/*
 * gerber.c - Gerber file input
 *
 * Written 2010 by Werner Almesberger
 * Copyright 2010 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.
 */

/*
 * Note: this is limited to the Gerber produced by KiCad for the PCB Edge
 * layer. Furthermore, we ignore the tool diameter for now.
 *
 * The relevant details are nicely explained at
 * http://www.pcbmilling.com/Examples of Gerber and Excellon Data Files.htm
 */

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

#include "path.h"
#include "gerber.h"


/* KiCad Gerber uses 0.1 mil units */

#define	KU2MM(in)	((in)/10000.0*25.4)


struct path *gerber_read(const char *name, double r_tool_default)
{
	FILE *file;
	int lineno = 0;
	char buf[1024];
	struct path *paths = NULL, **anchor = &paths, *path = NULL;
	double start_x = 0, start_y = 0;
	int xi, yi, d;
	double x, y;

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

	while (fgets(buf, sizeof(buf), file)) {
		lineno++;
		if (!strncmp(buf, "%FS", 3)) {
			if (strcmp(buf, "%FSLAX34Y34*%\n")) {
				fprintf(stderr,
				    "unrecognized format %s\n", buf);
				exit(1);
			}
			continue;
		}
		if (!strncmp(buf, "%MO", 3)) {
			if (strcmp(buf, "%MOIN*%\n")) {
				fprintf(stderr,
				    "unrecognized mode %s\n", buf);
				exit(1);
			}
			continue;
		}
		if (sscanf(buf, "X%dY%dD%d*\n", &xi, &yi, &d) != 3)
			continue;
		x = KU2MM(xi);
		y = KU2MM(yi);
		switch (d) {
		case 1:
			if (!path) {
				path = path_new(r_tool_default, name);
				*anchor = path;
				anchor = &path->next;
				path_add(path, start_x, start_y, 0);
			}
			path_add(path, x, y, 0);
			break;
		case 2:
			path = NULL;
			start_x = x;
			start_y = y;
			break;
		default:
			fprintf(stderr, "don't recognize D%d\n", d);
			exit(1);
		}
	}
	fclose(file);
	return path_connect(paths);
}