Error out in case directory is inputted or input is 0 size

huffman.c

@@ -2,6 +2,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <sys/stat.h>
 
 #include "print_helper.h"
 
@@ -108,6 +109,18 @@ int main(int argc, char *argv[])
 		outfile = argv[2];
 	}
 
+	struct stat in_stat;
+	stat(infile, &in_stat);
+	if (!S_ISREG(in_stat.st_mode)) {
+		fprintf(stderr, "Input is not a file\n");
+		return -1;
+	}
+
+	if (in_stat.st_size == 0) {
+		fprintf(stderr, "Input file is empty\n");
+		return -1;
+	}
+
 	FILE *input = fopen(infile, "r");
 	if (!input) {
 		fprintf(stderr, "Failed to open input file\n");