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mirror of git://git.gnupg.org/gnupg.git synced 2024-12-22 10:19:57 +01:00
gnupg/g13/utils.c
Werner Koch b008274afd Nuked almost all trailing white space.
We better do this once and for all instead of cluttering all future
commits with diffs of trailing white spaces.  In the majority of cases
blank or single lines are affected and thus this change won't disturb
a git blame too much.  For future commits the pre-commit scripts
checks that this won't happen again.
2011-02-04 12:57:53 +01:00

180 lines
4.3 KiB
C

/* utils.c - Utility functions
* Copyright (C) 2009 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 <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <assert.h>
#include "g13.h"
#include "utils.h"
/* Definition of the tuple descriptor object. */
struct tupledesc_s
{
unsigned char *data; /* The tuple data. */
size_t datalen; /* The length of the data. */
size_t pos; /* The current position as used by next_tuple. */
int refcount; /* Number of references hold. */
};
/* Append the TAG and the VALUE to the MEMBUF. There is no error
checking here; this is instead done while getting the value back
from the membuf. */
void
append_tuple (membuf_t *membuf, int tag, const void *value, size_t length)
{
unsigned char buf[2];
assert (tag >= 0 && tag <= 0xffff);
assert (length <= 0xffff);
buf[0] = tag >> 8;
buf[1] = tag;
put_membuf (membuf, buf, 2);
buf[0] = length >> 8;
buf[1] = length;
put_membuf (membuf, buf, 2);
if (length)
put_membuf (membuf, value, length);
}
/* Create a tuple object by moving the ownership of (DATA,DATALEN) to
a new object. Returns 0 on success and stores the new object at
R_TUPLEHD. The return object must be released using
destroy_tuples(). */
gpg_error_t
create_tupledesc (tupledesc_t *r_desc, void *data, size_t datalen)
{
if (datalen < 5 || memcmp (data, "\x00\x00\x00\x01\x01", 5))
return gpg_error (GPG_ERR_NOT_SUPPORTED);
*r_desc = xtrymalloc (sizeof **r_desc);
if (!*r_desc)
return gpg_error_from_syserror ();
(*r_desc)->data = data;
(*r_desc)->datalen = datalen;
(*r_desc)->pos = 0;
(*r_desc)->refcount++;
return 0;
}
/* Unref a tuple descriptor and if the refcount is down to 0 release
its allocated storage. */
void
destroy_tupledesc (tupledesc_t tupledesc)
{
if (!tupledesc)
return;
if (!--tupledesc->refcount)
{
xfree (tupledesc->data);
xfree (tupledesc);
}
}
tupledesc_t
ref_tupledesc (tupledesc_t tupledesc)
{
if (tupledesc)
tupledesc->refcount++;
return tupledesc;
}
/* Find the first tuple with tag TAG. On success return a pointer to
its value and store the length of the value at R_LENGTH. If no
tuple was return NULL. For future use by next_tupe, the last
position is stored in the descriptor. */
const void *
find_tuple (tupledesc_t tupledesc, unsigned int tag, size_t *r_length)
{
const unsigned char *s;
const unsigned char *s_end; /* Points right behind the data. */
unsigned int t;
size_t n;
s = tupledesc->data;
if (!s)
return NULL;
s_end = s + tupledesc->datalen;
while (s < s_end)
{
if (s+3 >= s_end || s + 3 < s)
break;
t = s[0] << 8;
t |= s[1];
n = s[2] << 8;
n |= s[3];
s += 4;
if (s + n > s_end || s + n < s)
break;
if (t == tag)
{
tupledesc->pos = (s + n) - tupledesc->data;
*r_length = n;
return s;
}
s += n;
}
return NULL;
}
const void *
next_tuple (tupledesc_t tupledesc, unsigned int *r_tag, size_t *r_length)
{
const unsigned char *s;
const unsigned char *s_end; /* Points right behind the data. */
unsigned int t;
size_t n;
s = tupledesc->data;
if (!s)
return NULL;
s_end = s + tupledesc->datalen;
s += tupledesc->pos;
if (s < s_end
&& !(s+3 >= s_end || s + 3 < s))
{
t = s[0] << 8;
t |= s[1];
n = s[2] << 8;
n |= s[3];
s += 4;
if (!(s + n > s_end || s + n < s))
{
tupledesc->pos = (s + n) - tupledesc->data;
*r_tag = t;
*r_length = n;
return s;
}
}
return NULL;
}