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//TODO: this file shouldn't be part of the GSM Receiver
#include <stdlib.h>
#include <stdio.h>
#include "interleave.h"
int
interleave_init(INTERLEAVE_CTX *ictx, int size, int block_size)
{
ictx->trans_size = size;
ictx->trans = (unsigned short *)malloc(size * sizeof *ictx->trans);
// DEBUGF("size: %d\n", size);
// DEBUGF("Block size: %d\n", block_size);
int j, k, B;
for (k = 0; k < size; k++)
{
B = k % 4;
j = 2 * ((49 * k) % 57) + ((k % 8) / 4);
ictx->trans[k] = B * block_size + j;
/* Mapping: pos1 goes to pos2: pos1 -> pos2 */
// DEBUGF("%d -> %d\n", ictx->trans[k], k);
}
// exit(0);
return 0;
}
int
interleave_init_facch_f(INTERLEAVE_CTX *ictx, int size, int block_size, int block_offset)
{
ictx->trans_size = size;
ictx->trans = (unsigned short *)malloc(size * sizeof *ictx->trans);
// DEBUGF("size: %d\n", size);
// DEBUGF("Block size: %d\n", block_size);
int j, k, B;
for (k = 0; k < size; k++)
{
B = (k + block_offset) % 8;
j = 2 * ((49 * k) % 57) + ((k % 8) / 4);
ictx->trans[k] = B * block_size + j;
/* Mapping: pos1 goes to pos2: pos1 -> pos2 */
// DEBUGF("%d -> %d\n", ictx->trans[k], k);
}
// exit(0);
return 0;
}
int
interleave_deinit(INTERLEAVE_CTX *ictx)
{
if (ictx->trans != NULL)
{
free(ictx->trans);
ictx->trans = NULL;
}
return 0;
}
void
interleave_decode(INTERLEAVE_CTX *ictx, unsigned char *dst, unsigned char *src)
{
int k;
for (k = 0; k < ictx->trans_size; k++)
dst[k] = src[ictx->trans[k]];
}
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