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/* membuf.c - A simple implementation of a dynamic buffer
* Copyright (C) 2001, 2003 Free Software Foundation, Inc.
*
* This file is part of GnuPG.
*
* GnuPG 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 3 of the License, or
* (at your option) any later version.
*
* GnuPG 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 <config.h>
#include <stdlib.h>
#include <errno.h>
#include "membuf.h"
#include "util.h"
/* A simple implementation of a dynamic buffer. Use init_membuf() to
create a buffer, put_membuf to append bytes and get_membuf to
release and return the buffer. Allocation errors are detected but
only returned at the final get_membuf(), this helps not to clutter
the code with out of core checks. */
void
init_membuf (membuf_t *mb, int initiallen)
{
mb->len = 0;
mb->size = initiallen;
mb->out_of_core = 0;
mb->buf = xtrymalloc (initiallen);
if (!mb->buf)
mb->out_of_core = errno;
}
/* Same as init_membuf but allocates the buffer in secure memory. */
void
init_membuf_secure (membuf_t *mb, int initiallen)
{
mb->len = 0;
mb->size = initiallen;
mb->out_of_core = 0;
mb->buf = xtrymalloc_secure (initiallen);
if (!mb->buf)
mb->out_of_core = errno;
}
void
put_membuf (membuf_t *mb, const void *buf, size_t len)
{
if (mb->out_of_core)
return;
if (mb->len + len >= mb->size)
{
char *p;
mb->size += len + 1024;
p = xtryrealloc (mb->buf, mb->size);
if (!p)
{
mb->out_of_core = errno ? errno : ENOMEM;
/* Wipe out what we already accumulated. This is required
in case we are storing sensitive data here. The membuf
API does not provide another way to cleanup after an
error. */
memset (mb->buf, 0, mb->len);
return;
}
mb->buf = p;
}
memcpy (mb->buf + mb->len, buf, len);
mb->len += len;
}
void
put_membuf_str (membuf_t *mb, const char *string)
{
put_membuf (mb, string, strlen (string));
}
void *
get_membuf (membuf_t *mb, size_t *len)
{
char *p;
if (mb->out_of_core)
{
xfree (mb->buf);
mb->buf = NULL;
errno = mb->out_of_core;
return NULL;
}
p = mb->buf;
if (len)
*len = mb->len;
mb->buf = NULL;
mb->out_of_core = ENOMEM; /* hack to make sure it won't get reused. */
return p;
}
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