org.eclipse.tracecompass.ctf.core/src/org/eclipse/linuxtools/ctf/core/event/types/StringDeclaration.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.linuxtools.ctf.core.event.types;
  14
  15 import org.eclipse.linuxtools.ctf.core.event.io.BitBuffer;
  16 import org.eclipse.linuxtools.ctf.core.event.scope.IDefinitionScope;
  17 import org.eclipse.linuxtools.ctf.core.trace.CTFReaderException;
  18
  19 /**
  20  * A CTF string declaration.
  21  *
  22  * Strings are an array of bytes of variable size and are terminated by a '\0'
  23  * "NULL" character. Their encoding is described in the TSDL meta-data. In
  24  * absence of encoding attribute information, the default encoding is UTF-8.
  25  *
  26  * @version 1.0
  27  * @author Matthew Khouzam
  28  * @author Simon Marchi
  29  */
  30 public class StringDeclaration extends Declaration {
  31
  32     // ------------------------------------------------------------------------
  33     // Attributes
  34     // ------------------------------------------------------------------------
  35
  36     private final Encoding fEncoding;
  37
  38     // ------------------------------------------------------------------------
  39     // Constructors
  40     // ------------------------------------------------------------------------
  41
  42     /**
  43      * Generate a UTF8 string declaration
  44      */
  45     public StringDeclaration() {
  46         fEncoding = Encoding.UTF8;
  47     }
  48
  49     /**
  50      * Generate an encoded string declaration
  51      * @param encoding the encoding, utf8 or ascii
  52      */
  53     public StringDeclaration(Encoding encoding) {
  54         fEncoding = encoding;
  55     }
  56
  57     // ------------------------------------------------------------------------
  58     // Getters/Setters/Predicates
  59     // ------------------------------------------------------------------------
  60
  61     /**
  62      *
  63      * @return the character encoding.
  64      */
  65     public Encoding getEncoding() {
  66         return fEncoding;
  67     }
  68
  69     @Override
  70     public long getAlignment() {
  71         // See ctf 4.2.5: Strings are always aligned on byte size.
  72         return 8;
  73     }
  74
  75     /**
  76      * @since 3.0
  77      */
  78     @Override
  79     public int getMaximumSize() {
  80         return Integer.MAX_VALUE;
  81     }
  82     // ------------------------------------------------------------------------
  83     // Operations
  84     // ------------------------------------------------------------------------
  85
  86     /**
  87      * @since 3.0
  88      */
  89     @Override
  90     public StringDefinition createDefinition(IDefinitionScope definitionScope,
  91             String fieldName, BitBuffer input) throws CTFReaderException {
  92         String value = read(input);
  93         return new StringDefinition(this, definitionScope, fieldName, value);
  94     }
  95
  96     private String read(BitBuffer input) throws CTFReaderException {
  97         /* Offset the buffer position wrt the current alignment */
  98         alignRead(input);
  99
 100         StringBuilder sb = new StringBuilder();
 101         char c = (char) input.get(8, false);
 102         while (c != 0) {
 103             sb.append(c);
 104             c = (char) input.get(8, false);
 105         }
 106         return sb.toString();
 107     }
 108     @Override
 109     public String toString() {
 110         /* Only used for debugging */
 111         return "[declaration] string[" + Integer.toHexString(hashCode()) + ']'; //$NON-NLS-1$
 112     }
 113
 114 }