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

typedef int (*config_parser_fn_t)(char *, void *);

struct parse_table_entry {
	char *token;
	void *dest;
	config_parser_fn_t parser;
};

struct config_data cd;

struct config_data {
	char *interfaces;
	long int retries;
};

int parse_int(char *str, void *dst) {
	*((long int *)dst) = strtoul(str, NULL, 10);
	return 0;
}

int parse_str(char *str, void *dst) {
	*((char **)dst) = strdup(str);	
	return 0;
}

struct parse_table_entry pt[] = {
	{ "interfaces", &cd.interfaces, parse_str },
	{ "retries", &cd.retries, parse_int },
};

int main(int argc, char *argv[]) {

	FILE *input;
	char line[128];

	input = fopen("./config_file", "r");
	if (!input) {
		fprintf(stderr, "Unable to open ./config_file: %s\n", strerror(errno));
		return -1;
	}

	while (fgets(line, sizeof(line), input)	!= NULL) {
		int i, toklen;

		for (i = 0; i < sizeof(pt) / sizeof(struct parse_table_entry); i++) {
			toklen = strlen(pt[i].token);
			if (strncmp(pt[i].token, line, toklen) == 0) {
				if (pt[i].parser(line + toklen + 1, pt[i].dest) != 0) {
					fprintf(stderr, "Unexpected input. Aborting.\n");
					break;
				}
			}
		}
	}

	printf("interfaces: %s\n", (cd.interfaces) ? cd.interfaces : "unset");
	printf("retries: %d\n", cd.retries);

	fclose(input);
}