1 //******************************************************************************
2 //
3 // File: Unsigned16BitIntegerItemBuf.java
4 // Package: edu.rit.mp.buf
5 // Unit: Class edu.rit.mp.buf.Unsigned16BitIntegerItemBuf
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.mp.Unsigned16BitIntegerBuf;
46 import edu.rit.pj.reduction.IntegerOp;
47 import edu.rit.pj.reduction.Op;
48
49 /**
50 * Class Unsigned16BitIntegerItemBuf provides a buffer for a single unsigned
51 * 16-bit integer item sent or received using the Message Protocol (MP). While
52 * an instance of class Unsigned16BitIntegerItemBuf may be constructed directly,
53 * normally you will use a factory method in class {@linkplain
54 * edu.rit.mp.Unsigned16BitIntegerBuf Unsigned16BitIntegerBuf}. See that class
55 * for further information.
56 *
57 * @author Alan Kaminsky
58 * @version 26-Oct-2007
59 */
60 public class Unsigned16BitIntegerItemBuf
61 extends Unsigned16BitIntegerBuf {
62
63 // Exported data members.
64 /**
65 * Integer item to be sent or received.
66 */
67 public int item;
68
69 // Exported constructors.
70 /**
71 * Construct a new unsigned 16-bit integer item buffer.
72 */
73 public Unsigned16BitIntegerItemBuf() {
74 super(1);
75 }
76
77 /**
78 * Construct a new unsigned 16-bit integer item buffer with the given
79 * initial value.
80 *
81 * @param item Initial value of the {@link #item} field.
82 */
83 public Unsigned16BitIntegerItemBuf(int item) {
84 super(1);
85 this.item = item;
86 }
87
88 // Exported operations.
89 /**
90 * {@inheritDoc}
91 *
92 * Obtain the given item from this buffer.
93 * <P>
94 * The <code>get()</code> method must not block the calling thread; if it does,
95 * all message I/O in MP will be blocked.
96 */
97 public int get(int i) {
98 return this.item;
99 }
100
101 /**
102 * {@inheritDoc}
103 *
104 * Store the given item in this buffer.
105 * <P>
106 * The <code>put()</code> method must not block the calling thread; if it does,
107 * all message I/O in MP will be blocked.
108 */
109 public void put(int i,
110 int item) {
111 this.item = item;
112 }
113
114 /**
115 * {@inheritDoc}
116 *
117 * Create a buffer for performing parallel reduction using the given binary
118 * operation. The results of the reduction are placed into this buffer.
119 * @exception ClassCastException (unchecked exception) Thrown if this
120 * buffer's element data type and the given binary operation's argument data
121 * type are not the same.
122 */
123 public Buf getReductionBuf(Op op) {
124 return new Unsigned16BitIntegerItemReductionBuf(this, (IntegerOp) op);
125 }
126
127 // Hidden operations.
128 /**
129 * {@inheritDoc}
130 *
131 * Send as many items as possible from this buffer to the given byte buffer.
132 * <P>
133 * The <code>sendItems()</code> method must not block the calling thread; if it
134 * does, all message I/O in MP will be blocked.
135 */
136 protected int sendItems(int i,
137 ByteBuffer buffer) {
138 if (buffer.remaining() >= 2) {
139 buffer.putShort((short) this.item);
140 return 1;
141 } else {
142 return 0;
143 }
144 }
145
146 /**
147 * {@inheritDoc}
148 *
149 * Receive as many items as possible from the given byte buffer to this
150 * buffer.
151 * <P>
152 * The <code>receiveItems()</code> method must not block the calling thread; if
153 * it does, all message I/O in MP will be blocked.
154 */
155 protected int receiveItems(int i,
156 int num,
157 ByteBuffer buffer) {
158 if (num >= 1 && buffer.remaining() >= 2) {
159 this.item = buffer.getShort() & 0xFFFF;
160 return 1;
161 } else {
162 return 0;
163 }
164 }
165
166 }