From 759e1fbcdbd746309cbe489c2c768e5714fb945a Mon Sep 17 00:00:00 2001
From: shuo <shuoli84@gmail.com>
Date: Thu, 16 Feb 2023 12:30:13 +0800
Subject: [PATCH 1/2] add grow_and_insert method

---
 benches/benches/benches.rs | 14 ++++++++++++++
 src/lib.rs                 | 24 ++++++++++++++++++++++++
 2 files changed, 38 insertions(+)

diff --git a/benches/benches/benches.rs b/benches/benches/benches.rs
index b8c4ba6..3165707 100644
--- a/benches/benches/benches.rs
+++ b/benches/benches/benches.rs
@@ -91,6 +91,19 @@ fn insert(c: &mut Criterion) {
     });
 }
 
+fn grow_and_insert(c: &mut Criterion) {
+    const N: usize = 1_000_000;
+    let mut fb = FixedBitSet::with_capacity(N);
+
+    c.bench_function("grow_and_insert", |b| {
+        b.iter(|| {
+            for i in 0..N {
+                fb.grow_and_insert(i);
+            }
+        })
+    });
+}
+
 fn union_with(c: &mut Criterion) {
     const N: usize = 1_000_000;
     let mut fb_a = FixedBitSet::with_capacity(N);
@@ -159,5 +172,6 @@ criterion_group!(
     symmetric_difference_with,
     count_ones,
     clear,
+    grow_and_insert,
 );
 criterion_main!(benches);
diff --git a/src/lib.rs b/src/lib.rs
index 23fea19..93b9424 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -123,6 +123,18 @@ impl FixedBitSet {
         }
     }
 
+    /// First grow to bits just like `grow`, then enable the bit
+    #[inline]
+    pub fn grow_and_insert(&mut self, bits: usize) {
+        self.grow(bits + 1);
+
+        let (blocks, rem) = div_rem(bits);
+        // SAFETY: The above grow ensures that the block is inside the Vec's allocation.
+        unsafe {
+            *self.data.get_unchecked_mut(blocks) |= 1 << rem;
+        }
+    }
+
     /// The length of the [`FixedBitSet`] in bits.
     ///
     /// Note: `len` includes both set and unset bits.
@@ -1043,6 +1055,18 @@ mod tests {
         assert!(fb.contains(64));
     }
 
+    #[test]
+    fn grow_and_insert() {
+        let mut fb = FixedBitSet::default();
+        for i in 0..100 {
+            if i % 3 == 0 {
+                fb.grow_and_insert(i);
+            }
+        }
+
+        assert_eq!(fb.count_ones(..), 34);
+    }
+
     #[test]
     fn test_toggle() {
         let mut fb = FixedBitSet::with_capacity(16);

From 16fcb19f3fb6c7b136afce646f079081534d6810 Mon Sep 17 00:00:00 2001
From: James Liu <contact@jamessliu.com>
Date: Thu, 16 Feb 2023 12:11:31 -0800
Subject: [PATCH 2/2] Update doc comment in grow_and_insert

---
 src/lib.rs | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/lib.rs b/src/lib.rs
index 93b9424..b34e11d 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -123,7 +123,11 @@ impl FixedBitSet {
         }
     }
 
-    /// First grow to bits just like `grow`, then enable the bit
+    /// Grows the internal size of the bitset before inserting a bit
+    ///
+    /// Unlike `insert`, this cannot panic, but may allocate if the bit is outside of the existing buffer's range.
+    ///
+    /// This is faster than calling `grow` then `insert` in succession.
     #[inline]
     pub fn grow_and_insert(&mut self, bits: usize) {
         self.grow(bits + 1);