/*
Base-36 encoding/decoding in Rust using u128
(limited to inputs that fit into 128 bits)
*/
const BASE36_DIGITS: &str = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
fn encode_to_base36(text: &str) -> String {
let bytes = text.as_bytes();
// Convert bytes → u128 (base-256)
let mut n: u128 = 0;
for &b in bytes {
n = n * 256 + b as u128;
}
// Convert u128 → Base-36
if n == 0 {
return "0".to_string();
}
let mut encoded = String::new();
while n > 0 {
let rem = (n % 36) as usize;
encoded.push(BASE36_DIGITS.chars().nth(rem).unwrap());
n /= 36;
}
encoded.chars().rev().collect()
}
fn decode_from_base36(encoded: &str) -> String {
let encoded = encoded.to_uppercase();
// Convert Base-36 → u128
let mut n: u128 = 0;
for c in encoded.chars() {
let digit = BASE36_DIGITS.find(c).unwrap() as u128;
n = n * 36 + digit;
}
// Convert u128 → bytes (base-256)
if n == 0 {
return String::new();
}
let mut bytes: Vec<u8> = Vec::new();
while n > 0 {
let rem = (n % 256) as u8;
bytes.push(rem);
n /= 256;
}
bytes.reverse();
String::from_utf8(bytes).unwrap()
}
fn main() {
let text = "Hello Universe!";
let encoded = encode_to_base36(text);
let decoded = decode_from_base36(&encoded);
println!("Original: {}", text);
println!("Base-36 encoded: {}", encoded);
println!("Decoded: {}", decoded);
}
/*
run:
Original: Hello Universe!
Base-36 encoded: LP4N024HJ1YVBVD84Y8TYQP
Decoded: Hello Universe!
*/
