1 /* membuf.c - A simple implementation of a dynamic buffer
2 * Copyright (C) 2001, 2003 Free Software Foundation, Inc.
3 *
4 * This file is part of GnuPG.
5 *
6 * GnuPG is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 3 of the License, or
9 * (at your option) any later version.
10 *
11 * GnuPG 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
20 #include <config.h>
21 #include <stdlib.h>
22 #include <string.h>
23 #include <errno.h>
24
25 #include <glib.h>
26
27 #include "membuf.h"
28
29
30 /* A simple implementation of a dynamic buffer. Use init_membuf() to
31 create a buffer, put_membuf to append bytes and get_membuf to
32 release and return the buffer. Allocation errors are detected but
33 only returned at the final get_membuf(), this helps not to clutter
34 the code with out of core checks. */
35 void
init_membuf(membuf_t * mb,size_t initiallen)36 init_membuf (membuf_t *mb, size_t initiallen)
37 {
38 if (!initiallen)
39 initiallen = 1024;
40 mb->len = 0;
41 mb->size = initiallen;
42 mb->out_of_core = 0;
43 mb->buf = g_try_malloc (initiallen);
44 if (!mb->buf)
45 mb->out_of_core = errno;
46 }
47
48
49 void
put_membuf(membuf_t * mb,const void * buf,size_t len)50 put_membuf (membuf_t *mb, const void *buf, size_t len)
51 {
52 if (mb->out_of_core)
53 return;
54
55 if (mb->len + len >= mb->size)
56 {
57 char *p;
58
59 mb->size += len + 1024;
60 p = g_try_realloc (mb->buf, mb->size);
61 if (!p)
62 {
63 mb->out_of_core = errno ? errno : ENOMEM;
64 /* Wipe out what we already accumulated. This is required
65 in case we are storing sensitive data here. The membuf
66 API does not provide another way to cleanup after an
67 error. */
68 memset (mb->buf, 0, mb->len);
69 return;
70 }
71 mb->buf = p;
72 }
73 memcpy (mb->buf + mb->len, buf, len);
74 mb->len += len;
75 }
76
77
78 void
put_membuf_str(membuf_t * mb,const char * string)79 put_membuf_str (membuf_t *mb, const char *string)
80 {
81 put_membuf (mb, string, strlen (string));
82 }
83
84
85 void *
get_membuf(membuf_t * mb,size_t * len)86 get_membuf (membuf_t *mb, size_t *len)
87 {
88 char *p;
89
90 if (mb->out_of_core)
91 {
92 g_free (mb->buf);
93 mb->buf = NULL;
94 errno = mb->out_of_core;
95 return NULL;
96 }
97
98 p = mb->buf;
99 if (len)
100 *len = mb->len;
101 mb->buf = NULL;
102 mb->out_of_core = ENOMEM; /* Hack to make sure it won't get reused. */
103 return p;
104 }
105