Import smallvec-1.4.0

Change-Id: I88441e5cd5fd487e273152f2b28461529b1f368c

1 files changed, 295 insertions, 0 deletions

diff --git a/benches/bench.rs b/benches/bench.rs
new file mode 100644
index 0000000..36cb133
--- /dev/null
+++ b/benches/bench.rs
@@ -0,0 +1,295 @@
+#![feature(test)]
+
+#[macro_use]
+extern crate smallvec;
+extern crate test;
+
+use self::test::Bencher;
+use smallvec::{ExtendFromSlice, SmallVec};
+
+const VEC_SIZE: usize = 16;
+const SPILLED_SIZE: usize = 100;
+
+trait Vector<T>: for<'a> From<&'a [T]> + Extend<T> + ExtendFromSlice<T> {
+    fn new() -> Self;
+    fn push(&mut self, val: T);
+    fn pop(&mut self) -> Option<T>;
+    fn remove(&mut self, p: usize) -> T;
+    fn insert(&mut self, n: usize, val: T);
+    fn from_elem(val: T, n: usize) -> Self;
+    fn from_elems(val: &[T]) -> Self;
+}
+
+impl<T: Copy> Vector<T> for Vec<T> {
+    fn new() -> Self {
+        Self::with_capacity(VEC_SIZE)
+    }
+
+    fn push(&mut self, val: T) {
+        self.push(val)
+    }
+
+    fn pop(&mut self) -> Option<T> {
+        self.pop()
+    }
+
+    fn remove(&mut self, p: usize) -> T {
+        self.remove(p)
+    }
+
+    fn insert(&mut self, n: usize, val: T) {
+        self.insert(n, val)
+    }
+
+    fn from_elem(val: T, n: usize) -> Self {
+        vec![val; n]
+    }
+
+    fn from_elems(val: &[T]) -> Self {
+        val.to_owned()
+    }
+}
+
+impl<T: Copy> Vector<T> for SmallVec<[T; VEC_SIZE]> {
+    fn new() -> Self {
+        Self::new()
+    }
+
+    fn push(&mut self, val: T) {
+        self.push(val)
+    }
+
+    fn pop(&mut self) -> Option<T> {
+        self.pop()
+    }
+
+    fn remove(&mut self, p: usize) -> T {
+        self.remove(p)
+    }
+
+    fn insert(&mut self, n: usize, val: T) {
+        self.insert(n, val)
+    }
+
+    fn from_elem(val: T, n: usize) -> Self {
+        smallvec![val; n]
+    }
+
+    fn from_elems(val: &[T]) -> Self {
+        SmallVec::from_slice(val)
+    }
+}
+
+macro_rules! make_benches {
+    ($typ:ty { $($b_name:ident => $g_name:ident($($args:expr),*),)* }) => {
+        $(
+            #[bench]
+            fn $b_name(b: &mut Bencher) {
+                $g_name::<$typ>($($args,)* b)
+            }
+        )*
+    }
+}
+
+make_benches! {
+    SmallVec<[u64; VEC_SIZE]> {
+        bench_push => gen_push(SPILLED_SIZE as _),
+        bench_push_small => gen_push(VEC_SIZE as _),
+        bench_insert => gen_insert(SPILLED_SIZE as _),
+        bench_insert_small => gen_insert(VEC_SIZE as _),
+        bench_remove => gen_remove(SPILLED_SIZE as _),
+        bench_remove_small => gen_remove(VEC_SIZE as _),
+        bench_extend => gen_extend(SPILLED_SIZE as _),
+        bench_extend_small => gen_extend(VEC_SIZE as _),
+        bench_from_iter => gen_from_iter(SPILLED_SIZE as _),
+        bench_from_iter_small => gen_from_iter(VEC_SIZE as _),
+        bench_from_slice => gen_from_slice(SPILLED_SIZE as _),
+        bench_from_slice_small => gen_from_slice(VEC_SIZE as _),
+        bench_extend_from_slice => gen_extend_from_slice(SPILLED_SIZE as _),
+        bench_extend_from_slice_small => gen_extend_from_slice(VEC_SIZE as _),
+        bench_macro_from_elem => gen_from_elem(SPILLED_SIZE as _),
+        bench_macro_from_elem_small => gen_from_elem(VEC_SIZE as _),
+        bench_pushpop => gen_pushpop(),
+    }
+}
+
+make_benches! {
+    Vec<u64> {
+        bench_push_vec => gen_push(SPILLED_SIZE as _),
+        bench_push_vec_small => gen_push(VEC_SIZE as _),
+        bench_insert_vec => gen_insert(SPILLED_SIZE as _),
+        bench_insert_vec_small => gen_insert(VEC_SIZE as _),
+        bench_remove_vec => gen_remove(SPILLED_SIZE as _),
+        bench_remove_vec_small => gen_remove(VEC_SIZE as _),
+        bench_extend_vec => gen_extend(SPILLED_SIZE as _),
+        bench_extend_vec_small => gen_extend(VEC_SIZE as _),
+        bench_from_iter_vec => gen_from_iter(SPILLED_SIZE as _),
+        bench_from_iter_vec_small => gen_from_iter(VEC_SIZE as _),
+        bench_from_slice_vec => gen_from_slice(SPILLED_SIZE as _),
+        bench_from_slice_vec_small => gen_from_slice(VEC_SIZE as _),
+        bench_extend_from_slice_vec => gen_extend_from_slice(SPILLED_SIZE as _),
+        bench_extend_from_slice_vec_small => gen_extend_from_slice(VEC_SIZE as _),
+        bench_macro_from_elem_vec => gen_from_elem(SPILLED_SIZE as _),
+        bench_macro_from_elem_vec_small => gen_from_elem(VEC_SIZE as _),
+        bench_pushpop_vec => gen_pushpop(),
+    }
+}
+
+fn gen_push<V: Vector<u64>>(n: u64, b: &mut Bencher) {
+    #[inline(never)]
+    fn push_noinline<V: Vector<u64>>(vec: &mut V, x: u64) {
+        vec.push(x);
+    }
+
+    b.iter(|| {
+        let mut vec = V::new();
+        for x in 0..n {
+            push_noinline(&mut vec, x);
+        }
+        vec
+    });
+}
+
+fn gen_insert<V: Vector<u64>>(n: u64, b: &mut Bencher) {
+    #[inline(never)]
+    fn insert_noinline<V: Vector<u64>>(vec: &mut V, p: usize, x: u64) {
+        vec.insert(p, x)
+    }
+
+    b.iter(|| {
+        let mut vec = V::new();
+        // Add one element, with each iteration we insert one before the end.
+        // This means that we benchmark the insertion operation and not the
+        // time it takes to `ptr::copy` the data.
+        vec.push(0);
+        for x in 0..n {
+            insert_noinline(&mut vec, x as _, x);
+        }
+        vec
+    });
+}
+
+fn gen_remove<V: Vector<u64>>(n: usize, b: &mut Bencher) {
+    #[inline(never)]
+    fn remove_noinline<V: Vector<u64>>(vec: &mut V, p: usize) -> u64 {
+        vec.remove(p)
+    }
+
+    b.iter(|| {
+        let mut vec = V::from_elem(0, n as _);
+
+        for x in (0..n - 1).rev() {
+            remove_noinline(&mut vec, x);
+        }
+    });
+}
+
+fn gen_extend<V: Vector<u64>>(n: u64, b: &mut Bencher) {
+    b.iter(|| {
+        let mut vec = V::new();
+        vec.extend(0..n);
+        vec
+    });
+}
+
+fn gen_from_iter<V: Vector<u64>>(n: u64, b: &mut Bencher) {
+    let v: Vec<u64> = (0..n).collect();
+    b.iter(|| {
+        let vec = V::from(&v);
+        vec
+    });
+}
+
+fn gen_from_slice<V: Vector<u64>>(n: u64, b: &mut Bencher) {
+    let v: Vec<u64> = (0..n).collect();
+    b.iter(|| {
+        let vec = V::from_elems(&v);
+        vec
+    });
+}
+
+fn gen_extend_from_slice<V: Vector<u64>>(n: u64, b: &mut Bencher) {
+    let v: Vec<u64> = (0..n).collect();
+    b.iter(|| {
+        let mut vec = V::new();
+        vec.extend_from_slice(&v);
+        vec
+    });
+}
+
+fn gen_pushpop<V: Vector<u64>>(b: &mut Bencher) {
+    #[inline(never)]
+    fn pushpop_noinline<V: Vector<u64>>(vec: &mut V, x: u64) -> Option<u64> {
+        vec.push(x);
+        vec.pop()
+    }
+
+    b.iter(|| {
+        let mut vec = V::new();
+        for x in 0..SPILLED_SIZE as _ {
+            pushpop_noinline(&mut vec, x);
+        }
+        vec
+    });
+}
+
+fn gen_from_elem<V: Vector<u64>>(n: usize, b: &mut Bencher) {
+    b.iter(|| {
+        let vec = V::from_elem(42, n);
+        vec
+    });
+}
+
+#[bench]
+fn bench_insert_many(b: &mut Bencher) {
+    #[inline(never)]
+    fn insert_many_noinline<I: IntoIterator<Item = u64>>(
+        vec: &mut SmallVec<[u64; VEC_SIZE]>,
+        index: usize,
+        iterable: I,
+    ) {
+        vec.insert_many(index, iterable)
+    }
+
+    b.iter(|| {
+        let mut vec = SmallVec::<[u64; VEC_SIZE]>::new();
+        insert_many_noinline(&mut vec, 0, 0..SPILLED_SIZE as _);
+        insert_many_noinline(&mut vec, 0, 0..SPILLED_SIZE as _);
+        vec
+    });
+}
+
+#[bench]
+fn bench_insert_from_slice(b: &mut Bencher) {
+    let v: Vec<u64> = (0..SPILLED_SIZE as _).collect();
+    b.iter(|| {
+        let mut vec = SmallVec::<[u64; VEC_SIZE]>::new();
+        vec.insert_from_slice(0, &v);
+        vec.insert_from_slice(0, &v);
+        vec
+    });
+}
+
+#[bench]
+fn bench_macro_from_list(b: &mut Bencher) {
+    b.iter(|| {
+        let vec: SmallVec<[u64; 16]> = smallvec![
+            0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 20, 24, 32, 36, 0x40, 0x80,
+            0x100, 0x200, 0x400, 0x800, 0x1000, 0x2000, 0x4000, 0x8000, 0x10000, 0x20000, 0x40000,
+            0x80000, 0x100000,
+        ];
+        vec
+    });
+}
+
+#[bench]
+fn bench_macro_from_list_vec(b: &mut Bencher) {
+    b.iter(|| {
+        let vec: Vec<u64> = vec![
+            0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 20, 24, 32, 36, 0x40, 0x80,
+            0x100, 0x200, 0x400, 0x800, 0x1000, 0x2000, 0x4000, 0x8000, 0x10000, 0x20000, 0x40000,
+            0x80000, 0x100000,
+        ];
+        vec
+    });
+}