fix type inconsistancies

file.c

@@ -11,7 +11,7 @@ void populate_buffer(char *buffer, char pattern) {
 	*(buffer + i + 1) = '\0';
 }
 
-int read_file_into_buffer(char *filename, char *buffer, int length) {
+int read_file_into_buffer(char *filename, char *buffer, ssize_t length) {
 	int i;
 	if (!access(filename, F_OK) == 0) {
 		populate_buffer(buffer, '?');