From 9e22d912b204c5bf5ab760d7d907076a562f8ed4 Mon Sep 17 00:00:00 2001
From: Timo Kokkonen <timo.t.kokkonen@iki.fi>
Date: Sun, 6 Oct 2013 16:46:58 +0300
Subject: [PATCH] Add command line parsing

Add generic commnd line parsing code for adjusting the run time
configurable parameters.

Signed-off-by: Timo Kokkonen <timo.t.kokkonen@iki.fi>
---
 Makefile  |  2 +-
 main.c    | 19 +++++++++----------
 options.c | 56 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 options.h | 12 ++++++++++++
 4 files changed, 78 insertions(+), 11 deletions(-)
 create mode 100644 options.c
 create mode 100644 options.h

diff --git a/Makefile b/Makefile
index bcea3eb..e02d333 100644
--- a/Makefile
+++ b/Makefile
@@ -2,7 +2,7 @@ CC=gcc
 LD=ld
 CFLAGS=-Wall -O2 -g -fPIC
 
-LOG-PLOTTER_OBJS = baud.o main.o
+LOG-PLOTTER_OBJS = baud.o main.o options.o
 
 ALL_OBJS = $(LOG-PLOTTER_OBJS)
 ALL_DEBS = $(patsubst %.o,.%.o.d,$(ALL_OBJS))
diff --git a/main.c b/main.c
index dd6c7c0..d81f733 100644
--- a/main.c
+++ b/main.c
@@ -2,30 +2,29 @@
 #include <unistd.h>
 #include <sys/epoll.h>
 
+#include "options.h"
 #include "baud.h"
 
 int main(int argc, char *argv[])
 {
 	struct epoll_event ev;
+	struct plotter_options options;
 	int fd, baud, ret;
 	int epoll_fd;
-	char *device;
 	char buf[256];
 
-	if (argc < 2) {
-		printf("Usage: %s SERIAL_DEVICE\n", argv[0]);
-		return 1;
-	}
 
-	baud = 128000;
-	device = argv[1];
+	if (read_args(argc, argv, &options))
+		return 1;
 
-	fd = open_at_baud(device, &baud);
+	baud = options.baud_rate;
+	fd = open_at_baud(options.device_path, &baud);
 	if (fd < 0)
 		return 1;
 
-	if (baud != 128000) {
-		printf("Failed to set baudrate to 128000, only got %d\n", baud);
+	if (baud != options.baud_rate) {
+		printf("Failed to set baudrate to %d, only got %d\n",
+			options.baud_rate, baud);
 		close(fd);
 		return 1;
 	}
diff --git a/options.c b/options.c
new file mode 100644
index 0000000..38b29a3
--- /dev/null
+++ b/options.c
@@ -0,0 +1,56 @@
+#include <getopt.h>
+#include <string.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "options.h"
+
+static void set_default_options(struct plotter_options *opts)
+{
+	bzero(opts, sizeof(*opts));
+
+	opts->baud_rate = 128000;
+	opts->device_path = "/dev/ttyUSB0";
+}
+
+int read_args(int argc, char *argv[], struct plotter_options *opts)
+{
+	int option_index = 0, c;
+	static struct option long_options[] = {
+		{ .val = 'd', .name = "device", .has_arg = 1, },
+		{ .val = 'o', .name = "output", .has_arg = 1 },
+		{ .val = 'o', .name = "baud", .has_arg = 1 },
+	};
+	char short_options[] = "d:o:b:";
+
+	set_default_options(opts);
+
+	while (1) {
+		c = getopt_long(argc, argv, short_options, long_options,
+				&option_index);
+
+		if (c == -1)
+			break;
+
+		switch (c) {
+		case 'd':
+			opts->device_path = optarg;
+			break;
+		case 'o':
+			opts->output_path = optarg;
+			break;
+		case 'b':
+			opts->baud_rate = atoi(optarg);
+			break;
+		case '?':
+			return -1;
+		}
+	}
+
+	while (optind < argc) {
+		/* The rest of the options, ignored */
+		optind++;
+	}
+
+	return 0;
+}
diff --git a/options.h b/options.h
new file mode 100644
index 0000000..5312e42
--- /dev/null
+++ b/options.h
@@ -0,0 +1,12 @@
+#ifndef _OPTIONS_H
+#define _OPTIONS_H
+
+struct plotter_options {
+	char *device_path;
+	char *output_path;
+	int baud_rate;
+};
+
+int read_args(int argc, char *argv[], struct plotter_options *opts);
+
+#endif
-- 
2.44.0