bed1994551cd03532fe56913b0e27343834c805f
[git/git.git] / ewah / ewah_io.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 "git-compat-util.h"
20 #include "ewok.h"
21 #include "strbuf.h"
22
23 int ewah_serialize_native(struct ewah_bitmap *self, int fd)
24 {
25 uint32_t write32;
26 size_t to_write = self->buffer_size * 8;
27
28 /* 32 bit -- bit size for the map */
29 write32 = (uint32_t)self->bit_size;
30 if (write(fd, &write32, 4) != 4)
31 return -1;
32
33 /** 32 bit -- number of compressed 64-bit words */
34 write32 = (uint32_t)self->buffer_size;
35 if (write(fd, &write32, 4) != 4)
36 return -1;
37
38 if (write(fd, self->buffer, to_write) != to_write)
39 return -1;
40
41 /** 32 bit -- position for the RLW */
42 write32 = self->rlw - self->buffer;
43 if (write(fd, &write32, 4) != 4)
44 return -1;
45
46 return (3 * 4) + to_write;
47 }
48
49 int ewah_serialize_to(struct ewah_bitmap *self,
50 int (*write_fun)(void *, const void *, size_t),
51 void *data)
52 {
53 size_t i;
54 eword_t dump[2048];
55 const size_t words_per_dump = sizeof(dump) / sizeof(eword_t);
56 uint32_t bitsize, word_count, rlw_pos;
57
58 const eword_t *buffer;
59 size_t words_left;
60
61 /* 32 bit -- bit size for the map */
62 bitsize = htonl((uint32_t)self->bit_size);
63 if (write_fun(data, &bitsize, 4) != 4)
64 return -1;
65
66 /** 32 bit -- number of compressed 64-bit words */
67 word_count = htonl((uint32_t)self->buffer_size);
68 if (write_fun(data, &word_count, 4) != 4)
69 return -1;
70
71 /** 64 bit x N -- compressed words */
72 buffer = self->buffer;
73 words_left = self->buffer_size;
74
75 while (words_left >= words_per_dump) {
76 for (i = 0; i < words_per_dump; ++i, ++buffer)
77 dump[i] = htonll(*buffer);
78
79 if (write_fun(data, dump, sizeof(dump)) != sizeof(dump))
80 return -1;
81
82 words_left -= words_per_dump;
83 }
84
85 if (words_left) {
86 for (i = 0; i < words_left; ++i, ++buffer)
87 dump[i] = htonll(*buffer);
88
89 if (write_fun(data, dump, words_left * 8) != words_left * 8)
90 return -1;
91 }
92
93 /** 32 bit -- position for the RLW */
94 rlw_pos = (uint8_t*)self->rlw - (uint8_t *)self->buffer;
95 rlw_pos = htonl(rlw_pos / sizeof(eword_t));
96
97 if (write_fun(data, &rlw_pos, 4) != 4)
98 return -1;
99
100 return (3 * 4) + (self->buffer_size * 8);
101 }
102
103 static int write_helper(void *fd, const void *buf, size_t len)
104 {
105 return write((intptr_t)fd, buf, len);
106 }
107
108 int ewah_serialize(struct ewah_bitmap *self, int fd)
109 {
110 return ewah_serialize_to(self, write_helper, (void *)(intptr_t)fd);
111 }
112
113 static int write_strbuf(void *user_data, const void *data, size_t len)
114 {
115 struct strbuf *sb = user_data;
116 strbuf_add(sb, data, len);
117 return len;
118 }
119
120 int ewah_serialize_strbuf(struct ewah_bitmap *self, struct strbuf *sb)
121 {
122 return ewah_serialize_to(self, write_strbuf, sb);
123 }
124
125 int ewah_read_mmap(struct ewah_bitmap *self, const void *map, size_t len)
126 {
127 const uint8_t *ptr = map;
128 size_t i;
129
130 self->bit_size = get_be32(ptr);
131 ptr += sizeof(uint32_t);
132
133 self->buffer_size = self->alloc_size = get_be32(ptr);
134 ptr += sizeof(uint32_t);
135
136 REALLOC_ARRAY(self->buffer, self->alloc_size);
137
138 /*
139 * Copy the raw data for the bitmap as a whole chunk;
140 * if we're in a little-endian platform, we'll perform
141 * the endianness conversion in a separate pass to ensure
142 * we're loading 8-byte aligned words.
143 */
144 memcpy(self->buffer, ptr, self->buffer_size * sizeof(eword_t));
145 ptr += self->buffer_size * sizeof(eword_t);
146
147 for (i = 0; i < self->buffer_size; ++i)
148 self->buffer[i] = ntohll(self->buffer[i]);
149
150 self->rlw = self->buffer + get_be32(ptr);
151
152 return (3 * 4) + (self->buffer_size * 8);
153 }
154
155 int ewah_deserialize(struct ewah_bitmap *self, int fd)
156 {
157 size_t i;
158 eword_t dump[2048];
159 const size_t words_per_dump = sizeof(dump) / sizeof(eword_t);
160 uint32_t bitsize, word_count, rlw_pos;
161
162 eword_t *buffer = NULL;
163 size_t words_left;
164
165 ewah_clear(self);
166
167 /* 32 bit -- bit size for the map */
168 if (read(fd, &bitsize, 4) != 4)
169 return -1;
170
171 self->bit_size = (size_t)ntohl(bitsize);
172
173 /** 32 bit -- number of compressed 64-bit words */
174 if (read(fd, &word_count, 4) != 4)
175 return -1;
176
177 self->buffer_size = self->alloc_size = (size_t)ntohl(word_count);
178 REALLOC_ARRAY(self->buffer, self->alloc_size);
179
180 /** 64 bit x N -- compressed words */
181 buffer = self->buffer;
182 words_left = self->buffer_size;
183
184 while (words_left >= words_per_dump) {
185 if (read(fd, dump, sizeof(dump)) != sizeof(dump))
186 return -1;
187
188 for (i = 0; i < words_per_dump; ++i, ++buffer)
189 *buffer = ntohll(dump[i]);
190
191 words_left -= words_per_dump;
192 }
193
194 if (words_left) {
195 if (read(fd, dump, words_left * 8) != words_left * 8)
196 return -1;
197
198 for (i = 0; i < words_left; ++i, ++buffer)
199 *buffer = ntohll(dump[i]);
200 }
201
202 /** 32 bit -- position for the RLW */
203 if (read(fd, &rlw_pos, 4) != 4)
204 return -1;
205
206 self->rlw = self->buffer + ntohl(rlw_pos);
207 return 0;
208 }