1 /*******************************************************************************
2 * SAT4J: a SATisfiability library for Java Copyright (C) 2004, 2012 Artois University and CNRS
3 *
4 * All rights reserved. This program and the accompanying materials
5 * are made available under the terms of the Eclipse Public License v1.0
6 * which accompanies this distribution, and is available at
7 * http://www.eclipse.org/legal/epl-v10.html
8 *
9 * Alternatively, the contents of this file may be used under the terms of
10 * either the GNU Lesser General Public License Version 2.1 or later (the
11 * "LGPL"), in which case the provisions of the LGPL are applicable instead
12 * of those above. If you wish to allow use of your version of this file only
13 * under the terms of the LGPL, and not to allow others to use your version of
14 * this file under the terms of the EPL, indicate your decision by deleting
15 * the provisions above and replace them with the notice and other provisions
16 * required by the LGPL. If you do not delete the provisions above, a recipient
17 * may use your version of this file under the terms of the EPL or the LGPL.
18 *
19 * Based on the original MiniSat specification from:
20 *
21 * An extensible SAT solver. Niklas Een and Niklas Sorensson. Proceedings of the
22 * Sixth International Conference on Theory and Applications of Satisfiability
23 * Testing, LNCS 2919, pp 502-518, 2003.
24 *
25 * See www.minisat.se for the original solver in C++.
26 *
27 * Contributors:
28 * CRIL - initial API and implementation
29 *******************************************************************************/
30 package org.sat4j.minisat.core;
31
32 import java.io.Serializable;
33
34 /**
35 * Create a circular buffer of a given capacity allowing to compute efficiently
36 * the mean of the values storied.
37 *
38 * @author leberre
39 *
40 */
41 public class CircularBuffer implements Serializable {
42
43 /**
44 *
45 */
46 private static final long serialVersionUID = 1L;
47 private final int[] values;
48 private int index = 0;
49 private long sum = 0;
50 private boolean full = false;
51
52 public CircularBuffer(int capacity) {
53 this.values = new int[capacity];
54 }
55
56 public void push(int value) {
57 if (!this.full) {
58 this.values[this.index++] = value;
59 this.sum += value;
60 if (this.index == this.values.length) {
61 this.full = true;
62 this.index = -1;
63 }
64 return;
65 }
66 this.index++;
67 if (this.index == this.values.length) {
68 this.index = 0;
69 }
70 // buffer full, overwrite
71 this.sum -= this.values[this.index];
72 this.values[this.index] = value;
73 this.sum += value;
74 }
75
76 public long average() {
77 if (this.full) {
78 return this.sum / this.values.length;
79 }
80 if (this.index == 0) {
81 return 0;
82 }
83 return this.sum / this.index;
84 }
85
86 public void clear() {
87 this.index = 0;
88 this.full = false;
89 this.sum = 0;
90 }
91
92 public boolean isFull() {
93 return this.full;
94 }
95 }