Unsigned is an even multiple.
  58      *
  59      * @param that The Unsigned to be verified as a multiple.
  60      * @param multiple The multiple against which the Unsigned should be verified.
  61      * @return true if that Unsigned is a multiple, false otherwise.
  62      */
  63     public static boolean isAMultiple(Unsigned that, Unsigned multiple) {
  64         return that.equal(UnsignedUtils.roundDown(that, multiple));
  65     }
  66 
  67     /**
  68      * The minimum of two Unsigneds.
  69      *
  70      * @param x An Unsigned.
  71      * @param y Another Unsigned.
  72      * @return The whichever Unsigned is smaller.
  73      */
  74     public static Unsigned min(Unsigned x, Unsigned y) {
  75         return (x.belowOrEqual(y)) ? x : y;
  76     }
  77 
  78     /**
  79      * The maximum of two Unsigneds.
  80      *
  81      * @param x An Unsigned.
  82      * @param y Another Unsigned.
  83      * @return The whichever Unsigned is larger.
  84      */
  85     public static Unsigned max(Unsigned x, Unsigned y) {
  86         return (x.aboveOrEqual(y)) ? x : y;
  87     }
  88 }