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/*
* gen_dtmf.c -- generate DTMF sequences
*
* Copyright (C) 1997
* Thomas Sailer (sailer@ife.ee.ethz.ch, hb9jnx@hb9w.che.eu)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/* ---------------------------------------------------------------------- */
#include "gen.h"
#include <string.h>
#include <ctype.h>
#include <stdio.h>
/* ---------------------------------------------------------------------- */
/*
*
* DTMF frequencies
*
* 1209 1336 1477 1633
* 697 1 2 3 A
* 770 4 5 6 B
* 852 7 8 9 C
* 941 * 0 # D
*
*/
static const char *dtmf_transl = "123A456B789C*0#D";
#define PHINC(x) ((float)(x)*0x10000/SAMPLE_RATE)
static const unsigned int row_freq[4] = {
PHINC(697), PHINC(770), PHINC(852), PHINC(941)
};
static const unsigned int col_freq[4] = {
PHINC(1209), PHINC(1336), PHINC(1477), PHINC(1633)
};
void gen_init_dtmf(struct gen_params *p, struct gen_state *s)
{
memset(s, 0, sizeof(struct gen_state));
}
int gen_dtmf(signed short *buf, int buflen, struct gen_params *p, struct gen_state *s)
{
char c;
char *cp;
int num = 0, i;
for (; buflen > 0; buflen--, buf++, num++) {
if (s->s.dtmf.time <= 0) {
c = p->p.dtmf.str[s->s.dtmf.ch_idx];
if (!c)
return num;
s->s.dtmf.ch_idx++;
cp = memchr(dtmf_transl, toupper(c), 16);
if (!cp) {
s->s.dtmf.time = s->s.dtmf.time2 = 1;
fprintf(stderr, "gen: dtmf; invalid char '%c'\n", c);
} else {
s->s.dtmf.time = p->p.dtmf.duration + p->p.dtmf.pause;
s->s.dtmf.time2 = p->p.dtmf.duration;
i = cp - dtmf_transl;
s->s.dtmf.phinc_row = row_freq[(i >> 2) & 3];
s->s.dtmf.phinc_col = col_freq[i & 3];
}
} else if (!s->s.dtmf.time2) {
s->s.dtmf.phinc_row = s->s.dtmf.phinc_col = 0;
s->s.dtmf.ph_row = s->s.dtmf.ph_col = 0xc000;
}
s->s.dtmf.time--;
s->s.dtmf.time2--;
*buf += ((p->ampl >> 1) * (COS(s->s.dtmf.ph_row) + COS(s->s.dtmf.ph_col))) >> 15;
s->s.dtmf.ph_row += s->s.dtmf.phinc_row;
s->s.dtmf.ph_col += s->s.dtmf.phinc_col;
}
return num;
}
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