/*
	gftopbm.c -- gf -> pbm conversion
*/

#include "defs.h"

#define DEBUG 0
#if DEBUG
#define D(x) x
#else
#define D(x)
#endif


#define IMGSIZE 	32767
#define MAXL_NAME	64
#define ERRGLYPH	-2

int main(int argc, char **argv);
void usage(void);
int preamble(void);
int glyph(void);
long geti4(unsigned char *);
void paint(unsigned *, unsigned *, unsigned *, unsigned);
int skipfile(long);
int outpbm(char *);


char *inname;
unsigned char image[IMGSIZE];
char bname[MAXL_NAME];
FILE *infile;
unsigned int code, width, height, hbytes;


int
main(int argc, char **argv) {
	int code;
	char *p, *q;
	int mincode = 0, maxcode = 255;
	
	for (argc--, argv++; argc; argc--, argv++) {
		p = *argv;
		if (*p == '-') {
			p = *argv + 1;
			mincode = (int)strtol(p, &p, 0);
			if (*p == '-') {
				p++;
				maxcode = (int)strtol(p, &p, 0);
			}
			else  maxcode = mincode;
		}
		else  inname = p;
	}
	if (*inname == 0)  usage();
	strcpy(bname, inname);
	p = strrchr(bname, '\\');	/*  skip directory name  */
	if (p)  p++;
	else  p = bname;
	q = strchr(p, '.');				/*  remove extension  */
	if (q) {
		if (q - p > 6)  q = p + 6;	/*  short name  */
		*q = 0;
	}
	else  q = strchr(p, 0);		/*  tail  */
	
	if (0 == (infile = fopen(inname, "rb"))) {
		fprintf(stderr, "Can't open %s\n", inname);
		exit(1);
	}
	if (preamble() == ERROR) {
		errmsg("Not a gf file\n");
		exit(1);
	}
	while (0 <= (code = glyph())) {
		if (code == ERRGLYPH) {
			errmsg("Error in glyph section\n");
			exit(1);
		}
		if (code >= mincode && code <= maxcode) {
			sprintf(q, "%02X.pbm", code);
			if (ERROR == outpbm(p)) {
				fprintf(stderr, "Can' to write to %s\n", bname);
				exit(1);
			}
		}
	} /* while */
	return 0;
} /* main */


void
usage() {
	errmsg("Usage: gftopbm [-mincode[-maxcode]] infile\n");
	exit(1);
}


int
preamble() {
	unsigned char buf[3];
	int n;
	
	if (3 > fread(buf, 1, 3, infile))  return ERROR;
	if (buf[0] != 247 || buf[1] != 131)  return ERROR;
	n = buf[2];
	if (n > fread(image, 1, n, infile))  return ERROR;
	fprintf(stderr, "comment='%s'\n", image);
	return OK;
}


int
glyph() {
	int i;
	unsigned char buf[24];
	long min_m, max_m, min_n, max_n;
	long count;
	unsigned sw, m, n;
	
	if (EOF == (i = fgetc(infile)))  return ERRGLYPH;
	if (i == 67) {			/* boc */
		if (24 > fread(buf, 1, 24, infile))  return ERRGLYPH;
		code = (unsigned)geti4(buf);
		min_m = geti4(buf + 8);
		max_m = geti4(buf + 12);
		min_n = geti4(buf + 16);
		max_n = geti4(buf + 20);
		width = max_m - min_m;
		height = max_n - min_n + 1;
	}
	else if (i == 68) {		/* boc1 */
		if (5 > fread(buf, 1, 5, infile))  return ERRGLYPH;
		code = buf[0];
		width = buf[1];
		height = buf[3] + 1;
	}
	else if (i == 248) {	/* post */
		return EOF;
	}
	else return ERRGLYPH;
	
	fprintf(stderr, "code=%u, width=%u, height=%u\n", code, width, height);
	hbytes = (width + 7) / 8;
	
	memset(image, 0, IMGSIZE);
	sw = m = n = 0;
	while (0 <= (i = fgetc(infile))) {
		D(fprintf(stderr, "inst=%d ", i);)
		if (i >= 0 && i <= 63) {	/* paint_0 - 63 */
			paint(&m, &n, &sw, i);
		}
		else if (i >= 74 && i <= 238) {		/* new_row */
			m = i - 74;
			n++;
			sw = 1;
			D(fprintf(stderr, "(%u,%u)\n", m, n);)
		}
		else switch (i) {
		case 64:	/* paint1 */
			if (EOF == (i = fgetc(infile)))  return ERRGLYPH;
			paint(&m, &n, &sw, (unsigned)i);
			break;
		case 65:	/* paint2 */
			if (2 > fread(buf, 1, 2, infile))  return ERRGLYPH;
			count = buf[0] * 0x100L + buf[1];
			paint(&m, &n, &sw, (unsigned)count);
			break;
		case 66:	/* paint3 */
			if (3 > fread(buf, 1, 3, infile))  return ERRGLYPH;
			count = buf[0] * 0x10000L + buf[1] * 0x100L + buf[2];
			paint(&m, &n, &sw, (unsigned)count);
			break;
		case 69:	/* eoc */
			return code;
			break;
		case 70:	/* skip0 */
			m = 0;  n++;  sw = 0;
			break;
		case 71:	/* skip1 */
			if (EOF == (i = fgetc(infile)))  return ERRGLYPH;
			m = 0;  n += i + 1;  sw = 0;
			break;
		case 72:	/* skip2 */
			if (2 > fread(buf, 1, 2, infile))  return ERRGLYPH;
			count = buf[0] * 0x100L + buf[1];
			m = 0;  n += count + 1;  sw = 0;
			break;
		case 73:	/* skip3 */
			if (3 > fread(buf, 1, 3, infile))  return ERRGLYPH;
			count = buf[0] * 0x10000L + buf[1] * 0x100L + buf[2];
			m = 0;  n += count + 1;  sw = 0;
			break;
		case 239:	/* xxx1 */
			if (EOF == (i = fgetc(infile)))  return ERRGLYPH;
			if (ERROR == skipfile(i))  return ERRGLYPH;
			break;
		case 240:	/* xxx2 */
			if (2 > fread(buf, 1, 2, infile))  return ERRGLYPH;
			count = buf[0] * 0x100 + buf[1];
			if (ERROR == skipfile(count))  return ERRGLYPH;
			break;
		case 241:	/* xxx3 */
			if (3 > fread(buf, 1, 3, infile))  return ERRGLYPH;
			count = buf[0] * 0x10000L + buf[1] * 0x100L + buf[2];
			if (ERROR == skipfile(count))  return ERRGLYPH;
			break;
		case 242:	/* xxx4 */
			if (4 > fread(buf, 1, 4, infile))  return ERRGLYPH;
			count = geti4(buf);
			if (ERROR == skipfile(count))  return ERRGLYPH;
			break;
		case 244:	/* no_op */
			break;
		default:
			return ERRGLYPH;
		}
	} /* while */
	return ERRGLYPH;
}


long
geti4(unsigned char *ptr) {
	long n;
#if LITTLE_ENDIAN
	unsigned char *np = (unsigned char *)&n;
	np[0] = ptr[3];
	np[1] = ptr[2];
	np[2] = ptr[1];
	np[3] = ptr[0];
#else
	n = *(long *)ptr;
#endif
	return n;
}


void
paint(unsigned *m, unsigned *n, unsigned *sw, unsigned i) {
	unsigned char *ptr;
	int bit;
	static unsigned char mask[] = 
		{ 0x80, 0x40, 0x20, 0x10, 0x08, 0x04, 0x02, 0x01 };
	
	D(fprintf(stderr, "(%u,%u)+%u(%s)\n", *m, *n, i, (*sw ? "on" : "off"));)
	ptr = image + *n * hbytes + *m / 8;
	bit = *m % 8;
	*m += i;
	if (*sw) {
		while (i--) {
			*ptr |= mask[bit];
			if (++bit > 7) {
				bit = 0;  ptr++;
			}
		}
	}
	*sw = !*sw;
}


int
skipfile(long i) {
	while (i-- > 0) {
		if (EOF == fgetc(infile))  return EOF;
	}
	return OK;
}


int
outpbm(char *outname) {
	FILE *outfile;
	long nbyte;
	
	fprintf(stderr, "Writing into %s\n", outname);
	if (NULL == (outfile = fopen(outname, "wb")))  return ERROR;
	fprintf(outfile, "P4\n%u %u\n", width, height);
	nbyte = (((long)width + 7) / 8) * (long)height;
	if (nbyte > fwrite(image, 1, (size_t)nbyte, outfile))  return ERROR;
	fclose(outfile);
	return OK;
}