org.eclipse.linuxtools.ctf.core/src/org/eclipse/linuxtools/ctf/core/trace/Utils.java

   1 /*******************************************************************************
   2  * Copyright (c) 2011-2012 Ericsson, Ecole Polytechnique de Montreal and others
   3  *
   4  * All rights reserved. This program and the accompanying materials are made
   5  * available under the terms of the Eclipse Public License v1.0 which
   6  * accompanies this distribution, and is available at
   7  * http://www.eclipse.org/legal/epl-v10.html
   8  *
   9  * Contributors: Matthew Khouzam - Initial API and implementation
  10  * Contributors: Simon Marchi - Initial API and implementation
  11  *******************************************************************************/
  12
  13 package org.eclipse.linuxtools.ctf.core.trace;
  14
  15 import java.util.UUID;
  16
  17 /**
  18  * Various utilities.
  19  *
  20  * @version 1.0
  21  * @author Matthew Khouzam
  22  * @author Simon Marchi
  23  */
  24 public class Utils {
  25
  26     // ------------------------------------------------------------------------
  27     // Constants
  28     // ------------------------------------------------------------------------
  29
  30     /**
  31      * CTF magic number. (sort of looks like CTF CTF CT)
  32      */
  33     public final static int CTF_MAGIC = 0xC1FC1FC1;
  34
  35     /**
  36      * TSDL magic number. (sort of looks like TSDL LSDT)
  37      */
  38     public final static int TSDL_MAGIC = 0x75D11D57;
  39
  40     /**
  41      * TSDL magic number length in bytes.
  42      */
  43     public final static int TSDL_MAGIC_LEN = 4;
  44
  45     /**
  46      * Directory separator on the current platform.
  47      */
  48     public final static String SEPARATOR = System.getProperty("file.separator"); //$NON-NLS-1$
  49
  50     /**
  51      * Length in bytes of a UUID value.
  52      */
  53     public final static int UUID_LEN = 16;
  54
  55     // ------------------------------------------------------------------------
  56     // Operations
  57     // ------------------------------------------------------------------------
  58
  59     /**
  60      * Unsigned long comparison.
  61      *
  62      * @param a
  63      *            First operand.
  64      * @param b
  65      *            Second operand.
  66      * @return -1 if a < b, 1 if a > b, 0 if a == b.
  67      */
  68     public static int unsignedCompare(long a, long b) {
  69         boolean aLeftBit = (a & (1 << (Long.SIZE - 1))) != 0;
  70         boolean bLeftBit = (b & (1 << (Long.SIZE - 1))) != 0;
  71
  72         if (aLeftBit && !bLeftBit) {
  73             return 1;
  74         } else if (!aLeftBit && bLeftBit) {
  75             return -1;
  76         } else {
  77             if (a < b) {
  78                 return -1;
  79             } else if (a > b) {
  80                 return 1;
  81             } else {
  82                 return 0;
  83             }
  84         }
  85     }
  86
  87     /**
  88      * Creates a UUID object from an array of 16 bytes.
  89      *
  90      * @param bytes
  91      *            Array of 16 bytes.
  92      * @return A UUID object.
  93      */
  94     public static UUID makeUUID(byte bytes[]) {
  95         long high = 0;
  96         long low = 0;
  97
  98         assert (bytes.length == Utils.UUID_LEN);
  99
 100         for (int i = 0; i < 8; i++) {
 101             low = (low << 8) | (bytes[i + 8] & 0xFF);
 102             high = (high << 8) | (bytes[i] & 0xFF);
 103         }
 104
 105         UUID uuid = new UUID(high, low);
 106
 107         return uuid;
 108     }
 109
 110 }