/* Burrows-Wheeler transform. */
saint_t
bw_transform(const sauchar_t *T, sauchar_t *U, saidx_t *SA,
saidx_t n, saidx_t *idx) {
saidx_t *A, i, j, p, t;
saint_t c;
/* Check arguments. */
if((T == NULL) || (U == NULL) || (n < 0) || (idx == NULL)) { return -1; }
if(n <= 1) {
if(n == 1) { U[0] = T[0]; }
*idx = n;
return 0;
}
if((A = SA) == NULL) {
i = divbwt(T, U, NULL, n);
if(0 <= i) { *idx = i; i = 0; }
return (saint_t)i;
}
/* BW transform. */
if(T == U) {
t = n;
for(i = 0, j = 0; i < n; ++i) {
p = t - 1;
t = A[i];
if(0 <= p) {
c = T[j];
U[j] = (j <= p) ? T[p] : (sauchar_t)A[p];
A[j] = c;
j++;
} else {
*idx = i;
}
}
p = t - 1;
if(0 <= p) {
c = T[j];
U[j] = (j <= p) ? T[p] : (sauchar_t)A[p];
A[j] = c;
} else {
*idx = i;
}
} else {
U[0] = T[n - 1];
for(i = 0; A[i] != 0; ++i) { U[i + 1] = T[A[i] - 1]; }
*idx = i + 1;
for(++i; i < n; ++i) { U[i] = T[A[i] - 1]; }
}
if(SA == NULL) {
/* Deallocate memory. */
free(A);
}
return 0;
}
int bsc_bwt_encode(unsigned char * T, int n, unsigned char * num_indexes, int * indexes, int features)
{
int index = divbwt(T, T, NULL, n, num_indexes, indexes, features & LIBBSC_FEATURE_MULTITHREADING);
switch (index)
{
case -1 : return LIBBSC_BAD_PARAMETER;
case -2 : return LIBBSC_NOT_ENOUGH_MEMORY;
}
return index;
}
