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git/ewah/bitmap.c

226 lines
5.0 KiB

/**
* 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_word_alloc(size_t word_alloc)
{
struct bitmap *bitmap = xmalloc(sizeof(struct bitmap));
CALLOC_ARRAY(bitmap->words, word_alloc);
bitmap->word_alloc = word_alloc;
return bitmap;
}
struct bitmap *bitmap_new(void)
{
return bitmap_word_alloc(32);
}
struct bitmap *bitmap_dup(const struct bitmap *src)
{
struct bitmap *dst = bitmap_word_alloc(src->word_alloc);
COPY_ARRAY(dst->words, src->words, src->word_alloc);
return dst;
}
static void bitmap_grow(struct bitmap *self, size_t word_alloc)
{
size_t old_size = self->word_alloc;
ALLOC_GROW(self->words, word_alloc, self->word_alloc);
memset(self->words + old_size, 0x0,
(self->word_alloc - old_size) * sizeof(eword_t));
}
void bitmap_set(struct bitmap *self, size_t pos)
{
size_t block = EWAH_BLOCK(pos);
bitmap_grow(self, block + 1);
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);
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(struct bitmap *self, const struct bitmap *other)
{
size_t i;
bitmap_grow(self, other->word_alloc);
for (i = 0; i < other->word_alloc; 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;
}
int bitmap_is_subset(struct bitmap *self, struct bitmap *other)
{
size_t common_size, i;
if (self->word_alloc < other->word_alloc)
common_size = self->word_alloc;
else {
common_size = other->word_alloc;
for (i = common_size; i < self->word_alloc; i++) {
if (self->words[i])
return 1;
}
}
for (i = 0; i < common_size; i++) {
if (self->words[i] & ~other->words[i])
return 1;
}
return 0;
}
void bitmap_free(struct bitmap *bitmap)
{
if (!bitmap)
return;
free(bitmap->words);
free(bitmap);
}