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1   /*
2    * ====================================================================
3    * Licensed to the Apache Software Foundation (ASF) under one
4    * or more contributor license agreements.  See the NOTICE file
5    * distributed with this work for additional information
6    * regarding copyright ownership.  The ASF licenses this file
7    * to you under the Apache License, Version 2.0 (the
8    * "License"); you may not use this file except in compliance
9    * with the License.  You may obtain a copy of the License at
10   *
11   *   http://www.apache.org/licenses/LICENSE-2.0
12   *
13   * Unless required by applicable law or agreed to in writing,
14   * software distributed under the License is distributed on an
15   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
16   * KIND, either express or implied.  See the License for the
17   * specific language governing permissions and limitations
18   * under the License.
19   * ====================================================================
20   *
21   * This software consists of voluntary contributions made by many
22   * individuals on behalf of the Apache Software Foundation.  For more
23   * information on the Apache Software Foundation, please see
24   * <http://www.apache.org/>.
25   *
26   */
27  
28  package org.apache.http.message;
29  
30  /**
31   * This class represents a context of a parsing operation:
32   * <ul>
33   *  <li>the current position the parsing operation is expected to start at</li>
34   *  <li>the bounds limiting the scope of the parsing operation</li>
35   * </ul>
36   *
37   * @since 4.0
38   */
39  public class ParserCursor {
40  
41      private final int lowerBound;
42      private final int upperBound;
43      private int pos;
44  
45      public ParserCursor(final int lowerBound, final int upperBound) {
46          super();
47          if (lowerBound < 0) {
48              throw new IndexOutOfBoundsException("Lower bound cannot be negative");
49          }
50          if (lowerBound > upperBound) {
51              throw new IndexOutOfBoundsException("Lower bound cannot be greater then upper bound");
52          }
53          this.lowerBound = lowerBound;
54          this.upperBound = upperBound;
55          this.pos = lowerBound;
56      }
57  
58      public int getLowerBound() {
59          return this.lowerBound;
60      }
61  
62      public int getUpperBound() {
63          return this.upperBound;
64      }
65  
66      public int getPos() {
67          return this.pos;
68      }
69  
70      public void updatePos(final int pos) {
71          if (pos < this.lowerBound) {
72              throw new IndexOutOfBoundsException("pos: "+pos+" < lowerBound: "+this.lowerBound);
73          }
74          if (pos > this.upperBound) {
75              throw new IndexOutOfBoundsException("pos: "+pos+" > upperBound: "+this.upperBound);
76          }
77          this.pos = pos;
78      }
79  
80      public boolean atEnd() {
81          return this.pos >= this.upperBound;
82      }
83  
84      @Override
85      public String toString() {
86          final StringBuilder buffer = new StringBuilder();
87          buffer.append('[');
88          buffer.append(Integer.toString(this.lowerBound));
89          buffer.append('>');
90          buffer.append(Integer.toString(this.pos));
91          buffer.append('>');
92          buffer.append(Integer.toString(this.upperBound));
93          buffer.append(']');
94          return buffer.toString();
95      }
96  
97  }