void decode_data(uint8_t raw[RAW_SIZE], uint8_t data[DATA_SIZE], int8_t error[2]) {
uint8_t conv[CONV_SIZE];
uint8_t dec_data[RS_SIZE];
uint8_t rs[2][RS_BLOCK_SIZE];
deinterleave(raw, conv);
viterbi(conv, dec_data);
descramble_and_deinterleave(dec_data, rs);
rs_decode(rs, data, error);
}
void decode_data_debug(
uint8_t raw[RAW_SIZE], // Data to be decoded, 5200 byte (soft bit format)
uint8_t data[DATA_SIZE], // Decoded data, 256 byte
int8_t error[2], // RS decoder modules corrected errors or -1 if unrecoverable error happened
uint8_t conv[CONV_SIZE], // Deinterleaved data with SYNC removed (5132 byte, soft bit format)
uint8_t dec_data[RS_SIZE], // Viterbi decoder output (320 byte): two RS codeblock interleaved and scrambled(!)
uint8_t rs[2][RS_BLOCK_SIZE] // RS codeblocks without the leading padding 95 zeros
) {
deinterleave(raw, conv);
viterbi(conv, dec_data);
descramble_and_deinterleave(dec_data, rs);
rs_decode(rs, data, error);
}
int librlc_rs_decode(int k, int m, int w, int packet_size,
char *available_data, int *data_list, int chunk_num,
int chunk_len, char **out_data)
{
int ret = 0;
rs_coder_t rs_code;
// rs init
rs_init(&rs_code, k+m, k, w, packet_size);
// rs decode
ret = rs_decode(rs_code.prsi, available_data, data_list, chunk_num, chunk_len, out_data);
// rs free
rs_free(&rs_code);
return ret ;
}
void test_reed_solomon()
{
//this part tests reed solomon coded_bits
unsigned int false_positives = 0, false_negatives = 0;
unsigned int tries = 10000;
unsigned int correct = 0;
unsigned int j;
for(j = 0; j < tries; j++)
{
int t = 4;
int error_count = 0;
raw_data rd;
rd.length = 64;
rd.data = (uint8_t*)alloc_named(rd.length, "main rd.data");
unsigned int i;
for(i = 0; i < rd.length; i++)
rd.data[i] = i;
raw_data encoded = rs_encode(rd, t);
uint8_t num_errors = rand() % (2 * t);
for(i = 0; i < num_errors; i++)
encoded.data[rand() % (rd.length + 2 * t)] = rand();
raw_data decoded;
uint8_t success = rs_decode(encoded, &decoded, t, &error_count);
if(memcmp(rd.data, decoded.data, rd.length) && success) //different but thinks it's right
{
false_positives++;
}
else if(!memcmp(rd.data, decoded.data, rd.length) && !success) //same but thinks it's wrong
false_negatives++;
if(!memcmp(rd.data, decoded.data, rd.length))
correct++;
dealloc(rd.data);
dealloc(encoded.data);
dealloc(decoded.data);
}
printf("false_positives = %i\n", false_positives);
printf("false_negatives = %i\n", false_negatives);
printf("out of %i tries\n", tries);
printf("percentage correct = %f\n", (float)(tries - (false_positives + false_negatives)) / (float)tries * 100.0);
printf("num_correct = %i\n", correct);
}
int rs92_ecc(int msglen) {
int i, ret = 0;
int errors;
ui8_t err_pos[rs_R], err_val[rs_R];
if (msglen > FRAME_LEN) msglen = FRAME_LEN;
for (i = msglen; i < FRAME_LEN; i++) frame[i] = 0;//xFF;
for (i = 0; i < rs_R; i++) cw[i] = frame[cfg_rs92.parpos+i];
for (i = 0; i < cfg_rs92.msglen; i++) cw[rs_R+i] = frame[cfg_rs92.msgpos+i];
errors = rs_decode(cw, err_pos, err_val);
//for (i = 0; i < cfg_rs92.hdrlen; i++) frame[i] = data[i];
for (i = 0; i < rs_R; i++) frame[cfg_rs92.parpos+i] = cw[i];
for (i = 0; i < cfg_rs92.msglen; i++) frame[cfg_rs92.msgpos+i] = cw[rs_R+i];
ret = errors;
return ret;
}
int main(int argc, char *argv[]) {
int i, len, l;
char *str = NULL, strbuf[2*BFSIZE+1];
FILE *fp = NULL;
rs = init_rs_char( 8, 0x11d, 0, 1, R, 0); // fec.c
rs_init_RS255(); // bch_ecc.c
if (argc < 2) {
fp = stdin;
str = fgets(strbuf, 2*BFSIZE, fp);
}
else {
str = argv[1];
}
while (str) {
len = strlen(str)/2;
if (len > BFSIZE) return -1;
for (i = 0; i < BFSIZE; i++) data[i] = 0;
for (i = 0; i < N; i++) codeword1[i] = codeword2[i] = 0;
for (i = 0; i < len; i++) {
l = sscanf(str+2*i, "%2hhx", data+i); if (l < 1) {/*len = i;*/}
}
cfg = detect(data, len);
if ( cfg.typ == 92 ) {
for (i = 0; i < cfg.msglen; i++) codeword1[K-1-i] = data[cfg.msgpos+i];
for (i = 0; i < R; i++) codeword1[N-1-i] = data[cfg.parpos+i];
for (i = 0; i < N; i++) cw1[i] = codeword1[N-1-i];
errors1 = decode_rs_char(rs, codeword1, errpos1, 0);
errs1 = rs_decode(cw1, err_pos1, err_val1);
if (fp == NULL) {
printf("RS%d\n", cfg.typ);
printf("codeword\n");
printf("errors: %d\n", errors1);
if (errors1 > 0) {
printf("pos: ");
for (i = 0; i < errors1; i++) printf(" %d", errpos1[i]);
printf("\n");
}
for (i = 0; i < N; i++) printf("%02X", codeword1[i]); printf("\n");
printf("frame:\n");
}
for (i = 0; i < cfg.hdrlen; i++) frame[i] = data[i];
for (i = 0; i < cfg.msglen; i++) frame[cfg.msgpos+i] = codeword1[K-1-i];
for (i = 0; i < R; i++) frame[cfg.parpos+i] = codeword1[N-1-i];
for (i = 0; i < cfg.frmlen; i++) printf("%02x", frame[i]); printf("\n");
for (i = 0; i < N; i++) {
if (cw1[i] != codeword1[N-1-i]) {
printf("diff[%3d]: cw: %02x codeword: %02x\n", i, cw1[i], codeword1[N-1-i]);
}
}
}
else
if ( cfg.typ == 41 ) {
for (i = 0; i < cfg.msglen; i++) {
codeword1[K-1-i] = data[cfg.msgpos+ 2*i];
codeword2[K-1-i] = data[cfg.msgpos+1+2*i];
}
for (i = 0; i < R; i++) {
codeword1[N-1-i] = data[cfg.parpos+ i];
codeword2[N-1-i] = data[cfg.parpos+R+i];
}
for (i = 0; i < N; i++) cw1[i] = codeword1[N-1-i];
for (i = 0; i < N; i++) cw2[i] = codeword2[N-1-i];
errors1 = decode_rs_char(rs, codeword1, errpos1, 0);
errors2 = decode_rs_char(rs, codeword2, errpos2, 0);
errs1 = rs_decode(cw1, err_pos1, err_val1);
errs2 = rs_decode(cw2, err_pos2, err_val2);
if (fp == NULL) {
printf("RS%d\n", cfg.typ);
printf("codeword1\n");
printf("errors: %d\n", errors1);
if (errors1 > 0) {
printf("pos: ");
for (i = 0; i < errors1; i++) printf(" %d", errpos1[i]);
printf("\n");
}
for (i = 0; i < N; i++) printf("%02X", codeword1[i]); printf("\n");
printf("codeword2\n");
printf("errors: %d\n", errors2);
if (errors2 > 0) {
printf("pos: ");
for (i = 0; i < errors2; i++) printf(" %d", errpos2[i]);
printf("\n");
}
for (i = 0; i < N; i++) printf("%02X", codeword2[i]); printf("\n");
printf("frame:\n");
}
for (i = 0; i < cfg.hdrlen; i++) frame[i] = data[i];
for (i = 0; i < R; i++) {
frame[cfg.parpos+ i] = codeword1[N-1-i];
frame[cfg.parpos+R+i] = codeword2[N-1-i];
}
for (i = 0; i < cfg.msglen; i++) {
frame[cfg.msgpos+ 2*i] = codeword1[K-1-i];
frame[cfg.msgpos+1+2*i] = codeword2[K-1-i];
}
for (i = 0; i < cfg.frmlen; i++) printf("%02x", frame[i]); printf("\n");
for (i = 0; i < N; i++) {
if (cw1[i] != codeword1[N-1-i]) {
printf("diff[%3d]: cw1: %02x codeword1: %02x\n", i, cw1[i], codeword1[N-1-i]);
}
}
for (i = 0; i < N; i++) {
if (cw2[i] != codeword2[N-1-i]) {
printf("diff[%3d]: cw2: %02x codeword2: %02x\n", i, cw2[i], codeword2[N-1-i]);
}
}
}
if (fp) str = fgets(strbuf, 2*BFSIZE, fp);
else str = NULL;
}
return 0;
}
int rs_decode2(int k,int n,char *data[],int size)
{
void* code=get_code(k,n);
return rs_decode(code,data,size);
}
//tests the methods used encoding and decoding, uses insert_errors2 to accomodate any bit rate
float message_pass_rate(int num_tests, float BER)
{
int successes = 0;
int errors = 0;
int tries = 0;
int wrong1 = 0, wrong2 = 0;
//for(unsigned int i = 0; i < num_tests; i++)
while(errors < 100)
{
raw_data rd;
rd.length = 64;
rd.data = (uint8_t*)alloc_named(rd.length, "message_pass_rate rd");
unsigned int i;
for(i = 0; i < 64; i++)
rd.data[i] = rand();
int t = 2; //PYTHON//
//p = make_packet(rd);
//encoded_packet ep = encode(&p); //currently convolutional- subject to change
raw_data rs_encoded = rs_encode(rd, t);
raw_data ep = convolute(rs_encoded);
interleave(ep); //interleaves data in place
insert_errors2(ep.data, ep.length, BER);
deinterleave(ep);
raw_data deconvoluted = deconvolute(ep, NULL);
int isc = is_correctible(rs_encoded, deconvoluted, t, 0);
raw_data decoded;
rs_decode(deconvoluted, &decoded, t, NULL);
//q = decode(ep, NULL);
if(rd.length != decoded.length)
{
printf("lengths are not the same!\n");
printf("rd.length = %i, decoded.length = %i\n", rd.length, decoded.length);
}
if(!memcmp(decoded.data, rd.data, rd.length))
{
if(!isc)
wrong1++;
//if(!isc)
// is_correctible(rs_encoded, deconvoluted, t, 1);
//assert(isc);
successes++;
}
else
{
if(isc)
wrong2++;
//assert(!isc);
errors++;
}
dealloc(ep.data);
dealloc(rs_encoded.data);
dealloc(deconvoluted.data);
dealloc(decoded.data);
dealloc(rd.data);
if(tries >= num_tests)
{
printf("tries = %i, errors = %i\n", tries, errors);
break;
}
tries++;
}
//return (float)successes / (float)num_tests;
printf("wrong1 = %i\n", wrong1);
printf("wrong2 = %i\n", wrong2);
printf("tests = %i\n", successes + errors);
return (float)successes / ((float)successes + (float)errors);
}
