source: roaraudio/roarclients/roarsin.c

//roarsin.c:

/*
 *      Copyright (C) Philipp 'ph3-der-loewe' Schafft - 2008-2015
 *
 *  This file is part of roarclients a part of RoarAudio,
 *  a cross-platform sound system for both, home and professional use.
 *  See README for details.
 *
 *  This file is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 3
 *  as published by the Free Software Foundation.
 *
 *  RoarAudio 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 software; see the file COPYING.  If not, write to
 *  the Free Software Foundation, 51 Franklin Street, Fifth Floor,
 *  Boston, MA 02110-1301, USA.
 *
 */

#include <roaraudio.h>  /* libroar */

#ifdef ROAR_HAVE_LIBM

#include <math.h>       /* sin() */
#include <stdio.h>      /* *printf*() */

double rect (double x) {
 x /= 2*M_PI;
 x -= (int)x;

 if ( x < 0.5 )
  return  1;
 else
  return -1;
}

double saw (double x) {
 x /= 2*M_PI;
 x -= (int)x;

 return 2*x - 1;
}

double tri (double x) {
 x /= 2*M_PI;
 x -= (int)x;

 if ( x < 0.5 )
  return   4* x      - 1;
 else
  return  -4*(x-0.5) + 1;
}

double trap (double x) {
 x /= 2*M_PI;
 x -= (int)x;

 if ( x < 0.125 || x > 0.875 ) {
  return -1;
 } else if ( x < 0.625 && x > 0.375 ) {
  return  1;
 } else if ( x < 0.5 ) {
  return  8*(x-0.375) + 1;
 } else {
  return -8*(x-0.625) + 1;
 }
}

static void usage(const char * progname) {
 fprintf(stderr, "Usage: %s [OPTIONS] [FUNCTION]\n", progname);

 fprintf(stderr, "\nOptions:\n\n");
 fprintf(stderr,
         "  --help                  - Show this help\n"
         "  --server SERVER         - Set server address\n"
         "  --rate   -R  RATE       - Set sample rate to use\n"
         "  --freq FREQ             - Set frequency (in Hz)\n"
         "  --time TIME             - Set time (in sec)\n"
         "  --volume VOL            - Set volume\n"
        );

 fprintf(stderr, "\nFunctions:\n\n");
 fprintf(stderr,
         "  --sin                   - Use Sinus\n"
         "  --rect                  - Use Rectangle\n"
         "  --saw                   - Use Saw\n"
         "  --tri                   - Use Triangle\n"
         "  --trap                  - Use Trap\n"
        );
}

int main (int argc, char * argv[]) {
 const char * k;
 const char * server = NULL;
 int rate     = ROAR_RATE_DEFAULT;
 float freq   = 523.2;            /* middle C */
 float t      = 0; /* current time */
 float tcalc  = 0; /* current time for calculation */
 float length = 5; /* 5 sec */
 float step;       /* how much time per sample we have to encode ... */
 roar_vs_t * vss;
 int err;
 int i;
 int16_t out[1024];
 double (*func)(double x) = sin;
 double volume = 1;

 for (i = 1; i < argc; i++) {
  k = argv[i];
  if ( !strcmp(k, "--freq") ) {
   ROAR_CKHAVEARGS(1);
   freq   = atof(argv[++i]);
  } else if ( !strcmp(k, "--time") ) {
   ROAR_CKHAVEARGS(1);
   length = atof(argv[++i]);
  } else if ( !strcmp(k, "--server") ) {
   ROAR_CKHAVEARGS(1);
   server = argv[++i];
  } else if ( !strcmp(k, "--rate") || !strcmp(k, "-R") ) {
   ROAR_CKHAVEARGS(1);
   rate = roar_str2rate(argv[++i]);
  } else if ( !strcmp(k, "--volume") ) {
   ROAR_CKHAVEARGS(1);
   volume = atof(argv[++i]);
  } else if ( !strcmp(k, "--sin") ) {
   func   = sin;
  } else if ( !strcmp(k, "--rect") ) {
   func   = rect;
  } else if ( !strcmp(k, "--saw") ) {
   func   = saw;
  } else if ( !strcmp(k, "--tri") ) {
   func   = tri;
  } else if ( !strcmp(k, "--trap") ) {
   func   = trap;
  } else if ( !strcmp(k, "--help") ) {
   usage(argv[0]);
   return 0;
  } else {
   usage(argv[0]);
   return 2;
  }
 }

 step   = M_PI*2*freq/rate;

 if ( (vss = roar_vs_new_playback(server, "sine gen", rate, 1, ROAR_CODEC_DEFAULT, 16, &err)) == NULL ) {
  fprintf(stderr, "Error: can not open playback: %s\n", roar_vs_strerr(err));
  exit(1);
 }

 if ( roar_vs_volume_mono(vss, volume, NULL) == 0 ) {
  // If setting server volume successed set local volume to one.
  volume = 1;
 }

 while (t < 2*M_PI*freq*length) {
  for (i = 0; i < 1024; i++) {
   out[i] = 32767.*volume*func(tcalc);
   t     += step;
   tcalc += step;
  }
  if ( roar_vs_write(vss, out, 2048, &err) != (ssize_t)2048 ) {
   fprintf(stderr, "Error: can not write data: %s\n", roar_vs_strerr(err));
   break;
  }

  // this code enables us to generate the same signal for a long periode of time
  // without loosing accuracy of the float type.
  while (tcalc > 2*M_PI)
   tcalc -= 2*M_PI;
 }

 roar_vs_close(vss, ROAR_VS_FALSE, NULL);

 return 0;
}

#else
int main (void) {
 fprintf(stderr, "Error: No Math library support compiled in.\n");
 return 1;
}
#endif

//ll