Merge pull request #57 from bluss/sort-in-place

Implement sorting in place for OrderMap, OrderSet

Author: bluss

benches/bench.rs

@@ -5,6 +5,7 @@ extern crate fnv;
 #[macro_use]
 extern crate lazy_static;
 
+use std::hash::Hash;
 use fnv::FnvHasher;
 use std::hash::BuildHasherDefault;
 type FnvBuilder = BuildHasherDefault<FnvHasher>;
@@ -361,13 +362,16 @@ fn lookup_orderedmap_10_000_noexist(b: &mut Bencher) {
 // number of items to look up
 const LOOKUP_MAP_SIZE: u32 = 100_000_u32;
 const LOOKUP_SAMPLE_SIZE: u32 = 5000;
+const SORT_MAP_SIZE: usize = 10_000;
 
 
+// use lazy_static so that comparison benchmarks use the exact same inputs
 lazy_static! {
     static ref KEYS: Vec<u32> = {
         shuffled_keys(0..LOOKUP_MAP_SIZE)
     };
 }
+
 lazy_static! {
     static ref HMAP_100K: HashMap<u32, u32> = {
         let c = LOOKUP_MAP_SIZE;
@@ -392,6 +396,25 @@ lazy_static! {
     };
 }
 
+lazy_static! {
+    static ref OMAP_SORT_U32: OrderMap<u32, u32> = {
+        let mut map = OrderMap::with_capacity(SORT_MAP_SIZE);
+        for &key in &KEYS[..SORT_MAP_SIZE] {
+            map.insert(key, key);
+        }
+        map
+    };
+}
+lazy_static! {
+    static ref OMAP_SORT_S: OrderMap<String, String> = {
+        let mut map = OrderMap::with_capacity(SORT_MAP_SIZE);
+        for &key in &KEYS[..SORT_MAP_SIZE] {
+            map.insert(format!("{:^16x}", &key), String::new());
+        }
+        map
+    };
+}
+
 #[bench]
 fn lookup_hashmap_100_000_multi(b: &mut Bencher) {
     let map = &*HMAP_100K;
@@ -643,3 +666,60 @@ fn many_retain_hashmap_100_000(b: &mut Bencher) {
         map
     });
 }
+
+
+// simple sort impl for comparison
+pub fn simple_sort<K: Ord + Hash, V>(m: &mut OrderMap<K, V>) {
+    let mut ordered: Vec<_> = m.drain(..).collect();
+    ordered.sort_by(|left, right| left.0.cmp(&right.0));
+    m.extend(ordered);
+}
+
+
+#[bench]
+fn ordermap_sort_s(b: &mut Bencher) {
+    let map = OMAP_SORT_S.clone();
+
+    // there's a map clone there, but it's still useful to profile this
+    b.iter(|| {
+        let mut map = map.clone();
+        map.sort_keys();
+        map
+    });
+}
+
+#[bench]
+fn ordermap_simple_sort_s(b: &mut Bencher) {
+    let map = OMAP_SORT_S.clone();
+
+    // there's a map clone there, but it's still useful to profile this
+    b.iter(|| {
+        let mut map = map.clone();
+        simple_sort(&mut map);
+        map
+    });
+}
+
+#[bench]
+fn ordermap_sort_u32(b: &mut Bencher) {
+    let map = OMAP_SORT_U32.clone();
+
+    // there's a map clone there, but it's still useful to profile this
+    b.iter(|| {
+        let mut map = map.clone();
+        map.sort_keys();
+        map
+    });
+}
+
+#[bench]
+fn ordermap_simple_sort_u32(b: &mut Bencher) {
+    let map = OMAP_SORT_U32.clone();
+
+    // there's a map clone there, but it's still useful to profile this
+    b.iter(|| {
+        let mut map = map.clone();
+        simple_sort(&mut map);
+        map
+    });
+}

benches/faststring.rs

@@ -1,16 +1,11 @@
 #![feature(test)]
 extern crate test;
 extern crate rand;
-extern crate fnv;
 extern crate lazy_static;
 
-use fnv::FnvHasher;
-use std::hash::BuildHasherDefault;
-type FnvBuilder = BuildHasherDefault<FnvHasher>;
-
 use test::Bencher;
 
-#[macro_use] extern crate ordermap;
+extern crate ordermap;
 
 use ordermap::OrderMap;
 

src/lib.rs

@@ -45,6 +45,11 @@ fn hash_elem_using<B: BuildHasher, K: ?Sized + Hash>(build: &B, k: &K) -> HashVa
 #[derive(Copy, Debug)]
 struct HashValue(usize);
 
+impl HashValue {
+    #[inline(always)]
+    fn get(self) -> usize { self.0 }
+}
+
 impl Clone for HashValue {
     #[inline]
     fn clone(&self) -> Self { *self }
@@ -1044,6 +1049,57 @@ impl<K, V, S> OrderMap<K, V, S>
         }
     }
 
+    /// Sort the map’s key-value pairs by the default ordering of the keys.
+    ///
+    /// See `sort_by` for details.
+    pub fn sort_keys(&mut self)
+        where K: Ord,
+    {
+        self.sort_by(|k1, _, k2, _| Ord::cmp(k1, k2))
+    }
+
+    /// Sort the map’s key-value pairs in place using the comparison
+    /// function `compare`.
+    ///
+    /// The comparison function receives two key and value pairs to compare (you
+    /// can sort by keys or values or their combination as needed).
+    ///
+    /// Computes in **O(n log n)** time and **O(n)** space. The sort is stable.
+    pub fn sort_by<F>(&mut self, mut compare: F)
+        where F: FnMut(&K, &V, &K, &V) -> Ordering,
+    {
+        // here we temporarily use the hash field in a bucket to store the old
+        // index instead.
+        //
+        // Save the old hash values in `side_index`.
+        // Then we can sort `self.entries` in place.
+        let mut side_index = Vec::from_iter(enumerate(&mut self.entries).map(|(i, elt)| {
+            replace(&mut elt.hash, HashValue(i)).get()
+        }));
+
+        self.entries.sort_by(move |ei, ej| compare(&ei.key, &ei.value, &ej.key, &ej.value));
+
+        // Here we write back the hash values from side_index and fill
+        // in side_index with a mapping from the old to the new index instead.
+        for (i, ent) in enumerate(&mut self.entries) {
+            let old_index = ent.hash.get();
+            ent.hash = HashValue(replace(&mut side_index[old_index], i));
+        }
+
+        // Apply new index to self.indices
+        dispatch_32_vs_64!(self.apply_new_index(&side_index));
+    }
+
+    fn apply_new_index<Sz>(&mut self, new_index: &[usize])
+        where Sz: Size
+    {
+        for pos in self.indices.iter_mut() {
+            if let Some((i, _)) = pos.resolve::<Sz>() {
+                pos.set_pos::<Sz>(new_index[i]);
+            }
+        }
+    }
+
     /// Sort the key-value pairs of the map and return a by value iterator of
     /// the key-value pairs with the result.
     ///

src/set.rs

@@ -342,6 +342,24 @@ impl<T, S> OrderSet<T, S>
         self.map.retain(move |x, &mut ()| keep(x))
     }
 
+    /// Sort the set’s values by their default ordering.
+    ///
+    /// See `sort_by` for details.
+    pub fn sort(&mut self)
+        where T: Ord,
+    {
+        self.map.sort_keys()
+    }
+
+    /// Sort the set’s values in place using the comparison function `compare`.
+    ///
+    /// Computes in **O(n log n)** time and **O(n)** space. The sort is stable.
+    pub fn sort_by<F>(&mut self, mut compare: F)
+        where F: FnMut(&T, &T) -> Ordering,
+    {
+        self.map.sort_by(move |a, _, b, _| compare(a, b));
+    }
+
     /// Sort the values of the set and return a by value iterator of
     /// the values with the result.
     ///

tests/quick.rs

@@ -273,6 +273,49 @@ quickcheck! {
         // check the order
         itertools::assert_equal(map.keys(), initial_map.keys().filter(|&k| !remove_map.contains_key(k)));
     }
+
+    fn sort_1(keyvals: Large<Vec<(i8, i8)>>) -> () {
+        let mut map: OrderMap<_, _> = OrderMap::from_iter(keyvals.to_vec());
+        let mut answer = keyvals.0;
+        answer.sort_by_key(|t| t.0);
+
+        // reverse dedup: Because OrderMap::from_iter keeps the last value for
+        // identical keys
+        answer.reverse();
+        answer.dedup_by_key(|t| t.0);
+        answer.reverse();
+
+        map.sort_by(|k1, _, k2, _| Ord::cmp(k1, k2));
+
+        // check it contains all the values it should
+        for &(key, val) in &answer {
+            assert_eq!(map[&key], val);
+        }
+
+        // check the order
+
+        let mapv = Vec::from_iter(map);
+        assert_eq!(answer, mapv);
+
+    }
+
+    fn sort_2(keyvals: Large<Vec<(i8, i8)>>) -> () {
+        let mut map: OrderMap<_, _> = OrderMap::from_iter(keyvals.to_vec());
+        map.sort_by(|_, v1, _, v2| Ord::cmp(v1, v2));
+        assert_sorted_by_key(map, |t| t.1);
+    }
+}
+
+fn assert_sorted_by_key<I, Key, X>(iterable: I, key: Key)
+    where I: IntoIterator,
+          I::Item: Ord + Clone + Debug,
+          Key: Fn(&I::Item) -> X,
+          X: Ord,
+{
+    let input = Vec::from_iter(iterable);
+    let mut sorted = input.clone();
+    sorted.sort_by_key(key);
+    assert_eq!(input, sorted);
 }
 
 #[derive(Clone, Debug, Hash, PartialEq, Eq)]