7804c0bcf93e4e16560eec58f9a83a404dee5667
[sonitus.git] / src / main / java / net / pterodactylus / sonitus / io / IntegralWriteOutputStream.java
1 /*
2  * Sonitus - IntegralWriteOutputStream.java - Copyright © 2013 David Roden
3  *
4  * This program is free software: you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License as published by
6  * the Free Software Foundation, either version 3 of the License, or
7  * (at your option) any later version.
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
16  */
17
18 package net.pterodactylus.sonitus.io;
19
20 import java.io.FilterOutputStream;
21 import java.io.IOException;
22 import java.io.OutputStream;
23
24 /**
25  * {@link OutputStream} wrapper that always writes a multiple of a fixed amount
26  * of bytes at once.
27  *
28  * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
29  */
30 public class IntegralWriteOutputStream extends FilterOutputStream {
31
32         /** The current in-process values. */
33         private final byte[] buffer;
34
35         /** The next position of the buffer that will be written to. */
36         private int bufferPosition;
37
38         /**
39          * Creates a new integral write output stream.
40          *
41          * @param outputStream
42          *              The output stream to wrap
43          * @param integralSize
44          *              The number of bytes to write at once
45          */
46         public IntegralWriteOutputStream(OutputStream outputStream, int integralSize) {
47                 super(outputStream);
48                 buffer = new byte[integralSize];
49         }
50
51         //
52         // OUTPUTSTREAM METHODS
53         //
54
55         @Override
56         public void write(int data) throws IOException {
57                 buffer[bufferPosition++] = (byte) data;
58                 if (bufferPosition == buffer.length) {
59                         bufferPosition = 0;
60                         out.write(buffer);
61                 }
62         }
63
64         @Override
65         public void write(byte[] buffer) throws IOException {
66                 write(buffer, 0, buffer.length);
67         }
68
69         @Override
70         public void write(byte[] buffer, int offset, int length) throws IOException {
71                 /* are the some bytes in the current buffer? */
72                 int sourceOffset = 0;
73                 if (bufferPosition != 0) {
74                         int bytesToCopy = Math.min(length, this.buffer.length - bufferPosition);
75                         System.arraycopy(buffer, offset, this.buffer, bufferPosition, bytesToCopy);
76                         sourceOffset += bytesToCopy;
77                         bufferPosition += bytesToCopy;
78                         if (bufferPosition == this.buffer.length) {
79                                 bufferPosition = 0;
80                                 out.write(this.buffer);
81                         }
82                 }
83
84                 /* write the largest possible chunk at once. */
85                 int integralBytesLeft = (int) ((length - sourceOffset) / this.buffer.length) * this.buffer.length;
86                 if (integralBytesLeft != 0) {
87                         out.write(buffer, offset + sourceOffset, integralBytesLeft);
88                 }
89
90                 /* are there some bytes left? */
91                 sourceOffset += integralBytesLeft;
92                 if (sourceOffset < length) {
93                         System.arraycopy(buffer, offset + sourceOffset, this.buffer, 0, length - sourceOffset);
94                         bufferPosition = length - sourceOffset;
95                 }
96         }
97
98 }