BitSet.java revision 953:221a84ef44c0 
1/*
2 * Permission is hereby granted, free of charge, to any person obtaining a copy of
3 * this software and associated documentation files (the "Software"), to deal in
4 * the Software without restriction, including without limitation the rights to
5 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
6 * of the Software, and to permit persons to whom the Software is furnished to do
7 * so, subject to the following conditions:
8 *
9 * The above copyright notice and this permission notice shall be included in all
10 * copies or substantial portions of the Software.
11 *
12 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
13 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
14 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
15 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
16 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
17 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
18 * SOFTWARE.
19 */
20package jdk.nashorn.internal.runtime.regexp.joni;
21
22public final class BitSet {
23    static final int BITS_PER_BYTE = 8;
24    public static final int SINGLE_BYTE_SIZE = (1 << BITS_PER_BYTE);
25    private static final int BITS_IN_ROOM = 4 * BITS_PER_BYTE;
26    static final int BITSET_SIZE = (SINGLE_BYTE_SIZE / BITS_IN_ROOM);
27    static final int ROOM_SHIFT = log2(BITS_IN_ROOM);
28
29    final int[] bits = new int[BITSET_SIZE];
30
31    private static final int BITS_TO_STRING_WRAP = 4;
32    @Override
33    public String toString() {
34        final StringBuilder buffer = new StringBuilder();
35        buffer.append("BitSet");
36        for (int i=0; i<SINGLE_BYTE_SIZE; i++) {
37            if ((i % (SINGLE_BYTE_SIZE / BITS_TO_STRING_WRAP)) == 0) buffer.append("\n  ");
38            buffer.append(at(i) ? "1" : "0");
39        }
40        return buffer.toString();
41    }
42
43    public boolean at(final int pos) {
44        return (bits[pos >>> ROOM_SHIFT] & bit(pos)) != 0;
45    }
46
47    public void set(final int pos) {
48        bits[pos >>> ROOM_SHIFT] |= bit(pos);
49    }
50
51    public void clear(final int pos) {
52        bits[pos >>> ROOM_SHIFT] &= ~bit(pos);
53    }
54
55    public void clear() {
56        for (int i=0; i<BITSET_SIZE; i++) bits[i]=0;
57    }
58
59    public boolean isEmpty() {
60        for (int i=0; i<BITSET_SIZE; i++) {
61            if (bits[i] != 0) return false;
62        }
63        return true;
64    }
65
66    public void setRange(final int from, final int to) {
67        for (int i=from; i<=to && i < SINGLE_BYTE_SIZE; i++) set(i);
68    }
69
70    public void invert() {
71        for (int i=0; i<BITSET_SIZE; i++) bits[i] = ~bits[i];
72    }
73
74    public void invertTo(final BitSet to) {
75        for (int i=0; i<BITSET_SIZE; i++) to.bits[i] = ~bits[i];
76    }
77
78    public void and(final BitSet other) {
79        for (int i=0; i<BITSET_SIZE; i++) bits[i] &= other.bits[i];
80    }
81
82    public void or(final BitSet other) {
83        for (int i=0; i<BITSET_SIZE; i++) bits[i] |= other.bits[i];
84    }
85
86    public void copy(final BitSet other) {
87        for (int i=0; i<BITSET_SIZE; i++) bits[i] = other.bits[i];
88    }
89
90    public int numOn() {
91        int num = 0;
92        for (int i=0; i<SINGLE_BYTE_SIZE; i++) {
93            if (at(i)) num++;
94        }
95        return num;
96    }
97
98    static int bit(final int pos){
99        return 1 << (pos % SINGLE_BYTE_SIZE);
100    }
101
102    private static int log2(int n){
103        int log = 0;
104        while ((n >>>= 1) != 0) log++;
105        return log;
106    }
107
108}
109