1 //******************************************************************************
2 //
3 // File: DoubleArrayBuf_1.java
4 // Package: edu.rit.mp.buf
5 // Unit: Class edu.rit.mp.buf.DoubleArrayBuf_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 import java.nio.DoubleBuffer;
44
45 import edu.rit.mp.Buf;
46 import edu.rit.pj.reduction.DoubleOp;
47 import edu.rit.pj.reduction.Op;
48 import edu.rit.util.Range;
49
50 /**
51 * Class DoubleArrayBuf_1 provides a buffer for an array of double items sent or
52 * received using the Message Protocol (MP). The array element stride must be 1.
53 * While an instance of class DoubleArrayBuf may be constructed directly,
54 * normally you will use a factory method in class {@linkplain
55 * edu.rit.mp.DoubleBuf DoubleBuf}. See that class for further information.
56 *
57 * @author Alan Kaminsky
58 * @version 25-Oct-2007
59 */
60 public class DoubleArrayBuf_1
61 extends DoubleArrayBuf {
62
63 // Exported constructors.
64 /**
65 * Construct a new double array buffer.
66 *
67 * @param theArray Array.
68 * @param theRange Range of array elements to include in the buffer. The
69 * stride is assumed to be 1.
70 */
71 public DoubleArrayBuf_1(double[] theArray,
72 Range theRange) {
73 super(theArray, theRange);
74 }
75
76 // Exported operations.
77 /**
78 * {@inheritDoc}
79 *
80 * Obtain the given item from this buffer.
81 * <P>
82 * The <code>get()</code> method must not block the calling thread; if it does,
83 * all message I/O in MP will be blocked.
84 */
85 public double get(int i) {
86 return myArray[myArrayOffset + i];
87 }
88
89 /**
90 * {@inheritDoc}
91 *
92 * Store the given item in this buffer.
93 * <P>
94 * The <code>put()</code> method must not block the calling thread; if it does,
95 * all message I/O in MP will be blocked.
96 */
97 public void put(int i,
98 double item) {
99 myArray[myArrayOffset + i] = item;
100 }
101
102 /**
103 * {@inheritDoc}
104 *
105 * Create a buffer for performing parallel reduction using the given binary
106 * operation. The results of the reduction are placed into this buffer.
107 * @exception ClassCastException (unchecked exception) Thrown if this
108 * buffer's element data type and the given binary operation's argument data
109 * type are not the same.
110 */
111 public Buf getReductionBuf(Op op) {
112 return new DoubleArrayReductionBuf_1(myArray, myRange, (DoubleOp) op);
113 }
114
115 // Hidden operations.
116 /**
117 * {@inheritDoc}
118 *
119 * Send as many items as possible from this buffer to the given byte buffer.
120 * <P>
121 * The <code>sendItems()</code> method must not block the calling thread; if it
122 * does, all message I/O in MP will be blocked.
123 */
124 protected int sendItems(int i,
125 ByteBuffer buffer) {
126 DoubleBuffer doublebuffer = buffer.asDoubleBuffer();
127 int n = Math.min(myLength - i, doublebuffer.remaining());
128 doublebuffer.put(myArray, myArrayOffset + i, n);
129 buffer.position(buffer.position() + 8 * n);
130 return n;
131 }
132
133 /**
134 * {@inheritDoc}
135 *
136 * Receive as many items as possible from the given byte buffer to this
137 * buffer.
138 * <P>
139 * The <code>receiveItems()</code> method must not block the calling thread; if
140 * it does, all message I/O in MP will be blocked.
141 */
142 protected int receiveItems(int i,
143 int num,
144 ByteBuffer buffer) {
145 DoubleBuffer doublebuffer = buffer.asDoubleBuffer();
146 int n = Math.min(num, Math.min(myLength - i, doublebuffer.remaining()));
147 doublebuffer.get(myArray, myArrayOffset + i, n);
148 buffer.position(buffer.position() + 8 * n);
149 return n;
150 }
151
152 }