UcharIterator


1   package org.jruby.util.string;
2   
3   /**
4    * UcharIterator - an Iterator on Unicode characters in a UTF-8 byte array.
5    *
6    * <p>A conventional Iterator, remove() is not supported, and there's an extra
7    * nextChar() method that returns a naked int as opposed to a wrapped Integer.
8    * </p>
9    *
10   * @see org.jruby.util.string.Ustr
11   */
12  
13  public class UcharIterator implements java.util.Iterator  , java.io.Serializable   {
14      private static final long serialVersionUID = -2821982911687539515L;
15      private Ustr u;
16      private int next;
17      
18      /**
19       * Creates a new UcharIterator starting at an offset in a buffer.
20       *
21       * @param s the byte array containing UTF-8-encoded Unicode characters.
22       * @param offset how far into the array to start iterating.
23       */
24      public UcharIterator(byte[] s, int offset) {
25          u = new Ustr(s, offset);
26          u.prepareNext();
27          next = u.nextChar();
28      }
29      
30      /**
31       * Tests whether there are any more characters in the buffer.
32       *
33       * @return true or false depending on whether there are more characters.
34       */
35      public boolean hasNext() {
36          return (next != 0);
37      }
38      
39      /**
40       * Retrieve the next Unicode character from a UTF-8 byte buffer, wrapped
41       * in an Integer object. Throws NoSuchElementException if hasNext
42       * would return false.
43       *
44       * @return the next Unicode character as a java.lang.Integer
45       * @throws NoSuchElementException
46       */
47      public Object   next() {
48          if (next == 0)
49              throw new java.util.NoSuchElementException  ("Ran off end of array");
50          Integer   i = new Integer  (next);
51          next = u.nextChar();
52          return i;
53      }
54      
55      /**
56       * Retrieve the next Unicode character from a UTF-8 byte buffer and return
57       * it as an int.  Once the null-termination is hit, returns 0 as many times
58       * as you want to call it.
59       *
60       * @return the next Unicode character as an int, 0 on end-of-string.
61       */
62      public int nextChar() {
63          int i = next;
64          if (i != 0)
65              next = u.nextChar();
66          return i;
67      }
68      
69      /**
70       * Throws an UnsupportedOperationException.
71       *
72       * @throws UnsupportedOperationException
73       */
74      public void remove() {
75          throw new UnsupportedOperationException  ("UcharIterator doesn't remove");
76      }
77      
78  }
79
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