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
|
/* $OpenBSD: dba_write.c,v 1.1 2016/08/01 10:32:39 schwarze Exp $ */
/*
* Copyright (c) 2016 Ingo Schwarze <schwarze@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
* Low-level functions for serializing allocation-based data to disk.
* The interface is defined in "dba_write.h".
*/
#include <assert.h>
#include <endian.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <stdint.h>
#include <stdio.h>
#include "dba_write.h"
static FILE *ofp;
int
dba_open(const char *fname)
{
ofp = fopen(fname, "w");
return ofp == NULL ? -1 : 0;
}
int
dba_close(void)
{
return fclose(ofp) == EOF ? -1 : 0;
}
int32_t
dba_tell(void)
{
long pos;
if ((pos = ftell(ofp)) == -1)
err(1, "ftell");
if (pos >= INT32_MAX) {
errno = EOVERFLOW;
err(1, "ftell = %ld", pos);
}
return pos;
}
void
dba_seek(int32_t pos)
{
if (fseek(ofp, pos, SEEK_SET) == -1)
err(1, "fseek(%d)", pos);
}
int32_t
dba_align(void)
{
int32_t pos;
pos = dba_tell();
while (pos & 3) {
dba_char_write('\0');
pos++;
}
return pos;
}
int32_t
dba_skip(int32_t nmemb, int32_t sz)
{
const int32_t out[5] = {0, 0, 0, 0, 0};
int32_t i, pos;
assert(sz >= 0);
assert(nmemb > 0);
assert(nmemb <= 5);
pos = dba_tell();
for (i = 0; i < sz; i++)
if (nmemb - fwrite(&out, sizeof(out[0]), nmemb, ofp))
err(1, "fwrite");
return pos;
}
void
dba_char_write(int c)
{
if (putc(c, ofp) == EOF)
err(1, "fputc");
}
void
dba_str_write(const char *str)
{
if (fputs(str, ofp) == EOF)
err(1, "fputs");
dba_char_write('\0');
}
void
dba_int_write(int32_t i)
{
i = htobe32(i);
if (fwrite(&i, sizeof(i), 1, ofp) != 1)
err(1, "fwrite");
}
|
