/**
    * Logback: the reliable, generic, fast and flexible logging framework.
    * Copyright (C) 1999-2015, QOS.ch. All rights reserved.
    *
    * This program and the accompanying materials are dual-licensed under
    * either the terms of the Eclipse Public License v1.0 as published by
    * the Eclipse Foundation
    *
    *   or (per the licensee's choosing)
   *
   * under the terms of the GNU Lesser General Public License version 2.1
   * as published by the Free Software Foundation.
   */
  package ch.qos.logback.core.pattern;
  
  public class SpacePadder {
  
      final static String[] SPACES = { " ", "  ", "    ", "        ", // 1,2,4,8
              // spaces
              "                ", // 16 spaces
              "                                " }; // 32 spaces
  
      final static public void leftPad(StringBuilder buf, String s, int desiredLength) {
          int actualLen = 0;
          if (s != null) {
              actualLen = s.length();
          }
          if (actualLen < desiredLength) {
              spacePad(buf, desiredLength - actualLen);
          }
          if (s != null) {
              buf.append(s);
          }
      }
  
      final static public void rightPad(StringBuilder buf, String s, int desiredLength) {
          int actualLen = 0;
          if (s != null) {
              actualLen = s.length();
          }
          if (s != null) {
              buf.append(s);
          }
          if (actualLen < desiredLength) {
              spacePad(buf, desiredLength - actualLen);
          }
      }
  
      /**
       * Fast space padding method.
       */
      final static public void spacePad(StringBuilder sbuf, int length) {
          while (length >= 32) {
              sbuf.append(SPACES[5]);
              length -= 32;
          }
  
          for (int i = 4; i >= 0; i--) {
              if ((length & (1 << i)) != 0) {
                  sbuf.append(SPACES[i]);
              }
          }
      }
  }