1 /**
2 This file is part of GoldenGate Project (named also GoldenGate or GG).
3
4 Copyright 2009, Frederic Bregier, and individual contributors by the @author
5 tags. See the COPYRIGHT.txt in the distribution for a full listing of
6 individual contributors.
7
8 All GoldenGate Project is free software: you can redistribute it and/or
9 modify it under the terms of the GNU General Public License as published
10 by the Free Software Foundation, either version 3 of the License, or
11 (at your option) any later version.
12
13 GoldenGate is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
17
18 You should have received a copy of the GNU General Public License
19 along with GoldenGate . If not, see <http://www.gnu.org/licenses/>.
20 */
21 package goldengate.ftp.core.data.handler;
22
23 import org.jboss.netty.buffer.ChannelBuffer;
24
25 /**
26 * SeekAheadData Class used to optimize access to the incoming buffer
27 * @author Frederic Bregier
28 *
29 */
30 public class FtpSeekAheadData {
31 /**
32 * Exception when NO Backend Array is found
33 */
34 static class SeekAheadNoBackArrayException extends Exception {
35 private static final long serialVersionUID = -630418804938699495L;
36 }
37
38 byte[] bytes;
39
40 int readerIndex;
41
42 int pos;
43
44 int limit;
45
46 ChannelBuffer buffer;
47
48 /**
49 * @param buffer
50 */
51 FtpSeekAheadData(ChannelBuffer buffer) throws SeekAheadNoBackArrayException {
52 if (!buffer.hasArray()) {
53 throw new SeekAheadNoBackArrayException();
54 }
55 this.buffer = buffer;
56 this.bytes = buffer.array();
57 this.pos = this.readerIndex = buffer.readerIndex();
58 this.limit = buffer.writerIndex();
59 }
60
61 /**
62 *
63 * @param minus this value will be used as (currentPos - minus) to set
64 * the current readerIndex in the buffer.
65 */
66 void setReadPosition(int minus) {
67 pos -= minus;
68 readerIndex = pos;
69 buffer.readerIndex(readerIndex);
70 }
71
72 void clear() {
73 this.buffer = null;
74 this.bytes = null;
75 this.limit = 0;
76 this.pos = 0;
77 this.readerIndex = 0;
78 }
79 }