1 //****************************************************************************** 2 // 3 // File: SharedSigned16BitIntegerReductionBuf.java 4 // Package: edu.rit.mp.buf 5 // Unit: Class edu.rit.mp.buf.SharedSigned16BitIntegerReductionBuf 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.IntegerOp; 46 import edu.rit.pj.reduction.Op; 47 import edu.rit.pj.reduction.SharedInteger; 48 49 /** 50 * Class SharedSigned16BitIntegerReductionBuf provides a reduction buffer for 51 * class {@linkplain SharedSigned16BitIntegerBuf}. 52 * 53 * @author Alan Kaminsky 54 * @version 26-Oct-2007 55 */ 56 class SharedSigned16BitIntegerReductionBuf 57 extends SharedSigned16BitIntegerBuf { 58 59 // Hidden data members. 60 IntegerOp myOp; 61 62 // Exported constructors. 63 /** 64 * Construct a new shared signed 16-bit integer reduction buffer. 65 * 66 * @param item SharedInteger object that wraps the item. 67 * @param op Binary operation. 68 * @exception NullPointerException (unchecked exception) Thrown if 69 * <code>op</code> is null. 70 */ 71 public SharedSigned16BitIntegerReductionBuf(SharedInteger item, 72 IntegerOp op) { 73 super(item); 74 myOp = op; 75 } 76 77 // Exported operations. 78 /** 79 * {@inheritDoc} 80 * 81 * Store the given item in this buffer. 82 * <P> 83 * The <code>put()</code> method must not block the calling thread; if it does, 84 * all message I/O in MP will be blocked. 85 */ 86 public void put(int i, 87 int item) { 88 myItem.reduce(item, myOp); 89 } 90 91 /** 92 * {@inheritDoc} 93 * 94 * Create a buffer for performing parallel reduction using the given binary 95 * operation. The results of the reduction are placed into this buffer. 96 * @exception ClassCastException (unchecked exception) Thrown if this 97 * buffer's element data type and the given binary operation's argument data 98 * type are not the same. 99 */ 100 public Buf getReductionBuf(Op op) { 101 throw new UnsupportedOperationException(); 102 } 103 104 // Hidden operations. 105 /** 106 * {@inheritDoc} 107 * 108 * Receive as many items as possible from the given byte buffer to this 109 * buffer. 110 * <P> 111 * The <code>receiveItems()</code> method must not block the calling thread; if 112 * it does, all message I/O in MP will be blocked. 113 */ 114 protected int receiveItems(int i, 115 int num, 116 ByteBuffer buffer) { 117 if (num >= 1 && buffer.remaining() >= 2) { 118 myItem.reduce(buffer.getShort(), myOp); 119 return 1; 120 } else { 121 return 0; 122 } 123 } 124 125 }