/* audio file reader 
 use Audacity to create WAV(Microsoft), Unsigned 8bit PCM files
set n (pulse stretcher loop) to match the sample rate - fine tune in Audacity

 set for LED (0) - gpio(0), the power led - this one is earthed 
- connect an amplifier to the positive end of the diode.

For each 8bit sample (0-255) this creates a plus pulse of length S
and an earth period of (255 - S) - stretched by the n value

USAGE
talk16 sound_filename  n  print_out
eg talk16 soundclip.wav 0 2 
print_out 0 - no printout
print_out 1 - prints file size and all bytes
print_out 2 - prints file size

The program opens the named wav file and counts the bytes
-it then loads this number of bytes into buffer_hi and the values (255-byte) into buffer_lo

- genuine Sunspot quality tested and approved Lesson 1 software ;-)


*/

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#include <stdio.h>
#include <sys/ioctl.h>
#include <errno.h>


int main(int argc, char** argv)
{

	int	led_fd 			= 0;
	int		f_status 	= 1;
	int		i;
	int		j;
	int led_nr = 0;
	int ontime; 
	int offtime;
	int samples; /*number of bytes to be read from the file*/
	int count; /* this counts up to value of samples*/
	int k; /* for the delay loops - usleep has a minimum delay! */
	int n ;/*use for delay loop to stretch the pulse lengths*/
	int print_out;

 if (argc != 4)
 {
  printf("Error. usage: %s file_to_read.wav stretcher_count print_out\n", argv[0]);
  f_status = 0;             
 }

/* name of file to open goes int argv[1]- eg soundclip.wav */
/* set the pulse stretcher count*/
	n = atoi(argv[2]);
/* set 1 for printout, 0 for none*/
	print_out = atoi(argv[3]);
// hold the sound samples in memory


//-------------------------------fill the buffer array from the sound samples file

FILE *fp = fopen( argv[1], "rb");//open to read as binary

	if (fp == NULL) 
		{
		printf("The file didn't open.\n");
		return 0;
		}

//	get input file length
	fseek(fp,0,SEEK_END);
	samples = ftell(fp);
			if (print_out == 2)
			{
			printf("total number of samples = ");
			printf("%d",samples);
			printf("\n\n");
			}
// now we know the size of the file so set up the 2 arrays
samples = samples - 4;//hey! 4  works, zero does not!

//set up the arrays to hold the sound amplitude values for fast output
int buffer_lo[samples];
int buffer_hi[samples];


// set for first read from the wav file
	fseek(fp,0,SEEK_SET);

	for (i=0; i < samples; i++) 

		{
        	int c = fgetc(fp);
        	if (c == EOF) 
			{
            		printf("There was an error reading the file.\n");
            		break;
			}
		buffer_hi[i] = c; //use for the plus pulse time
		buffer_lo[i] = 255 - c; //use for the base line time

			if (print_out == 1)
			{
			printf("%d",i);
			printf("-->");
			printf("%d",buffer_hi[i]);
			printf("+");
			printf("%d",buffer_lo[i]);
			printf("\n");
			}
		}
 fclose(fp);

samples = samples - 4;
//-------------------------------------------------------------
// fast loop follows - error detection and led number variable removed for speed
// two buffer arrays used for symmetry of delays
// perhaps remove delay stretcher and increase sample rate?

led_fd = open("/dev/gpio0",O_RDWR);

for (count = 1;count <= samples;count = count + 1)
  {
            /* positive pulse time*/
            ioctl(led_fd, 0, 0);
		for (k = 1;k <= buffer_hi[count];k = k + 1)
		{
		 	for (j = 0;j <= n;j = j + 1)
			{
			/*delay stretcher*/
			}
		}

            /* zero volts time */
            ioctl(led_fd, 1, 0);
		for (k = 1;k <= buffer_lo[count];k = k + 1)
		{
			for (j = 0;j <= n;j = j + 1)
			{
			/*delay stretcher*/
			}
		}
   }
close (led_fd);
//is that close OK?----------------------------------------------------------
	return 0;
}