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pub const BITCOIN: &[u8; 58] = b"123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";
pub const RIPPLE: &[u8; 58] = b"rpshnaf39wBUDNEGHJKLM4PQRST7VWXYZ2bcdeCg65jkm8oFqi1tuvAxyz";
pub const FLICKR: &[u8; 58] = b"123456789abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ";
pub const SKYWELL: &[u8; 58] = b"jpshnaf39wBUDNEGHJKLM4PQRST7VWXYZ2bcdeCg65rkm8oFqi1tuvAxyz";
mod traits;
pub use traits::{Encode, Decode};
use traits::generate_alpha_map;
pub struct BaseX <'a> {
pub alphabet: &'a [u8],
}
impl <'a> BaseX <'a> {
pub fn new(alphabet: &'a [u8]) -> Self {
BaseX {
alphabet: alphabet,
}
}
}
impl <'a> Encode for BaseX <'a>{
type Output = String;
fn encode(&self, source: &[u8]) -> String {
let base = self.alphabet.len() as u16;
let mut digits: Vec<u16> = vec![0u16; 1];
let mut i = 0;
while i < source.len() {
let mut j = 0;
let mut carry: u16 = source[i] as u16;
let digits_len = digits.len();
while j < digits_len {
carry += digits.as_slice()[j] << 8;
digits.as_mut_slice()[j] = carry % (base as u16);
carry = (carry / (base as u16)) | 0;
j += 1;
}
while carry > 0 {
digits.push(carry % (base as u16));
carry = (carry / base) | 0;
}
i += 1;
}
let mut string = "".to_string();
let mut k = 0;
while source[k] == 0 && k < source.len() - 1 {
string.push(self.alphabet[0] as char);
k += 1;
}
let mut q: i32 = (digits.len() - 1) as i32;
while q >= 0 {
let uu: u8 = self.alphabet[digits[q as usize] as usize];
let xx = uu as char;
string.push( xx );
q -= 1;
}
string
}
}
impl <'a> Decode for BaseX <'a> {
type Output = Option<Vec<u8>>;
fn decode(&self, string: String) -> Option<Vec<u8>> {
if string.len() == 0 { return None; }
let alphabet_map = generate_alpha_map(self.alphabet);
let base = self.alphabet.len() as u16;
let ledger = self.alphabet[0] as char;
let mut bytes: Vec<u8> = vec![];
let mut i = 0;
while i < string.len() {
let c = string.as_str().chars().nth(i).unwrap();
let val = alphabet_map.get(&c);
if val.is_none() {
return None;
}
let mut j = 0;
let mut carry: u16 = *val.unwrap() as u16;
while j < bytes.len() {
carry += bytes[j] as u16 * base;
bytes[j] = (carry as u8) & 0xff;
carry >>= 8;
j += 1;
}
while carry > 0 {
bytes.push((carry as u8) & 0xff );
carry >>= 8;
}
i += 1;
}
let mut k = 0;
while string.as_str().chars().nth(k).unwrap() == ledger && k < string.len() - 1 {
bytes.push(0);
k += 1;
}
bytes.as_mut_slice().reverse();
Some(bytes)
}
}
#[cfg(test)]
mod test_set {
use super::*;
#[test]
fn encode_test() {
let src = vec![28, 215, 33, 155];
let encoded = BaseX::new(BITCOIN).encode(&src);
assert_eq!(encoded, "jkuzA".to_string());
}
#[test]
fn decode_test() {
let src = "jkuzA".to_string();
let decoded = BaseX::new(BITCOIN).decode(src);
assert_eq!(decoded, Some(vec![28, 215, 33, 155]));
}
}