|
1
20
21 package JFlex;
22
23
24
29 public final class CharSet {
30
31 final static int BITS = 6; final static int MOD = (1<<BITS)-1;
34 long bits[];
35
36 private int numElements;
37
38
39 public CharSet() {
40 bits = new long[1];
41 }
42
43
44 public CharSet(int initialSize, int character) {
45 bits = new long[(initialSize >> BITS)+1];
46 add(character);
47 }
48
49
50 public void add(int character) {
51 resize(character);
52
53 if ( (bits[character >> BITS] & (1L << (character & MOD))) == 0) numElements++;
54
55 bits[character >> BITS] |= (1L << (character & MOD));
56 }
57
58
59 private int nbits2size (int nbits) {
60 return ((nbits >> BITS) + 1);
61 }
62
63
64 private void resize(int nbits) {
65 int needed = nbits2size(nbits);
66
67 if (needed < bits.length) return;
68
69 long newbits[] = new long[Math.max(bits.length*2,needed)];
70 System.arraycopy(bits, 0, newbits, 0, bits.length);
71
72 bits = newbits;
73 }
74
75
76 public boolean isElement(int character) {
77 int index = character >> BITS;
78 if (index >= bits.length) return false;
79 return (bits[index] & (1L << (character & MOD))) != 0;
80 }
81
82
83 public CharSetEnumerator characters() {
84 return new CharSetEnumerator(this);
85 }
86
87
88 public boolean containsElements() {
89 return numElements > 0;
90 }
91
92 public int size() {
93 return numElements;
94 }
95
96 public String  toString() {
97 CharSetEnumerator set = characters();
98
99 StringBuffer result = new StringBuffer ("{");
100
101 if ( set.hasMoreElements() ) result.append(""+set.nextElement());
102
103 while ( set.hasMoreElements() ) {
104 int i = set.nextElement();
105 result.append( ", "+(int)i);
106 }
107
108 result.append("}");
109
110 return result.toString();
111 }
112 }
113 |
Popular Tags |
Java API By Example, From Geeks To Geeks.