Merge branch 'ab/submodule-relative-url-tests'
[git] / ewah / bitmap.c
1 /**
2  * Copyright 2013, GitHub, Inc
3  * Copyright 2009-2013, Daniel Lemire, Cliff Moon,
4  *      David McIntosh, Robert Becho, Google Inc. and Veronika Zenz
5  *
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.
10  *
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.
15  *
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/>.
18  */
19 #include "cache.h"
20 #include "ewok.h"
21
22 #define EWAH_MASK(x) ((eword_t)1 << (x % BITS_IN_EWORD))
23 #define EWAH_BLOCK(x) (x / BITS_IN_EWORD)
24
25 struct bitmap *bitmap_new(void)
26 {
27         struct bitmap *bitmap = xmalloc(sizeof(struct bitmap));
28         bitmap->words = xcalloc(32, sizeof(eword_t));
29         bitmap->word_alloc = 32;
30         return bitmap;
31 }
32
33 void bitmap_set(struct bitmap *self, size_t pos)
34 {
35         size_t block = EWAH_BLOCK(pos);
36
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));
43         }
44
45         self->words[block] |= EWAH_MASK(pos);
46 }
47
48 int bitmap_get(struct bitmap *self, size_t pos)
49 {
50         size_t block = EWAH_BLOCK(pos);
51         return block < self->word_alloc &&
52                 (self->words[block] & EWAH_MASK(pos)) != 0;
53 }
54
55 struct ewah_bitmap *bitmap_to_ewah(struct bitmap *bitmap)
56 {
57         struct ewah_bitmap *ewah = ewah_new();
58         size_t i, running_empty_words = 0;
59         eword_t last_word = 0;
60
61         for (i = 0; i < bitmap->word_alloc; ++i) {
62                 if (bitmap->words[i] == 0) {
63                         running_empty_words++;
64                         continue;
65                 }
66
67                 if (last_word != 0)
68                         ewah_add(ewah, last_word);
69
70                 if (running_empty_words > 0) {
71                         ewah_add_empty_words(ewah, 0, running_empty_words);
72                         running_empty_words = 0;
73                 }
74
75                 last_word = bitmap->words[i];
76         }
77
78         ewah_add(ewah, last_word);
79         return ewah;
80 }
81
82 struct bitmap *ewah_to_bitmap(struct ewah_bitmap *ewah)
83 {
84         struct bitmap *bitmap = bitmap_new();
85         struct ewah_iterator it;
86         eword_t blowup;
87         size_t i = 0;
88
89         ewah_iterator_init(&it, ewah);
90
91         while (ewah_iterator_next(&blowup, &it)) {
92                 ALLOC_GROW(bitmap->words, i + 1, bitmap->word_alloc);
93                 bitmap->words[i++] = blowup;
94         }
95
96         bitmap->word_alloc = i;
97         return bitmap;
98 }
99
100 void bitmap_and_not(struct bitmap *self, struct bitmap *other)
101 {
102         const size_t count = (self->word_alloc < other->word_alloc) ?
103                 self->word_alloc : other->word_alloc;
104
105         size_t i;
106
107         for (i = 0; i < count; ++i)
108                 self->words[i] &= ~other->words[i];
109 }
110
111 void bitmap_or_ewah(struct bitmap *self, struct ewah_bitmap *other)
112 {
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;
118
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));
124         }
125
126         ewah_iterator_init(&it, other);
127
128         while (ewah_iterator_next(&word, &it))
129                 self->words[i++] |= word;
130 }
131
132 size_t bitmap_popcount(struct bitmap *self)
133 {
134         size_t i, count = 0;
135
136         for (i = 0; i < self->word_alloc; ++i)
137                 count += ewah_bit_popcount64(self->words[i]);
138
139         return count;
140 }
141
142 int bitmap_equals(struct bitmap *self, struct bitmap *other)
143 {
144         struct bitmap *big, *small;
145         size_t i;
146
147         if (self->word_alloc < other->word_alloc) {
148                 small = self;
149                 big = other;
150         } else {
151                 small = other;
152                 big = self;
153         }
154
155         for (i = 0; i < small->word_alloc; ++i) {
156                 if (small->words[i] != big->words[i])
157                         return 0;
158         }
159
160         for (; i < big->word_alloc; ++i) {
161                 if (big->words[i] != 0)
162                         return 0;
163         }
164
165         return 1;
166 }
167
168 void bitmap_reset(struct bitmap *bitmap)
169 {
170         memset(bitmap->words, 0x0, bitmap->word_alloc * sizeof(eword_t));
171 }
172
173 void bitmap_free(struct bitmap *bitmap)
174 {
175         if (bitmap == NULL)
176                 return;
177
178         free(bitmap->words);
179         free(bitmap);
180 }