range: Introduce range_inverse_array()
This helper reverses a list of regions within a [low, high] span, turning original regions into holes and original holes into actual regions, covering the whole UINT64_MAX span. Signed-off-by: Eric Auger <eric.auger@redhat.com> Tested-by: Yanghang Liu <yanghliu@redhat.com> Reviewed-by: "Michael S. Tsirkin" <mst@redhat.com> Signed-off-by: Cédric Le Goater <clg@redhat.com>
This commit is contained in:
parent
908cae0de4
commit
b439595a08
|
@ -225,4 +225,12 @@ int range_compare(Range *a, Range *b);
|
|||
|
||||
GList *range_list_insert(GList *list, Range *data);
|
||||
|
||||
/*
|
||||
* Inverse an array of sorted ranges over the [low, high] span, ie.
|
||||
* original ranges becomes holes in the newly allocated inv_ranges
|
||||
*/
|
||||
void range_inverse_array(GList *in_ranges,
|
||||
GList **out_ranges,
|
||||
uint64_t low, uint64_t high);
|
||||
|
||||
#endif
|
||||
|
|
55
util/range.c
55
util/range.c
|
@ -66,3 +66,58 @@ GList *range_list_insert(GList *list, Range *data)
|
|||
|
||||
return list;
|
||||
}
|
||||
|
||||
static inline
|
||||
GList *append_new_range(GList *list, uint64_t lob, uint64_t upb)
|
||||
{
|
||||
Range *new = g_new0(Range, 1);
|
||||
|
||||
range_set_bounds(new, lob, upb);
|
||||
return g_list_append(list, new);
|
||||
}
|
||||
|
||||
|
||||
void range_inverse_array(GList *in, GList **rev,
|
||||
uint64_t low, uint64_t high)
|
||||
{
|
||||
Range *r, *rn;
|
||||
GList *l = in, *out = *rev;
|
||||
|
||||
for (l = in; l && range_upb(l->data) < low; l = l->next) {
|
||||
continue;
|
||||
}
|
||||
|
||||
if (!l) {
|
||||
out = append_new_range(out, low, high);
|
||||
goto exit;
|
||||
}
|
||||
r = (Range *)l->data;
|
||||
|
||||
/* first range lob is greater than min, insert a first range */
|
||||
if (range_lob(r) > low) {
|
||||
out = append_new_range(out, low, MIN(range_lob(r) - 1, high));
|
||||
}
|
||||
|
||||
/* insert a range inbetween each original range until we reach high */
|
||||
for (; l->next; l = l->next) {
|
||||
r = (Range *)l->data;
|
||||
rn = (Range *)l->next->data;
|
||||
if (range_lob(r) >= high) {
|
||||
goto exit;
|
||||
}
|
||||
if (range_compare(r, rn)) {
|
||||
out = append_new_range(out, range_upb(r) + 1,
|
||||
MIN(range_lob(rn) - 1, high));
|
||||
}
|
||||
}
|
||||
|
||||
/* last range */
|
||||
r = (Range *)l->data;
|
||||
|
||||
/* last range upb is less than max, insert a last range */
|
||||
if (range_upb(r) < high) {
|
||||
out = append_new_range(out, range_upb(r) + 1, high);
|
||||
}
|
||||
exit:
|
||||
*rev = out;
|
||||
}
|
||||
|
|
Loading…
Reference in New Issue