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

   1 /*******************************************************************************
   2  * Copyright (c) 2011, 2013 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.tracecompass.ctf.core.trace;
  14
  15 import java.util.UUID;
  16
  17 import org.eclipse.tracecompass.ctf.core.event.types.AbstractArrayDefinition;
  18 import org.eclipse.tracecompass.ctf.core.event.types.CompoundDeclaration;
  19 import org.eclipse.tracecompass.ctf.core.event.types.IDeclaration;
  20 import org.eclipse.tracecompass.ctf.core.event.types.IntegerDeclaration;
  21 import org.eclipse.tracecompass.ctf.core.event.types.IntegerDefinition;
  22
  23 /**
  24  * Various utilities.
  25  *
  26  * @version 1.0
  27  * @author Matthew Khouzam
  28  * @author Simon Marchi
  29  */
  30 public final class Utils {
  31
  32     private Utils() {
  33     }
  34
  35     // ------------------------------------------------------------------------
  36     // Constants
  37     // ------------------------------------------------------------------------
  38
  39     /**
  40      * CTF magic number. (sort of looks like CTF CTF CT)
  41      */
  42     public static final int CTF_MAGIC = 0xC1FC1FC1;
  43
  44     /**
  45      * TSDL magic number. (sort of looks like TSDL LSDT)
  46      */
  47     public static final int TSDL_MAGIC = 0x75D11D57;
  48
  49     /**
  50      * TSDL magic number length in bytes.
  51      */
  52     public static final int TSDL_MAGIC_LEN = 4;
  53
  54     /**
  55      * Directory separator on the current platform.
  56      */
  57     public static final String SEPARATOR = System.getProperty("file.separator"); //$NON-NLS-1$
  58
  59     /**
  60      * Length in bytes of a UUID value.
  61      */
  62     public static final int UUID_LEN = 16;
  63
  64     // ------------------------------------------------------------------------
  65     // Operations
  66     // ------------------------------------------------------------------------
  67
  68     /**
  69      * Performs an unsigned long comparison on two unsigned long numbers.
  70      *
  71      * <strong> As Java does not support unsigned types and arithmetic,
  72      * parameters are received encoded as a signed long (two-complement) but the
  73      * operation is an unsigned comparator.</strong>
  74      *
  75      * @param left
  76      *            Left operand of the comparator.
  77      * @param right
  78      *            Right operand of the comparator.
  79      * @return -1 if left &lt; right, 1 if left &gt; right, 0 if left == right.
  80      */
  81     public static int unsignedCompare(long left, long right) {
  82         /*
  83          * This method assumes that the arithmetic overflow on signed integer
  84          * wrap on a circular domain (modulo arithmetic in two-complement),
  85          * which is the defined behavior in Java.
  86          *
  87          * This idea is to rotate the domain by the length of the negative
  88          * space, and then use the signed operator.
  89          */
  90         final long a = left + Long.MIN_VALUE;
  91         final long b = right + Long.MIN_VALUE;
  92         if (a < b) {
  93             return -1;
  94         } else if (a > b) {
  95             return 1;
  96         }
  97         return 0;
  98     }
  99
 100     /**
 101      * Gets a UUID from an array defintion
 102      *
 103      * @param uuidDef
 104      *            the array defintions, must contain integer bytes
 105      * @return the UUID
 106      * @throws CTFReaderException
 107      *             if the definition contains less than 16 elements
 108      * @since 3.1
 109      */
 110     public static UUID getUUIDfromDefinition(AbstractArrayDefinition uuidDef) throws CTFReaderException {
 111         byte[] uuidArray = new byte[16];
 112         IDeclaration declaration = uuidDef.getDeclaration();
 113         if (!(declaration instanceof CompoundDeclaration)) {
 114             throw new CTFReaderException("UUID must be a sequence of unsigned bytes"); //$NON-NLS-1$
 115         }
 116         CompoundDeclaration uuidDec = (CompoundDeclaration) declaration;
 117
 118         IDeclaration uuidElem = uuidDec.getElementType();
 119         if (!(uuidElem instanceof IntegerDeclaration)) {
 120             throw new CTFReaderException("UUID must be a sequence of unsigned bytes"); //$NON-NLS-1$
 121         }
 122         IntegerDeclaration intUuidElem = (IntegerDeclaration) uuidElem;
 123         if (!intUuidElem.isUnsignedByte()) {
 124             throw new CTFReaderException("UUID must be a sequence of unsigned bytes"); //$NON-NLS-1$
 125         }
 126         return getUUID(uuidDef, uuidArray);
 127     }
 128
 129     private static UUID getUUID(AbstractArrayDefinition uuidDef, byte[] uuidArray) throws CTFReaderException {
 130         for (int i = 0; i < uuidArray.length; i++) {
 131             IntegerDefinition uuidByteDef = (IntegerDefinition) uuidDef.getDefinitions().get(i);
 132             if (uuidByteDef == null) {
 133                 throw new CTFReaderException("UUID incomplete, only " + i + " bytes available"); //$NON-NLS-1$ //$NON-NLS-2$
 134             }
 135             uuidArray[i] = (byte) uuidByteDef.getValue();
 136         }
 137
 138         UUID uuid = Utils.makeUUID(uuidArray);
 139         return uuid;
 140     }
 141
 142     /**
 143      * Gets a UUID from an array defintion
 144      *
 145      * @param uuidDef
 146      *            the array defintions, must contain integer bytes
 147      * @return the UUID
 148      * @throws CTFReaderException
 149      *             if the definition contains less than 16 elements
 150      * @since 3.1
 151      * @deprecated use
 152      *             {@link Utils#getUUIDfromDefinition(AbstractArrayDefinition uuidDef)}
 153      */
 154     @Deprecated
 155     public static UUID getUUIDfromDefinition(org.eclipse.tracecompass.ctf.core.event.types.ArrayDefinition uuidDef) throws CTFReaderException {
 156         byte[] uuidArray = new byte[16];
 157         return getUUID(uuidDef, uuidArray);
 158     }
 159
 160     /**
 161      * Creates a UUID object from an array of 16 bytes.
 162      *
 163      * @param bytes
 164      *            Array of 16 bytes.
 165      * @return A UUID object.
 166      */
 167     public static UUID makeUUID(byte bytes[]) {
 168         long high = 0;
 169         long low = 0;
 170
 171         assert (bytes.length == Utils.UUID_LEN);
 172
 173         for (int i = 0; i < 8; i++) {
 174             low = (low << 8) | (bytes[i + 8] & 0xFF);
 175             high = (high << 8) | (bytes[i] & 0xFF);
 176         }
 177
 178         UUID uuid = new UUID(high, low);
 179
 180         return uuid;
 181     }
 182
 183 }