thue_morse 0.1.0

A library for generating Thue-Morse number sequences for different bases.
Documentation 
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pub struct ThueMorseProvider {
    base: u32,
}

impl ThueMorseProvider {
    pub fn new(base: u32) -> Self {
        Self {
            base,
        }
    }
    #[inline(always)]
    pub fn get_value(&self, index: usize) -> u32 {
        println!("getting value for index {index}");
        match self.base {
            2 => {
                index.count_ones() % 2
            },
            base => {
                let mut index = index;
                let base = base as usize;
                let mut result: usize = 0;
                while index > 0 {
                    result += index % base;
                    index /= base;
                }
                (result % base) as u32
            },
        }
    }
    pub fn into_iter(self) -> ThueMorseIterator {
        ThueMorseIterator {
            thue_morse_provider: self,
            index: 0,
            is_maximum_reached: false,
        }
    }
}

pub struct ThueMorseIterator {
    thue_morse_provider: ThueMorseProvider,
    index: usize,
    is_maximum_reached: bool,
}

impl Iterator for ThueMorseIterator {
    type Item = u32;

    fn next(&mut self) -> Option<Self::Item> {
        if self.is_maximum_reached {
            return None;
        }

        let value = self.thue_morse_provider.get_value(self.index);

        // if this is the last valid value we can return, return None for any future iterations
        match self.index.checked_add(1) {
            Some(next_index) => {
                self.index = next_index;
            },
            None => {
                self.is_maximum_reached = true;
            },
        }

        Some(value)
    }
}

#[cfg(test)]
mod tests {
    use crate::*;

    #[test]
    fn test_r2n8_binary() {
        let provider = ThueMorseProvider::new(2);
        assert_eq!(0, provider.get_value(0));
        assert_eq!(1, provider.get_value(1));
        assert_eq!(1, provider.get_value(2));
        assert_eq!(0, provider.get_value(3));
        assert_eq!(1, provider.get_value(4));
        assert_eq!(0, provider.get_value(5));
        assert_eq!(0, provider.get_value(6));
        assert_eq!(1, provider.get_value(7));
    }

    #[test]
    fn test_w8m2_trinary() {
        let expected_values = [
            0u32,
            1,
            2,
            1,
            2,
            0,
            2,
            0,
            1,
            1,
            2,
            0,
            2,
            0,
            1,
            0,
            1,
            2,
            2,
            0,
            1,
            0,
            1,
            2,
            1,
            2,
            0,
        ];
        let iterator = ThueMorseProvider::new(3).into_iter();
        for (expected_value, actual_value) in expected_values.into_iter().zip(iterator) {
            println!("comparing {} to {}", actual_value, expected_value);
            assert_eq!(expected_value, actual_value);
        }
    }
    #[test]
    fn test_j1v5_five() {
        let expected_values = [0, 1, 2, 3, 4, 1, 2, 3, 4, 0, 2, 3, 4, 0, 1, 3, 4, 0, 1, 2, 4, 0, 1, 2, 3, 1, 2, 3, 4, 0];
        let iterator = ThueMorseProvider::new(5).into_iter();
        for (expected_value, actual_value) in expected_values.into_iter().zip(iterator) {
            println!("comparing {} to {}", actual_value, expected_value);
            assert_eq!(expected_value, actual_value);
        }
    }
}