Iterate on nodes instead of single bits to save node resolution for each
single bit.
Signed-off-by: Christian Göttsche <cgzones@xxxxxxxxxxxxxx>
---
v2:
use braces for all if-else branches when used for at least one of them
---
libsepol/src/ebitmap.c | 41 +++++++++++++++++++++++++++++++++++------
1 file changed, 35 insertions(+), 6 deletions(-)
diff --git a/libsepol/src/ebitmap.c b/libsepol/src/ebitmap.c
index c9164c5e..6dbbddfd 100644
--- a/libsepol/src/ebitmap.c
+++ b/libsepol/src/ebitmap.c
@@ -74,15 +74,44 @@ int ebitmap_union(ebitmap_t * dst, const ebitmap_t * e1)
int ebitmap_and(ebitmap_t *dst, const ebitmap_t *e1, const ebitmap_t *e2)
{
- unsigned int i, length = min(ebitmap_length(e1), ebitmap_length(e2));
+ const ebitmap_node_t *n1, *n2;
+ ebitmap_node_t *new, *prev = NULL;
+
ebitmap_init(dst);
- for (i=0; i < length; i++) {
- if (ebitmap_get_bit(e1, i) && ebitmap_get_bit(e2, i)) {
- int rc = ebitmap_set_bit(dst, i, 1);
- if (rc < 0)
- return rc;
+
+ n1 = e1->node;
+ n2 = e2->node;
+ while (n1 && n2) {
+ if (n1->startbit == n2->startbit) {
+ if (n1->map & n2->map) {
+ new = malloc(sizeof(ebitmap_node_t));
+ if (!new) {
+ ebitmap_destroy(dst);
+ return -ENOMEM;
+ }
+ new->startbit = n1->startbit;
+ new->map = n1->map & n2->map;
+ new->next = NULL;
+
+ if (prev)
+ prev->next = new;
+ else
+ dst->node = new;
+ prev = new;
+ }
+
+ n1 = n1->next;
+ n2 = n2->next;
+ } else if (n1->startbit > n2->startbit) {
+ n2 = n2->next;
+ } else {
+ n1 = n1->next;
}
}
+
+ if (prev)
+ dst->highbit = prev->startbit + MAPSIZE;
+
return 0;
}
--
2.36.1
