adventofcode2022/day06/common.rs

45 lines
1.4 KiB
Rust

// Copyright 2022 Christian Ulrich
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
use std::io::{self, Read};
pub struct DatastreamWindows<const N: usize> {
window: [u8; N],
}
impl<const N: usize> DatastreamWindows<N> {
pub fn from_stdin() -> Result<Self, &'static str> {
let mut window = [0; N];
io::stdin()
.read_exact(&mut window[1..N])
.map_err(|_| "not enough data available")?;
Ok(Self { window: window })
}
}
impl<const N: usize> Iterator for DatastreamWindows<N> {
type Item = [u8; N];
fn next(&mut self) -> Option<Self::Item> {
for byte in io::stdin().bytes() {
let byte = byte.unwrap();
self.window.rotate_left(1);
self.window[N - 1] = byte;
return Some(self.window);
}
None
}
}