| 55 | type Error = String; |
| 56 | |
| 57 | fn try_from(s: &str) -> Result<Self, Self::Error> { |
| 58 | let alphabet: Vec<char> = s.chars().collect(); |
| 59 | let mut unicode = vec![false; MAX_VALUE]; |
| 60 | for &c in &alphabet { |
| 61 | if unicode[c as usize] { |
| 62 | return Err(format!("Illegal alphabet: repeated character = {:?}", c)); |
| 63 | } |
| 64 | unicode[c as usize] = true; //set code point |
| 65 | } |
| 66 | |
| 67 | let radix = alphabet.len(); |
| 68 | let mut inverse = vec![-1; MAX_VALUE]; |
| 69 | for i in 0..radix { |
| 70 | inverse[alphabet[i] as usize] = i as i32; |
| 71 | } |
| 72 | |
| 73 | Ok(Self { |
| 74 | alphabet, |
| 75 | inverse, |
| 76 | radix, |
| 77 | }) |
| 78 | } |
| 79 | } |
| 80 | |
| 81 | impl TryFrom<u16> for Alphabet { |