In a future commit, we will want to check whether or not a bitmap has
any bits set in any of its words. The best way to do this (prior to the
existence of this patch) is to call `bitmap_popcount()` and check
whether the result is non-zero.
But this is semi-wasteful, since we do not need to know the exact number
of bits set, only whether or not there is at least one of them.
Implement a new helper function to check just that.
Suggested-by: Patrick Steinhardt <ps@xxxxxx>
Signed-off-by: Taylor Blau <me@xxxxxxxxxxxx>
---
ewah/bitmap.c | 9 +++++++++
ewah/ewok.h | 1 +
2 files changed, 10 insertions(+)
diff --git a/ewah/bitmap.c b/ewah/bitmap.c
index 7b525b1ecd..ac7e0af622 100644
--- a/ewah/bitmap.c
+++ b/ewah/bitmap.c
@@ -169,6 +169,15 @@ size_t bitmap_popcount(struct bitmap *self)
return count;
}
+int bitmap_is_empty(struct bitmap *self)
+{
+ size_t i;
+ for (i = 0; i < self->word_alloc; i++)
+ if (self->words[i])
+ return 0;
+ return 1;
+}
+
int bitmap_equals(struct bitmap *self, struct bitmap *other)
{
struct bitmap *big, *small;
diff --git a/ewah/ewok.h b/ewah/ewok.h
index 7eb8b9b630..c11d76c6f3 100644
--- a/ewah/ewok.h
+++ b/ewah/ewok.h
@@ -189,5 +189,6 @@ void bitmap_or_ewah(struct bitmap *self, struct ewah_bitmap *other);
void bitmap_or(struct bitmap *self, const struct bitmap *other);
size_t bitmap_popcount(struct bitmap *self);
+int bitmap_is_empty(struct bitmap *self);
#endif
--
2.43.0.102.ga31d690331.dirty
