1/*
2 * Copyright 2003 The Apache Software Foundation
3 *
4 *  Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 *  Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16package org.mockito.cglib.core;
17
18public class TinyBitSet {
19    private static int[] T = new int[256];
20    private int value = 0;
21
22    private static int gcount(int x) {
23        int c = 0;
24        while (x != 0) {
25            c++;
26            x &= (x - 1);
27        }
28        return c;
29    }
30
31    static {
32        for(int j = 0; j < 256; j++) {
33            T[j] = gcount(j);
34        }
35    }
36
37    private static int topbit(int i) {
38        int j;
39        for (j = 0; i != 0; i ^= j) {
40            j = i & -i;
41        }
42        return j;
43    }
44
45    private static int log2(int i) {
46        int j = 0;
47        for (j = 0; i != 0; i >>= 1) {
48            j++;
49        }
50        return j;
51    }
52
53    public int length() {
54        return log2(topbit(value));
55    }
56
57    public int cardinality() {
58        int w = value;
59        int c = 0;
60        while (w != 0) {
61            c += T[w & 255];
62            w >>= 8;
63        }
64        return c;
65    }
66
67    public boolean get(int index) {
68        return (value & (1 << index)) != 0;
69    }
70
71    public void set(int index) {
72        value |= (1 << index);
73    }
74
75    public void clear(int index) {
76        value &= ~(1 << index);
77    }
78}
79