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pub const BASE: u8 = 62;
pub const ALPHABET: &[u8; BASE as usize] =
b"0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
pub fn number_to_digits(mut x: u128, base: u8) -> Vec<u8> {
let mut out = Vec::new();
let base = base as u128;
while x > base {
out.push((x % base) as u8);
x /= base;
}
out.push(x as u8);
out.reverse();
out
}
#[allow(dead_code)]
pub fn digits_to_number<I>(x: I, base: u8) -> u128
where I: Iterator<Item=u8> {
let base = base as u128;
x.fold(0, |out, digit| out * base + digit as u128)
}
pub fn digits_to_string<I>(x: I, alphabet: &[u8]) -> String
where I: Iterator<Item=u8> {
x.map(|d| alphabet[d as usize] as char).collect()
}
#[cfg(test)]
mod test {
use crate::base62::*;
#[test]
fn test_number_to_digits() {
assert_eq!(vec![0], number_to_digits(0, 10));
assert_eq!(vec![8], number_to_digits(8, BASE));
assert_eq!(vec![1, 2], number_to_digits(64, BASE));
assert_eq!(vec![6, 4], number_to_digits(64, 10));
}
#[test]
fn test_digits_to_number() {
assert_eq!(digits_to_number(vec![1u8, 2].into_iter(), BASE), 64);
assert_eq!(digits_to_number(vec![6u8, 4].into_iter(), 10), 64);
}
#[test]
fn test_digits_to_string() {
assert_eq!(digits_to_string(vec![1u8, 2].into_iter(), ALPHABET), "12");
}
}
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