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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  import org.apache.http.annotation.NotThreadSafe;
31  
32  /**
33   * This class represents a context of a parsing operation:
34   * <ul>
35   *  <li>the current position the parsing operation is expected to start at</li>
36   *  <li>the bounds limiting the scope of the parsing operation</li>
37   * </ul>
38   *
39   * @since 4.0
40   */
41  @NotThreadSafe
42  public class ParserCursor {
43  
44      private final int lowerBound;
45      private final int upperBound;
46      private int pos;
47  
48      public ParserCursor(final int lowerBound, final int upperBound) {
49          super();
50          if (lowerBound < 0) {
51              throw new IndexOutOfBoundsException("Lower bound cannot be negative");
52          }
53          if (lowerBound > upperBound) {
54              throw new IndexOutOfBoundsException("Lower bound cannot be greater then upper bound");
55          }
56          this.lowerBound = lowerBound;
57          this.upperBound = upperBound;
58          this.pos = lowerBound;
59      }
60  
61      public int getLowerBound() {
62          return this.lowerBound;
63      }
64  
65      public int getUpperBound() {
66          return this.upperBound;
67      }
68  
69      public int getPos() {
70          return this.pos;
71      }
72  
73      public void updatePos(final int pos) {
74          if (pos < this.lowerBound) {
75              throw new IndexOutOfBoundsException("pos: "+pos+" < lowerBound: "+this.lowerBound);
76          }
77          if (pos > this.upperBound) {
78              throw new IndexOutOfBoundsException("pos: "+pos+" > upperBound: "+this.upperBound);
79          }
80          this.pos = pos;
81      }
82  
83      public boolean atEnd() {
84          return this.pos >= this.upperBound;
85      }
86  
87      @Override
88      public String toString() {
89          final StringBuilder buffer = new StringBuilder();
90          buffer.append('[');
91          buffer.append(Integer.toString(this.lowerBound));
92          buffer.append('>');
93          buffer.append(Integer.toString(this.pos));
94          buffer.append('>');
95          buffer.append(Integer.toString(this.upperBound));
96          buffer.append(']');
97          return buffer.toString();
98      }
99  
100 }