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![Jeff King](/assets/img/avatar_default.png)
Now that we're built around xmalloc and friends, we can use helpers like REALLOC_ARRAY, ALLOC_GROW, and so on to make the code shorter and protect against integer overflow. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
214 lines
4.9 KiB
C
214 lines
4.9 KiB
C
/**
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* Copyright 2013, GitHub, Inc
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* Copyright 2009-2013, Daniel Lemire, Cliff Moon,
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* David McIntosh, Robert Becho, Google Inc. and Veronika Zenz
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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#include "cache.h"
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#include "ewok.h"
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#define EWAH_MASK(x) ((eword_t)1 << (x % BITS_IN_EWORD))
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#define EWAH_BLOCK(x) (x / BITS_IN_EWORD)
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struct bitmap *bitmap_new(void)
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{
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struct bitmap *bitmap = xmalloc(sizeof(struct bitmap));
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bitmap->words = xcalloc(32, sizeof(eword_t));
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bitmap->word_alloc = 32;
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return bitmap;
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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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if (block >= self->word_alloc) {
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size_t old_size = self->word_alloc;
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self->word_alloc = block * 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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self->words[block] |= EWAH_MASK(pos);
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}
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void bitmap_clear(struct bitmap *self, size_t pos)
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{
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size_t block = EWAH_BLOCK(pos);
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if (block < self->word_alloc)
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self->words[block] &= ~EWAH_MASK(pos);
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}
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int bitmap_get(struct bitmap *self, size_t pos)
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{
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size_t block = EWAH_BLOCK(pos);
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return block < self->word_alloc &&
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(self->words[block] & EWAH_MASK(pos)) != 0;
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}
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struct ewah_bitmap *bitmap_to_ewah(struct bitmap *bitmap)
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{
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struct ewah_bitmap *ewah = ewah_new();
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size_t i, running_empty_words = 0;
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eword_t last_word = 0;
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for (i = 0; i < bitmap->word_alloc; ++i) {
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if (bitmap->words[i] == 0) {
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running_empty_words++;
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continue;
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}
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if (last_word != 0)
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ewah_add(ewah, last_word);
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if (running_empty_words > 0) {
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ewah_add_empty_words(ewah, 0, running_empty_words);
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running_empty_words = 0;
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}
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last_word = bitmap->words[i];
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}
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ewah_add(ewah, last_word);
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return ewah;
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}
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struct bitmap *ewah_to_bitmap(struct ewah_bitmap *ewah)
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{
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struct bitmap *bitmap = bitmap_new();
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struct ewah_iterator it;
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eword_t blowup;
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size_t i = 0;
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ewah_iterator_init(&it, ewah);
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while (ewah_iterator_next(&blowup, &it)) {
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ALLOC_GROW(bitmap->words, i + 1, bitmap->word_alloc);
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bitmap->words[i++] = blowup;
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}
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bitmap->word_alloc = i;
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return bitmap;
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}
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void bitmap_and_not(struct bitmap *self, struct bitmap *other)
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{
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const size_t count = (self->word_alloc < other->word_alloc) ?
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self->word_alloc : other->word_alloc;
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size_t i;
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for (i = 0; i < count; ++i)
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self->words[i] &= ~other->words[i];
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}
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void bitmap_or_ewah(struct bitmap *self, struct ewah_bitmap *other)
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{
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size_t original_size = self->word_alloc;
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size_t other_final = (other->bit_size / BITS_IN_EWORD) + 1;
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size_t i = 0;
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struct ewah_iterator it;
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eword_t word;
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if (self->word_alloc < other_final) {
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self->word_alloc = other_final;
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REALLOC_ARRAY(self->words, self->word_alloc);
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memset(self->words + original_size, 0x0,
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(self->word_alloc - original_size) * sizeof(eword_t));
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}
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ewah_iterator_init(&it, other);
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while (ewah_iterator_next(&word, &it))
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self->words[i++] |= word;
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}
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void bitmap_each_bit(struct bitmap *self, ewah_callback callback, void *data)
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{
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size_t pos = 0, i;
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for (i = 0; i < self->word_alloc; ++i) {
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eword_t word = self->words[i];
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uint32_t offset;
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if (word == (eword_t)~0) {
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for (offset = 0; offset < BITS_IN_EWORD; ++offset)
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callback(pos++, data);
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} else {
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for (offset = 0; offset < BITS_IN_EWORD; ++offset) {
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if ((word >> offset) == 0)
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break;
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offset += ewah_bit_ctz64(word >> offset);
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callback(pos + offset, data);
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}
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pos += BITS_IN_EWORD;
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}
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}
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}
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size_t bitmap_popcount(struct bitmap *self)
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{
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size_t i, count = 0;
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for (i = 0; i < self->word_alloc; ++i)
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count += ewah_bit_popcount64(self->words[i]);
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return count;
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}
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int bitmap_equals(struct bitmap *self, struct bitmap *other)
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{
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struct bitmap *big, *small;
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size_t i;
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if (self->word_alloc < other->word_alloc) {
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small = self;
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big = other;
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} else {
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small = other;
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big = self;
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}
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for (i = 0; i < small->word_alloc; ++i) {
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if (small->words[i] != big->words[i])
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return 0;
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}
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for (; i < big->word_alloc; ++i) {
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if (big->words[i] != 0)
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return 0;
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}
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return 1;
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}
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void bitmap_reset(struct bitmap *bitmap)
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{
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memset(bitmap->words, 0x0, bitmap->word_alloc * sizeof(eword_t));
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}
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void bitmap_free(struct bitmap *bitmap)
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{
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if (bitmap == NULL)
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return;
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free(bitmap->words);
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free(bitmap);
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}
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