/*
 * excellon.c - KiCad drill file input
 *
 * Written 2010-2011 by Werner Almesberger
 * Copyright 2010-2011 Werner Almesberger
 *
 * 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.
 */

/*
 * KiCad drill files are in the Excellon format. The format is described here:
 *
 * http://www.excellon.com/manuals/program.htm
 *
 * Note that drl2gp currently only implements the subset necessary to process
 * the KiCad drill files encountered in a few projects, may not work correctly
 * for drill files from other projects, and will almost certainly fail in
 * tool-shattering ways when fed excellon files from other sources.
 */


#include <stdlib.h>
#include <stdio.h>
#include <ctype.h>
#include <assert.h>

#include "excellon.h"


#define	MAX_TOOL	20


static double tool_d[MAX_TOOL+1];
static int lineno = 1;
static struct path *paths, **anchor;


#define	IN2MM(in)	((in)*25.4)
#define	MIL2MM(mil)	IN2MM((mil)/1000)


/* ----- header parsing ---------------------------------------------------- */


static void header(FILE *file)
{
	enum {
		ts_nl,		/* at beginning of line */
		ts_t,		/* seen a ^T */
		ts_metric,	/* parsing METRIC,... */
		ts_inch,	/* parsing INCH,... */
		ts_tc,		/* seen ^T\d+C */
		ts_skip,	/* skip to next \n */
	} state = ts_nl;
	int c, tool;
	double f = 1;
	double tmp;
	const char *next = NULL;
	int metric = 1;

	while ((c = fgetc(file)) != EOF) {
		switch (state) {
		case ts_nl:
			switch (c) {
			case 'T':
				state = ts_t;
				tool = 0;
				break;
			case 'I':
				state = ts_inch;
				next = "NCH";
				break;
			case 'M':
				state = ts_metric;
				next = "ETRIC";
				break;
			case '%':
				return;
			case '\n':
				lineno++;
				break;
			default:
				state = ts_skip;
				break;
			}
			break;
		case ts_inch:
			if (c == ',')
				metric = 0;
			else {
				if (c == *next++)
					break;
			}
			state = ts_skip;
			break;
		case ts_metric:
			if (c == ',')
				metric = 1;
			else {
				if (c == *next++)
					break;
			}
			state = ts_skip;
			break;
		case ts_t:
			if (isdigit(c))
				tool = tool*10+c-'0';
			else if (c != 'C')
				state = ts_skip;
			else {
				assert(c != '\n');
				if (tool > MAX_TOOL) {
					fprintf(stderr,
					    "tool index %d too large (> %d)\n",
					    tool, MAX_TOOL);
					exit(1);
				}
				tool_d[tool] = 0;
				f = 1;
				state = ts_tc;
			}
			break;
		case ts_tc:
			if (isdigit(c)) {
				tmp = c-'0';
				if (!metric)
					tmp = IN2MM(tmp);
				if (f == 1)
					tool_d[tool] =
					    tool_d[tool]*10+tmp;
				else {
					tool_d[tool] += f*tmp;
					f /= 10;
				}
			} else if (c == '.') {
				f = 0.1;
			} else if (c == '\n') {
				lineno++;
				state = ts_nl;
			} else {
				state = ts_skip;
			}
			break;
		default:
			if (c == '\n') {
				lineno++;
				state = ts_nl;
			} else {
				state = ts_skip;
			}
		}
	}
}


/* ----- body parsing ------------------------------------------------------ */


static int do_cmd(char cmd, double v, int nl)
{
	static int metric = 1;
	static int slotting = 0;
	static double x = 0, y = 0, x0 = 0, d = 0;
	int n = v;

	switch (cmd) {
	case 'M':
		switch (n) {
		case 30:	/* end of program */
			return 0;
		case 47:	/* operator message */
			break;
		case 71:	/* metric measuring mode */
			metric = 1;
			break;
		case 72:	/* inch measuring mode */
			metric = 0;
			break;
		default:
			fprintf(stderr,
			    "unrecognized command M%d at line %d\n",
			    n, lineno);
			exit(1);
		}
		break;
	case 'G':
		switch (n) {
		case 5:		/* drill mode */
			break;
		case 85:	/* slot */
			x0 = x;
			slotting = 1;
			break;
		default:
			fprintf(stderr,
			    "unrecognized command G%d at line %d\n",
			    n, lineno);
			exit(1);
		}
		break;
	case 'T':
		if (!n) {
			d = 0;
			break;
		}
		if (n < 1 || n > MAX_TOOL || !tool_d[n]) {
			fprintf(stderr, "invalid tool T%d at line %d\n",
			    n, lineno);
			exit(1);
		}
		d = tool_d[n];
		break;
	case 'X':
		x = metric ? v : IN2MM(v);
		break;
	case 'Y':
		if (!metric)
			v = IN2MM(v);
		if (slotting) {
			*anchor = path_new(d/2);
			path_add(*anchor, x0, y, 0);
			path_add(*anchor, x, v, 0);
			anchor = &(*anchor)->next;
			slotting = 0;
			break;
		}
		if (nl) {
			assert(d);
			*anchor = path_new(d/2);
			path_add(*anchor, x, v, 0);
			anchor = &(*anchor)->next;
			break;
		}
		y = v;
		break;
	default:
		fprintf(stderr, "unrecognized command \"%c\" at line %d\n",
		    cmd, lineno);
		exit(1);
	}
	return 1;
}


static void body(FILE *file)
{
	char cmd = 0;
	double v = 0, f = 1;
	int c, s = 0;

	while ((c = fgetc(file)) != EOF) {
		if (c == '\n') {
			lineno++;
			if (cmd)
				do_cmd(cmd, s ? -v : v, 1);
			cmd = 0;
		} else if (isdigit(c)) {
			if (f == 1)
				v = v*10+c-'0';
			else {
				v += f*(c-'0');
				f /= 10;
			}
		} else if (c == '.') {
			f = 0.1;
		} else if (c == '-') {
			s = !s;
		} else {
			if (cmd)
				if (!do_cmd(cmd, s ? -v : v, 0))
					return;
			cmd = c;
			v = 0;
			f = 1;
			s = 0;
		}
	}
}


struct path *excellon_read(const char *name)
{
	FILE *file;

	file = name ? fopen(name, "r") : stdin;
	if (!file) {
		perror(name);
		exit(1);
	}

	lineno = 1;
	paths = NULL;
	anchor = &paths;

	header(file);
	body(file);

	fclose(file);
	return paths;
}