rebase docs: drop stray word in merge command description
[git/debian.git] / ewah / bitmap.c
blob52f1178db4ce35103545a3e1ee00a3000b08eb90
1 /**
2 * Copyright 2013, GitHub, Inc
3 * Copyright 2009-2013, Daniel Lemire, Cliff Moon,
4 * David McIntosh, Robert Becho, Google Inc. and Veronika Zenz
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version 2
9 * of the License, or (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, see <http://www.gnu.org/licenses/>.
19 #include "cache.h"
20 #include "ewok.h"
22 #define EWAH_MASK(x) ((eword_t)1 << (x % BITS_IN_EWORD))
23 #define EWAH_BLOCK(x) (x / BITS_IN_EWORD)
25 struct bitmap *bitmap_new(void)
27 struct bitmap *bitmap = xmalloc(sizeof(struct bitmap));
28 bitmap->words = xcalloc(32, sizeof(eword_t));
29 bitmap->word_alloc = 32;
30 return bitmap;
33 void bitmap_set(struct bitmap *self, size_t pos)
35 size_t block = EWAH_BLOCK(pos);
37 if (block >= self->word_alloc) {
38 size_t old_size = self->word_alloc;
39 self->word_alloc = block * 2;
40 REALLOC_ARRAY(self->words, self->word_alloc);
41 memset(self->words + old_size, 0x0,
42 (self->word_alloc - old_size) * sizeof(eword_t));
45 self->words[block] |= EWAH_MASK(pos);
48 int bitmap_get(struct bitmap *self, size_t pos)
50 size_t block = EWAH_BLOCK(pos);
51 return block < self->word_alloc &&
52 (self->words[block] & EWAH_MASK(pos)) != 0;
55 struct ewah_bitmap *bitmap_to_ewah(struct bitmap *bitmap)
57 struct ewah_bitmap *ewah = ewah_new();
58 size_t i, running_empty_words = 0;
59 eword_t last_word = 0;
61 for (i = 0; i < bitmap->word_alloc; ++i) {
62 if (bitmap->words[i] == 0) {
63 running_empty_words++;
64 continue;
67 if (last_word != 0)
68 ewah_add(ewah, last_word);
70 if (running_empty_words > 0) {
71 ewah_add_empty_words(ewah, 0, running_empty_words);
72 running_empty_words = 0;
75 last_word = bitmap->words[i];
78 ewah_add(ewah, last_word);
79 return ewah;
82 struct bitmap *ewah_to_bitmap(struct ewah_bitmap *ewah)
84 struct bitmap *bitmap = bitmap_new();
85 struct ewah_iterator it;
86 eword_t blowup;
87 size_t i = 0;
89 ewah_iterator_init(&it, ewah);
91 while (ewah_iterator_next(&blowup, &it)) {
92 ALLOC_GROW(bitmap->words, i + 1, bitmap->word_alloc);
93 bitmap->words[i++] = blowup;
96 bitmap->word_alloc = i;
97 return bitmap;
100 void bitmap_and_not(struct bitmap *self, struct bitmap *other)
102 const size_t count = (self->word_alloc < other->word_alloc) ?
103 self->word_alloc : other->word_alloc;
105 size_t i;
107 for (i = 0; i < count; ++i)
108 self->words[i] &= ~other->words[i];
111 void bitmap_or_ewah(struct bitmap *self, struct ewah_bitmap *other)
113 size_t original_size = self->word_alloc;
114 size_t other_final = (other->bit_size / BITS_IN_EWORD) + 1;
115 size_t i = 0;
116 struct ewah_iterator it;
117 eword_t word;
119 if (self->word_alloc < other_final) {
120 self->word_alloc = other_final;
121 REALLOC_ARRAY(self->words, self->word_alloc);
122 memset(self->words + original_size, 0x0,
123 (self->word_alloc - original_size) * sizeof(eword_t));
126 ewah_iterator_init(&it, other);
128 while (ewah_iterator_next(&word, &it))
129 self->words[i++] |= word;
132 size_t bitmap_popcount(struct bitmap *self)
134 size_t i, count = 0;
136 for (i = 0; i < self->word_alloc; ++i)
137 count += ewah_bit_popcount64(self->words[i]);
139 return count;
142 int bitmap_equals(struct bitmap *self, struct bitmap *other)
144 struct bitmap *big, *small;
145 size_t i;
147 if (self->word_alloc < other->word_alloc) {
148 small = self;
149 big = other;
150 } else {
151 small = other;
152 big = self;
155 for (i = 0; i < small->word_alloc; ++i) {
156 if (small->words[i] != big->words[i])
157 return 0;
160 for (; i < big->word_alloc; ++i) {
161 if (big->words[i] != 0)
162 return 0;
165 return 1;
168 void bitmap_reset(struct bitmap *bitmap)
170 memset(bitmap->words, 0x0, bitmap->word_alloc * sizeof(eword_t));
173 void bitmap_free(struct bitmap *bitmap)
175 if (bitmap == NULL)
176 return;
178 free(bitmap->words);
179 free(bitmap);