001/**
002 * Logback: the reliable, generic, fast and flexible logging framework.
003 * Copyright (C) 1999-2015, QOS.ch. All rights reserved.
004 *
005 * This program and the accompanying materials are dual-licensed under
006 * either the terms of the Eclipse Public License v1.0 as published by
007 * the Eclipse Foundation
008 *
009 *   or (per the licensee's choosing)
010 *
011 * under the terms of the GNU Lesser General Public License version 2.1
012 * as published by the Free Software Foundation.
013 */
014package ch.qos.logback.core.pattern;
015
016public class SpacePadder {
017
018    final static String[] SPACES = { " ", "  ", "    ", "        ", // 1,2,4,8
019            // spaces
020            "                ", // 16 spaces
021            "                                " }; // 32 spaces
022
023    final static public void leftPad(StringBuilder buf, String s, int desiredLength) {
024        int actualLen = 0;
025        if (s != null) {
026            actualLen = s.length();
027        }
028        if (actualLen < desiredLength) {
029            spacePad(buf, desiredLength - actualLen);
030        }
031        if (s != null) {
032            buf.append(s);
033        }
034    }
035
036    final static public void rightPad(StringBuilder buf, String s, int desiredLength) {
037        int actualLen = 0;
038        if (s != null) {
039            actualLen = s.length();
040        }
041        if (s != null) {
042            buf.append(s);
043        }
044        if (actualLen < desiredLength) {
045            spacePad(buf, desiredLength - actualLen);
046        }
047    }
048
049    /**
050     * Fast space padding method.
051     */
052    final static public void spacePad(StringBuilder sbuf, int length) {
053        while (length >= 32) {
054            sbuf.append(SPACES[5]);
055            length -= 32;
056        }
057
058        for (int i = 4; i >= 0; i--) {
059            if ((length & (1 << i)) != 0) {
060                sbuf.append(SPACES[i]);
061            }
062        }
063    }
064}