[PATCH 10/13] bitmap: add bitmap_unset() function
- From
Jeff King <peff@peff.net>
- Date
- Feb 13, 2020, 02:21 UTC
- Message-ID
- <20200213022150.GJ1126038@coredump.intra.peff.net>
- In-Reply-To
- <20200213021506.GA1124607@coredump.intra.peff.net>
We've never needed to unset an individual bit in a bitmap until now. Typically they start with all bits unset and we bitmap_set() them, or we are applying another bitmap as a mask. But the easiest way to apply an object filter to a bitmap result will be to unset the individual bits.
Signed-off-by: Jeff King <peff@peff.net> --- ewah/bitmap.c | 8 ++++++++ ewah/ewok.h | 1 + 2 files changed, 9 insertions(+)
diff --git a/ewah/bitmap.c b/ewah/bitmap.c index 52f1178db4..1c31b3e249 100644 --- a/ewah/bitmap.c +++ b/ewah/bitmap.c @@ -45,6 +45,14 @@ void bitmap_set(struct bitmap *self, size_t pos) self->words[block] |= EWAH_MASK(pos); } +void bitmap_unset(struct bitmap *self, size_t pos) +{ + size_t block = EWAH_BLOCK(pos); + + if (block < self->word_alloc) + self->words[block] &= ~EWAH_MASK(pos); +} + int bitmap_get(struct bitmap *self, size_t pos) { size_t block = EWAH_BLOCK(pos); diff --git a/ewah/ewok.h b/ewah/ewok.h index 84b2a29faa..59f4ef7c4f 100644 --- a/ewah/ewok.h +++ b/ewah/ewok.h @@ -173,6 +173,7 @@ struct bitmap { struct bitmap *bitmap_new(void); void bitmap_set(struct bitmap *self, size_t pos); +void bitmap_unset(struct bitmap *self, size_t pos); int bitmap_get(struct bitmap *self, size_t pos); void bitmap_reset(struct bitmap *self); void bitmap_free(struct bitmap *self);
-- 2.25.0.785.g49bcbe7794