libgsmhr1 TFO: require BFI=0 and SID=0 for homing In order for a received frame to be recognized as DHF, we need not only the correct bit pattern, but also BFI=0 and SID=0. The BFI=0 requirement should be obvious, while the SID=0 requirement is needed only for HR codec. With FR and EFR, SID classification comes from the payload bits and no separate check is needed - but in HR we get an out-of-band SID ternary flag. When SID=1, no payload bits are used at all; when SID=2, we use only the first 33 bits of the payload. Therefore, it is proper to conditionalize DHF acceptance on SID=0. We already implemented this logic in the just finished full decoder; now bring TFO code into agreement.

/*
 * In this module we implement allocation and initialization
 * of state structures for our GSM 06.10 encoder & decoder
 * based on libgsm from TU-Berlin.
 */

#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include "tw_gsmfr.h"
#include "typedef.h"
#include "ed_state.h"

const unsigned gsmfr_0610_state_size = sizeof(struct gsmfr_0610_state);

struct gsmfr_0610_state *gsmfr_0610_create(void)
{
	struct gsmfr_0610_state *st;

	st = malloc(sizeof(struct gsmfr_0610_state));
	if (st)
		gsmfr_0610_reset(st);
	return st;
}

void gsmfr_0610_reset(struct gsmfr_0610_state *st)
{
	memset(st, 0, sizeof(struct gsmfr_0610_state));
	st->nrp = 40;
}