stash: remove now superfluos help for "stash push"
[git.git] / ewah / bitmap.c
blob7103ceefbff6768042161345565bb773ab6b8d30
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, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
20 #include "cache.h"
21 #include "ewok.h"
23 #define EWAH_MASK(x) ((eword_t)1 << (x % BITS_IN_EWORD))
24 #define EWAH_BLOCK(x) (x / BITS_IN_EWORD)
26 struct bitmap *bitmap_new(void)
28 struct bitmap *bitmap = xmalloc(sizeof(struct bitmap));
29 bitmap->words = xcalloc(32, sizeof(eword_t));
30 bitmap->word_alloc = 32;
31 return bitmap;
34 void bitmap_set(struct bitmap *self, size_t pos)
36 size_t block = EWAH_BLOCK(pos);
38 if (block >= self->word_alloc) {
39 size_t old_size = self->word_alloc;
40 self->word_alloc = block * 2;
41 REALLOC_ARRAY(self->words, self->word_alloc);
42 memset(self->words + old_size, 0x0,
43 (self->word_alloc - old_size) * sizeof(eword_t));
46 self->words[block] |= EWAH_MASK(pos);
49 void bitmap_clear(struct bitmap *self, size_t pos)
51 size_t block = EWAH_BLOCK(pos);
53 if (block < self->word_alloc)
54 self->words[block] &= ~EWAH_MASK(pos);
57 int bitmap_get(struct bitmap *self, size_t pos)
59 size_t block = EWAH_BLOCK(pos);
60 return block < self->word_alloc &&
61 (self->words[block] & EWAH_MASK(pos)) != 0;
64 struct ewah_bitmap *bitmap_to_ewah(struct bitmap *bitmap)
66 struct ewah_bitmap *ewah = ewah_new();
67 size_t i, running_empty_words = 0;
68 eword_t last_word = 0;
70 for (i = 0; i < bitmap->word_alloc; ++i) {
71 if (bitmap->words[i] == 0) {
72 running_empty_words++;
73 continue;
76 if (last_word != 0)
77 ewah_add(ewah, last_word);
79 if (running_empty_words > 0) {
80 ewah_add_empty_words(ewah, 0, running_empty_words);
81 running_empty_words = 0;
84 last_word = bitmap->words[i];
87 ewah_add(ewah, last_word);
88 return ewah;
91 struct bitmap *ewah_to_bitmap(struct ewah_bitmap *ewah)
93 struct bitmap *bitmap = bitmap_new();
94 struct ewah_iterator it;
95 eword_t blowup;
96 size_t i = 0;
98 ewah_iterator_init(&it, ewah);
100 while (ewah_iterator_next(&blowup, &it)) {
101 ALLOC_GROW(bitmap->words, i + 1, bitmap->word_alloc);
102 bitmap->words[i++] = blowup;
105 bitmap->word_alloc = i;
106 return bitmap;
109 void bitmap_and_not(struct bitmap *self, struct bitmap *other)
111 const size_t count = (self->word_alloc < other->word_alloc) ?
112 self->word_alloc : other->word_alloc;
114 size_t i;
116 for (i = 0; i < count; ++i)
117 self->words[i] &= ~other->words[i];
120 void bitmap_or_ewah(struct bitmap *self, struct ewah_bitmap *other)
122 size_t original_size = self->word_alloc;
123 size_t other_final = (other->bit_size / BITS_IN_EWORD) + 1;
124 size_t i = 0;
125 struct ewah_iterator it;
126 eword_t word;
128 if (self->word_alloc < other_final) {
129 self->word_alloc = other_final;
130 REALLOC_ARRAY(self->words, self->word_alloc);
131 memset(self->words + original_size, 0x0,
132 (self->word_alloc - original_size) * sizeof(eword_t));
135 ewah_iterator_init(&it, other);
137 while (ewah_iterator_next(&word, &it))
138 self->words[i++] |= word;
141 void bitmap_each_bit(struct bitmap *self, ewah_callback callback, void *data)
143 size_t pos = 0, i;
145 for (i = 0; i < self->word_alloc; ++i) {
146 eword_t word = self->words[i];
147 uint32_t offset;
149 if (word == (eword_t)~0) {
150 for (offset = 0; offset < BITS_IN_EWORD; ++offset)
151 callback(pos++, data);
152 } else {
153 for (offset = 0; offset < BITS_IN_EWORD; ++offset) {
154 if ((word >> offset) == 0)
155 break;
157 offset += ewah_bit_ctz64(word >> offset);
158 callback(pos + offset, data);
160 pos += BITS_IN_EWORD;
165 size_t bitmap_popcount(struct bitmap *self)
167 size_t i, count = 0;
169 for (i = 0; i < self->word_alloc; ++i)
170 count += ewah_bit_popcount64(self->words[i]);
172 return count;
175 int bitmap_equals(struct bitmap *self, struct bitmap *other)
177 struct bitmap *big, *small;
178 size_t i;
180 if (self->word_alloc < other->word_alloc) {
181 small = self;
182 big = other;
183 } else {
184 small = other;
185 big = self;
188 for (i = 0; i < small->word_alloc; ++i) {
189 if (small->words[i] != big->words[i])
190 return 0;
193 for (; i < big->word_alloc; ++i) {
194 if (big->words[i] != 0)
195 return 0;
198 return 1;
201 void bitmap_reset(struct bitmap *bitmap)
203 memset(bitmap->words, 0x0, bitmap->word_alloc * sizeof(eword_t));
206 void bitmap_free(struct bitmap *bitmap)
208 if (bitmap == NULL)
209 return;
211 free(bitmap->words);
212 free(bitmap);