/*
 * ihxtobin, converts Intel hex format to binary
 * Copyright 2002, 2004 Chris Williams <cow3.14@juno.com>
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

/* I wrote this a couple years ago, so there are probably
 * some beginner's mistakes in here. :-/ Just FYI.
 */

/* FIXME: This programs takes no arguments like for infile, outfile, or
 * even to display help or program version. Add them, please.
 */

#include <stdio.h>

#define STRINGIZE(n)	STRINGIZE2(n)
#define STRINGIZE2(n)	#n

char PROGRAMNAME[] = "ihxtobin";

int main(int argc, char *argv[])
{
	int c;
	int minaddr = 0xFFFF, maxaddr = 0x0000;
	unsigned char checksum = 0;
	int len, addr = 0, type;
	unsigned char fillbyte = 0x00;
	enum { STATE_COLON, STATE_LEN, STATE_ADDR, STATE_TYPE,
	  STATE_DATA, STATE_CHECKSUM, STATE_DONE } state = STATE_COLON;
	unsigned char mem[0x10000];
	
	memset(mem, fillbyte, 0x10000);
	
	while ((c = getchar()) != EOF && state != STATE_DONE) {
		switch (state) {
		case STATE_COLON:
			if (c == ':')
				++state;
			break;
		
		case STATE_LEN: {
			char lenstr[3];
			ungetc(c, stdin);
			if (fgets(lenstr, 3, stdin) == NULL)
				break;
			/* fprintf(stderr,"len = '%s' ", lenstr); */
			if (sscanf(lenstr, "%X", &len) == EOF)
				break;
			/* fprintf(stderr,"(%02X) ", len); */
			++state;
			break;
		}
		
		case STATE_ADDR: {
			char addrstr[5];
			ungetc(c, stdin);
			if (fgets(addrstr, 5, stdin) == NULL)
				break;
			/* fprintf(stderr,"addr = '%s' ", addrstr); */
			if (sscanf(addrstr, "%X", &addr) == EOF)
				break;
			/* fprintf(stderr,"(%04X) ", addr); */
			++state;
			break;
		}
		
		case STATE_TYPE: {
			char typestr[3];
			ungetc(c, stdin);
			if (fgets(typestr, 3, stdin) == NULL)
				break;
			/* fprintf(stderr,"type = '%s' ", typestr); */
			if (sscanf(typestr, "%X", &type) == EOF)
				break;
			/* fprintf(stderr,"(%02X) ", type); */
			switch (type) {
			case 0x00:
				if (addr < minaddr)
					minaddr = addr;
				if (addr + len > maxaddr)
					maxaddr = addr + len;
				++state;
				break;
			case 0x01:
				state = STATE_DONE;
				break;
			case 0x02: case 0x04:
				fprintf(stderr, "%s: record type %02X not supported yet. Sorry.\n", PROGRAMNAME, type);
				return -1;
			default:
				fprintf(stderr, "%s: invalid record type %02X\n", PROGRAMNAME, type);
				return -1;
			}
			break;
		}
		
		case STATE_DATA: {
			unsigned char *m = 0;
			char datastr[3];
			int n;
			checksum = 0;
			ungetc(c, stdin);
			for (m = mem + addr; m < mem + addr + len; ++m) {
				if (fgets(datastr, 3, stdin) == NULL)
					break;
				if (sscanf(datastr, "%X", &n) == EOF)
					break;
				
				*m = n;
				checksum += n;
			}
			++state;
			break;
		}
		
		case STATE_CHECKSUM: {
			char csstr[3];
			int cs;
			
			ungetc(c, stdin);
			if (fgets(csstr, 3, stdin) == NULL)
				break;
			if (sscanf(csstr, "%X", &cs) == EOF)
				break;
			/* fprintf(stderr, "cs = '%s' (%02X) ", csstr, cs); */
			
			checksum += cs+len+addr+(addr>>8)+type;
			if (checksum) {
				fprintf(stderr, "%s: checksum error (%02X)", PROGRAMNAME, checksum);
			/*else
				fputs("checksum ok        ", stderr);*/
				fprintf(stderr, " at %04X\n", addr);
			}
			
			state = STATE_COLON;
			break;
		}
		default:
			fprintf(stderr, "%s: coding error: illegal state ("__FILE__", "STRINGIZE(__LINE__)")\n", PROGRAMNAME);
		}
	}
	
	/* fprintf(stderr, "minaddr = %04X, maxaddr = %04X\n", minaddr, maxaddr); */
	for (addr = minaddr; addr < maxaddr; ++addr)
		putchar(mem[addr]);
		/*printf("%02X", mem[addr]);*/
	
	return 0;
}