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1   /*
2    * $Id: Abbreviations.java,v 1.3 2005/09/28 16:36:15 weiju Exp $
3    * 
4    * Created on 25.09.2005
5    * Copyright 2005 by Wei-ju Wu
6    *
7    * This file is part of The Z-machine Preservation Project (ZMPP).
8    *
9    * ZMPP is free software; you can redistribute it and/or modify
10   * it under the terms of the GNU General Public License as published by
11   * the Free Software Foundation; either version 2 of the License, or
12   * (at your option) any later version.
13   *
14   * ZMPP is distributed in the hope that it will be useful,
15   * but WITHOUT ANY WARRANTY; without even the implied warranty of
16   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17   * GNU General Public License for more details.
18   *
19   * You should have received a copy of the GNU General Public License
20   * along with ZMPP; if not, write to the Free Software
21   * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
22   */
23  package org.zmpp.vm;
24  
25  import org.zmpp.base.MemoryReadAccess;
26  import org.zmpp.vmutil.ZsciiConverter.AbbreviationsTable;
27  
28  /***
29   * This class represents a view to the abbreviations table. The table
30   * starts at the predefined address within the header and contains pointers
31   * to ZSCII strings in the memory map. These pointers are word addresses
32   * as opposed to all other addresses in the memory map, therefore the
33   * actual value has to multiplied by two to get the real address.
34   *
35   * @author Wei-ju Wu
36   * @version 1.0
37   */
38  public class Abbreviations implements AbbreviationsTable {
39  
40    /***
41     * The memory map.
42     */
43    private MemoryReadAccess map;
44    
45    /***
46     * The start address of the abbreviations table.
47     */
48    private int address;
49    
50    /***
51     * Constructor.
52     * 
53     * @param map the memory map
54     * @param address the start address of the abbreviations table
55     */
56    public Abbreviations(MemoryReadAccess map, int address) {
57      
58      this.map = map;
59      this.address = address;
60    }
61    
62    /***
63     * The abbreviation table contains word addresses, so read out the pointer
64     * and multiply by two
65     * 
66     * @param entryNum the entry index in the abbreviations table
67     * @return the word address
68     */
69    public int getWordAddress(int entryNum) {
70      
71      return map.readUnsignedShort(address + entryNum * 2) * 2;
72    }  
73  }