ewah: factor out bitmap growth
We auto-grow bitmaps when somebody asks to set a bit whose position is outside of our currently allocated range. Other operations besides single bit-setting might need to do this, too, so let's pull it into its own function. Note that we change the semantics a little: you now ask for the number of words you'd like to have, not the id of the block you'd like to write to. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Jeff King committed
Dec 8, 2020 at 17:03 UTC
d574bf43e806e0d4d6cda7c2f5d016a87843078f
1 file changed
+9
-5
ewah/bitmap.c
+9
-5
@@ -35,18 +35,22 @@ struct bitmap *bitmap_new(void)
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return bitmap_word_alloc(32);
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}
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-void bitmap_set(struct bitmap *self, size_t pos)
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+static void bitmap_grow(struct bitmap *self, size_t word_alloc)
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{
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- size_t block = EWAH_BLOCK(pos);
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-
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- if (block >= self->word_alloc) {
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+ if (word_alloc > self->word_alloc) {
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size_t old_size = self->word_alloc;
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- self->word_alloc = block ? block * 2 : 1;
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+ self->word_alloc = word_alloc * 2;
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REALLOC_ARRAY(self->words, self->word_alloc);
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memset(self->words + old_size, 0x0,
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(self->word_alloc - old_size) * sizeof(eword_t));
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}
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+}
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+
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+void bitmap_set(struct bitmap *self, size_t pos)
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+{
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+ size_t block = EWAH_BLOCK(pos);
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+ bitmap_grow(self, block + 1);
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self->words[block] |= EWAH_MASK(pos);
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}
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