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/// Converts unsigned integers into a string representation with some base.
/// Bases up to and including 36 can be used for case-insensitive things.
use std::str;
#[cfg(test)]
mod tests;
pub const MAX_BASE: usize = 64;
pub const ALPHANUMERIC_ONLY: usize = 62;
pub const CASE_INSENSITIVE: usize = 36;
const BASE_64: &[u8; MAX_BASE] =
b"0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ@$";
#[inline]
pub fn push_str(mut n: u128, base: usize, output: &mut String) {
debug_assert!(base >= 2 && base <= MAX_BASE);
let mut s = [0u8; 128];
let mut index = s.len();
let base = base as u128;
loop {
index -= 1;
s[index] = BASE_64[(n % base) as usize];
n /= base;
if n == 0 {
break;
}
}
output.push_str(unsafe {
// SAFETY: `s` is populated using only valid utf8 characters from `BASE_64`
str::from_utf8_unchecked(&s[index..])
});
}
#[inline]
pub fn encode(n: u128, base: usize) -> String {
let mut s = String::new();
push_str(n, base, &mut s);
s
}
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