vyre 0.4.0

use super::Token;

pub fn match_from(tokens: &[Token], input: &[u8], start: usize) -> Option<usize> {
    let mut positions = vec![start];
    for (token_index, token) in tokens.iter().enumerate() {
        let last_token = token_index + 1 == tokens.len();
        let mut next_positions = Vec::new();
        for pos in positions {
            match *token {
                Token::Literal(byte) if input.get(pos).is_some_and(|&value| value == byte) => {
                    next_positions.push(pos + 1);
                }
                Token::Any if pos < input.len() => next_positions.push(pos + 1),
                Token::StarLiteral(byte) => {
                    let mut end = pos;
                    next_positions.push(end);
                    while input.get(end).is_some_and(|&value| value == byte) {
                        end += 1;
                        next_positions.push(end);
                    }
                }
                Token::StarAny => {
                    if last_token {
                        next_positions.push(input.len());
                    } else {
                        next_positions.extend(pos..=input.len());
                    }
                }
                _ => {}
            }
        }
        next_positions.sort_unstable();
        next_positions.dedup();
        if next_positions.is_empty() {
            return None;
        }
        positions = next_positions;
    }
    positions.into_iter().min()
}