| 1 |
29ea5bbf
|
henryk
|
/* Decoder Core for OpenPICC
|
| 2 |
|
|
* (C) 2006 by Harald Welte <hwelte@hmw-consulting.de>
|
| 3 |
|
|
*
|
| 4 |
|
|
* This program is free software; you can redistribute it and/or modify
|
| 5 |
|
|
* it under the terms of the GNU General Public License as published by
|
| 6 |
|
|
* the Free Software Foundation; either version 2 of the License, or
|
| 7 |
|
|
* (at your option) any later version.
|
| 8 |
|
|
*
|
| 9 |
|
|
* This program is distributed in the hope that it will be useful,
|
| 10 |
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
| 11 |
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
| 12 |
|
|
* GNU General Public License for more details.
|
| 13 |
|
|
*
|
| 14 |
|
|
* You should have received a copy of the GNU General Public License
|
| 15 |
|
|
* along with this program; if not, write to the Free Software
|
| 16 |
|
|
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
| 17 |
|
|
*
|
| 18 |
|
|
*/
|
| 19 |
|
|
|
| 20 |
|
|
#include <errno.h>
|
| 21 |
|
|
#include <sys/types.h>
|
| 22 |
|
|
|
| 23 |
|
|
#include "openpicc.h"
|
| 24 |
|
|
#include "dbgu.h"
|
| 25 |
|
|
#include "decoder.h"
|
| 26 |
|
|
|
| 27 |
|
|
static struct decoder_algo *decoder_algo[DECODER_NUM_ALGOS];
|
| 28 |
|
|
|
| 29 |
|
|
static int get_next_data(struct decoder_state *st, u_int8_t *data)
|
| 30 |
|
|
{
|
| 31 |
|
|
u_int8_t parity_sample;
|
| 32 |
|
|
u_int32_t bytesample;
|
| 33 |
|
|
|
| 34 |
|
|
bytesample = st->algo->get_next_bytesample(st, &parity_sample);
|
| 35 |
|
|
|
| 36 |
|
|
return st->algo->decode_sample(bytesample, data);
|
| 37 |
|
|
}
|
| 38 |
|
|
|
| 39 |
|
|
/* iterate over sample buffer (size N bytes) and decode data */
|
| 40 |
|
|
int decoder_decode(u_int8_t algo, const char *sample_buf,
|
| 41 |
|
|
int sample_buf_size, unsigned char *data_buf)
|
| 42 |
|
|
{
|
| 43 |
|
|
int i, ret;
|
| 44 |
|
|
struct decoder_state st;
|
| 45 |
|
|
|
| 46 |
|
|
if (algo >= DECODER_NUM_ALGOS)
|
| 47 |
|
|
return -EINVAL;
|
| 48 |
|
|
|
| 49 |
|
|
st.buf = sample_buf;
|
| 50 |
|
|
st.buf32 = (u_int32_t *) st.buf;
|
| 51 |
|
|
st.bit_ofs = 0;
|
| 52 |
|
|
st.algo = decoder_algo[algo];
|
| 53 |
|
|
|
| 54 |
|
|
for (i = 0; i < (sample_buf_size*8)/st.algo->bits_per_sampled_char;
|
| 55 |
|
|
i++) {
|
| 56 |
|
|
ret = get_next_data(&st, &data_buf[i]);
|
| 57 |
|
|
if (ret < 0) {
|
| 58 |
|
|
DEBUGPCR("decoder error %d at data byte %u",
|
| 59 |
|
|
ret, i);
|
| 60 |
|
|
return ret;
|
| 61 |
|
|
}
|
| 62 |
|
|
}
|
| 63 |
|
|
|
| 64 |
|
|
return i+1;
|
| 65 |
|
|
}
|
| 66 |
|
|
|
| 67 |
|
|
int decoder_register(int algnum, struct decoder_algo *algo)
|
| 68 |
|
|
{
|
| 69 |
|
|
if (algnum >= DECODER_NUM_ALGOS)
|
| 70 |
|
|
return -EINVAL;
|
| 71 |
|
|
|
| 72 |
|
|
decoder_algo[algnum] = algo;
|
| 73 |
|
|
|
| 74 |
|
|
return 0;
|
| 75 |
|
|
}
|
| 76 |
|
|
|
| 77 |
|
|
void decoder_init(void)
|
| 78 |
|
|
{
|
| 79 |
|
|
decoder_register(DECODER_MILLER, &miller_decoder);
|
| 80 |
|
|
decoder_register(DECODER_NRZL, &nrzl_decoder);
|
| 81 |
|
|
}
|
