62 lines
1.7 KiB
Rust
62 lines
1.7 KiB
Rust
use {
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std::{
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error::Error,
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fmt,
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fs::File,
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io::{self, Read},
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time::{SystemTime, UNIX_EPOCH},
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},
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tinyrand::{RandRange, Seeded, StdRand},
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};
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const ALPHABET: [char; 67] = [
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'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's',
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't', 'u', 'v', 'w', 'x', 'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L',
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'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', '0', '1', '2', '3', '4',
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'5', '6', '7', '8', '9', '@', '%', '&', '=', '+',
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];
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#[derive(Clone, Debug)]
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pub struct Id {
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pub time: u64,
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pub id: [char; 8],
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}
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impl fmt::Display for Id {
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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write!(f, "{}.", self.time)?;
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self.id.iter().try_for_each(|c| write!(f, "{c}"))
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}
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}
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impl Id {
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pub fn new() -> Result<Self, Box<dyn Error>> {
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let time = SystemTime::now().duration_since(UNIX_EPOCH)?.as_secs();
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let mut rand = StdRand::seed(random_seed()?);
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let mut id = ['0', '0', '0', '0', '0', '0', '0', '0'];
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for item in &mut id {
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if let Some(c) = ALPHABET.get(rand.next_range(0..68)) {
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*item = *c;
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}
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}
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Ok(Self { time, id })
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}
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}
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fn u64_from_bytes(b: [u8; 8]) -> u64 {
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u64::from(b[0])
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| (u64::from(b[1]) << 8)
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| (u64::from(b[2]) << 16)
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| (u64::from(b[3]) << 24)
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| (u64::from(b[4]) << 32)
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| (u64::from(b[5]) << 40)
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| (u64::from(b[6]) << 48)
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| (u64::from(b[7]) << 56)
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}
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fn random_seed() -> io::Result<u64> {
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let mut buf = [0, 0, 0, 0, 0, 0, 0, 0];
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let mut fd = File::open("/dev/urandom")?;
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fd.read_exact(&mut buf)?;
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Ok(u64_from_bytes(buf))
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}
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