1    
2    /* ====================================================================
3     * The Apache Software License, Version 1.1
4     *
5     * Copyright (c) 2002 The Apache Software Foundation.  All rights
6     * reserved.
7     *
8     * Redistribution and use in source and binary forms, with or without
9     * modification, are permitted provided that the following conditions
10    * are met:
11    *
12    * 1. Redistributions of source code must retain the above copyright
13    *    notice, this list of conditions and the following disclaimer.
14    *
15    * 2. Redistributions in binary form must reproduce the above copyright
16    *    notice, this list of conditions and the following disclaimer in
17    *    the documentation and/or other materials provided with the
18    *    distribution.
19    *
20    * 3. The end-user documentation included with the redistribution,
21    *    if any, must include the following acknowledgment:
22    *       "This product includes software developed by the
23    *        Apache Software Foundation (http://www.apache.org/)."
24    *    Alternately, this acknowledgment may appear in the software itself,
25    *    if and wherever such third-party acknowledgments normally appear.
26    *
27    * 4. The names "Apache" and "Apache Software Foundation" and
28    *    "Apache POI" must not be used to endorse or promote products
29    *    derived from this software without prior written permission. For
30    *    written permission, please contact apache@apache.org.
31    *
32    * 5. Products derived from this software may not be called "Apache",
33    *    "Apache POI", nor may "Apache" appear in their name, without
34    *    prior written permission of the Apache Software Foundation.
35    *
36    * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
37    * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
38    * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
39    * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
40    * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
41    * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
42    * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
43    * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
44    * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
45    * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
46    * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
47    * SUCH DAMAGE.
48    * ====================================================================
49    *
50    * This software consists of voluntary contributions made by many
51    * individuals on behalf of the Apache Software Foundation.  For more
52    * information on the Apache Software Foundation, please see
53    * <http://www.apache.org/>.
54    */
55   
56   package org.apache.poi.util;
57   
58   import org.apache.poi.util.LittleEndian.BufferUnderrunException;
59   
60   import java.io.*;
61   
62   /**
63    * representation of an integer (32-bit) field at a fixed location
64    * within a byte array
65    *
66    * @author Marc Johnson (mjohnson at apache dot org
67    */
68   
69   public class IntegerField
70       implements FixedField
71   {
72       private int       _value;
73       private final int _offset;
74   
75       /**
76        * construct the IntegerField with its offset into its containing
77        * byte array
78        *
79        * @param offset of the field within its byte array
80        *
81        * @exception ArrayIndexOutOfBoundsException if the offset is
82        *            negative
83        */
84   
85       public IntegerField(final int offset)
86           throws ArrayIndexOutOfBoundsException
87       {
88           if (offset < 0)
89           {
90               throw new ArrayIndexOutOfBoundsException("negative offset");
91           }
92           _offset = offset;
93       }
94   
95       /**
96        * construct the IntegerField with its offset into its containing
97        * byte array and initialize its value
98        *
99        * @param offset of the field within its byte array
100       * @param value the initial value
101       *
102       * @exception ArrayIndexOutOfBoundsException if the offset is
103       *            negative
104       */
105  
106      public IntegerField(final int offset, final int value)
107          throws ArrayIndexOutOfBoundsException
108      {
109          this(offset);
110          set(value);
111      }
112  
113      /**
114       * Construct the IntegerField with its offset into its containing
115       * byte array and initialize its value from its byte array
116       *
117       * @param offset of the field within its byte array
118       * @param data the byte array to read the value from
119       *
120       * @exception ArrayIndexOutOfBoundsException if the offset is not
121       *            within the range of 0..(data.length - 1)
122       */
123  
124      public IntegerField(final int offset, final byte [] data)
125          throws ArrayIndexOutOfBoundsException
126      {
127          this(offset);
128          readFromBytes(data);
129      }
130  
131      /**
132       * construct the IntegerField with its offset into its containing
133       * byte array, initialize its value, and write the value to a byte
134       * array
135       *
136       * @param offset of the field within its byte array
137       * @param value the initial value
138       * @param data the byte array to write the value to
139       *
140       * @exception ArrayIndexOutOfBoundsException if the offset is
141       *            negative or too large
142       */
143  
144      public IntegerField(final int offset, final int value, final byte [] data)
145          throws ArrayIndexOutOfBoundsException
146      {
147          this(offset);
148          set(value, data);
149      }
150  
151      /**
152       * get the IntegerField's current value
153       *
154       * @return current value
155       */
156  
157      public int get()
158      {
159          return _value;
160      }
161  
162      /**
163       * set the IntegerField's current value
164       *
165       * @param value to be set
166       */
167  
168      public void set(final int value)
169      {
170          _value = value;
171      }
172  
173      /**
174       * set the IntegerField's current value and write it to a byte
175       * array
176       *
177       * @param value to be set
178       * @param data the byte array to write the value to
179       *
180       * @exception ArrayIndexOutOfBoundsException if the offset is too
181       *            large
182       */
183  
184      public void set(final int value, final byte [] data)
185          throws ArrayIndexOutOfBoundsException
186      {
187          _value = value;
188          writeToBytes(data);
189      }
190  
191      /* ********** START implementation of FixedField ********** */
192  
193      /**
194       * set the value from its offset into an array of bytes
195       *
196       * @param data the byte array from which the value is to be read
197       *
198       * @exception ArrayIndexOutOfBoundsException if the offset is too
199       *            large
200       */
201  
202      public void readFromBytes(final byte [] data)
203          throws ArrayIndexOutOfBoundsException
204      {
205          _value = LittleEndian.getInt(data, _offset);
206      }
207  
208      /**
209       * set the value from an InputStream
210       *
211       * @param stream the InputStream from which the value is to be
212       *               read
213       *
214       * @exception BufferUnderrunException if there is not enough data
215       *            available from the InputStream
216       * @exception IOException if an IOException is thrown from reading
217       *            the InputStream
218       */
219  
220      public void readFromStream(final InputStream stream)
221          throws IOException, BufferUnderrunException
222      {
223          _value = LittleEndian.readInt(stream);
224      }
225  
226      /**
227       * write the value out to an array of bytes at the appropriate
228       * offset
229       *
230       * @param data the array of bytes to which the value is to be
231       *             written
232       *
233       * @exception ArrayIndexOutOfBoundsException if the offset is too
234       *            large
235       */
236  
237      public void writeToBytes(final byte [] data)
238          throws ArrayIndexOutOfBoundsException
239      {
240          LittleEndian.putInt(data, _offset, _value);
241      }
242  
243      /**
244       * return the value as a String
245       *
246       * @return the value as a String
247       */
248  
249      public String toString()
250      {
251          return String.valueOf(_value);
252      }
253  
254      /* **********  END  implementation of FixedField ********** */
255  }   // end public class IntegerField
256  
257