eddie 0.4.2

#![macro_use]

mod zip;
mod buffer;

pub use zip::Zippable;
pub use buffer::Buffer;

use std::cmp::min;


macro_rules! min {
    ($x: expr) => ($x);
    ($x: expr, $($z: expr),+) => (::std::cmp::min($x, min!($($z),*)));
}


macro_rules! max {
    ($x: expr) => ($x);
    ($x: expr, $($z: expr),+) => (::std::cmp::max($x, max!($($z),*)));
}


pub fn common_prefix_size<T: Copy + PartialEq>(slice1: &[T], slice2: &[T]) -> usize {
    slice1.into_iter().zip(slice2.into_iter())
        .take_while(|(ch1, ch2)| ch1 == ch2)
        .count()
}


pub fn common_affix_sizes<T: Copy + PartialEq>(slice1: &[T], slice2: &[T]) -> (usize, usize) {
    let min_len = min(slice1.len(), slice2.len());
    let prefix = common_prefix_size(slice1, slice2);
    let suffix = slice1.into_iter().rev().zip(slice2.into_iter().rev())
        .take(min_len - prefix)
        .take_while(|(item1, item2)| item1 == item2)
        .count();
    (prefix, suffix)
}


#[cfg(test)]
mod tests {
    use super::common_affix_sizes;

    fn vec(s: &str) -> Vec<char> { s.chars().collect() }

    #[test]
    fn affix_sizes_empty() {
        let v1 = vec("");
        let sample = [
            ((0, 0), vec("")),
            ((0, 0), vec("m")),
            ((0, 0), vec("ma")),
            ((0, 0), vec("mai")),
            ((0, 0), vec("mail")),
            ((0, 0), vec("mailb")),
            ((0, 0), vec("mailbo")),
            ((0, 0), vec("mailbox")),
        ];
        for (expected, v2) in &sample {
            assert_eq!(common_affix_sizes(&v1, &v2), *expected);
            assert_eq!(common_affix_sizes(&v2, &v1), *expected);
        }
    }

    #[test]
    fn affix_sizes_equal() {
        let sample = [
            ((1, 0), vec("m")),
            ((2, 0), vec("ma")),
            ((3, 0), vec("mai")),
            ((4, 0), vec("mail")),
            ((5, 0), vec("mailb")),
            ((6, 0), vec("mailbo")),
            ((7, 0), vec("mailbox")),
        ];
        for (expected, v1) in &sample {
            assert_eq!(common_affix_sizes(&v1, &v1), *expected);
        }
    }

    #[test]
    fn affix_sizes_nonequal() {
        let sample = [
            ((0, 0), vec("m"),    vec("b")),
            ((0, 0), vec("ma"),   vec("bo")),
            ((0, 0), vec("mai"),  vec("bol")),
            ((0, 0), vec("mail"), vec("bolt")),
        ];
        for (expected, v1, v2) in &sample {
            assert_eq!(common_affix_sizes(&v1, &v2), *expected);
        }
    }

    #[test]
    fn affix_sizes_prefix() {
        let sample = [
            ((1, 0), vec("mailbox"), vec("m")),
            ((2, 0), vec("mailbox"), vec("ma")),
            ((3, 0), vec("mailbox"), vec("mai")),
            ((4, 0), vec("mailbox"), vec("mail")),
            ((5, 0), vec("mailbox"), vec("mailb")),
            ((6, 0), vec("mailbox"), vec("mailbo")),
        ];
        for (expected, v1, v2) in &sample {
            assert_eq!(common_affix_sizes(&v1, &v2), *expected);
            assert_eq!(common_affix_sizes(&v2, &v1), *expected);
        }
    }

    #[test]
    fn affix_sizes_suffix() {
        let sample = [
            ((0, 1), vec("mailbox"), vec("x")),
            ((0, 2), vec("mailbox"), vec("ox")),
            ((0, 3), vec("mailbox"), vec("box")),
            ((0, 4), vec("mailbox"), vec("lbox")),
            ((0, 5), vec("mailbox"), vec("ilbox")),
            ((0, 6), vec("mailbox"), vec("ailbox")),
        ];
        for (expected, v1, v2) in &sample {
            assert_eq!(common_affix_sizes(&v1, &v2), *expected);
            assert_eq!(common_affix_sizes(&v2, &v1), *expected);
        }
    }

    #[test]
    fn affix_sizes_sub() {
        let sample = [
            ((3, 3), vec("mailbox"), vec("mai_box")),
            ((2, 3), vec("mailbox"), vec("ma__box")),
            ((2, 2), vec("mailbox"), vec("ma___ox")),
            ((1, 2), vec("mailbox"), vec("m____ox")),
            ((1, 1), vec("mailbox"), vec("m_____x")),
        ];
        for (expected, v1, v2) in &sample {
            assert_eq!(common_affix_sizes(&v1, &v2), *expected);
            assert_eq!(common_affix_sizes(&v2, &v1), *expected);
        }
    }

    #[test]
    fn affix_sizes_add_del() {
        let sample = [
            ((3, 4), vec("mailbox"), vec("mai_lbox")),
            ((3, 3), vec("mailbox"), vec("mai_l_box")),
            ((2, 3), vec("mailbox"), vec("ma_i_l_box")),
            ((2, 2), vec("mailbox"), vec("ma_i_l_b_ox")),
            ((1, 2), vec("mailbox"), vec("m_a_i_l_b_ox")),
            ((1, 1), vec("mailbox"), vec("m_a_i_l_b_o_x")),
        ];
        for (expected, v1, v2) in &sample {
            assert_eq!(common_affix_sizes(&v1, &v2), *expected);
            assert_eq!(common_affix_sizes(&v2, &v1), *expected);
        }
    }

    #[test]
    fn affix_size_utf_multibyte() {
        let sample = [
            ((4, 0), vec("もしもし"), vec("もしもしし")),
            ((4, 0), vec("もしもし"), vec("もしもし")),
            ((2, 1), vec("もしもし"), vec("もしまし")),
            ((2, 1), vec("もしもし"), vec("もしし")),
        ];
        for (expected, v1, v2) in &sample {
            assert_eq!(common_affix_sizes(&v1, &v2), *expected);
            assert_eq!(common_affix_sizes(&v2, &v1), *expected);
        }
    }

    #[test]
    fn affix_size_mixed() {
        let sample = [
            ((0, 0), vec("ca"),        vec("abc")),
            ((2, 0), vec("a tc"),      vec("a cat")),
            ((1, 1), vec("a cat"),     vec("an abct")),
            ((0, 1), vec("crate"),     vec("trace")),
            ((0, 5), vec("captain"),   vec("ptain")),
            ((1, 2), vec("dwayne"),    vec("duane")),
            ((3, 1), vec("martha"),    vec("marhta")),
            ((0, 0), vec("kitten"),    vec("sitting")),
            ((0, 0), vec("mailbox"),   vec("boxmail")),
            ((0, 3), vec("mailbox"),   vec("alimbox")),
            ((2, 0), vec("dixon"),     vec("dicksonx")),
            ((0, 8), vec("jellyfish"), vec("smellyfish")),
        ];
        for (expected, v1, v2) in &sample {
            assert_eq!(common_affix_sizes(&v1, &v2), *expected);
            assert_eq!(common_affix_sizes(&v2, &v1), *expected);
        }
    }
}