/*******************************************************************
*                                                                  *
*              lrf_audio.h - Audio Port Functions Header File      *                                           *
*                                                                  *
* WRITTEN BY:  Bill Kapralos                                       *
* DATE:        Monday, June 16 1997                                *
*                                                                  *
* York University                                                  *
* Department of Computer Science                                   *
*                                                                  *
*    Part of the port initialization code (audioInit) was obtained * 
*  from soundtool.c (SUN Microsystems).                            *
*                                                                  *
*******************************************************************/

#include <stropts.h>
#include <stdio.h>
#include <sys/audioio.h>
#include <sys/file.h>
#include <sys/filio.h>
#include <sys/ioctl.h>
#include <termios.h>
#include <math.h>
#include <stdlib.h>
#include "audio_device.h"
#include "lrf_functions.h"
#include "audio_hdr.h"

#ifndef LRF_AUDIO
#define LRF_AUDIO

   #define AUDIO_PORT          "/dev/audio"     /* Audio control device name. */
   #define FREQ_SAMPLING_RATE  22050
   #define NUM_OF_SAMPLES      4000      /* Sampling Rate / readings
per sec.*/
   #define AUDIO_GAIN          40        /* Audio port volume setting.       */
   #define SAMPLE_PRECISION    16        /* Number of bits per sample.       */
   
   #define MAX_DISTANCE        15.0      /* Maximum distance reading. */
   #define MIN_DISTANCE        0.5       /* Minimum distance reading  */  
   
   #define DISTANCE_INCR       0.10      /* Distance reading accuracy.*/
   #define NUM_OF_WAVES        150       /* Number of waves cos table.*/
   
   /* The following 2 values are used two values are used in the cosine wave 
   generation equation. */  
   #define FREQ_CONST          4200 
   #define ADJUSTMENT          0.15

   static int audioFd = -1; 
   
   /* Since there is a minimum dist. defined, determine how many indeces this
      represents. */
   static int tableOffset = (int) (MIN_DISTANCE / DISTANCE_INCR);

   static int audioPortInitialized   = 0;

   /* Table holding the constant values required to eliminate the effects
      of "The Curves of Equal Loudness" for several frequencies.  This
      value allows all tones to be perceived equally loud. (as a 1000Hz
      tone). */   
   static double amplitudeTable[] = {
       1, 2238.7, 398.1, 251.2, 199.5, 100.0, 89.1, 35.5, 28.2, 25.1,
       3.5, 2.5, 1.8, 1.4, 1.3, 1.12, 1.0, 1.0, 1.0, 1.0,
       0.63, 0.3, 0.3, 0.65, 1.0, 1.3, 1.6, 1.8, 1.8
       };
   
/******************************************************/

   /* Open and initialize audio port. */
   int audioInit(char *);
   
   /* Close the audio port. */
   int audioClose();

   /* Send data to the audio port. */
   int sendAudio(short *, int);

   /* Create and initialize a table containing cosine wave samples. */
   void tableInit(short **, int);

   /* Generate a cosine wave with the frequency specified. */
   short *makeWave(double, double, int);
   
   /* Generate the depth-discontinuity signal (a pulse). */
   short *makeDepthSignal(int);
   
   /* Creates and returns a buffer representing noise when output.*/
   short *createNoise(int, double);
   
   /* Look-up & return the amplitude value corresponding to 'frequency' arg. */
   double findAmplitude(double frequency);
   
#endif