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Commit | Line | Data |
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064af421 | 1 | /* |
e0edde6f | 2 | * Copyright (c) 2008, 2009, 2011 Nicira, Inc. |
064af421 | 3 | * |
a14bc59f BP |
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: | |
064af421 | 7 | * |
a14bc59f BP |
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. | |
064af421 BP |
15 | */ |
16 | ||
17 | #include <config.h> | |
18 | #include "bitmap.h" | |
19 | #include <string.h> | |
20 | ||
77d895d6 BP |
21 | /* Allocates and returns a bitmap initialized to all-1-bits. */ |
22 | unsigned long * | |
23 | bitmap_allocate1(size_t n_bits) | |
24 | { | |
25 | size_t n_bytes = bitmap_n_bytes(n_bits); | |
26 | size_t n_longs = bitmap_n_longs(n_bits); | |
27 | unsigned long *bitmap; | |
28 | ||
29 | /* Allocate and initialize most of the bitmap. */ | |
30 | bitmap = xmalloc(n_bytes); | |
31 | memset(bitmap, 0xff, n_bytes); | |
32 | ||
33 | /* Ensure that the last "unsigned long" in the bitmap only has as many | |
34 | * 1-bits as there actually should be. */ | |
35 | bitmap[n_longs - 1] = (1UL << (n_bits % BITMAP_ULONG_BITS)) - 1; | |
36 | ||
37 | return bitmap; | |
38 | } | |
39 | ||
064af421 BP |
40 | /* Sets 'count' consecutive bits in 'bitmap', starting at bit offset 'start', |
41 | * to 'value'. */ | |
42 | void | |
43 | bitmap_set_multiple(unsigned long *bitmap, size_t start, size_t count, | |
44 | bool value) | |
45 | { | |
46 | for (; count && start % BITMAP_ULONG_BITS; count--) { | |
47 | bitmap_set(bitmap, start++, value); | |
48 | } | |
49 | for (; count >= BITMAP_ULONG_BITS; count -= BITMAP_ULONG_BITS) { | |
50 | *bitmap_unit__(bitmap, start) = -(unsigned long) value; | |
51 | start += BITMAP_ULONG_BITS; | |
52 | } | |
53 | for (; count; count--) { | |
54 | bitmap_set(bitmap, start++, value); | |
55 | } | |
56 | } | |
57 | ||
58 | /* Compares the 'n' bits in bitmaps 'a' and 'b'. Returns true if all bits are | |
59 | * equal, false otherwise. */ | |
60 | bool | |
61 | bitmap_equal(const unsigned long *a, const unsigned long *b, size_t n) | |
62 | { | |
63 | size_t i; | |
64 | ||
65 | if (memcmp(a, b, n / BITMAP_ULONG_BITS * sizeof(unsigned long))) { | |
66 | return false; | |
67 | } | |
68 | for (i = ROUND_DOWN(n, BITMAP_ULONG_BITS); i < n; i++) { | |
69 | if (bitmap_is_set(a, i) != bitmap_is_set(b, i)) { | |
70 | return false; | |
71 | } | |
72 | } | |
73 | return true; | |
74 | } | |
7cc48aed BP |
75 | |
76 | /* Scans 'bitmap' from bit offset 'start' to 'end', excluding 'end' itself. | |
77 | * Returns the bit offset of the lowest-numbered bit set to 1, or 'end' if | |
78 | * all of the bits are set to 0. */ | |
79 | size_t | |
80 | bitmap_scan(const unsigned long int *bitmap, size_t start, size_t end) | |
81 | { | |
82 | /* XXX slow */ | |
83 | size_t i; | |
84 | ||
85 | for (i = start; i < end; i++) { | |
86 | if (bitmap_is_set(bitmap, i)) { | |
87 | break; | |
88 | } | |
89 | } | |
90 | return i; | |
91 | } |