about summary refs log tree commit diff
path: root/ewah/ewah_io.c
blob: 9035ee65ea8db67c373492fcb1755f8b1499679e (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
/**
 * Copyright 2013, GitHub, Inc
 * Copyright 2009-2013, Daniel Lemire, Cliff Moon,
 *	David McIntosh, Robert Becho, Google Inc. and Veronika Zenz
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see <http://www.gnu.org/licenses/>.
 */
#include "git-compat-util.h"
#include "ewok.h"
#include "strbuf.h"

int ewah_serialize_to(struct ewah_bitmap *self,
		      int (*write_fun)(void *, const void *, size_t),
		      void *data)
{
	size_t i;
	eword_t dump[2048];
	const size_t words_per_dump = sizeof(dump) / sizeof(eword_t);
	uint32_t bitsize, word_count, rlw_pos;

	const eword_t *buffer;
	size_t words_left;

	/* 32 bit -- bit size for the map */
	bitsize =  htonl((uint32_t)self->bit_size);
	if (write_fun(data, &bitsize, 4) != 4)
		return -1;

	/** 32 bit -- number of compressed 64-bit words */
	word_count =  htonl((uint32_t)self->buffer_size);
	if (write_fun(data, &word_count, 4) != 4)
		return -1;

	/** 64 bit x N -- compressed words */
	buffer = self->buffer;
	words_left = self->buffer_size;

	while (words_left >= words_per_dump) {
		for (i = 0; i < words_per_dump; ++i, ++buffer)
			dump[i] = htonll(*buffer);

		if (write_fun(data, dump, sizeof(dump)) != sizeof(dump))
			return -1;

		words_left -= words_per_dump;
	}

	if (words_left) {
		for (i = 0; i < words_left; ++i, ++buffer)
			dump[i] = htonll(*buffer);

		if (write_fun(data, dump, words_left * 8) != words_left * 8)
			return -1;
	}

	/** 32 bit -- position for the RLW */
	rlw_pos = (uint8_t*)self->rlw - (uint8_t *)self->buffer;
	rlw_pos = htonl(rlw_pos / sizeof(eword_t));

	if (write_fun(data, &rlw_pos, 4) != 4)
		return -1;

	return (3 * 4) + (self->buffer_size * 8);
}

static int write_strbuf(void *user_data, const void *data, size_t len)
{
	struct strbuf *sb = user_data;
	strbuf_add(sb, data, len);
	return len;
}

int ewah_serialize_strbuf(struct ewah_bitmap *self, struct strbuf *sb)
{
	return ewah_serialize_to(self, write_strbuf, sb);
}

ssize_t ewah_read_mmap(struct ewah_bitmap *self, const void *map, size_t len)
{
	const uint8_t *ptr = map;
	size_t data_len;
	size_t i;

	if (len < sizeof(uint32_t))
		return error("corrupt ewah bitmap: eof before bit size");
	self->bit_size = get_be32(ptr);
	ptr += sizeof(uint32_t);
	len -= sizeof(uint32_t);

	if (len < sizeof(uint32_t))
		return error("corrupt ewah bitmap: eof before length");
	self->buffer_size = self->alloc_size = get_be32(ptr);
	ptr += sizeof(uint32_t);
	len -= sizeof(uint32_t);

	REALLOC_ARRAY(self->buffer, self->alloc_size);

	/*
	 * Copy the raw data for the bitmap as a whole chunk;
	 * if we're in a little-endian platform, we'll perform
	 * the endianness conversion in a separate pass to ensure
	 * we're loading 8-byte aligned words.
	 */
	data_len = st_mult(self->buffer_size, sizeof(eword_t));
	if (len < data_len)
		return error("corrupt ewah bitmap: eof in data "
			     "(%"PRIuMAX" bytes short)",
			     (uintmax_t)(data_len - len));
	memcpy(self->buffer, ptr, data_len);
	ptr += data_len;
	len -= data_len;

	for (i = 0; i < self->buffer_size; ++i)
		self->buffer[i] = ntohll(self->buffer[i]);

	if (len < sizeof(uint32_t))
		return error("corrupt ewah bitmap: eof before rlw");
	self->rlw = self->buffer + get_be32(ptr);
	ptr += sizeof(uint32_t);
	len -= sizeof(uint32_t);

	return ptr - (const uint8_t *)map;
}