Files
simtrace2/firmware/libcommon/source/iso7816_fidi.c
Oliver Smith f721e69bc1 treewide: remove FSF address
Remove the paragraph about writing to the Free Software Foundation's
mailing address. The FSF has changed addresses in the past, and may do
so again. In 2021 this is not useful, let's rather have a bit less
boilerplate at the start of source files.

Change-Id: Ie0a3b2273383adbb3303faffd6ff96be7f4cae99
2021-12-14 11:47:21 +01:00

60 lines
1.5 KiB
C

/* ISO7816-3 Fi/Di tables + computation
*
* (C) 2010-2015 by Harald Welte <laforge@gnumonks.org>
*
* 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.
*/
#include <stdint.h>
#include <errno.h>
#include "utils.h"
#include "iso7816_fidi.h"
/* Table 7 of ISO 7816-3:2006 */
const uint16_t iso7816_3_fi_table[] = {
372, 372, 558, 744, 1116, 1488, 1860, 0,
0, 512, 768, 1024, 1536, 2048, 0, 0
};
/* Table 8 from ISO 7816-3:2006 */
const uint8_t iso7816_3_di_table[] = {
0, 1, 2, 4, 8, 16, 32, 64,
12, 20, 2, 4, 8, 16, 32, 64,
};
/* compute the F/D ratio based on Fi and Di values */
int iso7816_3_compute_fd_ratio(uint8_t f_index, uint8_t d_index)
{
uint16_t f, d;
int ret;
if (f_index >= ARRAY_SIZE(iso7816_3_fi_table) ||
d_index >= ARRAY_SIZE(iso7816_3_di_table))
return -EINVAL;
f = iso7816_3_fi_table[f_index];
if (f == 0)
return -EINVAL;
d = iso7816_3_di_table[d_index];
if (d == 0)
return -EINVAL;
/* See table 7 of ISO 7816-3: From 1000 on we divide by 1/d,
* which equals a multiplication by d */
if (d_index < 8)
ret = f / d;
else
ret = f * d;
return ret;
}