1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
|
/**
* Copyright 2015 JogAmp Community. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification, are
* permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this list of
* conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice, this list
* of conditions and the following disclaimer in the documentation and/or other materials
* provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY JogAmp Community ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JogAmp Community OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* The views and conclusions contained in the software and documentation are those of the
* authors and should not be interpreted as representing official policies, either expressed
* or implied, of JogAmp Community.
*/
package com.jogamp.common.util;
/**
* Simple bitfield interface for efficient bit storage access in O(1).
* @since 2.3.2
*/
public interface Bitfield {
/**
* Bit operation utilities (static).
*/
public static class Util {
/**
* Returns the number of set bits within given 32bit integer in O(1)
* using <i>HAKEM Bit Count</i>:
* <pre>
* http://www.inwap.com/pdp10/hbaker/hakmem/hakmem.html
* http://home.pipeline.com/~hbaker1/hakmem/hacks.html#item169
* http://tekpool.wordpress.com/category/bit-count/
* </pre>
*/
public static final int getBitCount(final int n) {
// Note: Original used 'unsigned int',
// hence we use the unsigned right-shift '>>>'
int c = n;
c -= (n >>> 1) & 033333333333;
c -= (n >>> 2) & 011111111111;
return ( (c + ( c >>> 3 ) ) & 030707070707 ) % 63;
}
}
/**
* Simple {@link Bitfield} factory for returning the efficient implementation.
*/
public static class Factory {
/**
* Creates am efficient {@link Bitfield} instance based on the requested {@code storageBitSize}.
* <p>
* Implementation returns a plain 32 bit integer field implementation for
* {@code storageBitSize} ≤ 32 bits or an 32 bit integer array implementation otherwise.
* </p>
*/
public static Bitfield create(final int storageBitSize) {
if( 32 >= storageBitSize ) {
return new jogamp.common.util.Int32Bitfield();
} else {
return new jogamp.common.util.Int32ArrayBitfield(storageBitSize);
}
}
}
/**
* Returns the storage size in bit units, e.g. 32 bit for implementations using one {@code int} field.
*/
int getStorageBitSize();
/**
* Returns the 32 bit integer mask w/ its lowest bit at the bit number {@code rightBitnum}.
* @param rightBitnum bit number denoting the position of the lowest bit, restricted to [0..{@link #getStorageBitSize()}-32].
* @throws IndexOutOfBoundsException if {@code rightBitnum} is out of bounds
*/
int getInt32(final int rightBitnum) throws IndexOutOfBoundsException;
/**
* Sets the given 32 bit integer mask w/ its lowest bit at the bit number {@code rightBitnum}.
* @param rightBitnum bit number denoting the position of the lowest bit, restricted to [0..{@link #getStorageBitSize()}-32].
* @param mask denoting the 32 bit mask value to store
* @throws IndexOutOfBoundsException if {@code rightBitnum} is out of bounds
*/
void putInt32(final int rightBitnum, final int mask) throws IndexOutOfBoundsException;
/**
* Return <code>true</code> if the bit at position <code>bitnum</code> is set, otherwise <code>false</code>.
* @param bitnum bit number, restricted to [0..{@link #getStorageBitSize()}-1].
* @throws IndexOutOfBoundsException if {@code bitnum} is out of bounds
*/
boolean get(final int bitnum) throws IndexOutOfBoundsException;
/**
* Set or clear the bit at position <code>bitnum</code> according to <code>bit</code>
* and return the previous value.
* @param bitnum bit number, restricted to [0..{@link #getStorageBitSize()}-1].
* @throws IndexOutOfBoundsException if {@code bitnum} is out of bounds
*/
boolean put(final int bitnum, final boolean bit) throws IndexOutOfBoundsException;
/**
* Set the bit at position <code>bitnum</code> according to <code>bit</code>.
* @param bitnum bit number, restricted to [0..{@link #getStorageBitSize()}-1].
* @throws IndexOutOfBoundsException if {@code bitnum} is out of bounds
*/
void set(final int bitnum) throws IndexOutOfBoundsException;
/**
* Clear the bit at position <code>bitnum</code> according to <code>bit</code>.
* @param bitnum bit number, restricted to [0..{@link #getStorageBitSize()}-1].
* @throws IndexOutOfBoundsException if {@code bitnum} is out of bounds
*/
void clear(final int bitnum) throws IndexOutOfBoundsException;
/**
* Returns the number of set bits within this bitfield.
* <p>
* Utilizes {#link {@link Bitfield.Util#getBitCount(int)}}.
* </p>
*/
int getBitCount();
}
|
