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Java > Open Source Codes > org > pdfbox > filter > ASCIIHexFilter


1 /**
2  * Copyright (c) 2003, www.pdfbox.org
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions are met:
7  *
8  * 1. Redistributions of source code must retain the above copyright notice,
9  * this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright notice,
11  * this list of conditions and the following disclaimer in the documentation
12  * and/or other materials provided with the distribution.
13  * 3. Neither the name of pdfbox; nor the names of its
14  * contributors may be used to endorse or promote products derived from this
15  * software without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
18  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
20  * DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
21  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
22  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
23  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
24  * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
26  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27  *
28  * http://www.pdfbox.org
29  *
30  */
31 package org.pdfbox.filter;
32
33 import java.io.IOException JavaDoc;
34 import java.io.InputStream JavaDoc;
35 import java.io.OutputStream JavaDoc;
36
37 import org.pdfbox.cos.COSDictionary;
38
39 import org.pdfbox.persistence.util.COSHEXTable;
40
41 /**
42  * This is the used for the ASCIIHexDecode filter.
43  *
44  * @author <a HREF="mailto:ben@benlitchfield.com">Ben Litchfield</a>
45  * @version $Revision: 1.8 $
46  */
47 public class ASCIIHexFilter implements Filter
48 {
49
50     /**
51      * This will decode some compressed data.
52      *
53      * @param compressedData The compressed byte stream.
54      * @param result The place to write the uncompressed byte stream.
55      * @param options The options to use to encode the data.
56      *
57      * @throws IOException If there is an error decompressing the stream.
58      */
59     public void decode( InputStream JavaDoc compressedData, OutputStream JavaDoc result, COSDictionary options ) throws IOException JavaDoc
60     {
61         int value =0;
62         int firstByte = 0;
63         int secondByte = 0;
64         while( (firstByte = compressedData.read()) != -1 )
65         {
66             value = REVERSE_HEX[firstByte] * 16;
67             secondByte = compressedData.read();
68             if( secondByte >= 0 )
69             {
70                 value += REVERSE_HEX[ secondByte ];
71             }
72             result.write( value );
73         }
74         result.flush();
75     }
76
77     private static final int[] REVERSE_HEX =
78     {
79         -1, //0
80 -1, //1
81 -1, //2
82 -1, //3
83 -1, //4
84 -1, //5
85 -1, //6
86 -1, //7
87 -1, //8
88 -1, //9
89 -1, //10
90 -1, //11
91 -1, //12
92 -1, //13
93 -1, //14
94 -1, //15
95 -1, //16
96 -1, //17
97 -1, //18
98 -1, //19
99 -1, //20
100 -1, //21
101 -1, //22
102 -1, //23
103 -1, //24
104 -1, //25
105 -1, //26
106 -1, //27
107 -1, //28
108 -1, //29
109 -1, //30
110 -1, //31
111 -1, //32
112 -1, //33
113 -1, //34
114 -1, //35
115 -1, //36
116 -1, //37
117 -1, //38
118 -1, //39
119 -1, //40
120 -1, //41
121 -1, //42
122 -1, //43
123 -1, //44
124 -1, //45
125 -1, //46
126 -1, //47
127 0, //48
128 1, //49
129 2, //50
130 3, //51
131 4, //52
132 5, //53
133 6, //54
134 7, //55
135 8, //56
136 9, //57
137 -1, //58
138 -1, //59
139 -1, //60
140 -1, //61
141 -1, //62
142 -1, //63
143 -1, //64
144 10, //65
145 11, //66
146 12, //67
147 13, //68
148 14, //69
149 15, //70
150 -1, //71
151 -1, //72
152 -1, //73
153 -1, //74
154 -1, //75
155 -1, //76
156 -1, //77
157 -1, //78
158 -1, //79
159 -1, //80
160 -1, //81
161 -1, //82
162 -1, //83
163 -1, //84
164 -1, //85
165 -1, //86
166 -1, //87
167 -1, //88
168 -1, //89
169 -1, //90
170 -1, //91
171 -1, //92
172 -1, //93
173 -1, //94
174 -1, //95
175 -1, //96
176 10, //97
177 11, //98
178 12, //99
179 13, //100
180 14, //101
181 15, //102
182 };
183
184     /**
185      * This will encode some data.
186      *
187      * @param rawData The raw data to encode.
188      * @param result The place to write to encoded results to.
189      * @param options The options to use to encode the data.
190      *
191      * @throws IOException If there is an error compressing the stream.
192      */
193     public void encode( InputStream JavaDoc rawData, OutputStream JavaDoc result, COSDictionary options ) throws IOException JavaDoc
194     {
195         int byteRead = 0;
196         while( (byteRead = rawData.read()) != -1 )
197         {
198             int value = (byteRead+256)%256;
199             result.write( COSHEXTable.TABLE[value] );
200         }
201         result.flush();
202     }
203 }
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