refactor(parser): rewrite some parts of code

schedule-parser/benches/parse.rs

@@ -0,0 +1,12 @@
+use criterion::{Criterion, criterion_group, criterion_main};
+
+use schedule_parser::parse_xls;
+
+pub fn bench_parse_xls(c: &mut Criterion) {
+    let buffer: Vec<u8> = include_bytes!("../../schedule.xls").to_vec();
+
+    c.bench_function("parse_xls", |b| b.iter(|| parse_xls(&buffer).unwrap()));
+}
+
+criterion_group!(benches, bench_parse_xls);
+criterion_main!(benches);