2 * Copyright (c) 2008, 2009, 2011, 2014 Nicira, Inc.
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:
8 * http://www.apache.org/licenses/LICENSE-2.0
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.
22 /* Allocates and returns a bitmap initialized to all-1-bits. */
24 bitmap_allocate1(size_t n_bits)
26 size_t n_bytes = bitmap_n_bytes(n_bits);
27 size_t n_longs = bitmap_n_longs(n_bits);
28 size_t r_bits = n_bits % BITMAP_ULONG_BITS;
29 unsigned long *bitmap;
31 /* Allocate and initialize most of the bitmap. */
32 bitmap = xmalloc(n_bytes);
33 memset(bitmap, 0xff, n_bytes);
35 /* Ensure that the last "unsigned long" in the bitmap only has as many
36 * 1-bits as there actually should be. */
38 bitmap[n_longs - 1] = (1UL << r_bits) - 1;
44 /* Sets 'count' consecutive bits in 'bitmap', starting at bit offset 'start',
47 bitmap_set_multiple(unsigned long *bitmap, size_t start, size_t count,
50 for (; count && start % BITMAP_ULONG_BITS; count--) {
51 bitmap_set(bitmap, start++, value);
53 for (; count >= BITMAP_ULONG_BITS; count -= BITMAP_ULONG_BITS) {
54 *bitmap_unit__(bitmap, start) = -(unsigned long) value;
55 start += BITMAP_ULONG_BITS;
57 for (; count; count--) {
58 bitmap_set(bitmap, start++, value);
62 /* Compares the 'n' bits in bitmaps 'a' and 'b'. Returns true if all bits are
63 * equal, false otherwise. */
65 bitmap_equal(const unsigned long *a, const unsigned long *b, size_t n)
69 if (memcmp(a, b, n / BITMAP_ULONG_BITS * sizeof(unsigned long))) {
72 for (i = ROUND_DOWN(n, BITMAP_ULONG_BITS); i < n; i++) {
73 if (bitmap_is_set(a, i) != bitmap_is_set(b, i)) {
80 /* Scans 'bitmap' from bit offset 'start' to 'end', excluding 'end' itself.
81 * Returns the bit offset of the lowest-numbered bit set to 'target', or 'end'
82 * if all of the bits are set to '!target'. */
84 bitmap_scan(const unsigned long int *bitmap, bool target,
85 size_t start, size_t end)
90 for (i = start; i < end; i++) {
91 if (bitmap_is_set(bitmap, i) == target) {
98 /* Returns the number of 1-bits in the 'n'-bit bitmap at 'bitmap'. */
100 bitmap_count1(const unsigned long int *bitmap, size_t n)
105 BUILD_ASSERT(ULONG_MAX <= UINT64_MAX);
106 for (i = 0; i < BITMAP_N_LONGS(n); i++) {
107 count += count_1bits(bitmap[i]);
113 /* "dst &= arg;" for n-bit dst and arg. */
115 bitmap_and(unsigned long *dst, const unsigned long *arg, size_t n)
119 for (i = 0; i < BITMAP_N_LONGS(n); i++) {
124 /* "dst |= arg;" for n-bit dst and arg. */
126 bitmap_or(unsigned long *dst, const unsigned long *arg, size_t n)
130 for (i = 0; i < BITMAP_N_LONGS(n); i++) {
135 /* "dst = ~dst;" for n-bit dst. */
137 bitmap_not(unsigned long *dst, size_t n)
141 for (i = 0; i < n / BITMAP_ULONG_BITS; i++) {
144 if (n % BITMAP_ULONG_BITS) {
145 dst[i] ^= (1u << (n % BITMAP_ULONG_BITS)) - 1;
149 /* Returns true if all of the 'n' bits in 'bitmap' are 0,
150 * false if at least one bit is a 1.*/
152 bitmap_is_all_zeros(const unsigned long *bitmap, size_t n)
154 return bitmap_scan(bitmap, true, 0, n) == n;