ValueRepositoryId.java revision 608:7e06bf1dcb09 
1/*
2 * Copyright (c) 1999, 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.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25/*
26 * COMPONENT_NAME: idl.parser
27 *
28 * ORIGINS: 27
29 *
30 * Licensed Materials - Property of IBM
31 * 5639-D57 (C) COPYRIGHT International Business Machines Corp. 1997, 1999
32 * RMI-IIOP v1.0
33 *
34 */
35
36package com.sun.tools.corba.se.idl;
37
38// NOTES:
39
40import java.security.MessageDigest;
41import java.util.Hashtable;
42
43/**
44 *
45 **/
46public class ValueRepositoryId
47{
48  private MessageDigest sha;       // Message digest used to compute SHA-1
49  private int           index;     // Current index in the 'logical' sequence
50  private Hashtable     types;     // Already processed types
51  private String        hashcode;  // The computed hashcode
52
53  public ValueRepositoryId ()
54  {
55    try
56    {
57      sha = MessageDigest.getInstance ("SHA-1");
58    }
59    catch (Exception exception)
60    {}
61    index    = 0;
62    types    = new Hashtable ();
63    hashcode = null;
64  } // ctor
65
66  /**Add a value to the hashcode being computed.
67     @param value the value to be added to the value RepositoryID. */
68  public void addValue (int value)
69  {
70    sha.update ((byte)((value >> 24) & 0x0F));
71    sha.update ((byte)((value >> 16) & 0x0F));
72    sha.update ((byte)((value >>  8) & 0x0F));
73    sha.update ((byte)(value & 0x0F));
74    index++;
75  } // addValue
76
77  /** Add a type to the list of types which have already been included.
78      Note that the type should be added prior to its value.
79      @param entry the type to be added to the value RepositoryID. */
80  public void addType (SymtabEntry entry)
81  {
82    types.put (entry, new Integer (index));
83  }
84
85  /** Check to see if a specified type has already been processed. If so,
86      add the appropriate 'previously processed' code (0xFFFFFFFF) and
87      sequence offset, and return false; otherwise add the symbol table entry
88      and current offset to the hashtable and return false.
89      @param entry the type to be checked
90      @return true if the symbol table entry has not been previously added;
91       and false otherwise. */
92  public boolean isNewType (SymtabEntry entry)
93  {
94    Object index = types.get (entry);
95    if (index == null)
96    {
97      addType (entry);
98      return true;
99    }
100    addValue (0xFFFFFFFF);
101    addValue (((Integer)index).intValue ());
102    return false;
103  } // isNewType
104
105  /** Get the hashcode computed for the value type. This method MUST not be
106      called until all fields have been added, since it computes the hash
107      code from the values entered for each field.
108      @return the 64 bit hashcode for the value type represented as a
109       16 character hexadecimal string. */
110  public String getHashcode ()
111  {
112    if (hashcode == null)
113    {
114      byte [] digest = sha.digest ();
115      hashcode = hexOf (digest[0]) + hexOf (digest[1]) +
116                 hexOf (digest[2]) + hexOf (digest[3]) +
117                 hexOf (digest[4]) + hexOf (digest[5]) +
118                 hexOf (digest[6]) + hexOf (digest[7]);
119    }
120    return hashcode;
121  } // getHashCode
122
123  // Convert a byte to a two character hex string:
124  private static String hexOf (byte value)
125  {
126    int d1 = (value >> 4) & 0x0F;
127    int d2 = value & 0x0F;
128    return "0123456789ABCDEF".substring (d1, d1 + 1) +
129           "0123456789ABCDEF".substring (d2, d2 + 1);
130  } // hexOf
131} // class ValueRepositoryId
132