26 lines
719 B
Rust
26 lines
719 B
Rust
use std::env::var as envvar;
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use std::path::Path;
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use std::fs;
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const ASCII_UPPER_A: u8 = 65;
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const ASCII_LOWER_A: u8 = 97;
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const ASCII_0: u8 = 48;
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pub fn day_input(day: u8) -> String {
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let home = &envvar("HOME").unwrap();
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let home_path = Path::new(home);
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let path_buf = home_path.join(format!("./.cache/aoc2021/{0}.input", day));
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let file_path = path_buf.to_str().unwrap();
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fs::read_to_string(file_path).unwrap()
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}
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pub const fn hex_val(c: char) -> Result<u8, &'static str> {
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match c {
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'A'..='F' => Ok(c as u8 - ASCII_UPPER_A + 10),
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'a'..='f' => Ok(c as u8 - ASCII_LOWER_A + 10),
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'0'..='9' => Ok(c as u8 - ASCII_0 as u8),
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_ => Err("invalid hex char"),
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}
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}
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