From e5d48bf38bc0e1f44f4daa7c8e0f75cd9296d020 Mon Sep 17 00:00:00 2001 From: Taylor Blau Date: Thu, 14 Dec 2023 17:23:59 -0500 Subject: ewah: implement `bitmap_is_empty()` 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 Signed-off-by: Taylor Blau Signed-off-by: Junio C Hamano --- ewah/bitmap.c | 9 +++++++++ ewah/ewok.h | 1 + 2 files changed, 10 insertions(+) (limited to 'ewah') 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 -- cgit v1.2.3