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
|
/* Copyright 2016 IBM Corp.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
* implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "bitmap.h"
static int __bitmap_find_bit(bitmap_t map, unsigned int start, unsigned int count,
bool value)
{
unsigned int el, first_bit;
unsigned int end = start + count;
bitmap_elem_t e, ev;
int b;
ev = value ? -1ul : 0;
el = BITMAP_ELEM(start);
first_bit = BITMAP_BIT(start);
while (start < end) {
e = map[el] ^ ev;
e |= ((1ul << first_bit) - 1);
if (~e)
break;
start = (start + BITMAP_ELSZ) & ~(BITMAP_ELSZ - 1);
first_bit = 0;
el++;
}
for (b = first_bit; b < BITMAP_ELSZ && start < end; b++,start++) {
if ((e & (1ull << b)) == 0)
return start;
}
return -1;
}
int bitmap_find_zero_bit(bitmap_t map, unsigned int start, unsigned int count)
{
return __bitmap_find_bit(map, start, count, false);
}
int bitmap_find_one_bit(bitmap_t map, unsigned int start, unsigned int count)
{
return __bitmap_find_bit(map, start, count, true);
}
|
