rasn_compiler/intermediate/encoding_rules/
mod.rs

1pub mod per_visible;
2
3pub fn bit_length(min: i128, max: i128) -> usize {
4    let number_of_values = max - min + 1;
5    let mut power = 0;
6    while number_of_values > 2_i128.pow(power) {
7        power += 1;
8    }
9    power as usize
10}
11
12#[cfg(test)]
13mod tests {
14    use super::*;
15
16    #[test]
17    fn computes_bit_size() {
18        assert_eq!(bit_length(1, 1), 0);
19        assert_eq!(bit_length(-1, 0), 1);
20        assert_eq!(bit_length(3, 6), 2);
21        assert_eq!(bit_length(4000, 4255), 8);
22        assert_eq!(bit_length(4000, 4256), 9);
23        assert_eq!(bit_length(0, 32000), 15);
24        assert_eq!(bit_length(0, 65538), 17);
25        assert_eq!(bit_length(-1, 127), 8);
26        assert_eq!(bit_length(-900000000, 900000001), 31);
27    }
28}