1 files changed, 101 insertions, 0 deletions
diff --git a/src/main.c b/src/main.c
new file mode 100644
index 0000000..ee80826
--- /dev/null
+++ b/src/main.c
@@ -0,0 +1,101 @@
+#include <errno.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+static struct settings_s {
+	size_t fetchpos;
+	size_t fetchto;
+	char *filein;
+	char *fileout;
+	int mode;
+} settings = {0};
+
+static int parseargs(int argc, char **argv, struct settings_s * settings);
+void printhelp(const char * const name);
+
+int main(int argc, char **argv)
+{
+	int ret = 0;
+
+	if ((ret = parseargs(argc, argv, &settings))) {
+		goto out;
+	}
+
+out:
+	return ret;
+}
+
+static int parseargs(int argc, char **argv, struct settings_s * settings)
+{
+	struct settings_s s = {0};
+	ssize_t i;
+	int ret = 0;
+
+	if (argc < 2) {
+		goto err;
+	}
+
+	for (i = 1; i < argc - 1; ++i) {
+		if (!(strcmp(argv[i], "--sort"))) {
+			s.mode = 0;
+		} else if (!(strcmp(argv[i], "--fetch"))) {
+			s.mode = 1;
+		} else if (!(strncmp(argv[i], "--position=", 11))) {
+			if (strlen(argv[i]) > 11) {
+				s.fetchpos = strtoul(argv[i] + 11, NULL, 10);
+			} else {
+				goto err;
+			}
+		} else if (!(strncmp(argv[i], "--num=", 6))) {
+			if (strlen(argv[i]) > 6) {
+				s.fetchto = strtoul(argv[i] + 11, NULL, 10);
+			} else {
+				goto err;
+			}
+		} else if (!(strncmp(argv[i], "--out=", 6))) {
+			if (strlen(argv[i]) > 6) {
+				s.fileout = argv[i] + 6;
+			} else {
+				goto err;
+			}
+		} else {
+			goto err;
+		}
+	}
+
+	if (!strncmp(argv[i], "--", 2)) {
+		goto err;
+	} else {
+		s.filein = argv[i];
+	}
+
+	*settings = s;
+	if (0) {
+err:
+		ret = EINVAL;
+		printhelp(*argv);
+	}
+
+	return ret;
+}
+
+void printhelp(const char * const name)
+{
+	printf(	"This is a mergesort program and such\n"
+		"\n"
+		"usage:\t%s [options]\n FILE"
+		"\n"
+		"Options:\n"
+		" --sort              sort mode (default)\n"
+		" --fetch             fetch element\n"
+		" --position=<num>    fetch element from position <num>\n"
+		" --num=<num>         <num> of elements to fetch\n"
+		" --out=<name>        write output to <name> file\n"
+		"\n"
+		"In case more than one same option is provided, the last one take precedence\n"
+		"\n",
+			name);
+	return;
+}