src/web/org/codehaus/groovy/grails/web/pages/Reverse.java

   1 /*
   2  * Copyright 2004-2005 the original author or authors.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *      http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16 package org.codehaus.groovy.grails.web.pages;
  17 /**
  18  * NOTE: Based on work done by on the GSP standalone project (https://gsp.dev.java.net/)
  19  *
  20  * Utility class to reverse a char sequence.
  21  *
  22  * @author Troy Heninger
  23  * Date: Jan 10, 2004
  24  *
  25  */
  26 class Reverse implements CharSequence {
  27         private CharSequence text;
  28         private int start, end, anchor;
  29
  30         Reverse(CharSequence text) {
  31                 this(text, 0, text.length());
  32         }
  33
  34         Reverse(CharSequence text, int start, int end) {
  35                 this.text = text;
  36                 this.start = start;
  37                 this.end = end;
  38                 anchor = end - 1;
  39         }
  40         public char charAt(int index) {
  41                 return text.charAt(anchor - index);
  42         }
  43
  44         public int length() {
  45                 return end - start;
  46         }
  47
  48         public CharSequence subSequence(int start, int end) {
  49                 return new Reverse(text, anchor - end, anchor - start);
  50         }
  51
  52         public String toString() {
  53                 int len = length();
  54                 StringBuffer buf = new StringBuffer(len);
  55                 for (int ix = anchor; ix >= start; ix--) {
  56                         buf.append(text.charAt(ix));
  57                 }
  58                 return buf.toString();
  59         }
  60 } // Reverse