tforkraw.c

/**
 * tforkraw.c gen raw sfile with native endianness based on tfork2.c
 * usage ./tforkraw outfile.raw 1.5 440 44100 0.95 0
 * (0 = 16bit | 1 = 32bit)
 * import into audacity as 16 bit/32 bit raw
 */

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

#ifndef M_PI
#define M_PI (3.141592654)
#endif

enum {
	ARG_NAME,
	ARG_OUTFILE,
	ARG_DUR,
	ARG_HZ,
	ARG_SR,
	ARG_AMP,
	ARG_TYPE,
	ARG_NARGS
};

enum samptype {
	RAWSAMP_SHORT,
	RAWSAMP_FLOAT
};

// thanks to the SNDAN programmers for this
// return 0 for big-endian machine, 1 for little-endian machine
// so we can tell user what order the data is
int byte_order()					
{						    
  int one = 1;
  char* endptr = (char *) &one;
  return (*endptr);
}

const char* endianness[2] = { "big_endian", "little_endian" };

int main(int argc, char** argv)
{
	unsigned int i,nsamps;
	unsigned int maxframe = 0;
	unsigned int samptype, endian, bitreverse;
	double samp, dur, freq, srate, amp, step;
	double start, end, fac, maxsamp;
	double twopi = 2.0 * M_PI;
	double angleincr;
	FILE* fp = NULL;
	float fsamp;
	short ssamp;

	if (argc != ARG_NARGS) {
		printf("Usage: tforkraw outsfile.raw dur freq srate amp isfloat\n");
		return 1;
	}

	dur = atof(argv[ARG_DUR]);
	freq = atof(argv[ARG_HZ]);
	srate = atof(argv[ARG_SR]);
	amp = atof(argv[ARG_AMP]);
	samptype = (unsigned int) atoi(argv[ARG_TYPE]);

	if (samptype > 1){
		printf("error: sampletype can be only 0 or 1\n");
		return 1;
	}

	// create binary file: not all systems require the 'b'
	fp = fopen(argv[ARG_OUTFILE], "wb");

	if (fp == NULL) {
		fprintf(stderr, "Error creating output file %s\n", argv[ARG_OUTFILE]);
		return 1;
	}

	nsamps = (int)(dur * srate);
	angleincr = twopi * freq / nsamps;
	step = dur / nsamps;

	// normalized range always - just scale by amp
	start = 1.0;
	end = 1.0e-4;
  maxsamp = 0.0;
	fac = pow(end / start, 1.0 / nsamps);	
	endian = byte_order();

	printf("Writing  %d %s samples\n", nsamps, endianness[endian]);

  // run the loop for this samptype
	if (samptype == RAWSAMP_SHORT) {
		for (i=0; i < nsamps; i++) {
			samp = amp * sin(angleincr * i);
			samp *= start;
			start *= fac;

      // use 32767 to avoid overflow problem
			ssamp = (short) (samp * 32767.0);

			if (fwrite(&ssamp, sizeof(short), 1, fp) != 1) {
				printf("Error writing data to file\n");
				return 1;
			}

			if (fabs(samp) > maxsamp) {
				maxsamp = fabs(samp);
				maxframe = i;
			}		
		}
	} else {
		// RAWSAMP_FLOAT
		for (i=0; i < nsamps; i++) {
			samp = amp * sin(angleincr * i);
			samp *= start;
			start *= fac;
			fsamp = (float) samp;

			if (fwrite(&fsamp, sizeof(float), 1, fp) != 1) {
				printf("Error writing data to file\n");
				return 1;
			}

			if (fabs(samp) > maxsamp) {
				maxsamp = fabs(samp);
				maxframe = i;
			}		
		}
	}
   
	fclose(fp);
	printf("done. Maximum sample value = %.8lf at frame %d\n", maxsamp, maxframe);
	return 0;
}