On Tue, Jul 12, 2022 at 12:09 PM Christian Göttsche
<cgzones@xxxxxxxxxxxxxx> wrote:
>
> Iterate on nodes instead of single bits to save node resolution for each
> single bit.
>
> Signed-off-by: Christian Göttsche <cgzones@xxxxxxxxxxxxxx>
Acked-by: James Carter <jwcart2@xxxxxxxxx>
> ---
> libsepol/src/ebitmap.c | 48 ++++++++++++++++++++++++++++++++++++------
> 1 file changed, 42 insertions(+), 6 deletions(-)
>
> diff --git a/libsepol/src/ebitmap.c b/libsepol/src/ebitmap.c
> index fb20e994..6a63e559 100644
> --- a/libsepol/src/ebitmap.c
> +++ b/libsepol/src/ebitmap.c
> @@ -101,14 +101,50 @@ int ebitmap_xor(ebitmap_t *dst, const ebitmap_t *e1, const ebitmap_t *e2)
>
> int ebitmap_not(ebitmap_t *dst, const ebitmap_t *e1, unsigned int maxbit)
> {
> - unsigned int i;
> + const ebitmap_node_t *n;
> + ebitmap_node_t *new, *prev = NULL;
> + uint32_t startbit, cur_startbit;
> + MAPTYPE map;
> +
> ebitmap_init(dst);
> - for (i=0; i < maxbit; i++) {
> - int val = ebitmap_get_bit(e1, i);
> - int rc = ebitmap_set_bit(dst, i, !val);
> - if (rc < 0)
> - return rc;
> +
> + n = e1->node;
> + for (cur_startbit = 0; cur_startbit < maxbit; cur_startbit += MAPSIZE) {
> + if (n && n->startbit == cur_startbit) {
> + startbit = n->startbit;
> + map = ~n->map;
> +
> + n = n->next;
> + } else {
> + startbit = cur_startbit;
> + map = ~((MAPTYPE) 0);
> + }
> +
> + if (maxbit - cur_startbit < MAPSIZE)
> + map &= (((MAPTYPE)1) << (maxbit - cur_startbit)) - 1;
> +
> + if (map != 0) {
> + new = malloc(sizeof(ebitmap_node_t));
> + if (!new) {
> + ebitmap_destroy(dst);
> + return -ENOMEM;
> + }
> +
> + new->startbit = startbit;
> + new->map = map;
> + new->next = NULL;
> +
> + if (prev)
> + prev->next = new;
> + else
> + dst->node = new;
> + prev = new;
> + }
> }
> +
> + if (prev)
> + dst->highbit = prev->startbit + MAPSIZE;
> +
> return 0;
> }
>
> --
> 2.36.1
>
