Merge pull request #52 from orxfun/sort-methods

sort methods are implemented

Author: orxfun

Cargo.toml

@@ -10,8 +10,8 @@ keywords = ["vec", "array", "split", "fragments", "pinned"]
 categories = ["data-structures", "rust-patterns"]
 
 [dependencies]
-orx-pseudo-default = "1.2"
-orx-pinned-vec = "3.3"
+orx-pseudo-default = "1.4"
+orx-pinned-vec = "3.4"
 
 [[bench]]
 name = "serial_access"

src/algorithms/in_place_sort.rs

@@ -0,0 +1,240 @@
+use crate::Fragment;
+use std::cmp::Ordering::{self, *};
+
+pub fn in_place_sort_by<T, F>(fragments: &mut [Fragment<T>], mut compare: F)
+where
+    F: FnMut(&T, &T) -> Ordering,
+{
+    if fragments.len() == 0 {
+        return;
+    }
+
+    for fragment in fragments.iter_mut() {
+        fragment.sort_by(&mut compare);
+    }
+
+    let num_fragments = fragments.len();
+
+    let mut r = 0;
+    let mut c = 0;
+
+    while r < num_fragments - 1 {
+        let row_to_swap = get_row_to_swap(fragments, &mut compare, r, c);
+        if let Some(target_row) = row_to_swap {
+            let pa = std::ptr::addr_of_mut!(fragments[r][c]);
+            let pb = std::ptr::addr_of_mut!(fragments[target_row][0]);
+            // SAFETY: `pa` and `pb` have been created from safe mutable references and refer
+            // to elements in the slice and therefore are guaranteed to be valid and aligned.
+            // Note that accessing the elements behind `a` and `b` is checked and will
+            // panic when out of bounds.
+            unsafe { std::ptr::swap(pa, pb) };
+
+            let fragment_right = &fragments[target_row][1..];
+            let value = &fragments[target_row][0];
+            let position_to_insert = find_position_to_insert(fragment_right, &mut compare, value);
+            if let Some(p) = position_to_insert {
+                for i in 0..p {
+                    fragments[target_row].swap(i, i + 1);
+                }
+            }
+        }
+
+        match c == fragments[r].len() - 1 {
+            true => (r, c) = (r + 1, 0),
+            false => c += 1,
+        }
+    }
+}
+
+fn get_row_to_swap<T, F>(
+    fragments: &[Fragment<T>],
+    compare: &mut F,
+    r: usize,
+    c: usize,
+) -> Option<usize>
+where
+    F: FnMut(&T, &T) -> Ordering,
+{
+    let mut r_best = r + 1;
+    match r_best == fragments.len() {
+        true => None,
+        false => {
+            let mut best = &fragments[r_best][0];
+            for q in (r_best + 1)..fragments.len() {
+                if let Less = compare(&fragments[q][0], best) {
+                    (best, r_best) = (&fragments[q][0], q);
+                }
+            }
+
+            match compare(best, &fragments[r][c]) {
+                Less => Some(r_best),
+                _ => None,
+            }
+        }
+    }
+}
+
+fn find_position_to_insert<T, F>(fragment: &[T], compare: &mut F, value: &T) -> Option<usize>
+where
+    F: FnMut(&T, &T) -> Ordering,
+{
+    match fragment.len() {
+        0 => None,
+        _ => match compare(unsafe { fragment.get_unchecked(0) }, value) {
+            Equal | Greater => None,
+            Less => {
+                let mut target = 0;
+                let mut size = fragment.len();
+                let mut left = 0;
+                let mut right = size;
+                while left < right {
+                    let mid = left + size / 2;
+
+                    match compare(unsafe { fragment.get_unchecked(mid) }, value) {
+                        // Equal => return Some(mid),
+                        Greater | Equal => right = mid,
+                        Less => {
+                            target = mid + 1;
+                            left = mid;
+                        }
+                    }
+                    if size == 1 {
+                        return Some(target);
+                    }
+                    size = right - left;
+                }
+
+                Some(target)
+            }
+        },
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::{Doubling, Growth, Linear, Recursive};
+    use test_case::test_case;
+
+    #[test]
+    fn insertion_position() {
+        let fragment: Fragment<u32> = vec![4, 7, 9, 13, 16, 17, 23].into();
+
+        let mut c = |a: &u32, b: &u32| a.cmp(b);
+        let mut pos = |val: &u32| find_position_to_insert(&fragment, &mut c, val);
+
+        assert_eq!(pos(&0), None);
+        assert_eq!(pos(&3), None);
+        assert_eq!(pos(&4), None);
+
+        assert_eq!(pos(&5), Some(1));
+        assert_eq!(pos(&6), Some(1));
+        assert_eq!(pos(&7), Some(1));
+
+        assert_eq!(pos(&8), Some(2));
+        assert_eq!(pos(&9), Some(2));
+
+        assert_eq!(pos(&10), Some(3));
+        assert_eq!(pos(&11), Some(3));
+        assert_eq!(pos(&12), Some(3));
+        assert_eq!(pos(&13), Some(3));
+
+        assert_eq!(pos(&14), Some(4));
+        assert_eq!(pos(&15), Some(4));
+        assert_eq!(pos(&16), Some(4));
+
+        assert_eq!(pos(&17), Some(5));
+
+        assert_eq!(pos(&18), Some(6));
+        assert_eq!(pos(&19), Some(6));
+        assert_eq!(pos(&20), Some(6));
+        assert_eq!(pos(&21), Some(6));
+        assert_eq!(pos(&22), Some(6));
+        assert_eq!(pos(&23), Some(6));
+
+        assert_eq!(pos(&24), Some(7));
+        assert_eq!(pos(&25), Some(7));
+        assert_eq!(pos(&26), Some(7));
+        assert_eq!(pos(&100), Some(7));
+    }
+
+    #[test]
+    fn insertion_position_with_ties() {
+        let mut c = |a: &u32, b: &u32| a.cmp(b);
+
+        let fragment: Fragment<u32> = vec![4, 7, 13, 13, 13, 17, 23].into();
+        let mut pos = |val: &u32| find_position_to_insert(&fragment, &mut c, val);
+        assert_eq!(pos(&13), Some(2));
+
+        let fragment: Fragment<u32> = vec![4, 7, 13, 13, 23, 23, 23].into();
+        let mut pos = |val: &u32| find_position_to_insert(&fragment, &mut c, val);
+        assert_eq!(pos(&23), Some(4));
+
+        let fragment: Fragment<u32> = vec![4, 4, 13, 13, 23, 23, 23].into();
+        let mut pos = |val: &u32| find_position_to_insert(&fragment, &mut c, val);
+        assert_eq!(pos(&4), None);
+    }
+
+    #[test]
+    fn sort_simple() {
+        let mut c = |a: &u32, b: &u32| a.cmp(b);
+
+        let mut fragments: Vec<Fragment<u32>> =
+            vec![vec![2, 4].into(), vec![0, 5, 6].into(), vec![1, 3].into()];
+
+        in_place_sort_by(&mut fragments, &mut c);
+
+        assert_is_sorted(fragments);
+    }
+
+    #[test_case(Doubling)]
+    #[test_case(Recursive)]
+    #[test_case(Linear::new(10))]
+    fn sort_growth(growth: impl Growth) {
+        let mut c = |a: &i32, b: &i32| a.cmp(b);
+
+        let num_fragments = 10;
+        let mut fragments: Vec<Fragment<_>> = vec![];
+
+        let mut len = 0;
+        for _ in 0..num_fragments {
+            let fragment_capacities: Vec<_> = fragments.iter().map(|x| x.capacity()).collect();
+            let mut fragment =
+                Fragment::new(growth.new_fragment_capacity_from(fragment_capacities.into_iter()));
+            for i in 0..fragment.capacity() {
+                let i = len + i;
+                let value = match i % 3 {
+                    0 => i as i32,
+                    1 => 42,
+                    _ => -(i as i32),
+                };
+                fragment.push(value);
+            }
+
+            assert_eq!(fragment.len(), fragment.capacity());
+            len += fragment.len();
+            fragments.push(fragment);
+        }
+
+        assert_eq!(fragments.len(), num_fragments);
+
+        in_place_sort_by(&mut fragments, &mut c);
+
+        assert_is_sorted(fragments);
+    }
+
+    fn assert_is_sorted<T: Ord>(fragments: Vec<Fragment<T>>) {
+        let flattened: Vec<T> = fragments.into_iter().flat_map(|x| Vec::from(x)).collect();
+
+        if flattened.is_empty() {
+            return;
+        }
+
+        let mut curr = &flattened[0];
+        for i in 1..flattened.len() {
+            let cmp = curr.cmp(&flattened[i]);
+            assert!(cmp != Greater);
+            curr = &flattened[i];
+        }
+    }
+}

src/algorithms/mod.rs

@@ -1 +1,2 @@
 pub mod binary_search;
+pub mod in_place_sort;

src/pinned_vec.rs

@@ -719,6 +719,29 @@ impl<T, G: Growth> PinnedVec<T> for SplitVec<T, G> {
     {
         algorithms::binary_search::binary_search_by(&self.fragments, f)
     }
+
+    fn sort(&mut self)
+    where
+        T: Ord,
+    {
+        algorithms::in_place_sort::in_place_sort_by(&mut self.fragments, T::cmp)
+    }
+
+    fn sort_by<F>(&mut self, compare: F)
+    where
+        F: FnMut(&T, &T) -> Ordering,
+    {
+        algorithms::in_place_sort::in_place_sort_by(&mut self.fragments, compare)
+    }
+
+    fn sort_by_key<K, F>(&mut self, mut f: F)
+    where
+        F: FnMut(&T) -> K,
+        K: Ord,
+    {
+        let compare = |a: &T, b: &T| f(a).cmp(&f(b));
+        algorithms::in_place_sort::in_place_sort_by(&mut self.fragments, compare)
+    }
 }
 
 #[cfg(test)]

tests/sort.rs

@@ -0,0 +1,33 @@
+use orx_split_vec::*;
+use std::cmp::Ordering;
+
+#[test]
+fn sort() {
+    let mut vec: SplitVec<_> = [3, 4, 1, 2, 3, 5, 8, 10, 9].into_iter().collect();
+    vec.sort();
+    assert_eq!(&vec, &[1, 2, 3, 3, 4, 5, 8, 9, 10]);
+}
+
+#[test]
+fn sort_by() {
+    let compare = |a: &i32, b: &i32| match a.cmp(b) {
+        Ordering::Less => Ordering::Greater,
+        Ordering::Greater => Ordering::Less,
+        Ordering::Equal => Ordering::Equal,
+    };
+    let mut vec: SplitVec<_> = [3, 4, 1, 2, 3, 5, 8, 10, 9].into_iter().collect();
+    vec.sort_by(compare);
+    assert_eq!(&vec, &[10, 9, 8, 5, 4, 3, 3, 2, 1]);
+}
+
+#[test]
+fn sort_by_key() {
+    let key = |a: &i32| match a % 2 {
+        0 => *a,
+        _ => -a,
+    };
+
+    let mut vec: SplitVec<_> = [3, 4, 1, 2, 3, 5, 8, 10, 9].into_iter().collect();
+    vec.sort_by_key(key);
+    assert_eq!(&vec, &[9, 5, 3, 3, 1, 2, 4, 8, 10]);
+}