tonegen.c

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/* $Id: tonegen.c 1010 2007-02-27 00:13:47Z bennylp $ */
/* 
 * Copyright (C) 2003-2007 Benny Prijono <[e-mail]>
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 
 */
#include <pjmedia/tonegen.h>
#include <pjmedia/errno.h>
#include <pj/assert.h>
#include <pj/ctype.h>
#include <pj/pool.h>


/* float can be twice slower on i686! */
#define DATA	double

/* amplitude */
#define AMP	8192


#ifndef M_PI
#   define M_PI  ((DATA)3.141592653589793238462643383279)
#endif


#if defined(PJ_HAS_FLOATING_POINT) && PJ_HAS_FLOATING_POINT!=0
    /*
     * Default floating-point based tone generation using sine wave 
     * generation from:
     *   http://www.musicdsp.org/showone.php?id=10.
     * This produces good quality tone in relatively faster time than
     * the normal sin() generator.
     * Speed = 40.6 cycles per sample.
     */
#   include <math.h>
    struct gen
    {
	DATA a, s0, s1;
    };

#   define GEN_INIT(var,R,F,A)	 var.a = (DATA) (2.0 * sin(M_PI * F / R)); \
				 var.s0 = A; \
				 var.s1 = 0
#   define GEN_SAMP(val,var)	 var.s0 = var.s0 - var.a * var.s1; \
				 var.s1 = var.s1 + var.a * var.s0; \
				 val = (short) var.s0


#elif !defined(PJ_HAS_FLOATING_POINT) || PJ_HAS_FLOATING_POINT==0
    /* 
     * Fallback algorithm when floating point is disabled.
     * This is a very fast fixed point tone generation using sine wave
     * approximation from
     *    http://www.audiomulch.com/~rossb/code/sinusoids/ 
     * Quality wise not so good, but it's blazing fast!
     * Speed: 
     *	- with volume adjustment: 14 cycles per sample 
     *  - without volume adjustment: 12.22 cycles per sample
     */
    PJ_INLINE(int) approximate_sin3(unsigned x)
    {	
	    unsigned s=-(int)(x>>31);
	    x+=x;
	    x=x>>16;
	    x*=x^0xffff;            // x=x*(2-x)
	    x+=x;                   // optional
	    return x^s;
    }
    struct gen
    {
	unsigned add;
	unsigned c;
	unsigned vol;
    };

#   define MAXI			((unsigned)0xFFFFFFFF)
#   define SIN			approximate_sin3
#   if 1    /* set this to 0 to disable volume adjustment */
#	define VOL(var,v)	(((v) * var.vol) >> 16)
#   else
#	define VOL(var,v)	(v)
#   endif
#   define GEN_INIT(var,R,F,A)	var.add = MAXI/R * F, var.c=0, var.vol=A
#   define GEN_SAMP(val,var)	val = (short) VOL(var,SIN(var.c)>>16);\
				var.c += var.add


#else
#   error "Should never get to this part"
#   include <math.h>
    /*
     * Should never really reach here, but anyway it's provided for reference.
     * This is the good old tone generator using sin().
     * Speed = 222.5 cycles per sample.
     */
    struct gen
    {
	DATA add;
	DATA c;
	DATA vol;
    };

#   define GEN_INIT(var,R,F,A) var.add = ((DATA)F)/R, var.c=0, var.vol=A
#   define GEN_SAMP(val,var)   val = (short)(sin(var.c * 2 * M_PI) * var.vol);\
			       var.c += var.add

#endif

struct gen_state
{
    struct gen tone1;
    struct gen tone2;
    pj_bool_t  has_tone2;
};


static void init_generate_single_tone(struct gen_state *state,
				      unsigned clock_rate, 
				      unsigned freq,
				      unsigned vol)
{
    GEN_INIT(state->tone1,clock_rate,freq,vol);
    state->has_tone2 = PJ_FALSE;
}

static void generate_single_tone(struct gen_state *state,
				 unsigned channel_count,
				 unsigned samples,
				 short buf[]) 
{
    short *end = buf + samples;

    if (channel_count==1) {

	while (buf < end) {
	    GEN_SAMP(*buf++, state->tone1);
	}

    } else if (channel_count == 2) {

	while (buf < end) {
	    GEN_SAMP(*buf, state->tone1);
	    *(buf+1) = *buf;
	    buf += 2;
	}
    }
}


static void init_generate_dual_tone(struct gen_state *state,
				    unsigned clock_rate, 
				    unsigned freq1,
				    unsigned freq2,
				    unsigned vol)
{
    GEN_INIT(state->tone1,clock_rate,freq1,vol);
    GEN_INIT(state->tone2,clock_rate,freq2,vol);
    state->has_tone2 = PJ_TRUE;
}


static void generate_dual_tone(struct gen_state *state,
			       unsigned channel_count,
			       unsigned samples,
			       short buf[]) 
{
    short *end = buf + samples;

    if (channel_count==1) {
	int val, val2;
	while (buf < end) {
	    GEN_SAMP(val, state->tone1);
	    GEN_SAMP(val2, state->tone2);
	    *buf++ = (short)((val+val2) >> 1);
	}
    } else if (channel_count == 2) {
	int val, val2;
	while (buf < end) {

	    GEN_SAMP(val, state->tone1);
	    GEN_SAMP(val2, state->tone2);
	    val = (val + val2) >> 1;

	    *buf++ = (short)val;
	    *buf++ = (short)val;
	}
    }
}


static void init_generate_tone(struct gen_state *state,
			       unsigned clock_rate, 
			       unsigned freq1,
			       unsigned freq2,
			       unsigned vol)
{
    if (freq2)
	init_generate_dual_tone(state, clock_rate, freq1, freq2 ,vol);
    else
	init_generate_single_tone(state, clock_rate, freq1,vol);
}


static void generate_tone(struct gen_state *state,
			  unsigned channel_count,
			  unsigned samples,
			  short buf[])
{
    if (!state->has_tone2)
	generate_single_tone(state, channel_count, samples, buf);
    else
	generate_dual_tone(state, channel_count, samples, buf);
}


/****************************************************************************/

#define SIGNATURE   PJMEDIA_PORT_SIGNATURE('t', 'n', 'g', 'n')

struct tonegen
{
    pjmedia_port	base;

    /* options */
    unsigned		options;
    unsigned		playback_options;

    /* Digit map */
    pjmedia_tone_digit_map  *digit_map;

    /* Tone generation state */
    struct gen_state	state;

    /* Currently played digits: */
    unsigned		count;		    /* # of digits		*/
    unsigned		cur_digit;	    /* currently played		*/
    unsigned		dig_samples;	    /* sample pos in cur digit	*/
    pjmedia_tone_desc	digits[PJMEDIA_TONEGEN_MAX_DIGITS];/* array of digits*/
};


/* Default digit map is DTMF */
static pjmedia_tone_digit_map digit_map = 
{
    16,
    {
	{ '0', 941,  1336 },
	{ '1', 697,  1209 },
	{ '2', 697,  1336 },
	{ '3', 697,  1447 },
	{ '4', 770,  1209 },
	{ '5', 770,  1336 },
	{ '6', 770,  1447 },
	{ '7', 852,  1209 },
	{ '8', 852,  1336 },
	{ '9', 852,  1447 },
	{ 'a', 697,  1633 },
	{ 'b', 770,  1633 },
	{ 'c', 852,  1633 },
	{ 'd', 941,  1633 },
	{ '*', 941,  1209 },
	{ '#', 941,  1477 },
    }
};


static pj_status_t tonegen_get_frame(pjmedia_port *this_port, 
				     pjmedia_frame *frame);

/*
 * Create an instance of tone generator with the specified parameters.
 * When the tone generator is first created, it will be loaded with the
 * default digit map.
 */
PJ_DEF(pj_status_t) pjmedia_tonegen_create2(pj_pool_t *pool,
					    const pj_str_t *name,
					    unsigned clock_rate,
					    unsigned channel_count,
					    unsigned samples_per_frame,
					    unsigned bits_per_sample,
					    unsigned options,
					    pjmedia_port **p_port)
{
    const pj_str_t STR_TONE_GEN = pj_str("tone-gen");
    struct tonegen  *tonegen;
    pj_status_t status;

    PJ_ASSERT_RETURN(pool && clock_rate && channel_count && 
		     samples_per_frame && bits_per_sample == 16 && 
		     p_port != NULL, PJ_EINVAL);

    /* Only support mono and stereo */
    PJ_ASSERT_RETURN(channel_count==1 || channel_count==2, PJ_EINVAL);

    /* Create and initialize port */
    tonegen = pj_pool_zalloc(pool, sizeof(struct tonegen));
    if (name == NULL || name->slen == 0) name = &STR_TONE_GEN;