1 //******************************************************************************
2 //
3 // File: ByteArrayBuf_1.java
4 // Package: edu.rit.mp.buf
5 // Unit: Class edu.rit.mp.buf.ByteArrayBuf_1
6 //
7 // This Java source file is copyright (C) 2007 by Alan Kaminsky. All rights
8 // reserved. For further information, contact the author, Alan Kaminsky, at
9 // ark@cs.rit.edu.
10 //
11 // This Java source file is part of the Parallel Java Library ("PJ"). PJ is free
12 // software; you can redistribute it and/or modify it under the terms of the GNU
13 // General Public License as published by the Free Software Foundation; either
14 // version 3 of the License, or (at your option) any later version.
15 //
16 // PJ is distributed in the hope that it will be useful, but WITHOUT ANY
17 // WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
18 // A PARTICULAR PURPOSE. See the GNU General Public License for more details.
19 //
20 // Linking this library statically or dynamically with other modules is making a
21 // combined work based on this library. Thus, the terms and conditions of the GNU
22 // General Public License cover the whole combination.
23 //
24 // As a special exception, the copyright holders of this library give you
25 // permission to link this library with independent modules to produce an
26 // executable, regardless of the license terms of these independent modules, and
27 // to copy and distribute the resulting executable under terms of your choice,
28 // provided that you also meet, for each linked independent module, the terms
29 // and conditions of the license of that module. An independent module is a module
30 // which is not derived from or based on this library. If you modify this library,
31 // you may extend this exception to your version of the library, but you are not
32 // obligated to do so. If you do not wish to do so, delete this exception
33 // statement from your version.
34 //
35 // A copy of the GNU General Public License is provided in the file gpl.txt. You
36 // may also obtain a copy of the GNU General Public License on the World Wide
37 // Web at http://www.gnu.org/licenses/gpl.html.
38 //
39 //******************************************************************************
40 package edu.rit.mp.buf;
41
42 import java.nio.ByteBuffer;
43
44 import edu.rit.mp.Buf;
45 import edu.rit.pj.reduction.ByteOp;
46 import edu.rit.pj.reduction.Op;
47 import edu.rit.util.Range;
48
49 /**
50 * Class ByteArrayBuf_1 provides a buffer for an array of byte items sent or
51 * received using the Message Protocol (MP). The array element stride must be 1.
52 * While an instance of class ByteArrayBuf may be constructed directly, normally
53 * you will use a factory method in class {@linkplain edu.rit.mp.ByteBuf
54 * ByteBuf}. See that class for further information.
55 *
56 * @author Alan Kaminsky
57 * @version 25-Oct-2007
58 */
59 public class ByteArrayBuf_1
60 extends ByteArrayBuf {
61
62 // Exported constructors.
63 /**
64 * Construct a new byte array buffer.
65 *
66 * @param theArray Array.
67 * @param theRange Range of array elements to include in the buffer. The
68 * stride is assumed to be 1.
69 */
70 public ByteArrayBuf_1(byte[] theArray,
71 Range theRange) {
72 super(theArray, theRange);
73 }
74
75 // Exported operations.
76 /**
77 * {@inheritDoc}
78 *
79 * Obtain the given item from this buffer.
80 * <P>
81 * The <code>get()</code> method must not block the calling thread; if it does,
82 * all message I/O in MP will be blocked.
83 */
84 public byte get(int i) {
85 return myArray[myArrayOffset + i];
86 }
87
88 /**
89 * {@inheritDoc}
90 *
91 * Store the given item in this buffer.
92 * <P>
93 * The <code>put()</code> method must not block the calling thread; if it does,
94 * all message I/O in MP will be blocked.
95 */
96 public void put(int i,
97 byte item) {
98 myArray[myArrayOffset + i] = item;
99 }
100
101 /**
102 * {@inheritDoc}
103 *
104 * Create a buffer for performing parallel reduction using the given binary
105 * operation. The results of the reduction are placed into this buffer.
106 * @exception ClassCastException (unchecked exception) Thrown if this
107 * buffer's element data type and the given binary operation's argument data
108 * type are not the same.
109 */
110 public Buf getReductionBuf(Op op) {
111 return new ByteArrayReductionBuf_1(myArray, myRange, (ByteOp) op);
112 }
113
114 // Hidden operations.
115 /**
116 * {@inheritDoc}
117 *
118 * Send as many items as possible from this buffer to the given byte buffer.
119 * <P>
120 * The <code>sendItems()</code> method must not block the calling thread; if it
121 * does, all message I/O in MP will be blocked.
122 */
123 protected int sendItems(int i,
124 ByteBuffer buffer) {
125 int n = Math.min(myLength - i, buffer.remaining());
126 buffer.put(myArray, myArrayOffset + i, n);
127 return n;
128 }
129
130 /**
131 * {@inheritDoc}
132 *
133 * Receive as many items as possible from the given byte buffer to this
134 * buffer.
135 * <P>
136 * The <code>receiveItems()</code> method must not block the calling thread; if
137 * it does, all message I/O in MP will be blocked.
138 */
139 protected int receiveItems(int i,
140 int num,
141 ByteBuffer buffer) {
142 int n = Math.min(num, Math.min(myLength - i, buffer.remaining()));
143 buffer.get(myArray, myArrayOffset + i, n);
144 return n;
145 }
146
147 }