1 /*
   2  * Copyright (c) 2000, 2018, 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  */
  24 
  25 package sun.jvm.hotspot.utilities;
  26 
  27 import java.io.*;
  28 import java.nio.charset.*;
  29 import java.util.*;
  30 
  31 import sun.jvm.hotspot.debugger.*;
  32 
  33 /** A utility class encapsulating useful operations on C strings
  34     represented as Addresses */
  35 
  36 public class CStringUtilities {
  37   /** Return the length of a null-terminated ASCII string in the
  38       remote process */
  39   public static int getStringLength(Address addr) {
  40     int i = 0;
  41     while (addr.getCIntegerAt(i, 1, false) != 0) {
  42       i++;
  43     }
  44     return i;
  45   }
  46 
  47   private static String encoding = System.getProperty("file.encoding", "US-ASCII");
  48 
  49   public static String getString(Address addr) {
  50     return getString(addr, Charset.forName(encoding));
  51   }
  52 
  53   /** Fetch a null-terminated ASCII string from the remote process.
  54       Returns null if the argument is null, otherwise returns a
  55       non-null string (for example, returns an empty string if the
  56       first character fetched is the null terminator). */
  57   public static String getString(Address addr, Charset charset) {
  58     if (addr == null) {
  59       return null;
  60     }
  61 
  62     List data = new ArrayList();
  63     byte val = 0;
  64     long i = 0;
  65     do {
  66       val = (byte) addr.getCIntegerAt(i, 1, false);
  67       if (val != 0) {
  68         data.add(new Byte(val));
  69       }
  70       ++i;
  71     } while (val != 0);
  72 
  73     // Convert to byte[] and from there to String
  74     byte[] bytes = new byte[data.size()];
  75     for (i = 0; i < data.size(); ++i) {
  76       bytes[(int) i] = ((Byte) data.get((int) i)).byteValue();
  77     }
  78     // FIXME: When we switch to use JDK 6 to build SA,
  79     // we can change the following to just return:
  80     // return new String(bytes, Charset.defaultCharset());
  81     return new String(bytes, charset);
  82   }
  83 }