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Diffstat (limited to 'third_party/git/ewah/bitmap.c')
| -rw-r--r-- | third_party/git/ewah/bitmap.c | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/third_party/git/ewah/bitmap.c b/third_party/git/ewah/bitmap.c new file mode 100644 index 000000000000..52f1178db4ce --- /dev/null +++ b/third_party/git/ewah/bitmap.c @@ -0,0 +1,180 @@ +/** + * Copyright 2013, GitHub, Inc + * Copyright 2009-2013, Daniel Lemire, Cliff Moon, + * David McIntosh, Robert Becho, Google Inc. and Veronika Zenz + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, see <http://www.gnu.org/licenses/>. + */ +#include "cache.h" +#include "ewok.h" + +#define EWAH_MASK(x) ((eword_t)1 << (x % BITS_IN_EWORD)) +#define EWAH_BLOCK(x) (x / BITS_IN_EWORD) + +struct bitmap *bitmap_new(void) +{ + struct bitmap *bitmap = xmalloc(sizeof(struct bitmap)); + bitmap->words = xcalloc(32, sizeof(eword_t)); + bitmap->word_alloc = 32; + return bitmap; +} + +void bitmap_set(struct bitmap *self, size_t pos) +{ + size_t block = EWAH_BLOCK(pos); + + if (block >= self->word_alloc) { + size_t old_size = self->word_alloc; + self->word_alloc = block * 2; + REALLOC_ARRAY(self->words, self->word_alloc); + memset(self->words + old_size, 0x0, + (self->word_alloc - old_size) * sizeof(eword_t)); + } + + self->words[block] |= EWAH_MASK(pos); +} + +int bitmap_get(struct bitmap *self, size_t pos) +{ + size_t block = EWAH_BLOCK(pos); + return block < self->word_alloc && + (self->words[block] & EWAH_MASK(pos)) != 0; +} + +struct ewah_bitmap *bitmap_to_ewah(struct bitmap *bitmap) +{ + struct ewah_bitmap *ewah = ewah_new(); + size_t i, running_empty_words = 0; + eword_t last_word = 0; + + for (i = 0; i < bitmap->word_alloc; ++i) { + if (bitmap->words[i] == 0) { + running_empty_words++; + continue; + } + + if (last_word != 0) + ewah_add(ewah, last_word); + + if (running_empty_words > 0) { + ewah_add_empty_words(ewah, 0, running_empty_words); + running_empty_words = 0; + } + + last_word = bitmap->words[i]; + } + + ewah_add(ewah, last_word); + return ewah; +} + +struct bitmap *ewah_to_bitmap(struct ewah_bitmap *ewah) +{ + struct bitmap *bitmap = bitmap_new(); + struct ewah_iterator it; + eword_t blowup; + size_t i = 0; + + ewah_iterator_init(&it, ewah); + + while (ewah_iterator_next(&blowup, &it)) { + ALLOC_GROW(bitmap->words, i + 1, bitmap->word_alloc); + bitmap->words[i++] = blowup; + } + + bitmap->word_alloc = i; + return bitmap; +} + +void bitmap_and_not(struct bitmap *self, struct bitmap *other) +{ + const size_t count = (self->word_alloc < other->word_alloc) ? + self->word_alloc : other->word_alloc; + + size_t i; + + for (i = 0; i < count; ++i) + self->words[i] &= ~other->words[i]; +} + +void bitmap_or_ewah(struct bitmap *self, struct ewah_bitmap *other) +{ + size_t original_size = self->word_alloc; + size_t other_final = (other->bit_size / BITS_IN_EWORD) + 1; + size_t i = 0; + struct ewah_iterator it; + eword_t word; + + if (self->word_alloc < other_final) { + self->word_alloc = other_final; + REALLOC_ARRAY(self->words, self->word_alloc); + memset(self->words + original_size, 0x0, + (self->word_alloc - original_size) * sizeof(eword_t)); + } + + ewah_iterator_init(&it, other); + + while (ewah_iterator_next(&word, &it)) + self->words[i++] |= word; +} + +size_t bitmap_popcount(struct bitmap *self) +{ + size_t i, count = 0; + + for (i = 0; i < self->word_alloc; ++i) + count += ewah_bit_popcount64(self->words[i]); + + return count; +} + +int bitmap_equals(struct bitmap *self, struct bitmap *other) +{ + struct bitmap *big, *small; + size_t i; + + if (self->word_alloc < other->word_alloc) { + small = self; + big = other; + } else { + small = other; + big = self; + } + + for (i = 0; i < small->word_alloc; ++i) { + if (small->words[i] != big->words[i]) + return 0; + } + + for (; i < big->word_alloc; ++i) { + if (big->words[i] != 0) + return 0; + } + + return 1; +} + +void bitmap_reset(struct bitmap *bitmap) +{ + memset(bitmap->words, 0x0, bitmap->word_alloc * sizeof(eword_t)); +} + +void bitmap_free(struct bitmap *bitmap) +{ + if (bitmap == NULL) + return; + + free(bitmap->words); + free(bitmap); +} |