/* dehex.c  30-Apr-89  A.J.Travis */

/* Uses __bbc__ and __riscos__ instead of DFS */

/*
 * based on Alan Philips hex to binary converter for
 * binaries in the Lancaster BBC Micro kermit distribution
 */

#include <stdio.h>

#define TRUE	1
#define FALSE	0
#define SAME	0		/* strcmp == */

#ifdef __bbc__
#define W_CAT 1				/* write MOS catalogue info */
#define RW 3				/* read/write attributes */
#endif
#ifdef __riscos__
#define W_CAT 1				/* write MOS catalogue info */
#define RW 3				/* read/write attributes */
#endif

FILE *in;
FILE *out;
int type;
int c;
char sum;
int len;
int rec;
int base;
int addr;
int q;
int i;
int verbose;			/* print details of each record extracted */

int main(argc, argv)
int argc;
char *argv[];
{
	in = NULL;
	out = NULL;
	if (argc < 3) {
		fprintf(stderr, "usage: dehex [-v] infile outfile\n");
		fatal(-1);
	}
	if (strcmp(argv[1], "-v") == SAME) {
		verbose = TRUE;
		--argc;
		++argv;
	}
	else
		verbose = FALSE;
	if ((in = fopen(argv[1], "r")) == NULL) {
		fprintf(stderr, "Input file does not exist\n");
		fatal(-1);
	}
	if ((out = fopen(argv[2], "wb")) == NULL) {
		fprintf(stderr, "Can't open output file\n");
		fatal(-1);
	}
	rec = 1;
	while (record())
		++rec;
	fclose(in);
	fclose(out);
#ifdef W_CAT
	attributes(argv[2], base, base);
#endif
	exit(0);
}



/*
 * close files, and exit on fatal error
 */
fatal(stat)
int stat;
{
	if (in)
		fclose(in);
	if (out)
		fclose(out);
	exit(stat);
}


		
/*
 * read one record
 */
record()
{
	while ((c = getc(in)) != ':') {
		if (c == EOF)
			return 0;
	}
	sum = 0;
	len = getb();
	addr = getw();
	if (rec == 1)
		base = addr;
	if ((type = getb()) == 0) {
		unhex(len);
		return 1;
	}
	else if (type == 1) {
		if (verbose)
			printf("+++ End-of-file record detected\n");
		return 0;
	}
	else {
		fprintf(stderr, "*** Unknown record type %d detected\n", type);
		fatal(-1);
	}
	if (sum != 0) {
		fprintf(stderr, "*** Checksum error (%04X)\n", sum);
		fatal(-1);
	}
}



/*
 * get hex byte from input
 */
getb()
{
	int val;
	
	val = toint(getc(in)) << 4;
	val = val + toint(getc(in));
	sum = sum + val;
	return val;
}



/*
 * get hex word from input
 */
getw()
{
	int val;
	
	val = getb() << 8;
	val = val + getb();
	return val;
}



/*
 * convert hex char to int
 */
toint(c)
int c;
{
	if (c >= 'A')
		return c - 'A' + 10;
	else
		return c - '0';
}



/*
 * extract hex record
 */
unhex(len)
int len;
{
	if (verbose)
		printf("Record %4d: Size %2d, address $%04X\n", rec, len, addr);
	addr = addr + len;
	while (len--)
		putc(getb(), out);
}



#ifdef W_CAT
/*
 * set MOS load and execution attributes on object file
 */
attributes(file, load, exec)
char *file;				/* filename to set attributes on */
unsigned load;				/* load address */
unsigned exec;				/* execution address */
{
	int *fcb[9];			/* file control block */

	fcb[0] = 0;
	fcb[1] = load;
	fcb[2] = 0;
	fcb[3] = exec;
	fcb[4] = 0;
	fcb[5] = 0;
	fcb[6] = 0;
	fcb[7] = RW;
	fcb[8] = 0;
	return(osfile(file, fcb, W_CAT));
}
#endif