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git.ipfire.org Git - thirdparty/systemd.git/blob - src/basic/bitmap.c
1 /* SPDX-License-Identifier: LGPL-2.1+ */
9 #include "alloc-util.h"
17 size_t bitmaps_allocated
;
20 /* Bitmaps are only meant to store relatively small numbers
21 * (corresponding to, say, an enum), so it is ok to limit
22 * the max entry. 64k should be plenty. */
23 #define BITMAPS_MAX_ENTRY 0xffff
25 /* This indicates that we reached the end of the bitmap */
26 #define BITMAP_END ((unsigned) -1)
28 #define BITMAP_NUM_TO_OFFSET(n) ((n) / (sizeof(uint64_t) * 8))
29 #define BITMAP_NUM_TO_REM(n) ((n) % (sizeof(uint64_t) * 8))
30 #define BITMAP_OFFSET_TO_NUM(offset, rem) ((offset) * sizeof(uint64_t) * 8 + (rem))
32 Bitmap
*bitmap_new(void) {
33 return new0(Bitmap
, 1);
36 Bitmap
*bitmap_copy(Bitmap
*b
) {
43 ret
->bitmaps
= newdup(uint64_t, b
->bitmaps
, b
->n_bitmaps
);
47 ret
->n_bitmaps
= ret
->bitmaps_allocated
= b
->n_bitmaps
;
51 void bitmap_free(Bitmap
*b
) {
59 int bitmap_ensure_allocated(Bitmap
**b
) {
76 int bitmap_set(Bitmap
*b
, unsigned n
) {
82 /* we refuse to allocate huge bitmaps */
83 if (n
> BITMAPS_MAX_ENTRY
)
86 offset
= BITMAP_NUM_TO_OFFSET(n
);
88 if (offset
>= b
->n_bitmaps
) {
89 if (!GREEDY_REALLOC0(b
->bitmaps
, b
->bitmaps_allocated
, offset
+ 1))
92 b
->n_bitmaps
= offset
+ 1;
95 bitmask
= UINT64_C(1) << BITMAP_NUM_TO_REM(n
);
97 b
->bitmaps
[offset
] |= bitmask
;
102 void bitmap_unset(Bitmap
*b
, unsigned n
) {
109 offset
= BITMAP_NUM_TO_OFFSET(n
);
111 if (offset
>= b
->n_bitmaps
)
114 bitmask
= UINT64_C(1) << BITMAP_NUM_TO_REM(n
);
116 b
->bitmaps
[offset
] &= ~bitmask
;
119 bool bitmap_isset(Bitmap
*b
, unsigned n
) {
126 offset
= BITMAP_NUM_TO_OFFSET(n
);
128 if (offset
>= b
->n_bitmaps
)
131 bitmask
= UINT64_C(1) << BITMAP_NUM_TO_REM(n
);
133 return !!(b
->bitmaps
[offset
] & bitmask
);
136 bool bitmap_isclear(Bitmap
*b
) {
142 for (i
= 0; i
< b
->n_bitmaps
; i
++)
143 if (b
->bitmaps
[i
] != 0)
149 void bitmap_clear(Bitmap
*b
) {
154 b
->bitmaps
= mfree(b
->bitmaps
);
156 b
->bitmaps_allocated
= 0;
159 bool bitmap_iterate(Bitmap
*b
, Iterator
*i
, unsigned *n
) {
161 unsigned offset
, rem
;
166 if (!b
|| i
->idx
== BITMAP_END
)
169 offset
= BITMAP_NUM_TO_OFFSET(i
->idx
);
170 rem
= BITMAP_NUM_TO_REM(i
->idx
);
171 bitmask
= UINT64_C(1) << rem
;
173 for (; offset
< b
->n_bitmaps
; offset
++) {
174 if (b
->bitmaps
[offset
]) {
175 for (; bitmask
; bitmask
<<= 1, rem
++) {
176 if (b
->bitmaps
[offset
] & bitmask
) {
177 *n
= BITMAP_OFFSET_TO_NUM(offset
, rem
);
194 bool bitmap_equal(Bitmap
*a
, Bitmap
*b
) {
195 size_t common_n_bitmaps
;
208 common_n_bitmaps
= MIN(a
->n_bitmaps
, b
->n_bitmaps
);
209 if (memcmp_safe(a
->bitmaps
, b
->bitmaps
, sizeof(uint64_t) * common_n_bitmaps
) != 0)
212 c
= a
->n_bitmaps
> b
->n_bitmaps
? a
: b
;
213 for (i
= common_n_bitmaps
; i
< c
->n_bitmaps
; i
++)
214 if (c
->bitmaps
[i
] != 0)