void BCH::initialize(int _m, int _length, int _t)
{
int i;
m = _m;
length = _length;
t = _t;
p.resize(BCH_MAX_P);
alpha_to.resize(BCH_MAX_LUT);
index_of.resize(BCH_MAX_LUT);
g.resize(BCH_MAX_LUT);
_elp.resize(BCH_MAX_LUT);
for(i=0; i<BCH_MAX_LUT; i++) _elp[i].resize(BCH_MAX_LUT);
_d.resize(BCH_MAX_LUT);
_l.resize(BCH_MAX_LUT);
_u_lu.resize(BCH_MAX_LUT);
_s.resize(BCH_MAX_LUT);
_root.resize(BCH_MAX_LUT);
_loc.resize(BCH_MAX_LUT);
_reg.resize(BCH_MAX_LUT);
for (i=1; i<m; i++)
p[i] = 0;
p[0] = p[m] = 1;
if (m == 2) p[1] = 1;
else if (m == 3) p[1] = 1;
else if (m == 4) p[1] = 1;
else if (m == 5) p[2] = 1;
else if (m == 6) p[1] = 1;
else if (m == 7) p[1] = 1;
else if (m == 8) p[4] = p[5] = p[6] = 1;
else if (m == 9) p[4] = 1;
else if (m == 10) p[3] = 1;
else if (m == 11) p[2] = 1;
else if (m == 12) p[3] = p[4] = p[7] = 1;
else if (m == 13) p[1] = p[3] = p[4] = 1;
else if (m == 14) p[1] = p[11] = p[12] = 1;
else if (m == 15) p[1] = 1;
else if (m == 16) p[2] = p[3] = p[5] = 1;
else if (m == 17) p[3] = 1;
else if (m == 18) p[7] = 1;
else if (m == 19) p[1] = p[5] = p[6] = 1;
else if (m == 20) p[3] = 1;
n = 1;
for (i = 0; i <= m; i++)
{
n *= 2;
}
n = n / 2 - 1;
generate_gf(); /* Construct the Galois Field GF(2**m) */
gen_poly(t); /* Compute the generator polynomial of BCH code */
}
main()
{
int i;
generate_gf(); /* generate the Galois Field GF(2**m) 算伽罗伐域各个元素 */
gen_poly(); /* Compute the generator polynomial of BCH code 计算生成多项式 */
for (i = 0; i < REDUNDANCYSIZE+1; i++) {
printf("%d, ", g[i]);
if (i && ((i % 64) == 0))
printf("\n");
}
printf("\n");
getchar();
system("pause");
}
main()
{
int i;
read_p(); /* Read m */
generate_gf(); /* Construct the Galois Field GF(2**m) */
gen_poly(); /* Compute the generator polynomial of BCH code */
/* Randomly generate DATA */
seed = 131073;
srandom(seed);
for (i = 0; i < k; i++)
data[i] = ( random() & 65536 ) >> 16;
encode_bch(); /* encode data */
/*
* recd[] are the coefficients of c(x) = x**(length-k)*data(x) + b(x)
*/
for (i = 0; i < length - k; i++)
recd[i] = bb[i];
for (i = 0; i < k; i++)
recd[i + length - k] = data[i];
printf("Code polynomial:\nc(x) = ");
for (i = 0; i < length; i++) {
printf("%1d", recd[i]);
if (i && ((i % 50) == 0))
printf("\n");
}
printf("\n");
printf("Enter the number of errors:\n");
scanf("%d", &numerr); /* CHANNEL errors */
printf("Enter error locations (integers between");
printf(" 0 and %d): ", length-1);
/*
* recd[] are the coefficients of r(x) = c(x) + e(x)
*/
for (i = 0; i < numerr; i++)
scanf("%d", &errpos[i]);
if (numerr)
for (i = 0; i < numerr; i++)
recd[errpos[i]] ^= 1;
printf("r(x) = ");
for (i = 0; i < length; i++) {
printf("%1d", recd[i]);
if (i && ((i % 50) == 0))
printf("\n");
}
printf("\n");
decode_bch(); /* DECODE received codeword recv[] */
/*
* print out original and decoded data
*/
printf("Results:\n");
printf("original data = ");
for (i = 0; i < k; i++) {
printf("%1d", data[i]);
if (i && ((i % 50) == 0))
printf("\n");
}
printf("\nrecovered data = ");
for (i = length - k; i < length; i++) {
printf("%1d", recd[i]);
if ((i-length+k) && (((i-length+k) % 50) == 0))
printf("\n");
}
printf("\n");
/*
* DECODING ERRORS? we compare only the data portion
*/
for (i = length - k; i < length; i++)
if (data[i - length + k] != recd[i])
decerror++;
if (decerror)
printf("There were %d decoding errors in message positions\n", decerror);
else
printf("Succesful decoding\n");
}
