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 /**
33 * Create a circular buffer of a given capacity allowing to compute efficiently
34 * the mean of the values storied.
35 *
36 * @author leberre
37 *
38 */
39 public class CircularBuffer {
40
41 private final int[] values;
42 private int index = 0;
43 private long sum = 0;
44 private boolean full = false;
45
46 public CircularBuffer(int capacity) {
47 this.values = new int[capacity];
48 }
49
50 public void push(int value) {
51 if (!this.full) {
52 this.values[this.index++] = value;
53 this.sum += value;
54 if (this.index == this.values.length) {
55 this.full = true;
56 this.index = -1;
57 }
58 return;
59 }
60 this.index++;
61 if (this.index == this.values.length) {
62 this.index = 0;
63 }
64 // buffer full, overwrite
65 this.sum -= this.values[this.index];
66 this.values[this.index] = value;
67 this.sum += value;
68 }
69
70 public long average() {
71 if (this.full) {
72 return this.sum / this.values.length;
73 }
74 if (this.index == 0) {
75 return 0;
76 }
77 return this.sum / this.index;
78 }
79
80 public void clear() {
81 this.index = 0;
82 this.full = false;
83 this.sum = 0;
84 }
85
86 public boolean isFull() {
87 return this.full;
88 }
89 }