1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.pdfbox.filter;
18
19 import java.io.IOException;
20 import java.io.InputStream;
21 import java.io.OutputStream;
22
23 import org.apache.pdfbox.cos.COSDictionary;
24
25 import org.apache.pdfbox.persistence.util.COSHEXTable;
26
27 /**
28 * This is the used for the ASCIIHexDecode filter.
29 *
30 * @author <a href="mailto:ben@benlitchfield.com">Ben Litchfield</a>
31 * @version $Revision: 1.9 $
32 */
33 public class ASCIIHexFilter implements Filter
34 {
35
36 /**
37 * Whitespace.
38 * 0 0x00 Null (NUL)
39 * 9 0x09 Tab (HT)
40 * 10 0x0A Line feed (LF)
41 * 12 0x0C Form feed (FF)
42 * 13 0x0D Carriage return (CR)
43 * 32 0x20 Space (SP)
44 */
45
46 private boolean isWhitespace(int c)
47 {
48 return c == 0 || c == 9 || c == 10 || c == 12 || c == 13 || c == 32;
49 }
50
51 private boolean isEOD(int c)
52 {
53 return (c == 62); // '>' - EOD
54 }
55
56 /**
57 * {@inheritDoc}
58 */
59 public void decode( InputStream compressedData, OutputStream result, COSDictionary options, int filterIndex )
60 throws IOException
61 {
62 int value = 0;
63 int firstByte = 0;
64 int secondByte = 0;
65 while ((firstByte = compressedData.read()) != -1)
66 {
67 // always after first char
68 while(isWhitespace(firstByte))
69 {
70 firstByte = compressedData.read();
71 }
72 if(isEOD(firstByte))
73 {
74 break;
75 }
76
77 if(REVERSE_HEX[firstByte] == -1)
78 {
79 System.out.println("Invalid Hex Code; int: " + firstByte + " char: " + (char) firstByte);
80 }
81 value = REVERSE_HEX[firstByte] * 16;
82 secondByte = compressedData.read();
83
84 if(isEOD(secondByte))
85 {
86 // second value behaves like 0 in case of EOD
87 result.write( value );
88 break;
89 }
90 if(secondByte >= 0)
91 {
92 if(REVERSE_HEX[secondByte] == -1)
93 {
94 System.out.println("Invalid Hex Code; int: " + secondByte + " char: " + (char) secondByte);
95 }
96 value += REVERSE_HEX[secondByte];
97 }
98 result.write( value );
99 }
100 result.flush();
101 }
102
103 private static final int[] REVERSE_HEX =
104 {
105 -1, //0
106 -1, //1
107 -1, //2
108 -1, //3
109 -1, //4
110 -1, //5
111 -1, //6
112 -1, //7
113 -1, //8
114 -1, //9
115 -1, //10
116 -1, //11
117 -1, //12
118 -1, //13
119 -1, //14
120 -1, //15
121 -1, //16
122 -1, //17
123 -1, //18
124 -1, //19
125 -1, //20
126 -1, //21
127 -1, //22
128 -1, //23
129 -1, //24
130 -1, //25
131 -1, //26
132 -1, //27
133 -1, //28
134 -1, //29
135 -1, //30
136 -1, //31
137 -1, //32
138 -1, //33
139 -1, //34
140 -1, //35
141 -1, //36
142 -1, //37
143 -1, //38
144 -1, //39
145 -1, //40
146 -1, //41
147 -1, //42
148 -1, //43
149 -1, //44
150 -1, //45
151 -1, //46
152 -1, //47
153 0, //48
154 1, //49
155 2, //50
156 3, //51
157 4, //52
158 5, //53
159 6, //54
160 7, //55
161 8, //56
162 9, //57
163 -1, //58
164 -1, //59
165 -1, //60
166 -1, //61
167 -1, //62
168 -1, //63
169 -1, //64
170 10, //65
171 11, //66
172 12, //67
173 13, //68
174 14, //69
175 15, //70
176 -1, //71
177 -1, //72
178 -1, //73
179 -1, //74
180 -1, //75
181 -1, //76
182 -1, //77
183 -1, //78
184 -1, //79
185 -1, //80
186 -1, //81
187 -1, //82
188 -1, //83
189 -1, //84
190 -1, //85
191 -1, //86
192 -1, //87
193 -1, //88
194 -1, //89
195 -1, //90
196 -1, //91
197 -1, //92
198 -1, //93
199 -1, //94
200 -1, //95
201 -1, //96
202 10, //97
203 11, //98
204 12, //99
205 13, //100
206 14, //101
207 15, //102
208 };
209
210 /**
211 * {@inheritDoc}
212 */
213 public void encode( InputStream rawData, OutputStream result, COSDictionary options, int filterIndex )
214 throws IOException
215 {
216 int byteRead = 0;
217 while( (byteRead = rawData.read()) != -1 )
218 {
219 int value = (byteRead+256)%256;
220 result.write( COSHEXTable.TABLE[value] );
221 }
222 result.flush();
223 }
224 }